An ab initio study of the energies of coherent interfaces formed between bcc iron and carbides or nitrides of transition metals

Abstract

An ab initio study was carried out on interface energies at coherent interfaces between bee Fe and MXs (NaCl structure, M = Ti, Zr, Hf, V, Nb, Ta, X=C, N). The interface energies have positive values for carbides and nitrides of group IVB metals (Ti, Zr, Ho, while they have negative values for carbides and nitrides of group V-B metals (V, Nb, Ta). Influence of bond energy was estimated using the discrete lattice plane/nearest neighbor broken bond (DLP/NNBB) model. It was found that the dependence of interface energy on the type of carbides and nitrides was closely related to changes of the bond energies between Fe, M and X(=C, N) atoms before and after formation of the interfaces Fe/MX.