High-entropy FeNiCoCr alloys with improved mechanical and tribological properties by tailoring composition and controlling oxidation

•Composite FeNiCoCr HEAs are fully densified after spark plasma sintering.•The composite HEAs possess excellent comprehensive properties of mechanical strength, ductility and wear performances.•Second phase precipitation and grain refinement contribute to the strengthening.•No ceramic lubricants are added; thus, the composite alloys remain high ductility.•Cobalt oxides form at worn surface, leading to the formation of a glaze layer and self-lubrication.