2006 年 46 巻 10 号 p. 1523-1531
An ab initio study was carried out on interface energies, misfit strain energies, and electron structures at coherent interfaces between bcc Fe and MCs (NaCl structure, M=V, Nb, Ta). The interface energies at relaxed interfaces Fe/VC, Fe/NbC, and Fe/TaC were −0.120, −0.169 and −0.158 J/m2, respectively. 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 carbide was closely related to changes of the bond energies between Fe, M and C atoms before and after formation of the interfaces Fe/MC. The misfit strain energies in Fe/VC, Fe/NbC, and Fe/TaC systems were 0.086, 0.891 and 0.827 eV per 16 atoms (Fe; 8 atoms and MC; 8 atoms), respectively. The misfit strain energy became larger when difference of lattice parameters between the bulk Fe and the bulk MCs increased.
