Mesoscale model for fission-induced recrystallization in U-7Mo alloy

Abstract

A mesoscale model is developed by integrating the rate theory and phase-field models and is used to study the fission-induced recrystallization in U-7Mo alloy. The rate theory model is used to predict the dislocation density and the recrystallization nuclei density due to irradiation. The predicted fission rate and temperature dependences of the dislocation density are in good agreement with experimental measurements. This information is used as input for the multiphase phase-field model to investigate the fission-induced recrystallization kinetics. The simulated recrystallization volume fraction and bubble-induced swelling agree well with experimental data. The effects of the fission rate, initial grain size, and grain morphology on the recrystallization kinetics are discussed based on an analysis of recrystallization growth rate using the modified Avrami equation. We conclude that the initial microstructure of the U-Mo fuels, especially the grain size, can be used to effectively control the rate of fission-induced recrystallization and therefore swelling.

A review: applications of the phase field method in predicting microstructure and property evolution of irradiated nuclear materials

“…Table 1. Applications of PF method in radiation-induced microstructure evolution Radiation-induced microstructure evolution phenomenon References Gas bubble evolution [54][55][56][57][58][59][60][61][62] Void formation and evolution [63][64][65][66][67][68][69][70][71][72][73] Void and gas bubble lattice formation 62,74 Void migration [75][76][77] SIA loop growth and sink strength [78][79][80] Segregation and precipitation [81][82][83][84][85][86][87][88][89][90] Grain growth and recrystallization [91][92][93][94][95] A review: applications of the phase Y Li et al…”

“…[91][92][93][94][95] These modeling expanded the pure grain growth model developed by Chen and Yang 120 with accounting for the effects of pore/void or gas bubble pinning, 91,92 temperature gradient effect, 93 initial grain structure, 94 and dislocation density, 95 respectively. The nonconserved variables {η 1 (x,t),η 2 (x,t),···,η N (x,t)} were chosen to represent the grain orientations.…”

“…Very recently, Liang et al 95 developed a PF model of radiationinduced recrystallization in U-Mo fuels model. In the model, the rate theory was used to calculate the critical dislocation density, the size and density of critical nuclei of recrystallization grains, which were the input determining the initiation of recrystallization and the nucleation rate of subgrains in the PF modeling.…”

“…Applications of the PF method in predicting microstructure evolution in solidification and solid state phase transition have been reviewed in several articles. [46][47][48][49][50][51][52][53] During the past decade, the PF approach has been applied to study microstructure evolutions in irradiated nuclear materials [91][92][93][94][95] Millett and Tonks reviewed the application of PF models in predicting void and gas bubble evolution. 96 The PF method also has been used to study the effect of microstructures on material property degradation including radiation-induced void and gas bubble swelling.…”

Model Development in MARMOT for High Burn-up Structure Formation

“…A few phase-field models of recrystallization exist in literature [18][19][20]. These models account for both interfacial and strain energies and hence can simulate the growth of recrystallized grains at the expense of damaged/deformed grains.…”