Materials and
and Structures
Structures for
for Aerospace
Aerospace
Materials
Propulsion Systems
Systems
Propulsion
Scramjets
Rocket
X-43b
Aeroturbine
Image courtesy of ATK
High By-pass Aeroturbine
Air flow
http://www.aip.org/tip/INPHFA/vol-10/iss-4/p24.html
Scramjets integrate air and space by Dean Andreadis
Efficiency of Various Propulsion Cycles:
Specific Impulse (Thrust/weight)
8000
Hydrogen Fuel
Hydrocarbon Fuels
Turbojets
6000
Rocket
RBCC
Isp
TBCC
Ramjets
4000
Scramjets
Turbojets
2000
Ramjets
Scramjets
Rockets
0
0
10
MACH NUMBER
20
Specific Fuel Consumption for Various Concepts
10
Conventional Rocket
9
7
Turbine Engines
TSFC (Lbm/Lbf/Hr.)
8
6
5
4
Scram/Rocket
Ramjet Take Over
3
Rocket Off
2
1
Ram/Scram Operation
0
0
Hydrogen Fuel
1
2
3
4
5
6
7
8
Flight Mach Number
9
10
11
12
Fuel Efficiency In the Aero-turbine Industry:
JT3C
Turbojet
Low Bypass
Turbofan
2nd Gen High Bypass
Turbofan
High Bypass
Turbofan
JT3D-1
Specific Fuel
consumption
CJ805
JT8D-9
JT8D-217
TAY 620
JT9D-7A
JT9D-3A
CFM56-2
CF6-6D
RB-211-524D
JT9D-7R4G2
CF6-80A
V2500 A1
CFM56-5A
BR 715
RB-211-535E4 CF6-80C2-B6F
CFM56-5C4
CF6-80E1-A2
PW4168
PW4098
PW2037 PW4056
PW4084
TRENT 895
GE90-85B
GE90-115B
R. SHAFRICK, GE Aircraft Engines
1950
1960
1970
1980
1990
Certification Date
2000
2010
2020
Engine Temperature Trend
GE90-115B
Gas Temperature, FRT
GE90-94B
Trent 892
CFM56-5C4
GE90-90B
Trent 772
CFM56-5C2
V2533 CFM56-7B
CF6-50E2
CF6-80C2A5
PW 4062
CF6-80C2D1F
CFM56-2B
CF34-8C1
BR 710
CFM56-5A
CF6-80C2B1F
JT9D
TF33
BR 715
CF6-80E1
PW 2037
CF6-80A3
CF34-10
PW 6024
CFM56-3C
CF6-50E
Trent 556
PW 4090
CFM56-5B
CF34-3B
CF34-3A
CFM56-3B2
CF6-80C2A1
CFM56-3B1
JT8D-219
RB 211
62
64
66
68
70
72
74
76
78
80
82
84
86
88
90
92
94
Engine Certification Date
96
98
00
02
04
06
08
10
12
Role of Airfoil Materials
CMCs
Increased
Temperature
Capability(K)
1600
ed
c
n
va
d
A
m
er
h
T
a
ar
B
l
st
y
rS
e
ri
1300
em
s
GEN4
GEN3
Superalloys
GEN2
GEN1
1000
1985
1990
1995
2000
2005
Introduction Date
Turbine Airfoil Material Advancements
Specific Strengths of Metallic Systems
Superalloys &
Refractories
More High Temperature Materials
Role of Airfoil Materials
CMCs
Increased
Temperature
Capability(K)
1600
ed
c
n
va
d
A
m
er
h
T
a
ar
B
l
st
y
rS
e
ri
1300
em
s
GEN4
GEN3
Superalloys
GEN2
GEN1
1000
1985
1990
1995
2000
2005
Introduction Date
Turbine Airfoil Material Advancements
Superalloy Turbine Air Foils
Equiaxed (EQ)
Dir. Sol. (DS)
Single Xtal (SX)
Ni Superalloy Improvements
1020
980
960
940
920
ΜΞ4
1988
Ν6
Ρ142
1984
Ν5
Ν4
Ρ80Η
880
Ρ125
900
Ρ80
Temperature Capability - °C
1000
860
840
1969
1972
1982
1989
1994
2000
Year of Introduction
ASM-TMS NY042198
16
Modeling at the scale of the grains
Single crystal turbine
blade
Role of Airfoil Materials
CMCs
Increased
Temperature
Capability(K)
1600
ed
c
n
va
d
A
m
er
h
T
a
ar
B
l
st
y
rS
e
ri
1300
em
s
GEN4
GEN3
Superalloys
GEN2
GEN1
1000
1985
1990
1995
2000
2005
Introduction Date
Turbine Airfoil Material Advancements
Airfoil Technology
Technology
Airfoil
H
Tra eat
nsf
er
High Performance Coating Systems:
Enabling technology for advanced gas turbines
Transverse Section
Thermal Barrier Multilayer
Al Reservoir
Nanoscale Porosity
Deposition Effects
Effects on
on Microstructure
Microstructure
Deposition
Airfoil Mode
Platform Mode
Interplay with
with
Interplay
Component
Component
Geometry
Geometry
• Reduced coating thickness within recess,
20 µm
2 µm
quantitatively consistent with reduction
in integrated flux due to shadowing by
corners.
