Speaker
Description
Modern industrial alloys for nuclear energy are complex multicomponent materials with a wide range of concentration of components. Precipitates of secondary phases form during thermal and radiation aging. These precipitates play crucial role in hardening of the materials. Experimental verification of promising candidate alloys is expensive and time-consuming process. Therefore, methods of atomistic modeling can be used for preliminary analysis of candidate materials. Accurate and computationally effective methods are required for correct prediction of alloys behavior.
Coupling of DFT and kinetic Monte Carlo (kMC) is the high-precision approach to model evolution of multicomponent systems. However, thousands of DFT calculations are required for single simulation. Efficient representations of local atomic environments as cluster expansion [1] is a promising way to speed up on-lattice calculations.
We use alternative to the cluster expansion method [2]. It consists decomposing the interaction energy into contributions of local atomic environments, and representing the contributions as low-rank multidimensional tensors. Ballistic mixing [3] and vibrational entropy is also taken into account. All features are integrated with kMC. Thus, we accurately model solid solution stability of multicomponent systems during neutron and ion radiation aging.
In this work, the proposed approach is employed to investigate the kinetics of the formation of secondary phases in Fe-Cr, Fe-Cu and Fe-Cr-Si-Ni-Mn systems in a wide range of temperatures. We observe the formation of the Cr-rich, Cu-rich and Ni-Si-Mn precipitates, respectively. Obtained data are in good agreement with the results of experimental studies. The developed technique can be used for prediction of the formation of the precipitates in industrial alloys with a close chemical composition.
References:
1. Lavrentiev, M. Yu, et al. Physical Chemistry Chemical Physics 16.30 (2014): 16049-16059.
2. Shapeev, A. Computational Materials Science 139 (2017): 26-30.
3. Novoselov, I.I. Journal of Nuclear Materials 546 (2021): 152762
| Speaker Country | Russia |
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