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ZK40镁合金高应变速率高温压缩变形行为和组织演变

发表时间:2010-10-31  浏览量:1769  下载量:940
全部作者: 吴远志,严红革,陈吉华,朱素琴,刘志文,田津
作者单位: 湖南大学材料科学与工程学院
摘 要: 研究ZK40镁合金高温压缩变形行为和组织演变,并通过建立本构方程,得到ZK40镁合金热变形激活能和应力指数。结果表明:ZK40合金热变形激活能Q和应力指数n分别为149.5 kJ/mol,8.36;低应变速率下(≤1 s-1)动态再结晶(dynamic recrystallization, DRX)主要在晶界上发生,高应变速率下(≥10 s-1)在晶界和孪晶上都产生大量的再结晶晶粒,得到比低应变速率更均匀的变形组织,在高应变速率条件下合金热加工成形性能好;应变速率为20 s-1和50 s-1时,随着温度的升高再结晶晶粒出现异常长大,而应变速率为10 s-1时,再结晶晶粒度在所有的温度范围内保持一致;ZK40合金最佳热加工工艺参数为250~400℃ 和10 s-1.
关 键 词: 合金材料;镁合金;动态再结晶;热压缩;显微组织
Title: Hot deformation behavior and microstructure evolution of ZK40 magnesium alloy compressed at high strain rates
Author: WU Yuanzhi, YAN Hongge, CHEN Jihua, ZHU Suqin, LIU Zhiwen, TIAN Jin
Organization: College of Materials Science and Engineering, Hunan University
Abstract: The hot compression deformation behavior and microstructure evolution of the homogenized ZK40 magnesium alloy were investigated. The activation energy Q and stress exponent n deduced to be 149.5 kJ/mol and 8.36 by carrying out constitutive analysis. At the lower strain rate (≤1 s-1), dynamic recrystallization (DRX) developed mainly at the grain boundaries. At the higher strain rate (≥10 s-1), DRX developed extensively at the grain boundaries and twins, resulting in a more homogeneous microstructure than the other conditions. The hot deformation characteristics of ZK40 exhibited an abnormal relationship with the strain rate, namely the hot workability increased with the strain rate increasing. However, the DRX grain size was almost the same with the temperature increasing at the strain rate of 10 s-1, while that increased obviously at the strain rate of 20 s-1 and 50 s-1. Therefore, hot deformation at the strain rate of 10 s-1 around and at the temperature range of 250-400℃ was desirable and feasible for the ZK40.
Key words: alloy material; magnesium alloy; dynamic recrystallization; hot compression; microstructure
发表期数: 2010年10月第20期
引用格式: 吴远志,严红革,陈吉华,等. ZK40镁合金高应变速率高温压缩变形行为和组织演变[J]. 中国科技论文在线精品论文,2010,3(20):2097-2014.
 
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