Microstructure and mechanical properties of AZ91-(SiCP/AZ91) clad plate fabricated by extrusion

Multilayered AZ91-(SiCP/AZ91) clad plates were fabricated at 300, 350 ? and 400 ? successfully by extrusion. The microstructure evolution, bonding interface and the mechanical properties of the AZ91-(SiCP/AZ91) clad plates were investigated in detail. The results show that grain of both of the AZ91 layer and SiCP/AZ91 layer are refined due to the dynamic recrystallization (DRX) during the extrusion processes and the SiCP/AZ91 layer processes much finer grain size. The SiCP distribution of SiCP/AZ91 layer is improved with increasing of extrusion temperature. No obvious delamination is observed in the AZ91-(SiCP/AZ91) clad plates fabricated at different temperatures. The metallurgical bonding of the interface between AZ91 and SiCP/AZ91 basically occurs in the extrusion die. The room-temperature strength of the AZ91-(SiCP/AZ91) composite lies between the AZ91 alloy and the SiCP/AZ91, corresponding well with the rule of mixture (ROM). The inadhesion of the SiCP in the SiCP/AZ91 layer is the main reason for the failure of the AZ91-(SiCP/AZ91) clad plates during tensile test.