On the correlation between L12 nanoparticles and mechanical properties of (NiCo)52+2x(AlTi)4+2xFe29-4xCr15 (x=0-4) high-entropy alloys.

Different L1 2 -Ni 3 (Ti, Al) phase contents in (NiCo) 52+2x (AlTi) 4+2x Fe 29-4x Cr 15 (x = 0-4) high-entropy alloys are designed based on CALPHAD and its effects on mechanical properties are systematically studied. Results show that excellent combination of yield strength (635-753 MPa), ultimate tensile strength (1010-1074 MPa), and fracture strain (23-31%) could be obtained for high-entropy alloys (x = 2 and 3). Almost half of the yield strength comes from nano-sized L1 2 -type precipitates strengthening. The yield strength experienced sharp increment and the ductility showed an obvious decrease when the precipitated L1 2 phase increased in the range of 0–14.2 wt%, with corresponding Al and Ti concentrations in the range of x = 0-3. Furthermore, when the precipitated L1 2 phase exceeds 14.2 wt%, merely a slight increment in yield strength was observed, but the fracture strain declined to around 13%. The present results contribute to understanding the strengthening mechanisms of L1 2 -strengthened HEAs and may provide some reference for its application. • Effects of L1 2 contents on tensile properties were studied for (NiCo) 52+2x (AlTi) 4+2x Fe 29-4x Cr 15 HEAs. • The L1 2 -strengthened HEAs show a desired combination of tensile strength (1010-1074 MPa) and fracture strain (23-31%). • Precipitation strengthening from 15-26 nm nanoparticles contributes to half of the yield strength, around 318-375 MPa. [ABSTRACT FROM AUTHOR]