Crystallographic and mechanical investigation of intergranular stress corrosion crack initiation in austenitic stainless steel
Crystallographic and mechanical investigation of intergranular stress corrosion crack initiation in austenitic stainless steel
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DOI：
10.1016/j.msea.2019.02.069
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发表时间：
2019-02
期刊：
影响因子：
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通讯作者：
T. Fujii;K. Tohgo;Yota Mori;Yuta Miura;Y. Shimamura
中科院分区：
文献类型：
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作者：
T. Fujii;K. Tohgo;Yota Mori;Yuta Miura;Y. Shimamura
本研究利用结晶学与力学分析探讨304型奥氏体不锈钢光滑表面晶间应力腐蚀破裂（IGSCC）的形核机制。在连四硫酸盐溶液中对热敏化奥氏体不锈钢进行恒载荷试验，原位观察了光滑表面IGSCC的形核行为。然后，晶界（GB）的应力腐蚀裂纹发生的基础上的重合位置晶格模型，GB长度，和应力作用于GB的特征。结果发现，具有以下特征的晶界对IGSCC表现出高的敏感性：晶界对晶间腐蚀（IGC）的抵抗力小，长的晶界，以及经受高正应力的晶界。作用于晶界的剪切应力对IGSCC的形核影响不大。在此基础上，利用晶界对晶间腐蚀的敏感性、晶界长度和作用于晶界上的应力，提出了晶界应力腐蚀裂纹萌生的判据。
This study used crystallographic and mechanical analyses to investigate the nucleation of intergranular stress corrosion cracking (IGSCC) on a smooth surface of type 304 austenitic stainless steel. Constant load testing was conducted on thermally sensitized austenitic stainless steel in a tetrathionate solution, and the nucleation behavior of IGSCC on a smooth surface was observed in situ. Then, grain boundaries (GBs) at which stress corrosion cracks occurred were characterized based on the coincidence site lattice model, GB length, and stress acting on GBs. It was found that GBs with the following characteristics exhibited high susceptibility to IGSCC: GBs with little resistance to intergranular corrosion (IGC), long GBs, and GBs subjected to high normal stress. Shear stress acting on GBs seemed to have little effect on the nucleation of IGSCC. Then, a criterion for intergranular stress corrosion crack initiation was developed using the susceptibility of GBs to IGC, GB length, and the stresses acting on GBs.