Investigating the Effect of Reinforcing Particles Size and Content on Tensile and Fatigue Properties of Heat-Treated Al7075-SiC Composites Fabricated by the Stir Casting Method

Metal matrix composites with superior mechanical and fatigue properties are in great industrial demand. In the present study, a two-step stir casting method and T6 heat treatment were implemented to fabricate Al7075-SiC composites. SiC particles of varying content and size (nano, submicron, and micron) were added to the Al7075 matrix. Tensile strength and fatigue properties of the fabricated composites were then evaluated. Results showed that addition of SiC particles into the matrix increased tensile and fatigue strength. In contrast, the elongation of samples decreased. Samples reinforced with nanoparticles showed better tensile and fatigue properties compared with the other composites (submicron and micron reinforcement). It was observed that Al7075 reinforced with 1% weight percentage of SiC nanoparticles improved the ultimate tensile strength and fatigue strength of pure Al7075 samples by 21.33% and 66%, respectively. However, further addition of reinforcing particles above a certain limit resulted in a decrease in tensile strength.