The Characteristics of Alumina Particle Reinforced Pure Al Matrix Composite

$Al_2O_3$ is widely used as the reinforcing additive in the metal matrix composites. The influence of $Al_2O_3$ particle size on the density, hardness, microstructure, yield stress, compression strength, and elongation of the sintered $Al-Al_2O_3$ composites were investigated. In the present study, 10 wt% of $Al_2O_3$ powder with three different particle sizes (3, 12 and 48 μm) were used in the production of the samples. Powder metallurgy technique was utilized to obtain more homogeneous $Al_2O_3$ distribution across the composites. The samples were cold pressed at 440 MPa, and sintered at 550C for 45 min. Results showed that the relative density of the composite was initially increased with decreasing particle size. However, it was decreased with further particle size reduction. It was also pointed out that the mechanical properties of the specimens were increased with decreasing particle size. The grain size and particle distribution homogeneity was decreased with raising the particle size.