(西北工業(yè)大學(xué) 航空學(xué)院，西安 710072)
摘 要: 利用電子萬(wàn)能實(shí)驗(yàn)機(jī)對(duì)超細(xì)晶銅(UFG-Cu)進(jìn)行溫度范圍為77~573 K的準(zhǔn)靜態(tài)壓縮實(shí)驗(yàn)(應(yīng)變率為1×10−3 s−1)，研究溫度對(duì)材料流動(dòng)應(yīng)力和應(yīng)變硬化行為的影響。結(jié)果表明：與退火粗晶銅相比，超細(xì)晶銅在壓縮過(guò)程中的流動(dòng)應(yīng)力顯著增大，但是由于材料的位錯(cuò)密度已經(jīng)飽和，其應(yīng)變硬化能力卻幾乎喪失，應(yīng)變硬化率對(duì)應(yīng)變和溫度的依賴性也顯著低于退火粗晶銅的；同時(shí)，由于晶粒細(xì)化導(dǎo)致材料的激活體積減小，超細(xì)晶銅的流動(dòng)應(yīng)力對(duì)溫度的敏感性與粗晶銅相比，顯著增大。
關(guān)鍵字: 超細(xì)晶銅；力學(xué)性能；應(yīng)變硬化；溫度敏感性；激活體積
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
