A study of primary damage formation in collision cascades in titanium

Abstract

Molecular dynamics (MD) simulations were applied to study radiation damage formation in collision cascades initiated by primary knock-on atoms (PKA) with energy EРКА = 5, 10, 15 and 20 keV in α-Ti at T = 100, 300, 600 and 900 K ambient temperatures. A series of 24 collision cascades was simulated for each (EРКА, Т) pair. The necessary sampling set size was justified by a simple a posteriori procedure. The number of Frenkel pairs and the fraction of vacancies, εv, and self-interstitial atoms (SIAs), εi in point defect clusters were evaluated as functions of (EРКА, Т). It was established that collision cascades in α-Ti are extended along PKA trajectories and tend to split into subcascades. In contrast to other elemental metals with close-packed crystal structure, εv≥ εi in collision cascades in α-Ti. Moreover, both εv and εi ௜demonstrate weak temperature dependence. This is anindirect indication that both vacancy and SIA clusters created in collision cascades in α-Ti are stable in the considered temperature range