Band 42, Heft 1

Based on the first-principles method of density functional theory, the microscopic mechanism of the effect of addition of alloying element Ru content on the stability and elastic properties of Laves phase TaCr 2 was investigated by parameters such as formation enthalpy, electronic structure, and elastic constants. The addition of Ru atoms tends to preferentially occupy the lattice sites of Cr. With the increase in the Ru content, the alloying ability of Ta 8 Cr 16− n Ru n ( n = 0–6) becomes progressively weaker, the stability gradually decreases, whereas the Poisson’s ratio grows. The bonding peak appears to drop and widen, weakening the bonding strength of Ta–Cr atoms, rendering the shear deformation to be performed easily, thereby improving toughness. When the Ru content rises to 20.83 at%, the bulk modulus, shear modulus, Young’s modulus, and Poisson’s ratio of the alloy attain the maximum value, the brittleness diminishes to the most extent, the resistance to elastic deformation is the strongest, as well at the optimum fracture toughness.

In order to improve the high temperature melting characteristics of bituminous coal with low ash melting point, three kinds of anthracites were used to improve the ash melting characteristics of blended coal to meet the requirement of blast furnace injection. The complete melting temperature of pulverized coal ash had been calculated by using FactSage thermodynamic calculation software. The results showed that after adding different proportions of anthracite with high ash melting point, the deformation temperature, softening temperature, hemispherical temperature, and flow temperature of the blended coal increased. After adding different proportions of Yang Quan anthracite, compared to Bu Lian Ta bituminous coal, the ash melting point of blended coal increased by 98, 136, 149, and 170 K, respectively. The relationship between the ash melting point of pulverized coal and the calculated value of ash complete melting temperature was obtained as: T ST = 0.7098 T C + 257.98.

We present the thermodynamic properties of ZrC (1− x ) N x ceramics at elevated temperature (0–1,000 K) and pressure (0–150 GPa) conditions, explored by density functional theory. We implemented the Debye–Grüneisen quasi-harmonic model in our calculations. In our investigation, we cover elastic constants, elastic moduli, compressibility, ductility/brittleness, hardness, sound velocities, minimum thermal conductivity, melting temperature, anisotropy indices, isothermal bulk modulus, heat capacities, entropy, Debye temperature, Grüneisen parameter, thermal expansion coefficient, and thermal pressure. We address the effect of the structural anisotropy and bonding nature of ZrC (1− x ) N x compounds on their thermal response to extreme conditions. Considering ZrC (1− x ) N x with the x in the range of 0.0, 0.25, 0.5, 0.75, and 1.0, ZrC 0.50 N 0.50 stands out in the response to the applied conditions. At higher temperatures, the thermal expansion of the ZrC 0.50 N 0.50 shows a smaller increase, which makes it a favorable candidate for coating material in cutting tools against commonly used ZrN and ZrC ceramics. Similar behavior is observed for the heat capacity by increasing pressure at higher temperatures, where a smaller reduction is observed. It could be interpreted as a more stable response regarding the application-specific design conditions.

Aiming at the quality problems such as segregation, porosity and shrinkage cavities that are difficult to eliminate due to the size effect of large die-cast steel ingots as large forging blanks, the idea of layered casting of large steel ingots is proposed. The transient heat transfer process and cladding path of the ingot core and cladding layer under different molten steel casting temperatures, different ingot core diameters and different ingot core preheating temperatures were studied by combining numerical simulation and thermal experiments. The research results show that the cladding path has a certain functional relationship with the diameter of the ingot core and the preheating temperature of the ingot core. Obviously, the interfacial melting rate can be significantly improved. The thermal scaling experiment was carried out on the cladding path under the condition of a casting temperature of 1,560°C and no preheating of the ingot core. The microhardness of the interface is higher than that of the clad steel ingot, and the metallurgical bond of the interface is good.

Production data from a vanadium (V)-containing titaniferous magnetite (VTM) smelting blast furnace (BF) ironmaking plant and a V-recovering basic oxygen furnace (BOF) shop were collected over a period of 1 year. The corresponding thermodynamics was analyzed in terms of V reduction in the BF operation and V oxidation in the BOF operation. The thermodynamic calculations were performed using the software Multi-Phase Equilibrium (MPE), in which generalized central atom model was introduced into the description of molten slag and applied for the slag database. The effects of operating conditions on V distribution ratios between slag and hot metal/semi-steel were analyzed and compared with the plant data. The simulated results could reproduce the variation of V distribution ratios with slag temperature and composition and provide the guidance for operators to control V distribution behavior for the better process operation.

The emission of blast furnace (BF) exhaust gas has been criticized by society. It is momentous to quickly predict the comprehensive coke ratio (CCR) of BF, because CCR is one of the important indicators for evaluating gas emissions, energy consumption, and production stability, and also affects composite economic benefits. In this article, 13 data-driven prediction techniques, including six conventional and seven ensemble methods, are applied to predict CCR. The result of ten-fold cross-validation indicates that multiple linear regression (MLR) and support vector regression (SVR) based on radial basis function are superior to the other methods. The mean absolute error, the root mean square error, and the coefficient of determination ( R 2 ) of the MLR model are 1.079 kg·t −1 , 1.668, and 0.973, respectively. The three indicators of the SVR model are 1.158 kg·t −1 , 1.878, and 0.975, respectively. Furthermore, AdaBoost based on linear regression has also strong prediction ability and generalization performance. The three methods have important significances both in theory and in practice for predicting CCR. Moreover, the models constructed here can provide valuable hints into realizing data-driven control of the BF process.

High-strength rebar plays a supporting role in large engineering structures due to its excellent performance. In this study, the effect of different isothermal time treatments (30, 60, 100, and 200 s) at 650°C on the microstructure transformation and mechanical properties of rebars was investigated. The hot-rolling process was simulated by Gleeble-3800 thermal simulator. The microstructure, precipitates, and mechanical properties of high-strength rebar were characterized by scanning electron microscopy, transmission electron microscopy (TEM), and a universal tensile test machine. Results show that when the isothermal time increased from 30 to 200 s, the ferrite grain size decreased from 10.632 to 8.326 μm, and the pearlite lamellar spacing was refined from 0.230 to 0.142 μm. The TEM confirmed that when the isothermal time increased from 30 to 200 s, the nanoscale (Nb, V, and Ti) C precipitates were uniformly distributed in the ferrite matrix and grain boundary, and the size of precipitates decreased from 34.014 to 29.916 nm; thus, the tensile strength increased from 752.477 to 780.713 MPa, and the yield strength increased from 574.714 to 621.434 MPa.

The number density, size and composition of inclusions in U75V heavy rail steel during ladle furnace (LF)–RH refining process were studied by an Aztec-Feature inclusion automatic software which equipped with a field emission microscope. The results showed that the MnO–SiO 2 –Al 2 O 3 -type inclusions were the main inclusions at LF start. The MnO–SiO 2 –Al 2 O 3 -type inclusions were transformed into the CaO–SiO 2 –Al 2 O 3 -type inclusions during the LF refining process because of the Ca and Al elements which were brought by ferroalloy. At the RH start stage, the main inclusions were CaO–SiO 2 –Al 2 O 3 -type inclusions with low melting temperature and CaO–MgO–Al 2 O 3 -type inclusions with high melting temperature in the sample. And, the CaO–MgO–Al 2 O 3 -type inclusions were obviously removed during RH vacuum treatment. The average compositions of CaO–SiO 2 –Al 2 O 3 -type inclusions had no obvious change from RH vacuum holding for 15 min, RH vacuum break to RH soft blowing.

