Heterogeneous Precipitation Behavior of 7085 Aluminum Alloy was Studied by High-Throughput Experiment Based on End-Quenching Technology

Based on the quenching experiments, the precipitation behavior of 7085 aluminum alloy at different quenching rates was investigated through electrical conductivity testing, microstructure characterization, and thermodynamic calculations. The study reveals that as the quenching rate decreases, the electrical conductivity increases, and there is an increase in the types and nucleation sites of quenching precipitation phases. The preferred nucleation sites for precipitation are in the following order: high-angle grain boundaries (HAGBs), low-angle grain boundaries (LAGBs), non-coherent Al₃Zr particles within recrystallized grains (RGs), dislocations, and coherent Al₃Zr particles within subgrains (SGs). The precipitation sequence of quenching phases is as follows: η, T, and Y phases. With the decrease in quenching rate, the η phase is first observed to precipitate at HAGBs, followed by LAGBs, non-coherent Al₃Zr particles within RGs, dislocations, and coherent Al₃Zr particles within SGs. Furthermore, at quenching rates below 152 °C/min, the T phase is observed to precipitate at LAGBs. At a quenching rate of 129 °C/min, the Y phase is observed to precipitate at dislocations.