Solid solution hardening with nitrogen atoms of (CrFeMn)₆₀Co₃₅Ni_4.8N_0.2 high-entropy alloy single crystals

For the first time, it was shown on the [͞144]- and [͞111]-oriented (CrFeMn)60Co35Ni4.8N0.2 high-entropy alloy single crystals that alloying with nitrogen at a concentration of 0.2 at.% suppresses the FCC-HCP martensitic transformation developing in (CrFeMn)60Co35Ni5 single crystals without nitrogen and stabilizes the FCC phase. The temperature dependence of critical shear stresses τcr( T ) is determined by slip and the τcr does not depend on the crystal orientation in the temperature range of 77-573 K under tension. It was shown that nitrogen at a concentration of 0.2 at.% leads to localization of deformation and the development of a planar structure with dislocation pile-ups in the temperature range of 77-296 K. The orientation dependence of the “stress-strain” curves, strain hardening coefficient θ = d σ/ d ε, and plasticity is determined by the number of active slip systems and twinning. In [͞111] orientation, θ = dσ/dε = 2330 MPa has a maximum value at 77 K at the development of slip in several systems, stacking faults, and twinning. In [͞144] orientation, at the development of slip predominantly in one system with θ = dσ/dε = 670 MPa, the maximum plasticity of 67% is realized at a temperature of 296 K.

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