Effect of plastic deformation on the kinetics of the solid state reaction between Cu and Zn

The kinetics of the solid-state reaction at the interface of a: Cu-Zn bulk diffusion couple subjected to compressive plastic deformation has been studied as a function of plastic strain, strain rate, and temperature. The experimental data have been interpreted on the basis of classical atomic transport theory, considering also the effect of plastic deformation on the growth rate of the reaction product. The diffusion coefficient at 150 degrees C (larger than the purely thermal value at the same temperature by about four orders of magnitude) is almost independent of temperature and is linearly dependent on the strain rate at which the deformation occurs. The only parameter controlling the thickness of the reacted layer appears to be the total strain experienced by the diffusion couple. These features of plastically enhanced diffusivity are coherent with a simple model of the behavior of the excess point defects created by plastic deformation, similar to that developed in order to describe radiation-enhanced diffusion. [S0163-1829(99)04417-3].