This work efficiently investigated the simultaneous extraction of uranium (U) and niobium (Nb) from a low-grade natural betafite ore by using novel technique, namely, sulfatizing roasting coupled to sulfuric acid leaching process. First, the sulfatizing roasting was adopted to alert the properties of the raw ore, aiming to destroy the crystal structure of the ores and convert the valuable elements to soluble sulfate compounds. Moreover, the influences of the parameters affecting the sulfatizing roasting including roasting temperature, amount of sulfuric acid, and roasting time were studied. The results indicated that the extraction of U and Nb from the ores with sulfatizing roasting was an order of magnitude higher than the extraction of U and Nb from the ores without roasting under the same test conditions. Then, the effects of amount of sulfuric acid concentration, liquid–solid ratio, leaching temperature, and leaching time on U and Nb recoveries were systematically investigated. To verify the process parameters of extracting U and Nb for the novel technique, three validating tests were conducted, and the results showed that over 95% of U and 85% of Nb were leached out under the optimal conditions. The novel technique was proven as advantageous since it conspicuously improved the leaching rates of U and Nb and promoted the refractory natural betafite ores to become an economic source for uranium.

The trivalent chromium (Cr) leached from stainless steel slag can be oxidized into hexavalent Cr with strong toxicity in the natural storage process, thus causing severe pollution to the surrounding soil, water, and atmosphere. Currently, the toxicity hazards caused by high Cr concentrations in plants, animals, and humans have attracted widespread attention from across the world. In this study, an overview is presented regarding the occurrence mode, leaching mechanism, and influencing factors for the presence of Cr in the soil of stainless steel slag under natural landfilling conditions. Meanwhile, a summary is made for the research progress in Cr absorption, transport, and accumulation in the soil–plant system. Besides, allowing for the toxicity and detrimental effect of Cr( vi ) in the soil as well as the application of biological and chemical methods for the remediation of Cr( vi )-contaminated soil, a review is conducted on the approach to recycling Cr from stainless steel slag and the application of chemical remediation and biological methods to remedy Cr-containing soil. Finally, a discussion is conducted about the transfer and transformation behavior of Cr in soil–plant system, the practical application of soil remediation technology and the prospect of research in this field.

AA2195-T8 Al–Li alloy plates were welded by friction stir welding (FSW) at tool rotational speed of 1,000 rpm and tool traverse speeds (TS) of 100–400 mm·min −1 under three types of butting surface conditions, i.e., (1) without butting surface treatment, (2) butting surface milled, and (3) bead-on-plate welding. The effect of welding heat input and butting surface condition on joint line remnant (JLR) and mechanical properties of friction stir welded 2195-T8 Al–Li alloy was investigated comprehensively. In the stir zone of 2195-T8 FSW joints, there exists JLR composed of alumina-particle arrays and microcracks generated from the initial butting surface, and the morphology of JLR would evolve from smooth to serrate as TS increases. Moreover, as TS increases (i.e., the welding heat input decreases), JLR deteriorates the tensile strength of the 2195-T8 FSW joints, with joints prematurely fracturing along JLR. The fracture mode of 2195-T8 FSW joints was considered to be determined by the lower one between strength of JLR ( S JLR ) and strength of the lowest hardness zone ( S LHZ ), and JLR tends to be the fracture path at lower welding heat input. Furthermore, butting surface treatment (milling off oxide layer prior to welding) was found to be able to make the JLR in the 2195-T8 FSW joints less distinct and thus improve S JLR , while fracture along JLR could not be avoided.

In this article, the welding technology of large diameter thick wall 08Cr9W3Co3VNbCuBN (G115) heat-resistant steel pipes for the main steam pipe of a 650°C ultra-supercritical power station boiler has been investigated, and the mechanical properties and microstructure of welded joints at different wall thickness positions have also been analyzed. The results show that the mechanical properties of narrow gap welded joint of 115 mm thick large diameter 08Cr9W3Co3VNbCuBN heat-resistant steel pipe obtained by Gas tungsten arc welding (GTAW) + shielded metal arc welding (SMAW) + automatic submerged arc welding (SAW) can meet the requirements of relevant standards after tempering at 780°C. The tensile failure of the welded joint occurs in the base metal zone far away from the weld, an obvious necking phenomenon appears at the fracture position, and the welded joint has good tensile properties. No δ ferrite phase was found in the weld and heat-affected zone (HAZ). The microstructures of each zone are tempered martensite.

In this article, the effect of shielding gas combinations on gas tungsten arc-welded dissimilar AISI 310 steel and AISI 2205 steel joints was investigated. Two gases such as nitrogen and carbon dioxide were substituted in argon shielding gas and its corresponding improvement in the mechanical, microstructural, machining, and wear aspects of the dissimilar AISI 310–AISI 2205 joints was studied. Weld bead studies, tensile, and weld region microhardness were conducted. X-ray diffraction studies revealed joint intermetallics, and microstructural evaluation was conducted. Machining studies were conducted using drilling experiments. Using local analysis and global analysis, the cutting force variations in the feed direction and cutting direction were studied. Wear tests revealed that the variations in traction force, specific wear rate, coefficient of friction and tribo wear mass loss were studied. A considerable improvement in wear characteristics of AISI 310–AISI 2205 joints was observed by substituting CO 2 and N in shielding gas.

The 6156 aluminum alloy is welded by electron beam welding, and different post-weld heat treatments (PWHTs) are carried out on the joints. The microstructure, mechanical property, and corrosion behavior of the welded joint before and after PWHT are investigated, respectively. Results show that the fusion zone is composed of columnar crystal and equiaxed grain in as-welded (AW) condition. There are mainly α-Al matrix phase, and some strengthening phases β″(Mg 2 Si) and Q(Al 4 CuMg 5 Si 4 ) in weld metal. After PWHT, the quantity of strengthening phases in weldment is greatly increased, and their distribution is also improved. The tensile strength of welded joint is 65.8% of that of the base metal (BM) in AW condition. After the heat treatment of HT2, the strength coefficient of joint reaches 85.1%. There are many dimples on the tensile fracture surface, and the joint obviously presents the characteristic of ductile fracture. The electrochemical corrosion performance and resistance to intergranular corrosion of weldment in AW condition are higher than that of the BM. However, they are decreased to a certain extent after PWHT. Compared with that of the AW joint, the resistance to intergranular corrosion is slightly decreased after PWHT, and that of the HT2 joint is the best among them.

High-calcium bituminous coal has the advantages on combustibility, but its ash melting point is low, and it is easy to slag in blast furnace injection process. In order to explore the ash melting slag formation mechanism of high-calcium bituminous coal, the mineral evolution of ash in the combustion process of high-calcium bituminous coal and the influence of ash components on the liquid formation in the melting process were studied. The results showed that the melting behavior of ash gradually occurs with the change in the morphology, and the main mineral transformation is carried out around different deposition forms of Ca and Si. The liquid phase formation of ash at high temperature is the essential reason of its melting behavior. The higher the content of CaO, the higher the starting temperature of the liquid phase formation. The higher the content of SiO 2 , the lower the starting temperature of the liquid phase formation, and the more the liquid phases generated at a given temperature. Increasing the content of Al 2 O 3 can expand the temperature range of reducing the formation of ash liquid phase to 1,473–1,673 K. When the temperature is above 1,573 K, Fe 2 O 3 can promote ash liquid phase formation.

