Abstract:The formability and the forming accuracy of materials will be greatly improved in high-velocity forming process. However, the fracture mechanism of materials in macro-micro scale keeps unknown or unclear yet. Herein, TA3 titanium alloy was adopted to investigate the fracture mechanism by Hopkinson bar test and analysis approaches of OM, SEM and stress-strain response. The results show that adiabatic shear bands (ASBs) induce the formation and the propagation of macroscale fracture, as well as softening in stress response; the fracture mechanism of TA3 titanium alloy during dynamic deformation in microscale is that spindle-shaped voids nucleate separately and then grow up to impenetrate each other, and finally micro cracks occur; the aggregation of the second-phase particles serves as the source for crack generation.