Numerical analysis of phase decomposition in A-B binary alloys using Cahn-Hilliard equations

The analysis of phase decomposition was carried out using the nonlinear and linear Cahn-Hilliard equations in a hypothetical A-B alloy system with a miscibility gap. These equations were solved by the explicit finite difference method assuming a regular solution model. The supersaturated solid solution and decomposed phases were considered to have an fcc structure. Different aging temperatures and thermodynamic interaction parameters ΩA-B were used to simulate different alloy systems. The numerical simulation results showed that the growth kinetics of phase decomposition in the alloy with 30at.% A was slower than that of 50 at.% A. Additionally, the start time and modulation wavelength of phase decomposition are strongly affected by the thermodynamic interaction parameter ΩA-B value. The numerical simulation results showed that the growth kinetics of phase decomposition with the linear equation is slower than that with the nonlinear one.