Enhancing aluminum crossover alloy fabrication via powder metallurgy

• Spark plasma sintering (SPS) enabled near-full-density Al–Mg–Zn–Cu compacts. • T6 aging at 130 °C promoted fine T′ + η′ co-precipitation in the matrix. • Dominant T′ precipitates provided Orowan strengthening with η′ shearing. • The crossover alloy achieved 215.6 HV and 485 MPa yield strength after T6. • T′ -rich microstructure reduced galvanic contrast and improved corrosion resistance. Al–5.5 wt% Mg–5.5 wt% Zn–0.5 wt% Cu crossover alloy powders were consolidated by spark plasma sintering (SPS) and subsequently subjected to T6 heat treatment to evaluate precipitation behavior and mechanical performance. Microstructural characterization revealed pronounced Mg–Zn–Cu segregation along grain boundaries in the as-sintered state; after T6 treatment, these segregations produced a uniform population of fine intragranular precipitates. Composition design (Zn/Mg ≈1) promoted dominant T′ (Mg 32 (Al, Zn) 49 ) formation with concurrent η′ precipitation, a combination expected to enhance strengthening while mitigating galvanic contrast at grain boundaries. The results of mechanical properties showed that the crossover alloy after T6 treatment exhibited high hardness (215.6 HV) and elastic modulus (89.2 GPa), with compressive yield and ultimate strengths of 485 MPa and 570 MPa, respectively. The observed simultaneous operation of shearing ( T ′) and Orowan-type ( η ′) strengthening mechanisms, together with the homogeneous precipitate distribution afforded by SPS, underpins the alloy’s enhanced strength without excessive loss of corrosion resistance. These results demonstrate that tailored Zn–Mg balancing and SPS processing provide an effective route to combine the formability of 5xxx-series alloys with the precipitation strengthening of 7xxx-series alloys for high-performance, corrosion-resistant aluminum components.