Strain evolution of zirconium hydride embedded in a Zircaloy-2 matrix

Measurement and modeling of strain fields in zirconium hydrides precipitated at a stress concentration

“…This value is in reasonable agreement with the observation of apparent residual tensile strain of $3.2 Â 10 À3 for the 'cracked' hydrides mentioned above -in fact they thus show a 'true' residual strain of $À2.4 Â 10 À3 indicating partial relaxation of the initial formation strains. This interpretation is also in reasonable agreement with the observations of Kerr et al [37] from a tensile test on hydrided zirconium; their data suggested a tensile strain in the hydrides (relative to the 'as-precipitated' state) of around 5 Â 10 À3 when fracture was deemed 'significant'. Despite these potentially useful observations, the validity of the hydride powder for serving as a reference for the hydrides in the Zr-2.5Nb pressure tube material in this experiment must be considered.…”

Fracture Strength of Embedded Hydride Precipitates in Zirconium and its Alloys

“…9.3) and were identified from their diffraction data as being d hydrides. Unlike the single d-hydride peak observed from only the reflections of {1 1 1} planes by Kerr et al [28], Steuwer et al [48] were able to observe three d-hydride peaks corresponding to reflections from the {3 3 1}, {1 1 3}, and {2 2 0} d-hydride planes, but no peak was observed from the {1 1 1} d-hydride planes as found by Kerr et al [28]. The reason for the different observations likely is because the range of d-spacing over which diffraction data were obtained differed between the two studies.…”

“…A similar set of tests as those done by Kerr et al [28] were also carried out by Steuwer et al [48], using slightly different zirconium material, specimen geometries, and experimental conditions. The specimens used by Steuwer et al [48] were prepared from material cut from Zircaloy-2 and -4 fuel cladding tubes.…”

“…Results of such tests on zirconium alloys with embedded hydride precipitates have recently appeared in the literature and are described in the following. Kerr et al [28] were one of the first to apply synchrotron X-ray diffraction methods to the mechanical deformation of zirconium alloy specimens containing hydride precipitates. For these tests, a slice of dimensions 2.25 9 30 9 60 mm 3 was machined from a warm-rolled Zicraloy-2 slab having 20 lm grain size.…”

“…9.11 Comparison of results from FE calculations and experimental data for both phases under applied tension. The specimen is loaded along the TD direction, with the RD direction perpendicular to the applied load (from Kerr et al [28]) matrix in the model was obtained from experimental results of tensile tests of non-hydrogenated Zircaloy-2 plate material. Comparison of the model predictions with the experimental results, which also include the average lattice strain data for the a-Zr matrix in addition to those for the d-hydrides, is given in Fig.…”