Atomic-scale evidence of chemical short-range order in CrCoNi medium-entropy alloy

High (or medium)-entropy alloys (H/MEAs) are complex concentrated solid solutions that may develop chemical short-range order (CSRO). In this regard, CrCoNi, the prototypical face-centered-cubic MEA, has recently kindled a debate in H/MEA community, as it is uncertain if CSRO can possibly form such multi-principal-element solution, where no equilibrium or metastable intermetallic compounds have ever been seen predicted. To answer challenging question, here we present firm experimental evidence for from electron diffraction well atomic-resolution mapping, under an appropriate zone axis. We also methodology to reliably determine locations of atomic columns line scan profiles maps, quantitative covariance-based correlation analysis column compositions reveal spatial correlations between various pairs. The detailed information affirms tendency like-pair avoidance and unlike-pair preference, specifies preferred packing plane stacking by three constituent species, suggests proposed configuration constitutes motif. fraction regions moderately lowered after either plastic deformation high-temperature heating. A comparison made with previous attempts identify CSROs H/MEAs.