Development of a Refractory High Entropy Superalloy

作者：Senkov, Oleg N.^*; Isheim, Dieter; Seidman, David N.; Pilchak, Adam L.

来源：Entropy, 2016, 18(3): 102.

DOI：10.3390/e18030102

• refractory high entropy alloy
• superalloy
• microstructure and phase analysis
• mechanical properties

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 a(1) = 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 a(2) = 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 degrees C to 1200 degrees C.

• 出版日期2016-3
• 单位西北大学