THE EFFECT OF HYDROGEN ON THE DIFFUSION MOBILITY OF METAL ATOMS IN THE BETA-PHASE OF TITANIUM-ALLOYS

Experimental results have been reported dealing with the effect of hyd rogen on the critical cooling rates of various titanium alloys and the diffusion mobility of aluminum and vanadium in the beta-phase of tita nium. Hydrogen alloying of laboratory and commercial multicomponent Ti -base alloys reduces their critical cooling rates and hinders in the a ttainment of phase equilibrium on heat treatment. Aluminum and vanadiu m concentration profiles in a weld joint of VT6 and VT1-0 alloys have been measured, and the diffusion coefficients of the elements in the b eta-phase have been calculated An increase in hydrogen concentration f rom 0.02 to 1.2 wt.% reduces the vanadium and aluminum diffusion coeff icients in the beta-phase by 4 and 3 times, respectively, with the dec rease being the greatest for hydrogen concentration less then 0.3 wt.% .