The effects of Sc, Mg and Si elements in an Al-Cu alloy have been studied by means of hardness tests and transmission electron microscopy analysis. The experimental results show that additions of Sc, Mg and Si can improve the heat resistance of the Al-Cu alloy. The Sc/Mg/Si segregation-sandwiched structure is the most stable, when compared with Sc segregation or Si/Sc co-segregation at the interface of θ′/Al. The additions of Si and Mg promote the aging–hardening response of the Al-Cu alloy. Mg is a micro-alloying element with great potential in stabilizing the size of θ′ phases, which further promotes the number density greatly. Consequently, the Al-Cu alloy achieves a high strength, matched with excellent thermal stability, due to the microalloying of Sc/Mg/Si solutes.

To meet the demand for high-performance heat-resistant aluminum alloy conductors in energy transmission, this study systematically explores the effects of synergistic aging and deformation treatment on the microstructure, mechanical properties, and heat resistance of Al-0.04Er-0.08Zr alloy. Through isochronous/isothermal aging, rolling with varying deformation amounts, and microstructural characterization coupled with performance testing, the following findings emerged: 425 °C represents the peak aging temperature, at which a dispersed L1₂ structure of Al₃(Er_1−xZr_x) composite precipitates with an average size of 4 nm is formed; Dispersed L1₂ structure Al₃(Er_1−xZr_x) composite precipitation phase achieved an alloy hardness of 49.45 HV and electrical conductivity of 58.68% IACS; the synergistic treatment of peak aging (425 °C) with 60% deformation amount yielded optimal comprehensive properties. After 150 h of isothermal annealing at 350 °C, hardness decreased by less than 5%, and the alloy demonstrated stable service life of approximately 40 years at 227 °C based on Arrhenius model extrapolation. This study reveals the synergistic regulation mechanism between deformation and aging, providing theoretical support and technical reference for developing low-cost, high thermal stability, and high-conductivity aluminum alloys.