THE DRIVING FORCE FOR CHEMICALLY-INDUCED MIGRATION OF MOLTEN NI FILMS BETWEEN W-GRAINS

The analysis indicates that a large part of the total driving force for forming an equilibrium W-Ni alloy is dissipated by Ni diffusion into W solid to form a coherent layer of a nearly equilibrium composition. A small fraction due to strain energy is left to drive the boundary migration which occurs by solution and reprecipitation in liquid. This work also demonstrates that the driving force and kinetics of the chemically driven migration of liquid films between grains are amenable to theoretical analysis in terms of relatively simple models.