Band 43, Heft 1

A quantitative investigation of poly(vinyl) chloride (PVC) de-chlorination using Fe 2 O 3 , together with the impact of SiO 2 addition on the co-pyrolysis of PVC and Fe 2 O 3 , was conducted below 673 K in an Ar atmosphere aiming to cut the emission of gaseous Cl⁻ products. It was found that chlorine in PVC can be fixed in FeCl 2 by the reaction between PVC and Fe 2 O 3 . The co-pyrolysis of PVC and Fe 2 O 3 proceeds in two stages with a temperature boundary of around 543 K. Below 543 K, a direct reaction occurs between PVC and Fe 2 O 3 , resulting in a small mass loss ratio and some extent of chlorine fixing ratio in FeCl 2 . However, above 543 K, PVC starts to decompose to release gaseous H 2 , HCl, etc., which react with Fe 2 O 3 through two possible pathways to form FeCl 2 . In Pathway 1, first Fe 2 O 3 is reduced to Fe 3 O 4 by H 2 , followed by the chlorination of Fe 3 O 4 to FeCl 2 by HCl. In Pathway 2, first Fe 2 O 3 is chlorinated to FeCl 3 by HCl, followed by the reduction of FeCl 3 to FeCl 2 by H 2 . The chlorine fixing ratio in FeCl 2 and the volatile generation ratio increase with decreasing PVC content in the initial mixtures. The addition of SiO 2 promotes the chlorine fixing ratio in FeCl 2 and volatile generation, and the impact gets stronger with decreasing PVC content in the mixtures. The chlorine fixing ratio is increased from 70.8 to 82.6% by SiO 2 addition for the mixtures containing 25% PVC, whereas the difference in the chlorine fixing ratio in FeCl 2 caused by SiO 2 addition is negligible for the mixtures containing 90% PVC. Fayalite (Fe 2 SiO 4 ) was not detected in the solid residues after the experiments. After separating FeCl 2 using water leaching, the filter residue, a composite of iron oxide and conjugated polyene, can be used as a raw material for iron-making.

This study is a process for the preparation of advanced nickel–iron alloys by selective reduction of nickel-poor laterite ores using a variety of reducing agents. The first part of the experiment was the reduction of nickel laterite ore using natural gas; the reduction yielded mostly nickel metal and a small amount of iron forming fine nickel–iron particles. Fine nickel–iron particles are formed through the reduction of nickel and a small amount of iron oxides. These particles are dispersed and embedded within silicates. Additionally, H 2 S present in natural gas reacts with iron oxide, resulting in the formation of FeS. This, in turn, forms a low melting point eutectic with Fe, which reduces surface tension and promotes the growth and aggregation of nickel–iron particles. This study aimed to investigate the effects of various parameters such as roasting temperature, roasting time, natural gas concentration, and nickel laterite pellet on the formation and aggregation of ferronickel particles in low-grade nickel laterite ores. The results showed that the optimum reduction parameters were achieved at 900°C, 120 min, 40% natural gas concentration, and 40–60 mesh nickel laterite size, with roasting temperature being the most important factor followed by natural gas concentration, roasting time, and nickel laterite pellet. Using these parameters, the metallization rates of Ni and Fe were found to be as high as 95.3 and 8.5%, respectively.

The loss of boron (B) in the rack plate steel during the electroslag remelting process has a significant impact on its mechanical properties. Therefore, it is necessary to design appropriate slags to suppress the loss of B. CaF 2 –CaO–Al 2 O 3 phase diagram was calculated to determine the basic slag. The influence of MgO and B 2 O 3 on the performance of the basic slag was studied to determine the optimal amount of MgO addition. The equilibrium reactions between rack plate steel and the 50.48 mass% CaF 2 –24.81 mass% CaO–24.71 mass% Al 2 O 3 –2 mass% MgO- y mass% B 2 O 3 ( y was 1–10) slag were studied to examine the variation in B content in the steel. Results indicate the presence of a temperature-qualified eutectic point in the CaF 2 –CaO–Al 2 O 3 phase diagram. With an increase in MgO content in the slag, the melting temperature of the basic slag initially decreases and then increases, while the electrical conductivity decreases. On the other hand, B 2 O 3 reduces the melting point of the slag and increases the equilibrium B content in the steel. The 50.48 mass% CaF 2 –24.81 mass% CaO–24.71 mass% Al 2 O 3 –2 mass% MgO- y mass% B 2 O 3 ( y was 5–7) slag can achieve the target range of B content in the steel, and its viscosity meets the requirements of electric slag remelting.

Ultra-thin grain-oriented electrical steel with a thickness of 80 µm is produced by one-step-rolling with industrial grain-oriented electrical steel. The research employs electron back-scattering texture analysis technique to investigate the evolution of deformation and recrystallization textures in this specific steel. Emphasis is placed on examining the origin of {113}<361> grains and their consequential impact on secondary recrystallization. It is revealed that primary, secondary, and tertiary recrystallization phases are integral during the annealing process. The origin of surface {113}<361> grains were result of initial deviated Goss grains with specific shear deformation behavior in cold rolled ultra-thin strips. Additionally, the influence of these grains on texture evolution is predominantly evident during secondary recrystallization. These grains potentially undergo abnormal growth in secondary recrystallization, exploiting high-energy grain boundaries among Goss grains. This phenomenon consequently leads to the diminution of the sharp Goss texture formed during primary recrystallization. Given the magnetic properties and predominant applications of ultra-thin grain-oriented electrical steel in medium-frequency fields, it is recommended to prepare ultra-thin grain-oriented steel during primary recrystallization phase.

A generalized three-dimensional mathematical model is built to study the influences of channel parameters (channel angle, channel section diameter, and channel distance) on the molten steel flow, heat transfer, and inclusion removal in the induction heating tundish. The results demonstrate that as the channel angle increases, the flow of molten steel in the discharging chamber gradually slows down. When the channel angle is 6°, the temperature of the discharging chamber is slightly lower than when the channel angles are 2° and 4°. When the channel angle is 2°, the inclusion removal rate is lower than when the channel angles are 4° and 6°, while the latter two have little difference. As the channel section diameter increases, the flow of molten steel in the discharging chamber gradually slows down. When the channel section diameter is 100 mm, the temperature distribution in the discharging chamber is uneven. While the temperature distributions of the discharging chamber are even and similar, when the channel section diameters are 150 and 200 mm. As the channel section diameter increases, the removal rate of inclusion gradually decreases. The variation of channel distance has little effect on the temperature distribution of the discharging chamber. When the channel distance is 600 mm, the removal rate of inclusion is lower than when the channel distances are 1,000 and 1,400 mm. Moreover, for the latter two, the removal rates of inclusions have little difference. For this model, the best channel angle is 4°, the best channel section diameter is 150 mm, and the best channel distance is 1,000 mm.

Macroscopic and microscopic textures of non-oriented silicon steel hot rolled sheets with different rare-earth Ce contents were investigated using X-Ray Diffraction, Electron Back Scatter Diffraction, and field emission scanning electron microscopy, and the magnetic properties of the cold-rolled annealed sheets were examined using a silicon steel sheet testing system. The results show that the addition of rare-earth Ce reduces the proportion of unfavorable γ texture intensity and texture {111} and enhances the proportion of favorable η texture intensity and texture {100} and {110} in the steel. Magnetic property tests show that rare-earth Ce favors the reduction in test steel loss and the increase in magnetic susceptibility. The main reason is that rare-earth Ce combines with O and S in steel to form large-size inclusions, which preferentially precipitate in the liquid steel and inhibit the precipitation of fine AlN and MnS inclusions, while denaturing the inclusions to spherical composite inclusions such as Ce 2 O 2 S-MnS, CeS-AlN, and CeAlO 3 , thus exerting a good effect of purifying the liquid steel and denaturing the inclusions.

To improve the photoelectric conversion efficiency ( η ) of the solar cell, a green wavelength (532 nm) laser source in a nanosecond range was used to ablate the passivated emitter and rear cell (PERC) to form the contact holes. If the laser ablation hole opening process was not set properly, the diameter or the external expansion of holes would be too large, causing the decline of the PERC performance. The Gaussian distribution of the laser is regulated by the output power ( P o ) and the repetition frequency ( f rep ) of the incident pulse laser, so that the optimized morphology of holes is obtained on the back of the PERC solar cells. After the contact holes are screen printed by the aluminum paste, the local back surface field is finally formed. The experimental results showed that the outward expansion decreases obviously with the increase of laser P o . Second, the spacing of the holes decreases with the increase of the laser f rep . It was found that under the laser P o of 33.0 W and f rep of 1,400 kHz, the η of the industrial PERC solar cells was the highest. The Quokka simulations indicated that small outward expansion, small diameter, and long spacing of holes would further decrease the recombination parameter in the rear surface. With the optimized morphology of contact holes and the low contact resistance, the PERC cell’s calculated V oc and η improvements were 6.5 mV and 0.48%, respectively, which was verified with experimental findings.

The effect of lining materials (Al 2 O 3 and Al 2 O 3 –MgO·Al 2 O 3 ) of ladle on evolution of non-metallic inclusions in aluminum-killed (Al-killed) steel during ladle furnace refining without Ca treatment was investigated through industrial experiments. The results showed that non-metallic inclusions experienced the changes from Al 2 O 3 → MgO–Al 2 O 3 → CaO–Al 2 O 3 . During the refining process using either of the two ladle lining materials, for all non-metallic inclusions, the vast majority are distributed in the high Al 2 O 3 area of the CaO–Al 2 O 3 –MgO phase diagram, with very little or none in the low melting point zone. Non-metallic inclusions are mainly smaller than 3 μm, while those larger than 3 μm consisted primarily of MgO·Al 2 O 3 and CaO–Al 2 O 3 inclusions. The use of an Al 2 O 3 –MgO·Al 2 O 3 -lining ladle is more effective in reducing the number density of inclusions in the steel. However, during the refining process, the Al 2 O 3 -lining ladle does not have a significant impact on the presence of MgO–Al 2 O 3 and CaO–Al 2 O 3 inclusions in the molten steel. The Al 2 O 3 –MgO·Al 2 O 3 -lining ladle does not have a significant effect on MgO–Al 2 O 3 inclusions, but it does promote the formation of CaO–Al 2 O 3 and CaS inclusions in the molten steel.

