HIGH TEMPERATURE

AEROSPACE MATERIALS 17 March 2011

Dr. Ali Sayir

Program Manager

AFOSR/RSA

Air Force Office of Scientific Research

AFOSR

Distribution A: Approved for public release; distribution is unlimited. 88ABW-2011-0790

2

2306 PORTFOLIO OVERVIEW

NAME: HIGH TEMPERATURE AEROSPACE MATERIALS

BRIEF DESCRIPTION OF PORTFOLIO:

Scientific leadership to enable revolutionary advances for the high temperature materials:

• Ceramics

• Metals

• Hybrids (including composites)

LIST SUB-AREAS IN PORTFOLIO:

• Conventional Materials Processing

• Bulk Metallic Glasses

• High Temperature Actuators

• Wear Resistant Materials

• Geopolymers

• Experimental and computational tools to address the complexity of combined external fields.

• Multi-modal diagnostics that validates the fidelity of simulations.

• In-situ characterization methods for at extreme environment.

• 3-D Structure Description – Tomography

• Mathematics to quantify microstructure.

• Theoretical and/or computational tools that aid in the discovery of new materials

• Nontraditional synthesis of materials and nanostructures by external electric field, lasers, etc.

• Transparent ceramics (interface science).

• Radiation reflection, catalytic response (surface science ) and acoustic Mitigation.

TREND

3

Scientific Challenges

- Understand physical, chemical and structural challenges:

• Design and understand hierarchical structure

• Discovering new materials that exploits C-rich amorphous oxides

- Predict responses of materials under thermomechanical extremes:

• Understanding of materials under static, quasistatic, and dynamic thermomechanical extremes

• Property gradient measurements

• Electronic information of atomic species

• Fully exploit 3-D structure information

• Simulated damage evaluation and validation

- Deformation characteristic of bulk metallic glasses:

• Spatial electron density

- High temperature or high pressure phase transformation:

• Study materials in situ as the defects originate and evolve; T> 1900 C.

• Extending understanding of plastic deformation from mano to macroscale

- Eye-Safe Polycrystalline Lasers: Sesquioxides - Sc2O3

• Solving supersaturation problem and design interface structure to achieve superior lasing

Mathematics of microstructure :• Quantification of heterogeneous structures

• Identifying sample distributions of shape descriptors

Create new foundations for new technology and solve formerly unsolveable Challenges

4

Transformational Opportunities

PI – Dr. J. Ballato / Clemson University:

High Energy Laser Multi-disciplinary Research Initiative (JTO HEL MRI / AFOR).

Transitioning to ARMY.

PI – Dr. M. Pascucci / CeraNova Corp – STTR:

Aerodynamic Hypersonic Dome: Transparent, polycrystalline alumina

Transitioning to Eglin AFB.

PI – Dr. W. Kriven / UIUC:

Geopolymer has 3-D structure analogous to zeolite but 1500 C capability.

Transitioned to Tyndall AFB – 6.2 Funding

PI – M. Uchic / AFRL – RXLM – LRIR:

Microtesting: Meso-scale‘ size effects and spatial property mapping.

Transitioned to Academia

PI – Dr. Alp Sehirlioglu / CWRU:

High Temperature Piezoelectric Ceramics.

Transitioned to NASA – High temperature Actuator for Fuel Modulation.

5

Materials and Structures for Propulsion

Flowpath

Sharp leading edges

-Very high heat flux, small area

-Active cooling/heat pipes possible,

not preferred

UHTCs

- very high T, high conductivity

- very poor oxidation resistance

Flowpath surfaces

Large area: weight critical

Active cooling in some regions

CMCs:

x3 weight reduction c.f. metals

Reduced heat flux absorbed

~2000

C

Cowl Leading Edge

Free-Stream Mach 8

Blunt LE,

Sustained hypersonic flight at high Mach No.

