通过不同热挤压方式制备具有较优强塑性组合的新型Mg-5Sn-2Al-1Zn合金  

Tailoring good combinations between strength and ductility in novel Mg−5Sn−2Al−1Zn alloy via different hot extrusion processes

作　　者：石凤健[1] 朴南瑛 王冀恒[1] 谭昊天 郭宇航[1] 杨飞 陈书锦[1] 芦笙[1] 王泽鑫[1] Feng-jian SHI;Nan-ying PIAO;Ji-heng WANG;Hao-tian TAN;Yu-hang GUO;Fei YANG;Shu-jin CHEN;Sheng LU;Ze-xin WANG(School of Materials Science and Engineering,Jiangsu University of Science and Technology,Zhenjiang 212003,China)

机构地区：[1]江苏科技大学材料科学与工程学院,镇江212003

出　　处：《Transactions of Nonferrous Metals Society of China》2024年第7期2120-2137,共18页中国有色金属学报（英文版）

基　　金：supported by the Jiangsu Province Industry–University–Research Project,China(No.BY20221160);the Postgraduate Research and Practice Innovation Program of Jiangsu Province,China(No.KYCX22_3798);the National Natural Science Foundation of China(No.52275339);the Key Research and Development Plan of the Ministry of Science and Technology,China(No.2023YFE0200400);the Science and Technology Project of Jiangsu Province,China(No.BZ2021053)。

摘　　要：制备新型Mg-5Sn-2Al-1Zn(TAZ521)合金。为提高合金的强度与塑性,采用正挤压(DE)和挤压-剪切(ES)两种工艺对该合金进行变形处理。通过XRD、SEM、TEM、EBSD和拉伸试验等方法研究均匀态和挤压态合金的显微组织演变、织构演变及强化机制。结果表明,正挤压态合金的力学性能得到改善;然而,合金表现出由粗晶和细小动态再结晶(DRXed)晶粒组成的双峰组织。经过挤压-剪切变形后的合金组织变得更加均匀,并且实现更好的强韧性结合,变形后合金的屈服强度(YS)、极限抗拉强度(UTS)和伸长率(EL)分别达到212 MPa、303 MPa和21.7%。晶粒细化和Mg2Sn析出物的钉扎效应对强度的提高起到重要作用,此外,延展性的提高归因于基面纤维织构的弱化和非基面滑移系的激活。A novel Mg−5Sn−2Al−1Zn(TAZ521)alloy was prepared.Direct extrusion(DE)and extrusion−shearing(ES)processes were performed on the alloy to improve its strength and ductility.The microstructure evolution,texture evolution,and strengthening mechanisms of as-homogenized and as-extruded alloy were investigated by XRD,SEM,TEM,EBSD,and tensile tests.The results showed that the mechanical properties of the DE-processed alloy were improved.However,the alloy exhibited a bimodal microstructure consisting of coarse grains and fine DRXed grains.After the ES process,the microstructure became more uniform and a good combination of strength and ductility was achieved.The TYS,UTS,and EL were 212 MPa,303 MPa,and 21.7%,respectively.Grain refinement and pinning effect by Mg2Sn precipitates play an important role in the enhancement of strength.Additionally,the improvement of ductility is attributed to the weak basal fiber texture and the activation of non-basal slip.

关 键 词：Mg-Sn-Al-Zn合金 挤压-剪切 晶粒细化 力学性能 织构演变 

分 类 号：TG376.2[金属学及工艺—金属压力加工] TG146.22[一般工业技术—材料科学与工程]