The relevant experiments and studies were conducted to address the metallurgical defects such as subcutaneous bubbles and slag inclusions occurring during the enamel steel continuous casting process. According to the high-temperature experimental results, calculations were made to determine the changes in viscosity and tension due to the steel reaction with the slag. Based on the experimental findings, there was a notable variation in the content of SiO 2 and Al 2 O 3 in the slag before and after the reaction. The concentration of the element Al in the steel melt significantly decreased, whereas the concentration of Ti showed a minimal change. These observations indicate that the reduction of SiO 2 at the slag–steel interface is predominantly attributed to the role of Al. The calculation results showed that at 300 s of reaction time, the viscosity rapidly increased from 0.108 to 0.133 Pa·s and then slowly increased to 0.155 Pa·s; The interfacial tension rapidly decreased from its initial value of 1,380 mJ·m −2 to a minimum of 1,320 mJ·m −2 , and it then slowly increased to an equilibrium state. Therefore, the main cause of the occurrence of porosity defects in the enamel steel continuous casting process is the reduction of interfacial tension between slag, steel, and gas caused by the reaction between the slag and steel, as well as the foaming of the slag.

Rebar is an extremely important building material. The cooling rate and the presence of niobium (Nb) element are key factors influencing the overall performance of rebars. In this work, the high-strength rebar’s microstructure, precipitated phase, and mechanical properties were characterized using scanning electron microscopy, transmission electron microscopy, HVS-1000 hardness tester, and MTS810 universal tensile testing machine. The results showed that a shift in cooling rate from 0.3 to 3°C·s −1 resulted in noticeable changes in the microstructures of rebars, particularly between Nb-free and Nb-containing variants. In the case of Nb-containing rebars, there was an increase of 8.26% in the proportion of pearlite, along with a decrease of 10.63 μm in the average grain size of ferrite. Furthermore, the lamellar spacing of pearlite experienced a decrease of 0.0495 μm, the proportion of low-angle grain boundaries saw an increment of 4.13%, and the size of the precipitated phase (Nb, Ti, V) C reduced by 18.9 nm. These changes collectively led to a significant increase in hardness (98.56 HV), yield strength (179.02 MPa), and ultimate strength (199.43 MPa). The resultant fracture morphology manifested as a dimple pattern.

In this study, three types of 304 stainless steel samples with different strengths were prepared by refining the grain size through rolling. The microstructure of the samples was observed by electron microscopy. The influence of grain size on the static tensile properties and fatigue strength of the material is mainly attributed to changes in the plastic deformation fracture mechanism and micro-deformation mechanism. In addition, a new fatigue strength prediction model is proposed based on the influence of tensile strength and work-hardening capacity. Compared with the staircase method and Basquin formula models, the proposed model maintains the accuracy of fatigue strength prediction while reducing the cost of fatigue experiments. This provides a new approach for predicting the fatigue strength of specific materials and improving anti-fatigue design capabilities.

In this work, normal manufacture of a B-bearing steel was hampered by cracks in steel. In order to control these cracks, the formation mechanism has been examined through a comprehensive analysis of crack morphology, element segregation, high temperature mechanical properties, and precipitates. The high-temperature thermoplastic capabilities of the steel were found to be reduced by boron nitride particles precipitated at grain boundary. This led to the formation of a brittle zone in the straightening zone of the continuous casting process, which in turn caused cracks. Based on the formation mechanism of these cracks, the cracks were successfully controlled by adding an appropriate amount of Ti element to the steel and reducing the charging temperature of the heating furnace.

The gas flow distribution inside a blast furnace affects its smelting. Laser surface detection technology can control the gas flow distribution and promote the stable and smooth running of blast furnace by observing and adjusting the surface condition in the blast furnace in real-time. The laser surface inspection technology in blast furnace gas flow control and optimization was introduced, with Masteel 4,000 m 3 blast furnace as an example. The results showed that the 30 W high-power laser had good penetration performance and could obtain clear scanning images of the material surface. In the process of strengthening smelting, the laser detection system determined that the central airflow of blast furnace was insufficient, resulting in a decrease in furnace condition stability, and promptly took measures to adjust the angle of the mineral coke fabric equipment and lifting line. After adjusting the material line, the central airflow was properly suppressed and stabilized, the angle of edge platform increased, the airflow developed properly, and two suitable gas flows were formed, which finally stabilized the furnace condition. Meanwhile, the small duct airflow other than the central airflow was found in time through the laser detection system, which provided conditions for operators to take measures to effectively eliminate the duct airflow, thereby avoiding big impacts on the blast furnace operation and technical and economic indexes. Therefore, the laser surface detection technology could effectively judge the gas flow distribution in the furnace, which contributed to timely adjustment of process parameters and optimization of blast furnace operation.

Based on the raw material of ammonium tetramolybdate in the experiment, molybdenum trioxide was prepared by hydrothermal synthesis, and the effects of different pH, hydrothermal reaction time, filling degree, and calcination temperature on molybdenum trioxide powder were studied. Meanwhile, the molybdenum trioxide powder was characterized through scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and thermal analysis differential scanning calorimetry analysis so as to study the morphology and phase changes during the experiment. As is evident from the research findings, MoO 3 powders with uniform and suitable size, smooth and clear surface, good dispersibility, and no adhesion can be obtained at the conditions of pH = 1, 16 h hydrothermal reaction, 90% of filling degree, and 550°C of calcination temperature. In the calcination process, MoO 3 crystal undergone crystal transformation and was completely transformed from h-MoO 3 to α-MoO 3 at the calcination temperature of 350°C.

The Ti-bearing oxides are introduced into HRB400 steel melt through external addition method (EAM, TiO 2 ) and internal precipitation method (IPM, Ti alloy) using a vacuum induction furnace, respectively. For each experiment, the instantaneous evolution of oxide properties was investigated through the analysis of intermediate samples. For the EAM method, it was found that the titanium content gradually increased with increase in the treatment time. Similar increasing trend is also observed for Ti-bearing oxide properties, such as the number density and normalized titanium content. These phenomena are totally different from those in the IPM intermediate samples, in which both Ti content and Ti-bearing oxide features show rapid increase, reaching saturation at 1 min after the addition of Ti alloy, and remain relatively stable thereafter. This comparison hints that after TiO 2 addition, they first dissolve in molten steel, then decompose, and finally again form Ti-bearing oxides. Furthermore, in the case of similar titanium content, EAM intermediate samples exhibit higher Ti-bearing oxide number density and higher normalized titanium content compared to IPM samples. After heat treatment, the intragranular ferrite nucleation was observed in cast sample of EAM, which was induced by the introduced Ti-bearing oxides.

309 stainless steel is one of the steels that have the highest resistance to corrosion and thermal oxidation compared to other steel grades, but it should not be used at temperatures higher than 980°C if there are temperature fluctuations. Additionally, 309 stainless steel is not designed for use in wet environments and has the least corrosion resistance. This study aims to cover 309 stainless steel with MgO/ZrO 2 particles using a two-step electroplating deposition method and then sintering to increase its resistance to wet corrosion and oxidation in temperature fluctuations. The intermediate ZrO 2 coating makes the outer MgO layer about two times thicker and reduces the corrosion current density. The morphology of the coatings was determined using scanning electron microscopy and X-ray diffraction, and oxidation resistance was determined using cyclic oxidation tests and the wet corrosion test of the corrosion solution. 3.5% NaCl was used. The results showed that the coated samples, due to the use of TiO 2 middle layer and MgO protective layer in the electrochemical method, have a 2-fold increase in wet corrosion and an increase in hardness of about 77%, as well as an increase in oxidation resistance of 1.8% compared to the sample without coating. Also, the reason for using the electrochemical deposition method is for better surface smoothness and less porosity of the coating as well as its use on all metals compared to thermal spray methods.

In this study, the effects of applying a full oxygen blast furnace (FOBF) on carbon emissions were investigated by determining the ultimate minimum carbon consumption and a carbon metabolism calculation model. The results demonstrate that the minimum coke ratio of the top gas circulation-FOBF (TGR-FOBF) is significantly reduced (from 270 to 207 kg·thm −1 ) compared to that of the traditional ironmaking blast furnace (TBF). Owing to the complete recycling of the furnace top gas of the TGR-FOBF, the degree of direct reduction of TGR-FOBF significantly decreased to 0.14. The replacement of the TGR-FOBF with the three TBFs significantly reduced the CO 2 emissions, which were the highest at 1.761 t-CO 2 /t-CS. Most of the CO 2 emissions were generated by the direct combustion emissions (CDE) and direct process emissions (PDE), with a small amount generated by the electricity indirect emissions (EIE). The CO 2 emissions generated by CDE, PDE, and EIE were 0.872 t-CO 2 /t-CS, 0.840 t-CO 2 /t-CS, and 0.049 t-CO 2 /t-CS, respectively. As the amount of TGR-FOBF replaced with the three TBFs increased, the CO 2 emissions generated by the CDE and PDE significantly decreased. When all three TBFs were replaced with TGR–FOBF, the CO 2 emissions generated by the CDE and PDE decreased to extremely low levels of 0.267 t-CO 2 /t-CS and 0.065 t-CO 2 /t-CS, respectively.

The use of self-sharpening cutters can increase crop survival and regrowth by reducing the extent of stem damage incurred during the mowing stage and reducing the healing time at the harvest site. In this study, a self-sharpening cutter was prepared using a two-stage rare earth catalytic carbon–nitrogen–boron co-infiltration process, and the self-sharpening and wear-resistant properties of the cutter were verified by using metallographic organization testing, hardness testing, friction and wear performance testing, and the homemade tool wear test bench, and the low-damage cutting characteristics of the cutter were examined through field tests on alfalfa. The results show that the thickness of the penetration layer on the back face of a self-sharpening cutter made of gradient material is about 800 μm, with a maximum hardness of 1,800 HV. The coefficient of friction of the gradient material self-sharpening cutter is 67% lower than that of the commercially available 65Mn cutter. Gradient material self-sharpening cutter wear resistance is 2.15 times more than that of commercially available 65Mn cutter. The gradient material self-sharpening cutter reduces cutting damage by 11.42% compared to the commercially available 65Mn cutter. The application and promotion of self-sharpening cutting blades with gradient materials reduce alfalfa cutting damage, thereby improving reproductive yield.

