Interdiffusion in binary beta-titanium alloys

Interdiffusion experiments were carried out on beta-Ti(Cr), beta-Ti(Mo), and beta-Ti(V) single-phase diffusion couples in the concentration range from 5at% to 15 at% for Cr, Mo, and V, respectively. The concentration distribution after diffusion annealing was measured with an electron probe microanalyzer. Interdiffusivities, (D) over tilde, were determined by the Boltzmann-Matano method. For Ti(Cr) and Ti(V) alloys no concentration dependence of (D) over tilde was found. The temperature dependence (D) over tilde(T) follows the Arrhenius equation for Ti(Cr) (1171K< T <1572K) and for TI(V) (1168K< T <1409K). In the case of Ti(Mo) the interdiffusivity is concentration dependent and decreases with increasing Mo content. The Arrhenius plot for Ti(Mo) shows an upward curvature at lower temperatures near the alpha/beta transition. The relative magnitudes of the interdiffusivities are (D) over tilde(Ti(Mo)) < (D) over tilde(Ti(V)) < (D) over tilde(Ti(Cr)).