Modelling the Deformation Behavior under Cyclic Loading of Aluminum Alloy Sheet at Cryogenic Temperatures

Abstract

In order to model the deformation behavior under cyclic loading of aluminum alloy sheet at cryogenic temperature, a temperature-dependent macroscopic hardening model was established for AA7075-T6 alloy. The prediction accuracy of the model under monotonic loading and cyclic loading was verified by the cyclic bending experiments of V-shaped components. Results show that the established model can describe the more pronounced Bauschinger effects of aluminum alloys at cryogenic temperatures, including early reverse yielding, transient behavior, and permanent softening. The springback of V-shaped component at cryogenic temperatures is greater compared with room temperature, due to cryogenic strengthening effects of aluminum alloy and the increased stress difference between the inner and outer sides. The prediction error of springback angle under forward and reverse loadings at both 298 K and 77 K is within 10%. Moreover, the model considering the Bauschinger effects exhibit higher springback prediction accuracy for reverse loading at cryogenic temperatures compared with the isotropic hardening model.