Atomistic investigation into the atomic structure and energetics of the ferrite-cementite interface: The Bagaryatskii orientation

Abstract

Atomistic modeling was used to investigate the energetics and structure of the Bagaryatskii orientation relationship between ferrite and cementite within pearlite. The atomic level results show that the interface structure consists of a rectangular array of dislocations that lie along the high symmetry directions of the interface. The interface can be constructed using three different atomic terminating planes in the cementite structure, which dictates the chemistry and registry of the interface and controls the interfacial energy. The FeC-Fe terminating plane is always the lowest energy because the interfacial dislocations are most easily able to spread on these planes, thus reducing the interfacial energy. These atomistic results compare favorably with results from a continuum model based on O-lattice theory and anisotropic continuum theory. The dislocation spacing and interfacial energies predicted from the continuum level agree well with the atomistic simulation results.