Y含量对Mg-Gd-Y合金组织和性能的影响

Effect of Y content on microstructure and properties of Mg-Gd-Y alloy

研究了稀土元素Y含量对Mg-8Gd合金组织和性能的影响,制备了Mg-8Gd-3Y和Mg-8Gd-7Y两个合金。对两合金的铸态、固溶态和热轧变形态的微观组织进行观察,测试了固溶处理后和热变形后的室温拉伸性能。结果表明:Y含量对Mg-8Gd合金的铸态微观组织无明显影响。经固溶处理后,枝晶偏析被全部消除,Mg-8Gd-7Y合金中有Mg5(Gd,Y)第二相粒子析出,并且出现了粗大的富Y第二相。Mg-8Gd-3Y合金中有Mg3(Gd,Y)第二相粒子析出。室温拉伸试验发现,固溶态和热轧态Mg-8Gd-7Y合金的屈服强度和抗拉强度均高于Mg-8Gd-3Y合金的,但前者的伸长率低于后者的,其原因是高Y含量合金组织中的粗大富Y第二相粒子对塑性变形产生不利影响。

The effect of rare earth element Y content on the microstructure and properties of Mg-8Gd alloy was studied.Two alloys of Mg-8Gd-3Y and Mg-8Gd-7Y were prepared.The microstructures of as-cast,as-solution and hot-rolled alloys were observed,and the tensile properties at room temperature after solution treatment and hot deformation were tested.The results show that Y content has no obvious effect on the as-cast microstructure of Mg-8Gd alloy.After solution treatment,the dendrite segregation is completely eliminated.In Mg-8Gd-7Y alloy,Mg5(G d,Y)second phase particles precipitate,and coarse Y-rich second phase appears.The second phase particles of Mg3(G d,Y)precipitate in Mg-8Gd-3Y alloy.It is found after room temperature tensile tests that yield strength and tensile strength of assolution and hot-rolled Mg-8Gd-7Y alloys are higher than those of Mg-8Gd-3Y alloys.However,the elongation of the former is lower than that of the latter.The reason is that the coarse Y-rich second phase particles in the alloy microstructure with high Y content have adverse effects on the plastic deformation.