Analysis of the early stage of stress corrosion cracking in austenitic stainless steel by EBSD and XRD
Analysis of the early stage of stress corrosion cracking in austenitic stainless steel by EBSD and XRD
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DOI：
10.1016/j.matchar.2021.110882
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发表时间：
2021-02
影响因子：
4.7
通讯作者：
T. Fujii;Ryohei Yamakawa;K. Tohgo;Y. Shimamura
中科院分区：
文献类型：
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作者：
T. Fujii;Ryohei Yamakawa;K. Tohgo;Y. Shimamura
本研究基于微观结构评估，使用 X 射线衍射 (XRD) 和电子背散射衍射 (EBSD) 检查了敏化奥氏体不锈钢应力腐蚀开裂 (SCC) 早期阶段的成核行为。 SCC 实验是在连四硫酸盐溶液中施加相当于 2% 初始应变的恒定负载时进行的。测试前后通过 EBSD 测定热敏化样品光滑表面上的晶体取向，并使用 XRD 间歇性检查衍射斑点。一些具有高施密德因子的晶粒被发现由于腐蚀溶液中恒定的拉伸载荷而在晶界（GB）附近发生局部变形，从而在这些晶界处发生晶间应力腐蚀裂纹。这项工作的结果表明，金属上的钝化膜首先由于局部变形而破裂，然后靠近晶界的新形成的表面暴露在腐蚀溶液中。随后，局部裂纹状腐蚀在晶界附近的贫铬区进行，产生晶间应力腐蚀开裂。
This study examined nucleation behavior during the early stage of stress corrosion cracking (SCC) in sensitized austenitic stainless steel based on microstructural assessments, using X-ray diffraction (XRD) and electron back-scattered diffraction (EBSD). The SCC experiment was conducted while applying a constant load corresponding to an initial strain of 2% in a tetrathionate solution. The crystal orientations on the smooth surface of a thermally sensitized specimen were determined via EBSD before and after testing, and diffraction spots were intermittently examined using XRD. Some grains having a high Schmid factor were found to be locally deformed near grain boundaries (GBs) due to constant tensile loading in the corrosive solution, such that intergranular stress corrosion cracks occurred at these GBs. The results of this work demonstrate that the passivation film on the metal first fractures due to localized deformation, after which newly created surfaces near GBs are exposed to the corrosive solution. Localized crack-like corrosion subsequently proceeds in chromium-depleted zones near GBs to generate intergranular SCC.