Microstructure and Properties of FeCoCrNiMo/5083 Aluminiummatrix Composites

FeCoCrNiMo high-entropy alloy (HEA) particles enhance the strength of 5083 Al while maintaining favourable plasticity and toughness. To address the strength–ductility constraints of particle-reinforced 5083 Al-matrix composites, composites were fabricated by hot equal-channel angular pressing (ECAP). The contributions of distinct strengthening mechanisms were quantitatively deconvoluted, the formation mechanism of the interfacial diffusion layer was elucidated, and immersion tests of varying duration were conducted to clarify the seawater corrosion behaviour. The composite containing 15 vol% HEA exhibited the best overall mechanical performance, with a hardness of 156.55 HV, a tensile strength of 350 MPa, and an elongation to failure of 12.41%. The improvements are attributed to Hall-Petch strengthening, geometrically necessary dislocation (GND) strengthening, Orowan strengthening, and load transfer. Variations in elemental content and spatial distribution within the diffusion layer are ascribed to differences in diffusivity and diffusion activation energy during hot ECAP, together with inter-element interactions. Mo, Co, and Cr promote the formation of a stable passive film, thereby enhancing corrosion resistance in seawater.