Development of a Refractory High Entropy Superalloy

Entropy

Adam L. Pilchak¹  Oleg N. Senkov¹  David N. Seidman²  Dieter Isheim² 

[1] Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson AFB, OH 45433, USA;Department of Materials Science and Engineering and Northwestern University Center for Atom-Probe Tomography, Northwestern University, 2220 Campus Drive, Evanston, IL 60208, USA;

关键词: refractory high entropy alloy;    superalloy;    microstructure and phase analysis;    mechanical properties;   

DOI  :  10.3390/e18030102

来源: DOAJ

【 摘 要 】

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.

【 授权许可】

Unknown