(1. 福州大学 材料科学与工程学院，福州 350108；
2. 福建工程学院 材料科学与工程系，福州 350108)
摘 要: 在应变速率为1.11×10−4~1.67×10−3 s−1、温度为248~523 K的条件下，对固溶态AZ91D变形镁合金进行拉伸试验。结果表明: 在一定的拉伸应变速率和温度区间拉伸时，AZ91D镁合金在形变过程中发生动态应变时效(DSA)现象，其典型特征表现为其拉伸曲线出现锯齿波，所对应的锯齿波类型分别呈A型及A+B混合型；应变速率敏感性系数为负值；且出现加工硬化速率峰值；出现锯齿屈服的临界应变量随变形温度升高而减小，而随应变速率增加而增大；当形变温度大于323 K时，加工硬化速率随着温度升高反而急剧增大，在368 K时达到峰值。
关键字: AZ91D变形镁合金；动态应变时效；锯齿屈服；负应变速率敏感系数；加工硬化速率
AZ91D wrought magnesium alloys
（1. College of Materials Science and Engineering, Fuzhou University，Fuzhou 350108, China;
2. Department of Materials Science and Engineering, Fujian University of Technology, Fuzhou 350108 China）
Abstract:A series of tensile tests of as-solid-solution treated AZ91D wrought magnesium alloys were carried out at strain rates ranging in 1.11×10−4−1.67×10−3 s−1 and temperatures ranging in 248−523 K. The results show that there occurs a dynamic strain aging (DSA) phenomenon during deformation of AZ91D magnesium alloy in certain ranges of temperature and strain rate. The typical characteristics of DSA include serrated flow, the corresponding related serrated types are defined as type A and type A+B. Negative strain-rate sensitivity and peak of work-hardening rate appear. The critical plastic strain for the onset of serrations decreases with increasing deformation temperature, while it increases with increasing strain rate. Moreover, the work-hardening rate increases sharply with increasing temperature when the deformation temperature is higher than 323 K, and reaches the peak value at 368 K.
Key words: AZ91D wrought magnesium alloy; dynamic strain aging; serrated yielding; negative strain-rate sensitivity; work-hardening rate
