Effects of doping on anti-phase boundaries and the magnetic properties of the D03 structure in high silicon steel: first-principles insights

Abstract

The D0₃ ordered structure is crucial for the room-temperature plasticity of high silicon steel. The formation of anti-phase boundaries (APBs) due to dislocation movement in the ordered structures hinders subsequent dislocation motion, leading to embrittlement. A low anti-phase boundary energy (γ_APB) can facilitate dislocation slip and enhance the plastic deformation capability of the ordered structures. In this study, we calculated γ_APB of two types of APBs of D0₃ (110) 〈111〉 by substituting Fe atoms with six transition metals: Ti, V, Cr, Zr, Nb, and Mo. We also evaluated the mechanical constants and magnetic moments of the doped D0₃ structures. The results show that doping Cr, Nb, and Mo significantly reduces γ_APB, positively affecting the plasticity of D0₃. Charge density analysis indicates that Cr, Nb, and Mo, particularly Cr and Mo, increase charge transfer between atoms across the APBs, enhancing interatomic interactions. This gives a new theoretical explanation for the experimental findings that Cr and Nb can improve the plasticity of high silicon steel. Additionally, alloying elements influence the total magnetic moment of D0₃ compounds by altering the local environment of Fe atoms closest to Si, interatomic interactions, and the unpaired electrons in the d-band of the compounds.