纳米结构金属位错的研究进展  

Research Progress on Dislocations of Nanostructured Metals

作　　者：倪海涛[1] 张喜燕[1] 朱玉涛[1] 

机构地区：[1]重庆大学材料科学与工程学院,重庆400044

出　　处：《材料导报》2010年第11期112-115,共4页Materials Reports

基　　金：国家自然科学基金(50461001)

摘　　要：综述了国内外近年来对纳米结构金属位错的研究,包括位错的基本特征、研究方法以及定量分析。由于晶粒尺寸的减小,全位错的形成和运动变得困难甚至不可能,纳米结构金属更容易生成不全位错。在高分辨TEM图像观察实验中发现了大量孪晶或层错,也证实了不全位错的存在。着重讨论了晶界发射不全位错的形核、增殖以及在塑性变形过程中所起的作用。研究了纳米结构金属中的位错动力学,采用分子动力学模拟和高分辨透射电镜方法从不同层面上揭示了位错的形核、增殖、运动以及相互作用等过程。最后简单介绍了位错柏氏矢量以及密度的相关定量分析,其相关参数的表征对进一步弄清纳米结构金属的塑性变形机制具有重要意义。The research on dislocations of nanostructured metals in recent years is reviewed, including the basic characteristics, research methods and quantitative analysis. According to the dislocation theories, with the decrease of grain size, the formation and movement of perfect dislocation will get more difficult, even impossible. Therefore, par- tial dislocations are usually found in nanostructured metals. Plenty of deformation twins or stacking faults are observed in nanostruetured metals by high resolution transmission electron microscopy, indicating the presence of partial dislo- cation activities. Nucleation and propagation of partial dislocations emitted from grain boundaries and the role of dislo- cations during plastic deformation are emphasized. To make clear the dislocation dynamics, molecular dynamics simula- tions and high-resolution transmission electron microscopy are used, from different aspects, to reveal the nucleation, propagation, motion and interaction of dislocations. The burgers vector and density of dislocations are also introduced briefly, which help the understanding of the deformation mechanism involving dislocations.

关 键 词：纳米结构金属 位错 位错密度 

分 类 号：TG174.445[金属学及工艺—金属表面处理]