Self-diffusion in Zr-Cr and Zr-Fe alloys

Abstract

Self-diffusion studies in a series of zirconium-rich alloys containing 2.05, 3.49, 4.08 and 7.86 at%Cr and 0.98, 1.35, 1.64, 3.54 and 6.37 at.%Fe have been carried out in the temperature range 1173–1618 K, using standard serial-sectioning technique. The temperature dependence of self-diffusion coefficients in all these alloys could be described by Arrhenius expressions of the type D = D₀ exp (-Q/RT). The data have been analysed on the basis of current concepts of alloy diffusion. An analysis based on the vacancy mechanism leads to negative values of the correlation factors. The possibility of interstitial-vacancy pair and ω-phase embryos being rate-controlling mechanisms is also discussed.