The effect of applied stress on the accommodation energy and the solvi for the formation and dissolution of zirconium hydride

International Conference on Hydrogen Effects on Material Behaviour and Corrosion Deformation Interactions, Moran, WY, 22-26 September 2002Using an axi-symmetric finite element model, the elastic-plastic accommodation energy of a penny-shaped hydride precipitate in a zirconium alloy matrix is calculated as a function of externally applied loads. The calculations are based on a previously developed approach in which the starting point of the calculation of the accommodation energy for hydride dissolution is the plastically deformed hydride. Expressions are provided showing how the hydrogen solvi are affected by the accommodation energy for hydride precipitation and dissolution when the solid is subjected to different combinations of external stress or there exists a region of high stress in the material, such as at a crack under tensile loading. The calculations of the accommodation energy show that only a deviatoric stress affects the accommodation energy. However, the effect is not large for the range of yield stress values of practical interest. This means that solvi relations derived experimentally in unstressed solids can be used to a good approximation to determine the conditions at which hydrides will precipitate at, for instance, crack tips.Department of Mechanical Engineerin