Unveiling the effect of N interstitial on the mechanical properties of a CrFeCoNi medium entropy alloy

Abstract

The high-entropy alloy (HEA) field arise in the beginning of XXI century as novel class of promising materials with outstanding properties. However, since their discovery few studied concern their efforts on the investigation of interstitial elements effect in the microstructure as well as mechanical properties of such alloys. It is well-known that interstitial elements play a key role in the development of many kinds of steels. In this investigation, the effect of 1.5 at% of nitrogen alloying in a CrFeCoNi based medium-entropy alloy (MEA) was assessed in terms of microstructure and mechanical properties. It was observed that the N addition induced an increase in hardness, yield strength, and tensile strength without impair to the ductility of the alloy. A single fcc phase of observed for both CrFeCoNi and CrFeCoNiN alloys. Finally, the ductile characteristic of the fractured surface was verified by SEM analysis and confirmed by the presence of several dimples.