Lattice Inversion Method Research Articles

Theoretical investigation on site preference of foreign atoms in rare-earth intermetallics

This paper adopts the lattice inversion method in acquiring the interatomic potentials related to rare-earth and transition metals and characterizes the site occupancies of Fe and Co in Y(Co,Fe) 5, Y 2(Co,Fe) 17, Y 3(Fe,Co,M) 29, and YTi(Fe,Co) 11 by combining these potentials with computer simulation. The results of this research are in good agreement with experimental data. The substitution behaviors and the energy variation introduced by alloying elements M (M=V, Mo, Cu, Ni) in YTi(Fe,M) 11 are also calculated. A special importance is laid on the statistical analysis of the structure of YTi(Fe,Co) 11. This research is the first to present the phonon density of states of 1:12 structures, and it also carries out a qualitative analysis featuring the coordination and the relevant potentials.

Application of a Simple Semi-empirical Interatomic Potential Model to Phonon Density of States of Fe3Al

We proposed a simple analytical interatomic potential model by extending the framework of embedded-atom model to include the non-central three-body potentials. This model can be easily applied to treat transition metals and their alloys based on the very recently developed lattice inversion method. We used the model to calculate the phonon density of states and entropy of Fe3Al, and the results were in agreement with the experimental data.

Atomistic analysis of the field-ion microscopy image ofFe3Al

A unified lattice inversion method is applied to calculation of interatomic potentials and binding-energy differences between various kinds of surface atoms. Based on these calculated interatomic potentials, the field-ion microscopy images for Fe3Al are discussed in detail in order to develop the general concept and the evaluation method of selective evaporation for binary ordered alloys. @S0163-1829~98!01022-4#

Interatomic potentials between distinct atoms from first-principles calculation and lattice-inversion method

The effective interatomic potentials between distinct atoms in intermetallics, such as FeAl, Fe3Al, NiAl, Ni3Al, FeCr, Al3Cr, AlLi, Al3Li, and AlLi3, are obtained by inversion of first-principles cohesive energy curves based on the lattice inversion method of Chen. The obtained potentials are used to evaluate the phonon dispersions and linear thermal expansion of some intermetallic compounds, as well as the site preference of alloying element Cr in the D03-ordered Fe3Al.

Structure Properties of Ternary Hydrides Ni3AlHx

The structure properties of the ternary hydrides Ni3AlHx are studied by use of the interatomic pair potentials obtained from the first principles electronic structure calculation and Chen-Mobius 3-dimensional lattice inversion method. The heat of formation and volume expansion of the hydrogenized systems are investigated.

Inverse Lattice Problem and Finnis-Sinclair Model

The lattice inversion method is used to construct the pair potential and the hopping integral in Finnis-Sinclair model. In the approach, the lattice sum of square hopping integral is assumed to be an exponential function versus the nearest-neighbour distance, with two parameters determined from the Cauchy discrepancy and the difference of the unrelaxed vacancy-formation energy with the sublimation energy. The individual hopping integral is inverted from the exponential function and the pair potential is inverted from the remaining part of total cohesive energy.

Lattice Inversion Method and ab initio Pair Potentials in Cu-Ag, Cu-Au and Ag-Au Intermetallic Compounds

The lattice inversion method is used to construct ab initio pair potentials in the noble-metal alloy systems Cu-Ag, Cu-Au and Ag-Au from the elemental crystals and a L12 binary superstructure as references. Also, we present an alternative method for the determination of the three-dimensional Möbius functions by using the Kronecker expansion.

A lattice inversion method to construct the alloy pair potential for the embedded-atom method

The lattice inversion method is used to construct the pair potential between a pair of unlike atoms for Cu-Au and Cu-Pd intermetallic compounds within the framework of Johnson's analytical model of the embedded-atom method. Compared with previous treatises, the alloy potential obtained by the present method is based on the Ll2 superstructures Cu3Au and Cu3Pd as references so that the usual assumption that the pair potential between distinct atoms is a function of monatomic pair potentials is cancelled. The alloy potentials from inversion fall in with those from the average schemes of Foiles el al. and Johnson in the short range but show deviation in the long range. The present method is used to solve the considerable disagreements of Johnson's calculations for the dilute-limit heats of solution and the phase stabilities of the intermetallic compounds of palladium with noble metals. While the overall degree of agreement is substantially improved, it is not good in some cases, nor is the phonon spectrum of gold.

Application of Lattice Inversion Method to Embedded‐Atom Method

AbstractA model for the embedded‐atom method with the use of the lattice inversion method is presented. The lattice sums of electron density and pair potential are assumed to be exponential functions of the lattice parameter. The individual functions of potential and density are inverted from the corresponding lattice sums by using the lattice inversion method. The model parameters are explicitly written by five physical inputs, i.e. the equilibrium lattice constant, the bulk modulus, the Voigt average shear modulus, the sublimation energy, and the unrelaxed vacancy‐formation energy. As applications, the 〈100〉 uniaxial stress strain curves in the absence of lateral contraction and shear‐mode failure for Cu, Ag, Au, Ni, Pd, and Pt are calculated. The predictions of tensile strengths and failure strains by the present method are found smaller than those by the pair‐potential model. The results are in agreement with first‐principles calculation of Esposito et al. for Cu and with empirical calculations of Milstein for Ni.

An analysis of MIL-STD-471 test methods : David A. Heiser. Proc. Annual Reliability and Maintainability Symposium, San Francisco, p. 43 (22–24 January 1980)

Experimental determination of the cobalt solubility in the three-phase triangle face-centered cubic + Cr7C3 + graphite have been carried out. In the present work these results are compared with atomistic calculations of the solubility of Co in Cr7C3 phase based on ab initio cohesive energies and lattice inversion method. Comparisons are also made with the literature data reported earlier [Köster W, Sperner F. Arch Eisenhuttenwesen 1955;26:555; Thompson ER, Lemkey FD, Metall Trans 1970;1:2799; Sahm PR, Watts DJ. Metall Trans 1971;2:1260; Sahm PR, Lorenz M, Hugi W, Fruhauf V. Mettal Trans 1972;3:1022; Tuma H, Löbl K. Kovove Mater 1971;9:221; Fritscher K. Thermochim Acta 1979;29:357].