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

摘要

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 character-izations and mechanical tests.The results showed that the as-built samples possessed a single fcc phase and highly dense microstructures.Compared to the mechanical prop-erties at room temperature,tensile properties,microhard-ness and wear resistance of the as-built samples showed a signiflcant 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 signiflcantly improved the deformation resis-tance 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.