A novel nanostructure to achieve ultrahigh strength and good tensile ductility of a CoCrFeNiMn high entropy alloy.

A CoCrFeNiMn high entropy alloy with a novel nanostructure consisting of ultrafine grains, TiO(C) nanoparticles and nanotwins has been fabricated. It achieves an ultrahigh tensile yield strength of 1507 MPa by coupling multiple strengthening mechanisms, including grain boundary strengthening, twin boundary strengthening, nanoparticle strengthening and dislocation strengthening. The work hardening ability is also improved by coupling the interactions of dislocations with nanoparticles and nanotwins during plastic deformation, leading to a good tensile ductility with a uniform elongation of 4.7%.