The Kinetics of the Liquid Phase Nucleation in a Stretched FCC Crystal: A Molecular Dynamics Simulation

Journal Article · Sat Sep 15 04:00:00 EDT 2018 · Physics of the Solid State

DOI:https://doi.org/10.1134/S1063783418090032· OSTI ID:22771016

Tipeev, A. O. ^[1]

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1. Ural Branch of the Russian Academy of Science, Institute of Thermal Physics (Russian Federation)

The kinetics of a spontaneous formation of liquid phase in a stretched (superheated) Lennard-Jones fcc crystal is studied. Molecular dynamics experiments are used to determine the main parameters of the nucleation process: nucleation frequency J, diffusion coefficient of nuclei D{sub *}, nonequilibrium Zel’dovich factor Z, and critical nucleus size R{sub *}. The calculations are performed at negative pressures from the endpoint of the melting line and at positive pressures that are higher by a factor of eight than the critical pressure. The simulation results are compared to the classical homogeneous nucleation theory. It is found that the theory qualitatively correctly reproduces the dynamics of developing the process. The theory and the simulation demonstrate good quantitative agreement for the transition rate of the liquid phase nucleus through the critical size, but there is large difference in the numbers of critical nuclei in the unit volume of the metastable phase. In the case of significant superheatings and negative pressures, the contribution of the energy of elastic stresses to the moving force of the phase transformation is small and it can be neglected in a first approximation. The mismatch between the theory and the simulation results can be eliminated taking that the surface free energy of a curved “crystal–liquid droplet” interface is smaller than that of a plane interface by 30–35%.

• OSTI ID: 22771016
• Journal Information: Physics of the Solid State, Journal Name: Physics of the Solid State Journal Issue: 9 Vol. 60; ISSN 1063-7834
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
APPROXIMATIONS
COMPARATIVE EVALUATIONS
CRITICAL PRESSURE
CRITICAL SIZE
CRYSTALS
DIFFUSION
DROPLETS
FCC LATTICES
FREE ENERGY
INTERFACES
LIQUIDS
MELTING
MOLECULAR DYNAMICS METHOD
NUCLEATION
SIMULATION
STRESSES
SUPERHEATING
SURFACES