Quantitative characterization of aging precipitation behavior and strengthening mechanisms of Al–Li alloy under pre-deformation

The synergistic effect of pre-deformation (0-10%) on the aging precipitation behavior, microstructure evolution and strengthening mechanisms of 2195 Al-Li alloy. Results demonstrate that pre-deformation significantly enhances aging kinetics, reducing the peak-aging time from 30 h (0% pre-deformation) to 18 h (10% pre-deformation). The optimal pre-deformation level of 4% yielded a superior combination of yield strength (525.01 MPa), ultimate tensile strength (550.57 MPa), and elongation (10.01%). Compared to the non-deformed alloy, the pre-deformed (4%) alloy exhibited a significant increase in dislocation density from 1.45×10 14 m -2 to 5.12×10 14 m -2 . This enhanced dislocation density promoted the nucleation of considerably finer T 1 precipitates, reducing their average diameter from 136.54 nanometers to 65.59 nanometers, while simultaneously suppressing the formation of the θ′ phase. Pre-deformation effectively lowered the activation energy required for T 1 precipitation from 159.78 kJ/mol to 153.40 kJ/mol, which led to an acceleration in nucleation kinetics. Quantitative strengthening mechanisms analysis indicated precipitation strengthening (234.8 MPa) as the dominant contributor in pre-deformed alloys. The study provides a ageing precipitation kinetics framework for optimizing pre-deformation parameters to achieve synergistic strength-ductility improvements in Al-Li alloys.