A first-principles study of cementite (Fe₃C) and its alloyed counterparts: Structural properties, stability, and electronic structure

As a part of our systematic study, the total energies and equilibrium cohesive properties of carbides with the structure of cementite (Fe₃C), and its alloyed counterparts (Fe₂MC, FeM₂C and M₃C with M = Al, Co, Cr, Cu, Fe, Hf, Mn, Mo, Nb, Ni, Si, Ta, Ti, V, W and Zr) are calculated employing electronic density-functional theory (DFT), all-electron PAW pseudopotentials and the generalized gradient approximation for the exchange-correlation energy. In this study, following properties are calculated: (i) Unit cell-internal and external parameters of binary and ternary cementites, (ii) Equation of state (EOS) parameters defining a few material constants, (iii) Zero-temperature heat of formation of binary and ternary cementites, (iv) Ground-state structure of Mn₃C, and (v) Electronic structure and selected magnetic properties. The bonding between M and C in M₃C is discussed based on analyses of calculated density of states and charge densities.