Dynamic Fracture of Ti-5553 Alloy in Taylor Impact Test

The dynamic fracture behavior of a new near-beta Ti-5Al-5Mo-5V-3Cr-1Fe (Ti-5553) alloy under a high strain rate loading was investigated systemically using the Taylor impact test,over the impact velocity ranging from 156 ms^-1 to 256 ms^-1.An optical microscope (OM) and a scanning e-lectron microscope (SEM) were used to characterize the microstructure evolution.The experimental results have demonstrated that the velocity from deformation to fracture is 256 ms^-1 for the alloy with an α+β duplex microstructure including more primary α phase,while the velocity is 234 ms^-1 for the alloy with a duplex microstructure including less primary α phase.From the impact fracture mor-phologies,smooth and smeared surfaces and ductile dimple areas can be observed.The failure mode of the titanium alloy with both microstructures is adiabatic shear banding.According to the fracture analysis,the ductile fracture area with the dimple area in the alloy with much more primary α phase were more than that with less primary α phase.Compared to the duplex microstructure with less pri-mary α phase,Ti-5553 alloy with more primary α phase exhibited a better capability to resist an adia-batic shear damage.