Blister growth in zirconium alloys: experimentation and modeling

• Published in: Journal of nuclear materials Vol. 229; no. 1-3; pp. 36 - 47
• Main Authors: Domizzi, Gladys, Enrique, Raúl A., Ovejero-García, José, Buscaglia, Gustavo C.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 02.04.1996
• ISSN: 0022-3115; 1873-4820
• DOI: 10.1016/0022-3115(95)00204-9

Hydrogen redistribution in the presence of a cold spot is considered, with hydrogen concentrations above the solid-solubility limit and thus with hydrogen flowing through a hydride-matrix mixture. Fully-hydrided regions (frequently called blisters) grow in the samples, beginning at the cold spot. Under equivalent conditions, the experiment is carried out on several Zr-2.5% Nb samples, allowing for the hydrogen migration times to vary from 1 × 105 to 6 × 105 s, so as to construct a blister-growth curve. Metallographic examination of the samples is performed before and after the imposition of the thermal gradient. A mathematical model is then presented, and the corresponding equations are numerically solved by means of a finite element method, refining the discretization so as to render approximation errors unimportant. Agreement between model and experiment is shown to be quite good for migration times greater than 3 × 105 s. For shorter times, implying small blisters around the cold spot, discrepancies arise between model and experiment, which are attributed to errors in estimating the local temperature field near the sample surface.