KINETICS OF STRESS-RELAXATION CAUSED BY THE COMBINATION OF INTERFACIAL SLIDING AND DIFFUSION - 2-DIMENSIONAL ANALYSIS

The kinetics of stress relaxation due to the combined action of slidin g and diffusion on the matrix-inclusion interface has been examined in a material containing inclusions. The interaction between the inclusi ons is taken into account by the average field method. The sliding rat e is connected to a tangential traction, and the normal displacement j ump rate due to the diffusion is written in terms of the distribution of a normal traction. These tractions are also determined by the amoun t of sliding and diffusion. The strain due to the relaxation consists of two parts, each having the form of a first-order reaction. The rela xation strength and time of both terms depend on the interfacial visco sity and diffusivity, i.e. the sliding and diffusion are coupled. This is because the sliding induces the normal traction and the diffusion the tangential traction. The Coble creep is examined as an extreme cas e of the inclusion volume fraction approaching unity. The role of boun dary sliding is emphasized in the Coble creep. (C) 1998 Acta Metallurg ica Inc.