Zhu Longkui
Beijing Institute of Structure and Environment Engineering, China Academy of Launch Vehicle Technology, China Aerospace Science and Technology Corporation, Beijing, 100076, China.
Sci Rep. 2022 Jul 20;12(1):12390. doi: 10.1038/s41598-022-16390-1.
Stress corrosion cracking (SCC) of non-sensitized austenitic stainless steel during immersion of MgCl solutions was investigated by X-ray computed tomography and scanning electron microscopy. SCC cracks propagated transgranularly at the initial stage, and switched to the IGSCC mode under the high constant load. There was no ductile dimple present on the SCC fractography, but numerous cleavage facets, slip bands and pits emerged. The cohesive zone appeared ahead of the crack tip. It is indicated that the high-load SCC also coincides with the cleavage dissolution mechanism, predominantly originating from the corrosive environment particle assisted cleavage and the obstacle induced dislocation pinning.
通过X射线计算机断层扫描和扫描电子显微镜研究了非敏化奥氏体不锈钢在MgCl溶液浸泡过程中的应力腐蚀开裂(SCC)。SCC裂纹在初始阶段沿穿晶扩展,在高恒定载荷下转变为晶间应力腐蚀开裂(IGSCC)模式。SCC断口上没有韧性韧窝,但出现了大量解理面、滑移带和蚀坑。在裂纹尖端前方出现了内聚区。结果表明,高载荷SCC也符合解理溶解机制,主要源于腐蚀环境颗粒辅助解理和障碍物诱导的位错钉扎。