Ceramic matrix composite (CMC) components are being developed for turbine engine applications. Compared to metallic components, the CMC components offer benefits of higher temperature capability and less cooling requirements which correlates to improved efficiency and reduced emissions. This presentation discusses a technology develop effort for overcoming challenges in fabricating a CMC vane for the high pressure turbine. The areas of technology development include small component fabrication, ceramic joining and integration, material and component testing and characterization, and design and analysis of concept components

Halbig, Michael C.

NASA Technical Reports Server

National Aeronautics and Space Administration 
Fundamental Aeronautics Program 
Subsonic Rotary Wing Project 
Ceramic Matrix Composites for Rotorcraft Engines 
Michael C. Halbig 
Task Lead 
NASA Glenn Research Center 
• 
https://ntrs.nasa.gov/search.jsp?R=20150010407 2019-08-31T08:07:32+00:00Z
Acknowledgements 
• The team for the CMC airfoil task includes: 
- Ram Bhatt, Army Research Laboratory, Cleveland, OH 
- Jay Singh, Ohio Aerospace Institute, Cleveland, OH 
- Craig Smith, Ohio Aerospace Institute, Cleveland, OH 
- Jim DiCarlo, NASA Glenn Research Center, Cleveland, OH 
- Jerry Lang, NASA Glenn Research Center, Cleveland, OH 
- Sai Raj, NASA Glenn Research Center, Cleveland, OH 
- Dongming Zhu, NASA Glenn Research Center, Cleveland, OH 
2 
Outline 
• 
• Introduction and Background Information 
- SRW Program's LCTR Vehicle Concept and the CMC Airfoil Effort 
. - Airfoil Challenges 
- SiC Based Materials 
• Key Technology Development for Turbine Airfoils in the SRW Project 
- Small Component Fabrication 
- Ceramic Joining and Integration 
- Sub-Element Testing and Characterization 
- Model Development of Relevant Stresses in the Component 
• Summary/Conclusions 
3 
SRW Large Civil Tilt Rotor Mission and Requirements . 
EIS = 2025 (2018 tech) Cruise > 300 knots 
TOGW =108k Ibm 
Payload= 90 pass. 
Engine = 4x7500HP 
Fuel = 21,000 Ibm 
Range > 1 ,OOOnmi 
@Alt. ~ best range 
Cruise L/D ~ 12 
Rotor tip speed 
650 fps hover 
350 fps cruise 
LCTR Mission: 90 passengers, range: 1000 nmi., cruise speed 300 knots, cruise alt.: 28 k-ft. 
LCTR Engine Characteristics: 
7500-8000 HP, overall pressure ratio of 30, T4: 3000°F hover and 2500°F cruise, HPT turbine 
vane will have dimension of about 1" high and 1" long. 
Comparison between the LCTR2 engine and other engines. 
Engine T4 (° F) Overall Pressure Ratio 
V22 (AE 11 07) 1740 16.7 
T700 2600 17 
LCTR2 (notional engine) 3000+ 30+ 
4 
SRW Vane Task Overview 
• 
Objective: 
• Develop technologies for CMC turbine engine components that have higher temperature capability, 
high fracture toughness, and require less cooling compared to current metallic turbine components. 
• Targeted toward the first stage vane (and then blade) of the high pressure turbine (HPT). 
• This is a technology development task rather than a component task 
• Benefits include: Reduced fuel burn, reduced emissions, lower weight, reduced cooling, and 
improved efficiency 
NASA GRC role vs. industry role: NASA GRC is focused on a cooled HPT (lower TRL) whereas 
industry may be more focused on less cooled and lower temperature components (higher TRL) in the 
low pressure turbine (LPT). GRC is focused on the engine requirements of the Large Civil Tilt Rotor 
Vehicle within the Subsonic Rotary Wing Project. 
SRW's CMC effort compared to CMC efforts in other NASA projects (FA and ERA): 
The SRW task is focused on small component fabrication and joining technology development. 
All CMC tasks within the projects coordinate with one another to ensure tasks are leveraged and there 
are no overlaps in efforts. 
Challenges: 
Fabrication of a small airfoil (1"x1"), cooling schemes, engine operating conditions (i.e. T4 > 3000F, and 
OPR > 30), and joining to fabricate the component. 
