NON-LINEAR FINITE ELEMENT SIMULATIONS OF HYDROGEN DIFFUSION AND HYDROGEN-DISLOCATION INTERACTIONS
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Date
2015-05-11
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Johns Hopkins University
Abstract
The effect of hydrogen on dislocation-Impurity atom interactions is studied under conditions where hydrogen is in equilibrium with local stresses and in systems where hydrogen increases the elastic modulus.
The problem is investigated for the plane strain case, where the effect of hydrogen is modeled by a continuous distribution of dilatation lines whose strength depends on the local hydrogen concentration.
The iterative finite element analysis used to calculate the hydrogen distribution accounts for the stress relaxation associated with the hydrogen Induced volume and the elastic moduli changes due to hydrogen.
Modeling of the hydrogen effects on the edge dislocation-interstitial solute atom interaction is discussed using a finite element analysis and the atom interaction energies are calculated in the presence of hydrogen.
The interaction includes the effect of both the first and the second order terms of interaction energies, effects of initial concentration of hydrogen on diffused concentration near and far away from the dislocations.
The models have been employed to evaluate all effects on a single dislocation, two dislocations in a same slip planes, and randomly-distributed.
The computational scheme is compared to literature with a very good agreement.
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Keywords
Hydrogen diffusion, dislocation, interaction energy, hydrogen concentration