 This study examined the microstructure, phase composition, and mechanical properties of a refractory high entropy superalloy, almost 0.5 Nbeta 0.5 Tzr. It found that the alloy consisted of two distinct phases, one consisting of cuboidal nanoprecipitates aligned in rows along less than 100 type directions, and another consisting of channels between these precipitates. These phases were both coherent and had the same crystallographic orientation within the former grains. The formation of this modulated nanofase structure was attributed to nucleation and growth and spinodal decomposition mechanisms. The yield strength of this refractory high entropy superalloy was higher than that of conventional Ni-based superalloys at temperatures ranging from 20 degrees Celsius to 1,200 degrees Celsius. This article was authored by Oleg N. Senkov, Diderishyam, David N. Seidman, and others.