( 1. 廣西大學(xué) 物理科學(xué)與工程技術(shù)學(xué)院，南寧 530004；
2. 西南交通大學(xué) 材料科學(xué)與工程學(xué)院, 成都 610031；
3. 中國科學(xué)院力學(xué)所 非線性力學(xué)國家實驗室， 北京 100080；
4. 重慶大學(xué) 材料科學(xué)與工程學(xué)院， 重慶 300044)
摘 要: 利用透射電鏡對冷軋變形所致納米結(jié)構(gòu)金屬鎳的微結(jié)構(gòu)組織演變特征進行了研究。 結(jié)果表明， 經(jīng)過軋制變形后， 納米晶的平均晶粒尺寸為50~70 mm，有少量位錯結(jié)構(gòu)， 但沒有發(fā)現(xiàn)位錯堆積纏結(jié)； 在晶界處及附近有臺階界面結(jié)構(gòu)， 以及與臺階形狀相對應(yīng)的應(yīng)力場襯度。 在變形后期， 可以靠晶界發(fā)射不全位錯從而促使層錯生成，并依賴層錯尺寸長大（即層錯界面位錯）的運動進行。 而當層錯尺寸長大時， 其前沿局部變形應(yīng)力逐漸變大， 直至該應(yīng)力大到一定值時， 位錯停止運動， 層錯尺寸也不再長大，并留下了臺階結(jié)構(gòu)。
關(guān)鍵字: 納米晶體； 微觀結(jié)構(gòu)； 塑性變形； 層錯； 位錯
ZHOU Ming-zhe1
（ 1. School of Physical Science and Engineering Technology,
Guangxi University, Nanning 530004, China;
2. School of Materials Science & Engineering,
Southwest Jiaotong University, Chengdu 610031, China;
3. State Key Laboratory of Nonlinear Mechanics Institute of Mechanics,
Chinese Academy of Sciences, Beijing 100080, China;
4. School of Materials Science and Engineering, Chongqing University,
Chongqing 300044, China）
Abstract: The microstructures characteristics of the cold-rolled deformed nanocrystalline Nickel metal were studied by transmission electron microscopy (TEM).The results show that, after cold-rolled deformation, the average grain size is about 50-70 nm. Few of dislocations are found in the deformed microstructure. There are step structures in the grain boundary (GB) and neighborhood area, and the contrast of stress field ahead of the step corresponds to the step in the shape. In the late stage of the deformation, with the grain size growing up, the grain boundary can emit partial dislocations. The partial dislocations promote the creation of stack faults, and the size of the stack faults grows up with the gliding of the partial dislocation, so, it is easy to realize the deformation. When the size of stack dislocations grows up, the local deformation stress ahead of the step gradually become big. When this stress reaches a critical value, the gliding of the partial dislocations stops, the stack faults will stop growing up and leave the step structure behind.
Key words: nanocrystalline; microstructure; deformation; stack fault; dislocation