Macroscopic deformation and microstructural evolution simultaneously exist in the hot forming processes of superalloy. In order to effectively and accurately study the hot forming processes of superalloy turbine disk with the numerical simulation method, a multi-scale finite element model of GH4065 superalloy turbine disk involving macroscopic and microscopic aspects was established by defining macro- and micromaterial model of superalloy, hot forming processing parameters, and boundary conditions. Via the numerical simulations of superalloy turbine disk, the macroscopic material flow and microstructural evolution behaviors in the hot forming processes of superalloy turbine disk were studied. Besides, the macroscopic deformation and microstructure distribution states after the hot forming processes were revealed and analyzed. A corresponding hot forming physical test of superalloy turbine disk was conducted to verify the results of the numerical simulation. Via the qualitative and quantitative analyses, it was concluded that the macroscopic deformation and microstructural evolution in the hot forming processes of superalloy turbine disk can be accurately predicted by the numerical simulation method.

To enhance the efficiency and sustainability, technical preparations were made for eliminating the Temperature, Sample, Oxygen test of basic oxygen furnace (BOF) steelmaking process in this work. Utilizing data from 13,528 heats and state-of-the-art (SOTA) machine learning (ML) and deep learning algorithms, data-driven models with different types of inputs were developed, marking the first use of time series data (off-gas profiles and blowing practice related curves) for BOF steelmaking’s endpoint prediction, and the tabular features were expanded to 45. The prediction targets are molten steel’s concentrations of phosphorus (Endpoint [P], %) and carbon (Endpoint [C], %), and temperature (Endpoint-Temp, °C). The optimal models for each target were implemented at a Hesteel Group’s BOF steelmaking facility. Initially, SOTA ML models (XGBoost, LightGBM, Catboost, TabNet) were employed to predict Endpoint [P]/[C]/Temp with tabular data. The best mean absolute errors (MAE) achieved were 2.276 × 10 −3 % (Catboost), 6.916 × 10 −3 % (Catboost), and 7.955°C (LightGBM), respectively, which surpassed the conventional models’ performance. The prediction MAEs of the conventional models with the same inputs for Endpoint [P]/[C]/Temp were 3.158 × 10 −3 %, 7.534 × 10 −3 %, and 9.150°C (Back Propagation neural network) and 2.710 × 10 −3 %, 7.316 × 10 −3 %, and 8.310°C (Support Vector Regression). Subsequently, predictions were explored to be made using SOTA time series analysis models (1D ResCNN, TCN, OmniScaleCNN, eXplainable Convolutional neural network (XCM), Time-Series Transformer, LSTM-FCN, D-linear) with the original time series data and SOTA image analysis models (Pre-activation ResNet, DenseNet, DLA, Dual path networks (DPN), GoogleNet, Vision Transformer) with resized time series data. Finally, the concat-model and the paral-model architectures were designed for making predictions with both tabular data and time series data. It was determined that the concat-Model with TCN and ResCNN as the backbone exhibited the highest accuracy. It’s MAE for predicting Endpoint [P]/[C]/Temp reaches 2.153 × 10 −3 %, 6.413 × 10 −3 %, and 5.780°C, respectively, with field test’s MAE at 2.394 × 10 −3 %, 6.231 × 10 −3 %, and 7.679°C. Detailed results of the importance analysis for tabular data and time series are provided.

Three parts of the experiment were mainly carried out in this research: the effect of Ca on inclusions in 38CrMoAl high aluminum steel under atmospheric pressure, the effect of pressure on the solubility of Ca in pure iron under pressurized conditions, and the effect of Ca on inclusions in 38CrMoAl high aluminum steel under pressurized conditions. The results indicated that Ca can significantly transform the inclusions such as Al 2 O 3 and MgO·Al 2 O 3 with high melting points into calcium aluminate inclusions with low melting points. It was found that the pressure condition can significantly improve the solubility of Ca in pure iron and molten steel, which provided reliable data reference and guidance for popularizing Ca treatment of steel under pressure conditions in the future. Finally, the mechanism of inclusion transformation after Ca treatment was put forward. In this study, the theoretical calculation of thermodynamics was closely compared with the experimental data. It was proposed that to modify the inclusions in high aluminum steel into calcium aluminate inclusions with low melting points, it is necessary to accurately control Ca in the target region.

The synergy between Nb/Ti strengthening and precise isothermal transformation temperatures has resulted in the optimal microstructure and mechanical properties in Nb/Ti anti-seismic rebars. The microstructure, precipitates, and mechanical properties of experimental steels at different isothermal transformation temperatures were characterized using scanning electron microscopy, transmission electron microscopy, electron backscatter diffraction, and universal tensile testing machine. As the isothermal transformation temperature decreased from 700 to 600°C, the ferrite grain size, pearlite interlamellar spacing, and carbon diffusion coefficient of the experimental steel decreased to 6.69 μm, 0.17 μm, and 0.14 cm 2 ·s −1 , respectively, while the yield strength and tensile strength increased to 584 and 714 MPa, respectively. At 600°C, the pearlite transformation rate in the experimental steel was the fastest, accompanied by the most rapid precipitation kinetics. The precipitates were (Nb, Ti)C of approximately 50 nm in size, with a mismatch of 14.24% at the matrix/precipitate interface and a screw dislocation angle of 2.07°. The presence of screw dislocation steps may facilitate nucleation of Nb/Ti precipitates, forming semi-coherent interfaces.

Duplex stainless steel (DSS) has been widely used in various applications due to the combination of excellent mechanical properties and corrosion resistance. However, shielded manual arc welding (SMAW) always deteriorates its phase balance and further changes its mechanical properties. Therefore, an appropriate post-weld heat treatment (PWHT) is of the essence to gain the superior performance of the DSS SMAW joint. In this article, the effects of PWHT temperature on the microstructure and residual stress of 2205 DSS SMAW joint were investigated by both experimental and simulation methods. The microstructural characteristics including phase ratio, morphology, grain misorientation, and boundary type were analyzed by the electron backscattered diffraction, while the evolution of residual stress was investigated by a thermal–mechanical coupled finite-element simulation and hole drilling method. The results showed that the residual stress decreased significantly after PWHT, particularly under the higher PWHT temperature. The maximum longitudinal residual stress had dropped by 20.4 and 66.8% at the PWHT temperatures 380 and 1,050°C, which were both far below the yield strength. However, the increase in PWHT temperature promoted the phase proportion imbalance due to the excessive precipitation of intragranular austenite and the formation of low-angle grain boundaries. The fraction of austenite had reached 75.5% when the PWHT temperature was 1,050°C. In order to obtain a reasonable distribution of residual stress and microstructure for the 2205 DSS SMAW joint, it is recommended to perform PWHT at 380°C.

In order to determine the influence of process parameters such as the optimal heating method, heating temperature, and time on the corrosion resistance of zinc iron alloy coatings, and to maximize their corrosion resistance while ensuring coating quality, a study was conducted on the influence of heating process on the corrosion resistance of zinc iron alloy coatings. Prepare coatings on steel-based materials using hot dip method, adjust the auxiliary plating and immersion temperatures, and test the corrosion resistance of coatings at different temperatures. After completing the coating preparation, test the corrosion resistance of the coating under two heating processes, namely, heating furnace and laser, as well as the corrosion morphology and corrosion rate of the coating under different heating temperatures. Calculate the corrosion loss of the coating under different heating durations. The experimental results show that the corrosion resistance of the coating is better when the auxiliary plating and immersion temperatures are 70 and 450°C, respectively. When the laser heating process is selected and the heating temperature does not exceed 450°C, the corrosion resistance of the coating is higher. Once the temperature is exceeded, the corrosion resistance of the coating decreases, and with the increase of heating time, the corrosion resistance of the coating will decrease. When the heating time is 14 min, the mass loss of the coating reaches 0.011 g. And in the electrochemical corrosion test, after soaking for 18 days, the polarization resistance value of the zinc iron alloy coating decreased to 987.8 Ω·cm 2 , achieving complete failure.

Endpoint control stands as a pivotal determinant of steel quality. However, the data derived from the BOF steelmaking process are characterized by high dimension, with intricate nonlinear relationships between variables and diverse working conditions. Traditional dimension reduction does not fully use non-local structural information within manifold shapes. To address these challenges, the article introduces a novel approach termed supervised weighting-based local structure preserving projection. This method dynamically includes label information using sparse representation and constructs weighted submanifolds to mitigate the influence of irrelevant labels. Subsequently, trend match is employed to establish the same distribution datasets for the submanifold. The global and local initial neighborhood maps are then constructed, extracting non-local relations from the submanifold by analyzing manifold curvature. This process eliminates interference from non-nearest-neighbor points on the manifold while preserving the local geometric structure, facilitating adaptive neighborhood parameter change. The proposed method enhances the adaptability of the model to changing working conditions and improves overall performance. The carbon content prediction maintains a controlled error range of within ±0.02%, achieving an accuracy rate of 82.50%. The temperature prediction maintains a controlled error range of within ±10°C, achieving an accuracy rate of 79.00%.

Biopolymer-modified cementitious repair material (CXT) is a composite material designed to enhance the properties of traditional cementitious materials through the incorporation of biopolymers. CXT is formed by blending cement (C) with biopolymers such as xanthan gum (XG) and additives like tartaric acid (TA), which improve the material’s performance characteristics. This study investigates the effects of varying dosages of XG, TA contents, and curing durations on the performance characteristics of CXT. We evaluated key performance indicators, including the flowability, workability, setting time, compressive strength, and shrinkage. The optimal formulation XG 1:2 TA0.6 achieved a maximum compressive strength of 25 N·mm − ² and a flexural strength of 9.4 N·mm − ², with negligible shrinkage. The results showed rapid early strength development, with the material reaching over 77% of its final compressive strength within the first 14 days. These findings highlight the potential of CXT for crack-repair applications, offering improved workability, accelerated setting times, and reduced environmental impact compared to traditional repair materials. This study provides valuable insights for optimizing the formulation of CXT for enhanced performance in real-world applications.

Tungsten trioxide (WO 3 ) films, extensively investigated for their remarkable electrochromic properties, have proven to be highly versatile in numerous applications. However, the challenge of achieving large-scale WO 3 films with substantial dimensions and volumes remains a critical obstacle for industrial-scale production. Among the available techniques, magnetron sputtering stands out as the most efficient and straightforward method for the industrial preparation of WO 3 films. In this comprehensive study, we meticulously explored the impact of various process parameters in magnetron sputtering on the film formation properties. By employing a controlled variable approach, we systematically investigated the influence of gas flow (Ar), sputtering pressure, power, and time. Our meticulous observations revealed that each parameter exerted distinct effects on the intricate film formation process. Careful analysis of the final dataset unequivocally demonstrated that when the sputtering conditions were meticulously optimized, the resulting films exhibited an extraordinary maximum transmittance change of 85% at a specific wavelength of 0.6 μm. Furthermore, these films showcased rapid coloring and bleaching response times, clocking in at an impressive 15 and 20 s, respectively, without any significant degradation even after undergoing 5,000 cycles. These groundbreaking findings provide invaluable insights into the intricate film formation process associated with magnetron-sputtered WO 3 .

