Dynamic response and adiabatic shear behavior of β-type Ti–Mo alloys with different deformation modes

This study examined the dynamic compressive properties and adiabatic shear behavior of β-type Ti–10Mo, Ti–15Mo, and Ti–22.5Mo alloys whose deformation modes are stress-induced α''-martensitic transformation combined with {332} twinning, {332} twinning, and dislocation slip under quasi-static loading, respectively. Based on the characterization of deformation microstructures, the deformation modes did not undergo significant change regardless of quasi-static and dynamic conditions. Their yield strength increased remarkably when the strain rate rose from 10−3 s−1 to 103 s−1, thus exhibiting the strain rate strengthening effect. The impact absorbed energy showed an increasing trend with a rise in strain rate, and the highest value (319.2 J/cm3) was observed in the Ti–15Mo alloy at a strain rate of 3956 s−1. The {332} twinning deformation led to a high capacity for strain hardening, which delayed the formation of adiabatic shear bands, comprising the ultra-fine β-matrix and nano-scale ω-phase. Moreover, the deformed twins provided a tortuous and bifurcated path to enhance the propagation resistance of adiabatic shear bands, thereby further consuming the impact energy.