Effects of Powder Reuse and Spatial Location Dependency on the Powder Characteristics and Defect Structure of Additively Manufactured Ti-6Al-4V Parts

In laser powder bed fusion additive manufacturing (L-PBF AM), different powder characteristics including particle size and morphology may yield different packing states and thus different defect content in the resulting parts. As the powder is spread by the recoater, the packing state may not be uniform on the powder bed, giving rise to location-dependent part performance. In addition, as the powder is reused (a common practice in AM industry), its characteristics continuously evolve, causing the defect content to change from build to build. This study aims to investigate the effects of powder reuse and part location on powder characteristics as well as the defect structure of the parts. Results indicate powder reuse in an L-PBF system may reduce the number of defects in the as-fabricated parts due to the superior packing state of reused powder. Part density was also found to be location-dependent, with more defects near the gas outlet.