Figure 1. Partial dislocation activity and stacking-fault formation.

(a,b) Bright-field TEM images that show the formation of SFs (indicated by the red arrows) at the crack tip (top left-hand corner) under in situ loading of the CrMnFeCoNi high-entropy alloy (scale bar, 50 nm). Beam direction is [110]. (c,d) High-resolution TEM images captured from the in situ high-resolution TEM movie (scale bar, 2 nm). The formation of multiple SFs at the crack tip (bottom left-hand corner) was observed at the atomic scale. (e) is the magnified inverse fast Fourier transform image showing the atomic structure and stacking sequence (marked in yellow) of the SFs, surrounded by the red box in Fig. 1d. (The rapid motion of the Shockley partial dislocations and corresponding formation of SFs near the crack tip can be seen in real time in Supplementary Movies 1 and 2).