Effect of volume fractions on microstructure evolution in isotropic volume-conserved two-phase alloys: A phase-field study

A detailed investigation was carried out to study the effect of volume fraction on microstructure evolution in segregation-free isotropic volume-conserved two-phase alloys. Large scale two-dimensional (2D) and three-dimensional (3D) simulations were performed for 10/90, 30/70 and 50/50 alloys with a modified quantitative phase-field model. The grain growth in the two-phase alloys was consistent with volume-diffusion controlled growth with growth exponent m similar to 3. The kinetic coefficient, mean grain size, mean number of faces, grain size distribution (GSD), grain topology distribution (GTD) and grain size/topological class relation were all influenced by the volume fraction of the minor phase (alpha) in the two-phase alloys. In the 10/90 alloy, a bimodal distribution in the GSD and GTD for the 2D total grain structure was found. The timelines of evolution of major-phase grains in 3D simulations for all alloys were examined. 'Particle-like' grain migration of isolated a-phase grains was observed in the 2D simulations. The formation and evolution of non-constant curvatures on interphase boundaries in the isotropic volume-conserved two-phase alloys is discussed. The microstructure evolution in the volume-conserved two-phase alloys was compared with that in non-conserved two-phase alloys (m similar to 2). Simulation results are found to be in good agreement with a wide range of previous experimental and computer simulation results. (C) 2016 Elsevier B.V. All rights reserved.