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通过光学显微镜(OM)、X射线衍射仪(XRD)、扫描电镜(SEM)和力学试验,研究了510℃下固溶处理20h所得Mg-15Gd-2Zn-0.6Zr合金的组织结构及力学性能。结果表明,铸态Mg-15Gd-2Zn-0.6Zr合金主要由树枝状α-Mg基体以及分布于枝晶间的(Mg,Zn)_3Gd共晶相组成;固溶处理后,合金相组成未发生变化,而(Mg,Zn)_3Gd相形貌由连续网状转变为不连续岛状,体积分数由19%下降为9%;固溶态合金中未观察到长周期堆垛有序结构的形成。拉伸条件下,固溶态Mg-15Gd-2Zn-0.6Zr合金屈服强度比铸态略有下降,但抗拉强度和延伸率均有较大提高,其屈服强度、抗拉强度和延伸率依次为176 MPa、277 MPa和12.8%,表现出优良的综合力学性能;压缩条件下,铸态和固溶态Mg-15Gd-2Zn-0.6Zr合金的力学性能差异较小,且均优于拉伸条件下的力学性能。
The microstructure and mechanical properties of Mg-15Gd-2Zn-0.6Zr alloy obtained by solution treatment at 510 ℃ for 20h were investigated by OM, XRD, SEM and mechanical tests. The results show that the as-cast Mg-15Gd-2Zn-0.6Zr alloy is mainly composed of dendritic α-Mg matrix and (Mg, Zn) _3Gd eutectic phase distributed between dendrites. After solution treatment, the alloy phase composition does not occur (Mg, Zn) 3 Gd phase transition from continuous mesh to discontinuous island, the volume fraction decreased from 19% to 9%; solid solution alloy was not observed long-period stacking ordered structure formation . Under tensile conditions, the yield strength of Mg-15Gd-2Zn-0.6Zr solid solution decreases slightly compared with the as-cast condition, but the tensile strength and elongation of the alloy are greatly increased. The yield strength, tensile strength and elongation Which is 176 MPa, 277 MPa and 12.8%, respectively. The mechanical properties of the as-cast and solid solution Mg-15Gd-2Zn-0.6Zr alloys are less different under compression than that of the tensile Mechanical properties under conditions.