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MODELING MATERIALS IN EXTREME ENVIRONMENTS PERSPECTIVE FOR CERAMIC MATERIALS Ali Sayir NASA GRC and Case Western Reserve University

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Pres HfC-C UHTM Wksp 5.pptPERSPECTIVE FOR CERAMIC MATERIALS
OUTLINE 1. CURRENT APPROACH: MATERIAL SELECTION
CRITERIA
* Time scale t > hours
Role of carbon
3. EXPERIMENTAL CAPABILITIES
* Activity measurements; T>2400 °C
* Functional properties emissivity, conductivity, etc.
* Rocket testing
WC, W2C, VC, MoC, Mo2C,
ZrN, TiN
HfB, HfB2, TaB2, ZrB2, NbB2, ThO2
Refractory Metal Ceramics
SiC, B3SiLight Ceramics
ReW, Re3W, Re2Ti5,Intermetallics
Diamond, graphiteCarbon
Marginal Materials Tm << 3000 °C
Prime Materials Tm > 3000 °C
Type of Material Classification of
materials using single criteria; melting point N. J. Shaw, J. A. DiC arlo, N. Jacobson, S. R . Levine, J. A. Nesbi t t , H. B. Probst , W. Sanders and C . A. Stearns, NASA Techn. Memorandum, 100169 (1987).
E. L. C ourt right , H. C . Graham, A. P. Katz, and R . J. Kerans, R pt . No, WL-TR -91-4061, Wright Pat t erson Ai r Force Base, OH (1991).
W. B. Hi l l i g, “prospect s for Ul t ra-High Temperature C eramic C omposi t es, ” JOM (1989) 697- 704.
ADDITONAL CRITERIAS: Total vapor pressure of nitrides and borides Total vapor pressure of carbides
Material Selection Criteria ?
Total Vapor Pressure of Oxides
These data were taken from Shaw et al. [19] who compiled the data from original sources.
Critical review of the available data was not available.
ZrO2, Y2O3 and HfO2 have quite low vapor pressures; however, at 1925 °C only HfO2 has the lowest recession rate.
OUTLINE 1. CURRENT APPROACH: MATERIAL SELECTION CRITERIA
2. PERSPECTIVES -- An example: HfC
* Time scale t <1000 s * Time scale t > hours * Thermodynamic compatability of polyphase
structures; Role of carbon
* Activity measurements; T>2400 °C
* Functional properties emissivity, conductivity, etc.
* Rocket testing
SOLID STAGED COMBUSTION
1 MINUTE 1 HOUR 10 HOURS 1000 HOURS Perspective for shorter time regime for aeropropulsion systems: t < 1000 s
Functionality and immediate structural integrity
Hemispherical Reflectance
Wavelength (microns)
HfC/TaC (01N18)
Functionality: Reflectance ?
(a) (b)
(c) (d)
HfC deposition on the PC coated fiber fabrics. Higher magnification micrographs ((b) and (d)). [Run# 01N14].
Integrity: Does the oxidation reaction cause high transient thermal stresses ?
0
1000
2000
3000
4000
1 MINUTE 1 HOUR 10 HOURS 1000 HOURS
Perspective for longer time regime for aeropropulsion systems: t > hours 1. The interlayer HfCxOy is an oxygen diffusion barrier. How good is this
statement true?
2. Can models predict the adherence strength for both the residual carbide and outer oxide ?
3. The outer HfO2 contains discontinuities (pores) scaling in 0.01 µm. How efficient can they act as TBC?
4. HfO2 is one the most stable oxide. Can the phase transition can be eliminated using Ta2O5.
0
0.2
0.4
0.6
0.8
0 1 L
CO CO 2
6. Need oxygen diffusion constants ?
2.6 x 10-7
1.6 x 10-5
(a) Fracture morphology of the composite,
(b) outer surface morphology of HfC,
(c) columnar growth of high strength HfC, crystal at the start of the growth,
(d) Compliant (porous) layer,
0
10
20
30
40
50
60
ST R
E SS
, M P
The thermodynamic stability of the coexisting phases; compatiblity ?
OUTLINE 1. CURRENT APPROACH: MATERIAL SELECTION CRITERIA
2. PERSPECTIVES ; an example HfC
* Time scale t <1000 s
* Time scale t > hours
Role of carbon
3. EXPERIMENTAL CAPABILITIES
* Phase diagram study; T > 3500 °C * Activity measurements; T>2400 °C * Functional properties emissivity, conductivity, etc. * Rocket testing
(1) PHASE DIAGRAM STUDY
He- Ne
LA SER
VACUUM CHAMBER
2
INFRARED TEMPERATURE SYSTEM MEASURES AND CONTROLS THE TEMPERATURE OF THE MOTION ZONE. He-Ne LASER SYSTEM
MEASURES AND CONTROLS FIBER DIAMETER.
FIBER
CD-88-37299
and Ta2O5
< 0.0001 % Ca
0.0001 % Mg
99.997 % pure
Cerac Inc.
Experimentally determined phase diagram and hypothetical phases (solid lines) in the Ta2O5 – HfO2 system
1000
1500
2000
2500
3000
M el
ti n
g P
o in
"effective concentration"
solution phase and reference state
ii)i( Xa =
measure pressure ratio as function ( measure pressure ratio as function ( comp.comp., , TT ) )
(2) THERMODYNAMIC DATA
Multiple effusion-cell vapor source
• Pressure range: 10-9 – 10-4 atm. -- temperature range: 1000 – 2500K (depending on p(i))
• Include primary temperature reference(s) (Tmp(Au)…) accurate temperature measurements
• Determine phase transformations
Al-O, Ti-Al-O, Zr-Al-O, Ni-Al-Pt-O and Nb-Ti-Hf-Si
Pt effect on -NiAl / Al2O3
1.1515.039.545.4B
1.E-04
1.E-03
1.E-02
1.E-01
1/T
and 75-175
• Chamber Pressure
- round hardware,100-1000psia
• Coolants – H2O, GH2, N2
• Max coolant pressure, 1200psi
• Max coolant flow, 300gpm
propellant supply required - up to ~ 9 min
for low Pc and H2O requirements
• Cumulative Run Time per Day –
Determined by O/F and Pc, ~ 30 mins per
trailer
(3) REALISTIC TEST CONDITIONS: Cell 22 - Facility Cell 22 - Facility CapabilitesCapabilites
(H2O)
(H2O)
Cell 22 Cooled Panels Set UpCell 22 Cooled Panels Set Up
Nozzl
e
Injector
Validation in Engine Testing
Validation in Engine Testing
IHPRPT and ALCAN Programs
•H2 coolant
• ACCEPTABLE MATERIAL SELECTION CRITERIA
• PREDICTIVE MODELING IN LARGER TIMES SCALES
• THERMODYNAMIC DATA AND REALISTIC TEST CONDITION