Ab initio Computer Simulation of the Energy Parameters and the Magnetic Effects in Ternary Fe–X–C (X = Si, P, S, Cr, Mn) Systems

Resumo

The equilibrium structure and the properties of ternary Fe–X–C (X = Si, P, S, Cr, Mn) systems are studied by ab initio simulation using the WIEN2k software package. The calculations are performed by the full-potential linearized augmented plane wave method (FLAPW) with allowance for the generalized gradient approximation (PBE-GGA). These methods are most accurate in terms of the density functional theory. The magnetic structure of Fe–X–C alloys and the interaction between carbon and impurity atoms at various distances are analyzed. Repulsion is detected between impurity silicon, phosphorus, and chromium atoms and carbon atoms in all three coordination shells, which significantly increases the dissolution energies of these impurities. Analogous repulsion for the first two coordination shells is also observed for the interaction of sulfur and carbon atoms, and weak attraction between these atoms appears in the third coordination shell. The interaction of carbon with manganese is characterized by attraction in the first two coordination shells, and the dissolution energies of both manganese and carbon decrease.