fig3

Figure 3. (A) Dark-field TEM image of region shown in Figure 2D. (B-D) High-resolution HAADF-STEM images of Σ3 twin boundary from three different positions, b-d marked in (A). (E) High-resolution HAADF-STEM image from (A) showing a triple atomic layer of a coherent Σ3 boundary with ABA stacking sequence. The corresponding EDS maps indicate a homogenous distribution of the four principle elements, i.e., Fe, Mn, Co and Cr. (F) High-resolution HAADF-STEM image from (A) showing a double atomic layer of HCP ɛ phase with BA stacking sequence formed by gliding of a leading Shockley partial dislocation. The matrix, coherent Σ3 boundary, 9R structure and HCP ɛ phase are highlighted by yellow, red, orange, and blue, respectively, in all HAADF-STEM images. TEM: Transmission electron microscopy; HCP: hexagonal close-packed; HAADF: high-angle annular dark-field; STEM: scanning transmission electron microscopy; EDS: X-ray spectroscopy.