- High heat flux & heat loads

- High T, oxidation, shear, erosive conditions

- Active cooling -> very high thermal gradients

- Conditions vary with location

6

National Hypersonic Science Center for

Materials and Structures

Combine experiments

and multi-scale models

into a virtual test system

multi-scale models

new experimental methods

new materials &

processing routes

Teledyne Scientific

D. Marshall (materials & structures)

B. Cox (mechanics of materials)

UC Santa Barbara

F. Zok (structural materials)

R. McMeeking (mechanics)

M. Begley (mechanics)

U. of Texas

P. Kroll

(atomistics)

Missouri University

W. Fahrenholtz

G. Hilmas, (UHTCs)

U. of Colorado

R. Raj(high temp. materials & properties)

U. of Miami

Q. Yang

(mechanics)

UC Berkeley/ALS

R. Ritchie (mechanics, imaging)

Collaborations, test and advisory

supportAFRL/WPAFB (M. Cinibulk)

NASA, Boeing, ATK, Lockheed-Martin

Educational outreach

summer schools

co-location of students

web-based outreach

(iMechanica)

web-based tools (nanoHUB)

AFOSR: A. Sayir

NASA: A. Calomino

U. Virginia

B. Opila

7

e.g., brick

& mortar

O-barriergas flow

through nano-

micro crack

gas diffusion

stress-corrosion cracking

interfacial degradation

material

loss

Multiscale Nature of High-T CMCsD. Marshall / Teledyne Scientific

8

Loci colored lines indicate the yaw of the tows along the weave

Geometric Model FEM Converter

x-ray CT image & discrete data (UC-B)

CAE create solid

with assigned

material types &

properties (UM/TSC)

G1

G2

G3

G4

G5

G6

G1

G2

G3

G4

G5

G6

Meshing & A-FEM Analyzsis (UM)

Validation

(UC-SB)

Geometric model with explicit boundaries

after statistic analysis + discrete data or

analytical expressions (UCSB/TSC)

Constituent

microstructural features

of two woven fiber textile

composites investigated

in 3-D through the use of

x-ray micro-tomography

(micro-CT) .

segmenting tomography

data permits structural

information to be derived

in a 3-D heterogeneous

material.

Q. Yang / University of MiamiR. Ritchie/ UC Berkeley

9

Simulated Damage Evolution

Validation :

Appreciable nonlinearity in s-

e at ~ 0.2% due to matrix

cracking

Cracks tend to initiate near

locations of warp-weft tow

interlacing

Matrix cracks facilitate

debonding

Delaminatin crack wake

friction critical

Failure s and e too low – lack

of 3D tow reinforcement in 2D

modelsw

arp

weft

0

20

40

60

80

100

120

0 0.002 0.004 0.006 0.008 0.01

Nominal strain

No

min

al

stre

ss (

MP

a)

A-FEM with

matrix cracking

UCSB test

G1

G2

G5

Q. Yang / University of Miami

F. Zok / UC Santa Barbra

10

SiC/PDC/HfO2 after

1h at 1600oC

HfO2 coating

Top

surface

SiC/PDC/HfO2

(as coated)

Developed UHT Coating that protects

SiC for 1h at 1600oC in air

ZrB2-29.74 m % SiC after oxidation

Oxidation Mitigation

R. Raj / Uni. Colorado

R. Speyer / Georgia Inst. Tech.

11

Chemical Bonding by XPS

536 534 532 530 528 526

O 1s

Annealed

As-deposited

Organic

HfO2

Inte

nsity

Binding Energy, eV

800 1000 1200 1400 1600 1800 2000

HfO2

G

D

SiInte

nsity

Annealed

As-deposited

Raman Shift, cm1

800 1000 1200 1400 1600 1800 2000

GD

Annealed

As-deposited

Inte

nsity

Raman Shift, cm1

800 1000 1200 1400 1600 1800 2000

G

D

As-deposited

Annealed

Inte

nsity

Raman Shift, cm1

22 20 18 16 14

Annealed

HfO2

HfCxO

y

HfC

As-deposited

Hf 4f

Inte

nsity

Binding Energy, eV

Raman spectra films contain nano-graphitic carbon

0 100 200 300 4000.1

1

10

100

0.1

1

10

100

Natural 18

O abundance (0.2%)

Si

CHf

18O

16O

Hf,

C s

ign

al in

ten

sity,

a.u

.

