Investigation on precipitation in Zircaloy-2 fuel cladding tube

Morphology of the precipitates and kinetics of precipitation in beta quench ed Zircaloy-2 has been investigated using small-angle X-ray scattering, wid e-angle X-ray scattering and transmission electron microscopy. Wide-angle X -ray scattering and transmission electron microscopy investigations indicat e the existence of two types of intermetallic precipitates, namely, tetrago nal Zr-2(Fe,Ni) and hexagonal Zr(Fe,Cr)(2). Pored exponents estimated from small-angle X-ray scattering profiles have been found to be less than four. These observations have been explained in terms of the existence of precip itates with two different morphologies, spherical and non-spherical (plate- like), which was also confirmed by transmission electron microscopy. The pr ecipitate size distribution for the virgin specimen shifts towards the smal ler radius side after beta quenching and starts growing gradually towards t he higher radius side with increase in aging time due to nucleation and gro wth. Phase separation is accompanied by dynamical scaling behaviour for dif ferent aging time. (C) 2000 Elsevier Science S.A. All rights reserved.