Global understanding of deformation behavior in CoCrFeMnNi high entropy alloy under high-strain torsion deformation at a wide range of elevated temperatures

A number of recent studies have investigated deformation behavior CoCrFeMnNi (Cantor) alloy at elevated temperatures by using plastic to relatively small strains such as tensile testing. Therefore, little has been known about the this typical FCC high-entropy (HEA) in case that material is subjected ultra-high various temperatures. In present study, equi-atomic HEA was successfully deformed over a wide range (von Mises equivalent (ε) 1∼5.5) torsion ranging from 25 °C 1100 °C. Deformation twinning extensively activated moderate high (ε ≥ 1) and even found 600 where not normally expected Cantor alloy. The showed outstanding deformability highest fracture reached 4.0∼5.5 low below 400 excellent attributed extensive twin activities including formation bundles thin nanotwins well microbands formation. However, localized shear promoted straining could negatively affect deformability. heavy led significant reduction grain sizes down 50 nm∼150 nm. sudden shortage ductility occurred intermediate temperatures, (1.2∼1.3) were realized °C∼700 embrittlement accompanied micro-voids boundaries intergranular fracture. susceptibility caused precipitation Cr-rich σ-phases boundaries. Dynamic recrystallization (DRX) matrix an accelerated softening above Nucleation growth DRX grains fundamentally different those conventional alloys. This study gives insight into microstructure evolution mechanical response under