18O

, 16O

, S

i re

lative

co

ncen

tra

tion

, a

t%

Depth, a.u.

18O diffusion studies confirm diffusion-barrier properties of C-

rich amorphous films. An abrupt amorphous-microcrystalline

transition on removal of carbon D. Pejakovic/ SRI

12

Surface Temperature Histories

0 60 120 180 240 300 360 420 480 540 600 6601200

1400

1600

1800

2000

2200

2400

2600

2800

SU

RF

AC

E T

EM

PE

RA

TU

RE

, K

TEST TIME, s

3.3

3.5

3.9

3.4

3.2

ZrB2-30vol%SiC-4mol%WC

1000

1200

1400

1600

1800

2000

2200

2400

2600

Mass flow: 16 g/s

Pchamber

: 10 kPa

Spontaneous

Temperature

Jump

~470 K

SU

RF

AC

E T

EM

PE

RA

TU

RE

, °C

Plasmatron Power Increase

qcw

= 40-80 W/cm2

qcw

=75-85 W/cm2

The von Karman

Institute 1.2 MW

Plasmatron

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

J. Marschall / SRI

13

Atomic Emission Lines During Temperature Jump

403 409 415 421 427 433 4392200

2250

2300

2350

2400

2450

2500

2550

2600

2650

2700

SU

RF

AC

E T

EM

PE

RA

TU

RE

, K

TEST TIME, s

ZrB2-30vol%SiC-4mol%WC

Sample 3.3

1950

2000

2050

2100

2150

2200

2250

2300

2350

2400

SU

RF

AC

E T

EM

PE

RA

TU

RE

, °C

200 250 300 350 400 450 5000

2000

4000

6000

8000

10000

12000

14000

16000

ZrB2-30vol%SiC-4mol%WC: Sample 3.3

WAVELENGTH, nm

Si

WEM

ISS

ION

IN

TE

NS

ITY

, arb

.

Boundary Layer Emission (424 s)

Air Plasma Background Emission

B

350 400 450 5001000

1200

1400

1600

1800

2000

2200

2400

2600

2800

B 249.92 nm

Si 288.16 nm

W 400.99 nm

ZrB2-30vol%SiC-4mol%WC: Sample 3.3

Plasmatron

Off

Spontaneous

Temperature

Jump

Plasmatron

Power

Increase

TEST TIME, s

SU

RF

AC

E T

EM

PE

RA

TU

RE

, K

0

3000

6000

9000

12000

15000

EM

ISS

ION

INT

EN

SIT

Y, a

rb.

Transient Atomic

Emission Signatures

J. Marschall / SRI

14

Laser Diagnostics: Property Gradients

•Collection optics are f/4 - f/6 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

Translate collection optics and beam to

measure T and species distributions

T(x)

ni(x)

xFlow

Sample

• Measurement with 207 nm

transition (f/15 optics) normalized for

pulse energy

• Temperature determined from line

widths with Treact known

• Absolute number density from

spectrally integrated signals, with

additional measurements: Raman

calibration, temporal profile, spatial

profile, lifetime

• From measured T and p: n = p/kT

• For nitrogen plasma and measured nN: nN2 = n - nN

D. Fletscher / Uni. Vermont

15

HTXRD Experimental Setup

Phase Transformation of Hafnia

In-Situ Synchrotron Studies up to 2000 C

W. Kriven / UIUC

An efficient, all-encompassing methodology, to investigate high temperature

properties and behavior of materials based on fundamental crystallographic

measurements performed in-situ at high temperatures.