5 
Applications for CMCs in Gas Turbine Engines • 
Combustor F aps & 
liners Sea Is 
Courtesy of GE Aircraft Engines 
Benefits: 
• Enabling for high OPR engines (higher turbine inlet temperatures) -
reduce cooling air, reduce fuel burn and C02 emissions 
• Weight= 1/3 of metals and 1/2 of titanium aluminides 
• High OPR engines- higher combustor temperature- increased NOx, 
CMC combustor liner and first stage turbine vane reduce NOx 
6 
Current Metallic Vane Designs and Cooling Schemes • 
The preference in CMC 
turbine component 
development is to insert the 
CMC part in-place of the 
metallic one(s) rather than to 
drastically alter the outer 
geometry. 
For the SRW effort, the outer 
geometry is based on T-700 
class, 1st stage HPT vane. 
7 
Challenges with CMC Vanes and Airfoils 
• 
• Hot combustion gas Endcap joining Cooling channel 
High stress and 
temperature 
Cooling 
holes 
Tapered wall 
thickness at trailing 
edge 
• 
• 
. - . 
• 
. . 
Endcap joining 
• Production challenges are in fabricating the small radii, the tapered trailing edge, integrating the 
endcaps, and machining cooling holes. 
• Design and material challenges are in meeting the high stress and high temperature 
requirements, providing sufficient cooling, and having a durable high temperature coating. s 
Fabrication Process for Gen Ill SiC/SiC CMCs 
(2700° F Capability for G.T. Engines) 
Full CVI 
CMC 
SiC Fiber 
Reactor 
CVI - Chemical Vapor ilnfilitration 
• • 
••••• 
Reactor 
• 
9 
Ceramic Matrix Composite Materials 
- Melt Infiltrated (MI) SiC/SiC 
0-90 Plain Fiber 
Tow Weave 
Composite 
Cross-Section 
SiC grains and silicon within Ml matrix 
• High thermal conductivity matrix 
• Elimination of interlaminar porosity 
• No matrix micro cracking 
• 
10 
Ceramic Joining and Integration: Commercial High Temperature .... 
Ceramic Material- SA-Tyrannohex {SiC Fiber Material) 
8 Harness Satin 
Fiber Tow Weave 
Optical Micrograph 
Features 
• 8 Harness Satin Weave of SiC 
Tyranno fibers 
• Layers hot pressed together 
• Hexagonal sintered fibers 
• Nano-layer of carbon on the 
fiber surface 
SEM Micrograph 
Benefits of SiC SA-Tyrannohex 
• High fracture toughness 
• Fatigue resistance 
• Low weight and high temperature capability 
• Machinable and complex shape formation 
• Candidate material for the vane endcap 
11 
Areas Being Addressed by the SRW Vane Task 
Key Technology Development for a Turbine Airfoil 
in the SRW Project 
Subtasks: 
• Small Component Fabrication 
• Ceramic Joining and Integration 
• Sub-Element Testing and Characterization 
• Model Development of Relevant Stresses in the 
Component 
• 
12 
Small Component Fabrication 
- Objective and Concepts 1 and 2 
• Objective: Demonstrate fabrication ability of small 1 "x1" airfoils (vane cord length x height) 
Materials: SiC/SiC (w/Sylramic and Hi-Nicalon SiC fibers) CMCs, CMC/ceramic foam hybrid, SA-
Tyrannohex as a potential endcap material 
Issues: inter-laminar strength, leading edge, trailing edge, cooling channels, surface cooling holes 
Airfoil Concept 1 . Airfoil Con~ept. 2 
• Internally Cooled Vane - F1lm Cooled A1rfo1ls for 
Axial Cooling Holes 
SiC/SiC Composite 
1.25" (32mm) 
• Two airfoils sets made with different silicon carbide 
fibers (Sylramic and Hi-Nicalon-S). 
