Analytical determination of forming limit curve for zirlo and its experimental validation

Zirconium alloy sheets used in the nuclear fuel assembly are subject to high temperature and stress, a corrosive and radiation environment and their performance has thus been of big concern. However, knowledge regarding the properties and the formability of zirconium alloys is still lacking. In this paper, strain-based forming limit diagrams (FLDs) are established for the zirconium alloy Zr1Sn1Nb0.1Fe (also called zirlo). The analytical forming limit curve (FLC) varies with forming limit model and yield criterion. To obtain the right hand side of the FLD, we apply the Swift's diffuse necking model, and for the left hand side, Hill's local necking model. Solutions from the analytical method are compared with experimental FLD established based on limit dome height (LDH) tests. Using the strain hardening exponent of a modified stress–strain relation, we could find excellent agreement of the analytical FLC with the LDH-based FLC.