往复挤压Mg_2Si增强镁铝基复合材料的组织与性能

Effect of Reciprocating Extrusion on the Microstructures and Properties of Mg_2Si Reinforced Mg-Al based Composite

采用石墨型铸造制备了Mg2Si增强镁铝基复合材料,并对该材料进行了不同道次的往复挤压,探讨往复挤压工艺对复合材料组织与力学性能的影响,以寻求改善Mg2Si相形貌并细化其尺寸的新途径。研究表明,往复挤压对该复合材料中Mg2Si相具有较好的破碎作用,而且挤压道次越多,对Mg2Si相的破碎效果越好,Mg2Si相在复合材料中的分布越均匀。往复挤压可显著提高复合材料的室温抗拉强度,但对150℃时材料的抗拉强度提高效果不大。铸态Mg2Si增强镁铝基复合材料在150℃下具有较高的耐热性,抗拉强度为180.5MPa,这主要得益于Mg2Si相的高熔点及其良好的热稳定性。

Mg2Si reinforced Mg-Al based composite was prepared by graphite mouldcasting, and then extruded by reciprocating extrusion in different passes. The effect of reciprocating extrusion on the microstructures, hardness and tensile strength of the composite was investigated in order to seek a new way to refine the Mg2Si phase and improve its morphology. It was found that reciprocating extrusion plays a better role in breaking Mg2Si phase. The more the reciprocating extrusion passes are, the better the breaking effect is, and the more uniform distribution of the Mg2Si phase in the composite is. Reciprocating extrusion can increase the tensile strength at room temperature significantly, while it has little effect on the tensile strength at 150 ℃. The as-cast Mg2Si reinforced Mg-Al based composite has good heat resistance below 150℃ with the tensile strength of 180.5 MPa due to the high melting temperature and good thermal stability of the Mg2Si.