15%(volume fraction)SiCp/8009Al metal matrix composites(MMCs)prepared by spray co-deposition were hot-extruded and rolled to investigate the effects of porosity and local SiCp clusters on mechanical properties.The microstructures were examined by using optical microscopy(OM),scanning electron microscopy(SEM),X-ray diffractometry(XRD)and transmission electron microscopy(TEM).The mechanical properties were measured by tensile testing.The experimental results show that lamellar structure is composed of pores and SiCp clusters and can be improved by secondary processing,enhancing mechanical properties. The main strengthening mechanism and fracture behavior of MMCs were discussed too.
The characteristics of microstructures and mechanical properties of the multi-layer spray deposited SiCP/Al-6.5Fe-0.6V-1.3Si,SiCP/Al-8.5Fe-1.3V-1.7Si and SiCP/Al-10Fe-1.3V-2Si composite sheets obtained by rolling after extruding were investigated. The evolution of the grain and phases of these composites during processing were examined,and the influence of the microstructures on the mechanical properties was analyzed. The experimental results show that the ultimate tensile strengths σb of the three kinds of composite sheets are 420,535,470 MPa respectively at room temperature,and 232,285,300 MPa at 315 ℃ and 148,180,200 MPa at 400 ℃. The excellent mechanical properties can be attributed to the high solid solubility,fine grain size,Al12(Fe,V)3Si precipitation particles and the SiC particles. And the composition of the matrix alloy has an obvious effect on the mechanical properties of the as-rolled sheets.
