双级固溶处理对Mg-4Nd-1Gd-0.3Zn-0.6Zr合金的显微组织和力学性能的影响

Effect of Two-Stage Solid Solution Treatment on Microstructure and Mechanical Properties of Mg-4Nd-1Gd-0.3Zn-0.6Zr Alloy

采用金相显微镜、扫描电子显微镜、透射电子显微镜和电子万能试验机研究了双级固溶温度和时间对Mg-4Nd-1Gd-0.3Zn-0.6Zr镁合金的显微组织和力学性能的影响。结果表明:合金的铸态显微组织主要由α-Mg基体和晶界上的共晶组织Mg_(12)Nd组成。经过不同双级固溶处理后,合金的显微组织由α-Mg基体、Mg_(12)Nd以及时效析出相β'相组成。当双级固溶制度为500℃×20 h+540℃×10 h时,合金的综合力学性能达到最佳。合金的抗拉强度为268.65 MPa,屈服强度为171.28 MPa,伸长率为3.33%。合金的主要断裂方式为混合断裂。

The effects of two-stage solution temperature and time on the micro structure and mechanical properties of Mg-4Nd-1Gd-0.3Zn-0.6Zr magnesium alloy were studied by OM,SEM,TEM and an electronic universal testing machine.The results showed that the micro structure of the as-cast alloy was mainly composed of α-Mg matrix and eutectic Mg_(12)Nd on the grain boundary.After different two-stage solid solution treatments,the microstructure of the alloy was composed of α-Mg matrix,Mg_(12)Nd,and aging precipitates β' phase.When the two-stage solution system was 500 ℃ ×20 h+540 ℃× 10 h,the comprehensive mechanical properties of the alloy was optimal.The tensile strength of the alloy was 268.65 MPa,the yield strength was 171.28 MPa,and the elongation was 3.3 3 %.The main fracture mode of the alloy was mixed fracture.