Blast furnace slag and steelmaking slag, as the main accessory products of iron and steel smelting, are piled up in large quantities due to their huge output, high treatment difficulty and low comprehensive utilization rate, which has a serious impact on the land and environment. In order to improve the comprehensive utilization of steelmaking slag, low basicity blast furnace slag was added to the existing steel slag for quenching and tempering. The influence of basicity on the chemical composition and phase precipitation of mixed slag was analyzed. In the research process, the phase composition and morphology of blast furnace slag and steel slag of Baotou Steel were analyzed using FactSage7.1 thermodynamic calculation software, ZEISS high-resolution scanning electron microscope (SEM), modern fast high-resolution Bruker energy dispersive spectrometer and AMICS-Mining automatic mineral analysis software. The results show that the mineral phase composition of blast furnace slag is mainly calcium aluminum yellow feldspar and that of steelmaking slag is mainly dicalcium silicate(C 2 S), magnesium-iron phase solid solution, rose pyroxene and calcium iron aluminate. When the basicity of the mixed slag is 2.0, it can effectively inhibit the formation of non-cementitious mineral anorthite and promote the formation of better cementitious mineral C 2 S. At the same time, it is found that the melting temperature of mixed slag decreases with the increase in Al 2 O 3 content.

Shrinkage porosity is a typical internal defect in the continuous casting billet, which occurs frequently and is difficult to solve. To explore the influence factors of central shrinkage porosity, a novel unsteady thermomechanical coupling analysis algorithm is developed based on the billet solidification characteristics, and the central shrinkage behavior during the ending solidification process is simulated. Results show that when the casting speed increases from 1.6 to 2.8 m·min −1 and the center outward displacement is reduced from 9.20 × 10 −2  mm to 5.8 × 10 −2  mm, it means casting speed has a significant effect on the formation of shrinkage porosity, and for this caster, the higher casting speed is more suitable for the secondary cooling zone. Without the changes in the solidification structure, when the superheat degree of molten steel increases from 10 to 40°C, the center outward displacement value decreases from 7.12 × 10 −2  mm to 6.91 × 10 −2  mm. In that case, the superheat degree has no obvious effect on the center displacement value.

In this article, physical and numerical simulation of the flow field in flexible thin slab caster funnel mold at high casting speed is carried out with a five-hole submerged entry nozzle (FHSEN), and characteristics of the flow field on funnel mold liquid level under different casting speeds (4, 5, and 6 m·min −1 ) and different submerged depths (130, 160, and 190 mm) are studied by comparing with the new submerged entry nozzle (NSEN) designed. Physical simulation is based on the funnel mold prototype. Numerical simulation is carried out based on FLUENT software, and industrial experiments of two kinds of submerged entry nozzle are also carried out. The results show that in the case of both physical and numerical simulation, the maximum surface velocity of the FHSEN funnel mold is 0.58 m·s −1 , and the funnel mold liquid level is prone to slag entrapment. The NSEN funnel mold’ maximum surface velocity is 0.37 m·s −1 . Compared with the FHSEN, the NSEN funnel mold’ maximum surface velocity decreases by 0.21 m·s −1 , and funnel mold surface velocity decreases significantly. Finally, the accuracy of simulation results is verified by industrial tests, and it is also show that NSEN can greatly reduce funnel mold surface velocity and probability of slag entrapment.

In order to study the effect of cold-rolling deformation and rare earth Y on the microstructure and texture of 3.0% Si-oriented silicon steel, the microstructure and texture of cold-rolled oriented silicon steel with 60, 72, and 86% deformation are analyzed using electron backscatter diffraction and image analysis software. The experimental results show that the deformation band becomes narrower and the distribution of shear bands becomes denser with increasing cold-rolling deformation. Compared to the Y-free steel, cold-rolled sheet containing rare earth Y has greater shear bands. The pinning effect of rare earth Y hinders the dislocation movement, which leads to the increase of kernel average misorientation value and shear bands. With the increase of cold-rolling deformation, the texture concentrates on α and λ. This is mainly due to the change from {100} 〈001〉 to {001} 〈110〉, intensifying λ texture, and the change from {111} 〈112〉 to {111} 〈110〉, thus strengthening the α texture. The texture strength of cold-rolled sheets can be decreased by rare earth Y. But the γ texture strength in cold-rolled sheets containing Y is significantly higher than in those without Y. The γ texture strength can reach up to 7.3, and the strong points are mainly {111} 〈112〉. This is because the number of inclusions in steel increases with the addition of rare earth Y. In the process of grain nucleation, the {111} oriented grains nucleate heterogeneously on the inclusions. It forms a large number of {111} oriented grains and improves the γ texture strength.

In this study, hybrid alloys were obtained by casting method with alloy elements and additive such as Si and MoS 2 , which can be used instead of lead, and compared with Ecobrass and free cutting brass samples used in the market in terms of microstructure, mechanical, and machinability properties. The microstructures of lead-free hybridized brass consists of alpha, beta, and intermetallic compound which were confirmed by the results of X-Ray Diffraction analysis and Scanning Electron Microscopy-Energy Dispersive Spectroscopy. The hardness values of the beta phase in the microstructure are between 180 and 220 Vickers hardness. It has been observed that increasing the amount of beta prime phase also increases the hardness. The machinability of samples was evaluated in terms of surface roughness and chip formation. Chips obtained from samples after machining process were categorized according to ISO 6385-G1 standard. Chip morphologies were examined under optic microscope and scanning electron microscope. The surface roughness value of samples with MoS 2 additives was found to be the lowest due to its lubricity effect. Moreover, morphologies, distribution of phases, and intermetallic compounds in the microstructure are found to have a great impact on the machinability and ultimate tensile strength.

The difficulty of endpoint determination in basic oxygen furnace (BOF) steelmaking lies in achieving accurate real-time measurements of carbon content and temperature. For the characteristics of serious nonlinearity between process data, deep learning can perform excellent nonlinear feature representation for complex structural data. However, there is a process drift phenomenon in BOF steelmaking, and the existing deep learning-based soft sensor models cannot adapt to changes in the characteristics of samples, which may lead to their performance degradation. To deal with this problem, considering the characteristics of multimode distribution of process data, an adaptive updating deep learning model based on von-Mises Fisher (vMF) mixture model and weighted stacked autoencoder is proposed. First, the stacked autoencoder (SAE) and vMF mixture model are constructed for complex structural data, which can initially establish nonlinear mapping relationships and division of different distributions. Second, for each query sample, the basic SAE network will perform online adaptive fine-tuning according to its data with the same distribution to achieve dynamic updating. Moreover, each sample is assigned a weight according to its similarity with the query sample. Through the designed weighted loss function, the updated deep network will better match the working conditions of the query sample. Experimental studies with numerical examples and actual BOF steelmaking process data are provided to demonstrate the effectiveness of the proposed method.

Zn–Al–Mg coating galvanized steel in resistance spot welded (RSW) in different configurations of DC51D was investigated to illustrate the nugget evolution process and mechanical properties of the joints. Results show that the microstructure of welded joints can be divided into nugget zone (FZ), heat-affected zone (HAZ), and base metal zone (BM). FZ was composed of lath martensite. The average hardness value of the weld joint was 110 HV 0.2 while the FZ was up to 300 HV 0.2 due to the formation of lath martensite. The failure modes can be divided into interface fracture (IF) and pull-out fracture occurred (PF) under different welding parameters, in which shear dimples showed had a typical plastic fracture morphology. The best range for welding parameters was found to be 12–18 cycles in which the nugget diameter reached 5.5 mm. The process of nugget evolution in HAZ and FZ was discussed.

As the core foundation of major national equipment, large forgings have a great influence on the national economic construction, the development of national defence equipment and the development of modern cutting-edge science and technology. In the production of large forgings, welding the internal void of forgings is a technical problem that directly affects the quality of large forgings. In view of the phenomenon of void welding in large forgings, the behaviour and mechanism of void welding were deeply studied based on the stretching test and molecular dynamics simulation, combined with a lot of theoretical analysis. The results show that multi-pass stretching deformation is a kind of plastic deformation process which can eliminate void defects. When the forging ratio reaches 2.2, the void can be welded completely and the tensile strength can be restored to the level of the matrix. With the increase of compression deformation, the stress will increase sharply, especially at the grain boundary. In addition, the main void welding mechanism of 30Cr 2 Ni 4 MoV steel is the recrystallization and grain growth mechanism. Recrystallization and grain growth are of great significance for promoting the reduction of void volume and realizing metallurgical bonding of the interface.

