低温等通道转角挤压中定向凝固纯铜的组织及性能演变  

The Evolution of Microstructure and Properties of Directional Solidification Pure Copper During Equal Channel Angular Pressing at Low Temperature

作　　者：郭廷彪[1,2] 李琦[1] 王晨[1] 张锋[1] 丁雨田[1,2] 贾智[1,2] 唐兴昌 GUO Tingbiao;LI Qi;WANG Chen;ZHANG Feng;DING Yutian;JIA Zhi;TANG Xingchang(State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals, Lanzhou University of Technology,Lanzhou 730050;Key Laboratory of Non-ferrous Metal Alloys and Processing of Ministry of Education,Lanzhou University of Technology, Lanzhou 730050)

机构地区：[1]兰州理工大学省部共建有色金属先进加工与再利用国家重点实验室,兰州730050 [2]兰州理工大学有色金属合金及加工教育部重点实验室,兰州730050

出　　处：《材料导报》2018年第10期1650-1654,1687,共6页Materials Reports

基　　金：国家自然科学基金(51261016)

摘　　要：采用光学显微镜(OM)和XRD技术对干冰冷却后的定向凝固纯铜(99.99%)经等通道转角挤压(ECAP)时的微观组织演变规律进行研究,并测试了ECAP后定向凝固纯铜的硬度及导电性能。结果表明,定向凝固纯铜在低温下经A和C路径变形后易于形成取向一致的纤维组织,并且保持(111)面的择优取向特征,而经Bc路径变形后,柱状晶破碎,形成均匀的等轴晶,且各晶面逐渐趋于随机取向;经过1道次变形后,各路径硬度大幅增加,约为原来的1.8倍,在随后的挤压中,硬度增加缓慢,经4道次ECAP后,Bc路径的硬度有所下降;在低应变下,晶粒取向的一致性使得导电率增加;随着应变的增加,晶格畸变使得电子发生散射,使导电率略有降低。The microstructure evolution of directional solidification structure in pure copper（99.99%）during equal channel angular pressing（ECAP）after cooling with dry ice was investigated by OM and XRD,the hardness and conductivity were tested.The results manifested that the fibrous structure with same orientation was formed in directional solidification structure in pure copper by route A and C at low temperature,and the characterization of（111）preferred orientation was remained.After deformation by route Bc,columnar crystal of directional solidification structure in pure copper was broken,and homogeneous equiaxed grains were formed,at the same time,the grain orientation tended to be random.The hardness of each route increased drastically after one pass extrusion,which was about 1.8 times in compare with hardness of original sample,with the increase of extrusion passes,the hardness increased slowly,whereas the hardness decreased slightly after four passes extrusion by route Bc.The consistency of grain orientation made the conductivity increased in the condition of low strain,however,with the increase of strain,lattice distortion caused electron scattering,which leaded to a slight decrease in conductivity.

关 键 词：定向凝固纯铜 等通道转角挤压(ECAP) 晶粒取向 微观组织 导电率 

分 类 号：TG379[金属学及工艺—金属压力加工]