Nanoscale 3D characterization of an Al-1Fe-1Zr alloy for additive manufacturing

The Al-1Fe-1Zr alloy exploits the non-equilibrium solidification dynamics inherent to laser powder bed fusion, characterized by high thermal gradients and rapid solidification front velocities. Here, we investigate the alloy's 3D microstructure using state-of-the-art synchrotron-based nano-tomography techniques. High-resolution holographic and near-field ptychographic X-ray computed tomography were employed, achieving spatial resolutions as small as 57 nm. Our comparative analysis shows that near-field ptychographic tomography offers superior signal-to-noise ratio and spatial resolution, while holographic tomography allows for faster data acquisition with minimal loss in quality. These methods reveal the 3D distribution, morphology, and interconnectivity of Fe-rich and Zr-rich intermetallic phases. Complementary X-ray fluorescence computed tomography further provides quantitative local information on elemental wt%, revealing Fe and Zr distribution with a resolution of 0.1 wt%. The findings highlight key microstructural features that contribute to the alloy's enhanced strength and thermal conductivity, offering critical insights for optimizing its performance in LPBF applications.