(1. 西安理工大学 材料科学与工程学院，西安 710048；
2. 广东省科学院 新材料研究所 广东省金属强韧化技术与应用重点实验室，粤港轻合金先进制造技术联合研发中心，广州 510650)
摘 要: Mg-8Gd-4Y-1Zn-0.5Al(质量分数，%)合金铸态试样经均匀化和热挤压后获得挤压板材，分别对均匀化板材和挤压板材进行室温轧制和时效处理；采用OM、SEM、TEM和EBSD分析其微观组织结构，同时测试其硬度和拉伸力学性能，旨在研究上述合金在不同加工工艺下的组织与力学性能演变。结果表明：经室温轧制的均匀化板材组织由等轴晶转变为伴有孪晶的变形晶粒，再结晶处理后转变为静态再结晶晶粒；18R-LPSO结构发生收缩、聚集。峰时效处理后，部分晶粒内部析出大量层错和β′相，规定塑性延伸强度(Rp0.2)与抗拉强度较时效前分别提高24%和23%；室温轧制后，挤压板材的再结晶晶粒尺寸稍微增大，18R-LPSO结构出现不规则的弯曲与分层现象；时效后，板材的规定塑性延伸强度、抗拉强度和伸长率分别达到383 MPa、420 MPa和5.5%。
关键字: 稀土镁合金；长周期堆垛有序(LPSO)结构；轧制；微观组织；力学性能
（1. School of Materials Science and Engineering, Xi’an University of Technology, Xi’an 710048, China;
2. Guangdong-Hong Kong Joint Research and Development Center on Advanced Manufacturing Technology for Light Alloys, Guangdong Provincial Key Laboratory of Metal Toughening Technology and Application, Institute of New Materials, Guangdong Academy of Sciences, Guangzhou 510650, China）
Abstract:The as-cast samples of Mg-8Gd-4Y-1Zn-0.5Al (mass fraction, %) alloy were homogenized and hot-extruded to obtain extruded sheets. And then, the homogenized and extruded sheets were rolled at room temperature and aged, respectively. The microstructures and phase compositions of the samples were analyzed by OM, SEM, TEM and EBSD. Meanwhile, the hardness and tensile mechanical properties of the samples were tested. The aim is to study the evolution on the microstructure and mechanical properties of the alloy under different processing technologies. After rolling at room temperature, the structure transforms from equiaxed crystals into deformed grains accompanied by twins, and then transforms into static recrystallized grains after the recrystallization treatment. Meanwhile the 18R-LPSO structure shrinks and aggregates. After peak aging treatment, a large number of stacking faults and β′ phases precipitate in some grains. The yield strength (YS) and tensile strength (UTS) of the sheet are enhanced by 24% and 23% compared with those before aging, respectively. After rolling at room temperature, the recrystallized grain size of extruded sheet increases slightly, and 18R-LPSO structure appears irregular bending and delamination. After aging, the YS, UTS and Elongation (EL) of the sheet reach 383 MPa, 420 MPa and 5.5%, respectively.
Key words: Mg-rare earth alloy; long-period stacking ordered (LPSO); rolling; microstructure; mechanical property
