The Effect Of Aging And Prestretching On Microstructure And Properties Of SiCp/6092Al Composites

Si C particle reinforced Al matrix composites(Si Cp/Al MMCs) offer many advantages, such as high specific strength and specific modulus, good dimensional stability and isotropic properties and lower cost which made them popular in various industries. Powder metallurgy(PM)technique is a common method for the fabrication of Si Cp/Al with high compactness and uniform distributed Si Cp. The Si Cp content and the interfacial reaction could be well controlled in the fabrication of Si Cp/Al by PM. In this study, Si Cp/6092 Al was fabricated by PM technique. The effect of heat treatment on structure and mechanical property of Si Cp/6092 Al by OM, XRD, SEM, TEM, DSC, hardness measurement and tensile tests. The main innovation results are as follows:(1) The strength of extruded rod composite was higher when the aging temperature was 170°C than that was 150°C and 190°C, at the same time, when the aging temperature was 170°C the composite had best aging strength when the aging time was set for 2 h, the extensibility of the composite aged for different time changed slightly. The strength of extruded strip and rod both changed slightly as aging time changed.(2) The strength of extruded strip changed as aging time changed when the aging temperature was 170°C, and it raised when the time increased initial, When the time further increased, the strength became lower, moreover, the strength of extruded strip reached maximum when the aging time was 2 h. On the other hand, when the aging time was 2 h and 24 h, the fracture mechanisms of the composite was ductile fracture, and it changed to ductile fracture and particle fracture mixed when the time was 6 h.(3) The Si Cp/6092 Al composite was dealt with T6 for 6 h after prestretching for 0%, 2%, 3%, and 5%, respectively, the UST almost unchanged, and the YS increased as the deformation quantity increased. The ductility of the composite reduce after prestretching, when the deformation quantity was 2%, the strength of the composite was maximum and the ductility was better comparing with others. On the other hand, when the deformation quantity was 2%, the strength of the composite depressed as the aging time further lengthened. The hardness was maximizing when the aging time was 2 h, it was 165.7 HV, and it was 150.8 HV after aging for 48 h.(4) Comparing with untreated composite, the composite prestretching for 2% has higher hardness after quenching, and the value was 120 HV and 108 HV, respectively. The hardness of untreated and prestretching for 2% composite tended to be stable after they were naturally aged for 400 h, and the values were 143 HV and 129 HV, respectively.