Dual-phase Fe40Mn20Cr15Ti10Al10Ni5 high-entropy alloy prepared by mechanical alloying and spark plasma sintering: Alloying behavior, thermal stability, and mechanical properties

Abstract

The Fe-enriched high entropy alloy (HEA) shows the formation of BCC (a = 0.287 nm) and χ-phase (a = 0.889 nm) after mechanical alloying (MA) at 40 h. After spark plasma sintering (SPS) at 900 °C and 50 MPa, the dual-phase structure of FCC and BCC phases along with the χ-phase was observed. The average microhardness and elastic modulus of the SPSed sample were obtained as 5.6 ± 0.2 GPa and 131 ± 5 GPa respectively. The compressive yield strength of the SPSed sample was 1550 ± 100 MPa with ductility of ~ 11%. The dominant strengthening mechanisms are dislocation and grain boundary strengthening, which can account for ~ 65% of the observed flow stress. The correlation between the phases formed and thermal stability was correlated with different thermodynamic parameters and phase prediction by ThermoCalc software.