Laser directed energy deposition of the refractory compositionally complex alloy TMT-8Cr–10Al: Processability, microstructural evolution and phase formation

Refractory compositionally complex alloys (RCCAs) represent a promising class of materials that extend the concept of high-entropy alloys (HEAs) by incorporating high-melting-point refractory elements. To date, the production of RCCAs has been limited to laboratory scale, with quantities insufficient for industrial application. In the present study, the RCCA TMT-8Cr–10Al was processed through laser directed energy deposition (DED-LB/M), a more flexible alternative to traditional, lab scale methods such as repetitive arc melting. Samples were successfully synthesized and further characterized in terms of deposition quality, microstructure, chemical and phase composition, and mechanical hardness. The fabricated samples show porosity levels as low as 0.3 % and hardness values up to 1000 HV1. In addition to the widespread presence of intermetallic phases, a notable deviation from the expected body-centered cubic (BCC) structure toward a hexagonal-close-packed (HCP) structure is observed at laser powers of 800 W and 1200 W. The microstructure exhibits largely non-directional, dendritic, equiaxed grains. Altogether, these findings confirm the feasibility of producing TMT-8Cr–10Al by DED and provide a solid basis for future efforts aimed at scaling up processing and optimizing the mechanical performance of RCCAs.