Entropy 2016, 18(3), 102; https://doi.org/10.3390/e18030102
Development of a Refractory High Entropy Superalloy
1
Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson AFB, OH 45433, USA
2
Department of Materials Science and Engineering and Northwestern University Center for Atom-Probe Tomography, Northwestern University, 2220 Campus Drive, Evanston, IL 60208, USA
*
Author to whom correspondence should be addressed.
Academic Editor: An-Chou Yeh
Received: 12 February 2016 / Revised: 2 March 2016 / Accepted: 2 March 2016 / Published: 17 March 2016
(This article belongs to the Special Issue High-Entropy Alloys and High-Entropy-Related Materials)
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. View Full-TextKeywords:
refractory high entropy alloy; superalloy; microstructure and phase analysis; mechanical properties
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MDPI and ACS Style
Senkov, O.N.; Isheim, D.; Seidman, D.N.; Pilchak, A.L. Development of a Refractory High Entropy Superalloy. Entropy 2016, 18, 102.
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