Effect of recycled swarf and spherical Ti-6Al-4V feedstocks on laser directed energy deposition additive manufacturing

Feedstock from locally-sourced, recycled Ti-6Al-4V (Ti64) swarf is a low-cost alternative to atomized powder and encourages circular additive manufacturing. This study investigates the feasibility of Ti64 swarf as feedstock for laser directed energy deposition (L-DED) additive manufacturing. Ti64 swarf was recycled and ball-milled into irregular-shaped powder and compared to spherical plasma-atomized powder in powder flow, melt flow, and resulting microstructure. In situ monitoring showed that plasma-atomized powder had laminar flow during deposition and that ball-milled swarf powder had turbulent flow. Plasma-atomized powder caused steady melt pool dynamics and acicular microstructure. Ball-milled swarf powder caused melt pool fluctuation and equiaxed microstructure.