Thermally activated deformation of alpha zirconium

The effect of temperature on the yield stress of polycrystalline α-zirconium has been examined at temperatures between 77 and 900 K. A strong temperature dependence on the yield stress (interrupted in the temperature ranges 300 to 400 K and 500 to 700 K where the yield stress is independent of temperature) indicates the occurrence of the thermally activated processes during deformation. The activation volume at the onset of deformation has been determined as a function of temperature in the range 77 to 523 K. (author)