Purpose The current work presents a theoretical framework to boost heat transmission in a ternary hybrid nanofluid with homogeneous and heterogeneous reactions in the conical gap between the cone and disk apparatus. Furthermore, the impacts of non-linear thermal radiation on the ternary hybrid nanofluid composed of white graphene, diamond, and titanium dioxide dispersed in water are analyzed. Originality/value The combination of cone and disk systems is crucial for designing efficient heat exchange devices in the field of biomedical science for various purposes. For instance, in medical devices, the cone–disk apparatus is used to study the flow and heat transfer characteristics for better design and functionality. Hence, a sincere attempt has been made to study the impact of homogeneous and heterogeneous reactions on the nanofluid flow between the cone and disk in the presence of non-linear thermal radiation. Design/methodology/approach The mathematical model’s governing equations are partial differential equations (PDEs) which are then transformed into non-linear ordinary differential equations through appropriate similarity transformations. These transformed resultant equations are approximated by the Runge–Kutta–Fehlberg fourth/fifth order (RKF45) technique. The influence of essential aspects on the flow field, heat, and mass transfer rates was analyzed using a graphical representation. Findings The interesting part of this research is to discuss the power of parameters in three cases, namely, (1) rotating cone/disk, (2) rotating cone/stationary disk, and (3) stationary cone/rotating disk. Furthermore, the thermal variation of the fluid is analyzed by an artificial neural network with the help of the Levenberg–Marquardt backpropagation algorithm. The regression analysis, mean square error, and error histogram of the neural network are analyzed using this algorithm. From the graph, it is perceived that the flow field climbed up significantly with an increase in the values of radiation parameters in all cases. Also, it is noticed that temperature upsurges significantly by upward values of solid volume fraction of the nanoparticles ( ϕ \phi ).

A thermodynamic model to predict the stacking fault energy (SFE) of Fe–Mn and Fe–Mn–C austenite steels based on the two-sublattice method has been developed. The calculated Gibbs free energy change, phase transformation temperature, and SFE are basically coincident with the experiment values. The interfacial energy during face center cubic to hexagonal close packed transformation was determined by a parabolic function of Gibbs free energy change in the concerned systems. The interstitial segregation and the resulting SFE in Fe–Mn–C steels have been clearly revealed. The carbon segregated concentration in the stacking faults is in good agreement with the measured value. Low SFE regions were observed to be located at 12 wt% manganese in the Fe–Mn binary system and at 14 wt% manganese in the Fe–Mn–C ternary system, respectively. The carbon- and manganese-dependent SFE maps were consequentially plotted under different temperatures and grain sizes. For the steels with manganese and carbon range between 10–30 and 0–1.2 wt%, the SFE increases monotonously with temperature increasing. The SFE of Fe–Mn–C steels decreases as grain size increases from 1 to 70 μm. However, for the alloys with more coarse-grained structures, the SFE sensitivity to grain size was not obvious.

To examine how micro-textures with distinct structures affect the tribological properties of cemented carbide tool-cutting processes, various micro-textures were meticulously fabricated on YG8 cemented carbide blocks. Subsequently, friction and wear experiments were systematically conducted to examine the microstructure nuances resulting from the diverse structures. The influence of these micro-textures on the friction coefficient of cemented carbide and its underlying factors was comprehensively analyzed. To further investigate the impact of these micro-textures on the cutting force in cemented carbide tools, finite element analysis was conducted. Identical micro-textures used in the tribological experiment were applied to the tool, followed by milling simulations aimed at elucidating the impact of these varied micro-textures on the three-dimensional cutting force exerted by the tool. Empirical investigations and finite element analyses revealed that micro-textures characterized as parallel (parallel to the main cutting edge), perpendicular (perpendicular to the main cutting edge), and a combination of “parallel + perpendicular” significantly enhance the tribological properties of cemented carbide tools. This enhancement is evident in the reduction of both the friction coefficient and cutting force of the tool. Particularly noteworthy is the substantial efficacy of vertical micro-textures in minimizing both the frictional force and cutting force, resulting in a noteworthy reduction of the primary cutting force by more than 60% and a concomitant alleviation of tool feeding force by approximately 25%.

The aim of this study is to optimize fly ash utilization by combining lime, gypsum, and quarry dust in various proportions to develop fly ash lime gypsum quarry dust (FLGQ) bricks with dimensions of 230 mm × 110 mm × 70 mm, as a potential alternative to traditional bricks. The investigation analysed the compressive strength, split tensile strength, water absorption, density, and initial rate of absorption of FLGQ bricks across different mixes. Mix 9 (M 9 ), comprising of 35% fly ash, 10% lime, 25% gypsum, and 30% quarry dust, exhibited a 15% higher compressive strength (7.2 MPa) and 12% higher split tensile strength (0.85 MPa) compared to the superior conventional brick. Water absorption for M 9 was reduced by 18%, enhancing the durability. Prediction models for compressive and split tensile strengths were developed using regression analysis, achieving over 92% accuracy when compared to experimental data at 28 and 56 days. Additionally, a positive correlation was observed between the 14th, 28th, and 56th days results, reinforcing the reliability of predictions in brick compressive strength. These research findings indicate that M 9 is superior and more sustainable alternative to traditional bricks, with significant improvements in key performance metrics.

High-performance ceramics, especially h-BN-based ceramics, are widely used in the metallurgical field. The interface state of h-BN-based ceramic composites, including chemical reactions, molecular diffusion, and interface structure changes, will greatly affect the properties of composite materials. Herein, taking Si 3 N 4 /BN composites as a representative case, their interfacial interactions were investigated by first-principles calculations. First, the structural and electronic properties and elastic modulus of bulk Si 3 N 4 and h-BN were calculated. Then, the interface mismatch relationship and interface models of Si 3 N 4 /BN were studied and established. Finally, the interface bond structure of Si 3 N 4 /BN was analyzed by charge density and state density calculations. The results showed that the band gap of bulk Si 3 N 4 and h-BN was 4.18 and 4.24 eV, respectively. Besides, bulk h-BN exhibited better compression performance and resistance to deformation than Si 3 N 4 based on elastic modulus calculation. Therefore, h-BN was used as a substrate, and when interface mismatch is 1.3%, good matching and bonding at the interface layer can be obtained. Based on this, two interface models of Si 3 N 4 (100)/BN(002) were established, which were named the B-N Si interface and Si-N B interface. The BN/Si 3 N₄ interface exhibited strong van der Waals interactions, and the charge transfer from Si 3 N 4 to h-BN was observed, which indicate that the weak covalent bond also exists in the BN/Si 3 N 4 interface. The low interface energy indicates that the formed interface is relatively stable, which is beneficial for applications requiring high thermal and mechanical stability. This work provides valuable insights into the interfacial interaction between h-BN and Si 3 N 4 and will give a promising theoretical guidance for designing and optimizing h-BN-based ceramic composites.

Iron and steel industry is the pillar industry of the national economy, but it is also the source of highest carbon emission in manufacturing industry. With the proposal of China’s goal of peaking carbon emissions and achieving carbon neutrality, the steel industry urgently requires substantial technological breakthroughs in carbon reduction. About 90% of China’s crude steel production is produced through the blast furnace-basic oxygen furnace process, and blast furnace carbon consumption accounts for more than 70% of steel process carbon consumption. Therefore, blast furnace carbon reduction is the focal point of China’s steel industry’s efforts to mitigate carbon emissions. The hydrogen-rich gas injection to blast furnace and blast furnace with top gas recycling process are effective ways to reduce carbon emissions. However, these approaches still rely heavily on the fossil fuel coal-dominated energy structure. With the rapid development of renewable energy hydrogen production in China, hydrogen-rich oxygen blast furnace technology, which replaces carbon with hydrogen, can significantly reduce carbon emissions from ironmaking at the source. This article establishes a multizone constrained mathematical model for hydrogen-rich oxygen blast furnaces, calculates energy balance based on the constraint conditions of each zone, and systematically studies the influence of hydrogen injection, burden metallization rate on the coke ratio, top gas recycling injection volume, reducing gas composition, and CO 2 emission reduction of hydrogen-rich oxygen blast furnaces. The research results show that at maximum hydrogen injection rate of about 600 N·m 3 H 2 ·t −1 -HM (ton-hot metal), a replacement ratio of about 0.4 kg-coke·(N·m) −3 -H 2 was achieved with about 27% CO in the reduced gas of the shaft, 68% H 2 , 90% burden metallization rate. Coke ratio of the hydrogen-rich oxygen blast furnace is reduced to 203 kg and the CO 2 emission is reduced to 501 kg·t −1 -HM, 55% lower than that without hydrogen injection with a very significant CO 2 reduction at the source.

Due to the high-dimensional nonlinear nature of the BOF steelmaking production process data, although the ability of deep learning to extract abstract information is more prominent, it faces the challenge of low correlation between the extracted features and labels, and the static model cannot be applied to the forecasting requirements under changing working conditions. In order to enable deep learning to cope with these problems and maintain good prediction performance, this chapter proposes a Deep Belief Network (DBN) feature extraction model based on dense connectivity of key features. First, the key features are selected by feature importance judgment and redundancy judgment, and the selected key features are passed layer-by-layer through a densely connected structure. Second, a deep feature extraction network is formed by stacking layers to improve the feature extraction capability of the network. Finally, a Just-in-time learning (JITL) method is proposed to reduce the high-dimensional steelmaking data of the BOF while preserving the data structure by using the stream learning dimensionality reduction method to improve the accuracy of the metrics in the JITL process, so that the online fine-tuned model can be applied to the forecasting requirements under different working conditions. According to the actual BOF steel production process data, the prediction accuracy of the terminal carbon content reached 82.0% within the error range of ±0.02%, and the prediction accuracy of the temperature reached 80.0% within the error range of ±10°C.

