About this Abstract |
Meeting |
MS&T24: Materials Science & Technology
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Symposium
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Additive Manufacturing of Metals: Microstructure, Properties and Alloy Development
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Presentation Title |
Refractory Metal Mixing in Directed Energy Deposition - Experiments and Analysis |
Author(s) |
Anthony Stair, Alexander Myers, Jonathan Malen, Bryan Webler, Jack Beuth, Maarten de Boer |
On-Site Speaker (Planned) |
Anthony Stair |
Abstract Scope |
With their high melting temperatures, refractory metals are of great interest in high temperature applications. However, their density is high. To reduce their effective density, we select niobium (Nb), which has a density approximately one half of other refractories, as a major constituent in a tantalum (Ta) alloy. An advantage of this system is that the ductile-to-brittle transition temperature is well below room temperature, which lowers the propensity for cracking. Using DED and analyzing with SEM backscatter imaging and electron dispersive spectroscopy, we observe that Nb powder on a Ta baseplate mixes well and that the melt pool interface is smooth. In the reverse situation Ta- and Nb- rich bands are prevalent, and the interface is rough. Mixing is then improved by increasing the energy input per unit length. We are conducting real-time melt pool thermal imaging using a two color technique and Flow3D simulations to understand these phenomena. |