Deformation mechanisms and microstructural characteristics of AZ61 magnesium alloys processed by a continuous expansion extrusion approach  

作　　者：Yang Mo Fulin Jiang Hang Xu Jie Tang Dingfa Fu Hui Zhang Jie Teng 

机构地区：[1]College of Materials Science and Engineering,Hunan University,Changsha 410082,China

出　　处：《Journal of Magnesium and Alloys》2024年第7期2826-2846,共21页镁合金学报（英文）

基　　金：supported by the National Natural Science Foundation of China(52074114,52174361);Graduate Training and Innovation Practice Base of Hunan Province.

摘　　要：The unique continuous extrusion-based severe plastic deformation approaches were proposed recently to process high-performance magnesium (Mg) alloys,while the in-depth deformation mechanisms under such complicated thermomechanical conditions were not well understood In the present work,the fundamental deformation behaviors of AZ61 Mg alloy from 25 to 400°C were firstly examined under uniaxial compression deformation.Then the deformation mechanisms and microstructural characteristics of AZ61 Mg alloy during continuous expansion extrusion forming (CEEF) were systematically investigated by microstructural observations,finite element and cellular automata simulations The results showed that the continuous evolutions of temperature,larger strain level and complex stress state with strain rate range of 0~5.98 s-1during CEEF brought the distinctive dynamic recrystallization behaviors and texture development in AZ61 Mg alloy,which were different to that of uniaxial compression deformation.In details,a remarkable grain refinement was achieved via CEEF processing due to the simultaneous actions of continuous dynamic recrystallization (CDRX) and discontinuous dynamic recrystallization (DDRX).Gradually enhanced CDRX were observed from center to edge region,which had significant effects on the texture distribution and texture strength.The c-axis of most grains rotated under distinctive shear strain following parabolic metal flow,resulting in stable fiber texture.In addition,the evolution of the internal texture of the alloy led to an obvious increase in the Schmid factor for the activation of basal(c+a)slip system.©2022 Chongqing University.Publishing services provided by Elsevier B.V.on behalf of Ke Ai Communications Co.Ltd.

关 键 词：Magnesium alloy Deformation Continuous expansion extrusion forming Microstructure Finite element simulation 

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