Development of a refractory high entropy superalloy

Oleg N. Senkov*, Dieter Isheim, David N. Seidman, Adam L. Pilchak

*Corresponding author for this work

Research output: Contribution to journalArticle

67 Scopus citations

Abstract

Microstructure, phase composition and mechanical properties of a refractory high entropy superalloy, AlMo0.5NbTa0.5TiZr, are reported in this work. The alloy consists of a nano-scale mixture of two phases produced by the decomposition from a high temperature body-centered cubic (BCC) phase. The first phase is present in the form of cuboidal-shaped nano-precipitates aligned in rows along < 100 > -type directions, has a disordered BCC crystal structure with the lattice parameter a1 = 326.9 ± 0.5 pm and is rich in Mo, Nb and Ta. The second phase is present in the form of channels between the cuboidal nano-precipitates, has an ordered B2 crystal structure with the lattice parameter a2 = 330.4 ± 0.5 pm and is rich in Al, Ti and Zr. Both phases are coherent and have the same crystallographic orientation within the former grains. The formation of this modulated nano-phase structure is discussed in the framework of nucleation-and-growth and spinodal decomposition mechanisms. The yield strength of this refractory high entropy superalloy is superior to the yield strength of Ni-based superalloys in the temperature range of 20 °C to 1200 °C.

Original languageEnglish (US)
Article number102
JournalEntropy
Volume18
Issue number3
DOIs
StatePublished - Mar 1 2016

Keywords

  • Mechanical properties
  • Microstructure and phase analysis
  • Refractory high entropy alloy
  • Superalloy

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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