Multiscale Analysis of Viscoplastic Behavior of Recrystallized Zircaloy-4 at

• Published in: Journal of ASTM International 2011-01, Vol.8 (1), p.1-19
• Main Authors: Priser, Mathieu, Rautenberg, Martin, Cloué, Jean-Marc, Pilvin, Philippe, Feaugas, Xavier, Poquillon, Dominique
• Format: Article
• Language: English
• ISSN: 1546-962X; 1546-962X
• DOI: 10.1520/JAI103015

Zirconium alloys are used in the nuclear industry as cladding tubes to prevent the fissile material from leaking into the coolant as the first safety wall of nuclear fuel. More and more requirements on fuel performance lead to stronger mechanical solicitations and integrity of cladding tubes has to be guaranteed. In this framework, the polycrystalline models, which are based on plasticity mechanisms, have interesting advantages compared to phenomenological ones. Some previous studies have shown that a polycrystalline approach could be very useful to describe the mechanical behavior of zirconium alloys. This modelling strategy has been successfully applied to fresh material and also, more recently, to irradiated material. The micromechanical approach has been developed in the light of transmission electron microscopy (TEM) observations. These experiments have been achieved to identify the main deformation mechanisms, which occur in several grains of relaxed and crept Zircaloy-4 samples. The main purpose of this paper is to describe an improved micromechanical model able to reproduce both the anisotropic creep behavior and the elasto-plastic behavior of unirradiated recrystallized Zircaloy-4 at 400 ° C. Finally, the quantitative analyses, which have been carried out with TEM correspond well with the results provided by the micromechanical approach.