Microstructural evolution and mechanical behaviour of laser welding Ti6Al4V fabricated by laser powder bed fusion and direct energy deposition

Abstract

Laser powder bed fusion (LPBF) and directed energy deposition (DED) are two typical additive manufacturing technologies. LPBF is relatively slow and suitable for printing small and complex parts, while DED can print larger parts at a faster speed. Therefore, welding them together maximises the advantages of both technologies. In this study, laser welding technology was applied to join 5 mm thick Ti6Al4V samples fabricated using LPBF and DED processes. Results showed that anisotropy in grain morphology of the base material affected the size of acicular α’ martensite and texture strength. The welded joints showed good tensile properties, with the average ultimate tensile strength (∼1105 MPa).