Strain-rate dependence of hydrogen-induced defects in pure α-iron by positron annihilation lifetime spectroscopy
Strain-rate dependence of hydrogen-induced defects in pure α-iron by positron annihilation lifetime spectroscopy
复制标题
通过正电子湮灭寿命光谱研究纯 α-铁中氢致缺陷的应变率依赖性
DOI：
10.1016/j.msea.2020.140281
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Fujinami Masanori
中科院分区：
文献类型：
--
作者：
Chiari Luca;Nozaki Ayaka;Koizumi Kazuki;Fujinami Masanori
利用变温正电子湮没寿命谱研究了室温下不同拉伸应变速率下充氢纯铁中缺陷的形成，以阐明氢致缺陷在氢脆机制中的作用。一个明显的应变速率依赖性的氢相关的缺陷进行了观察和氢脆化铁和非脆化铁中形成的缺陷之间的明显差异进行了检测。在氢脆慢应变铁，低温测量表明，形成较小的空位簇比非脆快应变铁。随着退火温度的升高，这些缺陷长大成更大的空位团。这些结果表明，在氢脆铁，空位团稳定的氢积累在局部高浓度。该条件是氢脆发生的充分条件和临界条件。这一结果代表了朝着全面理解铁的氢脆机理迈出的关键一步。
The formation of defects in hydrogen-charged pureα-iron deformed at room temperature at different tensile strain rates was investigated by variable-temperature positron annihilation lifetime spectroscopy to clarify the role of hydrogen-induced defects in driving the hydrogen embrittlement mechanism. A distinct strain-rate dependence of the hydrogen-related defects was observed and a clear difference between the defects formed in hydrogen-embrittled iron and non-embrittled iron was detected. In hydrogen-embrittled slowly strained iron, the low-temperature measurements showed the formation of smaller vacancy clusters than in non-embrittled fast strained iron. With increasing annealing temperature, these defects grew into larger vacancy clusters. These results suggest that, in hydrogen-embrittled iron, vacancy clusters stabilized by hydrogen accumulated locally in high concentrations. This condition is found to be the a sufficient and critical condition to trigger the hydrogen embrittlement. This result represents a crucial step forward towards a comprehensive understanding of the hydrogen embrittlement mechanism in iron.