Synergistic regulation of temperature and primary knock-on atom energy on irradiation damage evolution in tantalum: A molecular dynamics study

Tantalum is a candidate material for advanced nuclear systems, but its irradiation damage mechanisms remain unclear. Using molecular dynamics with the UNEP-v1-ZBL machine-learning potential, we simulated BCC Ta under 1-50 keV PKA irradiation at 300-900 K. Results show that threshold displacement energy decreases with temperature and exhibits anisotropy. Defect evolution displays strong energy-temperature coupling: low-energy cascades (≤5 keV) follow monotonic displacement chain behavior, while high-energy cascades (≥15 keV) are governed by competition between thermal spike formation and energy dissipation. Interstitial clusters outnumber vacancy clusters due to low migration energy and ⟨111⟩ diffusion. Cascade morphology controls final damage accumulation by modulating defect spatial distribution. These atomic-scale insights provide theoretical foundations for accurate damage modeling and radiation-resistant material design.