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Herein, the effects of pre‐deformation to higher levels on mechanical properties, strengthening contribution, and microstructures of 2A55 Al–Li alloy are investigated. It is shown in the results that the tensile strength of 2A55 Al–Li alloy approaches 660 MPa with an elongation of 9.28% after 15% pre‐deformation. The strengthening contribution from precipitates and strain is calculated based on detailed microstructure information. The strengthening model reveals that the joint strengthening contribution of T1 and θ′ precipitates decreased with increasing the pre‐deformation. In contrast to the decreased strengthening contribution of precipitates in severely pre‐deformed samples, the part from pre‐deformation dramatically increases thus leading to the enhanced yield strength. It is revealed that the recovery of dislocation structure introduced by pre‐deformation is suppressed during artificial aging. Additionally, herein, the trade‐off between the strengthening contribution and elongation is presented, which can be optimized by selecting proper pre‐deformation processing. [ABSTRACT FROM AUTHOR]

• TTP and TTT diagrams of 2050 Al-Li alloy have been established. • The microstructure evolutions during interrupted quenching have been in-depth investigated. • The effects of microstructure evolution on tensile properties under different cooling rates has been investigated using cold-rolled thin sheets. The quench sensitivity of 2050 Al-Cu-Li alloy was determined by the time-temperature-transformation (TTT) curves and time-temperature-property (TTP) curves based on conductivity and hardness. Additionally, a novel end quenching test was used to investigate the quench sensitivity of cold-rolled sheets with a thickness of 2 mm which cannot be tested by conventional methods. The microstructure evolution during interrupted quenching (IQ) treatment and end quenching test was studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The precipitation and coarsening of Cu-rich phases during quenching are the main factors affecting the quench sensitivity of the alloy. Meanwhile, these Cu-rich phases lead to the uneven distribution of precipitates (T 1 and θ′), which results in the decreased tensile properties. The influence of precipitate free zones (PFZs) on elongation during end quenching test was clarified and the high quench sensitive temperature zone was found to be 260 ~440 °C. This work can help to optimize the quenching process and improve the mechanical properties of the 2050 Al-Cu-Li alloy. [ABSTRACT FROM AUTHOR]