(北京有色金属研究总院，北京 100088)
摘 要: 利用XRD、OM、SEM、TEM测试技术和室温拉伸试验研究均匀化热处理对Mg-7Gd-3Y-1Nd-1Zn- 0.5Zr(质量分数，%)合金显微组织及力学性能的影响。结果发现，铸态组织主要由α-Mg、(Mg, Zn)3RE相和堆垛层错组成，热处理使(Mg, Zn)3RE部分回溶、晶界附近的堆垛层错消失，但沿着晶界产生了块状14H型长周期堆垛有序(LPSO)相。铸态合金的抗拉强度、屈服强度和伸长率分别为187 MPa、143 MPa和3.1%；而经均匀化热处理后合金的抗拉强度、屈服强度和伸长率分别为229 MPa、132 MPa和7.2%。
关键字: 镁合金；长周期堆垛有序相；堆垛层错；显微组织演变；力学性能
（Beijing General Research Institute for Non-ferrous Metals, Beijing 100088, China）
Abstract:X-ray diffraction (XRD), optical microscopy (OM), scanning electronic microscopy (SEM), transmission electron microscopy (TEM) and tensile tests at room temperature (RT) were performed to investigate the effect of homogenization on microstructure evolution and mechanical properties of Mg-7Gd-3Y-1Nd-1Zn-0.5Zr (mass fraction, %) alloy. The results indicate that the microstructure of the as-cast alloy is composed of α-Mg, (Mg, Zn)3RE phase and stacking fault (SF), the homogenization results in the disappearance of (Mg, Zn)3RE phase and stacking fault (SF) as well as the emergence of 14H-type long-period stacking ordered (LPSO) phase. The ultimate tensile strength (UTS), yield strength (YS) and elongation of the as-cast alloy are 187 MPa, 143 MPa and 3.1%, and the UTS, YS and elongation of the as-homogenized alloy are 229 MPa, 132 MPa and 7.2%, respectively.
Key words: magnesium alloy; long-period stacking ordered (LPSO) phase; stacking fault; microstructure evolution; mechanical properties
