Fig. 6: Ex situ FIB milling showing subsurface IGSCC.

(a)–(d) show secondary electron images collected as a part of a series of FIB slices into the area ahead of a crack tip, in the same region as that analysed by APT (a–c) scale bars: 50 µm, (d) scale bar: 10 µm). All images were collected at a tilt of 52° relative to the electron beam. Additional secondary electron images showing intermediate FIB cuts are given in Supplementary Fig. 7.