Development of high-performance A356/nano-Al2O3 composites

In this study, a new method was used in stir casting to fabricate nano-Al2O3 particulate reinforced aluminum composites and avoid agglomeration and segregation of particles. Different volume fractions of nano-alumina particles were incorporated into the A356 aluminum alloy by a mechanical stirrer and then cylindrical specimens were cast and tested. The microstructural characterization of the composite samples showed uniform distribution of reinforcement, grain refinement of aluminum matrix, and presence of the minimal porosity. The effects of nano-Al2O3 particle content on the mechanical properties of the composites were investigated. Based on experiments, it was revealed that the presence of nano-Al2O3 reinforcement led to significant improvement in hardness, 0.2% yield strength, UTS and ductility. This combination of enhancement in UTS and ductility exhibited by nano-Al2O3 reinforced aluminum is due to uniform distribution of reinforcement and grain refinement of aluminum matrix. (C) 2009 Published by Elsevier B.V.