Irradiation growth of zirconium single crystals

• Published in: Journal of nuclear materials Vol. 101; no. 1; pp. 28 - 37
• Main Authors: Carpenter, G.J.C., Murgatroyd, R.A., Rogerson, A., Watters, J.F.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.10.1981
• ISSN: 0022-3115; 1873-4820
• DOI: 10.1016/0022-3115(81)90441-4

Irradiation growth of zirconium single crystals has been studied during neutron irradiation at 353 K and 553 K at fluences up to 2× 10 25 n/m 2. The results may be summarized as follows: (a) there was an expansion parallel to the a-axis and a c-axis contraction; (b) the growth strains were small (~10 −4), (c) growth saturated at fluences less than ~5× 10 24 n/m 2, (d) the growth behaviour was only weakly dependent on temperature for the range studied, (e) there was a calculated volume increase of the same order as the growth strain, and (f) single crystals prepared from stock of iodide and zone-refined purity showed similar growth behaviour at 553 K. The a-axis expansion is attributed to the annihilation of an excess of interstitials at < a>-type dislocations and interstitial loops. The c-axis contraction may be caused by: (1) elastic relaxation around vacancies or small vacancy clusters, (2) non-linear elastic effects at the dislocation cores of small 〈 a〉-type loops, or (3) sub-microscopic vacancy loops with 〈 c〉-component Burgers vectors. Comparison with data from polycrystalline zirconium confirms that grain boundaries can play an important role in the irradiation growth of zirconium.