单晶体心立方金属铌裂纹尖端位错增殖行为的原位研究  

In-situ TEM investigation of dislocation multiplication in front of crack in body-centered cubic single crystal niobium

作　　者：舒新愉 卢艳[1] 王立华[1] 陈艳辉[1] 周浩[1] 张泽[1,2] 韩晓东[1] 

机构地区：[1]北京工业大学固体微结构与性能研究所,北京100124 [2]浙江大学电子显微镜中心,材料科学与工程学院,浙江杭州310027

出　　处：《电子显微学报》2017年第4期313-320,共8页Journal of Chinese Electron Microscopy Society

基　　金：国家自然科学基金重点资助项目(No.11234011,No.51231008);国家自然科学基金资助项目(No.11374030,No.11327901,No.11127404,No.51471008,No.1L102001201401);北京市科技新星项目(Z1511000003150142,Z141103001814108);北京市高校创新团队建设与教师职业发展项目(IDHT20140504);北京PXM201101420409000053及北京211工程;霍英东教育基金(No.151006);高等学校博士学科点专项科研基金(No.3C102001201301);北京市属高等学校高层次人才引进与培养计划项目(CIT&TCD201504013)

摘　　要：位错的增殖对体心立方金属材料的塑性性能有着非常重要的意义,目前对于体心立方位错增殖机制的动态研究主要依赖于计算模拟,实验研究很少见到报道,其位错增殖机制尚存在不确定性。本文利用透射电镜原位拉伸技术,实现了单晶体心立方金属铌(Nb)裂纹尖端位错增殖的原位动态实验观察,并提出了两个位错模型来解释位错增殖以及运动的机制。从实验上不仅证实了之前模拟的预测,而且对现有的模型进行了很好的补充,为体心立方金属材料的塑性变形机制提供了基础实验数据。Abastract Dislocation multiplication is important to the plasticity of body-centered cubic( BCC) metals. However,relevant studies mainly focused on theoretical simulations,which need further experimental evidence to support. In this work,the dislocation multiplication in front of crack in BCC single crystal Nb was revealed by in-situ transmission electron microscopy technique.Such dislocation multiplication resulted from frequent cross-slip of screw components of dislocation loops and their annihilation by dislocation interaction. A new dislocation loop can be formed during this multiplication process. Two models are provided in this work to describe the dislocation multiplication process and the new-born dislocation loop activities. Results in this work are in good agreement with previous simulations. The dislocation multiplication process in this work provides better understanding of dislocation theory of BCC metals.

关 键 词：体心立方 位错增殖 单晶铌 原位 

分 类 号：TG146.416[一般工业技术—材料科学与工程]