Materials Performance Centre
Modeling Directions
Crystal Plasticity Modeling
Prediction of intergranular strains
and mechanical properties
• Relevant to stress corrosion
cracking in stainless steels
and Ni-base alloys
• Good expertise in
Manchester, validated by Xray and neutron diffraction
• Need parallelization to
allow larger microstructures
and studies of permutations
in reasonable timescales
Grain Aggregate Modeling
Prediction of intergranular
stresses and strains
• Relevant to stress corrosion,
and intergranular damage
mechanisms
• Expertise developing in
Manchester, using 3D
microstructure data and
diffraction-based validation
• Need to validate modeling
approaches and address
issues due to large model
size.
Damage Modeling
Prediction of microstructure
effects on damage development
• Relevant to stress corrosion
cracking, for example
• Development of current
work on crystal aggregates,
derived from tomography
• Work done so far in
partnership with other
institutes
• Need to develop further in
Manchester
Image-Based Modeling
Dimensional Change of Graphite
• Models constructed from
tomography data, with crystal
anisotropy deduced from pore
orientations
• Model validation against insitu tomography of thermal
dimensional change
• Aim to predict irradiation
induced dimensional change
• Currently limited by model size
Image Based Modeling
Issues
•
•
•
•
How large a volume do you need to
model?
What resolution mesh do you
need?
As resolution of XMT systems
improves, data sets and mesh sizes
expand
Research Needs
Example: fibre composite
Model
– Development of visualisation
methodologies
– Development of serial mesh
generation
– Any size mesh (so far up to 320 GB
data set)
– Development of parallelised FE code
– Development of XFEM
Stress Development
Grain Boundary Modeling
Prediction of Diffusion and
Segregation
• Relevant to stress corrosion
and sensitisation kinetics
• Requires molecular
dynamics methods
• Currently little expertise in
Manchester in this area, but
development of capability is
needed to support other
work
• Work being done with
collaborators
Flow Assisted Corrosion
• Iron oxidation to give Fe(II) or
magnetite Fe3O4 at the
Cbulk
2+
internal metal-oxide interface
Cs
Fe
Water
2+
Fe
• Diffusion of soluble species
• (Fe2+ and H2) across the porous
Oxide layer
2+
Fe
• Dissolution and reduction of
2+
magnetite into solution
Fe C0
Oxide
• Removal of the soluble iron
species (and hydrogen),
transported into the bulk of
the flowing solution
Steel
FACrate
 K . .([ Fe
2
] eq  [ Fe
2
]0 )
H2
H2
Other Areas
• Multiscale modeling
– Integration of microstructural models with
fracture propagation models
• Coupled modeling
– Development of crack tip chemistry
– Influence of residual stress on crack tip
deformation