Stress reorientation of hydrides in recrystallized Zircaloy-2 sheet

A series of measurements has been performed on unirradiated recrystallized Zircaloy-2 sheet materials to examine the effects of texture, hydrogen concentration and hydride morphology on stress reorientation of hydrides. In the temperature range measured, it has been found that the threshold stress for (re)orientation of hydrides is not affected by hydrogen concentration, thermal cycling or hydride morphology precipitated before tensile test. It has been also found that the threshold stress for (re)orientation of hydrides is approximately 80 MPa. Above the threshold stress, hydrogen concentration do not affect the stress reorientation, whereas the texture of Zircaloy-2, thermal cycling and hydride morphology affect the stress reorientation. The modified Ells' equation is proposed for expressing the effect of the texture of Zircaloy-2. (author)