In this investigation, the mechanical properties and microstructure of Metal Matrix Composites (MMCs) of Al.6061 alloy reinforced by ceramic materials SiC and Al2O3 with different additive percentages 2.5, 5, 7.5, and 10 wt.% for the particle size of 53 µm are studied. Metal matrix composites were prepared by stir casting using vortex technique and then treated thermally by solution heat treatment at 530 0C for 1 hr. and followed by aging at 175 0C with different periods. Mechanical tests were done for the samples before and after heat treatment, such as impact test, hardness test, and tensile test. Also, the microstructure of the metal matrix composites was examined by optical microscopy before and after heat treatment. The results of this work showed that precipitation of Mg2Si as a secondary phase and improvements in mechanical properties with increase in the percentage of SiC and Al2O3. Also, the results of SiC revealed an improvement in mechanical properties more than for Al2O3 such as hardness, impact strength, yield strength, tensile strength, increasing the plasticity constant (k) and decreasing the strain hardening exponent (n).
