Atomistic insights into the effect of heat treatment on the mechanical properties of SiCp/Al

YN Xiong and Y Shi and XY Zhang and CC Yin and X Luo and J Wang and LY Sun, JOURNAL OF ALLOYS AND COMPOUNDS, 1040, 183455 (2025).

DOI: 10.1016/j.jallcom.2025.183455

Heat treatment is commonly employed after fabrication of metal matrix composites to enhance their physical and mechanical properties. Different heat treatment methods exert a significant impact on the mechanical behavior of composites. Using molecular dynamics simulations, we investigate the tensile loading behavior of SiCp/Al composites under various heat treatment conditions. We found that the accumulated residual stresses and microdefects introduced by heat treatment play a critical role on the yield strength and plastic evolution of the composites. Higher temperature differences and increased heat treatment cycles lead to more residual stresses and microdefects accumulation, resulting in decreased ultimate yield strength and earlier onset of yielding. Insufficient relaxation during heat treatment can lead to a lower ultimate tensile strength but a higher flow stress. At strain rates below a threshold (approximately 1 x109 s-1), strain rate sensitivity is reduced from 0.0295 to 0.0009 after heat treatment, evidenced by less pronounced variations in yield stress with strain rate at relatively low strain rates. The accumulation of microdefects and residual stress concentration near the reinforcement-matrix interfaces after heat treatment can serve as the initiation sites for plastic deformation and partly alleviate the mechanical loading.

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