Nanoparticles-strengthened high-entropy alloys for cryogenic applications showing an exceptional strength-ductility synergy
Abstract We designed a novel nanoparticles-strengthened high-entropy alloy, Ni 30 Co 30 Fe 13 Cr 15 Al 6 Ti 6 , which exhibits excellent strength-ductility combinations at both ambient and cryogenic temperatures. Especially at 77 K, an exceptional strength-ductility synergy can be observed, showing an ultrahigh tensile strength of 1.7 GPa and a large ductility of 51%, accompanied by a distinctive three-stage strain-hardening response. The precipitation-hardening behaviors and deformation micro-mechanisms were carefully investigated by the atom probe tomography and transmission electron microscope. The dynamic formation of nano-spaced stacking faults contributed to improved strain-hardening capacities, resulting in simultaneous enhancements of plastic deformation stability and tensile ductility at such high-strength levels.