The creep-ageing behaviour of a peak-aged aluminium alloy 7050 was
investigated under different stress levels at 174 ◦C for up to 8 h. Interrupted creep tests and
tensile tests were performed to investigate the influences of creep-ageing time and applied
stress on yield strength. The mechanical testing results indicate that the material exhibits
an over-ageing behaviour which increases with the applied stress level during creep-ageing.
As 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 minimised. This feature can be advantageous in creep-age
forming to the formed components such that uniformed mechanical properties across part
area can be achieved. A set of constitutive equations was calibrated using the mechanical
test results and the alloy-specific material constants were obtained. A good agreement is
observed between the experimental and calibrated results.