Abstract:In order to clarify the influence of grain size on cyclic deformation response of superalloy sheets and springback behavior, cyclic loading-unloading and shearing tests were performed on the superalloy foils with 0.2 mm in thickness and diverse grain sizes. The results show that, the decline ratio of elastic modulus is weakened with increasing grain size, and the Bauschinger effect becomes evident with decreasing grain size. Meanwhile, U-bending test results determine that the springback is diminished with increasing grain size. The Chaboche, Anisotropic Nonlinear Kinematic (ANK) and Yoshida-Uemori (Y-U) models were utilized to fit the shear stress-strain curves of specimens. It is found that Y-U model is sufficient of predicting the springback. However, the prediction accuracy is degraded with increasing grain size.

Key words: grain size effect; cyclic deformation; superalloy foil; hardening model; springback prediction