Hydrogen in trapping states innocuous to environmental degradation of high-strength steels
Hydrogen in trapping states innocuous to environmental degradation of high-strength steels
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DOI：
10.2355/isijinternational.43.520
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发表时间：
2003-01-01
影响因子：
1.8
通讯作者：
Watanuki, R
中科院分区：
文献类型：
--
作者：
Takai, K;Watanuki, R
用热脱附分析(TDA)和慢应变速率试验(SSRT)分离和提取了高强度钢力学性能中对环境无害的捕捉态的氢。TDA测定结果表明，只闭塞氢气的高强度钢在低温(峰1)脱附时，最大应力和塑性伸长率随峰1氢闭塞时间的增加而减小。因此，峰1氢的捕获状态与环境退化直接相关。峰1氢的陷阱激活能为23.4kJ/mol，因此峰1氢对应的是室温下较弱的结合态和扩散态，而TDA分析表明，只封闭高温脱附的氢的高强度钢(峰2)，在峰2氢含量增加的情况下，仍保持了最大的应力和塑性伸长率，这表明峰2氢捕捉态对环境退化是无害的，即使钢中有大量的峰2氢，峰2氢的陷阱激活能为65.0kJ/mol，这表明钢在室温下具有更强的结合态和不可扩散性。陷阱激活能：或峰2氢表明，弹塑性变形过程中应力诱导扩散所需的驱动力能，以及塑性变形过程中位错运动对氢的拖曳所需的能量低于氢与陷阱位之间的结合能。因此，据信峰值2氢不会聚集在裂纹尖端前面，也不会导致环境退化，尽管存在的量高达2.9质量百万分之多，
Hydrogen in trapping states innocuous to environmental degradation of the mechanical properties of high-strength steels has been separated and extracted using thermal desorption analysis (TDA) and slow strain rate test (SSRT). The high-strength steel occluding only hydrogen desorbed at low temperature (peak 1), as determined by TDA, decreases in maximum stress and plastic elongation with increasing occlusion time of peak 1 hydrogen. Thus the trapping state of peak 1 hydrogen is directly associated with environmental degradation. The trap activation energy for peak 1 hydrogen is 23.4 kJ/mol, so the peak 1 hydrogen corresponds to weaker binding states and diffusible states at room temperature, In contrast, the high-strength steel occluding only hydrogen desorbed at high temperature (peak 2), by TDA, maintains the maximum stress and plastic elongation in spite of an increasing content of peak 2 hydrogen, This result indicates that the peak 2 hydrogen trapping state is innocuous to environmental degradation, even though the steel occludes a large amount of peak 2 hydrogen, The trap activation energy for peak 2 hydrogen is 65.0 kJ/mol, which indicates a stronger binding state and nondiffusibility at room temperature. The trap activation energy :or peak 2 hydrogen suggests that the driving force energy required for stress-induced diffusion during elastic and plastic deformation, and the energy required for hydrogen dragging by dislocation mobility during plastic deformation are lower than the binding energy between hydrogen and trapping sites. The peak 2 hydrogen, therefore, is believed to not accumulate in front of the crack tip and to not cause environmental degradation in spite of being present in amounts as high as 2.9 mass ppm,