Volume 66, Issue 10

Build orientation in additive manufacturing technology is a pre-process application that affects many parameters, such as the volume of the support structure, part quality, build time, and cost. Determining the optimum build orientation for one or more objectives for complex parts is an error-prone puzzle. This study evaluates the behavior of cuckoo search algorithm, differential evolution, firefly algorithm, genetic algorithm, gray wolf optimizer, Harris hawks optimization, jaya algorithm, moth flame optimizer, multi-verse optimizer, particle swarm optimization, A Sine cosine algorithm, salp swarm algorithm, and whale optimization algorithm to determine the optimum build orientation of the component to be manufactured additively. The efficiency of these algorithms is evaluated on the build orientation problem of two complex components considering undercut area and build height as objective functions. Thus, the feasibility of these algorithms for real-world additive manufacturing problems is revealed. According to results obtained from the extensive analysis, the cuckoo search algorithm is the best alternative for minimizing undercut area, considering its robustness. However, the required time to solve the problem is as much as almost twice that of other algorithms. The firefly algorithm and particle swarm optimization algorithm are the best alternatives for minimizing build height.

This research is the first attempt in the literature to combine design for additive manufacturing and hybrid flood algorithms for the optimal design of battery holders of an electric vehicle. This article uses a recent metaheuristic to explore the optimization of a battery holder for an electric vehicle. A polylactic acid (PLA) material is preferred during the design of the holder for additive manufacturing. Specifically, both a hybrid flood algorithm (FLA-SA) and a water wave optimizer (WWO) are utilized to generate an optimal design for the holder. The flood algorithm is hybridized with a simulated annealing algorithm. An artificial neural network is employed to acquire a meta-model, enhancing optimization efficiency. The results underscore the robustness of the hybrid flood algorithm in achieving optimal designs for electric car components, suggesting its potential applicability in various product development processes.

Through numerical simulation, this study explores the effect of vibration-impact composite electric spark (VIES) surface treatment technology on the temperature and thermal stress fields of 2024-T3 aluminum alloy surfaces. The depth of the molten pool and residual stress are evaluated using orthogonal experiments to score different experimental schemes, resulting in three experimental parameters categorized as good, medium, and poor. The study then examines the temperature and thermal stress fields for these three sets of parameters during the strengthening process. The results indicate that, considering the temperature field, the distance between the heat source and the work piece directly affects the heating efficiency and temperature distribution. An appropriate distance and sufficient dwell time are essential for creating the ideal molten pool thickness. Analysis of the stress field results shows that in the early stage of strengthening, the inertia force of the small spheres is dominant, while in the later stage, the stress field created by the electric current becomes decisively dominant. This indicates that the electric current is the core of the three influencing factors in the orthogonal experiment.

Tincal ore is a preferred material in many industrial applications, especially without water. It is important to dehydrate boron ores so that they can be used in materials engineering. For this purpose, some heat treatments must be carried out. Heat treatments are associated with additional costs. It is possible to model heat treatments using artificial intelligence methods, determine optimal process conditions and achieve the desired results with much less processing effort. In this study, a dehydration process was first carried out to dehydrate tincal ore and ANN (artificial neural networks) modeling of this process was investigated using the parameters of temperature, time and amount of ore. The possibility of achieving the desired H 2 O, B 2 O 3 and Na 2 O concentration values in the dewatering process in the shortest time and by the shortest route was investigated using the ANN model. In the modeling, a single model was designed for the changes in concentrations and this model was trained separately for each. The result of the modeling was that the R 2 values for all three models were close to each other and were approximately 0.98. It was thus shown that the ANN method can be successfully modeled for dewatering processes.

The electric current activated/assisted sintering (ECAS) method enables various kinds of materials to be produced much faster and environmentally friendly compared to conventional sample production systems. The main handicap of this system is that the heating regime varies according to the material type even the chemical composition of the same type of material and causes partial melting due to the sudden current flow. Previously, the ECAS output equivalent circuit is modeled as a temperature-dependent resistor in the literature. This study shows that it is insufficient to model the ECAS output consisting of a container and two stiffs as a resistor considering experimental waveforms. We report the discovery of a capacitive effect at the output of the ECAS system that has not been reported before. We have given an equivalent electrical circuit for the ECAS system output and examined the effect’s temperature dependence. The circuit model, which consists of a parallel resistor-capacitor ( R p -C) circuit in series with another resistor ( R s ), is suggested for the container and the stiffs. By using the experimental data, the equivalent circuit parameters are calculated by curve-fitting. The temperature dependence of the equivalent circuit parameters is also examined. Possible explanations for the capacitive effect are given. Such a model and further examining the effect may help design better ECAS systems.

