Effect of stacking fault energy on damage microstructure in ion-irradiated CoCrFeNiMn concentrated solid solution alloys

In order to understand the effect of stacking fault energy on microstructural evolution in concentrated solid solution alloys, Kr2+ ion irradiation was performed for FCC-type CoCrFeNiMnx alloys. During Kr2+ ion irradiation at 500 °C the formation of black dots, self-interstitial atom faulted loops and perfect loops were observed, but no observable voids were found in all the alloys. The comparison of microstructural evolution among CoCrFeNiMnx (x = 0.7, 1, 1.3) alloys revealed less faulted loop number density and size in CoCrFeNiMn1.3. The stacking fault energy of each alloy was investigated using the deformed CoCrFeNiMnx alloys, and it was revealed that CoCrFeNiMn1.3 had the highest stacking fault energy, which is higher value than that of 316SS. From these results, it is suggested that FeCrNiMn-based concentrated solid solution alloys could be well-designed by controlling the stacking fault energy with optimized Mn concentration as one of high radiation resistance structure materials.