The peculiarities and mechanisms of oxygen diffusion in zirconium

Data from the most reliable authors and literature relating to oxygen diffusion in alpha- and beta-Zr for a wide temperature range of 673 to 1473 K have been compiled and analysed. For the whole range of temperatures the non-linear temperature dependencies of oxygen diffusion coefficients in alpha- and beta-Zr have been obtained in different forms. The curvature of the Arrhenius plot has been explained by a change in the oxygen diffusion mechanisms being analysed within the framework of the compensation effect model in which two different mechanisms occur below and above 923 K in the temperature range covered. The weak temperature dependence of the oxygen diffusion anisotropy coefficients has been calculated in the terms of the modified atomic jumping model of the type O - O and O - T - O jumps for temperatures below and above 923 K respectively which can be presented as D-A = D-parallel to/D-perpendicular to =(1,04 +/- 0,01) exp(0,010 +/- 0,001 eV/kT) The obtained con-elation is in agreement with the estimations by the size model of impurity diffusion anisotropy. The effect of oxygen diffusion anisotropy and oxygen contents in the diffusion zone on the self-diffusion anisotropy in alpha-Zr is discussed.