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Interatomic potentials for atomistic studies of defects in binary alloys

Journal Article · · Acta Metall.; (United States)
A description of interatomic forces in pure metals and disordered, substitional binary alloys systems is developed on an empirical basis. The description is formulated for use in atomistic studies of lattice defects. In both pure metals and alloys the total internal energy is expressed as the sum of two terms: a pair potential term and a term that depends only on the average density of the material. It is assumed that in pure metals all of the cohesive energy is provided by the second term. The empirical parameters employed in the construction of potentials for pure metals are the cohesive energy and elastic constants. For alloys the different atomic sizes and electronegativities of the alloying elements are taken into account, and the potentials are self-consistently adjusted to the enthalpy of mixing for correponding alloy concentrations. In addition all potentials are required to satisfy the equilibrium conditions governing mechanical stability of the corresponding crystal structures. Reasonable agreement is obtained between calculated dependences of elastic constants on alloy concentration and available experimental data. Several derived potentials for pure metals and alloys are presented, in particular those employed in a subsequent atomistic study of grain boundary segregation. The scheme can be used to construct approximate descriptions of atomic interactions in specific binary systems, or for the construction of model systems in which the required empirical data are taken as variables.
Research Organization:
Univ. of Pennsylvania, Philadelphia
DOE Contract Number:
AC02-79ER10429
OSTI ID:
6088034
Journal Information:
Acta Metall.; (United States), Journal Name: Acta Metall.; (United States) Vol. 30; ISSN AMETA
Country of Publication:
United States
Language:
English