The lightweight, unconventional 2055 Al-Cu-Li-Ag alloy exhibits an excellent specific strength in the T83 state, but no literature reports the effects of overaging on this alloy. In the present work, the suitability of the alloy for lightweight components operating at high temperature is evaluated. Thermal exposure in the range 215–305 °C was investigated, highlighting its consequences on both microstructure and mechanical properties. In the most severe overaging state (24 h at 305 °C), the typical T₁ precipitates (Al₂CuLi) are dissolved, leading to the formation and coarsening of ϑ’ and Ω phases. In all overaging conditions, the alloy performance was superior or at least comparable to that of another third generation Al-Li alloy, AA2099, which is characterised by a slightly lower density and encouraging mechanical properties for high temperature applications. Compared to AA2099, the AA2055 alloy provides a higher specific strength (the basic requirement for mass savings) both in the T83 and in the most severe overaging state (24 h at 305 °C). This work highlights that AA2055 is a promising candidate for lightweight components operating up to 305 °C, and it lays the basis for high temperature tests of the alloy.

轻巧，非常规的2055 Al-Cu-Li-Ag合金在T83态下表现出出色的比强度，但没有文献报道过时效对该合金的影响。在目前的工作中，评估了合金对在高温下工作的轻质部件的适用性。研究了在215–305°C范围内的热暴露，突出了其对微观结构和机械性能的影响。在最严重的过度老化状态（在305°C，24小时）下，典型的T ₁析出（Al ₂CuLi）溶解，导致ϑ'相和Ω相的形成和粗化。在所有的过时效条件下，该合金的性能均优于或至少可与另一种第三代Al-Li合金AA2099相比，该合金的特点是密度略低，并且在高温应用中具有令人鼓舞的机械性能。与AA2099相比，AA2055合金在T83和最严重的过时效状态（在305°C下为24小时）提供更高的比强度（节省质量的基本要求）。这项工作强调了AA2055是在305°C下工作的轻质部件的有希望的候选者，并且为合金的高温测试奠定了基础。