To investigate the feasibility of preparing CaO–SiO 2 –Al 2 O 3 inorganic fibers with melting-separated red mud, the properties of the melting-separated red mud were analyzed by X-ray fluorescence, X-ray diffraction, and differential thermal-thermogravimetric analyses. The composition of the melting-separated red mud satisfied the requirements for the composition of inorganic fibers. During the melting of the melting-separated red mud, tetrahedral skeleton fracture reactions occurred at 1,234°C, anionic group reverse binding occurred at 1,250°C, and there was no other obvious reaction peak during the whole melting process, which lasted for 51 min. The minimum suitable fiber forming temperature of the melting-separated red mud melt was 1,433°C, which was 83°C greater than its crystallization temperature, 1,350°C. Within this temperature range, the activation energy of particle movement in the melt was 1008.65 kJ·mol −1 , and the melt exhibited good fluidity. Considering the temperature distribution corresponding to the melting properties of the melting-separated red mud, CaO–SiO 2 –Al 2 O 3 inorganic fibers could be prepared when the melting-separated red mud was subjected to component reconstruction by increasing the silicon content, reducing the aluminum content, and adding a moderate amount of calcium. Quartz sand and light burnt dolomite were used as modifying agents and inorganic fibers were prepared under laboratory conditions. The fibers prepared from the modified melting-separated red mud by adding different amounts of melting-separated red mud had smooth surfaces and were arranged in a crossed manner at the macroscopic level. Their color was grayish-white, and small quantities of slag balls were doped inside the fibers. With an increase in the amount of melting-separated red mud from 50 to 100%, the average fiber diameter increased from 5.5 to 8.0 μm, and their slag ball content increased from 2.9 to 6.0%. Overall, under laboratory conditions, when the amount of melting-separated red mud added was 50%, dolomite was 22.5% and quartz sand was 27.5%, the performance of the fiber was the best.

The process of preparing surface composite by molten salt co-deposition is the result of the mass transfer of active particles in molten salt, electrochemical reduction, and solid diffusion. In this study, we prepared Cr–Ni alloy/low-carbon steel surface composites in NaCl, KCl, NaF, Cr 2 O 3 , and NiO melt salt system successfully, and analyzed the entire diffusion dynamics process, aiming to find out the limiting links and provide ideas for further improving the preparation efficiency. The results show that chromium and nickel ions are simultaneously reduced on the cathode surface through two and one steps, respectively. And an alloy layer with Fe content of 64.52 wt%, Ni content of 28.96 wt%, and Cr content of 6.52 wt% is formed on the surface of low-carbon steel substrate. The average diffusion coefficients of chromium and nickel atoms in the surface composites are 1.16 × 10 −14 and 1.44 × 10 −14  m 2 ·s −1 . The mass transfer process in molten salt is the limiting link in the whole preparation process.

In this article, an attempt was made to improve the efficiency of coated solar panels by using artificial neural networks (ANNs) and response surface methodology (RSM). Using the spray coating technique, the glass surface of the photovoltaic solar panel was coated with silicon dioxide nanoparticles incorporated with polytetrafluoroethylene-modified silica sols. Multilayer perceptron with feed-forward back-propagation algorithm was used to develop ANN models for improving the efficiency of the coated solar panels. Out of the 200 sets of data collected, 75% were used for training and 25% were used for testing. On evaluating the models using performance indicators, a four-input technological parameter model (silicon dioxide nanoparticle quantity, coating thickness, surface temperature and solar insolation) with eight neurons in a single hidden layer combination was observed to be the best. The prediction accuracy indicator values of the ANN model were 0.9612 for the coefficient of determination, 0.1971 for the mean absolute percentage error, 0.2317 for the relative root mean square error and 0.00741 for the mean bias error. Using a central composite design model, empirical relationships were developed between input and output responses. The significance of the developed model was ascertained by using analysis of variance, up to a 95% confidence level. For optimization, the RSM was used, and a high efficiency of 17.1% was predicted for the coated solar panel with optimized factors; it was validated to a very high level of predictability. Using interaction and perturbation plots, a ranking of the parameters was done.

High-temperature coal ash/flue gas corrosion behaviours of three nickel–iron based superalloys for boiler tubes with different Mo and W contents (1.8% Mo + 1.2% W for S 1 alloy, 0.8% Mo + 0.2% W for S 2 alloy, and 0.5% Mo + 2.2% W for S 3 alloy) at 650 and 700°C were studied. The microstructure, phase compositions, and morphologies together with element distribution for corrosion products were investigated with a metallographic microscope, a scanning electron microscope equipped with an energy-dispersive spectroscope, and X-ray diffractometer. The results show that the corrosion resistance of the Ni–Fe-based alloy decreases with the increasing total content of Mo and W in the alloy at both 650 and 700°C; the outer layer of the corrosion products was mainly composed of FeCr 2 O 4 while the inner layer was mainly composed of Cr 2 O 3 . Peeling of the oxide films formed on the surfaces of S 1 and S 3 alloys was observed but no obvious spalling was observed for the S 2 alloy. The reactions among Mo, W, and S in the coal ash/flue gas increased the internal stress in the oxide scale, which would cause the failure of the oxide scale. Graphical Abstract High-temperature corrosion behaviours of three nickel–iron-based superalloys for boiler tubes with different Mo and W contents in simulated coal ash/flue gas at 650 and 700°C were studied. The corrosion resistance of the Ni–Fe-based alloy decreases with the increasing total contents of Mo and W in the alloy at both 650 and 700°C; peeling of the oxide films formed on the surfaces of S 1 and S 3 alloys was observed but no obvious spalling was observed for the S 2 alloy. Reactions between Mo, W, and S in the coal ash/flue gas increased the internal stress in the oxide scale, which would cause the failure of the oxide scale.

Himalayan rock salt contains a variety of minerals and trace elements, which is conducive to human health. The solutions of black rock salt and rose salt are alkaline, and the content of water insoluble matter is 0.34 and 0.083%, respectively. The element composition of water insoluble matter in rock salt is determined and analyzed. It is found that the main component of two kinds of rock salt water insoluble matter is soil. Due to the presence of water insoluble matter in rock salt, according to the different specific gravity of molten sodium chloride and insoluble matter, rock salt was purified by high-temperature melting method. Rose salt is mainly studied during purification. The results showed that the content of insoluble matter in rose salt decreased from 0.083 to 0.0024% after holding at 950°C for 40 min; the contents of arsenic, barium, and lead decreased to 0.0032, 0.61, and 0.21 mg·kg −1 , respectively; the content of sodium increased to 39.24%, the contents of calcium, magnesium, and iron reached to 2,200, 855, and 1.31 mg·kg −1 , respectively.

The focus of this study is to regulate the variation in the input parameters of multiple microwave sources in a high-frequency multimode resonant heating system to achieve uniform heating. First, this study deeply expands the theoretical process of frequency change and proposes a frequency-shifting strategy with hot spot alternation to ensure that the temperature difference range of each hot spot does not continuously expand during the heating process. Then, a sequential quadratic programming algorithm is introduced to reconstruct the input power values to improve the heating efficiency according to the different microwave absorption efficiencies of the heated material at different frequencies. Finally, a numerical calculation model for multi-source microwave power-frequency cooperative heating is established based on the finite-element method, and the temperature uniformity index is effectively calculated. Numerical calculations show that the proposed method can improve the uniformity in single-material heating and multi-material heating cases by 56.8–94.3% and 44.4–76.6%, respectively, over that of fixed-frequency heating while achieving improved heating efficiency on the basis of frequency conversion.

