应变量对锻造Mg-Gd-Y-Zn-Zr合金显微组织和力学性能的影响

Influence of strain on microstructure and mechanical properties for forged Mg-Gd-Y-Zn-Zr alloy

采用多向锻造工艺成功制备出应变量分别为1. 5和2. 1的两个Mg-Gd-Y-Zn-Zr合金样品,并利用光学显微分析、扫描电子显微分析、XRD宏观织构测量以及力学性能测试等手段,着重研究了不同应变量对锻造样品显微组织和力学性能的影响。结果表明:随着应变量从1. 5增加至2. 1,样品不同区域的组织都因再结晶体积分数的提高而得到明显细化,但其平均再结晶晶粒尺寸一直保持在2. 6μm左右,与样品应变量和区域无关;应变量为2. 1时的样品心部具有最高的综合力学性能,其屈服强度、抗拉强度和伸长率分别为263 MPa、346 MPa和18. 6%,其优异的综合力学性能应该归功于大应变导致的晶粒细化和随机晶体取向的共同作用。

Two Mg-Gd-Y-Zn-Zr samples with strain of 1.5 and 2.1 were successfully fabricated by multi-direction forging process,and the influences of different strains on the microstructure and mechanical properties of forging samples were investigated by the optical microscopy,scanning electron microscopy,XRD macrotexture measurement and mechanical property test.The results show that with the increasing of strain from 1.5 to 2.1,the microstructure in different regions of sample is refined to a large extent due to the increase of recrystallization volume fraction.However,the average size of recrystallization grains in such microstructure is kept around 2.6μm independent of strain and region of sample.Furthermore,the central part of sample with strain of 2.1 occupies the highest comprehensive mechanical properties with the yield strength of 263 MPa,the tensile strength of 346 MPa and the elongation of 18.6%,respectively,and its remarkable mechanical properties can be ascribed to the comprehensive effect of grain refinement and random crystal orientation resulted from the high strain.