Materials Science Forum Vol. 1194

Abstract: Friction Stir Processing (FSP) is an advanced solid-state surface modification technique used to enhance the microstructural and mechanical behavior of metallic materials, particularly aluminum alloys. Recently, High-Entropy Alloys (HEAs) have emerged as promising reinforcement materials due to their high strength, thermal stability, and corrosion resistance. Although multiple studies have explored FSP with conventional reinforcements, the integration of HEAs into the stir zone remains limited. This study examines the influence of tool geometry, processing parameters, and reinforcement strategies in FSP while evaluating the feasibility of incorporating HEAs into aluminum matrices. The role of finite element analysis (FEA) in predicting temperature distribution, material flow, and stress evolution is also discussed. The study identifies research gaps and emphasizes the need for experimental validation of HEA-reinforced FSP systems to develop high-performance aluminum-based surface composites.

Abstract: A non-Equi atomic W₂₄Ta₂₄Nb₂₄Cr₁₆Al₁₂ high entropy alloy (HEA) was designed based on thermodynamic calculations in order to obtain a single body-centered cubic (BCC) structure. The HEA was further fabricated by using the vacuum arc melting technique. The structural analysis of the HEA revealed the formation of a single BCC phase with the lattice parameter of 3.259Å. The micrograph of the HEA revealed dendritic structure with inter-dendritic segregations. The thermal analysis confirmed that the HEA is quite stable at high temperatures up to 1600°C. The thermal expansion of the HEA was also very low at 1100°C. The mechanical property such as the hardness of the HEA at room temperature, was quite high at 467 ± 20 HV₀.₅. The HEA was further heat treated at a very high temperature (1000°C) and the structural and mechanical properties were evaluated. The heat-treated HEA shows excellent structural stability as no secondary phases were formed in those samples. The mechanical property such as hardness of the HEA was increased continuously on increasing the heat treatment duration, which shows that the current alloy is highly preferable for possible high-temperature applications.

Abstract: In the present study, a two-dimensional steady state laminar flow model was developed using fluent software in order to investigate the possibility of achieving Mg/Al cladding using a horizontal twin roll caster. The effects of parameters such as upper and lower inlets casting sequence, solidification length on the temperature field at the bond interface and outlet thickness direction were investigated. The feasibility of the model was verified by combining with experiments. The results show that the molten A5052 alloy with a high melting point is more suitable to be cast by the lower roll at the roll speed of 9 m/min and the roll gap of 5 mm. The temperature of the A5052 and AZ91 near the bond interface of the clad strip can be controlled by the solidification length. Numerical simulations can provide guidance for the optimal casting process parameters.

Abstract: A cold roll-bonding (CRB) process is applied to fabricate a multi-layer Al sheet using AA5052 and AA6061 alloys. The rolling is performed for four-layer sheets in which AA5052 and AA6061 sheets are stacked alternately after surface treatments such as degreasing and wire brushing. The 4-layer sheets with a thickness of 8 mm were roll-bonded to 2 mm by rolling at total reduction of 75%. The as roll-bonded Al sheets are then processed by natural aging (T4) and artificial aging (T6) treatments. T4 and T6 treated specimens showed a typical recrystallization structure over all regions of AA5052 and AA6061. The average grain diameter of T4 and T6 specimens was about 15 μm, which is almost the same. In addition, the Al sheet showed a heterogeneous hardness distribution in thickness direction. After the aging treatments of T4 and T6, the strength rather decreased and the elongation increased. It is found that new multilayer Al sheets made of AA6061 and AA5052 alloys, exhibiting various mechanical properties can be fabricated through the CRB and subsequent aging treatments.

Abstract: This study examines the significant potential of used tea powders (UTP) as a sustainable additive for recycling aluminium alloy 5083. By remelting and recasting aluminium chips with varying quantities of UTP (0 g, 2 g, 4 g, and 6 g), this research aims to provide insights into the microstructural, mechanical, and surface characteristics of the resulting materials. Notably, the recycled aluminium exhibited smoother surfaces in comparison to the bulk alloy, particularly with moderate UTP additions of 2 g to 4 g, which effectively reduced surface roughness. The highest hardness recorded was 57.66 HV for the recycled aluminium without any additives; however, the initial addition of UTP led to a decrease in hardness, which interestingly stabilised at higher concentrations. Microstructural analysis indicated refined grain structures and the formation of carbon- and oxygen-rich phases when optimal levels of UTP were employed. Conversely, higher quantities resulted in some degree of agglomeration and porosity. In conclusion, UTP demonstrates considerable promise as an environmentally friendly modifier that enhances microstructure and supports sustainable practices in aluminium recycling.

