Publications

Yield strength increase of a CoCrNi medium entropy alloy by interstitial nitrogen doping at maintained ductility

Moravcik, I. and Hadraba, H. and Li, L. and Dlouhy, I. and Raabe, D. and Li, Z.

SCRIPTA MATERIALIA
Volume: 178 Pages: 391-397
DOI: 10.1016/j.scriptamat.2019.12.007
Published: 2020

Abstract
We show that interstitial nitrogen doping improves the tensile properties of a CoCrNi alloy. A material with 0.5 at% interstitial nitrogen was compared to a nitrogen-free CoCrNi alloy. The nitrogen-doped variant has a stable, single-phase face-centered cubic (FCC) lattice structure without nitrides, also after different annealing treatments (800–900 °C, 10 and 30 min). The nitrogen caused an increase in yield strength by 24–33% at identical ductility compared to the nitrogen-free material with similar grain size. The strengthening effect of nitrogen was explained in terms of the simultaneous increase of the lattice friction stress and of the Hall-Petch coefficient. © 2019

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