航空电子用Mg_2Si/Al复合材料的热处理

Heat-treatment of Mg_2Si/Al Composites Prepared by Gravity Casting for Aviation Electron

通过重力铸造和等温热处理结合热挤压制备了航空电子用Mg_2Si/Al复合材料,研究了不同等温时间和等温温度下的复合材料的显微组织和力学性能变化,并探讨了其作用机理。结果表明,等温热处理后组织中的Mg_2Si相由多边形小块状向球状或者椭球状转变,且增强相Mg_2Si相随着等温时间延长,球化程度有逐渐增加的趋势;等温不同温度和不同时间的半固态挤压Mg_2Si/Al复合材料的抗拉强度和断口伸长率都高于重力铸造Mg_2Si/Al复合材料;航空电子用Mg2Si/Al复合材料的断裂主要来自基体断裂、初生Mg_2Si相开裂和初生Mg2Si相与基体界面开裂。

Through gravity casting and isothermal heat treatment combined with hot extrusion method,the Mg_2Si/Al composites for aviation electron were prepared and investigated.Effects of different isothermal holding time and isothermal temperature on the microstructure and mechanical properties of the composites prepared were analyzed,and the mechanism was described.The results show that the Mg_2Si phase is converted from small polygonal to spheroidiation or ellipsoid shape after isothermal heat treatment,and the degree of spheroidization is gradually increased with the isothermal time increase.The tensile strength and elongation of semi-solid squeezed Mg_2Si/Al composites are superior to those of gravity casting Mg_2Si/Al composite after different isothermal temperatures and time.The fracture of Mg_2Si/Al composites is characterized mainly by matrix fracture,primary Mg_2Si phase cracking and primary Mg_2Si phase with matrix interface debonding.