Figure 3

a) 3D visualization of a region of the crack front obtained by serial section FIB-SEM with the grain boundary (A) and CSL boundaries (B) indicated. b) EBSD map from final slice adjacent to the serial section FIB-SEM volume, showing crystal orientation Euler colours. (A) marks the grain boundary, (B) marks the CSL boundaries and (C) marks two examples of slip bands (referred to in main text). c) a high angle annular dark field (HAADF) image of the extracted slice, d) STEM-EDX image of the same slice showing a chemical map with a combination of Fe, Ni, Cr, Mo and Si. e) and f) high resolution elemental maps showing Cr distribution along and ahead of the corrosion front along e) the Σ11boundary and f) the slip band are indicated in d) by D1 and D2 respectively.