Characterization of hot-deformation behaviour of Zircaloy-2: a comparison between kinetic analysis and processing maps

The hot deformation mechanisms in Zircaloy-2 with beta transformed initial microstructure are evaluated in the temperature range 650 to 950 degrees C and strain rate range 10(-3) to 100 s(-1) according to the principles of thermally activated deformation (kinetic analysis). Depending on the strain rate and temperature, various deformation mechanisms, namely dynamic recystallization, dynamic recovery, and superplasticity, have been identified on the basis of activation energy, stress exponent (or strain-rate sensitivity), metallography on deformed specimens, and from the nature of the stress strain curve. An attempt has also been made to correlate the compression test data with those of extrusion data using kinetic analysis. Finally the results of the kinetic analysis have been compared with the predictions of processing maps generated earlier.