材料表面のひずみ分布に基づく応力腐食割れの発生挙動評価

抄録

Stress corrosion cracking (SCC) is caused by a specific combination of applied stress, environment and material. This study deals with the nucleation of SCC in sensitized type 304 austenitic stainless steel based on a strain-based approach. Prior to testing, strain distributions on a specimen surface subjected to an applied strain of 1% were measured by the digital image correlation technique. Then, SCC testing was conducted in a tetrathionate solution under a constant load corresponding to the initial strain of 1%. After testing, crystal orientation on the specimen surface was measured by the electron backscattered diffraction technique, and the relationship between grain boundary character and strains at cracked and uncracked grain boundaries were investigated. As a result, stress corrosion cracks tended to preferentially initiate at the random boundaries where normal strain, shear strain or both strains were high.