表面氢对裂纹扩展的影响  

Effect of surface hydrogen on crack propagation

作　　者：李楠[1] 江晓禹[1] LI Nan;JIANG Xiao-Yu(School of Mechanics and Aerospace,Southwest Jiaotong University,Chengdu 610031,China)

机构地区：[1]西南交通大学力学与航空航天学院,成都611756

出　　处：《原子与分子物理学报》2023年第6期177-183,共7页Journal of Atomic and Molecular Physics

基　　金：国家自然科学基金(11472230)。

摘　　要：暴露于含氢环境的金属表面会吸附氢原子,从而影响材料性能,一定情况下会导致氢脆.这篇文章主要通过分子动力学研究氢从α-Fe自由表面扩散到裂纹面的过程、和表面氢对裂纹扩展的影响.结果表明,在室温下,吸附在表面的氢原子很难直接从自由表面扩散到内部成为溶解氢;自由表面的氢原子会逐步向裂纹表面扩散,最后富集在裂纹表面和自由表面.当表面氢浓度较低时,氢对裂纹扩展影响很小,但是当裂纹表面的氢达到一定浓度时,会导致裂纹失稳扩展,造成严重的氢脆.The metal surface exposed to hydrogen-containing environments can adsorb hydrogen atoms,which can affect the properties of the material and,in some cases,lead to hydrogen embrittlement.In this paper,the process of hydrogen diffusion fromα-Fe free surface to the crack surface and the effect of surface hydrogen on crack propagation are mainly studied by molecular dynamics.The results show that at room temperature,it is difficult for the hydrogen atoms adsorbed on the surface to diffuse directly from the free surface to the interior to become dissolved hydrogen;the hydrogen atoms on the free surface will gradually diffuse to the crack surface,and finally concentrate on the crack surface and the free surface.When the surface hydrogen concentration is low,hydrogen has little effect on crack propagation,but when the hydrogen concentration on the crack surface reaches a certain concentration,it will lead to unstable crack propagation,resulting in serious hydrogen embrittlement.

关 键 词：氢脆 裂纹扩展 分子动力学 位错发射 

分 类 号：O482.1[理学—固体物理]