A novel method for CO 2 injection direct smelting vanadium steel (CIDSVS) is proposed. Achieving selective oxidation of phosphorus is essential for the applicability of the suggested process. Under the guidance of thermodynamics, the mechanisms of CO 2 injection dephosphorization and vanadium retention were investigated with CO 2 flow rate and dephosphorization slag composition as experimental variables. The results indicate that CO 2 as an oxygen source can remove 73.8% of phosphorus, while the oxidation rate of vanadium is 17.5%. The dephosphorization process can be divided into two stages: FeO- and CO 2 -dominated experimental processes. In the initial stage of slag feeding, [V] and [P] undergo fast oxidation, and the oxidation amount is positively correlated with the initial FeO content. The high basicity (CaO/SiO 2 ratio) reduces the activity of V 2 O 3 in the slag and promotes the oxidation of [V]. Under the experimental conditions of 1,400°C, the optimal conditions were determined to be a CO 2 flow rate of 1.5 mL·g −1 ·min −1 , a FeO content of 40%, and a basicity B of 2.5. Following the CIDSVS steelmaking operation, 80% of the vanadium is retained, and the impurity elements fulfill the specifications for steel. This method enhances vanadium utilization and is environmentally friendly.

The behavior of void surface healing in 316LN steel samples undergoing thermal plasticity deformation was investigated using the Gleeble 1500 thermomechanical simulator. The characterization of the void surface after plastic deformation was analyzed under different deformation temperatures, deformation amounts, and holding time durations. The morphology evolution and microstructure of the void surface healing zone during thermal plasticity deformation and holding time duration stage were analyzed using electron back scatter diffraction imaging. The mechanism of void surface healing under thermal plasticity deformation was investigated. It was found that the degree of void surface healing increases with the degree of deformation and the duration of the holding time. Dynamic recrystallization occurred continuously at the void surface, resulting in a plethora of crystal defects and a substantial amount of energy. These conditions were conducive to atomic diffusion and migration, thereby promoting the healing process of the void surface. Maintaining high temperature after deformation can continue to provide energy for the diffusion and migration of atoms, promotes the growth of recrystallized grains, and gradually heals the void surface.

The use of aluminum in chassis, bumper, and crash boxes has increased in the last 10 years with an increase in the production of electric vehicles in the automotive industry. The extrusion process has also gained importance because it allows mass production. While basic 6xxx series aluminum alloys such as 6060 and 6063 were used in the early stages of the process, later on, 6005A and 6082 alloys, which provide higher strength, have been used. Alloys with higher strength and crash ability are needed with an increase in safety requirements in automotive. In this study, the effect of chemical composition and heat treatment on the intergranular corrosion strength of 6056 alloys was examined. Another aim of this study is not only to produce high strength and ductility alloy but also to provide good corrosion resistance as automotives are used in different environments for several decades. The 6056 alloys are potential candidate materials for the new-generation electrical vehicles in the automobile industry due to their high strength, weldability, machinability, and impact resistance. Therefore, in our work, we produced 6056 alloy samples in a billet form using the direct chill casting method. Then they were homogenized, and billets were extruded as a box profile. Experimental studies were carried out on 6056 alloys with two different chemical compositions and three different heat treatment conditions (T42, T62, and T76) using Method B of EN ISO 11846 standard for corrosion testing. Crack sizes of metallographic sections from corroded areas were calculated g using a scanning electron microscope. As a result, we found that the addition of Mg to 6056 alloys improves corrosion resistance, while copper reduces it. When Zn is added to the alloys, Mg starts to react with it and forms MgZn 2 , which increases the corrosion progress. Moreover, when heat treatment is applied at T76 conditions, the alloys demonstrate high corrosion resistance.

The accurate control of the endpoint in converter steelmaking is of great significance and value for energy saving, emission reduction, and steel quality improvement. The key to endpoint control lies in accurately predicting the carbon content and temperature. Converter steelmaking is a dynamic process with a large fluctuation of samples, and traditional ensemble learning methods ignore the differences among the query samples and use all the sub-models to predict. The different performances of each sub-model lead to the performance degradation of ensemble learning. To address this issue, we propose a soft sensor method based on multi-cluster dynamic adaptive selection (MC-DAS) ensemble learning for converter steelmaking endpoint carbon content and temperature prediction. First, to ensure the diversity of the ensemble learning base model, we propose a clustering algorithm with different data partition characteristics to construct a pool of diverse base models. Second, a model adaptive selection strategy is proposed, which involves constructing diverse similarity regions for individual query samples and assessing the model’s performance in these regions to identify the most suitable model and weight combination for each respective query sample. Compared with the traditional ensemble learning method, the simulation results of actual converter steelmaking process data show that the prediction accuracy of carbon content within ±0.02% error range reaches 92.8%, and temperature within ±10°C error range reaches 91.6%.

This work used the Kissinger equation to compute the activation energy of phthalonitrile to observe thermal properties. We initiated our investigation by synthesizing phthalonitrile samples, incorporating sulfur-containing curing agents ranging from 2 to 10%. Energy-dispersive X-ray spectroscopy confirmed the success of the curing process. Subsequently, we used thermogravimetric analysis (TGA) to acquire the necessary dataset for input into the Kissinger equation. The TGA results pointed to a direct relationship between the concentration of the curing agent and the thermal stability of the samples. Specifically, a sample treated with a 2% sulfur-containing curing agent demonstrated a moderate thermal stability (Td5%: 527.11°C). However, samples treated with higher concentrations of the curing agent, namely, 5 and 10%, exhibited increased Td5% values of 532.75 and 540.01°C, respectively. The increased thermal degradation-onset temperatures suggest a boost in the cross-linking density and mechanical properties, a result of the increased curing agent concentration. Further substantiating these findings, the Kissinger equation yielded high activation energies of 43.6222, 46.1365, and 67.9515 kcal·mol −1 for the 2, 5, and 10% curing agent dosages, respectively, with R ² values ranging from 0.9650 to 0.9701.

The liquidus temperature and temperature drop coefficients of medium manganese steel were systematically studied using Factsage and differential scanning calorimetry (DSC) experiments. The results indicated that the temperature drop coefficients of C, Mn, Cr, Si, and Al were complex, while the coefficients of Mo, V, and Nb were of a constant value. Based on the temperature drop coefficients, the empirical formula for calculating the liquidus temperature of medium manganese steel was established. The liquidus temperature calculated using the empirical formula was 1422.7°C, while that obtained by the DSC experiment was 1422.9°C. By comparison with different calculation formulas, the liquidus temperature obtained from the formula that was constructed in this study was much closer to the experiment one, indicating the high accuracy of the empirical formula in predicting the liquidus temperature of medium manganese steel.

Long-term dipping corrosion experiments on Incoloy 800H (800H) in molten eutectic MgCl 2 –KCl salt at 1,073 K with and without connection with Ni-201 alloy were carried out. While connecting with Ni-201 alloy, the corrosion rate of 800H was 4.47 ± 0.26 mg·cm −2 ·day −1 (10 −3.55±0.02  A·cm −2 ). However, the corrosion rate for the 800H that was not connected to the Ni-201 alloy was 3.00 ± 0.27 mg·cm −2 ·day −1 (10 −3.71±0.04  A·cm −2 ). Therefore, Ni-201 alloy accelerates the corrosion rate of 800H in the molten MgCl 2 –KCl salt while connecting to each other. In addition, based on the calculation of Gibbs energy of Ni–Fe–Cr alloy and exchange current density of 800H in MgCl 2 –KCl salt, a new Tafel model was developed to predict the corrosion rate of 800H alloys. The corrosion rate calculated by the new model is 10 −3.74  A·cm −2 , which agrees with the experimental data.

