| Abstract Scope |
The superior mechanical properties of FCC and BCC high entropy alloys (HEAs) have offered remarkable potential for their high-temperature applications in aerospace, transportation, and energy applications. Specifically, the FCC CrMnFeCoNi HEA (Cantor alloy) family and the BCC HfNbTaTiZr HEA (Senkov alloy) family have attracted the most attention because of their synergistic strength and ductility at lower temperatures. Here, we show that the FCC Cantor alloy family loses strength quickly at elevated temperatures due to the lack of formation of hard microstructures (dense dislocation network and subgrain boundary). This can be remediated by dispersion strengthening achieved by additively manufacturing. On the other hand, we show that a BCC Senkov alloy derivative, Nb45Ta25Ti15Hf15, exhibits better creep resistance than dispersion strengthened CrCoNi. Creep deformation of this refractory high entropy alloy is controlled by dipole drag for long, straight screw locations at lower creep strain rates and jog drag at higher creep strain rates. |