Mapping Spatial Distribution of Pores in an Additively Manufactured Gold Alloy Using Neutron Microtomography

Abstract

A crucial criterion for the quality of the additively manufactured parts is the porosity content for achieving an acceptable final relative density. In addition, for jewelry applications, visible pores are unacceptable at or in the vicinity of the surface. In this study, non-destructive 3D neutron microtomography is applied to map the spatial distribution of pores in additively manufactured red-gold samples. The 3D imaging assessment underlines the high relative density of the printed red-gold sample and indicates residual pore sizes are predominantly below the limit of concern for jewelry applications. The 3D maps of pores within printed samples highlight the effect of the scanning strategy on the final quality and location of pores in the printed samples. These results confirm that neutron microtomography is a novel and precise tool to characterize residual porosity in additively manufactured gold alloys and other higher-Z materials where such investigation using other non-destructive methods (such as X-rays) is challenging due to the limited penetration depth.