Microstructure and mechanical properties of (FeCoNi)100−x(NiAl)x eutectic multi-principal element alloys

Abstract

Eutectic multi-principal element alloys exhibit homogeneously fine microstructure, excellent castability and good industrial application prospect. In this work, the microstructure and mechanical properties of (FeCoNi)100−x(NiAl)x eutectic multi-principal element alloys are studied. The phase constitution of the studied FeCoNiAl systems is FCC+B2 NiAl-type phases. With Al concentration increasing from 11 to 28 at%, the phase constitution changes from divorced-eutectic structure with FCC being the primary phase to divorced-eutectic structure with B2 being the primary phase. The compressive yield strength of FeCoNiAl increases continuously from 201 to 899 MPa with Al content increasing from 11 to 28 at%. The improved strength can be correlated with the increased volume fraction of NiAl-type phase. Moreover, the experimental results are compared with the prediction by the Calphad method using the TTNI8 database. Finally, the stability of eutectic phases in MPEAs is discussed.