Effects of Mn Content on Microstructure and Mechanical Properties of Co-Free Medium Entropy Alloys in the Cr-Fe-Mn-Ni System

This study investigates the microstructure and mechanical properties of four different Cr-Fe-Mn-Ni medium entropy alloys (MEAs) for potential nuclear applications. In this work, Cr-Fe-Mn-Ni medium entropy alloys were fabricated and analyzed. Nano hardness measurements showed higher hardness in Cr0.8FeMn1.3Ni, attributed to the increased atomic size difference caused by higher Mn content. The strength of Cr-Fe-Mn-Ni MEAs is mainly affected by solid solution strengthening and grain boundary strengthening. The tensile test revealed that Cr0.8FeMn1.3Ni exhibited the highest strength, which is correlated with its large hardness and small grain size. The increase of Mn content leads to greater atomic size difference, enhancing the hardness and reducing the grain size. Cr0.8FeMn1.3Ni shows superior strength and higher hardness compared to other Cr-Fe-Mn-Ni MEAs, suggesting its potential for nuclear applications.