The production of al based composites reinforced with Al2O3 by mechanical alloying

In this study, Al2O3 particle-reinforced Al based metal matrix composites (MMC?s) were produced by mechanical alloying (MA) tecnique. The effect of mechanical alloying process on properties of composite materials was investigated. In the produced composites, the ratio of reinforcing material of Al2O3 particle was chosen as 5%, 10% and 15% by volume ratio. Mechanical alloyed Al alloy and Al-Al2O3 composite powders were cold compacted at 200, 300, 500 and 700 MPa, respectively. Specimens were then sintered at 600oC for 3 h under Ar atmosphere in a tube furnace. The morphology and the structure of the prepared powder, which change with milling time, were evaluated using scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques, respectively.The results showed that, more homogenous dispersion of Al2O3 particles was obtained in Al matrix with increasing the milling time in planetary type ball mill. However, the density of composites decreased with increasing reinforcement volume fraction but the porosity and hardness increased with inreasing particle content.