Powder Degradation and Recycling Strategies for Aluminum Alloys in Additive Manufacturing: A Comprehensive Review

The growing adoption of additive manufacturing (AM) has increased the demand for efficient and sustainable powder management, particularly for aluminum alloys used in lightweight and high-performance applications. Despite their attractive strength-to-weight ratio, corrosion resistance, and recyclability, aluminum powders are highly sensitive to degradation during repeated reuse. This review examines the main physical and chemical changes occurring in aluminum alloy powders during AM, including oxidation, morphological evolution, agglomeration, moisture uptake, contamination, and porosity-related effects. Their influence on powder flowability, spreadability, packing behavior, laser absorption, and final part quality is critically discussed. The study also reviews current and emerging powder recycling and reconditioning strategies, including sieving, top-up blending, Hydride–Dehydride processing, plasma spheroidization, annealing, and chemical surface treatments. In addition, best practices for powder handling, storage, and quality assessment are summarized to support reliable reuse. Particular attention is given to aluminum powders used in laser powder bed fusion. Unlike earlier reviews that address powder degradation, recycling, or aluminum AM separately, this review provides an integrated framework connecting degradation mechanisms, reconditioning strategies, and qualification methods for reused aluminum powders. It also highlights key knowledge gaps and future directions for developing more reliable and sustainable powder lifecycle management in aluminum-based AM.