The microstructure and mechanical properties of Mg–Al–Zn alloy joints by using autogenous laser beam welding (LBW) and laser-MIG hybrid welding, respectively, are investigated. The results show that the weld formation of the hybrid welding joint is relatively good, and there are mainly α-Mg matrix phases and β-Mg 17 Al 12 strengthening phases in the weld metal. The microstructure in the fusion zone (FZ) of the two joints is different. The LBW joint is composed of columnar crystal and equiaxed dendrite. The hybrid welding joint consists of fine equiaxed grains, and the grain size in the laser zone is larger than that in the arc zone. The microhardness in FZ is higher due to the precipitation of the β-Mg 17 Al 12 phase in this region. Under the optimized welding procedure, the strength coefficient of the two joints is >90%. There are many dimples on the tensile fracture surface of the hybrid welding joint, which is characterized by the pattern of the ductile fracture.

To investigate the feasibility of the refining slag with low fluoride, some oxides such as Al 2 O 3 , SiO 2 , B 2 O 3 , and Li 2 O were used to replace CaF 2 in refining slag with the equivalent weight replacement method, and then the melting temperature and desulphurization capacity of slag were determined. The results show that the melting temperature of slag (CaF 2 < 4 mass% and Al 2 O 3 > 28 mass%) is less than 1,706 K, when CaF 2 is substituted by Al 2 O 3 . This slag is able to decrease [S] in steel to less than 0.0060 mass%. In the case of substitution of CaF 2 by SiO 2 , the melting temperature increases, while the desulphurization rate decreases. The fluxing action of B 2 O 3 is stronger than that of CaF 2 , and the melting temperature decreases to 1,561 K when CaF 2 is substituted by B 2 O 3 . Li 2 O can not only lower the melting temperature of slag but also improve the desulphurization rate.

Nozzle clogging occurs in the interstitial free (IF) steel with high phosphorus (P) more frequently than in IF steel with lower P. To explore the effect of P and Ti on the inclusion behavior in liquid steel, the in situ experiment and theoretical calculations were conducted. High-temperature confocal laser scanning microscopy was used in situ to observe the inclusion behavior at the liquid Fe–P–Ti alloy surfaces, and the attractive and capillary forces were also calculated to quantitatively estimate the effect of P and Ti on the inclusion behavior. The results show that the agglomeration of Al 2 O 3 inclusions involves four steps: dispersed Al 2 O 3 particles in liquid alloy; formation of Al 2 O 3 chain structure; bending of the Al 2 O 3 chain, and sintering and densification of the chain structure. The addition of Ti and P in the steel can increase the agglomeration time of inclusions, indicating the impeding effect of P and Ti on the inclusion aggregation. Furthermore, the orientation factor is proposed to estimate the direction of movement of the small inclusion crossing between large inclusions, and the experimental results confirm its validity.

The mayenite Ca 12 Al 14 O 33 material, owing to its oxide ion conducting behavior and the low cost of raw materials, has the potential of being applied in solid oxide fuel cells as an electrolyte. However, suffering from the relatively low oxide ion conductivity, there is still a long way to go for its practical application. To enhance the oxide ion conduction in Ca 12 Al 14 O 33 , many efforts have been endowed to this from different research groups but hardly succeeded. In this work, the Ca 12 Al 14 O 33 -based materials with Y, In, and Cu-doping on the Ca or Al sites were fabricated through a traditional solid-state reaction method (for Y-doping on Ca and Cu-doping on Al) or a glass-crystallization method (for In-doping on Al), with their electrical conductivities being studied. The results revealed that the solid solution regions of Ca 12− x Y x Al 14 O 33+ δ , Ca 12 Al 14− x In x O 33 , and Ca 12 Al 14− x Cu x O 33− δ were 0 ≤ x ≤ 0.15, 0 ≤ x ≤ 0.1, and 0 ≤ x ≤ 0.3, respectively. The electrical conductivities of all these doped materials were investigated.

The experimental schemes of lanthanum (La) treatment, yttrium (Y) treatment, and La/Y mixed treatment of inclusions in SWRH82B steel were used. The size distribution, number density, inter-surface distance, the degree of homogeneity, and the area density of inclusions in the test steel were determined. The results show that the rare earths have a certain refinement and homogenization effect on the inclusions, and the mixed rare earths have the best effect on the inclusions in the steel. The average size of inclusions after mixed rare-earth treatment is 1.23 μm, the average size of inclusions after rare-earth La treatment is 1.79 μm, and the average size of inclusions after rare-earth Y treatment is 1.37 μm. Thermodynamic calculations show that the affinity of rare earths to oxygen in steel is higher, and the affinity to sulfur is lower. La and oxygen–sulfur have a higher affinity, and the affinity of Y and oxygen–sulfur is lower. In addition to single inclusions, there are complex inclusions in the steel.

Co-based alloys are known to be high oxidation-resistant material and used in several high temperature applications. During high temperature oxidation, duplex oxides containing Co and Cr were formed. It was thermodynamically elucidated that when the growing scale was thick enough, the partial pressure of O 2 in the scale dropped. Then, the reduction of CoO occurred for promoting O 2 which was responsible for Cr 2 O 3 production. This work experimentally proved this point by in situ characterising Co-27Cr-6Mo at high temperatures in air by X-ray diffractometer in a grazing incident mode and metallic Co was confirmed to be formed by the reduction of CoO consistent with the image taken and analysed by field emission scanning electron microscope, energy-dispersive X-ray, and electron backscatter diffraction. Furthermore, the change in lattice parameter and the phase transition were observed when the temperature was altered.

In view of the multi-physical field coupling and time-varying characteristics of the microwave heating medium process, how to dynamically plan the state characteristics of multiple microwave sources and optimize the material temperature uniformity becomes the focus of this article. To this end, first, algebraic graph theory is used to construct the multiple microwave sources as a multi-agent system, and a perfect communication topology is established to ensure the transfer and sharing of information. Second, according to the real-time temperature distribution of the material, an event-triggered adaptive dynamic planning algorithm is used to co-operate with the power input of the multiple microwave sources to ensure that no new hot spots are generated during the optimization of the temperature distribution using the self-organizing properties of the medium. Finally, a numerical calculation model for optimizing a mixture of integer and continuous variables is solved using the finite-element method. The experimental and numerical results show that this article improves the temperature uniformity by 32.4–73.5% and the heating efficiency by 14.3–39.4% compared to the generic heating model, and the feasibility of the method is verified by the different shapes of the heated material.

Round-robin measurement of surface tension of high-temperature liquid platinum was conducted free of any contamination from the supporting materials and oxygen adsorption, using an electrostatic levitator (ESL), two electromagnetic levitator (EML), and an aerodynamic levitator (ADL). The measured temperature dependences of the surface tension using ESL and two EMLs were in good agreement and were expressed as σ = 1,798 ± 74.3 − ( 0.12 ± 0.0445 ) × ( T − 2,041 ) \sigma =\mathrm{1,798}\pm 74.3-(0.12\pm 0.0445)\times (T-\mathrm{2,041}) [10 –3 N·m –1 ] (1,900–2,600 K). However, the surface tension values measured with ADL were slightly lower than those exceeding the uncertainty of the measurement plots at high temperatures.

The objective of this study was to produce composites with a uniform distribution of aluminum nitride (AlN) reinforcing particles in the magnesium (Mg) metal matrix composites. In this study, experiments were carried out to evaluate the effect of time and temperature on the nitridation of aluminum to form AlN and its distribution in Mg composites. High-temperature production of AlN in Mg alloys melts using the ammonia gas bubbling method was investigated. The effect of ammonia bubbling time and temperature at a flow rate of 0.1 liters per minute on the amount of AlN formation was studied. Bubbling of ammonia gas resulted in the in-situ formation of AlN in Mg alloys, yielding AlN-reinforced Mg alloy composites. The AlN formation in the alloy was increased with increasing bubbling time. The rate of AlN formation was found to be 0.34 g·min −1 at 1,073 K. An average yield of AlN (wt%) was 6.47, 29.65, and 27.43 at 973, 1,073, and 1,173 K, respectively. An activation energy of 59.57 kJ was determined for the nitridation process. The magnitude of activation energy indicates that the reaction proceeds in the mixed regime with control of both nucleation and interface diffusion. The product was characterized using X-ray diffraction (XRD), optical microscopy, and scanning electron microscopy. The characterization of samples showed that the AlN particles distributed throughout the alloy matrix. The AlN particles formed in-situ are small in size, and uniform dispersion of AlN particles was observed at higher bubbling times and at higher temperatures. The AlN crystallite size increased with an increase in bubbling time and temperature. The XRD characterization results showed that the composite formed in-situ was composed of (Mg), intermetallic γ-(Mg, Al), and AlN phases. The Rockwell hardness of the in-situ composites was higher than the un-reinforced Mg alloy, and the hardness increased with an increase in the AlN wt% in the Mg alloy composites.

The lightweight alloy sheet materials have been widely used in industries such as automobiles, aviation, and aerospace. However, there are huge challenges in the structural joining process. Likewise, industries are probing new technologies and are rapidly adapting to more complex light alloy materials. The ultrasonic metal welding is a reliable solid-phase joining technology, which has incomparable development prospects in the high-strength joining of lightweight alloy sheet materials. This article summarizes the research progress of ultrasonic welding of aluminum alloy, magnesium alloy, and titanium alloy thin plates in recent years. The key features of this review article are the ultrasonic welding process, advantages, applications, and limitations. It introduces the welding process parameters to explore the breakthroughs for straightforward direction. Furthermore, to strengthen the phenomena, the current state of the ultrasonic welding of lightweight alloys and their future perspectives are also reflected.

In this study, the eutectic temperature and latent heat of Al–Si- and Zn–Al–Mg-based eutectic alloys were determined using differential thermal analysis (DTA) and differential scanning calorimetry measurements in order to identify eutectic alloys for latent heat storage in the eutectic temperature ranges of 450–550 and 300–350°C. First, the eutectic compositions of the Al–Si–Cu–Mg–Zn and Zn–Al–Mg–Sn alloys were identified using scanning electron microscopy with energy-dispersive X-ray spectroscopy and DTA in two steps. In the second step, metallographic analysis was repeated until a uniform eutectic microstructure was obtained. Thermophysical analysis revealed that the eutectic temperatures of several types of Al–Si- and Zn–Al–Mg-based eutectic alloys were within the targeted temperature ranges with relatively high latent heat. These results confirmed that Al–Si- and Zn–Al–Mg-based eutectic alloys have suitable properties as phase change materials for use in the 300–350 and 450–550°C temperature ranges.

Metallic phase change materials (MPCMs) are attracting considerable attention for their application in thermal energy storage. Al–Si alloys are considered potential MPCMs; however, to develop storage systems/modules, it is crucial to fabricate corrosion-resistant materials for MPCMs. In this study, the corrosion behavior of Co−28Cr−6Mo−1.5Si (wt%) alloy was examined via immersion tests in commercial Al−Si alloy (ADC12) melt at 700°C for 10 h. The results were compared to those obtained for pure Al. Substrate thickness loss measurements revealed that the liquid metal corrosion was more severe in the Al−Si melt than that in pure Al, suggesting an increased reactivity due to Si addition. Interfacial analysis elucidated a direct reaction between the alloy substrate and molten Al in both cases. Furthermore, the formation of oxides such as Al 2 O 3 and SiO 2 did not contribute to corrosion resistance.

Carnot batteries, a type of power-to-heat-to-power energy storage, are in high demand as they can provide a stable supply of renewable energy. Latent heat storage (LHS) using alloy-based phase change materials (PCMs), which have high heat storage density and thermal conductivity, is a promising method. However, LHS requires the development of a PCM with a melting point suitable for its application. For the Carnot battery, the reuse of a conventional ultra-supercritical coal-fired power plant with a maximum operating temperature of approximately 650°C is considered. Therefore, developing a 600°C-class alloy-based PCM is crucial for realizing a highly efficient and environmentally friendly Carnot battery. Using thermodynamic calculation software (FactSage), we found that Al-5.9 mass% Si-1.6 mass% Fe undergoes a phase transformation at 576–619°C, a potential 600°C-class PCM. In this study, we investigated the practicality of an Al–Si–Fe PCM as an LHS material based on its heat storage and release properties and form stability. The examined Al–Si–Fe PCM melted until approximately 620°C with a latent heat capacity of 375–394 J·g −1 . Furthermore, the PCM was found to have a thermal conductivity of approximately 160 W·m −1 ·K −1 in the temperature range of 100–500°C, which is significantly better than that of conventional sensible heat storage materials in terms of heat storage capacity and thermal conductivity.

This study is part of a series of studies aimed at measuring the thermophysical properties of molten phase change material-type metallic thermal energy storage materials near 873 K (600°C). The target material is Al–Si based alloys. First, as a feasibility study, density measurements of the molten state of three Al–Si binary alloys (Al–12.2Si, Al–50Si and Al–90Si in atomic%) were performed. A highly accurate non-contact density measurement method based on the static magnetic field superposition electromagnetic levitation (EML) method was employed as the density measurement method. The validity of this experimental method was confirmed, and density of molten Al–Si base alloys (ADC12 and Al–5.9mass%Si–1.6mass%Fe) were measured as a function of temperature with an expanded uncertainty of 1.2%. In addition, the surface tension of the alloys was measured by the droplet oscillation method using the EML technique. The surface tension was successfully obtained as a function of temperature with expanded uncertainty of 2.3%.

Fe–26Si–9B alloy is a promising high temperature phase change material (HTPCM), due to its high heat of fusion, small volumetric change, abundance, and low cost. Additionally, graphite has been identified as a promising candidate for use as a container material for this alloy. In this study, the feasibility of using graphite for Fe–26Si–9B HTPCM is investigated in a pilot-scale. Specifically, 4–5 kg Fe–26Si–9B master alloys were melted in graphite crucibles using an induction furnace, which underwent 2–3 thermal cycles in the temperature range of 1,100–1,375°C. The results showed that SiC and B 4 C precipitates were formed in the alloys. However, these carbides were found to be present only on the surface of the solidified alloys and not in the main body. Still, the chemical composition of the Fe–26Si–9B alloy remained relatively stable during the thermal cycles. It was also seen that the graphite crucible withstood the temperature cycles without cracking. Therefore, the use of graphite as a container for Fe–26Si–9B phase change material is a promising approach.

A powder mixture of UO 2 and TiO 2 was mechanochemically treated in a planetary ball mill under Ar atmosphere for 1 h using a tungsten carbide vial and balls as the milling medium. Such mechanochemical (MC) treatment reduced the crystallinity of UO 2 and TiO 2 . The mechanochemically treated powder mixture was heated at 700–1,300°C for 6 h under Ar atmosphere and analyzed by X-ray diffraction analysis, scanning electron microscopy-energy-dispersive X-ray spectroscopy, and X-ray absorption fine structure analysis. For comparison, a UO 2 and TiO 2 mixture without MC treatment was heated and analyzed under the same conditions. UTi 2 O 6 did not form below 1,100°C without MC treatment and only the starting materials were observed. At 1,200 and 1,300°C, a small amount of UTi 2 O 6 and equal amounts of UTi 2 O 6 and UO 2 were formed, respectively. The mechanochemically treated sample produced nearly pure UTi 2 O 6 containing small amounts of UO 2 impurities when heated above 900°C for 6 h. UTi 2 O 6 was highly crystalline and uniform regardless of the synthesis temperature. It is suggested that the crystallinity of UO 2 and TiO 2 was reduced and the formation of UTi 2 O 6 was promoted by MC treatment.

