npj Computational Materials (Aug 2023)

Design of refractory multi-principal-element alloys for high-temperature applications

  • Gaoyuan Ouyang,
  • Prashant Singh,
  • Ranran Su,
  • Duane D. Johnson,
  • Matthew J. Kramer,
  • John H. Perepezko,
  • Oleg N. Senkov,
  • Daniel Miracle,
  • Jun Cui

DOI
https://doi.org/10.1038/s41524-023-01095-4
Journal volume & issue
Vol. 9, no. 1
pp. 1 – 10

Abstract

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Abstract Refractory multi-principal-element alloys (RMPEAs) exhibit high specific strength at elevated temperatures (T). However, current RMPEAs lack a balance of room-temperature (RT) ductility, high-T strength, and high-T creep resistance. Using density-functional theory methods, we scanned composition space using four criteria: (1) formation energies for operational stability: $$-150\le {E}_{{\rm {f}}}$$ − 150 ≤ E f ≤ +70 meV per atom; (2) higher strength found via interstitial electron density with Young’s moduli E > 250 GPa; (3) inverse Pugh ratio for ductility: G/B 2500 °C. Using rapid bulk alloy synthesis and characterization, we validated theory and down-selected promising alloy compositions and discovered Mo72.3W12.8Ta10.0Ti2.5Zr2.5 having well-balanced RT and high-T mechanical properties. This alloy has comparable high-T compressive strength to well-known MoNbTaW but is more ductile and more creep resistant. It is also superior to a commercial Mo-based refractory alloy and a nickel-based superalloy (Haynes-282) with improved high-T tensile strength and creep resistance.