Effect of Zr + ion irradiation on the mechanical anisotropy of Zr–2.5%Nb pressure tube material

• Published in: Journal of nuclear materials 2010-10, Vol.405 (2), p.138-143
• Main Authors: Bose, B., Klassen, R.J.
• Format: Article
• Language: English
• Subjects: Applied sciences; Controled nuclear fusion plants; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Fission nuclear power plants; Fuels; Installations for energy generation and conversion: thermal and electrical energy; Nuclear fuels
• ISSN: 0022-3115; 1873-4820
• DOI: 10.1016/j.jnucmat.2010.08.001

Constant load pyramidal indentation creep tests were performed to study the effect of Zr + ion irradiation on the anisotropy of the local plastic deformation of Zr–2.5%Nb pressure tube material at 25 °C. The ratio of the average indentation stress σ ind t = 0 on the transverse normal (TN) plane relative to that on the axial-normal (AN) and radial-normal (RN) planes is 1.3 and 1.2 respectively. After Zr + ion irradiation the ratio of σ ind t = 0 on the TN plane relative to σ ind t = 0 on the AN and RN planes is 1.04 and 1.08 respectively indicating that the anisotropy of the yield stress is decreased as a result of irradiation hardening. The relative change in indentation stress Δ σ ˆ , as a result of irradiation damage, decreases with increasing resolved basal pole fraction in the indentation direction. This suggests that the Zr + ion irradiation damage has a greater effect on blocking the movement of dislocations on prismatic slip systems compared to pyramidal slip systems in the Zr–2.5%Nb pressure tubing. The activation energy Δ G 0 of the obstacles that limit the rate of dislocation glide during indentation creep at 25 °C does not change with indentation direction but does increase with increasing levels of Zr + ion irradiation damage.