II - Nouveaux éléments en faveur du modèle d’interaction corrosion - déformation en CSC

Experiments supporting the corrosion enhanced plasticity model

Abstract

Critical experiments have been performed to test the corrosion enhanced plasticity model proposed some years ago by T. Magnin [1]. Slow strain rate test and four points bending test on <110> and <410> 316L alloy single crystals clearly show that the macroscopically brittle fracture on the average (110) and (100) plane is in fact achieved by microcracking on {111} facets in zig-zag which is in perfect agreement with the model. The first stage of the model is also confirmed : cracks initiate inside the {111} slip band as a consequence of a localised dissolution in the {111} slip lines. Finally the hypothesis of an enhanced plasticity due to the anodic dissolution is verified. A corrosion fatigue test on 316L shows that when anodic dissolution is favoured then, at a macroscopic scale, a softening effect can be detected : it is due to vacancies which enhanced dislocations mobility.