Mg-10Er-2Zn-0.6Zr合金的组织及力学性能

Microstructure and Mechanical Properties of Mg-10Er-2Zn-0.6Zr Alloy

采用光学显微镜、X射线衍射仪(XRD)、扫描电镜(SEM)和力学试验等研究了Mg-10Er-2Zn-0.6Zr合金的组织和力学性能。结果表明,铸态Mg-10Er-2Zn-0.6Zr合金主要由树枝状α-Mg基体以及分布于枝晶间的长周期结构相和Mg_3(Er,Zn)相组成;合金经过500℃×20h固溶后,铸态合金中LPSO相和Mg_3(Er,Zn)相消失,而在晶界处生成WMg_3Er_2Zn_3相;随后炉冷至400℃,α-Mg晶内析出呈平行排列且贯穿晶粒的条纹状LPSO相结构。拉伸条件下,固溶态合金具有最佳的力学性能,其屈服强度、抗拉强度和伸长率分别为117 MPa、227 MPa、17.9%。与拉伸性能相比,压缩条件下合金表现出更优的力学性能。

The microstructure and mechanical properties of the Mg-10Er-2Zn-0.6Zr alloy were investigated by means of optical microscope（OM）,X-ray diffraction（XRD）,scanning electron microscope（SEM）and mechanical tests.The results reveal that as-cast Mg-10Er-2Zn-0.6Zr alloy is mainly composed ofα-Mg dendrite and interdendritic long period stacking ordered（LPSO）phases and Mg3（Er,Zn）phases.After solution treatment at 500℃for 20 h,both LPSO phase and Mg3（Er,Zn）disappear and in turn a new W（Mg_3Er_2Zn_3）phase can be observed along the grain boundaries.During the following cooling in the furnace to 400 ℃,the LPSO lamella structure is parallel to each other precipitated within and throughout theα-Mg grains.The solution-treated alloy exhibits the desirable mechanical properties,where yield strength,tensile strength and elongation reach 117 MPa,227MPa and 17.9%,respectively.However,the compressive properties are superior to those of tensile ones.