热挤压和锻造制备高延性和高吸能超细晶粒Mg-Mn-Ce合金  

Preparation of ultrafine-grained Mg-Mn-Ce alloy with high ductility and energy absorption by coupling extrusion and forging

作　　者：张宇修 张至柔[1] 王春雨 康宏辉 Hiromi NAGAUMI 杨续跃[1] Yu-xiu ZHANG;Zhi-rou ZHANG;Chun-yu WANG;Hong-hui KANG;Hiromi NAGAUMI;Xu-yue YANG(School of Materials Science and Engineering,Central South University,Changsha 410083,China;School of Iron and Steel,Soochow University,Suzhou 215100,China)

机构地区：[1]中南大学材料科学与工程学院,长沙410083 [2]苏州大学沙钢钢铁学院,苏州215100

出　　处：《Transactions of Nonferrous Metals Society of China》2023年第12期3661-3672,共12页中国有色金属学报（英文版）

基　　金：the financial support from the National Key Research and Development Program of China(No.2022YFE0109600,2021YFB3701100);the National Natural Science Foundation of China(No.52071344,52150710544)。

摘　　要：采用挤压和锻造低温变形方法制备高压缩延性和高吸能性超细晶粒Mg-0.9Mn-0.5Ce(质量分数,%)合金。首先将合金在温度为150℃、挤压比为12:1的条件下进行挤压;随后,在200℃下沿挤压方向进行真应变为1.2的锻造处理。采用光学显微镜、扫描电镜、电子背散射衍射和透射电镜对合金的显微组织和塑性机理进行表征。结果表明,经低温挤压后合金组织由超细的动态再结晶晶粒和破碎的未再结晶晶粒组成,其平均晶粒尺寸为1.9μm。在随后的锻造过程中,逐渐产生新的超细晶粒,获得均匀的超细晶粒组织,其平均晶粒尺寸为2.7μm,织构强度也在锻造处理后减弱。均匀的超细晶粒组织和基面滑移使合金表现出较优的综合性能:压缩延性为45.0%,吸能为122.72 MJ/m^(3)。An ultrafine-grained(UFGed)Mg-0.9Mn-0.5Ce(wt.%)alloy with high compressive ductility and energy absorption was developed using a low-temperature deformation method of coupling extrusion and forging.Specifically,the alloy was extruded at 150℃ with an extrusion ratio of 12:1,followed by forging at 200℃ to a true strain of 1.2 along the extrusion direction.The microstructure and plastic mechanism were uncovered using optical microscopy,scanning electron microscopy,electron backscatter diffraction and transmission electron microscopy.The microstructure was found to consist of ultrafine dynamically recrystallized(DRXed)grains and fragmented unDRXed grains,exhibiting an average grain size of 1.9μm after low-temperature extrusion.After forging,new UFGs were gradually generated,a uniform UFGed microstructure with an average grain size of 2.7μm was obtained,and the texture intensity was decreased as well.The homogenous UFGs and basal slip collaboratively contributed to better comprehensive performance of the UFGed alloy,such as a high compressive ductility of 45.0% and a high energy absorption of 122.72 MJ/m^(3).

关 键 词：Mg-Mn-Ce合金 超细晶 延性 吸能 

分 类 号：TG146.22[一般工业技术—材料科学与工程] TG319[金属学及工艺—金属材料] TG379[金属学及工艺—金属学]