SRIM-Based and Advanced Defect Modeling Assessment of 3 MeV Proton Irradiation Damage in Nickel-Base Alloys

Nickel base alloys are widely used in high temperature, radiation, and corrosive environments due to their mechanical strength and chemical stability. Under irradiation, energetic particles generate primary knock-on atoms (PKAs), displacement cascades, and surviving point defects (e.g., stable vacancies) that can degrade performance. Here, proton-induced primary damage in three Ni-base alloys (KHN77TYUR, Inconel 718, and Inconel X750) is evaluated computationally using SRIM/TRIM in Full Damage Cascades mode supplemented by athermal recombination-corrected dpa (〖"dpa" 〗_"arc" ) modeling, partial elemental displacement analysis, co-implanted hydrogen depth profiling, stopping power ratio evaluations, and crystalline channeling assessment. A 3 MeV proton beam incident on a 100 μm-thick target is simulated. Depth-resolved results show that proton interactions and damage production are strongly non-uniform, with displacement damage concentrated near the end-of-range region (approximately 40 μm under the specified simulation conditions). Electronic stopping dominates over most of the proton trajectory, whereas the relative contribution of nuclear stopping increases markedly as the protons approach the end of their range. The three alloys exhibit similar projected ranges of approximately 39.5–40.2 μm, while their calculated displacement rates differ because of composition-dependent collision processes, threshold displacement energies, and atomic densities.Applying an arc-dpa correction with a defect-survival efficiency of approximately 0.24 reduces the NRT displacement rates by about 76%, yielding arc-dpa rates of 7.22 × 10⁻⁷ dpa/s for Inconel 718, 7.66 × 10⁻⁷ dpa/s for KHN77TYUR, and 7.93 × 10⁻⁷ dpa/s for Inconel X750.Under the stated beam conditions and modeling assumptions, the predicted primary-damage rate follows the order Inconel X750>KHN77TYUR >Inconel 718.