Dendrite growth simulation of Al-Zn alloys by the phase field method

Abstract

Dendrite growth of Al-Zn binary alloy in one directional solidification process was simulated using the phase field method. The development of Zn composition profile and phase field were calculated and the effects of temperature gradient G and growth velocity V on the morphology of crystal growth were investigated. The obtained results dynamically showed that the curvature radius of the tip of the primary dendrite arm, R, became small and the number of the arms per unit length increased (i.e. the spacing between the primary dendrite arms, λ1 decreased) with increasing growth velocity V. The quantitative relationship between λ1 and V and that between the spacing of the secondary dendrite arm λ2 and the solidification time t were determined as λ1 α V 0.5 and λ23 α t, respectively. It was found that the values of R and the exponent of V for R agree well with the dendrite growth theory.