International Hydrogen Conference (IHC 2012): Hydrogen-Materials Interactions
77 Multi-Field Modeling of Hydrogen Transport and Fracture in Group 4 Transition Metals
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This work deals with a computational model for hydrogen transport, hydrogen induced deformation, embrittlement and fracture in hydride forming metals, notably Ti and Zr. The model uses a continuum description of the two-phase (α-phase metal plus δ-phase hydride) material, and solves the multi-field partial differential equations for temperature- and stress-directed hydrogen diffusion together with mechanical equilibrium in a three-dimensional finite element setting. Point-kinetics models are used for metal-hydride phase transformation and stress-directed orientation of hydrides, while a cohesive zone fracture model caters for initiation and propagation of cracks. The model as a whole is versatile and can be used to study a wide range of problems and conditions involving transport of hydrogen by directed diffusion in combination with hydride precipitation and fracture. The applicability of the model is demonstrated by simulations of fracture tests on a hydrogen-charged Zr-Nb alloy.