挤压复合AZ91-(SiC_(P)/AZ91)复合板材显微组织和力学性能EI

在300,350,400℃下成功通过挤压复合法制备多层AZ91-(SiC_(P)/AZ91)复合板,探究AZ91-(SiC_(P)/AZ91)复合板中SiC_(P)/AZ91复合材料层和AZ91层的显微组织演变、界面的演化机制和力学性能变化规律。结果表明:热挤压复合中,AZ91-(SiC_(P)/AZ91)多层复合板中合金层发生完全动态再结晶,晶粒细化,合金组织随挤压温度的升高更均匀,而且外层合金层比内层合金层晶粒尺寸略大;SiC_(P)/AZ91复合材料层同样发生完全动态再结晶,晶粒尺寸小于合金层,随着挤压温度的升高,SiC_(P)的分布更加均匀;不同挤压温度下AZ91-(SiC_(P)/AZ91)复合板合金层与复合材料层界面均未出现明显的分层以及开裂现象;AZ91-(SiC_(P)/AZ91)复合板的室温力学强度位于AZ91合金与SiC_(P)/AZ91复合材料之间,SiC_(P)/AZ91层中SiC_(P)与基体界面脱粘是导致复合板材失效的主要原因。

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

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