This study investigates the effects of tempering temperature on the microstructure and mechanical properties of Q125 grade shale gas casing steel using experimental methods such as optical microscopy, scanning electron microscopy, and transmission electron microscopy. The results show that during the tempering process at 500–560°C, the morphology of the quenched laths gradually disappeared and the microstructure gradually recovered. Carbides precipitate from lamellar structures and gradually transform into short rod-like and fine dispersed spherical shapes, mainly distributed along the prior austenite grain boundaries (PAGB) and lath boundaries, accompanied by a decrease in dislocation density. At a tempering temperature of 530°C, the steel exhibited optimum overall mechanical properties, with a tensile strength of 961 MPa, yield strength of 921 MPa, and impact energy of 138.9 J. Within the tempering range of 500–560°C, the macroscopic tensile fracture surfaces exhibited obvious necking and delamination, with a microscopic morphology characterized by dimples accompanied by secondary cracks and tearing ridges. Both the initiation and propagation zones of the impact fracture surfaces exhibited dimple features, indicating good ductility. Microcracks and micropores observed in the longitudinal section of the tensile fracture are distributed along the PAGB or lath boundaries, with carbides located at the interfaces, reducing the interfacial energy.

The rapid development of modern aerospace and energy industries requires increasingly high service performance of metallic materials. Laves phase intermetallic compounds with the chemical formula AB 2 -type have attracted much attention due to their high melting point, excellent high-temperature strength, and oxidation resistance, and are regarded as one of the promising candidates for a new generation of high-temperature structural applications. Although it can be identified that Laves phase alloy research has been an active research field in the last 20 years in terms of the trend of literature volume growth, there is still a lack of systematic descriptions and comprehensive overviews of the latest frontiers and hotspots in the field. In this article, a quantitative and visual knowledge mapping of the articles published in the field of Laves phase research in the last 20 years has been carried out based on the bibliometric analysis methodology of Cite Space software. Quantitative analysis of high-frequency keywords to understand the basic development of Laves phase and the evolution of the main research hotspots in each period of time identified the hotspots of common concern seven themes: Laves phase, electronic structure, precipitation, Inconel 718 alloy, phase diagram, high-entropy alloys, and TiAl-based alloys. The analysis of the emergent keywords shows that electronic structure, high-entropy alloys, total energy calculations, and laser cladding can represent the research frontiers of Laves phases. This study provides systematic and valuable reference information to gain insight into the current state of Laves phase research and the evolution of the theme, which will be useful for further research.

Basic oxygen furnace (BOF) steelmaking is a widely used method for steelmaking production, and the bath stirring has a significant influence on dynamics of bath flow and mixing. Therefore, the effect of bottom gas flowrate, nozzle number and configuration, and bottom gas distribution mode on bath stirring are summarized in this study. Reasonable matching of bottom gas flowrate, nozzle number and configuration, as well as intensive study on the coupling effect of gas flowrate gradient and exchange frequency on non-uniform stirring would receive more and more attention in the coming years. With wide concern on the low-carbon and high-efficient production for BOF steelmaking, as a kind of recyclable iron-containing resource, the rapid melting and reasonable utilization of scrap in converter bath were emphasized in recent works, which could be promoted with high-efficient bottom stirring. The effect of bottom stirring on heat and mass transfer during scrap melting process was reviewed in this work, and the influence mechanism of bottom stirring on coupled heat and mass transfer should be further investigated. In addition, an overview of recently published physical and numerical simulation describing the bottom stirring and its effect on scrap melting would provide an outlook for future work.

Nb–Ti–Al base alloy is an important structural material with low density and high temperature. However, as with other niobium alloys, the weak oxidation resistance is the bottleneck of its engineering application. Surface coating technology is considered an ideal method to solve the oxidation resistance of Nb–Ti–Al-based alloys. In this article, the progress of research on high-temperature antioxidation silicide coatings on Nb–Ti–Al alloy in recent years is reviewed. The microstructure, phase composition, and oxidation properties of different silicide coatings are analyzed. The failure mechanism and applications of Nb–Ti–Al-based alloy silicide coating are summarized. The existing problems and future development of Nb–Ti–Al-based alloy silicide coatings are analyzed and prospected.

Autoclaved aerated concrete (AAC) has been extensively studied and applied in the past decades because of its excellent thermal insulation and acoustic performance, energy efficiency, and outstanding structural performance. To investigate the deterioration characteristics of AAC under high temperatures, the physico-mechanical properties of AAC at different temperatures were tested by mass loss, wave velocity, and compressive tests, and the deterioration mechanism was discussed by X-ray diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) tests. The results showed that after exposure to elevated temperatures, the parameters of apparent form, mass loss, wave velocity, and compressive strength underwent remarkable conversions. It was observed that the ultrasonic behavior of AAC was affected at high temperatures as it increased at 100°C and decreased beyond 100°C. In addition, the compressive strength exhibited a two-stage transformation, slightly increased from ambient temperature to 300°C, and exhibited a rapid reduction beyond 300°C. At 900°C, the specimen lost its strength. By XRD, TGA, and SEM, it was confirmed that a series of physicochemical changes in AAC, such as the water escape and evaporation, decomposition of calcium silicate hydrate and calcium carbonate, and structural damage, were the primary reasons for the deterioration of the physical and mechanical properties at elevated temperatures.

Austenitic heat-resistance steel is widely employed in ultra-supercritical power generation because of its superior performance. This article reports the evaluation of creep damage of a typical Super304H austenitic heat-resistance steel by using the Kikuchi pattern parameters, such as band contrast (BC), mean angular deviation (MAD), and band slope (BS). It was found that the mean BC and MAD values did not show a monotonic changing trend and then an in-depth research that distinguished grain boundary and grain interior regions of Super304H steel was studied, respectively. The results manifested that, with the increase of creep time, both the mean BC and BS values showed a monotonic decreasing trend, while the MAD did not. Besides, compared with the BC, the change amplitude of BS was larger. The results indicate that the BS could be a useful indicator, which can be utilized to evaluate the creep degree of Super304H steel in a quantitative way.

In the present work, aluminium alloy-based composites were developed for automobile applications. Aluminium-based functionally graded material (FGM) was developed by adding 2.5, 5 and 7.5 wt% of nanoparticles of alumina. The composites were made using gravity casting in an open hearth furnace with the surface temperature of FGM maintained at 750, 850 and 1,000°C. The microstructure of the samples was studied using scanning electron microscopy and particle distribution. The particle distribution was higher at the bottom in all compositions, which can be attributed to more solidification time. As the wt% of the Al 2 O 3 increased, the volume fraction of particles also increased from the top surface to the bottom surface of the samples. After adding 7.5 wt% of Al 2 O 3 and heating up to 1,000°C led to the grain refinement of the alloy. The increase in hardness from the top surface to the bottom surface of the sample verified the development of FGM. Due to increase in the solidification temperature, better reinforcement was observed in the developed FGM.

Due to its low density, magnesium is recognized as a lighter metal and it is favorable for frequent use in industries. It is used in aerospace, biomedical, automotive, and other industrial applications. Magnesium is a promising element that is vital for reducing emissions, improving efficiency, protecting the environment, and enhancing the machine economy. This study analyzes the influence of various cutting environments and parameters on the turning operation of magnesium base alloy (AZ91D). Aluminum 9% and Zinc 1% is the main constituent of AZ91D. The machining process was accomplished using dry, minimum quantity lubrication (MQL), and nano minimum quantity lubrication (NMQL) environments based on their influence on surface roughness (SR) and temperature. Under certain circumstances, it was observed that SR decreases with the increase in the cutting velocity ( V c ), feed rate, and depth of cut. During cutting of AZ91D in dry conditions, it is preferred to use a moderate speed. Higher temperature was recorded during dry conditions which can significantly reduce the life span of the tool. MQL and NMQL have reduced the cutting temperature by a margin of 25–40% compared to dry machining, thus improving tool life. NMQL has shown decent cooling results compared to other cooling systems.

Controlling defects such as deformation in the weld joint and the residual or superfluous stresses due to tungsten inert gas (TIG) welding or arc welding is a major concern for many industries like aeronautical, automobiles, nuclear or atomic power plants, crude oil or fossil fuel industries where pipes are in use and circumferential welding is done. Arc welding is a metal joining process, and TIG welding is applied to many industrial sectors that require high-quality welding. Simulation has been done on single-pass TIG welding on the Flange pipe of SS316 to evaluate transient temperature, residual stresses, and distortion. First, a 3D model is developed and assembled in SolidWorks. Second, in an MSC Patran, preprocessing of the FE model is done. Finally, in MSC Marc, thermal and mechanical simulation is performed. Based on this simulation, the accuracy of welding of the flange–butt joint made of SS316 is validated. In this study, the information regarding simulation of temperature dispensation and residual or superfluous stresses is done on the flange–butt joint, and it found the stresses are compressive at the weld bead area, and along the transverse direction, stresses changed to the tensile. The experimental data show that the steep curve at 0.00 mm represents a maximum temperature near the weld path at approximately 2,352°C, and the slant curve shows the far away points from the weld path. Comparing it with FE analysis, the maximum temperature attained was around 2,539°C. An approximate deviation of 7.365% was observed. The results of the study will provide experimental and simulation analyses for the welding of pipes of stainless steel for the transportation of oil and gases in the petroleum industries.

In recent years, electric vehicles (EVs) have grown in popularity as a viable way to reduce greenhouse gas emissions by replacing conventional vehicles. The need for EV batteries is steadily increasing. An essential and expensive part of electric transportation is the battery. The operating temperature of the lithium-ion (Li-ion) battery significantly impacts the performance of the EV battery pack. Battery packs undergo temperature fluctuations during the charging and discharging procedures due to internal heat generation, necessitating an examination of the temperature distribution of the battery pack. The geometrical spacing between cells is considered larger and identical and is kept open on two sides for free air circulation. A novel battery thermal management system (BTMS) design is required to effectively dissipate heat from the prismatic battery pack module. The electro-thermal behaviour of the prismatic Li-ion battery pack module was investigated based on the high charge/discharge rate. This study presents the development of a three-dimensional free open-source OpenFOAM computational fluid dynamics model for prismatic cell battery packs that simulates heat generation, air flow field, and temperature distribution across the width and depth of the battery pack module. The prismatic battery pack simulation results are compared with the experimental and simulation results of the cylindrical battery pack. It was also revealed that prismatic cells generate more heat on the backside, requiring battery packs to have increased cooling and space between individual cells to ensure sufficient air circulation for cooling and gas removal. The BTMS is improved by designing with increased space among the prismatic battery cells as compared with the conventional prismatic cell battery pack design.