• Reduced inter-columnar gap width—and
increased propensity to sintering—due
to elimination of most oblique vapor flux.
5 µm
Role of Airfoil Materials
CMCs
Increased
Temperature
Capability(K)
1600
ed
c
n
va
d
A
m
er
h
T
a
ar
B
l
st
y
rS
e
ri
1300
em
s
GEN4
GEN3
Superalloys
GEN2
GEN1
1000
1985
1990
1995
2000
2005
Introduction Date
Turbine Airfoil Material Advancements
Ceramic Matrix Composites (CMC)
CMC Combustor Liner
Cooling Air Reduction
Weight Reduction
20% NOx Reduction
CMC Vane
CMC Blade
Weight Reduction
Reduced Cooling Air
Increased Efficiency
CMC’s Reduce Weight and Improve Performance
(MI) SiC/SiC (DENSE MATRIX)
T = 1400C (Metals < 1100C)
¾High Thermal Conductivity
¾Inter-laminar Shear Strength
¾Reduced Sensitivity to Pesting
Transition duct
Nozzles
Integrally woven
CMC Structures
Alumina anchor tube in
CMC skin for pin joint
Braided SiC/SiC
Hyper-Therm Inc.
Metallic struts
with CMC skin
Angle Interlock
Sylramic/SiC
±45°
CMC Combustor
Liners
¡ Hi-Nicalon, Slurry Cast
¡ Successful Engine Testing
¡ Pre and Post Engine Test NDE
Revealed Degradation
¡ Additional Engine Testing
CMC Inner Combustor Liner After Engine Testing
CMC Combustor Liner Rig & Engine Testing Successful
CMC Applications in Utility Gas Turbines
Benefits:
• NOx reductions (50%)
• CO reductions (50%)
• Improved stability
• Life improvement
Annular Combustors
Shroud
Segments
Benefits:
• 90% cooling air reduction
• 0.2% efficiency gain
• Reduced tip clearance
These
These efficiency,
efficiency,
power,
power, and
and emissions
emissions
benefits
benefits translate
translate to
to
$M
$M in
in annual
annual savings
savings
for
for each
each installation.
installation.
Benefits:
• >90% cooling air reduction
• 0.4% efficiency gain
• Cost savings over SOA technology
Vanes
Benefits:
• 90% cooling air reduction
• Efficiency gains of >1%
• NOx reductions (50%)
Hybrid CMC Concept
The "hybrid" concept involves use of a moderate temperature (~1100° 1200°C) CMC structural member bonded to a ceramic insulating material
having good stability at 1600°C and good erosion resistance.
Hot Face Temp
1600°C
Ceramic
Adhesive
Bond Line
Temp.
