Abstract
The role of hydrogen in hydrogen embrittlement, stress corrosion cracking and hydrogen induced cracking has been largely determined. The hydrogen cracking problem in metallurgical fields has been studied for many years. In spite of that, it is still not possible to explain exactly how the presence of hydrogen within the metal structure leads to hydrogen embrittlement and crack formation. Hydrogen-enhanced localized plasticity (HELP) is an acceptable mechanism of hydrogen embrittlement and hydrogen-induced cracking in materials. In the present work, a finite element analysis is implemented to estimate the large deformation elasto-plastic behavior of the material in conjunction with the hydrogen diffusion analysis results. Hydrogen is highly mobile and can diffuse through the crystal lattice dissolving into its interstitial sites. It is necessary to assume the model which can describe the hydrogen diffusivity near the blunting crack tip as well as the large deformation phenomena. Finite element analysis is here employed to solve the coupled boundary-value problem of large strain elasto-plasticity and equilibrium hydrogen distributions ahead of a blunting crack tip by taking into consideration the effect of hydrogen on local flow stress.
