In this study, large-scale molecular dynamic simulations were performed to analyze the dislocation substructure interaction with various types of obstacles present in microalloyed steels during severe plastic deformation.Specifically, fully functional numerical models boss ga fc ex of the atomic upsetting test were developed, with particular emphasis on the presence of precipitates inside the microstructure grains.The obtained results compared with the microstructural tests, performed using Electron Backscatter Diffraction (EBSD) and Transmission Electron Microscope (TEM) techniques, allowed for a more accurate assessment of the microstructure refinement mechanisms by means of the in-situ recrystallization velgen vff 12 effect in the deformed samples subjected to the multi-axis compression using the MaxStrain system (Dynamic Systems Inc.
, New York, NY, USA).