The automotive and aerospace sectors have a strong demand for Nitinol alloy machined parts; therefore, optimizing machining parameters is essential to achieving better process performance results in terms of cost and product quality. In general, the process variables that influence machining include feed ( f ), depth of cut ( t ), and spindle speed ( S ). Material removal rate (MRR), tool wear (TW), and surface roughness (Ra) are pertinent output performance indicators. Analysis of variance has been performed to assess the effect of process variables on the aforesaid output performance. It has been found that feed has a significant effect on MRR and surface roughness with a contribution of 50.65 and 33.62%, respectively, whereas spindle speed has a major contribution on TW with a contribution of 51.9%. This study assesses how well the Nitinol 56 machining process works overall. In this work, the Taguchi method has been used to determine the effect of aforesaid process variables on the output performance indices. To satisfy previously stated conflicting performance indices, a variety of multi-attribute decision-making approaches were used, such as utility, TOPSIS, and grey, to determine the optimal process variables. The optimal process variable combination has been achieved as f = 0.133 mm·rev −1 , d = 0.06, and S = 835 RPM. This combination has been achieved using all methods.

The present study aims to explore experimental investigations and numerical simulations for temperature distributions at heat-affected zones within SA 387-Gr.11-Cl.2 steel during the submerged arc welding (SAW) process. Experimental endeavors entailed welding steel plates under controlled conditions, precisely measuring temperatures at key locations by thermocouples. A special program based on 3D Goldak’s double ellipsoidal model was developed in ANSYS Parametric Design Language for moving heat source calculations in the finite-element analysis (FEA). For welding an 8 mm thick plate with one pass, the suitable parameters were found to be 600 A current, 31 V voltage, and 10 mm·s −1 welding speed. The experimental cooling periods were found to be slower than predicted by FEA. When temperature distributions were compared between experimental and FEA results, an average variation of 1.88% at peak temperatures and 11.8% at completion time was observed. The results showed the temperature distribution at various time steps, illustrating the transient nature of the welding process. The results highlight the capacity of the FEA model to predict temperature profiles during SAW accurately, presenting a potent tool for optimizing welding parameters without extensive trial and error.

Plasma arc cutting (PAC) has emerged as a versatile and efficient method for the precision cutting of various materials, including commercial-grade aluminium plates. The optimization of process parameters is crucial for achieving high-quality cuts, minimizing material wastage, and enhancing overall productivity. This study aims to systematically investigate and optimize the key process parameters in PAC of commercial-grade aluminium plates. The experimental design involves the manipulation of parameters such as arc current, gas pressure, and workpiece thickness. A Design of Experiments approach, specifically Taguchi’s orthogonal array, is employed to efficiently explore the parameter space and identify the optimal combination of settings. The response variables considered for optimization include minimum surface roughness, minimum burr height, and maximum material removal rate (MRR). Analysis of variance is performed to get the percentage influence of each process parameter on the performance characteristic. The results obtained from the optimization process are expected to provide valuable insights into enhancing the efficiency and precision of PAC for commercial-grade aluminium plates. Arc current is found to be the most significant parameter in altering the surface roughness. The thickness of the material is the most significant parameter in altering burr height. None of the parameters is found to be significant in altering the MRR from Analysis of Variance analysis. From signal-to-noise ratio analysis and average performance graph, the optimum combination of processes in altering the bur height and MRR are found as arc current at 50 amp, the gas pressure at 5.4 bar, and the thickness of the workpiece at 6 mm.

This study reports that a fuzzy logic-based grey system using Taguchi’s method provides a reliable approach to the prediction of friction stir welding (FSW), which is capable of improving the multi-response performance of butt welds. Using the grey relational database, a fuzzy logic analysis is carried out. Analysis of variance is used to determine the effect of parameters of multi-response behaviors on butt welds. Meanwhile, multiple responses for multivariables are simultaneously optimized. The experimental results show that the fuzzy logic-based grey system using Taguchi’s design reveals the optimal settings of the parameters, which improves the whole properties by more than 28.04%, while the individual properties, such as tensile strength by 13.35%, bending strength by 1.91%, impact strength by 1.05%, and hardness by 0.26%, when compared with the best test in orthogonal arrays. Based on experimental validation tests, excellent agreement between model predictions and experimental results is shown. Notably, the intelligent method proposed is applied to butt welds, and the results of the implementation of fuzzy logic based grey system using Taguchi’s design proved its feasibility and effectiveness with respect to the improvement of the mechanical properties of FSW.

In the present research work, the influence of heat input rates on microstructures, hot tensile properties, and weld surface hardness number of Super Duplex Stainless Steel 2507 super duplex steels and austenitic steels 316L plates were investigated. Pulsed current and constant current modes were used in Tungsten Inert Gas (TIG) welding to join the dissimilar metals using ER2205 as filler. Microstructural studies were revealed at different zones of pulsed and constant current TIG weldments using optical microscopy. The tensile test was conducted at two different temperature conditions (i.e., 27 and 350°C) to investigate the strength of dissimilar weldments. Hardness measurements were made on the weld surface along the transverse direction using Vicker’s hardness tester. The microstructures revealed the formation of inter-granular austenite at the fusion zone with grain boundaries with austenite structures. Due to the constant heat input, a significant microstructural development with high austenite fractions was observed in constant current (CC)-TIG weldment. In comparison to CC-TIG weldments (UTS at 27°C = 600 MPa UTS at 350°C = 456 MPa), higher tensile characteristics were noted in Pulsed Current (PC)-TIG weldments (UTS at 27°C = 695 MPa UTS at 350°C = 475 MPa). The UTS of PC-TIG weldment is improved by 15.8% when compared to CC-TIG weldment due to the controlled heat input rates. PC-TIG weldments exhibited improved hardness numbers in various zones with smaller HAZ widths than CC-TIG weldments.

The need for sheet metal forming using highly resistant materials such as titanium alloys and stainless steel has increased recently. These materials possess elevated mean flow stress values, which make them difficult to draw at room temperature. To achieve a homogeneous distribution of strain in the stretched component, reduce the load required for plastic deformation, and greatly improve material formability, hot forming is helpful. The goal of the current study is to conduct stretch-forming experiments to investigate the forming characteristics of Austenitic material Stainless Steel (ASS) 304 at Hot working temperatures. Stretch forming experiments have been conducted on the Servo electrical sheet press test machine at 650 and 800°C. The formability has been estimated by constructing a Fracture forming diagram (FFLD), limiting the height of the dome (LDH) and the distribution of the strain of stretched cups. It has been discovered that the limit of forming bounds rises with the temperature reaching 800°C, while the DSA effect causes the necking region – the area between the safe and fracture limits ‒ to decrease with additional temperature rise from 800 to 900°C. Within the experimental limitations, it has been considered that the Hot forming of ASS 304 at 650°C gives the highest strain forming limits with a uniform strain distribution in the stretched cups. From the Formability limit diagram, dome height, and strain distribution, it can be observed that ASS 304 has good limiting strain up to 800°C with lower load application.

One of the most common characteristics of metallic alloys is work hardening, which is most beneficial as it is the primary reason for the alloys’ tenacity to withstand loading even in the presence of internal flaws or geometrical errors. Thus, the work hardening coefficient gives the maximum amount of homogeneous plastic deformation in tensile straining. Thus, complex-forming operations are facilitated by a high coefficient without experiencing premature failure. Naturally, work hardening has a significant impact on the mechanical energy required to shape a material by plastic deformation, such as rolling, forming, etc. The quantity of energy that the material stores during plastic deformation is also managed by work hardening. As a result, it significantly influences how the metal behaves when it is subsequently softened during annealing. Finally, the hardening capacity and durability of the work hardened state are significant practical challenges because many high-volume stretch formed components are directly used. Typically, the current study begins, at homologous temperatures above 0.4 times melting point, with a description of work hardening at 700, 800, and 900°C temperatures in three different orientations with respect to rolling direction R 0 , R 45 , and R 90 and 10 −1 −10 −3 s −1 strain rates, where thermally triggered processes exhibit a prominent role in work hardening. Three stages of behavior were identified by analyzing the tensile work hardening of ASS 304 steel. Dynamic strain aging is the cause of the anomalous fluctuation in the work hardening rate that is seen in hot working temperatures. X-ray diffraction examination is conducted to introspect any phase changes occurring in hot working regions improving plasticity of ASS 304.

In the pursuit of advancing turbine blade materials, refractory high-entropy alloys (RHEAs) have emerged as promising candidates, offering superior performance at elevated temperatures compared to conventional superalloys. With the plateauing of melting temperatures in Ni-based superalloys, the demand for innovative material systems capable of substantial performance enhancements in turbines has increased. The expansive compositional space of high-entropy alloys (HEAs) presents a rich yet underexplored realm, particularly concerning the intricate phase equilibria pivotal for alloy stability at high temperatures. This research purpose is to elucidate the phase formation dynamics within the W–Re–Ni–Co–Mo HEA system across varying atomic percentages of each constituent element. Employing two-dimensional mapping methodology for correlating atomic size difference and enthalpy mix parameters, enabling the differentiation between intermetallic (IM) phase and single-phase formations in the non-equimolar W–Re–Ni–Co–Mo system across numerous atomic percentages of each element. Major findings indicate distinct phase formations based on elemental compositions, with elevated nickel and rhenium percentages favouring single-phase solid solution (SPSS) structures, while diminished concentrations yield alternative configurations such as (IM + SPSS). Similarly, variations in tungsten and molybdenum concentrations influence phase stability. The ability to assess phases for diverse atomic percentages of elements in the W–Re–Ni–Co–Mo system will facilitate to analyse HEA systems for high-temperature turbine blades.

The geometry and sharpness of the cutting tool have a substantial impact on the final product’s quality. The geometry of cutting edges is altered throughout the machining process, and wear causes the cutting edge to become dull. This causes increased surface roughness, dimensional inaccuracy, cutting forces, chatter, and vibration. The present research focuses on tool wear (Vb) under dry machining conditions during ball end milling of Ti6Al4V alloy. The experiments are conducted using the full factorial design of experiments with three parameters, viz. feed ( f ), depth of cut ( A t ), and rotational speed ( S ) at three levels. A total of 27 experiments are conducted with one replicate. Artificial neural network (ANN) with 3-18-2-1 architecture is used for the study of the tool wear monitoring (TWM) system. Results revealed that the TWM model is highly adequate, with R 2 = 99.89% and R 2 adj = 99.65%. The percentage contribution of A t is the highest, amounting to 80.6%, followed by feed of 12.46%. The rotational speed has the least contribution to tool wear, amounting to 1.5%. From ANN modeling, R 2 value testing is found to be 0.9974, which is close to unity and reveals that the trained model excellently fitted the testing data. The model accuracy is also found to be 96.46%.

