Effect of multiple hydrogen embrittlement mechanisms on crack propagation behavior of FCC metals: Competition vs. synergy
Effect of multiple hydrogen embrittlement mechanisms on crack propagation behavior of FCC metals: Competition vs. synergy
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多种氢脆机制对 FCC 金属裂纹扩展行为的影响：竞争与协同
DOI：
10.1016/j.ijplas.2021.103023
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发表时间：
2021
影响因子：
9.8
通讯作者：
Zhenhuan Li
中科院分区：
文献类型：
--
作者：
Shuang Liang;Minsheng Huang;Lv Zhao;Yaxin Zhu;Zhenhuan Li
在不同的金属材料中，由于氢而引起的早期失效已经被广泛观察到。氢如何影响脆性解理与韧性断裂的竞争是一个重要的科学问题。解决这一问题的关键是定量描述氢与金属中各种缺陷的相互作用。在目前的工作中，四个原子通知的中尺度模型，定量描述四个广泛使用的氢脆（HE）机制，建立DFT或MD模拟，然后集成到基于XFEM的DDD框架。在此多尺度框架下，研究了面心立方Al和Ni的氢致沿晶断裂，并与典型的孪晶界（TB）和大角度晶界（HAGB）进行了对比。计算结果表明，当多种HE机制共存并相互作用时，不同金属中占主导地位的HE机制取决于GB类型。与HAGB相比，TB具有更好的抗氢脆性能。在Al和Ni中，裂纹沿着TB扩展的主要机制是吸附诱导位错发射（AIDE）机制，而裂纹沿着HAGB扩展的主要机制是氢增强脱粘（HEDE）机制。与HEDE和AIDE机制相比，弹性屏蔽（ES）和氢增强应变诱导空位（HESIV）对氢致沿晶断裂的影响要弱得多，除非氢浓度异常高。这些结果有助于我们理解氢脆现象背后复杂的物理机制。
Premature failure due to hydrogen has been widely observed in different metallic materials. How does hydrogen affect the competition between brittle cleavage and ductile fracture is an important scientific question to be addressed. The key to solve this problem is to quantitatively depict the interactions between hydrogen and various defects in metals. In the present work, four atomically-informed mesoscale models which depict quantitatively four widely used hydrogen embrittlement (HE) mechanisms are established by DFT or MD simulations, and then integrated into the XFEM-based DDD framework. By this multi-scale framework, hydrogen-induced intergranular fracture in FCC Al and Ni is investigated, with typical twin boundary (TB) and high angle grain boundary (HAGB) considered for comparison. Computational results show that the dominant HE mechanism in different metals depends on the GB type when multiple HE mechanisms coexist and interact with each other. Compared with the HAGB, the TB has better resistance to hydrogen embrittlemen. The adsorption-induced dislocation emission (AIDE) mechanism dominates the crack propagation along the TB in Al and Ni, while the hydrogen-enhanced decohesion (HEDE) mechanism dominates the crack propagation along the HAGB in Al and Ni. Compared with the HEDE and AIDE mechanisms, the other two mechanisms, i.e., the elastic shielding (ES) and the hydrogen-enhanced strain-induced vacancy (HESIV), have much weaker effect on the hydrogen-induced intergranular fracture, unless the hydrogen concentration is unusually high. These results are helpful for us to understand the complex physical mechanisms behind the hydrogen embrittlement phenomenon.