查看文章

We developed a series of Co-rich Co_xCr₂₅(FeNi)_75−x (x = 35, 45, 55, 65) high entropy alloys with improved strength and/or ductility, derived from lowering the stacking fault energy (SFE) and reducing the fcc phase stability of the equiatomic CoCrFeNi alloy. Thermodynamics and ab initio calculations demonstrated that increasing Co while decreasing Fe and Ni concentrations lower the SFE and reduce the fcc phase stability. The Co₃₅Cr₂₅Fe₂₀Ni₂₀ and Co₄₅Cr₂₅Fe₁₅Ni₁₅ alloys with single fcc phase, exhibit superior tensile properties, contributing to the twinning and fcc → hcp martensitic transformation. The present study offers a guideline for designing high-performance high entropy alloys.