Characterization of argon ion irradiation induced changes in microstructure and mechanical property of binary Zr−2.9 wt% Sn alloy

Abstract

In this study, we report the investigation of microstructural and mechanical property changes in binary Zr−2.9 wt% Sn alloy induced by room temperature heavy ion (Ar9+) irradiation to fluences ranging from 3.1 × 1015 to 4.17 × 1016 Ar9+cm-2. S-parameter, probed using positron annihilation spectroscopy, showed an increase with fluence. Changes in microstructural attributes, viz., the coherently scattering domain size, microstrain, dislocation density and, residual stress, were ascertained through grazing incidence X-ray diffraction. A decrease in domain size and increase in both microstrain and dislocation density were observed in addition to the development of compressive stress in place of tensile after irradiation. The hardness of the irradiated samples, probed by nanoindentation, was found to be higher in comparison to unirradiated one. Transmission electron microscopy investigation exemplified the formation of <a>- and <c>- type dislocation loops upon irradiation. The above findings could be rationalized on the basis of the defects generated during Ar9+ heavy ion irradiation.