Fig. 1: Comparison of dislocation lines in the Cantor alloy during in situ TEM straining and atomistic simulations of comparable size.

a Series of TEM snapshots showing a sequence of gliding Shockley partial dislocations on a {111}<110> slip system activated under tensile load. The TEM bright-field image was obtained at two beam diffraction conditions with strong excitation of g₀₂₂ beam. The SF bound by a pair of leading and trailing partial dislocations is visible with dark contrast. Difference images in the bottom row were prepared by using two TEM frames captured at denoted time intervals. Only a portion of the dislocation lines, marked by the red and yellow arrows, move within the time span. b Dislocation line of the leading partial dislocation (marked by “D” in a) extracted from consecutive TEM images. The dislocation lines show jerky glide motion; the dislocations exhibit a meandering shape as some segments get pinned during glide. c–e Series of atomistic simulation results showing the strong pinning of dislocations (red) during glide in the equimolar Cantor alloy at cryogenic (5 K) and ambient (300 K) temperatures and the weak pinning of dislocations in CoNi alloy at 300 K. Simulation cells with the length scale (101 × 152 × 75 nm³) comparable to the experimental conditions are used. Each sample contains a notch aligned with the shaded {111} glide plane from which dislocations nucleate during uniaxial straining. For each sample, dislocations are traced at three strain (ε) levels. Dislocations in the Cantor alloy show a similar meandering shape and strong localized pinning leading to wavy dislocations as in the experiments whereas dislocations in CoNi alloy show weak pinning, where the dislocation lines remain almost ideally straight.