Stresses at Grain Boundaries During Chemical Diffusion: Thermodynamics and Kinetics

Published

October 16, 2008

Author(s)

C A. Handwerker, J Blendell, P W. Voorhees

Abstract

We have examined how the stress fields produced by interdiffusion in a binary solid-state diffusion couple change the thermodynamic boundary conditions and the kinetics of diffusion. Even in systems forming ideal solid solutions, the compositions at local equilibrium across the incoherent grain boundary formed by the two sides of a diffusion couple become discontinuous when the lattice parameter is a function of composition. Furthermore, the kinetics of diffusion are changed from the unstressed case by both the change in the equilibrium compositions across the grain boundary relative to the composition calculated in the absence of stress and an increase in the apparent diffusion coefficient. The magnitudes of the compositional discontinulty and the apparent diffusion geometry and the crystallographic orientations of the solids forming the diffusion couple but are independent of the sign of either the stress or the variation of the lattice parameter with composition. The mechanisms of stress relief, which can reduce these effects, are discussed. Calculations of the compositional discontinuity for interdiffusion in the Cu-Ni system are also presented.

Citation

Acta Materialia

Pub Type

Journals

Keywords

cooper-nickel interdiffusion, diffusion copies, interdiffusion, stresses during diffusion, thermodynamics of stressed solids, thin films

Citation

Handwerker, C. , Blendell, J. and Voorhees, P. (2008), Stresses at Grain Boundaries During Chemical Diffusion: Thermodynamics and Kinetics, Acta Materialia (Accessed October 15, 2024)