Ti-containing High-Entropy Alloys for Aeroengine Turbine Applications

Abstract

Sustained research in high-entropy alloys (HEAs) has presented opportunities for relatively lighter alloys, specifically the Ti-containing HEAs, having an excellent combination of properties, and a great potential to replace heavier superalloys. We adopted a novel data-driven methodology to sort and select Ti-containing HEAs from the literature for their potential applications in aeroengine turbines by applying multiple-attribute decision-making (MADM). The ranks of the alloys evaluated by diverse MADMs were consistent. The data-driven methodology identified the following top five Ti-containing HEAs: ONS-BCC-Ti17.8 (Al20.4-Mo10.5-Nb22.4-Ta10.1-Ti17.8-Zr18.8), EF-BCC-Cr20-Ti20 (Ti20-Zr20-Hf20Nb20-Cr20), ONS-BCC-Ti27.9 (Al11.3-Nb22.3-Ta13.1-Ti27.9-V4.5-Zr20.9), ONS-BCC-Ti27.7 (Al5.2-Nb23.4Ta13.2-Ti27.7-V4.3-Zr26.2), and ONS-BCC-Ti20 (Nb20-Cr20-Mo10-Ta10-Ti20-Zr20); the methodology provides directives for further development of the identified Ti-containing HEAs for potential replacement of legacy superalloys in aeroengine turbines. The top-ranked alloy (Al20.4-Mo10.5-Nb22.4-Ta10.1-Ti17.8-Zr18.8) is lighter than the current industry benchmark, Inconel 718, by ~13%. All the top five Ti-containing HEAs have configurational entropy greater than ~13.3 J/mol K and body-center cubic crystal structure. The potency of the methodology could further be tapped by choosing appropriate weights of the properties for specific aeroengine turbine applications.