Influence of water vapour on the zircaloy-4 oxidation at high temperature - Stress determination by in situ X-Ray diffraction

Abstract

A key parameter for the understanding the effect of water vapour on the oxidation mechanism is the determination of the stress level in the monoclinic zirconia scale and in the Zircaloy-4 (Zy-4) substrate at high temperature. In order to provide an accurate description of the microstructure of the oxide layers, X-ray diffraction (XRD) analyses have been performed in situ under dry and wet oxidizing environments at high temperature on Zy-4 flat sheet samples. The aim of the present work is to show the influence of water vapour on the stress developed at high temperature in the oxide scale as well as inside the alloy. The stress evolution during cooling to room temperature has also been determined.