The document discusses the Air Force Office of Scientific Research (AFOSR) portfolio on aerospace materials for extreme environments. The portfolio aims to provide fundamental knowledge to enable advances in future Air Force technologies through discovering and characterizing materials that can withstand extreme environments involving mechanical, thermal, and electromagnetic loads. It covers theoretical and computational tools to aid materials discovery, physics and chemistry of materials in stressed environments, and experimental tools to address complexity from combined external fields in extreme conditions.

1. AEROSPACE MATERIALS
FOR EXTREME
ENVIRONMENTS
8 MAR 2012
Dr. Ali Sayir
Program Manager
AFOSR/RSA
Integrity  Service  Excellence Air Force Research Laboratory
9 March 2012 DISTRIBUTION A: Approved for public release; distribution is unlimited. 1

2. 2012 AFOSR SPRING REVIEW
NAME: AEROSPACE MATERIALS FOR EXTREME ENVIRONMENTS
BRIEF DESCRIPTION OF PORTFOLIO:
To provide the fundamental knowledge required to enable revolutionary
advances in future Air Force technologies through the discovery and
characterization of materials that can withstand extreme environments
(combined loads of mechanical-, thermal-, and other electromagnetic fields).
LIST SUB-AREAS IN PORTFOLIO:
• Theoretical and computational tools that aid in the discovery of new materials.
• Ceramics
• Metals
• Hybrids (including composites)
• Mathematics to quantify the microstructure.
• Physics and chemistry of materials in highly stressed environments
• Experimental and computational tools to address the complexity of combined
external fields at extreme environments.
DISTRIBUTION A: Approved for public release; distribution is unlimited. 2

3. OUTLINE
I. Physics and chemistry of materials in highly stressed
environments.
II. Theoretical and/or computational tools that aid in the
discovery of new materials for hypersonic application.
III. Informatics and combinatorial based materials
discovery
IV. Challenges, Motivations and New initiatives.
DISTRIBUTION A: Approved for public release; distribution is unlimited. 3

4. High Temperature Phase Transformations in
Oxide Ceramics
W. Kriven / UIUC
DISTRIBUTION A: Approved for public release; distribution is unlimited. 4

5. RNbO4 Phase Transformations
W. Kriven / UIUC
Z
To study the ferroelastic phase transformation in
bM cT select rare-earth niobates (Y, La, and Dy) using in-
situ methods for possible applications in shape
memory ceramics
I. Monoclinic-to-tetragonal phase transformation in
bT aM
LaNbO4, YNbO4 and DyNbO4 is second order
Y
cM M
II. Transformation temperatures:
aT Monoclinic
Tetragonal – LaNbO4 = 503º ± 18ºC
X
– YNbO4 = 867º ± 16ºC
This is a second order
– DyNbO4 = 875º ± 2ºC.
transformation having a
lattice correspondence on
I. Room temperature spontaneous strain (es)
transformation
– LaNbO4 = 6.84%
am ↔ bt
– YNbO4 = 6.33%
bm ↔ ct
– DyNbO4 = 6.48%
cm ↔ at
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6. Plasticity in Extreme Environment:
Tantalum and Monazite
J. W. Kysar / Columbia University
Objective
• High spatial resolution Accomplishments Relevance
experimental measurements of • Multiscale experimental perspective of • Will serve to inform and to
state variables that govern plastic deformation validates physics-based
evolution of elastic-plastic • Measurement of dislocation cell constitutive models
deformation at high temperatures
structures with SEM rather than a TEM Technology Transition
• Measured distribution and evolution of • Research collaborations
Technical Approach characteristic length scales of plastic – Lawrence Livermore National
deformation Laboratory
Two-dimensional indentation – Brent Adams (BYU)
Multiscale Measured Dislocation Monazite
– Metals (Ni, Ta) & Ceramics (monazite) Crystal
Measurement of Lattice Cell Structure with SW.
– Net Burgers Vector Density Growth
Rotation
– Nye dislocation tensor components
– Lower bound on Geometrically Necessary
Dislocation (GND) density
Multi-scale experiments
3 mm
– Spatial resolutions of 3 mm, 500 nm and 50 Cell size vs. GNDs Monazite
nm in overlapping regions
Micro-pillar
Multi-scale models
Tests
– Evolution of crystalline defects across
length scales
Distribution C: Distribution authorized to U.S. Government agencies and their contractors. To protect draft, planning, or other preliminary
information from premature dissemination. Other requests for this document shall be referred to AFOSR/PI.
DISTRIBUTION A: Approved for public release; distribution is unlimited. 6

7. OUTLINE
I. Physics and chemistry of materials in highly stressed
environments.
II. Theoretical and/or computational tools that aid in the
discovery of new materials for hypersonic application.
III. Informatics and combinatorial based materials
discovery
IV. Challenges, Motivations and New initiatives.
DISTRIBUTION A: Approved for public release; distribution is unlimited. 7

