Abnormal chemical composition fluctuations in multi-principal-element alloys induced by simple cyclic deformation

High entropy alloys exhibit excellent combination of mechanical properties because of the unique com-position fluctuations,termed as‘concentration wave’.The concentration wave was closely related to mul-tiple aspects,including the fluctuation of local strain energy,local atomic environment,electronegativity,etc.Here we report for the first time that the amplitude of the concentration wave can be mechani-cally tailored under cyclic deformation in a well-known Cantor alloy.Atomic-scale energy-dispersive X-ray spectroscopy(EDS)mapping reveals that cyclic deformation may dynamically induce the clustering of solute atoms with a size of 1-3 nm,thus resulting in a higher concentration wave amplitude.The con-centration wave promotes strong interactions between dislocations and local solute clusters.Aside from the typical Taylor strengthening contribution due to the presence of isolated dislocations,the strength enhancement from the mechanically induced composition fluctuations was quantified to be as high as∼70 MPa,about one-third of the yield strength of the alloy without pre-deformation.This opens up a novel strategy of designing high strength alloys by tailoring solute configurations.