ABSTRACT
The Zr-based alloys are extensively applied in the field of nuclear technology. Alloyed with Sn and Fe, Zr is the main element in the zircaloy-type alloys, currently vastly used as structural elements and as containers of burnable elements in nuclear reactors. This ternary metallurgical system is also a component of more recently developed alloys such as Zirlo (USA). Although Zr is a major component in all of them, it is most important to know the phase diagrams of their components as best as possible. The Fe-Sn-Zr phase diagram has been systematically studied by our research team for many years. Considerable advancement has been made in the design of the phase diagram at 800°C, however, some regions in the Gibbs triangle are still unsolved. In order to evaluate these regions experimentally, a ternary alloy set was designed and prepared. These alloys were thermally treated at the chosen temperature for 2928 hours, and characterized by applying metallography techniques, X-ray diffraction and microanalysis. The presence of Y and Fe6Sn6Zr was confirmed, the presence of phase X” was verified, and 2- and 3-phase existence fields were determined. Finally, phase balance boundaries in the regions under study were traced, completing, to a great extent, the phase diagram for the isothermal cut analysed.
Keywords
Nuclear materials; Phase diagram; Zirconium
