Аннотация
Molecular dynamics (MD) simulations were applied to study primary damage formation in a Fe–Ni–Cr ternary model alloy with chemical composition that coincides with Fe, Ni, and Cr content in AISI type 304 stainless steel. A representative sample of 12 960 radiation damage formation events initiated by Fe, Ni, and Cr primary knock-on atoms (PKA) with PKA energy 100 eV ≤EPKA≤ 5 keV along fifteen crystallographic directions is employed for evaluation of the average threshold displacement energies. It is established that the average threshold displacement energies of Fe, Ni, and Cr atoms in the considered material are identical and equal to ⟨Ed⟩=28±1 eV. As a function of EPKA, the actual average threshold displacement energy Ed comprises of two linear segments that depend on the governing mechanism of primary damage formation. PKAs with energies EPKA≤Ecc, where Ecc≈0.8 keV, generate isolated vacancies and interstitial atoms, whereas PKAs with energies EPKA≥Ecc produce radiation damage in collision cascades. Using the obtained results of MD simulations, we modified the cascade function in the Kinchin-Pease model in order to take into account the dependence of the actual threshold displacement energy Ed on PKA energy EPKA.