Enhanced tensile properties and wear resistance of additively manufactured CoCrFeMnNi high-entropy alloy at cryogenic temperature

Here, bulk CoCrFeMnNi high-entropy alloy was prepared via laser melting deposition, and its microstructure and mechanical properties at room and cryogenic temperature were investigated by a series of microstructural characterizations and mechanical tests. The results showed that the as-built samples possessed a single fcc phase and highly dense microstructures. Compared to the mechanical properties at room temperature, tensile properties, microhardness and wear resistance of the as-built samples showed a significant enhancement at cryogenic temperature, which was attributed to the deformation mechanism converting from dislocation slipping to deformation twinning at cryogenic temperature. The formation of deformation nanotwins significantly improved the deformation resistance in cryogenic conditions, and the sliding wear in the liquid nitrogen could decrease the oxygen concentration, suppress the generation of oxide particles and thus enhance the wear resistance. Graphical abstract