Characterization of the misfit dislocations at the ferrite/cementite interface in pearlitic steel: An atomistic simulation study

The characteristics of the misfit dislocations at ferrite/cementite interfaces (FCIs) for various orientation relationships (ORs) have important implications for the mechanical behavior and the phase transformation of pearlitic steels; however, the detailed characteristics of these misfit dislocations have not been thoroughly elucidated to date. Using the extended atomically informed Frank–Bilby (xAIFB) method and atomistic simulation, we characterized the structures of misfit dislocations and calculated the interface energies of five ORs (Bagaryatsky, Isaichev, Pitsch–Petch, Near Bagaryatsky and Near Pitsch–Petch), respectively. Atomistic calculations of the interface energies of five ORs reveal that (1) the Isaichev OR has the lowest interface formation energy and (2) Near Bagaryatsky and Near Pitsch–Petch ORs are energetically more favorable than exact Bagaryatsky and Pitsch–Petch ORs in spite of small misorientation angle. The interface formation energy of each OR is qualitatively well explained by the structure and spacing of FCI dislocations, which demonstrate the importance of the characterization of misfit dislocations. [Display omitted] •An atomistic-to-continuum method is proposed to study the heterophase boundary.•The method is applied to investigate the ferrite/cementite interface in pearlitic steel.•Misfit dislocations and interface energies of five orientation relationships are analyzed.•Near BA, IS and Near PP ORs are energetically more favorable than BA and PP ORs.•The interface energies are explained by the characteristics of misfit dislocations.