Non-empirical study of the sliding process in the R 3 (111) grain boundary in tungsten Simon Dorfman a, * , David Fuks b , Luiz A.C. Malbouisson c , Kleber C. Mundim d a Department of Physics, Technion––Israel Institute of Technology, 32000 Haifa, Israel b Department of Materials Engineering, Ben-Gurion University of the Negev, P.O. Box 653, Beer-Sheva, Israel c Institute of Physics, Federal University of Bahia, Salvador, Ba, Brazil d Instituto de Quimica, Universidade de Brasilia, Caixa Postal 4478, 70919-970 Brasilia, Brazil Abstract We performed non-empirical simulations of the properties of the tungsten R 3 (111) grain boundary (GB) with boron atom and demonstrated the influence of many-body interactions on the resistance of the GB with respect to sliding. We also studied the propagation of relaxation in the vicinity of the GB. The many-body interatomic potentials used in these simulations were obtained from ab initio total energy calculations with the use of the recursion procedure. At each step of the slip process the equilibrium positions of the atoms nearby GB were calculated with the generalized simulated annealing technique. The relaxation of atoms in different planes was calculated. It was shown how the slip shifts in- fluence the penetration of the elastic field inside the grain. Ó 2002 Elsevier Science B.V. All rights reserved. 1. Introduction The contribution of a sliding of grain bound- aries (GBs) is estimated to be more than 60% in the case of the micrograin superplastic deformation [1,2]. It is the absolutely inhomogeneous part of the deformation, which localizes in a limited zone near the GB and strongly depends on crystallo- graphic structure of GB. Because of the experi- mental difficulties in measuring the energy characteristics of the GB sliding, much effort was applied to calculate them theoretically. These cal- culations are atomistic studies of interfaces with a wide range of interatomic potentials (IP) (includ- ing central-force many-body potentials of the embedded atom type) [3–7] or the same with ac- counting for non-central forces (NF). IPs usually comprise several parameters that are fitted to a number of experimental data such as atomic vol- umes, cohesive energies of the bulk structures, elastic modules, etc. In the case when IP with NF are applied for calculations the more precise con- figuration of electron energy bands is accounted in tight-binding approximation with an inclusion of higher than second (i.e., third and/or fourth) mo- ments of the electron spectra. In Ref. [8] it was Computational Materials Science 27 (2003) 199–203 www.elsevier.com/locate/commatsci * Corresponding author. Fax: +972-4-221514. E-mail address: phr24ds@techunix.technion.ac.il (S. Dorf- man). 0927-0256/03/$ - see front matter Ó 2002 Elsevier Science B.V. All rights reserved. doi:10.1016/S0927-0256(02)00446-9