Enhanced Microhardness and Conductivity in a Heat-Resistant Al-Er-Zr Alloy via Optimized Thermomechanical Processing

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.