Effect of Gd Addition on Hot Deformation Behavior and Microstructure Evolution of 7075 Aluminum Alloy  

作　　者：LI Yajie FAN Xuran QIN Fengming ZHAO Xiaodong CAO Kefan 李亚杰;赵晓东

机构地区：[1]School of Materials Science and Engineering,Taiyuan University of Science and Technology,Taiyuan 030024,China

出　　处：《Journal of Wuhan University of Technology(Materials Science)》2024年第6期1595-1612,共18页武汉理工大学学报（材料科学英文版）

基　　金：Funded by the Fundamental Research Program of Shanxi Province(Nos.202103021224282 and 202103021223288);the Central Government Guides Local Funds for Science and Technology Development(Nos.YDZJSX20231A045 and YDZJSX2024D053)。

摘　　要：In order to clarify the effect of rare earth Gd on the microstructure evolution and deformation behavior of 7075 aluminum alloy during hot compression,uniaxial compression tests of Al-Zn-Mg-Cu-0.5%Gd were conducted at strain rates of 0.001,0.01,0.1,and 1 s^(-1)with the temperatures ranging from 350 to 450℃.The microstructural evolution during deformation was characterized using optical microscopy and electron backscatter diffraction(EBSD)techniques.The experimental results indicate that the addition of the rare earth element Gd significantly increases the peak flow stress and thermal activation energy of the alloy.Due to the pinning effect of rare earth phases,dislocation movement is hindered,leading to an increased level of work hardening in the alloy.However,the dynamic recrystallization of the alloy is complicated.At a high Z(Zener-Hollomon parameter)values,recrystallization occurs in the form of DDRX(Discontinuous Dynamic Recrystallization),making it easier to nucleate at grain boundaries.As the Z value decreases gradually,the recrystallization mechanism transitions from discontinuous dynamic recrystallization(DDRX)to continuous dynamic recrystallization(CDRX).At a low Z values with the strain rate of 0.001 s^(-1),the inhibitory effect of rare earths weakens,resulting in a comparable recrystallization ratio between Al-Zn-Mg-Cu-Gd alloy and 7075 aluminum alloy.Moreover,the average grain size of the aluminum alloy with Gd addition is only half that of 7075 aluminum.The addition of Gd provides Orowan and substructure strengthening for the alloy,which greatly improves the work-hardening of the alloy compared with 7075 aluminum alloy and improves the strength of the alloy.

关 键 词：Al-Zn-Mg-Cu-Gd hot deformation behavior constitutive model dynamic recrystallization microstructure evolution 

分 类 号：TG146.21[一般工业技术—材料科学与工程]