Mechanical Characterization of Zirconium Hydrides with High Energy X-Ray Diffraction

Abstract

Zirconium and its alloys are of technical importance, finding application as a structural material in the nuclear industry. Engineering components fabricated from zirconium slowly pick-up hydrogen as a result of in-reactor corrosion, degrading the components mechanical properties as a brittle hydride phase forms. This dissertation applies high energy X-ray diffraction to directly measure the mechanical properties of zirconium hydrides in the bulk and at stress concentrations in zirconium alloys. The current study is presented as a manuscript format dissertation comprised of three manuscript chapters. Chapter 3 reports the in-situ loading of hydrided Zircaloy-2 and discusses hydride/Zircaloy-2 matrix interactions as a function of applied load. Chapter 4 reports the mechanical behavior at a fatigue pre-crack in un-hydrided Zircaloy-2, comparing the results to finite element and polycrystalline plasticity models of the crack tip. Chapter 5 reports the effect of hydrides on the notch tip strain field. The three manuscript chapters are followed by a general discussion in Chapter 6 and conclusions in Chapter 7.