Fabricantion Of Particle Reinforced Al Matrix Composites And Study On Microstructure And Properties

With the development of science and technology, the performance of material was required more and more. The practical application could not be met by homogenous material so that leaded to metallic matrix composites developed quickly. Particulate reinforced Aluminum matrix composites were attracted the most attention specially due to that had the merit of aluminum base matrix,particulate reinforced and low cost and also could be processed by hot rolling and other tradition metal processing.Five kinds of composites of 4μm 43%Al2O3/2024,1μm 30%Al2O3/2024,4μm 40%SiCp/2024,4μm 40%AlNp/6061 and 0.4μm 20%Al2O3/6061 were processed respectively by squeeze casting and then the annealing treatment and ageing treatment were adopt in this study. The thermo physical property and mechanical property of composites were measured through analytical balance,hardmeter,expansion indicator,universal tensile testing. The microstructures were analyzed by scanning electronic microscope (SEM) followed by the relevant influence factors analyzing. The results showed that the microstructure of composites made by squeeze casting method was densification and the particles distributed homogeneously. Compared with the matrix alloy the hardness of composites increased obviously. The result of tensile experiment in normal temperature showed that the strength and hardness of composites after solution and aging treatment increased but the ductility decreased comparing with the annealing treatment. Appearance of fracture which was scanned by SEM showed that broken and stripping was existed in the particles and there were a few dimples in the matrix alloy. The big particles were brittle fracture and the small were spelled. All of material fracture mode showed brittle fracture and the ductility was low in normal temperature.Five kinds of composites of average coefficient of thermal expansion (CTE) were apparently lower than matrix Al alloys and shown a liner rule increasing with the temperature going up. The CTE value of composites after solution and ageing treatment decrease obviously compared with that of annealing treatment. Compared with the ROM, Turner model, Kerner model and Shapery model, the experiment value of 5 composites after annealing treatment waved in the Shapery model and the Kerner model, matching well with the Kerner model. The experiment value of composites after ageing treatment waved in the four models, showing different characteristics with the different types of particle enforcement.