Abstract
As part of a wide-ranging theoretical research programme on delayed hydride cracking (DHC) initiation at stress concentrations, this paper is concerned with modelling the initiation of DHC at the tip of a sharp crack, and also the subsequent growth of the crack by a DHC mechanism. The paper focuses on the modelling of the fracture of hydrided material, based on the assumption that hydride failure requires the attainment of a critical tensile stress within the hydride; this necessitates that the hydrided region be sufficiently long that the crack tip tensile stress sufficiently overrides the compressive transformation stress associated with hydride precipitation. The theoretical analysis defines the conditions under which hydride failure occurs, with the hydrided region being confined to the plastic region at the crack tip. Furthermore, the analysis demonstrates the existence of a threshold stress intensity factor below which DHC fracture does not occur, and provides an explanation for the scatter in the distance between striations on a DHC fracture surface.
Published Version
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