Fig. 1 a XRD patterns of the HEA samples fatigued under different strain amplitudes at 500 °C; b EBSD inverse pole figure (IPF) maps; c EBSD phase maps and the corresponding zoom-in images are marked as I, II and III. Red and green represent the FCC matrix and the second phase, respectively. (b1, c1) Undeformed sample; (b2, c2) 0.2% sample; (b3, c3) 0.5% sample

Fig. 2 Bright-field (BF)-TEM images of 0.2% a, b and 0.5% c, d samples

Fig. 3 a BF-TEM image showing the distribution of precipitates in 0.2% sample; b HAADF image and the corresponding element maps of Cr, Mn, Fe, Co, and Ni; c, d SAED patterns taken along [$\stackrel{\mathrm{-}}{1}$ 0 $\stackrel{\mathrm{-}}{1}$] zone axis and [02 $\stackrel{\mathrm{-}}{1}$] zone axis from I and II in a, respectively

Fig. 4 a BF-TEM image showing the distribution of precipitates in 0.5% sample; b HAADF image and the corresponding element maps of Cr, Mn, Fe, Co, and Ni; c, d SAED patterns taken along [010] zone axis and [$\stackrel{\mathrm{-}}{1}$ 01] zone axis from III and IV in a, respectively

Fig. 5 Potentiodynamic polarization curves of HEAs with different conditions in 3.5 wt% NaCl solution

Fig. 6 Corrosion morphologies of samples after polarization from − 0.5 VSCE to 0.2 VSCE: a undeformed sample; b 0.2% sample; c 0.5% sample

Fig. 7 a Nyquist and b Bode plots of HEAs with different conditions in 3.5 wt% NaCl solution. The point diagram represents the experimental data, and the line diagram represents the fitting curve of the equivalent circuit model

Fig. 8 Mott-Schottky curves of CrMnFeCoNi samples with different conditions in 3.5 wt% NaCl solution: a undeformed sample; b 0.2% sample; c 0.5% sample

Fig. 9 HAADF images of 0.2% sample before immersion a and after immersion b; c local zoom image from the white square regions in b and the corresponding element maps of Cr, Mn, Fe, Co, Ni, and O

Fig. 10 a HAADF image of 0.5% sample showing the corresponding GBs morphology after immersion; b local zoom image from the white square region in a and the corresponding element maps of Cr, Mn, Fe, Co, Ni, and O. White and orange arrows represent corrosion of NiMn phases and GBs, respectively

Fig. 11 a HAADF image of 0.5% sample showing the corresponding intragranular morphology after immersion; b local zoom image from the white square region in a and the corresponding element maps of Cr, Mn, Fe, Co, Ni, and O

Fig. 12 Schematic of the corrosion mechanism of the 0.2% and 0.5% samples