Stress corrosion cracking susceptibility and propagation behavior of TC4 titanium alloy in simulated deep-sea environment

This study investigated the effect of stress intensity factors (K I ), dissolved oxygen (DO), and hydrostatic pressure (HP) on the stress corrosion cracking (SCC) behavior of commercial TC4 titanium alloy in the simulated marine environment, including both shallow-sea and deep-sea conditions. Experimental results revealed that transgranular SCC and a few intergranular SCC at specific grain boundaries dominated the crack propagation mode. Higher K I and DO concentrations accelerate SCC growth rates (SCCGRs), while HP enhances corrosion reactions and hydrogen embrittlement. The mechanisms of the SCC crack propagation in different phases were discussed. • Deep-sea environment increases SCC susceptibility of TC4 compared to shallow-sea. • Deep-sea environment decreases corrosion resistance of TC4 compared to shallow-sea. • SCCGR of TC4 increases with K I , dissolved oxygen and hydrostatic pressure. • SCC of TC4 is mainly TG, mixed with IG especially on phase boundaries.