Ab initio calculation of interfacial energies between transition metal carbides and fcc iron

摘要

An ab initio study was carried out on coherent and semicoherent interfacial energies for fcc Fe/MCs (NaCl structure, M = Ti, Zr, Hf, V, Nb, Ta) systems. The group V transition metal carbides have lower coherent and semicoherent interfacial energies than group IV transition metal carbides. Also, the coherent interfacial energies for fcc Fe/MCs systems are lower than those for bcc Fe/MCs systems. The difference between semicoherent and coherent interfacial energy for fcc Fe/MC systems becomes largerasthe misfit increases. The semicoherent interfacial energies at relaxed interfaces Fe/TiC, Fe/ZrC, Fe/HfC, Fe/VC, Fe/NbC and Fe/TaC were 0.600 Jm~(-2), 0.661 Jm~(-2), 0.946 Jm ~(-2), -0.050 Jm~(-2), 0.320 Jm~(-2) and 0.380 Jm ~(-2), respectively. In order to maximize precipitation strengthening effect in austenitic steel, VC is the most favorable precipitate under consideration.