The corrosion-enhanced plasticity model for stress corrosion cracking in ductile fcc alloys

Critical experiments are presented to test the corrosion enhanced plasticity model proposed some years ago by one of the present authors to describe the SCC of austenitic stainless steels in Cl- solutions. Slow strain rate tests on [110] and [100] 316 L alloy single crystals clearly confirm that the macroscopically brittle fracture is in fact achieved by microcracking on {111} microfacets in a zig-zag manner. Moreover the corrosion-deformation interactions on which the model is based are quantitatively analysed through softening effects observed during cyclic plastic deformation in the corrosive solution. The conditions for hydrogen entry into the material are described, which leads to the notion of critical surface defects for hydrogen effects. New developments of the model are discussed in the case of fee ductile alloys.