The welded joints are structures with significant heterogeneity, indicated by their fundamental segmentation into base metal (BM), heat affected zone (HAZ), and weld metal (WM). The heat affected zone, having width in millimeter scale for fusion welding processes, is further segmented into several characteristic regions, having differences in grain structure and size. The microstructural heterogeneity results in significant differences in mechanical properties of individual welded joint zones. Mechanical testing of such small material volumes is inconvenient, or even impossible, using the standard size specimens proposed in testing standards. Requirement to precisely position the specimens, even ones with subsize dimensions, and investigate mechanical properties of specific narrow HAZ regions presents certain challenge. This work investigates the X welded joint of S690QL1 grade high strength steel (HSS), welded with slightly overmatching filler metal. The material tensile properties are tested, using small scale specimens and indentation methods. Small scale specimens are ASTM E8 round tensile subsize and flat sheet mini tensile specimens (MTS). The indentation methods include hardness testing and profilometry-based indentation plastometry (PIP) method, to gain additional insights into material stress–strain behavior. Finally, paper evaluates the testing methods, comparatively processes the collected experimental data, and provides guidelines for heterogeneous structures testing.

The thinner flaked Al powders are used to improve the strength of the B 4 C/Al composite. The effect of the flaked Al powder on distribution of B 4 C particles is investigated. The tensile properties of the B 4 C/Al composites with the flaked Al powders are also studied. The results show that during ball milling process, spherical Al powders are flaked with the thinner thicknesses and larger diameters. The thinner flaked Al powders are not easy to be deformed and are bonded together as the laminated structure after thermal compression. B 4 C particles are evenly dispersed and embedded in Al laminated structure. With increasing the volume fraction of B 4 C particles, the deformation of the thinner flaked Al powders become difficult and the thinner flaked Al powders coat on the surface of B 4 C particles, resulting in the disappearance of the laminated structure of the thinner flaked Al powder.

The effect of hydrogen on the ballistic performance of aluminum (Al) 5083H131 was examined both experimentally and numerically in this study. Ballistics tests were conducted at a 30° obliquity in accordance with the ballistic test standard MIL-DTL-46027 K. The strike velocities of projectiles were ranged from 240 m   s −1 to 500 m   s −1 level in the room temperature. Electrochemical hydrogen charging method was utilized to introduce hydrogen into material. Chemical composition of material was analyzed using energy dispersive X-ray (EDX) analysis. Instant camera pictures were captured using high-speed camera to compare H-uncharged and H-charged specimen ballistics tests. The volume loss in partially penetrated specimens were assessed using the 3D laser scanning method. Microstructural examinations were conducted utilizing scanning electron microscopy (SEM). It was observed that with the increased deformation rate, the dominance of the HEDE mechanism over HELP became evident. Furthermore, the experimental findings were corroborated through numerical methods employing finite element analysis (FEM) along with the Johnson–Cook plasticity model and failure criteria. Inverse optimization technique was employed to implement and fine-tune the Johnson–Cook parameters for H-charged conditions. Upon comparing the experimental and numerical outcomes, a high degree of consistency was observed, indicating the effective performance of the model.

Within the scope of this study, composite structures were produced by reinforcing Al7075 with 6 mm size glass fiber (GF) scrap at different weight rates (2–3 %) using the infiltration method. Mechanical and metallurgical examination of unreinforced Al7075 samples and reinforced Al7075 composite samples were carried out. After the aging heat treatment of the samples, pin-on-disc wear and hardness tests were performed. FESEM and EDS analyses were conducted to examine the hardness and microstructural changes caused by the applied processes on the samples. It was observed that GF reinforcement increased the hardness of the material and there was full wettability between Al 7075 and GF. Thus, wear resistance increased. The highest hardness and wear resistance were obtained in the 6 h aged 2 wt.% GF-reinforced Al 7075 matrix hybrid composite sample. In addition, it was observed that the distribution of GF scrap added as reinforcement at a rate of 2 wt.% in Al 7075 was homogeneous, and the hardness measurements taken from different areas were similar.

