Synergistic Effects of Pre-Stretching and Aging Temperature on Precipitation Behavior and Damage Tolerance of an Al-Cu-Li Alloy

This study systematically investigates the synergistic effects of the pre-stretching deformation and aging temperature on the precipitation behavior and mechanical properties of an Al-Cu-Li alloy. The results indicate that increasing the pre-stretching deformation significantly refines and increases the number density of <i>T</i>₁ and <i>θ</i>' phases while optimizing the grain boundary precipitate morphology, thereby enhancing the fracture toughness and fatigue resistance without compromising the high strength. In contrast, elevating the aging temperature promotes the coarsening of the <i>T</i>₁ phase, inhibits <i>θ</i>' precipitation, and coarsens the grain boundary precipitates, leading to a deteriorated damage tolerance. By matching 3.5~4.5% pre-stretching with 145~155 °C aging, a synergistic optimization of ultra-high strength and damage tolerance can be achieved.