(1. 福州大學 材料科學與工程學院，福州 350108；
2. 福建工程學院 材料科學與工程系，福州 350108)
摘 要: 在應變速率為1.11×10−4~1.67×10−3 s−1、溫度為248~523 K的條件下，對固溶態(tài)AZ91D變形鎂合金進行拉伸試驗。結果表明: 在一定的拉伸應變速率和溫度區(qū)間拉伸時，AZ91D鎂合金在形變過程中發(fā)生動態(tài)應變時效(DSA)現(xiàn)象，其典型特征表現(xiàn)為其拉伸曲線出現(xiàn)鋸齒波，所對應的鋸齒波類型分別呈A型及A+B混合型；應變速率敏感性系數(shù)為負值；且出現(xiàn)加工硬化速率峰值；出現(xiàn)鋸齒屈服的臨界應變量隨變形溫度升高而減小，而隨應變速率增加而增大；當形變溫度大于323 K時，加工硬化速率隨著溫度升高反而急劇增大，在368 K時達到峰值。
關鍵字: AZ91D變形鎂合金；動態(tài)應變時效；鋸齒屈服；負應變速率敏感系數(shù)；加工硬化速率
AZ91D wrought magnesium alloys
（1. College of Materials Science and Engineering, Fuzhou University，F(xiàn)uzhou 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
