Ti-containing High-Entropy Alloys for Aeroengine Turbine Applications

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 (Al 20.4 -Mo 10.5 -Nb 22.4 -Ta 10.1 -Ti 17.8 -Zr 18.8 ), EF-BCC-Cr20-Ti20 (Ti 20 -Zr 20 -Hf 20 - Nb 20 -Cr 20 ), ONS-BCC-Ti27.9 (Al 11.3 -Nb 22.3 -Ta 13.1 -Ti 27.9 -V 4.5 -Zr 20.9 ), ONS-BCC-Ti27.7 (Al 5.2 -Nb 23.4 - Ta 13.2 -Ti 27.7 -V 4.3 -Zr 26.2 ), and ONS-BCC-Ti20 (Nb 20 -Cr 20 -Mo 10 -Ta 10 -Ti 20 -Zr 20 ); 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 (Al 20.4 -Mo 10.5 -Nb 22.4 -Ta 10.1 -Ti 17.8 -Zr 18.8 ) 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.