Dislocation cross-slip controlled creep in Zircaloy-4 at high stresses

The constriction energy of screw dislocations of 150 kJ/mol is in agreement with the values reported in the literature for zirconium and other HCP metals. Further analysis of the yield strength and the activation volume data obtained from stress relaxation tests in the temperature range 500-600 °C favors cross-slip of screw dislocations as the rate controlling mechanism over the test conditions.