Fundamental Challenges in Multiscale Materials Modeling and Simulation Sidney Yip Nuclear Science and Engineering and Materials Science and Engineering Massachusetts Institute of Technology National Synchrotron Light Source Workshop Characterization of Advanced Materials under Extreme Environments for Next Generation Energy Systems Brookhaven National Laboratory, September 25, 2009

DOE Workshop on Basic Research Needs for Advanced Nuclear Energy Systems, July 2006 Identify new, emerging, and scientifically challenging areas in materials and chemical sciences that 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 phenomena in 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

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

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

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 Distribution Nonlocal instability criterion for homogenous nucleation of a dislocation J. Li et al., Nature 418, 307 (2002) soft phonons

Charge density redistributions in affine shear ideal shear strength of two fcc metals S. Ogata et al, Science 298, 807 (2002) CuAl Cu

H 2 O + Si-O-Si2SiOH attack of water molecule on quartz (SiO 2 ) T. Zhu et al., J. Mech. Phys Solids 53, 1597 (2005) Transition state pathway sampling (NEB) Molecular orbital theory Stress-dependent activation barrier minimum energy path

from unit processes at the atomistic level to systems 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 (ZrB 2 ) depends critically Oxidation resistance of a UHTC (ZrB 2 ) depends critically on oxygen transport across a protective complex oxide layer Monteverde and Bellosi, J. Electrochem. Soc. 150 (2003) B552 Borosilicate glass layer ZrO 2 unreacted ZrB 2 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 -, SiO 4 2-, and Na + [Kalinichev et al. (2006)] Schematic of cement paste showing dissolution of C 3 S and precipitation of C-S-H platelets in a solution of Ca(OH) 2 and Ca 2+ and other ions [Jönsson et al. (2005)] C 3 S = Ca 3 -SiO 5 C-S-H = CaO-SiO 2 -H 2 O 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)