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Multiscale multiphysics atomistic-meso-continuum critical dislocation method for hydrogen embrittlement

Sathiskumar Jothi Orcid Logo

14th International Symposium on Metal-Hydrogen Systems (MH2014), 20-25 July 2014, Salford, Manchester, UK.

Swansea University Author: Sathiskumar Jothi Orcid Logo

Abstract

Hydrogen embrittlement of polycrystalline metallic material such as nickel and nickel alloys in aerospace rocket launcher combustion chamber calls for efforts to develop multiscale atomic method (AM) -meso critical dislocation (MCD)-macro continuum (MC) method to understand the role of hydrogen play...

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Published in: 14th International Symposium on Metal-Hydrogen Systems (MH2014), 20-25 July 2014, Salford, Manchester, UK.
Published: Manchester,UK 2014
Online Access: http://mh2014.salford.ac.uk/cms/resources/uploads/files/MH2014%20Conference%20Brochure%20(web).pdf
URI: https://cronfa.swan.ac.uk/Record/cronfa30924
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Abstract: Hydrogen embrittlement of polycrystalline metallic material such as nickel and nickel alloys in aerospace rocket launcher combustion chamber calls for efforts to develop multiscale atomic method (AM) -meso critical dislocation (MCD)-macro continuum (MC) method to understand the role of hydrogen plays in multiphysics problem. The authors propose a coupled atomistic-mesoscale-continuum critical dislocation (CAMCD) model based on the input obtained from critical dislocation site meso scale microstructural model and atomistic simulations. Initially the individual microstructural phase properties of materials are determined from atomistic simulations by the precise relationship between mechanical stresses, strains and the diffusion of hydrogen. Then the effective properties of materials are calculated using finite element microstructural homogenization simulations with the help of heterogeneous intergranular and intragranular polycrystalline microstructural Representative Volume Element (RVE) model[1], followed by the implementation of subroutine developed using FORTRAN compiled programming language for trap model coupled with the continuum component model using Python script language. The microstructures RVE models are developed based on the real microstructural morphology and crystallographic microtexture data collected from experimental characterization of textured polycrystalline material. The critical dislocation sites of meso scale model are coupled with macro scale model using cut boundary by employing submodelling technique. The space coupled model initially solves the mechanical problem which is coupled sequentially with the chemical problem, in the form of mass transport analysis employing stress assisted hydrogen diffusion, using the finite element method. Fick‘s diffusion law is extended in finite element code by including the pressure gradient factor and trap parameters to drive the mass diffusion by means of hydrostatic stresses and trap model . The motivation of this testing investigation is to evaluate the CAMCD model and the benefits of experimental, submodel, homogenization technique to bridge the gap between atomistic, microstructural and continuum space scale for the hydrogen embrittlement problem.
Keywords: Hydrogen embrittlement; CAMCD model; atomistic simulation; FE microstructural model; nickel and nickel based super alloys; aerospace components;
College: Faculty of Science and Engineering

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