The effect of temperature on mechanical behavior of ultrafine-grained copper by equal channel angular pressing
The effect of temperature on mechanical behavior of ultrafine-grained copper by equal channel angular pressing
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DOI：
10.1016/j.msea.2010.05.046
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发表时间：
2010-08
期刊：
影响因子：
6.4
通讯作者：
T. Suo;Yulong Li;K. Xie;F. Zhao;Ke-shi Zhang;Yuan-yong Liu
中科院分区：
文献类型：
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作者：
T. Suo;Yulong Li;K. Xie;F. Zhao;Ke-shi Zhang;Yuan-yong Liu
采用等通道转角挤压法制备了退火后的粗晶铜（Cu 99.9）和超细晶铜，在77 ~ 573 K温度范围内进行了准静态压缩实验。在实验的基础上，研究了温度对流变应力、应变硬化率的影响。结果表明，超细晶铜的流变应力对试验温度的敏感性远大于粗晶铜。然而，超细晶铜对真应变的温度敏感性比粗晶铜弱。此外，超细晶铜的应变硬化速率和温度敏感性均低于粗晶铜。基于热激活理论，提出超细晶铜的温度敏感性增强可能与晶粒细化导致激活体积减小有关。
Quasi-static compression experiments of annealed coarse grained copper (Cu 99.9) and ultrafine-grained copper fabricated by equal channel angular pressing method were performed at temperatures ranging from 77 to 573K. Based on experimental results, the influence of temperature on flow stress, strain hardening rate is investigated carefully. The results show that the flow stress of ultrafine-grained copper displays much larger sensitivity to testing temperature than that of coarse grained copper. However, the temperature sensitivity of ultrafine-grained copper to true strain is comparatively weaker than that of coarse grained copper. Moreover, for the ultrafine-grained copper, both the strain hardening rate and its sensitivity to temperature are lower than those of its coarse counterpart. Based on thermal activation theory, it is proposed that the enhanced temperature sensitivity of ultrafine-grained copper can be related to the reduction in activation volume due to grain refinement.