The influences of applied stress, test temperature, and concentration on environment-induced cracking of Ni3 (Si,Ti) intermetallic compound in neutral sodium chloride solutions

The environment-induced cracking (EIC) behavior of Ni3 (Si,Ti) intermetallic compound was investigated as functions of applied stress, test temperature and chloride-ion concentration in NaCl solution by using a constant load method. From the applied stress dependence of the three parameters (tf, lss and tss/tf ), the relationships were found to be divided into three regions : stress, EIC and corrosion dominated regions. The ratio of tss/tf in the EIC-dominated region was constant independent of applied stress, test temperature and chloride-ion concentration. Furthermore, the relationship between log tf and log lss in the EIC-dominated region became a good straight line irrespective of applied stress, test temperature and chloride-ion concentration. The fracture appearance in the EIC-dominated region was intergranular. On the basis of the results obtained, an intergranular EIC was supposed in terms of hydrogen entry, dissolution and film formation. Article in press, 2014