Embedded atom calculations of unstable stacking fault energies and surface energies in intermetallics

We performed embedded atom method calculations of surface energies and unstable stacking fault energies for a series of intermetallics for which interatomic potentials of the embedded atom type have recently been developed. These results were analyzed and applied to the prediction of relative ductility of these materials using the various current theories. Series of alloys with the B2 ordered structure were studied, and the results were compared to those in pure body-centered cubic (bcc) Fe. Ordered compounds with L1(2) and L1(0) structures based on the face-centered cubic (fee) lattice were also studied. It was found that there is a correlation between the values of the antiphase boundary (APE) energies in B2 alloys and their unstable stacking fault energies. Materials with higher APE energies tend to have higher unstable stacking fault energies, leading to an increased tendency to brittle fracture.