Assistant professor, Stanford University, Stanford, Calif
Pages: 18 Published: Jan 1977
Substantial progress has been made towards developing a constitutive equation for Zircaloy which is both accurate and applicable to a wide variety of situations and a broad range in temperature. Starting with a previously presented phenomenological model (MATMOD) for nonelastic deformation under complex stress and temperature histories, the equations have been improved so that they now can in-elude important solute effects such as negative strain-rate sensitivity and a plateau in the curve of yield strength versus temperature. Material constants for Zircaloy-2 have been calculated from standard test data (creep and tension tests). Using these constants, simulations of a number of complex situations (all out of pile) have been generated and are compared with the experimental observations. These comparisons include transient-temperature tube-burst results, strain-rate sensitivity versus temperature, effect of cold work on creep rate, unusual drops in creep rate under constant stress but increasing temperature, and peaks in the apparent activation energy. The results indicate that this relatively simple set of equations is capable of a fairly realistic representation of Zircaloy deformation over a wide range of temperature.
zirconium, zirconium alloys, constitutive equations, plastic deformation, creep properties, recovery, solutes, simulation
Paper ID: STP35589S