PHASE-FIELD MODELING OF MICROSTRUCTURE FORMATION OF POLYCRYSTALLINE MATERIALS IN VARIOUS COOLING CONDITIONS

摘要

This paper presents a discontinuous finite element computational framework for the numerical solution to the phase-field equations during the solidification of polycrystalline materials. An important feature of the discontinuous method is that the continuity across the elements within the calculation domain is only weakly enforced, rather than rigorously enforced as done in conventional finite element method. The mathematical formulation and computational implementation are briefly described. Numerical simulations are conducted to study the interactions between the grains and the nuclei that are initially located close to or away from the boundary of the bulk grain. The phase-field evolutions during solidification in various cooling conditions are presented. Results indicate the dependence of grain growth behavior and its interface morphology on the undercooling temperature suppressed to the liquid pool. And this dependence is not so much related to the distance between the grain and nuclei.