Heavy ion irradiation effects on CrFeMnNi and AlCrFeMnNi high entropy alloys

Co-free but Al-included medium/high entropy alloys (M/HEAs) have gained increasing interests due to their lower cost and the potential to tune the multi-phase microstructure. The irradiation response of two Co-free HEAs, face-centered cubic (FCC) CrFeMnNi with limited Cr enriched alpha' phase and body-centered cubic (BCC) AlCrFeMnNi with B2 s phase and nanoprecipitates were explored. Ion irradiations using 5 MeV Fe 2 + ions were performed at 500 degrees C to a peak fluence of 50 and/or 100 displacements per atom (dpa). In dual-phase AlCrFeMnNi, there was no significant radiation induced segregation or chemical intermixing at the coherent matrix (FeCrMn-rich)/second phase (AlNi-rich) boundaries. In CrFeMnNi, limited voids were only detected at the peak damage location of similar to 50 dpa. On the other hand, voids were widely distributed in AlCrFeMnNi: under 50 and 100 dpa irradiation conditions, voids were found with larger dimension and denser distribution in the FeCrMn-rich matrix, smaller and slightly lower density in an AlNi-rich second phase. In addition, the diameter of the FeCMn-rich nanoprecipitates didn't reveal any tendency of dissolution or growth. This is correlated with their superior structural stability against irradiation. Significant radiation-induced hardening (increases from 3.8 +/- 0.2 GPa to 4.7 +/- 0.6 GPa) was measured in CrFeMnNi, but only - 4% hardness increase (from 7.4 +/- 0.8 GPa to 7.7 +/- 0.4 GPa) was noted in AlCrFeMnNi. In addition to the radiation-induced defects, such as voids, dislocation loops and point defects, other factors, such as chemical short-range ordering may play an important role. (c) 2022 Published by Elsevier B.V.

Automated summary

Co-free but Al-included medium/high entropy alloys (M/HEAs) have attracted attention for their lower cost and the ability to tune multi-phase microstructures. In this study, the irradiation response of two Co-free HEAs, FCC CrFeMnNi and BCC AlCrFeMnNi, was explored. It was found that radiation-induced segregation and intermixing were minimal in the AlCrFeMnNi alloy, while limited voids were detected in the CrFeMnNi alloy. Additionally, the FeCrMn-rich nanoprecipitates in AlCrFeMnNi showed superior structural stability against irradiation.