Characterization of Hot Deformation Behavior of Zr-4 Alloy in Material Application Area

The hot deformation behavior of Zr-4 alloy was studied in the temperature range 650-900 degrees C and strain rate range 0.005-50s(-1) using processing maps. The processing maps revealed three domains: the first occurs in the temperature range 780-820 degrees C and strain rate range 0.005-0.05s(-1), and has a peak efficiency of similar to 45% at 790 degrees C and 0.005s(-1); the mechanism is the dynamic recrystallization. The second occurs in the temperature range greater than 900 degrees C and strain rate range 0.05-0.8s(-1), and has a peak efficiency of similar to 40% at 900 degrees C and 0.5s(-1), which are the domains of dynamic recovery. In addition, the instability zones of flow behavior can also be recognized by the maps in the temperature range 650-780 degrees C and strain rate range 0.01-0.1s(-1), which should be strictly avoided in the processing of the material. Zr-4 alloy is the material for pressure tube applications in nuclear reactors and has better strength and a lower rate of hydrogen uptake compared to other materials under similar service conditions.