The influence of heat treatment on precipitate formation in Scalmalloy®: In-situ X-ray diffraction investigation

Additive manufacturing offers a novel approach to producing lightweight components with complex geometries.Aluminum alloys, renowned for their low density and high mechanical properties, have emerged as primecandidates for this technology. Aluminum alloys, processed using laser-based powder bed fusion (PBF-LB), havegained significant interest in aerospace, construction, and automotive applications due to their lightweightproperties, corrosion resistance, and fine-grained microstructure. Given its recent attention, PBF-LB Scalmalloy®samples were subjected to in-situ coupled experiments with heat treatments in a high-energy X-ray diffraction(HEXRD) beamline to collect diffractograms in transmission mode. Subsequently, transmission electron microscopy(TEM) was used to analyze the microstructure deeply and pursue the characterization of the formedprecipitates. Results showed finely dispersed precipitates formed, which evolved slowly in lower heat-treatmenttemperatures, under 325 ◦C. In contrast, a higher temperature of 400 ◦C led to coarsening and hardness loss forlong treatment periods.