Low-Temperature Electron and Alpha-Particle Irradiation of Titanium

The recovery of point defects produced by 1.2-MeV electron and 40-MeV $\alpha$-particle irradiation has been studied from 50 to 270°K. The recovery spectrum qualitatively resembles that of copper, although shifted to higher temperature. The influence of varying irradiation dose, preirradiation at elevated temperatures, predeformation and dilute alloying were also studied. The recovery below 150°K is dominated by the annihilation of Frenkel pairs, with long-range or uncorrelated migration of the interstitial beginning at approximately 120°K. The recovery of annealed samples irradiated to relatively low dose is characterized by super-recovery. A model involving the migration of interstitial hydrogen impurities from interstitial to substitional sites is proposed to explain this phenomenon.