Effect of cathodically charged hydrogen in titanium aluminides studied by microhardness profiling

The effect of cathodically charged hydrogen in Ti-24Al-20Nb and Ti-24Al-27Nb alloys was studied by microhardness profiling. The hardness of both the alloys increases with increasing hydrogen charging time. The hardness profiles obtained after hydrogen charging exhibit two distinct regions: a surface hardened layer and a central region showing a lower hardness than the surface. Evidences for interaction of hydrogen with the material was obtained by baking of the hydrogen charged specimens at 800°C and 400°C.