锌对Mg-6Al合金显微组织和力学性能的影响

Effect of Zn on Microstructure and Mechanical Properties of Mg-6Al Alloy

采用光学显微镜、万能材料试验机、X射线衍射仪、电子探针和扫描电镜等手段分析了Mg-6Al-xZn合金的显微组织和力争性能。结果表明:加入不同锌含量的Mg-6Al合金显微组织主要由α-Mg、β-Mg_(17)Al_(12)和τ-Mg_(32)(Al,Zn)_(49)相组成;随着锌含量的增加,合金中第二相的数量增多,晶粒逐渐细化;Mg-6Al-6Zn合金具有最高的室温抗拉强度和韧性,当锌含量超过6%后合金晶粒粗化,综合力学性能下降。

The microstructure and mechanical properties of Mg-6Al-xZn alloys were investigated by means of optical microscope,universal tester,X-ray diffractometer,electron probe microanalyzer and scanning electron microscope.The results indicate that the microstructure of Mg-6Al-xZn alloys with different Zn contents was mainly composed ofα-Mg,β-Mg_（17） Al_（12） phase andτ-Mg_（32）（Al,Zn）_（49） phase.With the increasing of Zn content,the amount of the second phase in the alloys gradually increased and the grains were refined.The Mg-6Al-6Zn alloy had the highest tensile strength at room temperature and the highest toughness.When the content of Zn was more than 6wt%,the universal mechanical properties of the alloy decreased with the grain size increasing.