Phase-field approach to polycrystalline solidification including heterogeneous and homogeneous nucleation

TL;DR

This paper advances phase-field modeling of polycrystalline solidification by incorporating nucleation mechanisms, boundary conditions for contact angles, and crystallographic orientations, validated through comparisons with atomistic simulations and diverse crystal morphologies.

Contribution

It introduces a comprehensive phase-field framework that includes heterogeneous and homogeneous nucleation, orientation modeling, and complex morphologies for polycrystalline solidification.

Findings

Agreement with atomistic simulations for nucleation barriers

Successful modeling of diverse crystal morphologies

Illustrative dendritic solidification results

Abstract

Advanced phase-field techniques have been applied to address various aspects of polycrystalline solidification including different modes of crystal nucleation. The height of the nucleation barrier has been determined by solving the appropriate Euler-Lagrange equations. The examples shown include the comparison of various models of homogeneous crystal nucleation with atomistic simulations for the single component hard-sphere fluid. Extending previous work for pure systems (Granasy L, Pusztai T, Saylor D and Warren J A 2007 Phys. Rev. Lett. 98 art no 035703), heterogeneous nucleation in unary and binary systems is described via introducing boundary conditions that realize the desired contact angle. A quaternion representation of crystallographic orientation of the individual particles (outlined in Pusztai T, Bortel G and Granasy L 2005 Europhys. Lett. 71 131) has been applied for modeling a broad variety of polycrystalline structures including crystal sheaves, spherulites and those built of crystals with dendritic, cubic, rhombododecahedral, truncated octahedral growth morphologies. Finally, we present illustrative results for dendritic polycrystal-line solidification obtained using an atomistic phase-field model.