Open AccessPhase-field modeling of free dendritic growth of magnesium based alloy
Author(s) -
Duan Pei-Pei,
Hui Xing,
Zhi Chen,
Guanhua Hao,
Bihan Wang,
Jin KeXin
Publication year - 2015
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.64.060201
Subject(s) - dendrite (mathematics) , materials science , anisotropy , phase (matter) , radius , thermodynamics , alloy , péclet number , coupling (piping) , coupling parameter , magnesium alloy , supersaturation , condensed matter physics , mechanics , physics , composite material , optics , geometry , mathematics , computer security , quantum mechanics , computer science
In this paper, the process of the free dendritic growth of Mg-0.5 wt.%Al alloy in the basal plane (0001) is simulated in two-dimensional system by using a quantitative phase-field model. A convergence study is carried out to choose the optimal coupling parameter λ and grid width Δx/W0 in simulation. Then we systematically discuss the effects of the anisotropic strength ε and the supersaturation Ω on dendritical tip growth velocity, radius, Péclet number, and stability parameter σ *. Results show that the stability parameter σ * defined by the theory of microscopic solvability is a function of the anisotropy strength ε, i.e., σ* ≅ ε1.81905, which is obviously closest to σ * (ε) ≅ ε 1.75 obtained from the analytical solution. Moreover, for Ω σ * is approximately a constant while it sharply and monotonically decreases with the augment of the value of ε for Ω > 0.6. This indicates that there is a transition from solute-controlled dendrite to kinetic dendrite as Ω increases. Furthermore, the transition of the growth pattern from the snow-like to the circle-like patterns occurs as Ω increases.