Influence of hydrogenation on high-temperature corrosion fatigue of α-titanium alloys

Abstract

We investigate the influence of prehydrogenation from the gas phase on high-temperature (230–240°C) corrosion-fatigue strength of titanium PT-7M, PT-3V, and 27 alloys and of their welded joints in solutions of chlorides, alkalies, and in distilled water. A considerable decrease in fracture resistance of hydrogenated PT-7M alloy in chloride solutions is observed, although this alloy is not so sensitive to their action in its initial state. solutions of alkalies and distilled water show a stronger corroding action, and prehydrogenation increases their effect. Hydrogenation positively influences the corrosion-fatigue strength of 27 alloy while, for PT-3V alloy, it causes a decrease in fracture resistance under comparatively low loads and an increase under high ones. The presence of stress concentrators is a substantial factor in the negative influence of hydrogenation. Meanwhile, the presence of welded joints is a positive influencing factor for strength at moderate hydrogenation. The experimental results are analyzed from the point of view of possible mechanisms of the influence of corroding media and hydrogen on fracture of titanium alloys.