# Competitive B2 and B33 Nucleation during Solidification of Ni50Zr50 Alloy: Molecular Dynamics Simulation and Classical Nucleation Theory

## TL;DR

This study uses molecular dynamics and classical nucleation theory to analyze the competition between B2 and B33 phases during Ni50Zr50 alloy solidification, revealing temperature-dependent nucleation behaviors and interface properties.

## Contribution

It provides a comparative analysis of B2 and B33 nucleation, highlighting differences in interface free energy behavior near melting temperature using simulation and theoretical methods.

## Key findings

- B2 and B33 phases are competitive at high supercoolings.
- SLI free energy for B2 matches capillarity fluctuation method extrapolation.
- B33 phase shows large anisotropy in SLI properties near melting temperature.

## Abstract

We investigated the homogenous nucleation of the stoichiometric B2 and B33 phases in the Ni50Zr50 alloy using the persistent embryo method and the classical nucleation theory. The two phases become very close competitors at large supercoolings, which is consistent with the experimental observations. In the case of the B2 phase, the linear temperature dependence of the solid-liquid interface (SLI) free energy extrapolated to the melting temperature leads to the same value as the one obtained from the capillarity fluctuation method (CFM). In the case of the B33 phases, the SLI free energy is also a linear function of temperature at large supercoolings but the extrapolation to the melting temperature leads to a value which is considerably different from the CFM value. This is consistent with the large anisotropy of the SLI properties of the B33 phase nearby the melting temperature observed in the simulation of the nominally flat interface migration.