With its exceptional qualities, Incoloy 825 is highly valued in a range of industries, including nuclear power plants, petrochemical plants, and chemical industries. Nevertheless, the unique combination of these properties presents a formidable challenge when it comes to machining Incoloy 825. Its low heat conductivity, rapid strain hardening, strong chemical affinity, and the presence of hard and abrasive particles in its microstructure all contribute to the difficulty. The objective of this study is to examine important factors related to the machinability of Incoloy 825. To achieve this, a hybrid tool called entropy coupled with MOORA will be used to determine the optimal cutting conditions. In order to achieve this, three specific input parameters were chosen: the spindle speed, feed rate, and depth of cut. Meanwhile, the major outcomes taken into account were the cutting force, cutting temperature, material removal rate, roughness of the machined surface, and flank wear. The experiments were conducted using Taguchi’s L 27 orthogonal array, following the principles of experimental design. The findings indicate that the proposed hybrid approach is capable of accurately determining the best combination of parameters for cutting the chosen work material and can be employed in structural applications. For turning Incoloy 825, the optimal parametric setting was determined to be a spindle speed of 1,285 rpm, a feed rate of 0.0625 mm·rev −1 , and a depth of cut of 0.3 mm.

In the current scenario, a green product is designed to have a minimal impact on the environment as it is made from recycled materials. In the highly energy-intensive industry, green production has a significant influence on business sustainability. The intelligent environment around us created an unavoidable problem, because of the uncontrolled growth in waste materials like plastic and electrical trash. Both seriously endanger the environment, wildlife, and human health, trash has an impact on societal structures and financial systems in future generations. Industrial and domestic plastic wastes, which are dumped in landfills or the environment, are mostly made of polyethylene (PE) polymers. These wastes’ polymeric nature makes them difficult for microorganisms to degrade. Incorporating biological and chemical processes together is facilitated by pyrolysis and the biodegradation of alkenes to achieve the maximum biodegradation of PE plastics, as proposed in this study, to reduce plastic waste. This research outcome demonstrates that the Waste plastic recycling plant dataset is taken to show the decomposition of high-density PE plastic to simpler alkene with microbial-assisted degradation of alkene to biomass through bacterial communities. Communities of microbes from three different environments inoculating at three nutrient levels are monitored for their ability to degrade model alkenes (with several carbon atoms) within 5 days. There is Plenty of evidence indicating that the nutritional content significantly influences the rates at which hydrocarbons are broken down. These findings imply that the microorganisms required for alkene breakdown are present in a wide range of ambient microbial communities and are significantly chosen under optimized environments such as nutrient enrichment.

This research comprehensively explores the synthesis of Co–Ni–TiO 2 coatings employing a hybrid methodology that integrates sol-enhanced and pulse current electrodeposition techniques. The investigation examined the surface morphology and intrinsic properties of Co–Ni–TiO 2 coatings, revealing the significant influence of pulse duty cycle variations on the characteristics of coatings. A detailed analysis indicates that a pulse duty cycle of 0.4 optimized the coating’s performance, offering superior attributes compared to other duty cycle settings. The study elucidates that lower duty cycles foster hydrogen evolution reactions on the cathode surface, culminating in the formation of a porous, needle-like coating structure. Conversely, higher duty cycles are found to mitigate the effects of material replenishment, thereby affecting the coating’s quality and performance. The findings of this investigation not only shed light on the critical relationship between the pulse duty cycle and the properties of Co–Ni–TiO 2 coatings but also lay a foundational framework for the further refinement and optimization of these coatings for advanced applications.

On a Gleeble-3800 thermal simulator, the hot deformation behavior of Cr–Mo–Ni–V steel was studied, with the designed deformation temperature varying from 900 to 1,200°C and the strain rate in the range of 0.01–10 s −1 . It was observed that as the strain rate was increased and the hot working temperature was reduced, the flow stress of the experimental steel increased. The study also evaluated the safe parameters for deformation of the Cr–Mo–Ni–V steel in the hot working process, based on the established processing maps. It was found that the deformation temperature window varying from 1,050 to 1,150°C and the reasonable strain rate in the range of 0.01–1 s −1 are beneficial to the hot deformation of the steel. In this research, the effect of processing parameters of the hot working process on the microstructure evolution of the banded structure was also investigated. According to the research result, the banded structure in the steel remained visible under the conditions of a strain rate of 10 s −1 and the hot working temperature in the range of 900–1,200°C. However, it should be noted that the banded structure in the steel then gradually disappeared when the hot working temperature was increased to 1,200°C.

Different combinations of normalizing and tempering were carried out to optimize the microstructure and enhance the high-temperature mechanical properties of HRB400FR fire-resistant steel bars. The results showed that with the increasing of the tempering temperature from 400 to 600°C, the steel bar’s hardness decreases linearly, mainly due to the formation of quasi-polygon ferrite and granular bainite. Besides, the reduced width and the dissolution of the lath bainite also undermine the performance of the tempered steel bars. The highest Vickers hardness of 380 HV is achieved when the steel is normalized at 950°C and then tempered at 400°C, mainly due to precipitation strengthening and bainite strengthening. The hardness of the test steel tempered at 600°C gives the lowest value, only 230 HV since the least amount of bainite is obtained. When the tempering temperature reaches 650°C, the hardness rises to 260 HV due to the formation of the lath bainite. The emergence of needle bainite generally reduces the matrix grain size, and the appearance of lath martensite refines the precipitated carbides.

As a thin-walled complex structure, the manufacturing of Al-based diesel engine diaphragms involves casting and heat treatment. Residual stress is introduced during the uneven temperature field in casting and heat treatment, as well as the plastic deformation and cutting heat during mechanical processing. This research investigates the evolution and accumulation models of residual stress in casting and heat treatment for Al-based diesel engine diaphragms using ProCAST and ABAQUS software, combining with the experimental tests. To mitigate residual stress, the optimal parameter combination for casting temperature, knockout temperature, and mold preheating temperature in casting process is explored. The results indicate that the knockout temperature has the most significant influence on casting residual stress, and mold preheating is beneficial for reducing residual stress. Despite improvements, some internal stress concentration areas persist on the knockout casting surface. Furthermore, T6 heat treatment proves to be effective in eliminating more than 50% of the residual stress.

The impact resistance of the steel fiber reinforced concrete (SFRC) beams after exposure to fire was studied. The SFRC beams were subjected to open flame for 120 min. After cooling to the ambient temperature, the drop-weight impact tests were conducted on the SFRC specimens. The influence of the steel fiber type and fire temperature on the impact-resistant properties was examined. The temperature time history, force time history, and reaction force-deflection curve were obtained. The peak force is discussed and the energy absorption is calculated. The results showed that the influence of steel fiber type on the impact resistance of SFRC was negligible, while the impact resistance and ductility of SFRC decreased significantly after exposure to fire. Compared with the partial fracture of the specimen at room temperature, the specimen after fire showed a more complete fracture under impact load, indicating a larger deflection and more pullout of steel fibers. This means that more friction is needed during the damage process, resulting a higher energy absorption.

The bonding behaviour between steel fibre and concrete matrix at elevated temperature and various loading rates was investigated. Pullout tests were carried out on the hooked-end steel fibre reinforced concrete specimen and the effects of elevated temperatures (200, 400, and 600°C) and loading rates (2, 10, and 50 mm·min −1 ) were considered. The ultimate bond strength and energy absorption were discussed to evaluate the bonding behaviour. The results revealed that the bonding behaviour for the case of 400°C performed best, while the bonding behaviour for the case of 600°C performed the worst. At room temperature, the bonding behaviour is similar to the case of 200°C. In addition, the higher the loading rate, the greater the fluctuation of the bond slip curve of the specimen, and higher ultimate pullout load and energy absorption may be observed.

To investigate the diffusion of sulfate ions in coral seawater concrete under the mechanism of the wetting–drying cycle of sulfate solution, the concentration of sulfate ions in coral concrete at different depths under different cycling cycles was tested in this experiment. Finite-element numerical simulations were then carried out using COMSOL software. The results showed that the sulfate ion concentration in the concrete at the same depth increased steadily with time, and the erosion depth also increased. The numerical simulations successfully reproduced the diffusion of sulfate ions in coral seawater concrete under the mechanism of the wetting–drying cycle of sulfate solutions.

The hot compression behavior of 316LN stainless steel for the supporting system in a magnet confinement fusion reactor was isothermally compressed at 1,050℃ and 0.1 s −1 . Electron backscatter diffraction was used to study the microstructure and texture evolution during the deformation process. The results showed that the necklace structure is eventually formed by increasing compression strain due to dynamic recrystallization (DRX). The proportion of low-angle grain boundaries first increases and then decreases. The dominant DRX mechanism of 316LN is discontinuous DRX, which is characterized by the grain boundary bulging. Besides, twinning is found to be induced to accommodate the plastic strain, helping the development of DRX.

A Kovar alloy composite wire inlaid with copper core was developed through hot isostatic pressing sintering and subsequent multi-pass drawing. The interface between the Kovar alloy and copper was revealed, and the physical properties of the composite wire were investigated. The results show that the Kovar alloy and copper diffuse mutually during the forming process, producing a stable metallurgical bond. When the diameter of the wire is 2.8 mm, a diffusion layer of about 16.5 μm was found at the interface. The concentration of the diffused element had a gradient distribution from the interface to both sides. Combining the excellent properties of Kovar alloy and copper, the composite wire has comprehensive physical properties. The electrical and thermal conductivities are 9.38 × 10 6 S·m −1 and 72.2 W·m −1 ·K −1 , respectively. The composite wire has a low coefficient of thermal expansion, and the average coefficient of thermal expansion is lower than 6.36 × 10 −6 ℃ −1 in the temperature range of 25–450°C.

