Multi-phase field simulation of competitive grain growth for directional solidification

Abstract

The multi-phase field model of grain competitive growth during directional solidification of alloy was established, solving multi-phase field models for thin interface layer thickness conditions, grain boundary evolution and grain elimination during the competitive growth of SCN-0.24wt% camphor model alloy bi-crystals were investigated, the effects of different crystal orientations and pulling velocities on grain boundary microstructure evolution were quantitatively analyzed. The results show that in the competitive growth of convergent bi-crystals, when favorably oriented dendrites are in the same direction as the heat flow and the pulling speed is too large, the orientation angle of the bi-crystal from small to large is the normal elimination phenomenon of the favorably oriented dendrite blocking the unfavorably oriented dendrite, and the grain boundary is along the growth direction of the favorably oriented dendrite, and when the pulling speed becomes small, the grain boundary shows the anomalous elimination phenomenon of the unfavorably oriented dendrite eliminating the favorably oriented dendrite. In the process of competitive growth of divergent bi-crystal, when the growth direction of favorably oriented dendrites is the same as the heat flow direction and the orientation angle of unfavorably oriented grains is small, the frequency of new spindles of favorably oriented grains is significantly higher than that of unfavorably oriented grains, and as the orientation angle of unfavorably oriented dendrites becomes larger, the unfavorably oriented grains are more likely to have stable secondary dendritic arms, which in turn develop new primary dendritic arms to occupy the liquid phase grain boundary space, but the grain boundary direction is still parallel to favorably oriented dendrites. In addition, the tertiary dendritic arms on the developed secondary dendritic arms may also be blocked by the surrounding lateral branches from further developing into nascent main axes, this blocking of the tertiary dendritic arms has a random nature, which can have an impact on the generation of nascent primary main axes in the grain boundaries.

Exploration of the coupled lattice Boltzmann model based on a multiphase field model: A study of the solid–liquid–gas interaction mechanism in the solidification process

“…Among them, the phase field method [5,7] (PFM) is a simulation method that describes the kinetic evolution process of the system based on thermodynamics, and it has many advantages over other methods, such as the ability to accurately simulate a variety of complex microstructures without having to track the complex solid-liquid interface. [8,9] In addition, multiphase flow systems play an important role in natural and industrial processes, and the lattice Boltzmann method [10] (LBM), as a mesoscopic simulation method between macroscopic continuum simulation and microscopic molecular dynamics simulation, has been developing rapidly in the field of computational fluid dynamics (CFD) and shows great potential. [11] Currently, many scholars have successfully simulated complex multiphase flow systems using LBM.…”

GPU parallel computation of dendrite growth competition in forced convection using the multi-phase-field-lattice Boltzmann model

“…[10] Numerous scholars have conducted more systematic studies on the process, mechanism, and control of the competitive growth of directionally solidified grains by means of phase field simulations. [11][12][13] In the above-mentioned studies, the elimination mechanisms in grain boundaries have been extensively described, whereas the influence of the presence of convection in grain boundaries on the evolution of bi-crystal competition has been neglected, and the dendrite morphology under pure diffusion conditions is somewhat different from the real situation when convection is present. In a recent study, Pavan et al [14] used a multi-phase field model to investigate the competition for the growth of columnar dendrites under melt convection conditions.…”

Parameter calculation and result storage for phase-field simulation in α-Mg dendrite growth of Mg-5-wt% Zn alloy

“…Nevertheless, compared with the above two steps, calculating parameters, and result storage and post-processing were often only briefly mentioned in most of published papers. [16][17][18] There have been almost no systematic studies for the latter two steps, which will limit the application of the phase-field method. Moreover, according to Tourret et al, [19] the energy function at the core of phase-field model depends on a large number of parameters that control different energy contributions, and quantitative predictions of microstructure evolution require careful identification of parameters.…”