挤压AM80-(0.2Sr)镁合金准静态载荷拉-压变形力学响应行为及其不对称性研究  

Study on mechanical response behavior and asymmetry of tensioncompression deformation of extruded AM80-(0.2Sr)magnesium alloys under quasi-static load

作　　者：肖罡 郭鹏程[1,3,4] 王文韫 项忠珂[1] 杨钦文 XIAO Gang;GUO Peng-cheng;WANG Wen-yun;XIANG Zhong-ke;YANG Qin-wen(School of Artificial Intelligence,Jiangxi University of Science and Technology,Nanchang 330098,China;Jiangxi Copper Technology Research Institute Co.,Ltd.,Nanchang 330096,China;School of Mechanical and Vehicle Engineering,Hunan University,Changsha 410082,China;School of Mechanical and Electrical Engineering,Central South University of Forestry and Technology,Changsha 410004,China)

机构地区：[1]江西科技学院人工智能学院,江西南昌330098 [2]江西铜业技术研究院有限公司,江西南昌330096 [3]湖南大学机械与运载工程学院,湖南长沙410082 [4]中南林业科技大学机电工程学院,湖南长沙410004

出　　处：《塑性工程学报》2024年第6期149-157,共9页Journal of Plasticity Engineering

基　　金：国家自然科学基金资助项目(52075159);江西省自然科学基金资助项目(20224ACB218002);湖南省自然科学基金资助项目(2022JJ30019);江西省高层次高技能领军人才培养工程资助项目;长沙市科技计划项目(kq2208420);广西大学省部共建特色金属材料与组合结构全寿命安全国家重点实验室开放基金资助项目(2022GXYSOF24)

摘　　要：通过室温条件下的准静态拉伸和压缩试验,研究了挤压AM80-(0.2Sr)镁合金拉伸和压缩变形的力学响应行为及不对称性,并探讨了Sr元素对力学响应行为的影响。结果表明:挤压AM80和AM80-0.2Sr镁合金均具有显著的拉-压变形不对称性。挤压AM80和AM80-0.2Sr的拉伸与压缩的屈服强度比b分别为2.06和2.28,拉伸与压缩的极限强度比c分别为0.78和0.81,且拉伸应变硬化率大幅低于压缩变形。此外,在拉伸变形过程中,两镁合金试样均出现了明显的动态应变时效,其锯齿波动由C型逐渐演变为B型。相较于压缩变形,两种镁合金试样在拉伸变形过程中的动态应变时效更明显。适量添加Sr元素有利于提升拉伸的屈服强度和极限强度,但会降低断裂应变以及压缩的屈服强度和极限强度,并抑制拉伸变形过程中的动态应变时效。两种镁合金的断裂失效机制均为微裂纹的形核和穿晶扩展,微裂纹优先在变形较为严重且出现孪晶交叉的晶界处形核,然后沿与拉伸载荷夹角约为45°的方向扩展,直至贯穿多个晶粒。The mechanical response behavior and asymmetry of extruded AM80-(0.2Sr)magnesium alloys were studied by quasi-static tension-compression tests at room temperature,and the influence of Sr element on the mechanical response behavior was discussed.The results show that the extruded AM80 and AM80-0.2Sr alloys exhibit significant asymmetry in tension-compression.For the extruded AM80 and AM80-0.2Sr alloys,the yield strength ratios of tension and compression b are 2.06 and 2.28,and the ultimate strength ratios of tension and compression c are 0.78 and 0.81,respectively.And the strain hardening rate of tension is much lower than that of compression.Additionally,the two magnesium alloys show obvious dynamic strain aging during tension deformation,and their serrations gradually e-volve from C-type to B-type.Compared with the compression deformation,the dynamic strain aging of two megnesium alloy during tension deformation is more obvious.Appropriate addition of Sr element can improve the yield strength and ultimate strength of tension,but reduce the fracture strain and compression yield strength and ultimate strength.In addition,it also inhibits the dynamic strain aging during tension deformation.The fracture failure mechanism of the two magnesium alloys is nucleation and transgranular propagation of microcracks.The microcracks nucleate preferentially at grain boundaries where the deformation is more severe and twin intersections occur,and then propagate along the direction with an angle of about 45°to the tensile load until they penetrate through multiple grains.

关 键 词：AM80镁合金 准静态拉压 力学响应 不对称性 

分 类 号：TG146.4[一般工业技术—材料科学与工程]