Abstract:The effect of double-aging on the microstructure and mechanical properties of a RS / PM A1-Li alloy has been investigated. The results show that the ductility of the alloy can be greatly improved by the treatment of prior-aging at 170℃ For 4 h and second-step aging at 190℃ for 18 h after solid solutioning. The formation of a large amount of composite precipitates (AlLi₃/Al₃(Li,Zr)) with suitable size, narrowing of Fσ' (Al₃Li) precipitate-free zone (PFZ) at grain boundaries and more dispersive precipitation of S' (A1₂CuMg) phases along substructures are responsible for the improvement of the ductility of the studied alloy.

Key words: AI-Li alloy  rapid solidification  double-aging