中文摘要：

塑料变丑直到卷的镁(Mg ) 的最后的破裂失败在低压力 triaxiality 下面的合金 Mg-3.0Al-1.0Zn-0.34Mn (AZ31B ) 被调查。本地紧张进化被数字图象关联(DIC ) 确定有张力的、联合张力砍的技术分析，并且砍标本，相应于 1/3 的压力 triaxiality， 1/6 并且 0 分别地。压力紧张弄弯收益压力在压力 triaxiality 与减少减少的表演，并且显然展出不同紧张变硬反应。电子反散射衍射(EBSD ) 观察表明 twinning 行为取决于压力 triaxiality。在骨折前，两倍 twinning 是在 1/3 的压力 triaxiality 的主导的机制，当延期 twinning 在 0 的压力 triaxiality 是流行的时。而且，扫描电子显微镜学(SEM ) 证明破裂机制从微虚空的生长和结合被转变到当压力 triaxiality 从 1/3 减少到 0，砍的内部虚空。

英文摘要：

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.