X-ray tomography characterisation of lattice structures processed by Selective Electron Beam Melting

Metallic lattice structures intentionally contain open porosity; however, they can also contain unwanted closed porosity within the structural members. The entrained porosity and defects within three different geometries of Ti-6Al-4V lattices, fabricated by Selective Electron Beam Melting (SEBM), is assessed from X-ray computed tomography (CT) scans. The results suggest that horizontal struts that are built upon loose powder show particularly high (~20 × 10 −3 vol %) levels of pores, as do nodes at which many (in our case 24) struts meet. On the other hand, for struts more closely aligned (0 ◦ to 54 ◦ ) to the build direction, the fraction of porosity appears to be much lower (~0.17 × 10 −3 %) arising mainly from pores contained within the original atomised powder particles.