Nucleation and growth of H blisters in stacking fault on B2-FeAl {100} planes
Nucleation and growth of H blisters in stacking fault on B2-FeAl {100} planes
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B2-FeAl {100}面上堆垛层错中H气泡的形核和生长
DOI：
10.1039/c7ra08368h
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发表时间：
2017
期刊：
影响因子：
3.9
通讯作者：
Tang Tao
中科院分区：
文献类型：
--
作者：
Zhang Guikai;Yang Feilong;Hu Meijuan;Liu Lang;Luo Zhaoyi;Tang Tao
本文采用第一性原理计算方法研究了B2-FeAl合金{100}面层错处的氢积累行为。结果表明，B2-FeAl {100}面上的SF可以捕获H原子，并作为H泡的形核位置。当被捕获的氢的面密度（每平方厘米的截面积上的氢原子数）高达5.9 × 1015个原子时，氢就会重新结合成分子。随着被捕获的氢原子的进一步增加，氢泡逐渐长大，产生3.4GPa的氢压力，并且显著地使SF附近的Al-Al键伸长70%，这意味着裂纹的开始，并且最终导致宏观断裂和实验观察到的{100}型裂纹。这为铁铝化合物中氢泡的HE机制提供了理论依据。
In the present work, the H accumulating behaviors at the stacking fault (SF) on {100} planes in B2–FeAl are studied by first-principles calculations. It is concluded that the SF on B2–FeAl {100} planes can trap H atoms, which serve as nucleation sites for H bubbles. When the areal density (the number of H atoms per the cross-sectional area of the SF) of the trapped H is as high as 5.9 × 1015 atoms per cm2, hydrogen recombines into molecules. With further increasing trapped H atoms, H bubbles grow gradually, yielding a hydrogen pressure of 3.4 GPa and strikingly elongating Al–Al bonds near the SF by 70% which implies the initiation of a crack, and eventually leads to a macroscopic fracture and crack of {100} type observed experimentally with the build-up of high pressures of hydrogen gases. This provides theoretical evidence for a HE mechanism of hydrogen blisters in iron aluminides.