Innovative Processing of Compacted Waste Aluminum Alloy Powders via Controlled Remelting and Solidification

This work addresses the challenges of recycling and processing atomized AlSi10Mg alloy powder batches, which are often unsuitable for LPBF (laser powder bed fusion) due to size and surface oxidation issues. These factors hinder melting and lead to waste, raising economic and environmental concerns. The aim is to recycle this powder through powder metallurgy (P/M), using compaction at different pressures and arc remelting followed by suction casting using a stepped Cu‐mold so that the effect of different cooling rates could be investigated. The alloy powder has been evaluated in terms of its D ₅₀ , morphology, elemental distribution, and composition after the most commercially relevant sieved range 32–75 μm has been excluded from the total volume produced by gas atomization. Therefore, the study focused primarily on powder fractions that are largely out of specification for LPBF. The compacts are also examined through the analysis of the compaction curve, while the alloy solidification was discussed based on CALPHAD and differential scanning calorimetry results. The microstructural characterization of the remelted compacts focuses on dendritic spacing and pores fraction, density, and size, relating them to the cooling rates and compaction loads (loads of 30 kN, 50 kN, 80 kN, and 100 kN). Such highly innovative approach revealed that intermediate compaction loads (50–80 kN) combined with higher cooling rates yield refined microstructures, reduce porosity, and enhance microhardness in remelted AlSi10Mg compacts. Excessive compaction (100 kN), in contrast, led to increased porosity and reduced microhardness, emphasizing the need for optimized pressure‐cooling combinations to maximize the mechanical performance of recycled waste Al powders.