Significant reduction in friction and wear of a high-entropy alloy via the formation of self-organized nanolayered structure

Abstract

Sliding wear-induced nanolayering and its positive impact on wear resistance have been observed in conventional binary alloys with a matrix of high stacking fault energy (SFE), but this concept has never been reported in high-entropy alloys (HEAs) with low SFE. Here, we design and fabricate a (CoCrFeNi)90Ag10 HEA, consisting of a face-center-cubic (fcc) CoCrFeNi HEA matrix with low SFE and uniformly dispersed Ag precipitates. In comparison with CoCrFeNi, a significant reduction in friction and wear was found in (CoCrFeNi)90Ag10 HEA through the spontaneous formation of nanolayered subsurface microstructure during wear. The finding suggests a novel approach for designing HEAs that can achieve low friction and wear.