The thermo-mechanical behavior and texture evolution of two overaged Al 7056 alloy plates, in T761 and T721 tempers, are measured over a wide range of strain rates (10 - 3 × 10 s) and temperatures (22-300 °C) under uniaxial tension and compression along the thickness direction, i.e. normal to the plate surface. A detailed study of the initial microstructure reveals an increase in precipitate size and decrease in density of precipitates, as the alloy is aged from the T761 to T721 temper; which in turn affects the flow stress and strain hardening behavior. Differences in flow strength and strain hardening rate, as well as tension-compression asymmetry in the two tempers, are apparent at the lower temperatures (22 °C & 100 °C) and decrease significantly at the higher temperatures (200 °C & 300 °C). Furthermore, initial texture measurements show a strong texture gradient along the normal direction (ND) of the plate. This texture gradient affects the ultimate stress insignificantly. However, it does have a considerable effect on the failure strains of specimens taken from different locations through the thickness. A transition from shear fracture at and below 200 °C to cup and cone fracture mode above 200 °C is observed in tension. Both tempers exhibit a positive strain rate sensitivity (SRS) that is dependent on temperature and strain rate. A sharp decrease in flow stress is found at 300 °C. The Khan-Liu (KL) model is modified to correlate with the measured thermo-mechanical responses of the two tempers over the studied, wide range of strain rates and temperatures. There is a close correlation between simulated and observed results.

A thermally-activated constitutive model is developed based on dislocation interactions, crystallographic orientations and microstructural evolution to describe the elasto-plastic stress-strain behavior during multi-axial loading. The aim is to contribute to the quantification of complex strain path response in solid solution strengthened alloys. In detail, dislocation/dislocation interactions are incorporated in the model to quantify latent and kinematic hardening phenomena during loading path changes. Dislocation density-based constitutive relations are included to account for dislocation features such as dislocation forests, walls and channels. Moreover specifically, dislocation/solute atom interactions are also considered in order to account for both dynamic and static strain aging as well as static recovery. The model is validated against multiple multi-axial data sets for AA5754-O with changes of loading path and various degrees of pre-strain and time intervals between tests.