Insights into the effects of δ-ferrite on crack tip stress/strain and stress corrosion cracking propagation behavior of austenite weld metal: A numerical and experimental study

Abstract

The effects of δ-ferrite on stress corrosion cracking behaviors of austenite weld metal were analyzed by a ferrite-crack model. The results show that the δ-ferrite might inhibit the crack propagation initially once the crack tip meets it by reducing the local plastic strains. Thereafter, the crack might still propagate either along the δ-ferrite boundary (intergranular, IG) or across the δ-ferrite (transgranular, TG). The IG cracking will accumulate much more plastic strains at the crack tip and tends to promote crack growth. The TG cracking might be enhanced by the oxidation-induced embrittlement of the δ-ferrite.