• NASA three layer EB-PVD environmental barrier 
coatings 
the Vane and Blade 
Endcap/Ring 
..-----
Section 
• 
0 Airfoil • 
0 ~ • 0 • 
0 
• 
0 Endcap/Ring 
• 
.------ Section 
Planned Sub-Element Testing for both Concepts 
- Burner rig testing with and without internal cooling 
and EBC 
- Heat flux tests with and without internal coolin~ 
3 
and EBC 
Ceramic Joining and Integration 
• Objective: Develop ceramic to ceramic (and if needed ceramic to metal joining technology) 
Materials: SiC/SiC, SA-Tyrannohex, (and superalloys) 
Approach: - Develop processing details: 
- interlayer 
- conditions: time, temperature, and duration 
-method: diffusion bonding, brazing, etc. 
- Start with ceramic to ceramic joining of simple shapes 
- Join more complex shapes 
- Characterize and test (i.e. microstructural analysis, mechanical tests, thermal 
cycling, and burner rig) 
Potential Joining Needs 
• 
"" 
• 
0 
• 
0 Joining of airfoil 
• 
0 
• 
0 
• 
and endcaps 
/ Joining of singlet vanes to form 
doublets and joining of vane 
airfoils to ring sections 14 
Ceramic Joining and Integration 
-Joining Processes 
Materials (dimensions 0.5" x 1 ") 
- Substrate: SiC/SiC and SA-
Tyrannohex 
- lnterlayers: Ti foil (1 0, 20 micron) 
and B-Mo alloy foil (25 micron) 
• Ceramic substrates were 
ultrasonically cleaned in Acetone 
for 10 minutes 
• Substrates were sandwiched 
around braze and foil layers 
Diffusion Bonding 
• Atmosphere: Vacuum 
• Temperature: Ti 1200°C, 
Mo 1400°C 
• Pressure: 30MPa 
• Duration: Ti 4 hr 
B-Mo 4 hr 
• Cool down: 2 °C/min 
• 
Joining 
lnterlayer 
Applied Load 
Materials (dimensions 0.5" x 
0.5") 
- Substrate: SiC/SiC and SA-
Tyrannohex 
- lnterlayer: pastes and tapes of 
Si-based eutectics 
Brazing 
• Atmosphere: Vacuum 
• Temperature: 1340°C 
( 1 0°C above the braze 
liquidus temperature) 
• Load: 100 g/sample 
• Duration: 10 minutes 
• Cool down: 2 °C/min 
• Mounted in epoxy, polished, and / 
joints characterized using optical 
microscopy and scanning electron 
microscopy with energy dispersion 
spectroscopy analysis 
15 
Ceramic Joining and Integration - Diffusion Bonding •. 
with 10 tJm Ti Foil and 25 tJm B-Mo Alloy Foil 
SA-Tyrannohex I Ti I SA-Tyrannohex 
.Joint 
·-----
Percents are atomic o/o 
SA-Tyrannohex I B-Mo alloy I SA-Tyrannohex 
.Joint 
·----~--1 58.34% 41.66o/o 
Percents are atomic 0/o 
Oo/o 
3.19o/o 
0°/o 
Very good quality bonds are obtained that are uniform and crack free. 
However, the joining process requires high applied loads and flat sub-elements for joining. 16 
Ceramic Joining and Integration 
-Joining with Eutectic Phase Tapes: Microstructure 
• 
M313: Parallel SA-THX /1 layer Si-Hf Eutectic tape I Parallel 
SA-THX. Magnifications of x250 and x500 (top) and magnification 
at x1 000 (w/EDS results) (bottom). 
Brazing with the eutectic phase tape 
does not require a load and complex 
shapes can be joined. 
Joining of SA-Tyrannohex in 
the parallel orientation. 
Spot c Si AI Hf 
1 63.12 36.88 
2 64.30 35.70 
3 67.75 32.25 
4 63.82 35.40 0.78 
5 55.93 44.07 
6 56.83 43.17 
7 55.28 44.72 
8 32.89 67.11 
Sa 100.00 
9 32.92 67.08 
9a 100.00 
10 32.34 67.66 
lOa 100.00 
17 
Ceramic Joining and Integration 
-Joining with Eutectic Phase Tapes: Microstructure 
• 
M314: Perpendicular SA-THX /1 layer Si-Hf Eutectic tape I 
Perpendicular SA-THX. Magnifications of x250 and x500 (top) 
and magnification at x1 000 (w/EDS results) (bottom). 
