Development of a grain growth model for U3Si2 using experimental data, phase field simulation and molecular dynamics

• Published in: Journal of nuclear materials Vol. 532; no. C; p. 152069
• Main Authors: Cheniour, Amani, Tonks, Michael R., Gong, Bowen, Yao, Tiankai, He, Lingfeng, Harp, Jason M., Beeler, Benjamin, Zhang, Yongfeng, Lian, Jie
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15-04-2020; Elsevier BV; Elsevier
• Subjects: Computer simulation; Experimental data; Grain boundaries; Grain boundary mobility; Grain growth; Grain size; Growth kinetics; Growth models; Isothermal annealing experiments; Mobility; Molecular dynamics; Particle size; Phase field; Temperature; U3Si2; Uranium silicide; U3Si2; Grain boundary mobility; Isothermal annealing experiments; Grain growth; Phase field
• ISSN: 0022-3115; 1873-4820
• DOI: 10.1016/j.jnucmat.2020.152069

The purpose of this work is to develop a model for normal grain growth in U3Si2. The average grain boundary energy was determined from previously published molecular dynamics simulations. The grain growth kinetics were quantified at various temperatures by annealing nanocrystalline samples. The mobility was determined by comparing phase field grain growth simulations to the experimental data. From these various methods, we found that the average grain size D in U3Si2 can be estimated over time t using the equation D2−D02=2αMγt, where D0 is the initial average grain size, the geometry factor α=0.96, the average grain boundary mobility M=6.30×10−18e−0.33[eV]kbTm4/(Js) with the Boltzmann constant kb and temperature T, and the average grain boundary energy has been found as a function of temperature, e.g. γ¯=0.83 J/m2 at 673 K.
•The grain growth constant and activation energy were obtained from isothermal annealing experiments on U3Si2 lamellae.•The grain growth geometric constant was calculated using several 3D phase field grain growth simulations.•The grain boundary mobility was determined from experimental data, grain boundary energy, and phase field simulations.•More grain growth occurs in U3Si2 than in UO2 at 1200 K.•Grain growth is more rapid in UO2 than in U3Si2 at their respective centerline temperatures.