Manufacturing and characterization of in-situ alloyed Ti6Al4V(ELI)-3 at.% Cu by laser powder bed fusion

Biofunctionalization of Ti6Al4V alloy with metallic agents like Ag or Cu is a promising approach to add antibacterialproperties and thus to reduce the risk of implant failure. This research investigates the in-situ alloying ofTi6Al4V(ELI) with 3 at.% Cu powders using Laser Powder Bed Fusion (L-PBF). The morphology and geometricalcharacteristics of the single tracks and layers were studied. Laser powers of 170W and 340 W, and scanningspeeds ranging from 0.4 to 1.4 m/s and 0.8–2.8 m/s were implemented. Single track results showed balling effectand humping at high scanning speeds, 1.4 m/s and 1.6 m/s, for each laser powder respectively. Conversely,keyhole formation occurred at lower scanning speeds of 0.4–0.6 m/s for 170W laser power, and below and0.8 m/s for 340W laser power. For both laser powers, single layers resulted in smoother surfaces at lowerscanning speeds. These results were used for the development of optimal process parameters for 3D cubes with99.9 % density. Optimal process parameters were found for 170W and 340W laser powders at 0.7−0.9 and1.0–1.2 m/s scanning speeds, respectively.In-situ alloying by L-PBF was challenging and a homogeneous distribution of Cu within the alloy was hard toachieve. The increase in laser power from 170 to 340W resulted in small increase in homogenization.Microstructural analyses after stress-relieving treatment showed the presence of α’ and β phases, as well as CuTi2intermetallic precipitates. The finer microstructure together with CuTi2 intermetallic precipitates resulted in anincrease in hardness. This study demonstrates the potential for printing in-situ alloyed Ti6Al4V(ELI)- 3 at.% Cufor biomedical applications. However, further studies are required to determine the effectiveness of antibacterialproperties.