FRACTURE MECHANISM OF PRE-DEFORMATION-AGED Al-2.73Li ALLOY

The fracture mechanism of deformation-aged Al-Li alloy was approached by investigating the influence of prior cold deformation on the precipitation kinetics as well as the behaviours of work hardening and fracture for Al-2.73Li alloy.The experimental results show that the work hardening rate and the strength are increased and the ductility is decreased by prior cold deformation.The decrease in ductility is mainly due to the cell dislocaton substructure distrib- uted inhomogeneously and the hardening of precipitate free zones at grain boundaries caused by prior cold deformation.The failure mode in the alloy is a mixed integranular and transgranular one.The tendency of intergranular fracture is intensified through the deformation-aging.The mechanisms of intergranular failure in the alloy are different under various deformation-aging treatments.