Molecular dynamics simulations of high-energy radiation damage in hcp-titanium considering electronic effects

Abstract

Titanium and its alloys are widely used as structural materials under extreme conditions due to their exceptional specific strength. However, comprehensive studies on their high-energy radiation damage remain limited. Considering electronic effects, molecular dynamics simulations were performed to explore high-energy radiation damage in hcp-titanium (hcp-Ti), focusing on displacement cascades induced by primary knock-on atoms (PKAs) with energies ranging from 1 to 40 keV. This study investigates the generation and evolution of point defects resulting from collisional cascades, particularly examining the influence of PKA energy. Additionally, the distribution and morphology of clustering defects from these events were quantitatively investigated and qualitatively visualized. The results show a significant dependence of surviving defects on PKA energies, highlighting a critical range that exhibits a shift in cascade morphology. Furthermore, it is demonstrated that PKA energy significantly influences the formation and growth of defect clusters, with both interstitials and vacancies showing increased cluster fraction and sizes at higher PKA energies, albeit with different tendencies in their formation and aggregation behaviors. Morphological analysis emphasizes the role of subcascades and provides further insights into the mechanisms of defect evolution behind high-energy radiation damage. Our extensive study across a broad range of PKA energies provides essential insights into the understanding of high-energy radiation damage in hcp-Ti.