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Pore Formation Driven by Particle Impact in Laser, Powder-blown Directed Energy Deposition



Edward Garboczi, Newell Moser, Samantha Webster, Kornel Ehmann, Jian Cao, Kamel Fezzaa, Tao Sun


Material manufactured by laser, powder-blown directed energy deposition often contains residual pores, which can be detrimental to the strength and fatigue life of a part. We uncover a new kind of pore formation that is driven by powder particle impact, not energy transfer, where vapor is entrapped beneath an impacting powder particle through air-cushioning. This phenomenon stands in stark contrast to currently accepted pore formation mechanisms, such as keyholing and lack of fusion, which are addressed by modulating energy transferred to the material. We show that powder particle diameter and velocity play an important role in vapor entrapment and demonstrate the significance of entrapped vapor pores via X-ray computed tomography. By controlling powder particle impact, it is possible to manufacture higher quality materials through laser, powder-blown directed energy deposition.
PNAS Nexus


additive manufacturing, directed energy deposition, pore formation, vapor entrapment, synchrotron imaging, tomography


Garboczi, E. , Moser, N. , Webster, S. , Ehmann, K. , Cao, J. , Fezzaa, K. and Sun, T. (2023), Pore Formation Driven by Particle Impact in Laser, Powder-blown Directed Energy Deposition, PNAS Nexus, [online],, (Accessed June 20, 2024)


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Created May 26, 2023, Updated September 20, 2023