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On the material properties of the increasingly high demand for the development of modern science and technology , making a single material is difficult to meet the actual requirements , which has contributed to the rapid development of metal matrix composites . Particle reinforced aluminum matrix composites both advantages of the aluminum matrix and enhanced the advantages of the particles , and the low-cost , simple preparation , but also can be used the hot extrusion traditional metal processing processing , thus attracting much attention . This article by squeeze casting method were prepared respectively of 4μm of 43% Al2O3/2024, 1μm 30 % Al2O3/2024 of of 4 μm 40 % SiCp/2024 of 4 μm , 40% AlN/6061, 0.4μm , 20% Al2O3/6061 5 kinds of composite materials, and the annealing and aging treatment . Using an analytical balance , micro hardness tester , thermal expansion tester , universal tensile machine and scanning electron microscopy and other means to test the mechanical properties of the composites and thermophysical properties and microstructure observation , followed by an analysis of the related factors . The results show that , squeeze casting prepared composite tissue dense , uniform distribution of particles . Relative to the matrix alloy , the hardness of the composite material is increased significantly . Composite tensile tests found that at room temperature , compared to solution and aging state and annealed to rise due to aging strengthening effect , strength , plasticity decreases . The SEM fracture observation that stretch composite particles crushing and peeling small number of dimples and tear ridge matrix ; the large particles brittle fracture small particles flaking fracture mode of material overall performance brittle fracture, several composite materials at room temperature plastic are lower . The five kinds of aluminum-based composite material has an average coefficient of thermal expansion (CTE) was significantly lower than the substrate alloy , and increases as the temperature rises , the substantially linear variation of ; after solution and aging of the composite material in thermal expansion coefficient compared to annealed reduced. By mixing Law ( ROM ) , Turner, model , Kerner model and Shapery model predictive value comparison analyzes the measured values ??of the five kinds of composite material after annealing is mainly in the lower limit value of the model Shapery Kerner between models fluctuations with Kerner match the model predictions ; solution and aging the composite measured values ??fluctuate between the four models , each have their own characteristics composites because of their enhanced body types different .
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