95Zr Diffusion along the Α/β Interphase Boundaries of a Zr-2.5Nb Alloy

A Zr-2.5Nb alloy was submitted to a heat treatment that resulted in a stabilized two-phase structure, resolvable by optical microscopy and with natural interphase boundaries. Diffusion of 95Zr was studied along the α/β interphase boundaries prepared in the range of temperature 922–1109 K, corresponding to the α+βZr field. The interphase boundary diffusion coefficients obtained were 3 to 4 orders of magnitude higher than bulk diffusion in the corresponding β phase and more than 6 orders with respect to the α phase. The Arrhenius plot shows a straight line that is represented by Pi = 1.5 × 10−4 exp(−306kJRT) (m3/s).