The outstanding tensile strength of Ni-rich high entropy superalloy fabricated by powder metallurgical process

Abstract

The present work reports the microstructure and tensile properties of a Ni-rich high-entropy superalloy (HESA; Ni46Co22Al12Cr8Fe8Ti3Mo1) having outstanding tensile properties, including yield strength of 1355 MPa and fracture elongation of 8.7%. Powder metallurgical (PM) processes were used to fabricate the present HESA with homogeneous and fine-grained microstructure. A large number of gamma' precipitates were homogeneously distributed in a face-centered cubic (FCC) matrix. By using PM processes, a nanoscale grain size was achieved, and ultrafine TiC and Al2O3 dispersoids were uniformly formed within the FCC matrix. The outstanding mechanical properties of the HESA were attributed to the combined effect of grain boundary strengthening, solid solution strengthening, precipitate formation and dispersion strengthening.