| Industrialized production of aluminum matrix composites (AMCs) has begun in the United States, Europe and other developed countries, and the material was classified as an important direction of new application materials for 21th century. In order to improve the performance of composite materials, people continue searching the different reinforce phase and ameliorating the fabrication method with followed heat treatment technics. Cryogenic treatment which is seen as an extension of the traditional heat treatment has begun to be used in aluminum matrix composites. In this paper, the influence of cryogenic treatment on mechanical and physical properties of AMCs is researched; the influence mechanism is explained too. the main conclusion are as follows:The number of precipitation phase is increased after cryogenic treatment. The hardness and strength of AMCs are all increased by different degree. The degree of cryogenic treatment has no distinct impact on properties. The volume shrink and crystal turn in cryogenic treatment can close the lacuna and micropore, that can increase the strength of AMCs.The cryogenic treatment alters the dislocation configuration, the matrix exhibit more character of brittle fracture.SiCp can inhibit the expansion of matrix well. The more particles, the lower coefficient of thermal expansion. The inhibition skill of SiCp is lower with the temperature rise, and then the coefficient of thermal expansion will increase.The CTE of AMCs is closed to residual stress and heat mismatch stress, AMCs will happen Plastic deformation in cryogenic treatment. And then the heat mismatch stress will relax, the CTE will reduce with the fall of residual stress.Cryogenic technology reduces the heat mismatch stress which occurs due to mismatch of the thermal expansion coefficient in the interface, thereby the interface thermal resistance will reduce as the degree of lattice distortion relax. So the thermal conductivity of AMCs will increase.
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