Processing Effects on O and H in Ta Powder for Metal Additive Manufacturing

Lyon, Ashton

Etd

Processing Effects on O and H in Ta Powder for Metal Additive Manufacturing

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Experimenting with using refractory metals in powder-based additive manufacturing (AM) such as tantalum and tungsten, known for their heat and wear resistance, has been an emerging topic in the energy, aerospace, and medical industries. Recent research has demonstrated the need for high-quality feedstock powder to maintain the desired mechanical properties of parts produced by powder-based methods such as powder bed fusion, cold spray deposition, and directed energy deposition. Oxygen and hydrogen impurities may have significant impacts on powder behavior, and thus final mechanical properties, of metal AM parts. This work investigates a range of atmospheric and heat treatment processing conditions to reliably control the O and H content in Ta powder. Ta powder was treated using a rotary vacuum tube furnace in a selection of atmospheres and temperatures and characterized with an inert gas fusion ONH detector, moisture content analyzer, and particle compression tester, finding combinations of processing conditions yielding varying levels of O and H impurities. With this foundation, further research may begin establishing a relationship between O and H content in Ta powders with powder behavior, and finally, a finished part’s mechanical properties.

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