AgCl-induced hot salt stress corrosion cracking in a titanium alloy

The mechanism of AgCl-induced stress corrosion cracking of Ti-6246 was examined at \SI{500}{\mega\pascal} and \SI{380}{\celsius} for \SI{24}{\hour} exposures. SEM and STEM-EDX examination of a FIB-sectioned blister and crack showed that metallic Ag was formed and migrated along the crack. TEM analysis also revealed the presence of \ce{SnO2} and \ce{Al2O3} corrosion products mixed into \ce{TiO2}. The fracture surface has a transgranular and brittle appearance with cleavage-like cracking of the $\alpha$ phase. Long, straight and non-interacting dislocations were observed in a cleavage-fractured primary $\alpha$ grain, with basal and pyramidal traces. This is consistent with a dislocation emission view of the the cracking mechanism.