Impact toughness of Ti–6Al–4V parts fabricated by additive manufacturing

Additive manufacturing is a new and quite promising trend in the low-cost building of Ti–6Al–4V parts which are widely used in aircraft, chemical, medical, and other industries. It is well-documented that 3D-printed Ti–6Al–4V parts have higher yield strength, ultimate tensile strength and hardness but lower ductility and toughness as compared with wrought alloy. In this study, comparison on the microstructure and impact toughness of wrought Ti–6Al–4V and ones fabricated by additive manufacturing such as i) laser and electron-beam powder bed deposition as well as ii) direct energy wire deposition was performed. The 2.7 times enhancement of fracture toughness of Ti–6Al–4V parts fabricated by electron beam free-form fabrication as compared with cast Ti–6Al–4V alloy was demonstrated. The 5.6 times increase in the impact toughness as in contrast with selective laser and electron-beam melted ones was revealed.