Strengthening of a CrMnFeCoNi high-entropy alloy by carbide precipitation

Gao, N. and Lu, D.H. and Zhao, Y.Y. and Liu, X.W. and Liu, G.H. and Wu, Y. and Liu, G. and Fan, Z.T. and Lu, Z.P. and George, E.P.

Volume: Pages: 1028-1035
DOI: 10.1016/j.jallcom.2019.04.121
Published: 2019

The equiatomic CrMnFeCoNi high-entropy alloy (HEA) exhibits outstanding toughness and excellent strength-ductility combination at cryogenic temperatures. However, its strength is relatively low at room temperature. In order to strengthen this HEA, microalloying additions of 0.8 at.% Nb and C were made and its properties and microstructure evaluated. It was found that the microalloying resulted in the formation of carbide precipitates and a reduction of the grain size to ∼2.6 μm. As a result, the room-temperature tensile yield strength (732 MPa) of the microalloyed HEA is roughly double that of the base HEA (with a concomitant increase in the ultimate strength) while its ductility is maintained at a relatively high level (elongation to fracture of ∼32%). The strengthening is due to precipitation hardening from the nanoscale carbide particles and grain refinement. © 2019

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