Effect of hydrogenation on microstructure evolution, mechanical and electrochemical properties of pure titanium

Abstract

Titanium possesses a wide prospect due to its attractive combination of mechanical and electrochemical properties, however, the large affinity of hydrogen during industrial application will reduce its service life. Nevertheless, few studies focus on the effect of hydrogenation on microstructure evolution, electrochemical property and deformation behavior of titanium at room temperature. In this work, these effects induced by additional hydrogen were investigated in detail. The results suggest that the additive hydrogen will reduce the grain size, leading to the formation of lamellar or needle structure alpha phase with an increasing volume fraction of titanium hydride. In the meantime, the mechanical properties and corrosion resistances of hydrogenated titanium increase first and then decrease with the increase of hydrogen content. The improvement of mechanical property can be attributed to the occurrence of deformation twins, which will equivalently reduce the grain size, leads to the enhancement of ultimate compressive strength, work hardening rate and dislocation storage capability while the ability of dislocation annihilation diminished, thus results in higher work hardening rate and better compression ratio. Meanwhile, the electrochemical properties of hydrogenated samples enhanced with the increasing corrosion resistance of compact layer, yet, the film structure converts from compact to porous when additive hydrogen content reach to 27.01 at.%, which results in the deterioration of corrosion resistance. Therefore, the work of this research will give some suggestions for the application of titanium.