Nitrogen alloying of the multicomponent CoCrFeNiMn alloy: processing, microstructure and properties (Review)

In recent 20 years, multicomponent alloys attract much attention of the materials scientists, physics, chemists, metallurgist because they open the perspective for obtaining many exceptional properties by both compositional and microstructural design. A huge portion of the modern multicomponent alloys started from the well-known Cantor alloy (CoCrFeMnNi), which possesses perfect low-temperature ductility and strength, high corrosion resistance. To use it as a structural material in the industry, there is a need to improve its strength at elevated temperatures maintaining good low-temperature properties. Interstitial alloying has been recognized as an effective approach to enhance mechanical properties for the Cantor alloys family: it was successfully applied for the CoCrFeMnNi-C systems, but nitrogen-alloying of the Cantor alloy is still underinvestigated. The current issues to solve in this research field can be divided into technical (methods of high-nitrogen alloys fabrication, development of the thermomechanical treatments to obtain the best combination of the structural and functional properties) and physical one (mechanisms of interstitial hardening of the multicomponent alloys, the evaluation of the effect of nitrogen on deformation and fracture mechanisms of the alloys, etc.). This review is focused on the recent progress on the relationship between nitrogen-assisted hardening mechanisms and mechanical properties of the CoCrFeMnNi family alloys. The basic physical problems, including fabrication of the nitrogen-alloys Cantor alloy, solubility of N in CoCrFeMnNi system, as well as the influence of nitrogen alloying on strength properties of the CoCrFeMnNi-N alloys have been discussed.