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MM: Fachverband Metall- und Materialphysik

MM 18: Poster Session I

MM 18.21: Poster

Montag, 16. März 2020, 18:15–20:00, P4

Large-scale simulations of plasticity in nanocrystalline Iron — •Hoang-Thien Luu and Nina Gunkelmann — Institute of Applied Mechanics, TU Clausthal, Germany

Shock compression is widely used to investigate the mechanical responses of iron under dynamic loading. It has been long known that α-iron transforms to є-iron under high pressure. Recently, molecular dynamics simulations have shown that plasticity occurs just before the parent phase transforms into є-iron. To provide insights into the interplay of elastic and plastic activities during shocks in iron, we performed atomistic simulations of shock compression of nanocrystalline iron with a mean grain size of 20 nm comprising a total number of 267.5 million atoms. We observed elastic and plastic deformations before the phase transformation takes place. The plastic state is metastable and highly depends on the deformation rate. After a relaxation process of a few picosecond, the structure transforms to a quasi-3D compressed state in which the new phase is stable. The process is ramp time-dependent. In addition, we found that with increasing ramp time of the piston, the period of plasticity is longer.