TY - JOUR

T1 - Stabilization of mechanical strength in a nanocrystalline CoCrNi concentrated alloy by nitrogen alloying

AU - Moravcik, Igor

AU - Alfreider, Markus

AU - Wurster, Stefan

AU - Schretter, Lukas

AU - Zadera, Antonin

AU - Pernica, Vítezslav

AU - Čamek, Libor

AU - Eckert, Jürgen

AU - Hohenwarter, Anton

N1 - Publisher Copyright: © 2025 The Authors

PY - 2024/12/27

Y1 - 2024/12/27

N2 - The mechanical performance and microstructures of a CoCrNi medium-entropy alloy (MEA) and NCoCrNi, alloyed with 0.5 at% N, after high pressure torsion (HPT) and subsequent annealing treatments in a temperature range of 150–1000 °C were investigated. The introduction of N results in a reduction of grain size by 40 % and ∼10–15 % increased hardness and bending strength after HPT. Both materials showed strain hardening and plasticity after HPT even at these strength levels over 1500 MPa which is induced by the saturated nanocrystalline state. Annealing at intermediate temperatures of 300–500 °C resulted in an additional increase of hardness and strength by ∼20–40 %, compared to the HPT deformed state. This effect was ∼10 % more pronounced in the nitrogen alloyed CoCrNi that also showed better thermal stability. However, the increase in strength after 500 °C annealing was accompanied by a drastic loss of ductility in both materials.

AB - The mechanical performance and microstructures of a CoCrNi medium-entropy alloy (MEA) and NCoCrNi, alloyed with 0.5 at% N, after high pressure torsion (HPT) and subsequent annealing treatments in a temperature range of 150–1000 °C were investigated. The introduction of N results in a reduction of grain size by 40 % and ∼10–15 % increased hardness and bending strength after HPT. Both materials showed strain hardening and plasticity after HPT even at these strength levels over 1500 MPa which is induced by the saturated nanocrystalline state. Annealing at intermediate temperatures of 300–500 °C resulted in an additional increase of hardness and strength by ∼20–40 %, compared to the HPT deformed state. This effect was ∼10 % more pronounced in the nitrogen alloyed CoCrNi that also showed better thermal stability. However, the increase in strength after 500 °C annealing was accompanied by a drastic loss of ductility in both materials.

KW - CoCrNi-alloy

KW - High pressure torsion

KW - Interstitials

KW - Medium entropy alloy

KW - microcantilevers

KW - severe plastic deformation

UR - http://www.scopus.com/inward/record.url?scp=85213883119&partnerID=8YFLogxK

U2 - 10.1016/j.msea.2024.147757

DO - 10.1016/j.msea.2024.147757

M3 - Article

AN - SCOPUS:85213883119

VL - 924.2025

JO - Materials Science and Engineering: A

JF - Materials Science and Engineering: A

SN - 0921-5093

IS - February

M1 - 147757

ER -