DRIFT DIFFUSION IN GRAIN-BOUNDARIES UNDER THE INFLUENCE OF STRESS-FIELDS

The diffusive‐elastic coupling between a misfitting inhomogeneity in a grain boundary and the related stress field is analysed within a continuum approach. The scaling behaviour of the basic equations allows some general conclusions on the time dependence of various processes like the spreading of an inhomogeneity, the diffusional creep and the growth of grain‐boundary voids. The coupled Green's functions for the spreading of an inhomogeneity and the related stress field over an infinite plane grain boundary are derived. They show that in the early stage the width of such an inhomogeneity develops in time as t1/3 (grain‐boundary diffusion), in the late stage as t1/2 (volume diffusion). Possible applications to the quantitative treatment of creep and void growth are indicated. Copyright © 1979 WILEY‐VCH Verlag GmbH & Co. KGaA