AB-INITIO CALCULATION OF SOLUTE EFFECTS ON AUSTENITE GRAIN BOUNDARY PROPERTIES IN STEEL

摘要

Ab-initio density functional theory calculations have been performed to determine the effect of solutes including Cr, Ni, Mo, and Mn on the boundary energy for a variety of coincident site lattice grain boundaries of FCC iron (austenite). The boundaries investigated were of tilt character and both symmetric and asymmetric boundary planes were investigated. Boundary energies were determined for boundaries in pure Fe and for boundaries with single solute atoms at a variety of sites in each boundary. The results are compared to Arrhenius type equations developed from experimental work in the literature and used to hypothesize a mechanistic model for the effects of solutes on boundary mobility based upon the thermodynamic and kinetic effects of solutes at austenite grain boundaries. The predictive capabilities of atomic configurations and bond structures are evaluated and areas for future work are identified. This work provides a new framework for understanding the effects of solutes on atomic scale grain boundary energies and solute drag effects on boundaries.