The positron-dislocation interaction studied in deformed zinc single crystals

Abstract

The pyramidal dislocations and parallel basal dislocations induced from the deformation with compressive loading normal to the (0001) plane and to the (1012) plane of the Zn single-crystal specimen are observed by TEM. The positron lifetime experiments for the samples measured at 100 K yield two different trapping lifetimes. It is found that the lifetime tau d of positrons trapped and annihilated in basal dislocations lines increases by about 20% compared with that in bulk ( tau d=177+or-2 ps) and it is shown that a positron would be trapped in deeper traps (jogs) via the dislocation when the jog concentration along it is sufficiently high, with the annihilation lifetime close to that in a monovacancy. The intensities of the two trapping components decrease evidently with increase in temperature increasing to room temperature. The difference between positron-vacancy and positron-dislocation interactions are discussed.

Plastic Deformation of Nanocrystalline Zinc Investigated by Positron Annihilation Lifetime Spectroscopy

“…The lifetime 𝜏 1 is about 178 ps for the uncompressed bulk sample. The calculated bulk lifetime of Zn is about 158 ps, [16] and the experimental data reported in the literature are 152 ps, [16] 160 ps [9] and 165 ps. [11] Apparently, the lifetime 𝜏 1 of 178 ps is larger than all of them, but smaller than the positron lifetime 057804-2 in a monovacancy (220 ps in Ref.…”