High nitrogen stainless steel has wide application prospects in many fields such as aerospace, petrochemical industry, marine engineering, energy, and military. Nitrogen is added as an alloying element to replace the more expensive element, nickel, thereby reducing the cost. Since nitrogen serves as an austenite stabilizer and has a higher nickel equivalent, it can improve the corrosion resistance and other mechanical properties of the alloy, yet it could also cause porosity and cracks. As the most upstream process of material processing, the solidification process largely determines the structure and performance of the product. High temperature confocal microscope can provide in-situ observations of phase transformation in metals and alloys. Thermodynamic calculations and other research articles show that the solidification of high nitrogen stainless steel usually involves multiple phases, δ-ferrite, γ-austenite, and liquid (L). Present research utilizes a unique concentric solidification technique to manually create a solid/liquid interface for studying the coexistence of multi-phase. It was found that during the solidification process of a high nitrogen stainless steel, the γ grows along the L/δ interface (L + δ → γ), and then, the pre-formed γ through peritectic reaction grows into δ and L phase. This two-step solidification mode is a typical peritectic solidification. The intervention of N makes the solidification process of high nitrogen stainless steel extremely complicated, because N is a strong γ stabilizer, and its content dramatically affects the formation of the primary phase. The rarely reported peritectic solidification in high nitrogen stainless steel was observed, and these findings could help improve the continuous casting process of high N alloys.

Submerged arc welding method was used to weld 40 mm thickness Q690qE high-strength steel to study the influence of welding heat input on the microstructure and properties of Q690qE joints. The result shows that welded seam with full penetration and no obvious defects is achieved in the Q690qE joints when the welding heat input ranges from 22.5 to 33.6 kJ·cm −1 . The microstructure of welded seam mainly consists of acicular ferrite and granular bainite (GB), the microstructure in coarse-grain zone is GB and lath martensite. As the welding heat input increases, the microstructure of coarse-grain zone becomes lath bainite (LB) and a small amount of GB and the microhardness decreases. The microstructure of the fine-grained area mainly includes ferrite, GB, and a small quantity of LB. In terms of impact toughness, with the heat input increasing, the impact toughness at the center of welded seam and the heat-affected zone decreases subsequently. The tensile test results of the welded joints show that the fracture always occurs in the parent material area, with a tensile strength higher than 864 MPa, and the elongation after fracture decreases as the heat input increases.

In this article, a hollow flange beam (ARHFB) composed of self-piercing rivet (SPR) and galvanized steel sheet was proposed, and the process parameters and mechanical properties of SPR connection technology for Q235 galvanized steel sheet were studied. Through the Taguchi method tests, the thickness of the joint section and the interlocking depth were measured. The tensile and shear tests were carried out, respectively, to obtain the corresponding quasi-static curves. In the four-point bending experiment of ARHFB, the effects of connection including welding, self-tapping screw, and SPR on the bending resistance of ARHFB were compared. The bearing capacity of ARHFB with self-tapping screws is significantly lower than that of welded ARHFB, and the 100 mm spacing SPR connection has strong substitutability for welding.

The present study explores the structural, phase stability, mechanical, and electrical properties of Mg–Ho intermetallic phases, namely Mg 24 Ho 5 , Mg 2 Ho, and MgHo. The investigation is conducted using the first-principles plane-wave pseudopotential method within the framework of density functional theory, as implemented in the Vienna Ab initio Simulation Package. The primary objective of this research is to illuminate the phase stability and mechanical behavior of these compounds, which are of paramount importance for their potential applications in magnesium alloys. The study determines the formation enthalpy (Δ H ) and elastic constants ( C ij ) for each intermetallic phase and calculates the elastic moduli of the corresponding polycrystalline materials. The findings of this study reveal that the MgHo phase exhibits the highest absolute value of formation enthalpy (Δ H = −8.01 kJ·mol −1 ), indicating its superior stability among the three investigated intermetallic phases. As the concentration of Ho in Mg increases, the G / B ratio for the phases decreases from 1.02 to 0.60 (>0.57), suggesting that the intermetallic phases are stable, albeit brittle. The elastic anisotropy index ( A U ), derived from the elastic constants ( C ij ), follows an ascending order of Mg 24 Ho 5 , Mg 2 Ho, and MgHo, signifying that MgHo possesses the most favorable elastic anisotropy among the studied phases.

Utilizing the conventional approach, the positive temperature coefficient of resistivity (PTCR) performance of lead-free ceramics based on (1 − x %)(Ba 1− y Y y )(Ti 1.011− z Nb 0.001 Mn z )O 3 − x %(Bi 0.5 Na 0.5 )TiO 3 (BBNT x ) was examined. The BBNT x ceramics were prepared using the double donor dopant under firing at 1,350°C for 120 min in the air. The findings exhibited that when the Y 3+ concentration elevates, the room-temperature resistivity of 99%(Ba 1− y Y y )(Ti 1.011− z Nb 0.001 Mn z )O 3 – 1%(Bi 0.5 Na 0.5 )TiO 3 (BBNT1) samples initially falls and subsequently elevates. Moreover, the critical content of the samples is 0.15 mol%. Furthermore, the samples’ resistance jumping ratio can be effectively improved by adding Mn 2+ . The manganese dioxide level of 0.05 mol% yields the greatest resistance-jumping ratio. Besides, the impact of (Bi 0.5 Na 0.5 )TiO 3 (BNT) concentration on ceramics’ Curie temperature was examined in the work. Therefore, good free-lead PTCR thermistors were successfully prepared by doping 3% BNT, with a resistance jump of 4.1 magnitude.

Significance Studying the flow of ternary nanofluids [Ag, Cu, MoS 2 ] holds significant importance in both science and engineering. Ternary nanofluids are vital in advancing thermal management systems, heat exchangers, aerospace, and materials processing applications. Purpose This study investigates the ternary hybrid Carreau nanofluid numerically for thermal proficiency in the inclined magnetized environment. In this study, three distinct nanoparticles of [Ag, Cu, MoS 2 ] and base fluid water over the wedge are used. The velocity of nanofluids is judged under the influence of an inclined magnetic field, and the thermal performance is scrutinized by incorporating the thermal radiation effect. Methodology The physical problem generates partial differential equations, which are transformed into ordinary differential equations (ODEs) through similarity variables. These ODEs are linearized into a system of ODEs and then passed under the bvp4c Matlab program to get the solution. This solution is again trained by an artificial neural network, and further results are obtained with both schemes and compared. Findings The most rapid heat transport analysis is found for ternary hybrid nanofluids compared to bi-hybrid nanofluids. The thermal radiation parameters and the magnetic environment augment the rate of heat transport.

A practical time-dependent model has been constructed to forecast the effectiveness and productivity of a magnetic regenerative refrigerator, as well as to assess its cycle efficiency. The model incorporates many irreversible factors, including the cycle frequency, heat transfer efficiency, and heat leak. Furthermore, it is utilized to scrutinize a magnetic refrigerator that employs spherical Gd particles as the magnetic substance and water as the heat transfer medium. The different cycle steps of the magnetic refrigerator are examined, while the cooling capacity and temperature differential between the two heat exchangers are appraised. The results also show that the magnetic refrigerator can obtain a temperature span of 5 K under 0.8 T magnetic field after 30 cycles in a particular situation. The findings provide valuable information for the future planning and advancement of magnetic refrigeration technology at room temperature.

Heat transfer (HT) technology is rapidly increasing due to the petition for well-organized heating systems and cooling systems in the requisite posited by chemical, automotive, and aerospace industries. Thus, the present investigation examines mixed convective or buoyancy flow induced by the Williamson fluid closer to the stagnation point worsened by hybrid nanoparticles (alumina [Al 2 O 3 ] and copper [Cu]) through a flat upright plate by the influence of the Hall effect. The water-based Al 2 O 3 and copper Cu nanoparticles acknowledging convectively-heated as suitable in the industry or engineering are inspected. The dominant equations are non-dimensionalized using the appropriate similarity parameters, and subsequently, using the bvp4c, these are solved numerically. We thoroughly investigate the effects of numerous pertinent parameters on the transverse velocity, the axial velocity, drag force, temperature, and HT. Two dissimilar outputs are perceived in the circumstance of opposing flow, compared to simply one in the assisting flow. The solutions also showed that the thermal boundary layer length increases and the velocity thickness of the boundary layer decreases as a result of the nanofluid. The higher Weissenberg number causes the gradients for the stable result branch to increase, whereas the gradients for the lower result branch drop. The Lorentz force impact can also be utilized to modify the flow and physical characteristics of HT. In addition, the friction factor in the transverse axis enlarges with the magnetic number for both branches.

This article mainly scrutinizes the heat transfer and flow characteristics of a mixed convection ternary hybrid nanofluid in a porous microchannel considering the catalytic chemical reaction and nonuniform heat absorption/generation. Using appropriate similarity transformations, the modeled equations are converted into reduced ones and then solved via the Runge–Kutta–Fehlberg 4th/5th order method. To strengthen this analysis, the convection mechanism has been deployed. The effect of pertinent physical parameters on the fluid motion and thermal field is displayed, including some important engineering variables like the Nusselt number, Sherwood number, and drag force. The novel outcomes display that the flow reduces with porous permeability and nanoparticle volume fraction. The temperature of the nanofluid improves with nonuniform heat absorption/generation. The concentration decreases in the presence of both homogeneous and heterogeneous reaction intensities. The heat transfer rate enhances for the Eckert number, and a similar influence on the mass transfer rate is noticed for homogeneous reaction parameters. Further, the drag force declines for the Grashof number. The outcomes show that, in all cases, the ternary hybrid nanofluid shows a greater impact than the nanofluid. The attained findings represent applications in the era of cooling and heating systems, thermal engineering, and energy production.

The thermal conductivity of nanofluids (NFs) has emerged as a critical area of research due to its potential to enhance heat transfer in various industrial applications. Non-Newtonian NFs, in particular, exhibit unique flow characteristics under the influence of magnetic fields, making them suitable for systems requiring precise control of fluid dynamics, such as cooling systems in electronics and energy sectors. Owing to its usage, this article presents the magneto-Marangoni convective flow for fluid (phase-I), particle (phase-II), and propagation in tangent hyperbolic NF (copper–ethanol) containing maximum cell swimming speed. This study aims to evaluate the thermal conductivity of magnetized non-Newtonian NFs mixed with dusty particles in the presence of thermal radiation, exploring how magnetic fields and particle interactions affect overall thermal performance. The Gegenbauer wavelet collocation-based scheme was utilized to solve the model and investigate physical attributes such as plate friction, Nusselt number, Sherwood number, and mass flux. The results indicate that the species reaction field is increased by activation energy, whereas it is reduced by chemical reaction. Also, increasing values of thermal radiation tend to improve the heat distribution.