Oxidation processes in zircaloy

A study by transmission electron microscopy has been made of the incorporation and oxidation of intermetallic precipitates Zr(Cr,Fe)2 into the uniform oxide layer of Zircaloy-4. The main results are: - most of the precipitates are incorporated unoxidized into the oxide layer and are later oxidized. - iron concentration evolves significantly during oxidation, especially before the transition, segregating to the precipitate-matrix interface, occasionally as metallic iron, before being dissolved in the matrix. The behavior of the precipitates during oxidation is discussed in the light of previous work and possible consequences to the oxidation process are considered. (orig.)