氦泡对Cu/Nb层状材料界面拉伸屈服强度影响的分子模拟  

Atomistic simulation of the effect of helium bubbles on interface tensile yield strength of Cu/Nb layered material

作　　者：张雅宁 吕陈扬韬 楚海建[1,2,3] ZHANG Yaning;LU¨-CHEN Yangtao;CHU Haijian(School of Mechanics and Engineering Science,Shanghai University,Shanghai 200444,China;Shanghai Institute of Applied Mathematics and Mechanics,Shanghai University,Shanghai 200072,China;Shanghai Key Laboratory of Energy Engineering Mechanics,Shanghai University,Shanghai 200444,China)

机构地区：[1]上海大学力学与工程科学学院,上海200444 [2]上海大学上海市应用数学和力学研究所,上海200072 [3]上海大学上海市能源工程力学重点实验室,上海200444

出　　处：《上海大学学报（自然科学版）》2024年第5期904-912,共9页Journal of Shanghai University:Natural Science Edition

基　　金：国家自然科学基金资助项目(11872237);上海市自然科学基金资助项目(18ZR1414600);国防基础科研科学挑战专题项目(GAEP)。

摘　　要：基于分子动力学方法模拟研究了含氦泡Cu/Nb层状材料的界面拉伸屈服强度,考察了氦泡内压、氦泡尺寸和层厚对界面拉伸屈服强度及其变形机理的影响.研究结果发现,界面氦泡可以诱导界面位错成核,改变层状材料微观演化过程,显著降低了Cu/Nb层状材料的界面拉伸屈服强度.界面拉伸屈服强度随氦泡直径增大而减小,表现出明显的尺寸效应.典型的3 nm直径的平衡氦泡使得界面拉伸屈服强度(上屈服极限)相对于无氦泡情况降低约12%,而直径为6 nm的平衡氦泡使得界面拉伸屈服强度下降约33%.研究还发现,层厚对Cu/Nb层状材料的上屈服极限影响甚微,而对下屈服极限影响显著.前者归因于Cu/Nb界面的结构对称性和加载方式的对称性,使得界面应力及位错成核应力对层厚不敏感;后者则归因于层厚的增加给位错运动和演化提供了更大的空间,导致应力在屈服阶段的快速下降.The interfacial tensile yield strengths of Cu/Nb layered materials containing helium bubbles are investigated via molecular dynamics simulations.Specifically,the effects of helium bubble internal pressure,bubble size,and layer thickness on the interface tensile yield strength and deformation mechanism of Cu/Nb layered materials are investigated.Results show that interface helium bubbles can induce interface dislocation nucleation,change the microstructural evolution,and significantly reduce the interface tensile yield strength of Cu/Nb layered materials.The effect of helium bubbles on the interface tensile yield strength weakens as the helium bubble size increases resulting in apparent size effect.Compared with the case without helium bubbles,the interface tensile yield strength reduced by approximately 12%and 33%for the models containing 3 and 6 nm helium bubbles,respectively.Additionally,the layer thickness minimally affects the upper yield stress of the Cu/Nb-layered materials,whereas it significantly affects the lower yield stress.The former is attributed to the structure symmetry of the Cu/Nb interface and the loading symmetry,which render the interface stress and dislocation nucleation stress insensitive to the layer thickness.The latter is due to the increased layer thickness,which provides more space for dislocation motion and evolution,thus resulting in rapid stress reduction during the yield period.

关 键 词：氦泡 界面拉伸屈服强度 Cu/Nb层状材料 分子动力学方法 

分 类 号：O369[理学—流体力学]