Unique precipitations in a novel refractory Nb-Mo-Ti-Co high-entropy superalloy

Abstract

Herein, a novel refractory Nb₃₀Mo₃₀Ti₂₀Co₂₀ (at. %) high-entropy superalloy (RHESA) is introduced. Annealing at 1200 °C led to the precipitation of a semi-coherent individual (Co, Ti)-rich B2, (Ti, O)- rich fcc (Ti-rich oxides), and hierarchical B2+fcc nanoparticles in the (Nb, Mo)-rich RHESA bcc phase. B2+fcc dispersoids were dominant, and they nucleated heterogeneously because of the coherency ensured by the Baker-Nutting orientation relationship