温度和应变速率对双辊铸轧、轧制和热处理态AZ31镁合金流动应力行为的影响

摘要

The effects of temperature and strain rate on the flow stress behavior of twin-roll cast, rolled and heat-treated AZ31 magnesium alloys were investigated under uniaxial tension. At high temperatures, dynamic recovery, continuous dynamic recrystallization, grain boundary sliding and the activation of additional slip systems lead to an improvement of the ductility of the alloys. The elongation to failure is nearly independent of the strain rate between 473 and 523 K at 10−2 s−1 and 10−1 s−1, which is related to the strain rate dependence of the critical resolved shear stress (CRSS) for nonbasal slip. Despite the high temperature, twins are even observed at 573 K and 10−3 s−1 because they have a low CRSS.%在单轴拉伸条件下研究温度和应变速率对双辊铸轧、轧制和热处理AZ31镁合金流动应力行为的影响。结果表明，在高温下，动态回复、连续动态再结晶、晶界滑移和附加滑移系的活化使合金的延展得到改善。在473~523 K和10−2~10−1 s−1条件下，合金的断裂伸长率几乎与应变速率无关，而与应变速率依赖于临界剪切应的非基面滑移有关。由于经上述工艺加工的AZ31镁合金具有较低的临界剪切应力，因此在573 K和10−3 s−1条件下出现了孪晶。