Joining of SA-Tyrannohex in 
the perpendicular orientation. 
Spot c Si Hf 
1 61.71 38.29 
2 61.81 38.19 
3 57.41 42.59 
4 57.63 42.37 
5 53.25 46.75 
6 65.12 34.88 
7 100.00 
7a 31.28 68.72 
8 100.00 
Sa 32.32 67.68 
18 
Ceramic Joining and Integration 
-Joining with Eutectic Phase Tapes: Microstructure 
M317: Ml SiC/SiC I 2 layers Si-Hf Eutectic tape I Ml SiC/SiC. 
Magnifications of x250 (top) and x400 (w/EDS results) (bottom). 
,.. 
,.. 
Joining of melt-
infiltration SiC/SiC. 
Spot c Si 
1 72.62 27.38 
2 72.11 27.89 
3 68.34 31.66 
4 68.89 31.11 
5 66.51 33.49 
6 56.57 43.43 
7 78.06 
8 73.46 
9 72.41 
10 72.04 
11 100.00 
11a 49.96 50.04 
12 49.74 50.26 
13 49.76 50.24 
14 48.90 51.10 
• 
Hf 
21.94 
26.54 
27.59 
27.96 
19 
Ceramic Joining and Integration • 
-Joining with Eutectic Phase Tapes: Mechanical Tests · · 
cu 
a. 
::!! 
-'= 
.... 
C) 
c 
C1) 
.... 
.... 
UJ 
.... 
cu 
C1) 
-'= UJ 
.... 
c 
~ 
cu 
c.. 
c.. 
<C 
Load 
Samp • .....___.."71---J 
40 
35 
30 
25 
20 
15 
10 
5 
0 
0 
Test configuration for single 
lap offset shear test. 
I 
• ... • • 
... 
... 
... 
• Parallel Tyrannohex with 1 layer Si-Hf 
• Parallel Tyrannohex with 2 layers Si-Hf 
200 400 600 800 1000 1200 
Temperature, oc 
Strengths of parallel Tyrannohex joints. 
140 
cu 
a. 120 ::!! 
-'= .... 100 C) 
c 
~ 80 .... 
UJ 
.... 
cu 60 C1) 
-'= UJ 40 .... 
c 
~ 
cu 20 
c.. 
c.. 0 <C 
I 
t 
e Perpendicular Tyrannohex with llayer Si-Hf 
• Perpendicular Tyrannohex with 2 layers Si-Hf 
0 200 400 600 800 1000 1200 
Temperature, oc 
Strengths of perpendicular 
Tyrannohex joints. 
20 
Sub-Element Testing and Characterization 
• 
Objective: model and conduct judicious selection of materials; test materials, coated materials, 
airfoils, and joined sub-elements to evaluate capabilities in more relevant conditions. 
<IS 
a. 
2 
.r: 
-C) c: 
Cl) 
.... 
-Cl) 
Cl) 
.... 
:I 
-Q. 
:I 
0:: 
(.) 
en 
-0 
en 
=r I • Hi-Nicalon -e--+- • Tyranno SA ---- _ 50 • Sylramic-iBN =+-
• Hi-N icalon-S 0 ~ 300 
• Super Sylramic-iBN (developmental) C') 
• est from single fiber data - 40 
-(/) 
250 -+-- ... 0 
:::0 
c: 
- 30 200 --! c 
-
150 ~ c: .., CD (/) 
- 20 
-
.., 
CD 
:I 
.® r-+ cc 
-
- 10 ~:I" 
50 
100 hr 100 hr 100 hr 12(){)0C 1400"C 16(){)0C 
0 
' 
~ I t j t 30 32 34 36 3B 42 44 46 
Larson-Mililer Parameter: q = T (log t + 22) x 10-3, (Kelvin, hours) 
Effects on SiC/SiC Rupture Strength Data in Air by 
Reinforcement of a CVI-MI Matrix with various High-
Performance SiC Fiber Types. 
" !!. 
300 
nl 
Q. 250 
:!! 
.£ 
-CJ zoo c: 
~ 
.... 
-
(/) 
~ lSO 
.... 
