Study Of Double Phase Reinforcements Aluminum Matrix Composites

Though the properties of Al matrix composites are better than other common materials, their cost is high. It is hard to be used in application areas ranging from aerospace to civil industries. It is urgently needed to fabricate the Al matrix composites with low-cost and excellent properties using simple process.Solid-mixing method and liquid-packing method to fabricate theα-Al2O3/Al matrix composites are used in this study. Effects on microstructures and properties of theα-Al2O3/Al matrix composites are studied by two different methods of adding the RE. The effect of different RE contents on microstructures and properties of theα-Al2O3/Al matrix composites are discussed. The results indicated that the hardness and the wear resistance of particle reinforced aluminum matrix composites made by liquid-packing method are higher than that manufactured by solid-mixing method. The composites with proper RE Ce adding can improve the microstructures and properties of theα-Al2O3/Al matrix composites. Based on this observation, two key problems are investigated further in this paper.Firstly, the low-costα-Al2O3 andγ- Al2O3 particulate fillers are used as reinforcementsα-Al2O3+γ-Al2O3/Al matrix composites are fabricated successfully by powder metallurgy. When an adequate amount of the mixture of 50%α- Al2O3 and 50%γ- Al2O3 fillers are added into composites,α-Al2O3 andγ- Al2O3 particles are distributed uniformly in the matrix andα-Al2O3 andγ- Al2O3 grains are in mesh well. The hardness and the wear resistance of particle reinforced aluminum matrix composites are increased obviously. Base on this result, a new model for analyzing particle reinforcement mechanism ie. Double phase reinforce model, is suggested.Secondly, the reinforcements ofα-Al2O3 particles with surface covered by Re are fabricated. Using this surface modified reinforcement together withγ- Al2O3 particles and Al matrix, Al matrix composites with good microstructures and properties are successfully fabricated. The addition of proper amount of RE (0.5%) can improve the interfacial bonding betweenα-Al2O3 reinforcement and Al matrix, which can improve structures and mechanical properties of double phase reinforced Al matrix composites.