1100°C
FGI Insulation Layer
~3mm
Structural CMC
~4mm
Cold Face Temp
750°C
•
•
•
Oxide fiber available
Insulating material technology available
Reduces cooling needs drastically
Role of Airfoil Materials
SiC/SiC CMCs
Increased
Temperature
Capability(K)
1600
ed
c
n
va
d
A
m
er
h
T
a
ar
B
l
st
y
rS
e
ri
1300
em
s
GEN4
GEN3
Superalloys
GEN2
GEN1
1000
1985
1990
1995
2000
2005
Introduction Date
Turbine Airfoil Material Advancements
Thermal Barrier Multilayer:
Challenging Thermo-Chemo-Mechanical System
Thermal Property Interplay
RESIDUAL STRESS IN TGO
Thermal Property Interplay
Slide 24
Thermal Barrier Multilayer:
Challenging Thermo-Chemo-Mechanical System
YSZ Compatibility
Compatibility with
with TGO
TGO
YSZ
EB-PVD on FeCrAlY substrate
1200°C
TGO
TGO
Zirconate
reactive
with TGO
As Deposited
After
100h at 1200°C
1 µm
7YSZ compatible with TGO
(no inter-phases formed)
Limit of thermochemical
compatibility ~21%YO1.5
Degradation Modes In Engines
Delay Spalling By Understanding
Mechanisms
And Adjusting Constituent
Properties
TBC spallation
80%
Impact
Damage
TBC
spallation
40%
1820 engine cycles
Step I:Identify
I:Identify All
All Mechanisms
Mechanisms Limiting
Limiting Durability
Durability
Step
Step II: Develop Models that Relate Durability to Material Properties
Example II (Intrinisc):
(Intrinisc): Failure
Failure by
by TGO
TGO Rumpling
Rumpling
Example
• Strain misfits cause cyclic
stresses that motivate
cycle-by-cycle crack
growth in TBC
• Highly non-linear:
.Requires numerical code
• Phenomena include TGO
lateral growth, thermal
expansion misfit
(martensite), cyclic
plasticity.
Swelling
Martensite
Fails at Oxide/Oxide Interface
LARGE SCALE BUCKLE: THE END OF LIFE
•WHAT HAPPENED EARLIER?
DISPLACEMENT INSTABILITY
Multi-Parameter Phenomenon:
Relevant Phenomena:
•Elongation/Thickening of TGO
•Plastic Flow of Bond Coat
•Strain Misfit of Bond Coat
Need Model
Plus
Critical Experiments
DESCRIBE CONJOINTLY
OBJECTIVE: DEVISE MECHANISM MAPS THAT SPECIFY SALIENT
NON-DIMENSIONAL PARAMETERS
UNDERSTAND THE FUNDAMENTALS
TGO
Deformation Mechanism Map
Synchotron Measurements
Synchotron Measurements
•Thermal Expansion
•Martensite
•Swelling
¾ “Soften” Bond Coat
STRAIN MISFITS: MARTENSITE TRANSFORMATION
600C
L10
41
650C
B2
41
42
43
44
45
46
47
48
49
42
43
44
45
46
47
48
49
Model
Validation: Example
VALIDATION
EXPERIMENTS:
AN EXAMPLE
1.
Elastic properties of constituents
2.
Thermal expansion mismatch between layers.
3.
Power-law creep.
4.
Reversible phase transformation in bond coat.
5.
Growth stress in TGO.
6.
Thickening and lateral growth strain in the TGO
7.
Initial Interface Imperfections
ANIMATION OF TGO DISTORTION AND ELONGATION
QuickTime™ and a
GIF decompressor
are needed to see this picture.
Model
Model
Validation:
Validation:
Balint-Hutchinson Code
TGO
BC
Transition
Transition
to GE
GE
to
Substrate
Code now in use at GE
SENSITIVITY STUDY USING MECHANISM MAP:
CAN MECHANISM BE SUPPRESSED?
USE MECHANISM MAP TO ELIMINATE RATCHETING
Interface Toughness
Becomes Key
Parameter:
NEW INTERFACE
TOUGHNESS TEST
1 ⎛ π δ⎞
⎛ π⎞ ⎛ π δ⎞
Gside = S⎝ ⎠ +2D⎝ ⎠ ⎝ ⎠
b 4b
2 4b
4
f=0.26
f=1.0
Γ = 20Jm-2
2
2
Mode I Adhesion Energy
of Metal / Alumina Interfaces
Work of Separation: Ni/Al2O3 interfaces
Expt.
Pure Ni/Al2O3 interface:
TBC Ni(Al)/Al2O3 interface:
Fracture in Alumina
Mode I toughness > 300 J/m2
Fracture at interface
Mode I toughness ~ 20 J/m2
Theo.
3.79 J/m2
1.30J/m2
6.84 J/m2
Al-termination
3.25 J/m2
O-termination
Failure Modes After Engine Test
Delay Spalling
By Understanding
Mechanisms
And
Adjusting Constituent
Properties
Two Basic
Basic Erosion
Erosion and
and FOD
FOD Mechanisms
Mechanisms
Two
I:Elastodynamic
50µm
II:Viscoplastic
50µm
Viscoplastic Domain
QuickTime™ and a
BMP decompressor
are needed to see this picture.
4
Simulations
LE
Soft at High Temperature
Erosion Threshold
Threshold Map
Map
Erosion
ELASTODYNAMIC
DOMAIN
Identify Importance of
Material Properties:
¾High Toughness
¾Soft at High Temperature