Fatigue Crack Growth Behavior of the Quaternary 3d Transition Metal High Entropy Alloy CoCrFeNi

Abstract

Abstract CoCrFeNi, a 3d transition metal high entropy alloy, has shown promising mechanical and corrosion resistance properties. CoCrFeNi was subjected to tension-tension fatigue at room temperature and the steady-state fatigue crack growth characteristics and underlying deformation mechanisms were investigated. CoCrFeNi exhibited good steady-state fatigue crack growth resistance with the Paris law exponent at the lower end of the ductile metals range, m ≈ 2.5, regardless of load ratio. TEM analysis performed at different locations revealed that the plastic deformation mechanism changed from dislocation slip to the addition of nano-twinning as ΔK increased over crack life.