Modeling of Al-Cu solid solution compression with accounting of phase transitions and dislocation plasticity N. A. Grachyova∗, E. V. Fomin, A. E. Mayer Department of General and Theoretical Physics, Chelyabinsk State University, Chelyabinsk 454001, Russian Federation ∗ nagra45da@gmail.com Keywords: molecular dynamic, phase transition, plasticity. The problem of studying plastic deformation in metals under complex dynamic loading and the associated change in their defect structure is still relevant. The plastic deformation process in pure metals is often accompanied by the formation and interaction of dislocations. In some situations, the contribution of phase transitions exceeds the dislocation plasticity contribution to stress relaxation under dynamic tests. In our work, we developed a stress relaxation model using machine learning methods and applied it to simulate uniaxial compression of the material. Molecular dynamics (MD) simulations using the LAMMPS software package [1] and the ADP potential [2] of Al-CU solid solution compression showed the nucleation and movement of dislocations as well as the phase transition of the crystal structure. These processes lead to a significant relaxation of shear stresses. The parameter fitting procedure for the developed phase structure evolution model and the dislocation plasticity model from the previous literature [3] was carried out by the Bayesian method, which allows us to calculate a quasi-probability characterizing the degree of coincidence of the calculated curves with the reference data. An artificial neural network trained on the results of MD calculations was used as the equation of state of Al-Cu solid solution at varied concentrations of components. Acknowledgements The study was funded by a grant from the Russian Science Foundation, Project No 20-11-20153, https://rscf.ru/en/project/23-11-45024/. References [1] Plimpton S. Fast Parallel Algorithms for Short-Range Molecular Dynamics // J. Comput. Phys. – 1995. – V. 117. – P. 1–19. [2] F. Apostol, Y. Mishin. Interatomic potential for the Al-Cu system // Phys. Rev. B. – 2011. – Vol. 83. – P. 054116 [3] T.V. Popova, A.E. Mayer, K.V. Khishchenko. Evolution of shock compression pulses in polymethacrylate and aluminum // J. Appl. Phys. – 2018. – 123, 235902. 91
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