Multiscale multiphysics model for hydrogen embrittlement in polycrystalline nickel

摘要

A multiscale multiphysics model has been developed to investigate hydrogen embrittlement in polycrystalline nickel. Appreciation of the role that hydrogen and residual stresses play in hydrogen embrittlement of polycrystalline metals has led the authors to propose a coupled microstructural and continuum approach to the simulation of the chemo-mechanical process. Within a macro scale finite element model the macro domain is replaced at critical defect sites with a microstructural domain. Resolution of the different microstructural material characteristics within the grain, grain boundary and triple junction points, including grain orientation can be used to improve the predicted distributions of both hydrogen and stress within the microstructure. The results show that microstructural features of polycrystalline nickel play an important role in the segregation of hydrogen which may lead to hydrogen induced crack initiation and development. Computational analyses are presented to demonstrate the application of the model in an attempt to bridge the gap between the micro and macro length scales for the chemo-mechanical problem in the case of a small, pre-placed nano-crack in a loaded plate in a hydrogen rich environment. (C) 2014 Elsevier B.V. All rights reserved.