Effect of Orientation and Overaging on the Creeo and Creep crack growth Properties of 2xxx Aluminium Alloy Forgings

Long-term high temperature properties of aluminium alloy forgings are widely affected by the extent and direction of plastic flow as well as by the heat treatment and exposure causing overaging processes. The classical creep crack propagation models, for which the material is often considered as isotropic and microstructurally stable, must be adapted to take into account the effects of crystal orientation and of overaging. After presenting the creep behaviour of 2014 and of 2016 Al alloy forgings in different sampling directions and overaging conditions, FE simulations of the crack propagation of CT specimens sampled in different directions were carried out. The possibility to account for the progressive overaging of the material was also taken into account in the model.