Notch shape dependence of fatigue crack extension in equiatomic CrMnFeCoNi high-entropy alloy

•Fatigue tests on high-entropy alloy with three different micro-stress concentration sources.•Fatigue crack behavior, fractographic analysis, a fatigue crack shape analysis and strain analysis.•FIB-notch with a length of 100 µm and depth of 50 µm could not influence.•Plastic deformation-mode fatigue crack growth and damage accumulation-mode fatigue crack propagation.•Fatigue crack extension mode was transited by the severity of the strain concentration source. Fatigue tests were conducted on an equiatomic CrMnFeCoNi high-entropy alloy with three different micro-stress concentration sources. A fatigue crack behavior analysis using a replica of a specimen surface, fractographic analysis in a fracture surface, fatigue crack shape analysis, and strain analysis under the fracture surface were performed. It was found that the fatigue crack extension mode was transited by the severity of the strain concentration from the damage accumulation mode to the plastic deformation mode.