First-principles study of the interaction of solutes with Σ3(11-1) symmetric tilt grain boundaries in α-Fe

The structural, cohesive and magnetic properties of a symmetric grain boundary of tilt Σ3(70.53)[011](11-1) in pure bcc iron and with commonly used alloying elements (Si, Co, Mn, Ti, Cu, Mo, Nb, V, Cr and Ni) by means of density functional theory calculations are studied. Solubility and segregation energies were calculated for different positions of dissolved atoms. Calculations show a tendency for impurities to segregate near the boundary. It was found that the substituting Co, Cu and Ni in the layer adjacent to the boundary have an embrittling effect, while other atoms enhance the cohesion of the grains. Magnetic moments on GB atoms are significantly higher than those on bulk atoms.