Constitutive modelling of creep-ageing behaviour of peak-aged aluminium alloy 7050

Abstract

The creep-ageing behaviour of a peak-aged aluminium alloy 7050 was investigated under different stress levels at 174° C for up to 8 hInterrupted creep tests and tensile tests were performed to investigate the influences of creep-ageing time and applied stress on yield strengthThe mechanical testing results indicate that the material exhibits an over-ageing behaviour which increases with the applied stress level during creep-ageingAs creep-ageing time approaches 8 h, the material's yield strength under different stress levels gradually converge, which suggests that the difference in mechanical properties under different stress conditions can be minimisedThis feature can be advantageous in creep-age forming to the formed components such that uniformed mechanical properties across part area can be achievedA set of constitutive equations was calibrated using the mechanical test results and the alloy-specific material constants were obtainedA good agreement is observed between the experimental and calibrated results.