Observation of second-phase particles in bulk zirconium alloys using synchrotron radiation

To further advance the mechanistic understanding of microstructural evoluti on in zirconium alloys for high burnup applications, it is important to obt ain a quantitative measurement of the volume fractions of second-phase prec ipitates present in the bulk alloys as a function of the heat treatment and irradiation fluence. In this work, X-ray diffraction from a synchrotron ra diation source was used to identify and follow the growth kinetics of secon d-phase particles in zirconium alloys. The high energy flux, energy resolut ion and signal-to-noise ratio of this light source allowed us to study the very small (<0.2-0.4%) precipitate volume fractions in these alloys. A prel iminary calculation of the precipitate volume fraction as a function of cum ulative annealing parameter (CAP) showed the precipitate volume fraction in creases rapidly above 10(-19) h and saturates at about 10(-17) h. (C) 2001 Elsevier Science B.V. All rights reserved.