纳米金属镍的冷轧变形与微结构

Deformation mechanism and microstructure evolution of nanocrystalline nickel processed by cold rolling

在室温条件下对纳米金属镍进行了不同程度的冷轧变形,利用X射线衍射分析和高分辨透射电镜的观察对纳米金属镍的微观结构演变以及塑性变形机制进行了研究。结果表明:形变量ε<20%时,晶粒旋转为主要的变形方式;当20%<ε<30%时,位错活动与晶粒旋转共同协调变形;ε>30%时,晶界发射的不全位错,形成变形孪晶与层错,主导变形。

Nanocrystalline nickel was cold-rolled with different strain at room temperature.Microstructure evolution and plastic deformation mechanism of nanocrystalline nickel were examined by means of high-resolution transmission electronic microscope（HRTEM） and X-ray diffraction （XRD）. The results show that when the strain ε〈20%, deformation is dominated by grain rotation. When 20%〈ε〈30%, full dislocation slip and grain rotation realizes the deformation. When ε〉30%, partial dislocation generated from GBs leads to twinning and stacking faults, dominating the deformation.