Passive film-induced stress and mechanical properties of α-Ti in methanol solution

•Tensile stress is generated by the passive film during α-Ti corrosion in methanol solution.•Water reduces film-induced stress and passive film breaking load in methanol.•Water reduces α-Ti SCC susceptibility in methanol solution.•The easier passive film can be broken, the more likely SCC would happen.•Film residual stress is reasonably estimated.

Passive films play an important role in corrosion and stress corrosion cracking of titanium. Correlation between passive film-induced stress and film mechanical properties on α-Ti in methanol solution with varying water content was investigated. Film-induced stress in the methanol solution was measured by the flow stress differential method, and thin film fracture properties were determined by nanoindentation. For small amounts of water (⩽0.15%), both film-induced tensile stress and film fracture load were higher. However, the film-induced tensile stress and fracture load decreased significantly in more dilute solutions. Thus, water reduces Ti SCC susceptibility in methanol solution.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slide