8. National Hypersonic Science Center for
Materials and Structures
Teledyne Scientific
D. Marshall (materials & structures)B. Cox (mechanics of materials)
UC Santa Barbara
Missouri University new materials &
F. Zok (structural materials)
processing science
W. Fahrenholtz &G. Hilmas R. McMeeking (mechanics)
(UHTCs) new experimental methods M. Begley (mechanics)
multi-scale models
UC Berkeley/ALS
Combine experiments and
U. of Colorado multi-scale models into a R. Ritchie (mechanics, imaging)
R. Raj (high temp. virtual test system U. of Miami
materials & Q. Yang (mechanics)
properties)
U. of Texas Other collaborations
Collaborations, test and von Karman Institute,
advisory support
P. Kroll J. Marschall, SRI, U. Vermont
AFRL/WPAFB (M. Cinibulk)
(atomistics) Gerhard Dehm, Leoben, Austria
NASA, Boeing, ATK, Lockheed-Martin International affiliate M. Spearing,Univ. Southampton
University of Canterbury Stepan Lomov, Kath. Univ. Leuven
(S. Krumdieck) Loughborough Univ. (UK)
M. Smart Univ. Queensland
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9. Some Target Microstructures
D. Marshall & B. Cox (Teledyne) / Zok (UCSB) & R. McKeeing & M. Begley/ Q. Yang (U. Miami) / W.
Fahrenholtz &G. Hilmas (UMR) / R. Raj (U. Colorado) / R. Ritchie (UC Berkeley) / P. Kroll (U. Texas)
National Hypersonic Science Center
1 mm 10 mm HfO2
0.1 mm Hf-PDC
GB phase
reinfiltrated Hf-PDC
in shrinkage crack
rigid scaffold
1 mm Multilayer
HfO2/PDC
CVD
SiC
fiber
tow
HfO2
HfO2
rigid network of Hf-PDC
large particles
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10. Synchrotron Imaging of Structure and Damage
R. Ritchie (UC Berkeley) / National Hypersonic Science Center
Compound visualization of statistical parameters
Tow cross
sectional
area mm
5
3-D microstructural Input to constitutive law
characterization &
calibration in virtual test
geometry generator
High temperature in situ stage (1500 oC)
Resolution < 1mm
SiC-SiC composite: RT in situ loading motor and
gearbox
to load cell and water cooling
crack
Lamp
Lamp guideway
dog-bone
dog-
X-rays sample
load cell
360 deg
thin window
Lamp 0.25 mm Al
Lamp furnace
water section
Lamp
cooling with
X-rays
active
cooling
2D tomographic slices with no load 8 octopole 1000W
IR lamps
water
cooling
and sample Octopole IR lamp
mount access arrangement
LBNL design : J.Nasiatka, A.MacDowell
J.Nasiatka,
Distribution C: Distribution authorized to U.S. Government agencies and their contractors. To protect draft, planning, or other preliminary
information from premature dissemination. Other requests for this documentrelease; distribution AFOSR/PI.
DISTRIBUTION A: Approved for public shall be referred to is unlimited. 10

11. Pipeline Exercise (3D)
R. Ritchie (UC Berkeley) / B. Cox (Teledyne) / Zok (UCSB) / Yang (U.
Miami) / D. Marshall (Teledyne) / National Hypersonic Science Center
mCT data from UC-Berkeley - Ritchie Validation from Measured surface strain
(UCSB – Zok)
3D geometric model
(UCSB & Teledyne)
2D cross-section data (UCSB & Teledyne)
0.025
0.02 Simulated surface strain
0.015
(UM – Yang)
0.01
0.005
0
0 1 2 3 4 5 6 7 8 9 10
3D FEM -0.005
Distribution C: Distribution authorized to U.S. Government agencies and their contractors. To protect draft, planning, or other preliminary
DISTRIBUTION A: Approved for public release; distribution is unlimited.
information from premature dissemination. Other requests for this document shall be referred to AFOSR/PI.
11

