Болеста А.В.   Fomin V.M.  

Molecular dynamics simulation of shock-wave loading of copper and titanium

Reporter: Болеста А.В.

The report presents a comparative molecular dynamics (MD) analysis of the behavior under shock-wave loading of two nanocrystalline metals with different crystal structures. These are copper and titanium with a face-centered cubic (fcc) and hexagonal close-packed lattice (hcp), respectively. At the same time, both these materials demonstrate a solid state phase transition at a certain shock wave strength. The structure of copper changes to a body-centered cubic (bcc) lattice at a pressure in a shock wave greater than 100 GPa, which was predicted by us earlier, theoretically and experimentally, can be shown at the present time only indirectly. The change in the crystal structure of titanium was demonstrated experimentally and occurs at a pressure greater than about 30 GPa. MD calculations allow us to reveal differences in the structure and width of the front of the shock wave in these two metals. Much attention was paid to the study of deformation mechanisms and structural transformations in the loading regimes near phase transitions. The possibility of using a phase transition behind a shock wave with further unloading for designing nanocrystalline materials with a reduced grain size is also shown.

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