Fatigue behavior of additive manufactured CrFeCoNi medium-entropy alloy

•Machining process plays a notable role in the fatigue properties of the printed CrFeCoNi alloy.•Annealing decreases the yield strength of the printed CrFeCoNi alloy.•Heat treatment does not affect the fatigue life of printed CrFeCoNi alloy in the HCF regime.•Recrystallization process of the printed CrFeCoNi alloy occurs at 800°C.•Secondary phases are observed in the printed CrFeCoNi alloy after annealing at 800°C. [Display omitted] High-entropy alloys (HEAs) are considered to be prospective materials for operation in harsh environments. These materials often demonstrate high strength during static tests. However, a limited number of studies describe the fatigue properties of HEAs. Most of them focused on the two systems of CoCrFeMnNi or AlCoCrFeNi produced by arc or induction meltings. In this paper, the fatigue behavior of CrFeCoNi medium-entropy alloys (MEAs) produced by additive manufacturing was investigated to extend the understanding of the HEA applications. The fatigue test is conducted at a frequency of 25 Hz, and the stress ratio of 0.1. The changes in fatigue and tensile properties are studied through structural and phase analysis. Special emphasis was placed on evaluating the impact of machining and heat treatment on the fatigue characteristics of the MEA samples.