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6416 |
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Thursday, June 11, 2020, Hall D 4:40 PM Cold Gas Spraying II |
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Cold gas spraying as additive manufacturing technique: Attainable properties of high strengths materials
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Alexander List* / Helmut Schmidt University of the Federal Armed Forces, Germany Frank Gärtner / Department of Mechanical Engineering, Helmut Schmidt University - University of the Federal Armed Forces, Germany Thomas Klassen/ Department of Mechanical Engineering, Helmut Schmidt University - University of the Federal Armed Forces, Germany |
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After two decades of research, cold gas spraying is nowadays widely spread and used in many industrial applications. Besides the conventional use as a coating or repair technology, new development trends promote cold gas spraying as an additive manufacturing technique. In comparison to already established additive manufacturing methods like selective laser melting or laser metal deposition, cold gas spraying promises shorter production times due to more than an order of magnitude higher deposition rates. Moreover, reaching bulk-like properties of cold-sprayed deposits material for a variety of materials already in as-sprayed state could further reduce production steps and costs, by making time consuming post heat treatments redundant. For additive manufacturing, it is essential that the deposited material shows the performance needed in the respective application. Taking Ni and Ti-6Al-4V as examples, the present study focuses on the prediction of attainable properties of the as-deposited material as gained by cold spraying. By varying cold spray parameters as process gas pressure and temperature in combination with the use of different nozzle types, a multitude of cold gas sprayed test samples was produced and analyzed. Materials microstructure, hardness and ultimate tensile strength were determined and linked to the coating quality parameter · as the ratio between impact and critical velocity. The correlations allow for successful material property prediction. The results for cold gas spraying of Ti-6Al-4V show, that attainable materials properties still need further optimization by post spray heat treatments. In contrast, the results for cold-sprayed Ni deposits demonstrate that bulk-like material properties can be achieved in the as-deposited state by using optimum spray parameter sets. For both alloys, the applied quality parameter concept proves as valuable tool to predict coating properties or needed post spray measures, and, in general, should boost the applications of cold spraying as additive manufacturing technique. |