Synergistic Effects of Hydrostatic Pressure and Dissolved Oxygen on the SCC Behavior of Hydrogenated Ti6Al4V Alloy in Deep-Sea Environment

This work focused on the synergistic effect of hydrostatic pressure (HP) within the range of 0.1 similar to 50 MPa and a dissolved oxygen (DO) concentration within the range of 0.18 similar to 11.8 ppm on the stress corrosion cracking (SCC) behavior of hydrogenated Ti6Al4V alloy in a simulated deep-sea environment by electrochemical measurements and slow strain rate tensile (SSRT) tests. The potentiodynamic polarization and electrochemical impedance spectra results confirmed the corrosion resistance degradation with the HP increasing to 50 MPa. The fracture morphologies showed a mixed characteristic of brittle fracture on the surface layer and ductile fracture in the inner part. Higher HPs increased SCC susceptibility while a larger DO concentration decrease that of Ti6Al4V alloy.