Jonathan W. Pegues¹, Michael A. Melia¹, Shaun Whetten¹, Nicolas Argibay¹; ¹Sandia National Laboratories

The design space offered by additive manufacturing has introduced new methods to rapidly explore the composition-properties space of multimaterial systems. Techniques, such as powder based directed energy deposition, allow for spatial compositional grading of multiple metals, such that a single specimen can consist of a wide composition range with site-specific properties. Combining this fabrication technique with high throughput characterization techniques allows for rapidly elucidating the alloy process-structure-property relationships. In this study, refractory metals were incrementally introduced to an equiatomic CoCrFeMnNi high entropy alloy to investigate the microstructure and mechanical properties evolution as a function of composition. Results show that exceptionally high hardness can be achieved for bulk material in the medium to high configurational entropy range. Hardness results are discussed in the context of the alloy configurational entropy and microstructure.SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525.