基于等径通道挤压法的超细晶铜动态剪切变形行为实验研究  

Experimental Research on Dynamic Shear Behavior of Ultrafine-grained Copper Prepared by Equal Channel Angular Pressing

作　　者：宋鹏飞 董新龙[1] 付应乾[1,2] 索涛[3] SONG Peng-fei1 , DONG Xin-long1 , FU Ying-qian1,2 , SUO Tao3(1. Faculty of Mechanical Engineering and Mechanics, Ningbo University, Ningbo 315211, Zhejiang, China; 2. Sehool of Meehatronieal Engineering, Beijing Institute of Teehnology, Beijing 100081, China; 3. School of Aeronautics, Northwestern Polyteehnieal University, Xi＇an 710072, Shaanxi, Chin)

机构地区：[1]宁波大学机械工程与力学学院,浙江宁波315211 [2]北京理工大学机电学院,北京100081 [3]西北工业大学航空学院,陕西西安710072

出　　处：《兵工学报》2018年第4期763-771,共9页Acta Armamentarii

基　　金：国家自然科学基金项目(U1230122;11672143)

摘　　要：采用等径通道挤压(ECAP)法制备了超细晶铜,分析其微结构的热稳定性及其对材料动态力学性能的影响。利用Hopkinson压杆及MTS液压伺服实验机对ECAP超细晶铜和原始铜帽型剪切试样进行应变控制加载,结合图像数字相关法及"冻结"回收试样的微观和X射线衍射分析,对其动态剪切变形行为及微观组织演化开展研究。结果表明:ECAP后的超细晶铜在准静态剪切下具有应变硬化特征,但在高应变率下剪切应力-剪切应变曲线呈软化特征;高加载率下产生动态再结晶的绝热剪切带是导致应变硬化率为负的原因;按塑性功计算的超细晶铜再结晶温度仅为325 K,因此超细晶铜在高应变率下易发生绝热剪切失稳变形现象。The thermal stability of ultra-fine-grained（ UFG） copper microstructure prepared by equal channel angular pressing（ ECAP） method and its influence on the mechanical properties of the material are studied. The Hopkinson pressure bar and MTS hydraulic servo testing machine are used to test ECAP ultrafine grained copper and annealed pure copper samples under strain controlled loading. The evolutions of its dynamic shear deformation behavior and microstructure are studied by digital image correlation method and the microscopic and XRD analysis of ＂frozen＂recovered samples. The test shows that the ECAP UFG copper has strain hardening characteristics under quasi-static shear loading; the shear stressstrain curve presents strain softening characteristics at high strain rate; and the adiabatic shear dynamic recrystallization zone results in strain hardening rate being negative at high loading rate. The recrystalliza-tion temperature of ultrafine grained copper calculated by plastic work is only 325 K. Therefore,the adiabatic shear instability of ultrafine grained copper at high strain rate is easy to occur.

关 键 词：超细晶铜 等径通道挤压法 动态剪切 应变软化 动态再结晶 绝热剪切 

分 类 号：TG113.253[金属学及工艺—物理冶金]