Mg-8.5Gd-4.5Y-0.8Zn-0.4Zr稀土镁合金室温包套压缩变形行为及变形机制  

Deformation behavior and mechanisms of Mg-8.5Gd-4.5Y-0.8Zn-0.4Zr rare earth magnesium alloy undergoing canning compression at room temperature

作　　者：章懿清 汪丽佳 胡励 何曲波 周涛[1,2] 时来鑫 李明骜 ZHANG Yi-qing;WANG Li-jia;HU Li;HE Qu-bo;ZHOU Tao;SHI Lai-xin;LI Ming-ao(College of Materials Science and Engineering,Chongqing University of Technology,Chongqing 400054,China;Chongqing Key Laboratory of Die Technology,Chongqing University of Technology,Chongqing 400054,China;Chongqing Material Research Institute Co.,Ltd.,Chongqing 400707,China)

机构地区：[1]重庆理工大学材料科学与工程学院,重庆400054 [2]重庆理工大学重庆市模具技术重点实验室,重庆400054 [3]重庆材料研究院有限公司,重庆400707

出　　处：《中国有色金属学报》2023年第7期2125-2136,共12页The Chinese Journal of Nonferrous Metals

基　　金：国家自然科学基金资助项目(51805064);重庆市教育委员会科学技术研究项目(KJQN202101141);中国博士后科学基金资助项目(2021M703592)。

摘　　要：在室温条件下对固溶处理的热挤压态Mg-8.5Gd-4.5Y-0.8Zn-0.4Zr稀土镁合金分别进行单轴压缩与包套压缩实验,采用光学显微(OM)、电子背散射衍射(EBSD)、X射线衍射(XRD)和透射电子显微(TEM)等研究了该合金在变形后的微观组织。合金在单轴压缩条件下的最大变形量为18%,而在包套压缩条件下的最大变形量高达32%。结果表明:该合金在两种变形条件下的微观组织演化规律类似,即均会因协调塑性变形的需要而产生{1012}拉伸孪晶和{1121}拉伸孪晶,且前者的数量多于后者。同时,在变形过程中晶粒c轴向压缩方向的聚集程度逐渐增大。在18%变形量条件下,包套压缩试样的位错密度(0.2728 nm^(−2))明显高于单轴压缩试样的位错密度(0.1796 nm^(−2));在18%变形量条件下的单轴压缩试样中,主要激活的位错类型为〈a〉位错,而〈c+a〉位错数量较少;而在包套压缩试样中,〈c+a〉位错被大量激活来承载塑性应变,进而导致Mg-8.5Gd-4.5Y-0.8Zn-0.4Zr稀土镁合金的室温塑性显著提升。In the present study,the samples of solution-treated Mg-8.5Gd-4.5Y-0.8Zn-0.4Zr rare earth magnesium alloy fabricated by hot extrusion were deformed by uniaxial compression and canning compression at room temperature.The deformed microstructure of this alloy was observed by optical microscopy(OM),electron backscatter diffractometry(EBSD),X-ray diffractometry(XRD)and transmission electron microscopy(TEM).The results show that the maximum deformation degree of this alloy during uniaxial compression is about 18%,while it can reach up to about 32%during canning compression.The microstructure characteristics of this alloy under these two different deformation conditions are similar to each other,namely both{1012}extension twin and{1121}extension twin occur in deformed samples to coordinate plastic defamation.The number of the former is more than that of the latter.Meanwhile,c-axes of grains in this alloy gradually concentrate towards compression direction(CD)with the progression of plastic deformation.The dislocation density(0.2728 nm^(−2))of deformed sample during canning compression is significantly higher than that(0.1796 nm^(−2))of deformed sample during uniaxial compression at same deformation degree of 18%.Within 18%-deformed samples,the dominant slip type is〈a〉slip and only a small amount of〈c+a〉slip is activated during the uniaxial compression.By comparison,〈c+a〉slip has been extensively activated during canning compression to sustain plastic strain.This issue is responsible for the enhanced plasticity of applied Mg-8.5Gd-4.5Y-0.8Zn-0.4Zr rare earth magnesium alloy at room temperature.

关 键 词：稀土镁合金 包套压缩 微观组织演化 变形机制 

分 类 号：TG306[金属学及工艺—金属压力加工]