Tribute to Dr. Javier Signorelli: Effect of Helical Climb on Irradiation-Induced Deformation of Pressure Tubes

Abstract

In earlier works, we expounded a rigorous constitutive framework for coarse-grained zirconium alloys under irradiation, exposing the essential structure of constitutive laws by combining a two-scale description with internal variables. Thus, the structure of local constitutive laws within individual grains follows a thermodynamic formulation that accounts for point defects nucleated by radiation and deformation produced solely by dislocation glide and climb, while the structure of the overall constitutive relations for the polycrystalline aggregate is obtained through homogenization. However, when evaluating the single crystal creep compliance, the selected microstructure leads to a deficient macroscopic response. While this is not a limitation for the Reuss model, it can be a limiting factor for a self-consistent approach. Finally, based on experimental observations of irradiated materials, we propose incorporating helical climb into the microstructural description.