扭转及退火工艺对Mg-2Al-1Zn轧板塑性及拉压不对称性的改善(英文)

Enhanced ductility and reduced asymmetry of Mg-2Al-1Zn alloy plate processed by torsion and annealing

采用光学显微镜及电子背散射技术(EBSD)等手段研究扭转及后续退火工艺对热轧板Mg-2Al-1Zn镁合金塑性及拉压不对称性的改善。室温扭转后,样品的屈服强度、抗压强度以及压缩塑性都得到同步提高;随着扭转应变量的增加,样品的压缩塑性提高;并且在退火后,扭转试样的塑性得到大幅度提升,断裂时的最大真应变为0.279,是原始轧制态的2倍。此外,扭转及扭转/退火后的样品拉压不对称性得到明显改善。分析表明,镁合金样品塑性的大幅度提高及拉压不对称性的改善主要是由于在扭转及后续退火过程中生成晶粒得到细化的梯度组织,以及原始强基面板织构的弱化和随机化。

The ductility and plastic asymmetry of an as-annealed magnesium alloy plate were studied in compression through combined process of torsion and subsequent annealing by optical microscope and EBSD. The yield strength（YS） and ultimate compression strength（UCS） as well as the compression ductility（CD） were simultaneously raised by prior torsion at room temperature. The CD was further enhanced by subsequent annealing. Also, the torqued sample followed by annealing experienced a rising CD with the increase in prior strain, leading to the maximum true strain of 0.279, which is twice that of the as-annealed original one. The sample showed a largely reduced tension-compression yield asymmetry by subjecting to pre-torsion alone or combined with a subsequent annealing. The enhanced ductility and reduced asymmetry are attributed to the development of a gradient microstructure with refined grains, and also randomization of the weakened texture due to torsion and subsequent annealing.