Finite Element Modeling of Phase Transition in Zirconia Using MOOSE

MOOSE (Multiphysics Object Oriented Simulation Environment) is a finite element framework software developed by the Idaho National Laboratory. Its open source and parallelization capabilities make it powerful and easily accessible to use for mesoscale computational modeling and upscaling to larger domains. MOOSE modules allow for easy implementation of various physics modeling conditions. We utilize MOOSE’s phase field module to model the tetragonal to monoclinic (t→m) phase transition in zirconia, a material known for its strength, fracture toughness, and low thermal conductivity. t→m transition is the mechanism underlying the zirconia self-healing against crack propagation. In this work we applied the time-dependent Ginzburg-Landau equations to evaluate the temporal and spatial evolution of t→m. Phase field modeling is an extremely powerful method in model mesoscale phenomenon and it has been shown to accurately model the t→m martensitic phase transformation in zirconia. A minimization technique is used to track all energies within a system, making it possible to calculate surface energies and increase stability of the system. We present preliminary results of using the phase field method to model the t→m transformation with MOOSE

Transformations and cracks in zirconia films leading to oxidation of zircaloy

This work was aimed to identify the root cause of breakaway oxidation of Zircaloy and the origin of Zircaloy cladding failure. Circumferential compressive stress is highly promoted by tetragonal to monoclinic phase transition. Therefore, this transformation is rather beneficial as it will increase the time to attain critical oxide thickness (at which the stress changes from compressive to tensile), and thus retards breakaway oxidation

Transformations and cracks in zirconia films leading to oxidation of zircaloy

This work was aimed to identify the root cause of breakaway oxidation of Zircaloy and the origin of Zircaloy cladding failure. Circumferential compressive stress is highly promoted by tetragonal to monoclinic phase transition. Therefore, this transformation is rather beneficial as it will increase the time to attain critical oxide thickness (at which the stress changes from compressive to tensile), and thus retards breakaway oxidation