Mechanical Behavior and Microstructure Evolution of a Rolled Magnesium Alloy AZ31B Under Low Stress Triaxiality  

作　　者：Hongchen Pan Fenghua Wang Li Jin Miaolin Feng Jie Dong 

机构地区：[1]National Engineering Research Center of Light Alloy Net Forming & State Key Laboratory of Metal Matrix Composites,Shanghai Jiao Tong University [2]Department of Engineering Mechanics,Shanghai Jiao Tong University

出　　处：《Journal of Materials Science & Technology》2016年第12期1282-1288,共7页材料科学技术（英文版）

基　　金：financially supported by the National Natural Science Foundation and Bao Steel of China(Grant No.U1360104)

摘　　要：Plastic deformation up to final rupture failure of a rolled magnesium（Mg） alloy Mg-3.0Al-1.0Zn-0.34Mn（AZ31B） under low stress triaxiality was investigated.Local strain evolution was quantified by the digital image correlation（DIC） technique analysis with tensile,combined tensile-shear,and shear specimens,corresponding to the stress triaxiality of 1/3,1/6 and 0,respectively.Stress-strain curves show that the yield stress reduces with the decrease in the stress triaxiality,and obviously exhibits different strain hardening response.Electron backscatter diffraction（EBSD） observations reveal that the twinning behavior depends on stress triaxiality.Before fracture,double twinning is the dominant mechanism at the stress triaxiality of 1/3,while extension twinning is prevalent at the stress triaxiality of 0.Moreover,scanning electron microscopy（SEM） shows that the fracture mechanism is transformed from microvoid growth and coalescence to internal void shearing as the stress triaxiality decreases from 1/3 to 0.Plastic deformation up to final rupture failure of a rolled magnesium（Mg） alloy Mg-3.0Al-1.0Zn-0.34Mn（AZ31B） under low stress triaxiality was investigated.Local strain evolution was quantified by the digital image correlation（DIC） technique analysis with tensile,combined tensile-shear,and shear specimens,corresponding to the stress triaxiality of 1/3,1/6 and 0,respectively.Stress-strain curves show that the yield stress reduces with the decrease in the stress triaxiality,and obviously exhibits different strain hardening response.Electron backscatter diffraction（EBSD） observations reveal that the twinning behavior depends on stress triaxiality.Before fracture,double twinning is the dominant mechanism at the stress triaxiality of 1/3,while extension twinning is prevalent at the stress triaxiality of 0.Moreover,scanning electron microscopy（SEM） shows that the fracture mechanism is transformed from microvoid growth and coalescence to internal void shearing as the stress triaxiality decreases from 1/3 to 0.

关 键 词：Magnesium alloy Stress triaxiality Twinning 

分 类 号：TG146.22[一般工业技术—材料科学与工程] TG301[金属学及工艺—金属材料]