Manufacturability of CoCrFeNiMnzAlxCuy High Entropy Alloy by Laser Powder Bed Fusion

Six pre-alloyed high entropy alloys powders from the CoCrFeNiMnzAlxCuy family were used to manufacture samples through Laser Powder Bed Fusion technology. These samples were used to assess the manufacturability, microstructure and mechanical properties of the developed alloys. It was found that increasing the Al concentration promoted the formation of a BCC/B2 phase, increasing the hardness and having a direct positive impact on the tensile properties. However, adding more aluminium than what can be found in the Al0.5CoCrFeNi alloy led to extensive manufacturability issues that hindered the tensile properties. On the other hand, the Cu concentration did not appear to yield any significant impact on the microstructures and mechanical properties of the alloys. The considered additively manufactured alloys presented an overall higher hardness than their conventionally manufactured counterparts, but a lower ductility. Thermal treatment led to the precipitation of a σ phase in Al-containing HEAs, and of a secondary FCC phase in Cu-containing alloys. Finally, this paper proves the potential of the CoCrFeNiAlx alloy family compared to single-phase stainless steels such as 316L and two-phase stainless steels such as SAF 2507.