The effect of neutron irradiation on mechanical properties of rhenium

Abstract

Polycrystalline and single crystal rhenium tensile specimens have been neutron irradiated at 50°C to fluences up to 2.6 × 10¹⁹ n/cm² and subsequently tested in tension. The microstructure of the single crystals was examined by transmission electron microscopy. The yield strengths of the polycrystalline specimens increased from 19,000 psi in the unirradiated material to 143,000 psi after a fluence of 2.6 × 10¹⁹ n/cm². Slip was observed on the basal and prismatic planes and (1121) twinning was found to be the main twinning mode in the single crystals. The single crystal yield strengths also increased markedly with fluence and were found to increase at a greater rate in those crystals oriented for prismatic slip. The radiation damage greatly retarded twin growth at the higher fluences but did not appear to affect twin nucleation. Channeling of dislocation through the small defect clusters occurred in the irradiated specimens. Deformation twinning did not result in channeling type behavior although anomalous channels parallel to, but outside, the twins were observed.