Establishment of ductile fracture locus of 2219 aluminum alloy at cryogenic temperature

Abstract Cryogenic forming has been used to manufacture intricate curved surface aluminum components. The special geometry and mold constraints cause the stress state to continuously evolve. Coupling with the cryogenic temperature makes the deformation process more complicated. Especially for the final fracture, which greatly determines the forming quality of the components. Thus, the cryogenic fracture behavior of three typical stress states was obtained by conducting tensile experiments. Fracture strains and stress paths were obtained using a hybrid numerical-experimental method. Finally, the cryogenic fracture locus was obtained based on the MMC ductile fracture criterion. The results indicate that the AA2219-O exhibits superior ductile fracture properties at cryogenic temperature. The fracture strain of AA2219-O was increased by 52.6% at the uniaxial tensile stress state, and by up to 80.0% at under plane strain stress state. This research has a guiding significance for cryogenic forming.