Study on Recrystallization of Cold-worked and β-quenched zirconium alloys

The observation of microstructure and the hardness test of Zr-Sn binary and Zircaloy-4 alloys were performed to investigate the recrystallization of cold-worked and β-quenched Zr alloys. All specimens were heat-treated in vacuum condition at various temperatures. From the observation of microstructures of cold-worked and β-quenched Zr alloys, the cold-worked specimens were shown to keep the cold-worked micro- structure as annealing temperature increased up to 500 deg C and the recrystallization was completed at between 550 deg C and 700 deg C. Meanwhile, the recrystallization of β-quenched Zr alloys was started at about 700 deg C. In all specimens of cold-worked and β-quenched Zr alloys, the hardness value tended to be consistent with microstructure. Although the cold-worked and the β-quenched specimens had an equal initial hardness value, the recrystallization behavior was indicated to be different from each other, which means that recrystallization mechanism is different from each other