12. Disordered Structures
P. Kroll (U. Texas) / National Hypersonic Science Center
Amorphous Ceramics
• grain boundary phases (Hf/Zr-Si-C-O)
• models for melts (W-Si-B-O)
• synthesized “hierarchical” materials
(PDC or CVD)
T Hf-Si-C-N-O Si-C-O with “free” C
5000 • network approach (modified WWW algorithm)
• melt-quench
• DFT, ab initio molecular dynamics (VASP-code)
4000 • both approaches augmented with repeated annealing to achieve low-
energy structures
3000
2000
1000
30 ps 60 ps 90 ps 120 ps
time
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13. Structure Models : Hf-Si-C-O
P. Kroll (U. Texas) / National Hypersonic Science Center
Example: Hf-Si-C-O : 20 HfO2 + 15 SiO2 + 5 SiC + 5 C
or 15 HfSiO4 + 5 HfO2 + 5 SiC + 5 C
SiCO glass, Si52C12O80,
25mol%SiC
• DE in SiCO larger
than DE in SiO2 • Barrier 1 – 3 eV
Si-C substructure
Diffusion of O2 in SiCO glass is smaller
(sideview) than in SiO2 (if void structure is similar )
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14. Laser Diagnostics: Property Gradients
D. Fletcher / U. Vermont
Objective: Translate collection optics and beam
to measure temperature and species distributions
Flow
Gas Phase
Boundary
T(x)
ni(x)
Interface
Collection optics are f/4 –
and aperture is ~ 1mm for
30 kW ICP
•Pulse energy ≤ 0.25 mJ
with a 0.5 mm beam
diameter to avoid
complications such as
multi-photon ionization
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15. Biasing Reactions of Mo-Si-B-Alloys
D. Fletcher (U. Vermont) / J. Prepezko (U. Wisconsin) /
M. Akinc (u. Iowa) / J. Marshall (SRI Int.)
Computational estimates of Use computational results, SEM of a Mo60W15Si25 two phase
critical content – feasibility basic thermodynamics and alloy (Mo,W) ss and (Mo,W)5Si3.
assessment and define experimental results for
experimental window. analyzing the system.
(Models used – An extended Miedema (Density of states calculations from
model (semi-empirical thermodynamics) VASP, interface enthalpy values from
and ab-initio calculations using VASP, Miedema for understanding stability
with GGA potentials ) and partitioning)
MoB
Mo2B
TEMPERATURE, °C
1700
1500
T2
1300
1100
INTENSITY,
BO2  = 518.8 nm
a.u.
BO  = 404.1 nm
BCC A15 T1
RAW SIGNAL,
a.u.
B  = 249.9 nm
0 50 100 150 200 250
TEST TIME, s
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16. Electroplating Rhenium and its Alloys
S.R. Taylor / U. Texas Health Science &
N. Eliaz / Tel Aviv University, ISRAEL
Objective:
An (a)
aqueous, non-toxic
100 µm
•Understand the mechanism that governs the method for electroplating
electrodeposition of Re and its alloys. Re-Me coatings
ReO4-
Me2+ Me2+
2e- ReO3-
Me0 Me0 Re0
(a) 100 µm (b) 100 µm
Cu Cu
substrate substrate
Ni0M + ReO4- + 2H+ Ni2+M + ReO3- + H2O
Ni2+ + 2 e-M Ni0M
ReO3- + 5e-M + 3H2O Re0M + 6(OH)-
Calculations (NSF): (a) 100 µm (b) 100 µm (c) 100 µm
• Binding Energies:
Ni-Cu and Re-Cu
• Transition State
(Potential Barrier)
• Reduction Potential (Ni(II) &
Re(VII)) vs Ag/AgCl) Re-Fe Re-Co Re-Ni
Distribution C: Distribution authorized to U.S. Government agencies and their contractors. To protect draft, planning, or other preliminary
• information fromNi-Cu and Re-Cu requests for this documentrelease; distribution AFOSR/PI.
Entropy: premature dissemination. Other A: Approved for public shall be referred to is unlimited.
DISTRIBUTION 16

17. OUTLINE
I. Physics and chemistry of materials in highly stressed
environments.
II. Theoretical and/or computational tools that aid in the
discovery of new materials for hypersonic application.
III. Informatics and combinatorial based materials
discovery
IV. Challenges, Motivations and New initiatives.
DISTRIBUTION A: Approved for public release; distribution is unlimited. 17

18. Informatics and Combinatorial Based Discovery
K. Rajan / U. Iowa
Ranking and
Data Mining identification of key
High-dimensional descriptor space
Statistical Learning factors that govern
48 potential TC
descriptors Property
Six key factors affecting TC of
Ionic Size Dielectric loss BiMeO3-PbTiO3 ferroelectrics
Polarizability TC
Tetragonality PS
❖Ionic size
Bond covalency d33 ❖Pseudopotential radii
Ionic displacement
PCA
❖Bond length
Rough sets
❖Pauling
Crystal ❖electronegativity
Structure ❖Polarizing power
Crystal
Chemistry
❖Mendeleev number
We started with 48 descriptors
and down-selected them to 6
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19. High Temperature Combinatorial Nano-
Calorimetry for Materials Discovery
J. Vlassak / Harvard U.
Nano-calorimeter array
Cooling rate (K/s)
Distribution C: Distribution authorized to U.S. Government agencies and their contractors. To protect draft, planning, or other preliminary
information from premature dissemination. Other requests for this documentrelease; distribution AFOSR/PI.
DISTRIBUTION A: Approved for public shall be referred to is unlimited. 19

