Study of dislocation substructures in high-Mn steels after dynamic deformation tests

The article presents the dynamic mechanical properties of two types of high manganese austenitic TWIP steels. The investigations were carried out for the wide range of strain rates from 10¯² s¯¹ up to 4×10³ s¯¹ using servo-hydraulic testing machine and split Hopkinson bar for the quasi-static and dynamic loading regime, respectively. The mechanical properties at different strain rates like yield strength and true stress were calculated out on the base of the results of impact tests. In the next step, the microstructure of the analyzed steels after different deformation rates were observed by scanning transmission electron microscopy technique in order to disclose a dislocation structures and mainly the TWIP effect. In the studies observed that with the strain rate increasing yield strength as well as true stress for 0.3 true strain increasing in both steels. The microstructure observations reveal the influence of strain rate on the structure evolution for analyzed steels.