室温ECAP加冷轧制备镍超细晶退火后的组织性能研究  

Study on Microstructure and Properties of Ni Ultrafine Grain Prepared by Room Temperature ECAP and Cold Rolling After Annealing

作　　者：牛帅隆 刘帆[1] 王经涛[1] 

机构地区：[1]南京理工大学材料科学与工程学院,江苏南京210094

出　　处：《热加工工艺》2017年第1期44-48,共5页Hot Working Technology

基　　金：教育部科学技术研究重大项目(311035)

摘　　要：室温下采用等径弯曲通道变形(Equal Channel Angular Pressing,ECAP)Bc路径对纯镍(99.99%)进行8道次挤压变形,然后对其进行压下量为75%的冷轧变形。通过不同的退火试验,研究了ECAP加冷轧变形后退火纯镍的显微硬度和显微组织变化。结果表明:在退火期间组织表现为不连续静态再结晶。当退火温度低于280℃时,试样的显微硬度下降缓慢,组织变化不大;当退火温度高于280℃时,显微硬度迅速下降,组织发生再结晶。再结晶动力学分析表明:当退火温度低于300℃时,样品在退火过程中发生二维生长;当退火温度高于320℃时,发生三维生长。样品再结晶表观激活能经估算约为(77±4)k J/mol,与晶界扩散能几乎保持一致。The eight passes extrusion deformation of pure nickel （99.99%） was carried out by using equal channel angular pressing （ECAP） with Bc route at room temperature. And then the cold-rolling deformation at the reduction of 75% was carried out. The micro-hardness and microstructure changes of annealed pure nickel after ECAP and cold rolling deformation were studied by different annealing experiments. The results show that the microstructure is discontinuous static recrystallization during annealing. When the annealing temperature is below 280 ℃, the micro-hardness of samples slightly decreases, and its microstructure changes little. When the annealing temperature is over 280 ℃, the micro-hardness decreases rapidly, and the recrystallization occurs in microstructure. Analysis of recrystallization kinetics show that when the annealing temperature is lower than 300℃, two dimensional growth occurs during the annealing process. When the annealing temperature is higher than 320℃, three dimensional growth occurs. The apparent activation energy of the samples is approximately （77±4） kJ/mol by estimate,which is consistent with the grain boundary diffusion energy.

关 键 词：等径角挤压 冷轧 退火 热稳定性 再结晶动力学 

分 类 号：TG146.1[一般工业技术—材料科学与工程] TG156.2[金属学及工艺—金属材料]