(西北工业大学 航空学院，西安 710072)
摘 要: 利用电子万能实验机对超细晶铜(UFG-Cu)进行温度范围为77~573 K的准静态压缩实验(应变率为1×10−3 s−1)，研究温度对材料流动应力和应变硬化行为的影响。结果表明：与退火粗晶铜相比，超细晶铜在压缩过程中的流动应力显著增大，但是由于材料的位错密度已经饱和，其应变硬化能力却几乎丧失，应变硬化率对应变和温度的依赖性也显著低于退火粗晶铜的；同时，由于晶粒细化导致材料的激活体积减小，超细晶铜的流动应力对温度的敏感性与粗晶铜相比，显著增大。
关键字: 超细晶铜；力学性能；应变硬化；温度敏感性；激活体积
different temperatures
（School of Aeronautics, Northwestern Polytechnical University, Xi’an 710072, China）
Abstract:The quasi-static compression experiments of the annealed coarse-grained copper (CG-Cu) and ultrafine-grained copper (UFG-Cu) were performed at temperatures of 77−573 K and strain rate of 10−3 s−1. The results show that, although UFG-Cu displays extremely high flow stress, the ability of strain hardening almost disappears due to the saturation of dislocation density. The sensitivity of strain hardening rate to strain level and temperature is observed to be lower than those of its coarse counterpart. At the same time, the reduction in activation volume due to the grain refinement is the main reason for the enhanced temperature sensitivity of UFG-Cu.
Key words: ultrafine-grained copper; mechanical behavior; strain hardening; temperature sensitivity; activation volume