16

Plasticity in High Temperature Materials: Tantalum and Monazite

Lower bound on GND density of

one effective in-plane slip system

Dislocation Tilt Walls with

Characteristic Spacing

GND Density Distribution

along Slip Direction

Distribution of Characteristic

Length Scale

Status Quo

• Traditional mechanical characterization measures response of a material system

– e.g. tensile test or nanoindentation

• Physics-based predictive models require information about the internal state of the material

Objective

• Spatially resolved measurement of state of material at the mesoscale

– Between 50 nm and 500 mm

• Physics-based variables

– Lattice rotation

– Nye tensor components

– Geometrically Necessary Dislocation (GND) Density

Outcome of Experiments

• Measure the ―length scale‖ of plastic deformation

• Distribution of characteristic spacing of dislocation structures (tilt walls)

Significance

• These experiments provide an unprecendented multiscale experimental perspective on plastic deformation

J. W. Kysar / Uni. Columbia

17

BMGs as Structural Materials

Specific

strength

= constant

0.3 0.1 1 3 10 30

metals polymers

ceramics

(compression) fiber-

reinforced

polymers

Al

Ti steels

Mg-BMG

Zr-BMG

Fe-BMG

Density, r (Mg/m3)

104

103

102

10

1

0.1

Str

ength

, s

f(M

Pa)

Ti-BMG

BMGs

0.3 0.1 1 3 10 30 10-2

0.1

1

10

102

103

Fra

ctu

re T

oughness,

KIC

(MP

am

)

metals polymers

ceramics

fiber-

reinforced

polymers Al

Ti

steels

Mg-BMG

Zr-BMG

Fe-BMG

Density, r (Mg/m3)

BMGs

• Pros: Properties: High strength (tension and compression); Large elastic range

Processing: Net shape casting; Excellent formability above Tg

• Cons: Fracture toughness ranges from reasonably tough to very brittle;

Limited tensile ductility below Tg

Amorphous metals, and new hybrid materials exhibit superior behavior at high pressures, temperatures, and strain rates offering the promise of revolutionary capabilities.

18

Ductile, Fracture Resistant Bulk Metallic Glass –

Crystalline Composites

Status Quo: Metallic glasses exhibit negligible tensile ductility due to highly localized

deformation in shear bands.

New Insight: Ductile crystalline dendrites formed in situ via thermal treatments can increase

ductility to > 10%.

Project Goal: * Understand structure and resulting properties through combination of

experiment and modeling

* Optimize performance of glass/crystalline composites

Highlight:

3D Microstructural

Characterization

K. Flores / Ohio State University & W. L. Johnson / CALTECH

New Glass Stronger

and Tougher Than Steel

(Jan. 11, 2011) —

Metallic Glass Yields

Secrets Under Pressure

(Mar. 17, 2010) —

Metallic Glass For

Bone Surgery

(Sep. 29, 2009) —

Nanoscale Structures With

Superior Mechanical

PropertiesDeveloped

(Feb. 13, 2010) —

A Plane With Wings Of

Glass?

(June 24, 2008) —

Fast-Tracking the

Manufacture of Glasses

(June 29, 2010) —

Nanostructured Material

Offers Environmentally Safe

Armor-Piercing Capability,

May Replace Depleted

Uranium

(Feb. 1, 2007) —

Chemists Look Through

Glass To Find Secrets That

Are Less Clear

(June 6, 2006) —

• A cantilever beam is

FIB milled and

serial sectioned.

• SEM images of

each slice face are

stacked and post-

processed to

produce detailed 3D

reconstructions.

• Results show, for

the first time, that

the glassy phase is

completely

continuous, even at

crystalline dendrite

volume fractions

exceeding 70%!

19

Spaepen, 1977

Steif et al, 1982t

tsoften

tss

Fre

e v

olu

me

g

v0

Steady state increase in free volume

associated with softening, flow.

―Free volume‖ is defined as the volume in excess of the ideal

glass structure.

• Defined over the entire structure, not locally.

