Dislocation modelling of the plastic relaxation and thermal ratchetting induced by zirconium hydride precipitation

• DOI: 10.1016/j.jmps.2022.104988
• Publication Date: 2022-06-17T06:50:12Z
• Authors: Luca Reali; Daniel S. Balint; Mark R. Wenman
• Keywords: Zirconium alloy; Stress relaxation

The precipitation of hydrides in zirconium alloys is accompanied by a significant and anisotropic volumetric expansion. Previous literature quantified the misfit both theoretically experimentally, but these values differ greatly; experimental are consistently lower. One possibility that measurements include effect dislocations generated hydride, which relax transformation stresses. To test this hypothesis, it important to determine stress field hydride its associated dislocations, combined. A simple planar dislocation model was developed hydride—dislocation ensemble α-Zr. By capturing details structures given literature, shown study including interfacial largely reconciles predicted values. Discrete plasticity then used diffuse plastic relaxation with formation. effects on equilibrium hydrogen profile, hence implications for subsequent precipitation, discussed. In particular, precipitation–dissolution cycles were simulated calculate magnitude residual hydrostatic tension, argued be primary cause "memory effect" re-precipitation γ δ hydrides.