EFFECT OF STRAIN ON COARSENING: EXPERIMENTAL STUDIES ON THE EFFECT OF COHERENCY STRAINS ON COARSENING KINETICS: CURRENT STATUS AND FUTURE OUTLOOK

The effect of coherency strains on the coarsening rate constant in Ostwald ripening is an area that is not well understood. We briefly review the extant experimental data on the effect of coherency strains on coarsening rates and explain the need to account for variations in coarsening rates due to composition and diffusivity effects before drawing any conclusions on the dependence of coarsening rates on the misfit parameter. Using the pre-existing theories for coarsening rates in multi-component systems, we suggest a simple method to account for the composition dependence of coarsening rates arising from factors unrelated to coherency strain effects. We then present some of the results from our on-going work in the Ni-Al-Si system and explain the relevance of this study to our understanding of coarsening in internally-stressed systems. We conclude the presentation with our views on the direction of future research in this aspect of coarsening.