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Title: Kinetic phase field parameters for the Cu-Ni system derived from atomistic computations

Abstract

In the phase field model of binary solidification the mobility terms which appear in the governing rate equations can be estimated from the liquid diffusion coefficients of the pure elements and the velocity of the solid-liquid interface as a function of undercooling. Molecular dynamics simulations utilizing embedded atom potentials have been employed to compute the liquid diffusivities for pure Cu and Ni in the vicinity of their melting points. In both cases the diffusion coefficient is found to vary linearly with temperature and the results are in good agreement with experimental values which are available for Cu. The simulations were also employed to obtain the boundary velocities in three different low index growth directions. The results for Cu and Ni were found to be very similar, with the slope of the velocity-undercooling curve at small undercoolings varying in the range 45--18 cm/s/K. Anisotropy in the growth behavior was observed with V{sub 100} > V{sub 110} > V{sub 111}. The solid-liquid interface velocities were found to be a factor of 4--5 less than the theoretical upper limit derived previously.

Authors:
; ;  [1];  [2]
  1. Sandia National Labs., Livermore, CA (United States). Computational Materials Science Dept.
  2. Lawrence Livermore National Labs., CA (United States)
Publication Date:
Research Org.:
Sandia National Laboratory
Sponsoring Org.:
USDOE, Washington, DC (United States)
OSTI Identifier:
684378
DOE Contract Number:  
AC04-94AL85000
Resource Type:
Journal Article
Journal Name:
Acta Materialia
Additional Journal Information:
Journal Volume: 47; Journal Issue: 11; Other Information: PBD: 8 Sep 1999
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; SOLIDIFICATION; COPPER ALLOYS; NICKEL ALLOYS; LIQUID METALS; INTERFACES; SIMULATION; MOLECULAR DYNAMICS METHOD; KINETICS; MASS TRANSFER; DIFFUSION

Citation Formats

Hoyt, J.J., Asta, M., Foiles, S.M., and Sadigh, B. Kinetic phase field parameters for the Cu-Ni system derived from atomistic computations. United States: N. p., 1999. Web. doi:10.1016/S1359-6454(99)00189-5.
Hoyt, J.J., Asta, M., Foiles, S.M., & Sadigh, B. Kinetic phase field parameters for the Cu-Ni system derived from atomistic computations. United States. doi:10.1016/S1359-6454(99)00189-5.
Hoyt, J.J., Asta, M., Foiles, S.M., and Sadigh, B. Wed . "Kinetic phase field parameters for the Cu-Ni system derived from atomistic computations". United States. doi:10.1016/S1359-6454(99)00189-5.
@article{osti_684378,
title = {Kinetic phase field parameters for the Cu-Ni system derived from atomistic computations},
author = {Hoyt, J.J. and Asta, M. and Foiles, S.M. and Sadigh, B.},
abstractNote = {In the phase field model of binary solidification the mobility terms which appear in the governing rate equations can be estimated from the liquid diffusion coefficients of the pure elements and the velocity of the solid-liquid interface as a function of undercooling. Molecular dynamics simulations utilizing embedded atom potentials have been employed to compute the liquid diffusivities for pure Cu and Ni in the vicinity of their melting points. In both cases the diffusion coefficient is found to vary linearly with temperature and the results are in good agreement with experimental values which are available for Cu. The simulations were also employed to obtain the boundary velocities in three different low index growth directions. The results for Cu and Ni were found to be very similar, with the slope of the velocity-undercooling curve at small undercoolings varying in the range 45--18 cm/s/K. Anisotropy in the growth behavior was observed with V{sub 100} > V{sub 110} > V{sub 111}. The solid-liquid interface velocities were found to be a factor of 4--5 less than the theoretical upper limit derived previously.},
doi = {10.1016/S1359-6454(99)00189-5},
journal = {Acta Materialia},
number = 11,
volume = 47,
place = {United States},
year = {1999},
month = {9}
}