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.

Figure optionsDownload as PowerPoint slide