Laser additive manufacture of titanium alloys

Titanium alloys are highly adaptive to the manufacture of military, aircraft and medical devices due to their high tensile strength and toughness. However, the traditional processing path of titanium alloys are difficult and costly, which restricted the wide applications of titanium alloys. Additive manufacture has provided new processing routings for titanium alloys, with which high qualified components can be produced efficiently. Selective laser melting and laser metal deposition are two frequently used processing routings for additive manufacture of titanium alloys; while the former is powder bed based and can be used to produce fine components, the latter is powder feeding based and can be utilised to produce large components. With different forming mechanisms, the processing routings exhibit different characteristics in forming capacities, surface roughness, inner microstructures and mechanical properties, during their applications on titanium alloys. The development, characteristics and the applications of these two techniques in titanium alloys are reviewed, and the future developments of laser additive manufacture of titanium alloys are also discussed.