SPINODAL DECOMPOSITION OF CUCO ALLOYS - A COMPUTER-SIMULATION AND SOME FIM RESULTS

Based on a FIM study of rapidly quenched Cu-50 at% Co alloys, a computer simulation of the spinodal decomposition of CuCo alloys is carried out applying a numerical version of the Fourier transformation approach of the nonlinear diffusion equation. A polynomial approach of the free energy function of CuCo solutions is obtained and is applied to the simulations. The simulations show three stages of the evolution of the composition profile: strong modulation of the wavelength in the early stage, growth of the amplitude in the intermediate stage, and regularization of the configuration and a small recovery effect of the wavelength in the late stage. The kinetics of spinodal decomposition for different compositions and at different temperatures is also studied in detail. The wavelength of the composition profile shows a weak dependence on the aging temperature, whereas the kinetics is rapidly accelerated as the temperature increases.