New materials from GE Additive Arcam help unlock potential of electron beam melting

GE Additive Arcam - D-Material Support. GE Additive

GE Additive Arcam has announced the release of development material (D-material) support for pure copper and highly alloyed tool steel during 2020. Offering new materials builds on the technology benefits of electron beam melting (EBM), such as high productivity and deep materials experience with crack-prone alloys, as well as the technology’s clean build environment, low oxidation, and low reflectivity.

The addition of pure copper and tool steel is a direct response to increased customer interest, the company reports. Offered as a general release on both pure copper and tool steel, a D-material describes the maturity of process parameters for a specific material or family of materials. D-materials meet mechanical requirements for test bars on a limited build envelope to relevant industrial standards.

Obtaining the same properties for complex geometries requires additional development, resulting in an industrialized material (I-material), with process parameters optimized for production on specific customer applications with mechanical and chemical properties.

EBM is the only commercially available technology for additive manufacturing of crack-prone alloys. Higher levels of carbon in the steel mix increase the material’s propensity to crack during production with large temperature gradients. This makes high-carbon-level steels unsuitable for AM processes with cold ambient temperatures, such as laser powder bed fusion.

Copper’s ability to absorb energy varies with the wavelength of the energy source. Pure copper absorbs 80% of the energy from an electron beam, compared to 2% of the energy from a red laser beam. The vacuum environment in which EBM operates minimizes the oxygen pickup in copper, allowing for high-conductivity copper to be produced. Oxygen reduces the conductivity of copper, while also embrittling the component.