Experimental study and creep constitutive modeling for 2219 aluminum alloy under tension and compression conditions

The creep deformation and mechanical properties of 2219 aluminum alloy were experimentally investigated under both tension and compression at the temperature of 165 °C for different time. The results indicated that the creep deformation under tensile stress was greater than that under compressive stress. As the stress level increases, the compressive creep rate showed more significant increase. The yield strength after compressive stress creep-ageing was higher than that after stress-free ageing, with the lowest strength observed in the tensile-aged sample. Overall, the average phase length after compressive stress creep-ageing was larger than after tensile stress ageing. Under tensile stress, the number and size of precipitates at small angles to the stress direction were larger than those perpendicular to the stress direction. In contrast, under compressive stress, this relationship was reversed, and the preferential orientation of phases became more pronounced with ageing time. A unified, physics-based creep-ageing constitutive model, accounting for the orientation of precipitation, was developed for both tensile and compressive stress conditions. The predicted results were in good agreement with the experimental data. These findings, along with the developed model, provide a theoretical and simulation basis for precise creep-ageing forming of components under complex stresses.