Hydrogen and deuterium diffusion in vanadium alloys

Hydrogen and deuterium diffusion coefficients were measured^between 473 and 230 K in alloys of vanadium containing titanium or^niobium. Boltzmann-Matano techniques allowed the measurement^of the hydrogen concentration dependence of the diffusion^coefficient. In addition, one of these techniques permitted a^determination of the terminal hydrogen solid solubility which was^greatly increased by alloying. Both the hydrogen and deuterium^diffusion coefficients were found to decrease with hydrogen isotope^concentration in all alloys at all temperatures. The effect of niobium^additions was to markedly reduce the rate of hydrogen migration to^a minimum in the 75 at. pct. Nb alloy. The rate of hydrogen migration^decreased with titanium concentration up to 30 at. pct. Ti, the^highest concentration examined in that alloy system. The diffusion^coefficients exhibited an Arrhenius temperature dependence and the^resulting diffusion activation energy and D(,o) values both increased^with titanium and with niobium concentration to a maximum of 75 at.^pct. Nb. Deuterium diffusion activation energies were larger than^corresponding hydrogen values in all alloys. The diffusion behavior^found in these alloys is not well represented by current local deep;trapping models;(\u271)DOE Reports IS-T-1000. This work was performed under ContractW-7405-Eng-82 with the Department of Energy