Computational modelling of full interaction between crystal plasticity and oxygen diffusion at a crack tip
Farukh Farukh
Liguo Zhao
N.C. Barnard
M.T. Whittaker
G. McColvin
2134/27418
https://repository.lboro.ac.uk/articles/journal_contribution/Computational_modelling_of_full_interaction_between_crystal_plasticity_and_oxygen_diffusion_at_a_crack_tip/9561710
Oxidation-promoted crack growth, one of the major concerns for nickel-based superalloys, is closely linked to the
diffusion of oxygen into the crack tip. The phenomenon is still not well understood yet, especially the full
interaction between oxygen diffusion and severe near-tip mechanical deformation. This work aimed at the development
of a robust numerical strategy to model the full coupling of crystal plasticity and oxygen diffusion in a
single crystal nickel-based superalloy. In order to accomplish this, finite element package ABAQUS is used as a
platform to develop a series of user-defined subroutines to model the fully coupled process of deformation and
diffusion. The formulation allowed easy incorporation of nonlinear material behaviour, various loading conditions
and arbitrary model geometries. Using this method, finite element analyses of oxygen diffusion, coupled
with crystal plastic deformation, were carried out to simulate oxygen penetration at a crack tip and associated
change of near-tip stress field, which has significance in understanding crack growth acceleration in oxidation
environment. Based on fully coupled diffusion-deformation analyses, a case study was carried out to predict
crack growth rate in oxidation environment and under dwell-fatigue loading conditions, for which a twoparameter
failure criterion, in terms of accumulated inelastic strain and oxygen concentration at the crack tip,
has been utilized.
2017-11-15 10:56:14
Full coupling
Oxygen diffusion
Crystal plasticity
Finite element method
Crack growth rate
Mechanical Engineering not elsewhere classified
Mechanical Engineering