Deformation mechanism study of a hot rolled Zr-2.5Nb alloy by transmission electron microscopy. II. In situ transmission electron microscopy study of deformation mechanism change of a Zr-2.5Nb alloy upon heavy ion irradiation

• Published in: Journal of applied physics 2015-03, Vol.117 (10)
• Main Authors: Long, Fei, Daymond, Mark R., Yao, Zhongwen, Kirk, Marquis A.
• Format: Article
• Language: English
• Subjects: Applied physics; Basal plane; Deformation; Deformation effects; Deformation mechanisms; Dislocation loops; Dislocation pinning; Gliding; Heavy ions; Ion irradiation; MATERIALS SCIENCE; Microstructure; Plastic instability; Stability; Transmission electron microscopy; Twinning; Zirconium base alloys
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.4913614

The effect of heavy-ion irradiation on deformation mechanisms of a Zr-2.5Nb alloy was investigated by using the in situ transmission electron microscopy deformation technique. The gliding behavior of prismatic 〈a〉 dislocations has been dynamically observed before and after irradiation at room temperature and 300 °C. Irradiation induced loops were shown to strongly pin the gliding dislocations. Unpinning occurred while loops were incorporated into or eliminated by 〈a〉 dislocations. In the irradiated sample, loop depleted areas with a boundary parallel to the basal plane trace were found by post-mortem observation after room temperature deformation, supporting the possibility of basal channel formation in bulk neutron irradiated samples. Strong activity of pyramidal slip was also observed at both temperatures, which might be another important mechanism to induce plastic instability in irradiated zirconium alloys. Finally, {011¯1}⟨01¯12⟩ twinning was identified in the irradiated sample deformed at 300 °C.