Author:

Keywords:

phase-field models, 3-D grain growth, grain size distribution, dihedral angle distribution, nonuniform grain boundary energy, Science & Technology, Technology, Materials Science, Multidisciplinary, Materials Science, Phase-field models, Grain size distribution, Dihedral angle distribution, Nonuniform grain boundary energy, COMPUTER-SIMULATION, MICROSTRUCTURAL EVOLUTION, ANISOTROPIC SYSTEMS, MODEL, MOBILITY, KINETICS, 0204 Condensed Matter Physics, 0205 Optical Physics, 0912 Materials Engineering, Materials, 4016 Materials engineering, 5104 Condensed matter physics

Abstract:

Large-scale phase-field simulations were performed of the evolution of grain structures with nonuniform grain boundary energy. A novel approach is proposed to determine the average grain boundary dihedral angles between the grain faces along triple and quadruple line junctions from 3-D voxel-based microstructures. We examine the effect of grain boundary energy nonuniformity on the distributions of the grain size, number of faces per grain, and dihedral angles between grain faces. We study the effect of the initial grain size distribution on the evolution toward steady state for both nonuniform and uniform boundary energy systems. The steady-state grain size and number of faces distributions remain unimodal under all conditions investigated, whereas the dihedral angle distribution is found to become multi-modal when the ratio R=σ_H⁄σ_L between high and low grain boundary energies lies in the range of 1.39 to 1.81. In addition, when R≈√2 a topological transition is observed from a structure with grain faces meeting at triple lines (which themselves terminate in quadruple points) toward one in which the grain faces meet primarily at quadruple line junctions (ending at compact regions of triple junctions or very short triple lines).