Superior strength-ductility balance of an extremely low stacking fault energy (SFE) high-entropy alloy (HEA) processed by novel hybrid-rolling

Abstract

An extremely low SFE Co20Cr26Fe20Mn20Ni14 FCC HEA was processed by warm-rolling (WR) and a novel hybrid-rolling (HR) (cryo-rolling followed by warm-rolling). The HR material showed finer nanostructure and a larger fraction of Cr-rich precipitates due to the finer microstructure and greater driving force resulting from the prior cryo-rolling step. Annealing resulted in finer recrystallized FCC grain size (GS) and a significantly higher fraction of in-grain precipitate in the HR material. The finer GS and higher in-grain precipitate fraction in the annealed HR material resulted in remarkably high strength (∼1125 MPa) and elongation (∼20%). The results highlighted the significant potential of this novel processing route for tailoring microstructure and properties of HEAs.