单晶Pt中位错与非共格孪晶界反应的原位原子尺度观察  

In situ atomic⁃scale observation of dislocation reaction with incoherent twin boundary in Pt thin films

作　　者：郭谊忠 李帅 王占鑫 李雪峤 王立华[1] 韩晓东[1] GUO Yi-zhong;LI Shuai;WANG Zhan-xin;LI Xue-qiao;WANG Li-hua;HAN Xiao-dong(Beijing Key Lab of Microstructure and Property of Advanced Material,Beijing University of Technology,Beijing 100124,China)

机构地区：[1]北京工业大学固体微结构与性能研究所,北京市重点实验室,北京100124

出　　处：《电子显微学报》2022年第4期363-369,共7页Journal of Chinese Electron Microscopy Society

基　　金：国家重点研发计划(No.2021YFA1200201);北京市卓越青年科学家计划(No.BJJWZYJH01201910005018);国家基础科学中心资助项目(No.51988101);国家自然科学基金资助项目(No.12174014).

摘　　要：非共格孪晶界(incoherent twin boundary,ITB)是金属中一种重要的晶界结构,其原子层次结构对金属的力学性能有显著影响。之前虽有一些关于ITB的结构演化及动态行为研究报道,但ITB与全位错相互反应导致ITB结构变化的原位研究还很少见,相关的原子层次机制仍然不清楚。本文以具有高密度生长孪晶的Pt薄膜为研究对象,利用高角环形暗场像揭示了Pt薄膜中ITB的原子结构。在原子层次原位观察到了全位错向ITB运动靠近,然后被ITB吸收的过程。原子尺度的位移分布测量表明全位错向ITB靠近的过程中就会引起ITB结构的变化。分子动力学模拟以及能量计算结果揭示出全位错容易被ITB吸引,然后形成了新的ITB结构而降低系统能量,这一结果很好地解释了这种新ITB结构在生长的薄膜中经常被观察到的原因。Incoherent twin boundary(ITB)is an important type of grain boundaries in metals,and its atomic⁃scale structures can significantly affect the mechanical properties of metals.Although there are some reports on the microstructural dynamic evolution of ITB,the in⁃situ atomic⁃scale study on the structural evolution of ITB induced by the interaction of full dislocation with ITB is still lacking,and the relevant atomistic mechanism is still unclear.In this paper,the atomic⁃scale structure of ITB in Pt thin films with high⁃density growth twins was investigated by using high⁃angle dark⁃field imaging technique.We found that full dislocations moved towards ITBs and adsorbed by these ITBs at atomic scale in real time.Atomic⁃scale displacement maps show that the motion of full dislocation towards ITBs can cause the change of ITB structures.Molecular dynamics simulation reveals that full dislocations are easily attracted by ITBs,and followed by the generation of new ITBs in order to lower the total energy of the system.Our result here provide a clear picture for understanding why new ITB structures in thin films can be frequently observed.

关 键 词：Pt薄膜 全位错 非共格孪晶界 原子尺度 高角环形暗场像 原位 

分 类 号：O76[理学—晶体学] O482[一般工业技术—材料科学与工程] TB34[金属学及工艺—物理冶金] TG115.215.3[金属学及工艺—金属学]