20. OUTLINE
I. Physics and chemistry of materials in highly stressed
environments.
II. Theoretical and/or computational tools that aid in the
discovery of new materials for hypersonic application.
III. Informatics and combinatorial based materials
discovery
IV. Challenges, Motivations and New initiatives.
DISTRIBUTION A: Approved for public release; distribution is unlimited. 20

21. CHALLENGE I: PROCESSING SCIENCE
Electromagnetic Excitation is a Means to Change Materials Properties
OLD:
• Photography is over 150 years old
• Photochromics are on stage several decades
• Photolithography, electron lithography, and ablation
are standard tools.
• Photosynthesis is nearly as old as life.
NEW:
Ability to increase materials excitation in
a controlled way (i.e., lasers and other EM).
CHALLENGES: (Conceptual framework between experiments and theory)
I. Energy localization (ionic or electronic); Electronic excited states (Non- Equilibrium).
II. Charge Localization (It does guide the energy localization): femtosecond to years.
III. The link between microscopic (atomistic) and mesoscopic (microstructural) scales.
Energy transfer (i.e., displacements do not need to occur at the site originally excited;
Photosynthesis - NOT FULLY UNDERSTOOD).
IV. Energy storage (energy sinks can delay damage and the process characteristics).
V. Charge transfer and space for public release; distribution is unlimited.
charge.
DISTRIBUTION A: Approved 21

22. CHALLENGE II:
Understanding of Non-Equilibrium Structures at different Length Scales
J. Luo / Clemson U.
Design: GB Phase Diagrams
• Fabrication protocols utilizing Discrete Thickness
appropriate GB structures to achieve
optimal microstructures 1 nm 1 nm
• Co-doping strategies and/or heat
treatment recipes to tune the GB
structures for desired performance
Ni-Bi Ni-Bi
Luo, Cheng, Asl, Kiely & Harmer, Science 333: 1730 (2011)
Nanometer “Equilibrium” Thickness
2 nm 2 nm
W-Ni Mo-Ni
Luo, Cheng, Asl, &, Kiely, In Preparation (2012)
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23. CHALLENGE II:
Quantitative Descriptors for the Interface
Two Questions:
AFOSR MURI 2012
1) Finite Atomic Size? (Drs. F. Fahroo and A. Sayir):
2) A Series of Discrete Grain Boundary Phases? Information Complexity in
Predictive Material Science
ONR MURI 2011 (Dr. Dave Shifler):
• Structure description
Atomic-Scale Interphase: Exploring New Material States
• Uncertainty quantification
• Cross-Entropy minimization
• Info complexity Management
• Machine learning
Definition of local state ?:
•Composition / activity
•Lattice orientation
•External field coupling
•Energy
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24. CHALLENGE III:
Materials Far From Equilibrium
Unsolved Problem I: Unsolved Problem II:
Surface temperature history Instability and 3D Erosion
The von Karman Institute 1.2 MW Plasmatron Ions, Neutral Gas, Plasma
Electrons, and Radiation
Induct. heat: 1.2 MW (max)
Enthalpy: 10 – 50 MJ kg-1 (for air)
Ma range: < 0.3
qstag: 10 – 300 W cm-2
Pstag : 0.05 – 0.15 atm Wall
ZrB2-30vol%SiC-4mol%WC Ions, Neutral Gas, Plasma
2600 De Gris et al., 2010 Electrons, Secondary Electrons,
2800 3.3 Spontaneous
3.5 Temperature 2400 Wall Material, and Radiation
2600 Jump
SURFACE TEMPERATURE, °C
3.9
SURFACE TEMPERATURE, K
3.4 ~470 K 2200
2400 3.2
2200 Plasmatron Power Increase
2000 Conductive Heat Loss
Dqcw= 40-80 W/cm
2
1800 Sheath formation affects both the plasma and the wall
2000
1600 I) Ions strikes:
• Sputter wall material and ejects species into plasma
1800
2
qcw=75-85 W/cm 1400
1600
1200
• Neutralization pulls electrons from the wall
1400 Mass flow: 16 g/s
Pchamber: 10 kPa • SEE that cools the plasma & deposit plasma energy into wall
1000
1200
0 60 120 180 240 300 360 420 480 540 600 660
II) Electrons strikes:
TEST TIME, s • SEE and deposit energy
J. Marshall / SRI
• Impact atomic structure of wall
470 K Temperature Jump ! Wall’s Contribution must be considered !
AFOSR BRI 2011: Materials far from Equilibrium (Drs. M. Birkan, J. Luginsland, and A. Sayir)
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25. Back up Slide
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