The finite element method is used to solve the coupled large strain elasloplasticity boundary value problem and transient hydrogen diffusion initial boundary value problem. As an example, solutions are obtained in the neighborhood of a rounded notch in a 4-point bend specimen of alloy X-750 at two temperatures under plane strain deformation conditions. The model accounts for the dilatational strain caused by the presence of hydrogen in the lattice and the hydrostatic stress induced drift of hydrogen. The hydrogen population profiles in both normal interstitial lattice sites (NILS) and trapping sites are calculated and conditions for the predominance of the total amount of hydrogen by either of the populations are studied. The competition between hydrostatic stress and plastic strain in the enhancement of local hydrogen concentrations is investigated. The effect of different types of traps on the relative level of trapped hydrogen as a portion of the total hydrogen is examined, The numerical analysis in conjunction with current experimental evidence suggests a specifically designed line of experiments that will isolate the parameters crucial to hydrogen induced material degradation in X-750. (o 1998 Elsevier Science Ltd. All rights reserved.
All Science Journal Classification (ASJC) codes
- General Materials Science
- Mechanics of Materials
- Mechanical Engineering