Effects of Ce on DO3-Ordered Phase, Coincident Site Lattice Grain Boundary and Plastic Deformation of Fe-6.9 Wt.%Si Alloy

Fe-6.9 wt.%Si steel sheets with different Ce doping were prepared by warm rolling and annealing. Fe-6.9 wt.%Si alloys’ poor plasticity was mainly caused by the large amount of highly brittle DO3-ordered structure, and the significant improvement in their plastic deformation ability was found after adding rare earth Ce. The results reveal that the solid drag effect of Ce on the enhancement of dislocation slip reduces the difference of energy between antiphase boundaries and matrix and affects diffusion of Fe and Si atoms in DO3-ordered structure, hindering the nucleation and growth of DO3-ordered phases. λ-fiber textures are transformed into stable γ-fiber textures related to more frequency of ∑CSL boundaries because of an increment on Ce addition. The transgranular and intragranular cracks form in non-Ce-doped alloy with coarse DO3-ordered phases, and the ductile fracture zone characterized with some dimples occurs on the surface of 0.024 wt.% Ce-doped alloy, which indicates that the plastic deformation ability of Fe-6.9 wt.%Si alloy is significantly improved by rare earth Ce doping.