Design and characterization of a novel lightweight multicomponent alloy Al₅₈Zn₂₈Mg₆Si₈

This paper presents a novel multicomponent alloy Al₅₈Zn₂₈Mg₆Si₈, with a density of 3.46 g/cm³, which incorporates concepts from high entropy alloys. The optimum alloy composition was determined using the CALPHAD approach and binary and ternary diagrams. Microstructural and thermal analyses, including scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and differential scanning calorimetry, revealed a complex phase structure consisting of FCC, HCP, and Laves phases, as well as a metastable miscibility gap. The alloy was heat treated, and the microstructure of each condition was evaluated. The solubilized state exhibited a maximum hardness of 250 HV. Transmission electron microscopy results showed that the alloy undergoes spinodal decomposition during the solution treatment. This study provides valuable information for the future design of lightweight multicomponent alloys combining experimental techniques with the CALPHAD approach.