Effect of Defects on the Mechanical Properties of Laser Powder Bed Fused Ti-6Al-4V

Abstract

Process-induced volumetric defects are inherent to additively manufactured parts. This study investigates the effect of volumetric defects on the tensile properties of the laser powder bed fused (L- PBF) Ti-6Al-4V specimens fabricated with large variations in process parameters (a total of six sets of process parameters). Cylindrical rods of L-PBF Ti-6Al-4V specimens were stress-relieved before removal from plates and machined to tensile specimens. The defect distribution of specimens resulting from each set of process parameters was analyzed using a high-resolution X-ray computed tomography machine. Quasi-static tensile tests were performed at room temperature using a servo-hydraulic MTS machine. Tensile results were correlated with defect statistics. No apparent difference was observed in the yield strength of the L-PBF Ti-6Al-4V specimens despite the large variations in the process parameters resulting in significant differences in defect content. However, a considerable drop in ductility was observed for the specimens fabricated with insufficient energy.