The study investigates fatigue failure, a common phenomenon in machine elements subjected to cyclic stresses. The analysis emphasizes that the actual stress experienced by materials often falls below their tensile and yield strengths due to repetitive variable stresses, leading to fatigue damage. Fatigue life is measured by the number of cycles endured before failure. This paper focuses on the aluminum alloy of AlSi10MgMn, extensively used in manufacturing due to its strength, low density, and corrosion resistance. Experimental procedures encompassed tensile testing, microstructural examination, SEM analysis, and fatigue testing. Tensile tests provided initial stress values for fatigue testing. Microstructure analyses verified that heat-treated samples exhibited precipitates. SEM analysis disclosed microstructural characteristics, while fracture surface examinations demonstrated higher fatigue resistance in heat-treated specimens. Hardness measurements were conducted, with heat-treated samples showing higher values. Theoretical calculations based on stress and cycle numbers were compared to experimental fatigue results. The derived equations aligned well with the tests. Ultimately, the study underlines the importance of heat treatment on material behavior and fatigue resistance, shedding light on alloy performance and durability enhancement.

Springback, one of the fundamental properties of parts formed by V bending, is the dimensional deviation caused by elastic recovery. Numerical estimation and compensation of springback is essential because it affects the workpiece’s dimensional accuracy and geometry and will cause serious errors, especially during the assembly process. This study investigated the effects of process parameters such as sheet thickness and die angle on springback behavior on 1,050 aluminum experimentally and numerically. Experiments were planned according to Taguchi’s L9 orthogonal array. Sheet thickness (1 mm, 1.5 mm, and 2.5 mm) and die angle (90, 135 and 150°), were selected as forming parameters. Springback was calculated after the tests. Optimization of the parameters was evaluated using the signal/noise ratio approach. The effectiveness of parameters on results was determined by analysis of variance (ANOVA). It has been observed that the springback angle decreases with increasing sheet thickness, but springback angle decreases with increasing die angles. It has been seen that the experimental and numerical study results confirm each other. The variance analysis determined that the die angle was the most dominant springback parameter (90.9 %). Second is the sheet thickness (5.79 %).

In this study, Mg–3Zn–xZr ( x  = 0, 0.5, 1, 2 and 3) alloy were produced using powder metallurgy incorporating high-energy ball milling. Scanning electron microscope (SEM), energy dispersive X-ray (EDX) analyzer and X-ray diffraction (XRD) have been used to investigate the microstructure, chemical composition and phase distribution of the samples. XRD results show that the Mg solid solution wholly formed, and the milled powders were single phase, and no secondary phase was observed. While the secondary phases were formed after sintering. Hardness of Mg–Zn–xZr sample increased from 58.8 Hv (for Zr = 0) to 87.81 Hv with addition of 3 wt.% Zr. The result shows that the corrosion potential of Mg–Zn–Zr alloy was more positive than Mg–3Zn. However, the Mg–3Zn–Zr alloy exhibited higher corrosion current than Mg–3Zn due to galvanic effect of Zr rich area. All of Mg–3Zn–Zr alloys showed better antibacterial and biocompatibility properties than Mg–3Zn alloy due to the presence of Zr as additive. According to the mechanical, corrosion, and biological evaluations in this study, it can be concluded that the Mg–3Zn–1Zr alloy can be used as a suitable biomaterial for the use of orthopedic implants.

Polyvinyl alcohol (PVA) is a biodegradable synthetic polymer with high chemical resistance and excellent mechanical and oxygen barrier properties. Besides these superior properties, it is water-soluble, which provides its wide usage. However, its solubility depends on some factors. Although the temperature is one of these factors and increasing temperature could promote solubility, there is a solubility limit according to hydrolysis degree. In this study, PVA solutions at various concentrations were obtained by mixing fully hydrolyzed PVA1500 and water. Solutions were characterized by density, surface contact angle and dynamic viscosity measurements. Then, solvent casting was used to obtain films, and physical and mechanical properties were determined. Tensile test results showed optimum values at 10–12.5 wt.% PVA concentration. Also, vacuum drying changed the mechanical behavior of films significantly at all concentrations. While ultimate tensile stress values almost doubled and modulus values increased approximately three times, elongations critically decreased. Solutions were also subjected to waste carbon fiber (CF)/polyamide 12 (PA12) prepregs for recycling purposes. Lay-up and compression molding processes were applied to produce CF/PA12 composites. It was seen that mechanical results were significantly increased with increasing PVA concentration.

