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

This study examined the dynamic compressive properties and adiabatic shear behavior of beta-type Ti-10Mo, Ti-15Mo, and Ti-22.5Mo alloys whose deformation modes are stress-induced alpha"-martensitic transformation combined with {332}<113> twinning, {332}<113> 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}<113> twinning deformation led to a high capacity for strain hardening, which delayed the formation of adiabatic shear bands, comprising the ultra-fine beta-matrix and nano-scale omega-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.