Dynamic Fracture of Ti-5553 Alloy in Taylor Impact Test

摘要

The dynamic fracture behavior of a new near-beta Ti-5Al-5Mo-5V-3Cr^(-1)Fe(Ti-5553)alloy under a high strain rate loading was investigated systemically using the Taylor impact test,over the impact velocity ranging from156 ms^(-1) to 256 ms^(-1).An optical microscope(OM)and a scanning electron 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 anα+βduplex microstructure including more primaryαphase,while the velocity is 234 ms^(-1) for the alloy with a duplex microstructure including less primaryα phase.From the impact fracture morphologies,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 primaryαphase were more than that with less primaryαphase.Compared to the duplex microstructure with less primaryα phase,Ti-5553 alloy with more primaryαphase exhibited a better capability to resist an adiabatic shear damage.