X-ray computed tomography for advanced geometrical measurements of metal powders and enhanced surface topography analyses of additively manufactured parts

Abstract

Metal powder has a significant influence on the quality and performance of laser powder bed fusion (LPBF) processes and products. A key requirement for metal powder is to have shape and size distribution designed to have adequate flowability, packing behavior and laser absorption, as well as to fabricate parts with acceptable density, surface finish and mechanical properties. Accurate three-dimensional (3D) characterizations of powder particles are fundamental to enable relevant research, for example on powder reuse and material waste reduction in LPBF. This work studies advanced measurement approaches, based on X-ray computed tomography (CT), for the 3D geometrical characterization of powder particles. The work includes comparisons with conventional powder characterization methods, considering different materials and powder morphologies. Results show the potential of the CT-based approaches to provide accurate and complete 3D powder geometrical measurements, and to exploit the obtained results for the enhancement of surface topography analyses and LPBF development. • Accurate 3D characterizations of metal powder are fundamental to improve the LPBF process. • Comparison of characterization methods for different materials and morphologies. • X-ray computed tomography enables a complete 3D geometrical characterization of powder. • CT powder characterization is exploited to enhance surface topography analyses and LPBF development.