This research study with an extensive literature review represents a comprehensive multi-criteria analysis for optimizing the cutting parameters in the manufacturing of flexible two-phase passive thermal management systems (FTP-TMS) using thermoplastic materials. Recognizing the critical role of thermoplastics in FTP-TMS due to their inherent flexibility and lightweight properties, this research focuses on the precision cutting of polypropylene, polyethylene, and polyvinyl chloride using CO 2 laser technology. The study is structured into three distinct phases. Initially, an experimental setup was conducted to cut 2 mm thick thermoplastic materials with varying power and cutting speed parameters. Subsequently, the SWARA method was employed to weight the criteria, followed by the application of seven different multi-criteria decision-making (MCDM) methods for optimization. The final phase involved a detailed analysis of the outputs, including ranking, correlation, and sensitivity analyses. The findings indicate that cutting polypropylene with a 90 W power setting and a speed of 15 mm s −1 yields the most optimal results. This study fills a significant gap in the existing literature by providing a dedicated analysis for thermoplastics in FTP-TMS manufacturing. The insights gained are pivotal for standardizing manufacturing practices and enhancing the design and fabrication of flexible thermal management solutions, offering substantial benefits to sectors like electronics, aerospace, and automotive industries.

In this study, the growth kinetics of the Fe 2 B layer was investigated and formed on the surface of borided AISI M2 high-speed steel. Boriding treatments carried out by the pack-boriding method were carried out using Ekabor 2 boriding agent at 1,173, 1,273, and 1,373 K for 2, 4, and 6 h. After the boriding processes, the samples were prepared metallographically and their microstructures were examined with the help of backscattered electrons (BE) by scanning electron microscope (SEM). Following SEM examinations, microhardness measurements were carried out from a single sample using 100 g with the Vickers indentation method to understand whether the layer hardness was compatible with Fe 2 B. When the results of the experimental studies are compared with the results of the literature, it has been determined that AISI M2 high-speed steel can be borided and the boride layer formed on the surface is single-phased (Fe 2 B), unlike that formed on many other steel types. After determining that the layer formed on the borided AISI M2 surface is single-phase Fe 2 B, the growth kinetics calculations of this phase were carried out with the help of the Arrhenius equation.

3D-printed truss structures have remarkable potential in the aerospace and weight-critical technologies fields. However, design parameters need to be carefully considered. A low overhang angle or diameter can result in discrepancies. This research presents an approach by examining the effect of strut overhang angle and radius on the mechanical properties of 3-, 4- and 6-strut lattice structures under compressive loading. 1.6- and 2.4-mm diameter struts were designed with 45°, 50°, 55° and 60° overhang angle strut lattices. Experiments were simulated and compared with test results for each parameter. Even if joint regions have little effect on specimens’ density, it has a remarkable effect on mechanical properties of the specimen. To simulate this, many studies were investigated to simulate joint regions. The study’s goal is to deepen the understanding of how design variations in strut lattice structures influence their energy-absorbing characteristic and mechanical behavior, using a combination of static tests and finite element analysis for validation. This insight is crucial for optimizing lattice design to balance weight, strength, and energy-absorbing capacity effectively. The experimental test result and numerical result showed rather good agreement. It is observed that joint regions, overhang angle, and diameters were the main parameters affecting specimens’ mechanical behavior.

Low carbon steels are frequently preferred in the automotive industry. The most preferred welding method in vehicle body manufacturing is resistance spot welding (RSW). In this study, RSW joints of DC04 and HRP6222 steels were carried out at two different electrode forces (2.1 kN, 2.4 kN) and three different welding currents (4 kA, 6 kA, 8 kA). The effects of different welding parameters on microstructure, tensile shear force, failure mode and microhardness were investigated. So, the focus was on optimizing the welding parameters. As a result, the RSW process caused the formation of three different regions in the microstructure (the base metal, the heat affected zone and the weld metal). It was observed that the tensile shear force increased as the welding current and electrode force increased. After the tensile shear tests, two different failure modes occurred (interface and pull-out type). Hardness values showed a linear relationship with tensile shear force results. In addition, a significant increase in hardness values was observed from the base metal to the weld metal in all welding parameters.