Characterization of Si particles in additively manufactured AlSi10Mg using synchrotron transmission X-ray nanotomography

Abstract In AlSi10Mg samples manufactured by Laser Powder Bed Fusion, distinguishing the Si eutectic network/Si particles from the Al matrix by X-ray imaging is challenging due to the low absorption contrast between the Al and Si. This work investigates the possibility of overcoming this obstacle in synchrotron transmission X-ray microscopy. Effects of both different defocusing conditions and X-ray beam energies are evaluated and optimal conditions are identified for imaging a sample annealed post-print for 2h at 520°C. It is shown that both large particles (e.g. 4μm) and particles as small as 0.5 μm, can be imaged with reasonable precision in 3D non-destructively.