September 24, 2024
Journal Article
Microstructure-Process Relationships in Monolithic U-10Mo Fuel Foil Multiple-Pass Rolling: A Simulation Parameter Study
Abstract
In this work, the microstructures of U-10Mo foils that emerge over multiple stages of hot-rolling and reheating were evaluated using the Kinetic Monte Carlo Potts Model coupled with the finite element method. Hot rolling and reheating refine the U-10Mo foil microstructure, but the relationships between the foil microstructure and recrystallization behavior over multiple successive reductions have not yet been well quantified. Simulations were employed to forecast the impact of hot rolling reduction, grain size variations, and uranium carbide (UC) distribution on the recrystallization kinetics and microstructural evolution of U-10Mo alloy. Initial homogenized grain sizes varying from 100 microns to 1 mm and UC volume fractions ranging from 0-2 vol% were parametrically evaluated as a part of this study. The simulation results for single-pass rolling and reheating support findings from our earlier modeling analyses, which indicated that larger rolling reductions lead to more grain refinement upon reheating, and the UC distribution only weakly influences the overall recrystallization kinetics within the ranges investigated. Further, these simulations indicated that the homogenized grain size has little effect on U-10Mo recrystallization kinetics after the first pass of rolling, and nearly uniform refinement is achieved regardless of rolling reduction percentage per pass after a combined 50% total reduction by hot rolling and 40 min of reheating at 700 °C. However depending on the heat treatment, this can lead to significant differences in the distribution of strain within the final microstructures, which can slow grain coarsening over the final anneal. The implications of these results on U-10Mo fuel foil fabrication procedures are discussed.Published: September 24, 2024