Mg-xZn-5Al镁合金显微组织及力学性能的研究

Study on Microstructure and Mechanical Properties of Mg-xZn-5Al Magnesium Alloy

摘要: 采用亚快速凝固方法制备Mg-xZn-5Al (x = 5 ,8, 11, 14 wt%)镁合金，并利用OM、XRD、SEM和万能拉伸试验机等手段研究了Zn含量的变化对合金的显微组织和力学性能的影响。结果表明，随着Zn含量的增加，实验合金显微组织主要由α-Mg + Mg₃₂(Al,Zn)₄₉转变为α-Mg + Mg₃₂(Al,Zn)₄₉ + MgZn；抗拉强度和伸长率均呈现先增加后减小的趋势，屈服强度不断增加，当Zn含量为11%时，合金综合性能最佳，室温屈服强度、抗拉强度和延伸率分别为120 MPa、186 MPa和6.1%。其拉伸断裂方式为由准解理断裂与局部韧性断裂的混合断裂方式。

Abstract: Mg-xZn-5Al (x = 5, 8, 11, 14 wt.%) Magnesium alloy was prepared by the sub-rapid solidification method. The effect of Zn content on the microstructure and mechanical properties of the alloy was investigated by OM, XRD, SEM and universal tensile testing machine. The results show that the mi-crostructure of the experimental alloy is mainly changed from α-Mg + Mg₃₂(Al, Zn)₄₉ to α-Mg + Mg₃₂(Al, Zn)₄₉ + MgZn with the increase of Zn content. The comprehensive mechanical properties of magnesium alloys which contained 11% content magnesium is best in this experiment, ultimate tensile strength and elongation of the alloy at peak hardness reach 120 MPa,186 MPa and 6.4% at room temperature, respectively. The tensile fracture mode is the mixed fracture mode consisting of the quasi-cleavage fracture and the local ductile fracture.