Laser powder bed fusion of in-situ composites using dry-mixed Ti6Al4V and Si3N4 powder

Abstract

Abstract Herein, we report laser powder bed fusion (L-PBF) of dry-mixed Ti6Al4V + Si3N4 powder to create in-situ titanium matrix composites. The dry-mixed Ti6Al4V powder with 5 wt.% Si3N4 was processed using l -PBF at varying laser energy densities, between 44 and 133 J/mm3, by changing the laser scan speed (400–1200 mm/s) at constant laser power of 96 W, layer thickness of 20 μm and scan spacing of 90 μm. The selected samples were examined for microstructural evolution, in-situ reaction products and hardness. The results showed that the in-situ reaction between liquid titanium and Si3N4 forms fine TiN and Ti5Si3 reinforcements in these l -PBF processed samples. However, the irregular shape and fine size of Si3N4 reduced the feedstock flowability, and the composites could not be processed with laser energy density (E) l -PBF but further improvement is required through adjusting Si3N4 powder attributes (size, shape) and concentration.