Strain-hardening and warm deformation behaviors of extruded Mg-Sn-Yb alloy sheet  

作　　者：Jing Jiang Guangli Bi Guoyong Wang Qing Jiang Jianshe Lian Zhonghao Jiang 

机构地区：[1]Key Laboratory of Automobile Materials,College of Materials Science and Engineering,Jilin University,Nanling Campus,Changchun 130025,China [2]State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals,Lanzhou University of Technology,Lanzhou 730050,China

出　　处：《Journal of Magnesium and Alloys》2014年第2期116-123,共8页镁合金学报（英文）

基　　金：This work was financially supported by the National Nature Science Foundations of China(No.51371089 and No.51301082).

摘　　要：Strain-hardening and warm deformation behaviors of extruded Mg-2Sn-0.5Yb alloy(at.%)sheet were investigated in uniaxial tensile test at temperatures of 25-250 ℃ and strain rates of 1×10^(−3) s^(−1)-0.1 s^(−1).The data fit with the Kocks-Mecking type plots were used to show different stages of strain hardening.Besides III-stage and IV-stage,the absence of the II-stage strain hardening at room temperature should be related to the sufficient dynamic recrystallization during extrusion.The decrease of strain hardening ability of the alloy after yielding was attributed to the reduction of dislocation density with increasing testing temperature.Strain rate sensitivity(SRS)was significantly enhanced with increasing temperature,and the corresponding m-value was calculated as 0.07-0.12,which indicated that the deformation mechanism was dominated by the climb-controlled dislocation creep at 200 ℃.Furthermore,the grain boundary sliding(GBS)was activated at 250 ℃,which contributed to the higher SRS.The activation energy was calculated as 213.67 kJ mol^(−1),which was higher than that of lattice diffusion or grain boundary self-diffusion.In addition,the alloy exhibited a quasi superplasticity at 250 ℃ with a strain rate of 1×10^(−3) s^(−1),which was mainly related to the fine microstructure and the presence of the Mg2Sn and Mg2(Sn,Yb)particles.

关 键 词：Mg-Sn-Yb alloy sheet Strain hardening Strain rate sensitivity Activation energy 

分 类 号：TG1[金属学及工艺—金属学]