This report investigates the thermal performance of light-emitting diodes (LEDs) using a heat sink structure based on an optimized design and a sprayed cuprous oxide (Cu 2 O) coating. An orthogonal array of 18 aluminum plates with various heat-dissipated structures was created. The optimal junction temperature of the LED package is determined by using the signal-to-noise ratio (S/N) of the heat-dissipated structure based on Taguchi’s method as well as the heat dissipation coating. According to the analysis of variance, the most important factors that influence the junction temperature can be obtained as the depth of groove, the layout of holes, the layout of LEDs, and the number of Cu block. These significant factors constituted approximately 91.06% of the variation in the experiment. The results show that by optimizing the structure of the LED heat sink based on the heat-dissipated coating, the efficiency of the junction temperature is increased by 23.88%. Also, a gain of 1.30 dB corresponds to a 9.67% reduction in variance, which indicates the improvement through the optimal setting by 1.162 times of variance, showing good reproducibility. Overall, the coating is based on the optimized design of the structure of the heat sink that has good heat transfer capability, which can provide a good solution to the heat-dissipated problem of LED and further give guidance to the future development of LED.

A proton-exchange membrane fuel cell (PEMFC) generates electricity, heat, and water from oxygen and fuel. Hydrogen is recommended as a fuel because it is a renewable fuel when manufactured, for example, by water electrolysis using renewable energy power. Porous metal has excellent characteristics such as controlled permeability, low density, and high porosity. Corrosion is now the most major hurdle to the use of porous metal in PEMFCs, and owing to the porous metal’s complicated internal structure, additional challenges must be addressed in the coating preparation process. As a result, this article figures out how to successfully handle the porous metal corrosion problem in a PEMFC setting, which increases the porous metal utilization in the fuel cell industry. This article also examined the flow field in PEMFC and important characteristics. The influence of flow field in the fuel cell was also investigated.

Electric power resources are the core energy for a country’s economic development and growth. China is at the peak of electric energy consumption at this stage. Improving the accuracy and integrity of electric energy metering technology is of great significance for evaluating the use and consumption of resources in China. Under the background of artificial intelligence, this research analyzes and studies the integrated module, demand status, performance optimization, and coupling degree of the electric energy metering system (hereinafter referred to as EES) through the application of two different types of sensors. The results show that the application of intelligent sensors has a better integration effect with the system management of electric energy metering, which plays a very important role in promoting the sustainable development of automation and informatization of the EES.

In recent years, domestic and international policies to support energy-efficient buildings have been intensively introduced, and a consensus has been reached in the direction of green buildings. Building photovoltaic integration is a key technology to solve the demand for electricity in energy-efficient buildings. Meanwhile, prefabricated assembly house construction, as a common construction technology in the current building field, has the advantages of a short construction period, low project cost, a wide range of applications, and high structural stability. Green building and building industrialization are the direction of future construction industry development, combining building photovoltaic (PV) integration with assembly building, breaking down the whole structure into simple components in the factory standardization, batch production, and then on-site assembly, can reduce the mold cost, speed up the construction speed, and improve economic efficiency. The PV solar integrated assembled facade is in line with the concept of energy saving, low carbon, and environmental protection, with significant social benefits, which helps to promote rapidly in the market. In this article, by analyzing the performance and characteristics of PV modules, we propose the design method of PV-integrated prefabricated components for assembled buildings based on sensing technology, extract relevant design parameters from the database of building PV-integrated components, and test the feasibility of the modeling scheme in four stages of engineering design. The use of the results shows that the method of this article can target to improve the accuracy of PV-integrated prefabricated components, ensure the efficiency of component production and processing, and play an important role in supporting the widespread application of modern construction technology for building PV-integrated prefabricated assemblies.

This study examines the utilization of metal-cored filler wire in conjunction with the gas metal arc welding (GMAW) technique for welding high-strength S690QL steel. Since welding parameters significantly impact the bead quality and weld joint integrity, the main objective was to identify the optimal welding parameters. To achieve this, the input variables including the current ( A ), voltage ( V ), and gas flow rate (GFR), and their effects were evaluated for reinforcement ( R ), width ( W ), depth of penetration (DOP), and the width of the heat-affected zone (HAZ). For a more efficient and cost-effective investigation, a Box–Behnken design, which is based on response surface methodology, was used for bead-on-plate trials. Mathematical regression models, derived from experimental data, were rigorously validated using the analysis of variance, main effects plots, residual analysis, and the R 2 and Adj. R 2 values. Additionally, the heat transfer search (HTS) algorithm was employed for process optimization. While single-objective optimization provided optimal settings for individual responses, simultaneous optimization aimed to strike a balance between multiple, sometimes conflicting, objectives. This comprehensive approach resulted in specific values, including a reinforcement ( R ) of 4.285 mm, a width ( W ) of 9.906 mm, a DOP of 2.039 mm, and an HAZ width of 2.020 mm. These values were achieved with specific input parameters: current (221 A), voltage (24 V), and GFR (21 L·min −1 ). The Pareto solutions offered a nuanced selection of the most suitable configuration, taking into account the desired values for R , W , DOP, and HAZ. The close alignment between predicted and experimentally measured values for the responses highlights the precision and suitability of the HTS algorithm in estimating critical bead geometries during GMAW of S690QL plates.

The micro plasma arc welding process is associated with different physical phenomena simultaneously. This results in complexities to comprehend the actual mechanism involved during the process. Therefore, a robust numerical model that can compute the weld pool shape, temperature distribution, and thermal history needs to be addressed. Unlike, other arc welding processes, the micro plasma arc welding process utilizes thin sheets of thickness between 0.5 and 2 mm. However, joining thin sheets using a high-density arc welding process quickens the welding defects such as burn-through, thermal stresses, and welding-induced distortions. The incorporation of a surface heat source model for computational modeling of the high energy density welding process impedes heat transfer analysis. In that respect, researchers have developed numerous volumetric heat source models to examine the welding process holistically. Although, selecting volumetric heat source models for miniature welding is a significant task. The present work emphasis developing a rigorous yet efficient model to evaluate weld pool shape, temperature distribution, and thermal history of plasma arc welded Ti6Al4V sheets. The computational modeling is performed using a commercially available COMSOL Multiphysics 5.4 package with a finite element approach. Two different prominent thermal models, namely, Parabolic Gaussian and Conical power energy distribution models are used. A comparative analysis is carried out to determine the most suitable heat source model for evaluating temperature distribution, peak temperature, and thermal history. The analysis is done by juxtaposing the simulated half-cross-section weld macrographs with the published experimental results from independent literature. The numerical results showed that the proximity of top bead width magnitude was obtained using the Parabolic Gaussian heat source model for low heat input magnitude of 47.52 and high heat input magnitude of 65.47 J·mm −1 , respectively. In terms of percentage error, the maximum top bead width percentage error for the Parabolic heat source model is 13.26%. However, the maximum top bead width percentage error for the Conical heat source model is 18.36%. Likewise, the maximum bottom bead width percentage error for the Parabolic heat source model and the Conical heat source model is 12.3 and 25.8%, respectively. Overall, it was observed that the Parabolic heat source model produces the least deviating outcomes when compared with the Conical distribution. It was assessed that the Parabolic Gaussian heat source model can be a viable heat source model for numerically evaluating micro-plasma arc welded Ti6Al4V alloy of thin sheets.