High temperature deformation behavior of Zr-1Nb alloy

Samples of annealed Zr-1Nb alloy were deformed under uniaxial compression in the temperature range of 600-900 °C and the strain rate range of 10−3 to 1s−1. The strain rate sensitivity map (m) was generated from the flow stress data. A high m of about 0.33 was obtained in the temperature range of 700-900 °C at a strain rate of 1 × 10− 3 s−1. Microstructures of the deformed samples were investigated using optical metallography and electron backscattered diffraction. The appearance of smaller deformation-free grains along the boundaries of deformed grains signified the occurrence of dynamic recrystallization in the samples deformed in conditions corresponding to high m values. Kinetic analysis of the deformation data in the 700-800 °C range yielded the apparent activation energy as 272 kJ mol−1, the stress exponent as 3.4, and the activation volume about 100b3 for Zr-1Nb alloy. Stress relaxation tests carried out at different temperatures indicated transitions in the creep behavior of the alloy with stress.