Fundamental Challenges inFundamental Challenges inMultiscale Materials Modeling and SimulationMultiscale Materials Modeling and Simulation

Sidney YipSidney Yip

Nuclear Science and Engineering and Materials Science and EngineeringNuclear Science and Engineering and Materials Science and EngineeringMassachusetts Institute of TechnologyMassachusetts Institute of Technology

National Synchrotron Light Source WorkshopCharacterization of Advanced Materials under Extreme Environments

for Next Generation Energy SystemsBrookhaven National Laboratory, September 25, 2009

DOE Workshop onBasic Research Needs for Advanced Nuclear Energy Systems, July 2006

Identify new, emerging, and scientifically challenging areas in materials and chemical sciencesthat have the potential for significant impact on advanced nuclear energy systems

The fundamental challenge:Understand and control chemical and physical phenomena in multi-component systems from femto

seconds to millennia, temperatures to 1000ºC, and radiation doses to hundreds of displacements per atom.

Enormous and broad implications in the materials science and chemistry of complex systems:New understanding is required for microstructural evolution and phase stability under extreme chemical

and physical conditions, chemistry and structural evolution at interfaces, chemical behavior of actinide and fission-product solutions, and nuclear and thermo-mechanical phenomena in fuels and waste forms.

First-principles approaches are needed to describe f-electron systems, design molecules for separations, and explain materials failure mechanisms. Nanoscale synthesis and characterization methods are needed to

understand and design materials and interfaces with radiation, temperature, and corrosion resistance.

New multiscale approaches are needed to integrate this knowledge into accurate models of relevant phenomena and complex systems across multiple length and time scales.

The fundamental challenge:

Understand and control chemical and physical phenomenain multi-component systems

from femto seconds to millennia,

temperatures to 1000ºC,

and radiation doses to hundreds of displacements per atom.

DOE Workshop on Basic Research Needs for Advanced Nuclear Energy Systems, July 2006

Structure – Property Correlation

Unit Process to Functional Behavior

Concept Materials

Role of Experiments

Fig. 1-2

Modeling and Simulation across length/timescales, from electrons, atoms to the continuum

Dynamics of Metals – a large multiscale modeling ASCI program at the Lawrence Livermore National Laboratory

Fig. 1-4

Unit Process in Mechanical behavior

ideal shear strength (nano-indentation)tensile failure (soft mode instability )

charge density redistribution (affine shear deformation)water-silica reaction (hydrolytic weakening)dislocation nucleation (crack tip plasticity)

many properties (structural, thermal, transport, etc.) can be studied

J. Li, “Physics and Mechanics of Defect Nucleation”, MRS Bulletin 32, 151 (2007)

Nanoindentation in 2D (MD): von Mises Stress Invariant DistributionNanoindentation in 2D (MD): von Mises Stress Invariant Distribution

Nonlocal instability criterion for homogenous nucleation of a dislocationJ. Li et al., Nature 418, 307 (2002)

( , ) ( ) 0ijkl i k jl j lw k C w w k k

soft phonons

Charge density redistributions in affine shear ideal shear strength of two fcc metals

S. Ogata et al, Science 298, 807 (2002)

Cu Al

Al

Cu

H2O + Si-O-Si 2SiOH

attack of water molecule on quartz (SiO2)

T. Zhu et al., J. Mech. PhysSolids 53, 1597 (2005)

Transition state pathwaysampling (NEB)

Molecular orbital theory

Stress-dependentactivation barrier

minimum energy path

from unit processes at the atomistic level tosystems behavior at the meso/macro-scale

__________________________

‘Concept Materials’

virtual prototypes -- all-atom models capable of predicting functional behavior in extreme conditions

Transform existing technology from empirical practice to science based

Oxidation resistance of a UHTC (ZrBOxidation resistance of a UHTC (ZrB22) depends critically) depends critically

on oxygen transport across a protective complex oxide layeron oxygen transport across a protective complex oxide layer

Monteverde and Bellosi, J. Electrochem. Soc. 150 (2003) B552

Borosilicateglass layer

ZrO2

unreacted ZrB2

SiC

Understanding the kinetics of hardening in cement paste

Shear modulus of slurry (water-cement =0.80 w/w) measured by ultrasonic attenuation showing coagulation and setting stages [Lootens et al. (2004)]

Mechanism ?

Molecular Model of Cement?

MD model of mineral-solution interface,30 A aqueous layer with Cl-, SiO4

2-, and Na+

[Kalinichev et al. (2006)]

Schematic of cement paste showing dissolution of C3S and precipitation of C-S-H platelets in a solution of Ca(OH)2 and Ca2+ and other ions [Jönsson et al. (2005)]

C3S = Ca3-SiO5 C-S-H = CaO-SiO2-H2O

Can such a model describe cement hardening ?

Molecular model of C-S-H Ca/Si = 1.7, ρ = 2.48 g/cc

Pellenq et al., PNAS 2009

“Designing radiation-resistant materials for extreme environments requires development of

computational models valid from angstroms and picoseconds to millimeters and years and

beyond…

Also required are new experimental capabilities to provide model input and test

model predictions”

“Structure-Property-Performance” correlation

is key to the

integration of experiments with modeling and simulation

Current series of DOE workshops on extreme computing and grand challenges(May, August, Octobert 2009)

NEAMS (Nuclear Energy Advanced Modeling and Simulation)(March, October 2009)

Energy Innovation Hub(s)(Nuclear Reactor Modeling and Simulation, Energy Storage, Solar)