The application of the analytic embedded atom method to bcc metals and alloys

Johnson and Oh have recently developed Embedded Atom Method potentials for bcc metals (Na, Li, K, V, Nb, Ta, Mo, W, Fe). The predictive power of these potentials was first tested by calculating vacancy formation and migration energies. Due to the results of these calculations, some of the functions were slightly modified to improve their fit to vacancy properties. The modified potentials were then used to calculate phonon dispersion curves, surface relaxations, surface energies, and thermal expansion. In addition, Johnson's alloy model, which works well for fcc metals, was applied to the bcc metals to predict dilute heats of solution.

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End Processing of MAEAM Pair Potential for BCC Metals

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.424-425.568 ◽

2012 ◽

Vol 424-425 ◽

pp. 568-572

Author(s):

Hak Son Jin ◽

An Du

Keyword(s):

Phonon Dispersion ◽

Pair Potential ◽

Embedded Atom Method ◽

Model Calculations ◽

Phonon Dispersion Curves ◽

Bcc Metals ◽

Embedded Atom ◽

Body Potential ◽

Multi Body ◽

Potential Parameters

An end processing function of the pair-potential of modified analytical embedded atom method (MAEAM) was suggested for bcc metals. Through fitting the elastic constants, cohesive energy and an equilibrium condition of bcc metal crystals correctly, we changed the pair-potential parameters and the modification term parameter of the multi-body potential. The model calculations fully demonstrate the structure stabilities and the phonon dispersion curves of seven bcc transition metals: Cr, Fe, Mo, Nb, Ta, V and W.

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Stiffening and End Processing of MAEAM Pair Potential for FCC Metals

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.424-425.718 ◽

2012 ◽

Vol 424-425 ◽

pp. 718-722

Author(s):

Hak Son Jin ◽

An Du

Keyword(s):

Phonon Dispersion ◽

Pair Potential ◽

Embedded Atom Method ◽

Model Calculations ◽

Fcc Metals ◽

Embedded Atom ◽

Body Potential ◽

Multi Body ◽

Potential Parameters ◽

Fcc Metal

A stiffening function and a truncated function of the pair-potential of the modified analytical embedded atom method (MAEAM) were suggested for fcc metals. Through fitting the mono-vacancy migration energy, the elastic constants, the cohesive energy and an equilibrium condition of fcc metal crystals correctly, we determined the stiffening parameter and changed the pair-potential parameters and the modification term parameter of the multi-body potential for fcc metals: Ag, Al, Au, Cu, Ir, Ni, Pd, Pt, and Rh. The model calculations fully demonstrate the phonon dispersion curves and the unrelaxed mono-vacancy properties of the nine fcc metals.

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Calculation of Phonon Dispersion for 3d Transition Metals Cr and Fe by Modified Analytic Embedded Atom Method

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.411.532 ◽

2011 ◽

Vol 411 ◽

pp. 532-536

Author(s):

You Xie ◽

Jian Min Zhang

Keyword(s):

Experimental Data ◽

Transition Metals ◽

Phonon Frequency ◽

Phonon Dispersion ◽

Phonon Dispersion Curve ◽

Embedded Atom Method ◽

Body Centered Cubic ◽

Phonon Dispersion Curves ◽

Embedded Atom ◽

Good Agreement

The modified analytical embedded atom method is applied to calculate the phonon dispersion of body-centered cubic 3d transition metals Cr and Fe along five symmetry directions [q 0 0], [1 q q], [q q q], [q q 0] and [1/2 1/2 q]. Our results of phonon dispersion curves are in good agreement with the available experimental data. For the two transition metals Cr and Fe, along the same direction, a similar phonon dispersion curve is obtained in spite of the phonon frequency decreases for Cr and Fe due to the atom mass increases. There are no experimental results for comparison along the directions [1 q q] and [1/2 1/2 q], further experimental measurement are needed.

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Application of the embedded atom method to Ni3Al

Journal of Materials Research ◽

10.1557/jmr.1987.0005 ◽

1987 ◽

Vol 2 (1) ◽

pp. 5-15 ◽

Cited By ~ 321

Author(s):

S. M. Foiles ◽

M. S. Daw

Keyword(s):

Elastic Constants ◽

Formation Energy ◽

Antiphase Boundary ◽

Embedded Atom Method ◽

Surface Geometry ◽

Mixed Composition ◽

Surface Energies ◽

Embedded Atom ◽

And Migration ◽

Equilibrium Phases

The embedded atom method [M. S. Daw and M. I. Baskes, Phys. Rev. B 29, 6443 (1984) used to calculate phase stability, lattice vibrational frequencies, point defect properties, antiphase boundary energies, and surface energies and relaxations for Ni3Al. The empirical embedding functions and core-core repulsions used by this method are obtained. The equilibrium phases for the Ni-rich half of the composition range of Ni–Al are determined for 1000 K and compared with experiment. The elastic constants and vibrational modes of Ni3Al are calculated and the elastic constants are compared with experiment. The formation energy, formation volume, and migration energies of vacancies are computed, and it is found that the formation energy of vacancies on the Ni sublattice is less than that on the Al sublattice. The (100) antiphase boundary is shown to be significantly lower in energy than the (111) antiphase boundary. The surface energies and atomic relaxations of the low index faces are computed, and it is shown that for the (100) and (110) faces that the preferred surface geometry corresponds to the bulk lattice with the mixed composition plane exposed.

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