Xiao Hongchao, Yang Zhengjiang, Li Jie, Wan Yingchun
School of Metallurgy and Environment, Central South University, Changsha 410083, China.
School of Materials Science and Engineering, Central South University, Changsha 410083, China.
Materials (Basel). 2021 Jun 12;14(12):3262. doi: 10.3390/ma14123262.
When Mg-Gd-Y-Zr alloy is cold forged, a large number of nano-micro shear bands are formed inside the grains. It is observed that micro-shear bands hinder the sliding of dislocations, resulting in an increase in tensile strength at elevated temperatures. The subsequent aging treatment further strengthens the alloy. Compared with unforged aged alloys, aged samples with pre-generated micro-shear bands exhibit higher strength at room temperature to 250 °C, but exhibit similar properties at higher temperatures. Microstructure characterization and fracture behavior analysis indicate that the transformation of deformation mode from dislocation sliding to grain boundary activity is mainly due to the change of mechanical properties with temperature. In addition, the alloy precipitates with the aid of dislocations during tension, and exhibits higher strength at 200 °C than that at room temperature.
当Mg-Gd-Y-Zr合金进行冷锻时，晶粒内部会形成大量纳米-微米级的剪切带。据观察，微剪切带会阻碍位错的滑动，从而导致高温下抗拉强度的增加。随后的时效处理进一步强化了该合金。与未锻造的时效合金相比，具有预先生成微剪切带的时效样品在室温至250°C范围内表现出更高的强度，但在更高温度下表现出相似的性能。微观结构表征和断裂行为分析表明，变形模式从位错滑动向晶界活动的转变主要是由于力学性能随温度的变化。此外，该合金在拉伸过程中借助位错析出，并且在200°C时比室温下表现出更高的强度。
