Transformation Heat Treatment of Rapidly Quenched $ \hbox{Nb}_{3}\hbox{Al}$ Precursor Monitored In Situ by High Energy Synchrotron Diffraction

Nb 3 Al superconductors are studied for use in high field magnets. Fine-grained Nb 3 Al with nearly stoichiometric Al content is obtained by a rapid heating quenching and transformation process. We describe a nondestructive in situ study of the transformation process step of a rapid heating quenching Nb 3 Al precursor wire with ramp rates of either 120 °C/h or 800 °C/h. High-energy synchrotron X-ray diffraction measurements show the transformation from a Nb(Al) SS supersaturated solid solution into Nb 3 Al. When heating with a ramp rate of 120 °C/h, a strong reduction of the Nb(Al) SS (110) diffraction peak component is observed when the temperature exceeds 660 °C. Additional diffraction peaks are detectable in the approximate temperature interval 610 °C -750 °C and significant Nb 3 Al growth is observed above 730 °C.