Double scale（nano

micro）Al2O3particle reinforced aluminum matrix composites were prepared by powder metallurgy combining with vacuum hot pressing sintering method

and the microstructure

density

hardness and wear resistance of the composites prepared were analyzed.The results show that two-scale composite reinforcement is uniformly distributed in the matrix with the absence of agglomeration.With micron particle content more than 20%

the holes in the composites prepared are increased.Two-scale composites with particles in size of 4%30nm and 15%75μm exhibit desirable performance

and its hardness is increased by 70%

and wear resistance is increased by 7.31%

compared with those of Al-Si matrix.Wear resistance of two-scale hybrid particulate composites is higher than a single nanometer or micrometer particulate reinforced composites

and the main wear mechanism is characterized by adhesive wear

plough wear and abrasive particle wear.