Influence of additive manufacturing process on the impact strength of Ti-6Al-4V

Understanding the role of process-related defects on material strength is of critical importance for developing safe and affordable acceptance criteria for additively manufactured components. Testing at high strain rates can reveal much more about the effect of defects on the fracture resistance of the material. In this work, material response and ductility of wrought and additive manufactured Ti-6Al-4V, fabricated by selective laser melting (SLM) and sintering (SLS), under uniaxial and multiaxial stress state, were characterized at low and high strain rates. Taylor cylinder impact tests were performed to determine the velocity at onset damage development. Despite small differences in the uniaxial response, results show that SLS and SLM fractured at impact velocity 60% and 20% lower than that of wrought. Microscopy investigation revealed that the presence of voids reduces the shear resistance anticipating the formation of shear bands.