Effect of oxygen and fabrication variables on the mechanical properties of Zircaloy tubing

The effects of oxygen concentration and fabrication variables on the mechanical properties of Zircaloy-2 tubing were investigated.The strength can be adjusted with a sma11loss of ductility by controlling oxygen concentration. Cold reduction in the range of this study has a large effect on recrystallization and ductility but little on texture. The Q value, the ratio of the wall thickness reduction to the diameter reduction during fabrication, has a significant effect on texture, hydride orientation and deformation behaviour.Tubes produced with a high Q value possess a superior combination of strength and ductility than tubes produced with a low Q value.In burst testing, axial contraction contributes greatly to the circumferential elongation due to the difficulty of thickness reduction in high- Q tubes. In low- Q tubes, both thickness reduction and axial contraction, which is smaller than that in high-Q tubes, contribute to the circumferential elongation.In practice, the optimum fabrication conditions for each fuel design must be determined.