Enhanced dynamic mechanical properties and resistance to the formation of adiabatic shear band by Cu-rich nano-precipitates in high-strength steels

Cu-rich nano-precipitate strengthened steel is a kind of promising impact-resistant structural materials due to its perfect combination of strength and ductility. In this study, the effects of the Cu-rich nano-precipitates on the dynamic mechanical properties, deformation resistance and adiabatic shear band formation were systematically investigated. It is found that the Cu-rich nano-precipitates can effectively improve the strength at high strain rate during dynamic deformation. The maximum flow stress reaches ~2565 MPa at the strain rate of 6000 s−1, presenting the outstanding dynamic mechanical properties. The nano-precipitate-strengthened steel has a great positive strain rate sensitivity at a high strain rate, showing the excellent resistance to high-speed deformation and delayed fracture. The nano-precipitates can effectively hinder the formation and development of the adiabatic shear bands and improve significantly the maximum flow stress and microstructure stability during the high-speed impact. [Display omitted] •Cu-rich nano-precipitate strengthened steel presents the outstanding dynamic mechanical properties.•The precipitation of new nano-precipitates during high speed impact further increases the strength at high strain rate.•The nano-precipitates can effectively delay the dynamic recrystallization and the formation of TSB.