Tailoring microstructures of CoCrFeNiNb_0.25 hypoeutectic high-entropy alloy by hot deformation

CoCrFeNiNb_0.25 hypoeutectic high-entropy alloy (HEA) has shown good mechanical properties. However, due to interdendritic eutectics, it is challenging to further optimize the microstructure through cold rolling and annealing. The current study showed that hot deformation effectively tailored the hypoeutectic microstructure. We investigated the hot deformation behavior and microstructure evolution of the dual-phase CoCrFeNiNb_0.25 HEA at different temperatures from 800 to 1000 °C and different strain rates from 0.01 to 10.00 s⁻¹. The systematic investigation showed the deformation activation energy around 500 kJ·mol⁻¹. Microstructure with refined grains and uniformly distributed Laves phases can be obtained after 70% compression at 900 °C with a strain rate of 0.01 s⁻¹. Graphical abstract: [Figure not available: see fulltext.]