Dislocation dynamics analysis of hydrogen embrittlement in alpha iron based on atomistic investigations
Hydrogen embrittlement is well known phenomenon in which hydrogen lowers the strength of materials.Hydrogen atoms show unique characteristics such as high diffusivity and low concentration in metals,so the direct observations of hydrogen effects on mechanical properties are still difficult.Nevertheless,experimental studies have been revealed many valuable results; HEDE (Hydrogen Enhanced Decohesion),HELP (Hydrogen Enhanced Localized Plasticity),HESIV (Hydrogen Enhanced Strain Induced Vacancy) and others have been proposed as a fracture mechanism of hydrogen embrittlement so far.However,the overview of the hydrogen embrittlement under various conditions is still unclear.In this study,we focus on the edge dislocation motion in the presence of hydrogen atom as one of the elementary process of hydrogen embrittlement in alpha iron.Our previous studies showed that the dislocation velocity increace (softening) occurs at lower hydrogen concentration and lower applied stress conditions.In contrast,dislocation velocity decrease (hardening) occurs at higher hydrogen concentration or higher applied stress conditions.Therefore,we performed the dislocation dynamics calculation around a crack tip based on the results obtained by our atomistic calculations.The results indicate that the hydrogen embrittlement mechanisms possibly change depending on boundary conditions (hydrogen concentration and applied stress intensity factor rate).
Hydrogen embrittlement Dislocation dynamics Atomistic simulation Alpha iron
Shinya Taketomi Honami Imanishi Ryosuke Matsumoto Noriyuki Miyazaki
Department of Mechanical Engineering,Saga University,840-8502,Japan Department of Mechanical Engineering and Science,Kyoto University,606-8501,Japan
国际会议
北京
英文
1-9
2013-06-16（万方平台首次上网日期，不代表论文的发表时间）