First principles study on the elastic properties and electronic structures of (Fe, Cr)3C

First principles calculations are performed to investigate the elastic properties and electronic structures of Cr doped Fe3C carbides, the obtained results are compared with Cr3C and Fe3C. The calculated bulk modulus of Fe11CrC4 and Fe10Cr2C4 is 260GPa and 270GPa, respectively, larger than Fe3C. So the hardness of Fe3C phase can be enhanced by doped with an appropriate amount of Cr, however, the calculated formation enthalpy and defect formation enthalpy of Fe11CrC4 and Fe10Cr2C4 are positive. On the other hand, the electronic calculations reveal that the ground states of Fe11CrC4 and Fe10Cr2C4 are ferromagnetic. The evaluated local magnetic moments of Fe at 4c sites are larger than that of 8d sites, which is analogous to Fe3C. Milliken population results indicate that the stabilities of Fe11CrC4 and Fe10Cr2C4 are reduced mainly due to the strong repulsive bonds among metal atoms.