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The Additive Manufacturing technology Electron Beam Melting shows high potential in processing pure copper for high conductivity applications. Pure copper powder was consolidated, and process parameters were optimized. It is feasible to manufacture components with a relative density >99.5 %, an electrical conductivity >57 MS/m, an ultimate tensile strength >175 MPa and with an elongation at fraction of >35 %. With those physical properties, high performance applications like heat exchangers, induction coils and electrification components can be additively manufactured with EBM.

Additive manufacturing by selective electron beam melting (SEBM) was used to fabricate pure copper specimens. A process window at process temperature of 530 °C, gives the required beam powers and deflection speeds for manufacturing dense specimens (>99.5%). The microstructure of SEBM specimens was analyzed by using optical and scanning electron microscopy (SEM). Electrical conductivity, thermal conductivity, hardness, and mechanical performance were investigated by using eddy current, laser flash analysis, Vickers hardness and tensile tests, respectively. It was found that the variation of beam power and scan speed results in different microstructures from columnar to nearly equiaxed grain. The electrical conductivity of SEBM-processed specimens was above 58 MS/m (>100 IACS) while their hardness was around 55 HV0.05 and 46 HV5 without any dependency on processing parameters within the process window. The tensile tests revealed how vertical cracks affect the mechanical strength under tensile loading condition. The results of this study not only show a reliable process window but also introduce the links between processing parameters, defect formations, conductivity and mechanical strength of pure copper specimens manufactured by SEBM.

Additive manufacturing by selective electron beam melting (SEBM) was used to process a powder mixture consisting of elemental copper and chromium powders (nominal composition: Cu-25Cr). The melting temperatures of copper and chromium are largely different. As a result, the copper particles start melting while the chromium ones are still solid. Eventually, also the chromium particles get molten since the local temperatures during SEBM are rather high. The microstructure was analyzed by scanning electron microscopy (SEM) and focused ion beam (FIB)-SEM. It was observed that ultra-fine Cr particles are formed and distributed in the Cu matrix due to the fast cooling rate and subsequent spinodal decomposition.

This paper investigates the physical properties of 99.91% pure copper produced by Additive Manufacturing via selective electron beam melting (SEBM). Eddy current measurements and laser flash analyses are used to determine the electrical and the thermal conductivity. Electrical and thermal conductivity follow the Wiedemann-Franz law. The correlation of conductivities and porosity shows that 99.95 % dense components with nearly optimal conductivities (σ = 55.82 MS m–1 and λ = 400.1 W m–1 K–1) can be fabricated with SEBM. The small deviation from the theoretical maximum of copper (59.7 MS m–1) can be explained by the characteristics of the raw material and chemical impurities.

Additive Manufacturing using Selective Electron Beam Melting is attractive to fabricate pure copper components due to the specific properties of the electron beam. In this contribution, two different copper powder batches with different oxygen levels are processed. The samples produced using the powder with high oxygen level show cracks, whereas samples from the powder with low oxygen content are crack-free. The mechanical properties of the crack-free samples are investigated and compared to wrought and annealed copper.

The additive processing of 99.94% pure copper powder via selective electron beam melting (SEBM) is presented. The high thermal and electrical conductivity of pure copper combined with the freedom in design in additive manufacturing is promising for future application e.g. as heat exchanger. A process window for the generation of dense copper parts could be evaluated. Despite the high thermal conductivity, comparatively low build temperatures have to be used due to the high sintering tendency of the powder. The latter also limits the maximum power input during melting.