Laser Metal Deposition of Ti-6Al-4V with a Direct Diode Laser Set-up and Coaxial Material Feed

Abstract

The production of components from the titanium alloy Ti-6Al-4V is of great importance for many industrial fields, especially for the aerospace industry. Laser metal deposition (LMD) processes can be used either for manufacturing of components or repair. The majority of LMD set-ups use a concentrical laser and a powder feed through nozzles focusing the powder on a spot. Gas shielding is problematic in such set-ups, which hence require the use of protective gas chambers. The present paper details results on laser metal deposition (LMD) of Ti-6Al-4V with a new direct diode laser head. In the LMD set-up, six 200W laser diodes are positioned on a circle around the feeding lance and create a laser spot with a diameter of ~0.9 mm. The laser beam is thus directly generated inside the head. The set-up allows for co-axial feed of powder or wire material. Due to the arrangement of the single laser beams and the coaxial filler material feeding, a direction independent welding process is possible. The Ti-6Al-4V specimens deposited with the LMD head show a clean surface and a dense microstructure. The results indicate that the new diode laser head allows for a direction-independent LMD process with low oxygen take-up.