Analytic embedded-atom method (EAM) interatomic potentials for body-centered cubic (bcc) transition metals have been constructed. The total energy is regarded as consisting of a pair potential part, an embedding interaction part and a modification term. All these parts are analytic functions of the atomic separations only and are fitted to various bulk properties, such as cohesive energy, vacancy formation energy, lattice constant and elastic constants. The present potentials are shown to predict a more realistic pressure–volume relationship so that interactions at separations smaller than that of the first-nearest neighbors can be treated. Interstitial formation energies are calculated for various configurations, using quenched molecular dynamics. Vacancy, surface and phonon spectra have been also studied andsatisfactory agreement with available experimental data has been found.

Using molecular dynamics simulations with an analytical embedded-atom method (MAEAM) model, the diffusion behavior of helium atoms at two Σ=5 symmetric grain boundaries of Ni was investigated in the present paper. The simulations demonstrate that the interstitial helium atoms are stable at the grain boundaries. Helium atoms in Ni lattices could diffuse easily to the grain boundary and precipitate into a cluster, which confirmed the fact that helium atoms could nucleate and grow up into bubbles at the grain boundaries. The diffusion activation energy of interstitial helium atom at grain boundaries was also determined.

The thermodynamic data, such as the formation enthalpies of disordered solid solutions and intermetallic compounds, and the lattice parameters in the RE–Au (RE = Sc, Y, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er) systems are calculated with the modified analytical embedded atom method (EAM). This work has been undertaken to investigate systemically in RE–Au alloying energies, and to augment available calorimetric data for enthalpies of formation in support of the development of accurate multicomponent thermodynamics databases for these technologically interesting systems. The accuracy of our calculations is assessed through comparisons with the experimental measurements and the theoretical results from the first-principles VASP as well as Miedema’s theory. The composition dependence of the heats of formation for these 10 binary systems is similar, and there is a minimum at 50 at.% Au for REAu (CsCl-type) ordered phase. In all 10 binary systems, the calculated zero-temperature intermetallic formation energies generally agree well with the calorimetric data obtained by the direct reaction synthesis and/or VASP results except for REAu2 (MoSi2type) phase. For the intermetallic phase, the calculated EAM and VASP zero-temperature lattice parameters agree well with the experimental data at ambient temperature. The largest discrepancy between the EAM calculated lattice parameters and experimental data [K. Fitzner,W.G. Jung, O.J. Kleppa, Metall. Trans. A 22 (1991) 1103 [16]; K. Fitzner, O.J. Kleppa, Metall. Trans. A 24 (1993) 1827 [17]; K. Fitzner, O.J. Kleppa, Metall. Trans. A 25 (1994) 1495 [18]; R. Ferro, G. Borzone, N. Parodi, J. Alloys. Compd. 321 (2001) 248 [19]] is approximately 10-18% for some intermediate phases, such as REAu (CrB-type) and RE3Au4 (Pu3Pd4-type).

In the present paper, the size and temperature effects on lattice distortion of Ag and Pt nanoparticles have been investigated in terms of atomic mean bond length using the molecular dynamics simulations and the modified analytic embedded atom method. It is found that the lattice contraction ratio decreases linearly with the reciprocal of the particle size. The average value of lattice contraction over the whole system is larger than that of the experimental data, and the average value of lattice contraction in the inner core has a better agreement with the experiment results. This phenomenon is mainly resulted by inhomogeneous lattice distortion. The surface distortion and the size effect on the inner core distortion are remarkable. As the grain size increases to a certain degree, the inhomogeneous surface lattice distortion is mainly localized to the outer shell with a thickness of 2-3 lattice parameters.