Ti-6Al-4V powder reuse in laser powder bed fusion (L-PBF): The effect on porosity, microstructure, and mechanical behavior

• Powder reuse effects on mechanical properties of L -PBF Ti64 were investigated. • Location effects; i.e., upstream and downstream of shield gas flow, were studied. • More and larger defects were formed in downstream locations due to spattering. • Powder reuse slightly increased strength and reduced ductility due to O pickup. • Fatigue resistance in the upstream locations improved with limited powder reuse. This work investigated the effects of powder reuse, and location dependency on the mechanical properties of plasma atomized Ti-6Al-4V Grade 5 parts manufactured via laser powder bed fusion ( L -PBF). Reusing the powder enhanced powder flowability and packing state while increasing the oxygen. Fatigue performance improved with limited reuse for the specimens upstream of the shield gas and decreased at downstream locations due to large critical defects. Powder reuse increased tensile strength and the critical energy release rate under high strain-rate loading. The specimens in downstream locations suffered more from spattering, resulting in lower fatigue performance and tensile ductility.