Deformation and free volume: What is the flow defect?

Unoccupied volume

captured by the hard

sphere model

Zr atom

Cu atom

Unoccupied volume

neglected by the

hard sphere model

• Definition of ―free volume‖ is volume in

excess of the ideal glass structure.

• How is the ideal defined?

• Typically perform voronoi tesselation, define

―free‖ volume as voronoi cell less volume of

hard sphere atom core.

• What is atomic radius?

• Neither of these approaches address

connectivity of ―free volume‖

Falk and Langer, Phys. Rev. E 57, 7192 (1998).

g

K. Flores / Ohio State University

20

LEDs as flow defects

LEDs:

• regions with electron density < minimum in crystal

• ~2% glass volume at 0 K

Crystal (0 K)

Glass (0 K)

2nd, 3rd nearest

neighbors

1st nearest

neighbors

Cores

(capped)

Kathy FloresOhio State UniversityIdentify Low Electron Density regions (LEDs) in the glass structure

K. Flores / Ohio State University

21

Explore Deformation Mechanisms

Measurement of size and microstructure dependent

properties

More comprehensive data for model input

and validation

Current Limitations:-Expensive, slow, and serial sample fabrication method-Limited High Temperature Capability

M. Uchic / AFRL

Enable New Research Opportunities for Microtesting

‗Meso-scale’ size effects, spatial property mapping, high-throughput testing

22

Two-Step Sintering of Sc2O3: Effect

of T1 on transparency

A B C

T1 = 1550°C

T2 = 1400°C

T1 = 1500°C

T2 = 1350°C

T1 = 1450°C

T2 = 1300°C

T1 has strongly influence on

the microstructures and the

transparency of transparent

ceramics.

A B C

Grain size 0.53m Grain size 0.42m Grain size 0.33m

Eye-Safe Polycrystalline Lasers: Sc2O3

J. Ballato / Clamson University

Critically need on-shore academic and industrial R&D capabilities for highly transparent polycrystalline laser hosts operating at eye-safe wavelengths for a series of directed energy applications.

23

0

10

20

30

40

50

60

70

80

90

0 500 1000 1500 2000 2500

Wavelength (nm)

% T

ran

sm

issio

n

44-042M

44-050E

0

10

20

30

40

50

60

70

80

90

2500 3500 4500 5500 6500

Wavelength (nm)

% T

ran

sm

issio

n

44-042M

44-050E

TWO STTR SUCCESSES

Machining:Microstructure-based

property modeling

(strength, creep):

Location-specific grain

size, precipitate

distributions resulting

from processing

Location-specific

microstructure variables

are carried over from

process to process and

evolve during each step

Location-specific

microstructure produces

location-specific material

properties

Microstructure-based location specific properties (strength, creep)

influence overall part performance during simulated spin pit tests:

Low speed testHigh speed test

0

20

40

60

80

100

0 0.1 0.2 0.3Time (sec)

Max.

Prin

cip

al S

tress (

ksi)

Without

tangentia

l force

With tangential force

Tangential

acceleration

(X100)

Low g’ volume

fraction

High g’ volume

fraction

Little distortion

Improved Centrifugal Force Calculations

Improve Spin Pit Test Predictions:

Aerodynamic Hypersonic Domes

M. Pascucci / Cera Nova Corp X. Wu / Scientific Forming Corp.

24

• Fundamental and integrated science for the discovery of materials for AF aerospace concepts.

• Breakthrough research of materials response to combined loads.

• surface phenomena from the atomic scale up through the macro scale;

• physical and chemical processes by which such materials can be modified,

• predict response through multi-scale modeling efforts,

• multi-modal diagnostics that validates the fidelity of simulations.

• Quantification of microstructure that can revolutionize the design and performance.

SUMMARY AND PERSPECTIVE

Registration | Agenda | Hotel Information | Invitation

http://www.anadarko-industries.com/AFOSRConferences/EventCalendar/tabid/100/Default.aspx