Study of the effect of PKA energy on long-term microstructural evolution in irradiated FeMnNi alloys

Herein, we used a multiscale simulation method to investigate the variation rule of the long-term feature of irradiation defects versus primary knock-on atom (PKA) energies (5 keV–100 keV) in dilute FeMnNi alloys. Simulation results presented a significant effect of PKA energy on irradiation microstructure, the density of large defect clusters increases significantly with increasing PKA energy, and the difference in the number density of visible defect clusters can reach several times to about one order of magnitude at the dose rate of 1 × 10 −4 dpa/s. The migration events of point defects (PD) decrease significantly with increasing PKA energy, suggesting that a higher PD flux at lower PKA energy could probably enhance the radiation-induced segregation (RIS) in alloys. Additionally, since the generation mechanism involves specific SIA-cluster sizes, the production ratio of <100>-type SIA loops could also influenced by PKA energies. Our simulation results align with experimental differences in the microstructure of light and heavy-ion irradiated alloys. This work clarified the mechanism of PKA energy effects in dilute alloys and provides a certain scientific basis for the comparison and emulation of different particle irradiation.