Atomistic Studies of Interfacial Structure and Properties

Abstract

The computer simulation of the structure and fracture of interfaces on an atomic scale requires a computationally efficient prescription for the total energy that is reliable both for small deviations from the bulk as well as for the free surfaces produced during fracture. The recently developed Embedded Atom Method is such a method. It will be briefly described and compared to traditional pair interaction approaches. In particular, it will be shown that the many-body effects inherent in the Embedded Atom Method are essential to correctly describe the experimentally observed surface reconstructions of Au surfaces. The necessary first step in simulating the fracture of an interface, such as a grain boundary, is the determination of the initial or equilibrium atomic configuration of the interface. Equilibrium Monte Carlo simulations using the Embedded Atom Method can determine this structure. This approach will be outlined and various results for grain boundary structure in fcc metals will be presented. The atomic structure of symmetric tilt boundaries is found to be significantly different from that deduced from energy minimization techniques. In addition, the Monte Carlo technique allows for the determination of thermal effects such as the vibrational amplitudes at the interface and the thermal expansion of the interface.