Electron beam powder bed fusion of copper components: a review of mechanical properties and research opportunities

The purpose of this work is to identify the principle of electron beam powder bed fusion (EB-PBF) and the performance of this AM method in the processing of copper components. This review details the experimentally reported properties, including microstructural, mechanical and physical properties of pure copper made by EB-PBF. The technical challenges and opportunities of EB-PBF are identified to provide insight into the influence of process parameters on observed mechanical properties as well as a roadmap for strategic research opportunities in this field. These insights allow optimisation of EB-PBF parameters, as well as comparison of the relative merits of EB-PBF over LB-PBF in the processing of copper components. This review details the microstructure and mechanical properties of EB-PBF of copper and identifies the technical opportunities and challenges. In addition, this report characterises the influence of process parameters, and subsequent energy density, on the associated mechanical properties. The discussions showed that the chance of pollution in copper processing by EB-PBF is less than laser-based powder bed fusion (LB-PBF) due to the high vacuum environment for electron beam. Oxygen content in the EB-PBF of copper powder is a vital factor and significantly affects the mechanical properties and quality of the specimen including physical density. The produced Cu2O due to the existence of oxygen content (in powder and bulk material) can improve the mechanical properties. However, if the Cu2O exceeds a certain percentage (0.0235%wt), cracks appear and negatively affect the mechanical properties. In copper printing by this method, the process parameters have to be tuned in such a way as to generate low build temperatures due to the high thermal conductivity of this alloy and the high sintering tendency of the powder.