Simulations of post-recrystallization grain growth in monolithic U–10Mo fuel processing

The Potts Model was used to simulate the post-recrystallization grain growth behavior of U-10 wt% Mo (U–10Mo). The fabrication process for monolithic U–10Mo fuels involves multiple stages of rolling, during which spatially heterogeneous distributions of second phase particles form in the alloy microstructure. These particles can strongly affect the post-recrystallization grain growth process. Absent particle dissolution effects, U–10Mo grain growth has been observed stagnating at increasing grain size with increasing annealing temperature. In this work, we simulate this effect in the Potts Model by making adjustments to the non-physical Monte Carlo temperature. This modification was used to account for the weakening pinning effect of the second phases with elevated annealing temperature. Simulated average grain sizes and grain size distributions were compared with experimentally obtained results for 700 °C, 800 °C, and 900 °C anneals of duration up to 240 h. These simulations achieved reasonable agreement with experimentally observed grain growth behavior, but showed narrower grain size distributions. It is believed that this disagreement originates from the formation of bands of second-phase particles during rolling. These results demonstrate the capability to evaluate the post-recrystallization grain growth behavior for U–10Mo as a function of previous homogenization, rolling, and annealing treatments.