Calculation of Threshold Displacement Energies in Austenitic Stainless Steels

Molecular dynamics (MD) simulations were applied to study primary damage formation in a Fe–Cr–Ni ternary model alloy with the 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 keV along fifteen non-equivalent crystallographic directions is employed for evaluation of the average threshold displacement energies. It is established that the average threshold displacement energies of Fe, Cr, and Ni atoms in the considered material are identical and equal to eV. As a function of , the actual average threshold displacement energy comprises of two linear segments that depend on the governing mechanism of primary damage formation. PKAs with energy , where 0.8 keV generate isolated vacancies and interstitial atoms, whereas PKAs with energy 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 on PKA energy .