Three-dimensional analysis of ferrite allotrimorphs nucleated on grain boundary faces, edges and corners

The ferrite allotriomorphs nucleated on austenite grain boundary faces exhibit complex morphologies. Most of them are of oblate ellipsoids in shape and some of them are plate-like or pyramid-like. Ferrite allotriomorphs nucleated on austenite grain boundary edges take the form of triangular pyramids or triangular bi-pyramids. Ferrite allotriomorphs nucleated on austenite grain boundary corners are of irregular shapes.