Investigation of a novel additive manufacturing process for copper alloys based on the non-vacuum electron beam Technology.
Final Report Abstract
With the NVEB (None Vacuum Electron Beam) process, the electron beam (EB) can be extracted to the atmosphere to be used in additive manufacturing. Due to the beam's own energy conversion of the kinetic energy of accelerated electrons into thermal energy when they hit a metallic surface, the efficiency is very high, which brings enormous advantages, especially for the group of copper alloys. The NVEB technology also creates independence from the target size, since the working area is no longer limited by the size of the vacuum chamber. The aim of this research project was to explore the potential of NVEB for additive manufacturing of copper alloys and to use the high power (max. 25 kW) and high power density of non-vacuum electron beams for additive manufacturing based on wire as filler material. Based on NVEB's effectiveness in working with copper and copper alloys, CuSi3, CuSn6 and CuNi30Fe were chosen as the alloys for investigation. The international collaboration with the ILWT resulted in the creation of an analytical model of the additive NVEB manufacturing process for determining process parameters and predicting starting parameters. Experiments were carried out at the Institute for Materials Science at the LUH to investigate the influence of the parameters on the additive growth process and to find optimal parameters for the generation of threedimensional structures to better the analytical model. Investigations were carried out using high-speed cameras and thermocouple temperature measurements, and the modeling was improved and validated in a recurring optimization cycle. The results show a good agreement between the analytically determined process parameters and those determined in practice, so that the analytical model can be used for this process. The investigations of the additively manufactured material show that material-dependent anisotropies exist and also material-inherent properties, such as the eutectic phase formation in CuSi3, can significantly disrupt the additive manufacturing process despite optimization. It could be clearly shown both in the model and in the experiment that the supply of the filler material plays a significant role in process stabilization and that the most symmetrical possible supply in the interaction area of the EB must be selected. Likewise, a sluggish arrangement of the movement control of feed and wire feed is required in order to be able to successfully produce additively. An alloy-dependent microstructure formation can lead to anisotropic property profiles, which can be partially compensated for by targeted heat control or enhanced by targeted process control.
Publications
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Modelling of heat transfer process in non-vacuum electron beam additive manufacturing with CuSi3 alloy wire. Materials Today: Proceedings, 30, 373-379.
Mukin, Dmitrii; Valdaytseva, Ekaterina; Hassel, Thomas; Klimov, Georgii & Shalnova, Svetlana
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Non-vacuum electron beam welding and cutting of cupper. IOP Conference Series: Materials Science and Engineering, 759(1), 012003.
Hassel, T.; Beniyash, A. & Klimov, G.