Abstract: This study presents a finite element investigation of the vibration characteristics of a laminated carbon fiber reinforced polymer (CFRP) composite plate with a centrally surface-bonded piezoelectric (PZT-5H) patch under classical boundary conditions. A square CFRP plate of dimensions 300 × 300 × 3 mm with a [0/90/0/90] layup is analyzed with and without an active piezoelectric patch, considering clamped–clamped–clamped–clamped (CCCC), clamped–free–clamped–free (CFCF), clamped–free–free–free (CFFF), and simply supported–simply supported–simply supported–simply supported (SSSS) boundary conditions. Linear piezoelectric theory and steady-state harmonic excitation are employed using Abaqus/CAE 2025 Learning Edition. Modal characteristics are obtained from the first six natural frequencies, while harmonic response is evaluated in terms of peak out-of-plane displacement at the plate center under combined mechanical loading and open-loop electrical actuation. The results demonstrate that the presence of the PZT patch induces boundary-condition-dependent modifications in both natural frequencies and harmonic response amplitudes. For highly constrained configurations (CCCC and SSSS), the active PZT patch leads to a reduction in peak harmonic displacement, whereas for less constrained cases (CFCF and CFFF), a slight amplification of the response is observed. These findings highlight the strong coupling between structural boundary conditions and piezoelectric actuation effectiveness, and they establish a validated baseline for future investigations involving closed-loop control, multi-patch configurations, and data-driven optimization strategies.

Abstract: Growing environmental awareness and the challenges posed by climate change have driven the development of sustainable composites to reduce dependence on fossil resources and mitigate ecological impacts. Conventional composites, despite their high mechanical performance, are constrained by greenhouse gas emissions and limited recyclability, motivating the adoption of “green composites” based on natural fibers, recycled constituents, and bio-based resins. This study presents a sustainable sandwich composite integrating flax fibers, a bio-based epoxy matrix, and a recycled PET foam core. Flexural performance was evaluated through finite element analysis (FEA) in ANSYS Workbench and validated by three-point bending tests. The results show that the 3C specimen achieved a maximum load of 579.92 N, with a deviation of 4.2% from simulation at 6 mm deflection, and all tested specimens exhibited discrepancies below 5%. These findings confirm the suitability of the developed composites for structural applications such as UAV wings, aligning high mechanical performance with environmental sustainability.

Abstract: Polybutylene succinate (PBS) and rice flour (RF) biocomposites containing 10 and 20 parts per hundred resin (phr) of RF were successfully fabricated. The effects of epoxidized natural rubber (ENR-50) at loadings of 0, 1, 5, and 10 phr on the interfacial compatibility and mechanical performance of PBS/20 phr RF composites were examined. The compatibilizing effectiveness of 3-aminopropyl-triethoxysilane and ENR-50 was also evaluated comparatively. The composites were first blended using a two-roll mill to achieve homogeneous mixing and then molded into test specimens through an injection molding technique. The phase morphology, along with mechanical characteristics such as tensile and flexural properties, impact resistance, and Shore D hardness, was thoroughly evaluated. Incorporating 1 phr ENR-50 resulted in notable improvements in phase compatibility and mechanical properties, with scanning electron microscopy (SEM) revealing reduced surface roughness and enhanced matrix–filler interfacial adhesion. Improvements in impact strength, hardness and modulus values were also observed at this loading. Further increases in ENR-50 content adversely affected flexural strength, flexural modulus, Young’s modulus, and hardness. Comparative analyses showed that the combined use of a silane coupling agent and ENR-50 yielded a more homogeneous phase morphology with superior mechanical properties compared to the addition of either agent alone. These findings demonstrated the synergistic effect of using both compatibilizer types to enhance the performance of PBS/RF biocomposites.

Abstract: This paper discussed various types of pore formers that have previously been applied as porosity enhancers in the NiO YSZ-based planar SOFC anode since porosity plays an important role to easily diffuse the fuel, thus increasing the triple-phase boundary area and electrochemical performance. Therefore, this study emphasized reviewing recent experiments to find out more effective pore formers by making a comparison between natural (rice starch), polymer-based (PMMA), and carbon-based materials such as graphite. It has been found that rice starch at 7 vol.% gives 10.05% porosity at 1000 °C while activated carbon graphite gives only 4.25%. PMMA shows the highest porosity of 41% at 30 vol.% at 250 °C with almost no residue left behind as proven via TGA analysis which showed only about 0.7%. These findings highlight not only the benefits but also the compromises of each approach, whether in terms of residue formation, mechanical stability, or processing cost. The review further suggests that hybrid strategies, which combine different poreformers, could offer a more balanced route toward improved microstructures. Finally, future directions are outlined, with emphasis on nanostructured agents, scalable fabrication methods, and techno-economic considerations to support the commercial adoption of SOFC technology.