Hydrogen-enhanced vacancy embrittlement of grain boundaries in iron
Hydrogen-enhanced vacancy embrittlement of grain boundaries in iron
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DOI：
10.1103/physrevb.88.144107
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发表时间：
2013-10-21
影响因子：
3.7
通讯作者：
Ohno, Takahisa
中科院分区：
文献类型：
--
作者：
Momida, Hiroyoshi;Asari, Yusuke;Ohno, Takahisa
我们利用第一性原理计算研究了存在和不存在空位时铁晶界处氢脆的原子和电子机制。考虑到α - fe中氢、空位和Sigma 3晶界之间的相互作用，我们通过评估它们在静态拉伸应变下对拉伸强度的影响来寻找最有害的缺陷状态。计算结果表明，氢和空位倾向于在晶界附近以缺陷络合物的形式积累，从而降低了晶界的抗拉强度。理论应力-应变曲线表明，缺陷复合体在晶界处的强度降低效应远大于各因素的影响。由于空位的低迁移率，这一机制可以解释氢在钢材料中引起的延迟脆性断裂。
We have investigated atomistic and electronic mechanisms of hydrogen embrittlement at grain boundaries of iron in the presence and absence of vacancies by using first-principles calculations. Considering interactions between hydrogen, vacancies, and Sigma 3 grain boundaries in alpha-Fe, we have searched for the most deleterious defect states by evaluating their influence on tensile strength under static tensile strain. The calculated results show that hydrogen and vacancies prefer to accumulate as defect complexes near grain boundaries, thereby decreasing the tensile strength of grain boundaries. Theoretical stress-strain curves show that a strength lowering at grain boundaries by the defect complexes is found to be much worse than the effect of each factor. Because of the low mobility of vacancies, this mechanism can account for the delayed brittle fractures induced by hydrogen in steel materials.