A micromechanics approach to the study of hydrogen transport and embrittlement

The mechanisms of hydrogen related fracture are briefly outlined. Previous investigations on the physics and treatment of the hydrogen transport processes are reviewed. A hydrogen diffusion model based on the interaction of hydrogen induced strain in the lattice with local material elastoplasticity is presented. Finite element studies were carried out to analyze the hydrogen distribution in the neighborhood of a blunting crack tip under small scale yielding conditions and in the neighborhood of a rounded notch in a four-point bend specimen. The calculated hydrogen concentration profiles and experimental observations of embrittlement in high strength steels are used to make evaluative statements on the occurrence of the first microcracking event. (C) 2001 Elsevier Science Ltd. All rights reserved.