Phase Transformation Temperatures and Solute Redistribution in a Quaternary Zirconium Alloy

This study investigates the phase stability and redistribution of solute during heating and cooling of a quaternary zirconium alloy, Excel (Zr-3.2Sn-0.8Mo-0.8Nb). Time-of-flight neutron diffraction data are analyzed using a novel Vegard’s law-based approach to determine the phase fractions and location of substitutional solute atoms in situ during heating from room temperature up to 1050 °C. It is seen that this alloy exhibits direct nucleation of the β_Zr phase from martensite during tempering, and stable retention of the β_Zr phase to high temperatures, unlike other two-phase zirconium alloys. The transformation strains resulting from the \(\alpha \leftrightarrow \beta \) transformation are shown to have a direct impact on the development of microstructure and crystallographic texture.