TY - JOUR A1 - Laquai, René A1 - Müller, Bernd R. A1 - Kasperovich, G. A1 - Haubrich, J. A1 - Requena, G. A1 - Bruno, Giovanni T1 - X-ray refraction distinguishes unprocessed powder from empty pores in selective laser melting Ti-6Al-4V T2 - Materials Research Letters N2 - For the first time, X-ray refraction techniques are proven for the identification of void formation in Ti-6Al-4V parts produced by selective laser melting. The topology and volume fraction of pores are measured in samples produced with different laser energy density. Unique X-ray refraction methods identify different kinds of defects, characteristic to the regions below and above the Optimum laser energy density, namely unprocessed powder (unmolten powder particles, balling effect, and Fusion defects) from empty keyhole pores. Furthermore, it is possible to detect small inhomogeneities (voids or cracks) with sizes below the spatial resolution of optical microscopy and X-ray computed tomography. PB - Taylor & Francis Group CY - London, UK KW - Additive manufacturing KW - X-ray refraction KW - Microscopy KW - X-ray computed tomography KW - Porosity PY - 2018 UR - https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/43404 AN - OPUS4-43404 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-434041 SN - 2166-3831 VL - 6 IS - 2 SP - 130 EP - 135 AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany