Mechanism and optimization for the effect of solid solution treatment on microstructure and properties of recycled 7050-T7451 plate

Abstract

The aviation grade-maintained recycling of 7XXX aluminum alloy has been achieved. However, there is still a lack of research on the optimization of the microstructure and properties of recycled aviation alloy. This work explores the effect of solid solution treatment on the microstructure and properties of recycled 7050-T7451 plate and its mechanism. The mechanism of “solid solution synergistic regulation of mechanics and corrosion resistance” was elucidated. After the solid solution of recycled aviation aluminum plates, the incomplete dissolution of Al2CuMg caused stress concentration and deteriorated the mechanical properties. In addition, the Cu clusters promoted the anodic dissolution of Al, reducing the corrosion resistance. Therefore, the solution temperature of recycled 7050 sheet was increased from 470 °C to 480 °C for 100 min. And the residual Al2CuMg was reduced by 56.6%, which synergistically improved the mechanical and corrosion resistance properties of recycled 7050 plates. The mechanical properties of two sets of recycled 7050-T7451 plates reached 516.3 MPa and 522.0 MPa, with elongation 17.5% and 17.3%, and there was no intergranular corrosion. This work explored the regulation mechanism of microstructure and properties of recycled 7050-T7451 plate, laying the foundation for the application of recycled aviation aluminum alloys.