Study on the effect of heat treatments on microstructure and mechanical properties of nano SiC reinforced AlSi7Mg alloy

Abstract This paper investigated the influence of heat treatment on the microstructure evolution and mechanical performance of nano SiC-enhanced AlSi7Mg alloy fabricated using the laser powder bed fusion technique. After heat treatment, the grain size of the specimen increases significantly, the reticular structure is gradually broken, and Si is gradually precipitated after annealing. With increasing annealing temperature, elongation increases, while the yield strength decreases. After solution-aging heat treatment, the grain distribution is more uniform, the grain size increases slightly, and larger-sized Si and Mg2Si particles precipitate. As the solution temperature increases, the yield strength and the tensile strength of the samples show an increase followed by a decrease, while the trend of elongation is opposite. Both heat treatments exhibit ductile fracture as the predominant damage mode.