Study Of The Performance Of Al₂O₃ Nanoparticle Reinforced Aluminum Alloy Matrix Composites

The mechanic behavior of Al₂O₃ nanoparticle reinforced aluminuma alloy matrix composites during hot compression deformation conditions was studied by isothermal hot compression on G1eeble-1500b hot simulation machine. The mechanical properties of deformation nanometric Al₂O₃ particle reinforced aluminum alloy matrix composites under different heat treatment condions were investigated by metallographic analysis,durometer , wear test and tensile test. The experimental results are as follows:1) the flow stress of Al₂O₃ nanoparticle reinforced aluminuma alloy matrix composites increases with increasing strain rate and decreases with increasing temperature, so it was positive strain rate sensitive materials, and the exponential relationship between flow stress and strain rate shows the hot extresion of the composites was controlled by activation energy;2) the grain size of Al₂O₃ nanoparticle reinforced aluminuma alloy matrix composites increases with increasing temperature and decreases with increasing strain rate in the conditions of the deformation temperature range 320～440℃and the strain rate range 0.01～1s-1, and there are significant dynamic recrystallization at the deformation temperature 480℃and severe intergranular fracture at the deformation temperature 480℃and the strain rate 1s-1;3) according to the model of Sellars and Tegartthe, the constitutive equation of the composites is obtained in the following form:ε&=1.66×1012[sinh(0.013σ)]6.18exp(-1.77×105/RT);4) the hardness and wear performance of deformation nanometric Al₂O₃ particle reinforced Al matrix composites were found to be greatly enhanced after thermal treatment, and as comparison, after 510℃×3h quenching and 120℃×24 aging, the wear performance of composites had the best performance, but the affect of the thermal treatment on tensile strength and plasticity of the composites is negative;5) the fracture mechanism of nanometric Al₂O₃ particle reinforced aluminum alloy matrix composites was dimple rupture, and after heat treatment, the fracture mechanism of nanometric Al₂O₃ particle reinforced aluminum alloy matrix composites turns to be brittle fracture.