Scaling law for growth of misoriented equiaxed Al-Cu dendrites: A phase-field study with in situ experiment validation

Abstract

We consider the effect of a mutual misorientation between two interacting equiaxed dendrites in polycrystalline materials on the scaling law of growth from undercooled melt. This effect is investigated by three-dimensional quantitative phase-field simulations of Al-Cu alloy solidification in thin samples. It has been found that the equiaxed dendritic growth kinetics changes due to the reduced solute interaction when considering mutual grain misorientation, and both the characteristic growth rate and primary dendritic arm length can be approximately correlated linearly to the misorientation of two dendrites. The scaling law, which originally uses the solute composition and the distance between two nuclei as physical parameters to describe the dynamics of primary dendritic arms, is then adapted with consideration of the misorientation. Compared with the previous scaling law that only concerns face-to-face growth of two dendrites, the predictions of the newly proposed scaling law taking the grain orientation in account are in better agreement with the experimental data.