The effects of material parameters on prediction of forming limit diagrams for CZ1 zirconium alloy sheet using anisotropic yield criterion and M-K analysis

: Little is known about the mechanical property and formability of CZ1 zirconium alloy sheet. In this study, tensile tests of CZ1 sheet were carried out along rolling direction (RD), diagonal direction (DD) and transverse direction (TD). Nakazima tests were conducted to construct the forming limit diagram (FLD) for CZ1 sheet. Three anisotropic yield criteria including Hill48, Barlat89 and BBC2003 were chosen to calibrate the anisotropic coefficients in order to compare the accuracy for anisotropy description. The classical Marciniak-Kuczynski (M-K) model and different yield criteria are applied to predict the forming limit strains theoretically. After comparison, BBC2003+M-K model predicted FLD is in good agreement with the experimental result. Then the effects of material parameters including hardening exponents (n value) and Lankford coefficients (r-values) on the FLD are analyzed with this approach. Furthermore, the relationship between material parameters and formability can be unveiled aiming at providing an optimized direction for formability.