Fig. 1: Ex situ HS-AFM measurements of sensitisation and strain.

Images show 3D HS-AFM topographic maps of: a GBs and GB carbide precipitates within thermally sensitised AISI Type 304 stainless steel, and (b) slip bands in sensitised AISI Type 304 stainless steel across a GB. Also shown is: c an HS-AFM topographic map of slip bands in sensitised AISI Type 304 stainless steel across a GB (scale bar: 1 µm), and (d) a line profile along the line labelled A shown in (c) as a dark blue line, showing variation in height across dislocation steps. Height measurements have an error of ±15 pm. Additional topographic images showing measurements of strain are given in Supplementary Fig. 2.