It was recalled that discontinuous coarsening could follow discontinuous precipitation at either the same temperature, or at another temperature. The latter case was studied here, at temperatures ranging from 353 to 513K, after discontinuous precipitation (393K, 60h). A detailed kinetic analysis of the process, which was performed using the Livingston-Cahn model, led to an under-estimation (30.7kJ/mol) of the activation energy for the grain boundary chemical diffusion of Ag. The value (67.0kJ/mol) which was deduced by using the modified Petermann-Hornbogen model compared well with the grain boundary self-diffusion of Zn. It was concluded that the above coarsening process was boundary diffusion-controlled.

I.Manna, J.N.Jha, S.K.Pabi: Journal of Materials Science, 1996, 31[9], 2401-7