ISING-MODEL FOR PHASE-SEPARATION IN ALLOYS WITH ANISOTROPIC ELASTIC INTERACTION .2. A COMPUTER EXPERIMENT

When a metallic alloy is quenched into a miscibility gap, a mixture of two phases develops, whose domain structure then coarsens because of the interfacial energy between the two phases. This spatial arrangemen t of the domains and the rate at which they evolve may be strongly inf luenced by elastic interactions. In a recent paper, the authors descri bed a method for simulating the effect of anisotropic elastic interact ions in a two-dimensional Ising model of a cubic alloy, using Kawasaki dynamics with the elastic interactions represented by a long-range tw o-body interaction potential. Here we present the results of such simu lations at various temperatures, alloy compositions and misfits (by '' misfit'' we mean the difference in size between the two kinds of atom) , exhibiting snapshots both of the microscopic configurations (corresp onding to experimental measurements using transmission electron micros copy) and of their squared Fourier transforms (corresponding to measur ements using small-angle X-ray or neutron scattering). The anisotropy of the two-phase structure increased with time, misfit and composition but decreased with increasing temperature. The rate of coarsening of the domains was found, surprisingly, to be roughly independent of the misfit at a given value of temperature relative to the critical phase transformation temperature. Copyright (C) 1996 Acta Metallurgica Inc.