Toward novel AM feedstocks: Ultrasonically atomized 7075 and Al–Zn–Mg–Cu–Co–Cr–Mo powders

Powder characteristics critically influence laser absorption, melt pool dynamics, and defect formation in melting-based additive manufacturing (MAM). As such, the development of highly spherical, flowable powders is essential to improve processing stability and part quality. Ultrasonic atomization (UA) has demonstrated strong potential for producing powders with refined morphology. Despite this capability, its application to Al–Zn–Mg–Cu alloys, especially through induction-based UA systems, has not been systematically examined. This study investigates the induction-based ultrasonic atomization of 7075 aluminum powders and evaluates CoCrMo addition as a sustainability-driven compositional modification employing recycled metallic residues from MAM processes. Morphological analysis confirmed that both pure and modified powders exhibited excellent sphericity (mean = 0.97), roundness (0.89), and ellipticity (1.13). Flowability testing indicated favorable behavior, with an angle of repose of approximately 25.05°, a Hausner ratio of 1.068 ± 0.012, and a Carr's index of 6.43 ± 1.07. The CoCrMo-modified alloy exhibited lamellar Al₉Co₂ and blocky Al₄₅Cr₇ intermetallics evidencing effective solute incorporation within the Al matrix. Thermal analysis indicated distinct solid-state transformation behavior in the modified alloy, consistent with Scheil solidification predictions. These findings demonstrate that UA enables the fabrication of recyclable, compositionally tailored aluminum alloy feedstocks with superior morphology and flow characteristics underscoring their potential for advanced AM applications.