Studies On Microstructure And Property Of Al+SiC Prefabricated Particles Reinforced Aluminum Based Composites

Aluminum matrix composites reinforced with particles have specialties of high specific strength, high specific stiffness, high elastic modulus, good wear resistance, good corrosion resistance and good high temperature resistance. So they become a kind of potential material for the fields of aeronautics, military affair, automobile manufacture and so on. Because of low cost, good isotropic and wear resistance, aluminum matrix composites reinforced with SiCp and fabricated by semisolid stirring pouring method has received more attention of researchers.The Al+Si C prefabricated particles were obtained by ball-milling SiC particles mixed with aluminum particles in a planetary mill.Aluminum matrix composites reinforced with prefabricated particles(Al+SiCp) were fabricated by semisolid stirring pouring method, and the influence of Al+SiCp and Mg on the microstructure, mechanicalproperties and wear resistance, as well as the strengthening mechanism of T6 heat treatment have been studied in this paper. The conclusions are as follows:With the increase of the volume fraction of Al+SiCp, the vickers hardness, tensile strength and wear resistance is gradually increased,and it’s maximum value increased 12.1%,25.7% and7.6%(at the load of 10N) compared with the matrix alloy,while the grain size and the elongation of the composites gradually decreased.The fracture mechanics of ZL101 alloy is ductile fracture, while the fracture mechanics of Al+Si Cp/ZL101 composite is quasi-cleavage fracture. The wear mechanics of ZL101 alloy is adhesive wear, while the wear mechanics of Al+SiCp/ZL101 composite is abrasive wear.The join of Mg can not only refine the grain and reduce the agglomeration of Al+Si Cp, but also can refine eutectic silicon from acicular to fine particles. The vickers hardness, tensile strength and wear resistance of Al+Si Cp/ZL101-Mg composites are higher than Al+Si Cp/ZL101 composites, but the elongation is less than Al+Si Cp/ZL101 composites. The fracture mechanics of Al+Si Cp/ZL101-Mg composites is cleavage fracture. The wear mechanics of Al+Si Cp/ZL101-Mg composites is abrasive wear.The heat treatment causes the eutectic silicon of Al+Si Cp/ZL101 composites refinement, and the eutectic silicon of Al+SiCp/ZL101-Mgcomposites coarsening. The vickers hardness, tensile strength,elongation and wear resistance of the composites has improved after T6 heat treatment, but the increased range of Al+SiCp/ZL101 composites is larger, and it’s maximum value increased 26.67%,54.44%,5.47% and 10.29%(at the load of 10N) compared with the cast alloy; The tensile strength of Al+SiCp/ZL101-Mg composites after heat treatment first increase and then decrease with the increase of the volume fraction of Al+Si Cp, and the maximum tensile strength is exists when the volume fraction of Al+Si Cp is 2vol.%. The fracture mechanics of ZL101 and ZL101-Mg alloy is ductile fracture after heat treatment, and 1vol.% Al+Si Cp/ZL101 and 2vol.% Al+SiCp/ZL101 composites is quasi-cleavage fracture.Besides, the fracture mechanics of other composites is cleavage fracture.