Observation and quantification of the diffusion-induced grain boundary migration ahead of SCC crack tips

摘要

Crack tips prepared from Ni-based alloys after stress corrosion cracking testing in simulated pressurized water reactor primary water have been studied by high-resolution characterization. Diffusion-induced grain boundary migration (DIGM) was observed in all the cracks and its potential role on the crack propagation is discussed in detail. The extent of DIGM observed changed with grain boundary type and alloy composition, which could lead to different extent of retardation effects on the crack propagation. A method is proposed to quantify the role of DIGM on crack propagation based on the results obtained in this work.