Enhancing the yield strength of Ni-Co-Cr-Fe-Al as-cast hypoeutectic high-entropy alloys by introducing γ′ precipitation

It is still a challenge to further increase the yield strength of eutectic high-entropy alloys, a promising multiple principal alloy system. By modifying the Ni: Co ratio to introduce the gamma ' phase, we developed a series of Ni60-xCoxCr10Fe10Al18Mo2 (x = 30, 20, 10, 0) casting hypoeutectic high-entropy alloys with improved yield strength and ductility. The increase of Ni concentration via decreasing Co concentration promotes the amount of FCC phase with nano gamma ' particles in it. The as-cast Ni60Cr10Fe10Al18Mo2 HEA with FCC/gamma'+B2 phase composition exhibits a superior sigma 0.2-831 MPa due to the formation of the gamma ' phase. The results provide a feasible route for developing high-performance Ni-Co-Cr-Fe-Al casting HEAs with multiscale microstructure.

Automated summary

It is still a challenge to increase the yield strength of eutectic high-entropy alloys. By modifying the Ni: Co ratio to introduce the gamma ' phase, a series of casting hypoeutectic high-entropy alloys with improved yield strength and ductility were developed. The results provide a feasible route for developing high-performance Ni-Co-Cr-Fe-Al casting HEAs with multiscale microstructure.