Mechanical criterion for nucleation of intergranular stress corrosion cracking in austenitic stainless steel
Mechanical criterion for nucleation of intergranular stress corrosion cracking in austenitic stainless steel
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DOI：
10.1016/j.finmec.2021.100013
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发表时间：
2021
期刊：
影响因子：
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通讯作者：
T. Fujii;T. Sawada;K. Tohgo;Y. Shimamura
中科院分区：
文献类型：
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作者：
T. Fujii;T. Sawada;K. Tohgo;Y. Shimamura
研究了热敏感型304奥氏体不锈钢晶间应力腐蚀开裂(IGSCC)形核的力学判据。在四硫酸盐溶液中对不锈钢试件进行了恒载试验，并对试件表面的裂纹萌生、聚结和晶界生长等裂纹行为进行了原位观察。通过数字图像相关(DIC)技术测量光滑表面上沿GBs的局部正常应变。采用Schmid型修正晶界应力(SMGBS)模型估算了晶界的局部正应力，该模型考虑了晶界附近颗粒的平面几何形状和取向的影响，被广泛用于评价晶界应力状态。讨论了IGSCC形核位置、应变和应力之间的关系。结果表明，SMGBS模型测得的局部法向应力与DIC法测得的局部法向应变之间存在一定的相关性。用实验测得的局部法向应变来表征IGSCC形核位置是合适的。
This study investigated mechanical criteria for the nucleation of intergranular stress corrosion cracking (IGSCC) in thermally-sensitized type 304 austenitic stainless steel. Constant load testing was conducted on a stainlesssteel specimen in a tetrathionate solution, and the cracking behavior, including crack initiation, coalescence, and growth at grain boundaries (GBs) on the specimen surface, was observed in situ. Local normal strains along GBs were measured on the smooth surface via the digital image correlation (DIC) technique. Local normal stresses at GBs were estimated using the Schmid-modified grain boundary stress (SMGBS) model, which has been widely used for evaluating the stress state of GBs, considering the effect of the GB plane geometry and grain orientations of grains adjacent to the GBs. The relationship between IGSCC nucleation sites, strains, and stresses was discussed. As a result, there was a slight correlation between local normal stress obtained via the SMGBS model and local normal strain via DIC measurement. The use of experimentally measured local normal strain was found to be suitable to characterize IGSCC nucleation sites.