Evaluation of hydrogen trapping mechanisms during performance of different hydrogen fugacity in a lean duplex stainless steel
Evaluation of hydrogen trapping mechanisms during performance of different hydrogen fugacity in a lean duplex stainless steel
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DOI：
10.1016/j.jallcom.2015.07.029
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发表时间：
2015-11
影响因子：
6.2
通讯作者：
R. Silverstein;D. Eliezer;B. Glam;S. Eliezer;D. Moreno
中科院分区：
文献类型：
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作者：
R. Silverstein;D. Eliezer;B. Glam;S. Eliezer;D. Moreno
用热脱附谱（TDS）研究了贫双相不锈钢（LDS）中氢的捕集行为。金属对氢脆的敏感性与陷阱的特性直接相关：源或汇（分别为可逆或不可逆）。由于捕获影响金属的扩散性，因此它对氢辅助开裂（HAC）现象有重大影响。从以前发表的作品中可以看出，磁化率将取决于可逆和不可逆陷阱之间的竞争;这意味着与钢中氢的初始状态直接相关。本文利用TDS分析了LDS在不同充氢环境下的捕集机理。通过X射线衍射（XRD）、氢定量测量和显微结构观察，支持并证实了TDS分析。研究发现，与阴极充电（产生更高的氢逸度）相比，气态充电（产生更低的氢逸度）产生的氢捕获活化能高出0.22%。这些结果是由于LDS中氢行为的不同影响导致氢含量的主要差异和不同的氢辅助相变。在阴极充电样品中最高的活化能值归因于主要的γ → γ δ相变，而在气态充电样品中则归因于主要的金属间化合物σ（σ）的形成。详细讨论了氢在LDS中的分布与氢捕获机理的关系。
Hydrogen trapping behavior in a lean duplex stainless steel (LDS) is studied by means of thermal desorption spectrometry (TDS). The susceptibility of a metal to hydrogen embrittlement is directly related to the trap characteristics: source or sink (reversible or irreversible, respectively). Since trapping affects the metal's diffusivity, it has a major influence on the hydrogen assisted cracking (HAC) phenomenon. It is known from previously published works that the susceptibility will depend on the competition between reversible and irreversible traps; meaning a direct relation to the hydrogen's initial state in the steel. In this research the trapping mechanism of LDS, exposed to different hydrogen charging environments, is analyzed by means of TDS. The TDS analysis was supported and confirmed by means of X-ray diffraction (XRD), hydrogen quantitative measurements and microstructural observations. It was found that gaseous charging (which produces lower hydrogen fugacity) creates ∼22% higher activation energy for hydrogen trapping compared with cathodic charging (which produces higher hydrogen fugacity). These results are due to the different effects on the hydrogen behavior in LDS which causes a major difference in the hydrogen contents and different hydrogen assisted phase transitions. The highest activation energy value in the cathodic charged sample was ascribed to the dominant phase transformation of γ → γ∗, whereas in the gaseous charged sample it was ascribed to the dominant formation of intermetallic compound, sigma (σ). The relation between hydrogen distribution in LDS and hydrogen trapping mechanism is discussed in details.