Microstructural Evolution and Anisotropic Weakening Mechanism of ZK60 Magnesium Alloy Processed by Isothermal Repetitive Upsetting Extrusion  

作　　者：Zhengran Liu Xi Zhao Kai Chen Siqi Wang Xianwei Ren Zhimin Zhang Yong Xue 

机构地区：[1]School of Mechanical and Electrical Engineering,North University of China,Taiyuan,030051,China [2]Engineering Technology Research Center for Integrated Precision Forming of Shanxi Province,North University of China,Taiyuan,030051,China

出　　处：《Acta Metallurgica Sinica(English Letters)》2022年第5期839-852,共14页金属学报（英文版）

基　　金：financially supported by the Program for the Supported by Program for the Outstanding Innovative Teams of Higher Learning Institutions of Shanxi;the‘HIGH-GRADE CNC machine tools and basic manufacturing equipment’Major National Science and Technology Projects(No.2019ZX04022001-004)。

摘　　要：The isothermal repetitive upsetting extrusion(RUE)was implemented to process ZK60 magnesium alloy at 380℃.Then,the relationship between the microstructural characters,including grain refinement and texture evolution,and the mechanical performance of the alloy was investigated.Results showed that after 3 passes of RUE,the average grain size was refined from 115.0 to 26.5μm,which was mainly caused by the continuous dynamic recrystallization and discontinuous dynamic recrystallization.Meanwhile,the elongation of the alloy increased from 13.8 to 21.6%,and the superplasticity(142%)of the alloy has been achieved in the following high temperature tensile test,which is very beneficial for the further processing of the alloy into components.In particular,the alloy formed a distinctive texture distributed between<2-1-11>and<2-1-14>,which was greatly related to the Schmid factor of extrusion direction(ED)and transverse direction(TD).This texture changed the initiation ability of basal and prismatic slip in both directions and inhibited the initiation of partial tensile twinning in TD;thus,the anisotropy in both directions was weakened.As expected,the tensile yield strength difference decreased from25.9 to 3.4 MPa,but it was used as the cost of tensile yield strength in ED.

关 键 词：Severe plastic deformation Repetitive upsetting extrusion ZK60 alloy Microstructure Mechanical properties 

分 类 号：TG379[金属学及工艺—金属压力加工]