MD Simulations of Collision Cascades in α-Ti. Statistics and Governing Mechanisms of Point Defect Cluster Formation

The outcomes of molecular dynamics simulations of primary damage formation in collision cascades initiated by primary knock-on atoms (PKA) with PKA energy 5 keV ≤Epka≤ 25 keV in α-titanium at 100 K ≤T≤ 900 K temperatures have been analysed. The fraction of vacancies, εv, and self-interstitial atoms (SIA), εi, in point defect clusters created in isolated collision cascades was evaluated. The corresponding averages ⟨εv⟩ and ⟨εi⟩ over cascade series with the same (Epka, T) parameters, the average size ⟨Nvac⟩ and ⟨Nsia⟩ of vacancy and SIA clusters, respectively, and the average vacancy ⟨Yvac ⟩ and SIA ⟨Ysia ⟩ cluster-per-cascade yield were found as well. Possible governing mechanisms have been suggested to explain ⟨εv⟩, ⟨εi⟩ , ⟨Nvac⟩, ⟨Nsia⟩, ⟨Yvac⟩ and ⟨Ysia⟩ dependence on (Epka,T).