:J 
-c. 
:J 100 0:: 
0 
en 
-
50 0 
en 
0 
\ 
\ 
' \ • CVI-MI Matrix : Vt0 - 18% 
' • Full CVI Matrix: Vt0 -18% • - 40 \ \ \ \ • Full PIP Matrix: Vt0 - 25% 
• ' • Full PIP Matrix: modeled for \ 
\ 
\ Vt0 - 25% Super Syl-iBN fiber ---· 
' 
..I 30 
. 
\ 
\ 
' \ 
' 
' 
..! 20 \ 
' 
' ~ 
~ 
- 10 
100 hr 100 hr 12000C 16000C 
t t 
32 33 34 35 36 37 38 39 41 42 43 44 45 46 47 48 49 
Larson-Miller Parameter: q = T (log t + 22) x 1 Q-3 
Rupture Strength in Air for SiC/SiC CMC with CVI-
MI, Full-PIP, and Fuii-CVI Matrices reinforced by 
Sylramic-iBN Fibers. Also Tyrannohex SA(--). 
An empirical model will be developed to act as the foundation of a more physics-based 
mechanistic model and predictive tool for down-selection of the optimum SiC/SiC 
processes, materials, and microstructures for a CMC HPT vane. 
21 
so. 
0 
-so. 
0 
~ 
c: 
"C 
-c: 
~ 
CD 
en 
-
.., 
CD 
:I 
:a 
-~:::J" 
" !!!. 
Sub-Element Testing and Characterization 
• 
- Laser High Heat Flux Thermal Gradient Tests 
Laser High Heat Flux Thermal Gradient Rig 
The rig allows for thermal cyclic tests, steam tests, bi-axial creep 
tests, and durability tests of coatings and materials. 
Two cooling air heaters, both are capable of providing up to 
815° C (1500F) temperature cooling air, were designed for airfoil 
foam-core hole cooling air supplies and also for general backside 
cooling requirements. 
Testing of the CMC/foam hybrid in air, 
using 1 hr cycles, to complete total 50 
hrs testing. 22 
Sub-Element Testing and Characterization 
-High Velocity High Pressure Burner Rig: Material Recession 
High Velocity High Pressure 
Burner Rig Recession Tests 
6 -16 atm and 200m/s gas velocity 
Recession rates of Tyraonnohex SA SiC composite 
as compared to other ceramic materials. Unlabeld 
test conditions are standard condition, 6 atm 30 m/s. 
Temperature, oc 
1600 1500 1400 1300 1200 1100 1000 10 ~--~~----~--~--~------~----~~ 
SiC/SiC under high :locit\ 
[;i Tyranohex SA (16 atm, 30m/s) 
0.0005 0.00055 0.0006 0.00065 0.0007 0.00075 0.0008 
liT K- 1 
' 
-- BSAS baseline 
EE SiC/SIC CMC 
0 ASSOO 
0 SN282 
• BSAS 
~ La2Hf207 
• Hf02 (doped) 
e HfRE Aluminosilicate 
D Yb-Silicate 
[;i SiC/SiC CMC (200 m/s) 
• Tyranohex SA SiC composite (200m/s) 
--- -[SJ---- BSAS (200m/s) 
- -0- - Hf02-t (200 m/s) 
--- - - --- - Goal 
- -6 - Tyranohex SA SiC composite (6 atm, 200m/s) 
- - -t:s:- Tyranohex SA SiC composite (16atm, 200m/s) 
23 
Model Development of Relevant Stresses in 
the Component 
Objective: Investigate design issues for a vane component with emphasis on thermal and 
mechanical conditionals, material capabilities, and component cooling. 
Approach: - In-house: stress analysis on first generation airfoils 
- Out-of-house: N&R Engineering Phase 1 and Phase 2 SBIRs. 
NOV 10 2009 
07 , 19 , 06 
-101079 -10822 34307 79436 
-78515 -33386 11743 56871 102000 
38 blade turbine d1sk at 44000 rpm with Si3N4 blades 
Blade Stress Analysis for Determination 
of a Blade versus Vane Task. 
2151 2 1 9 1 2211 
2111 2211 2251 2271 
Vane Temperature 
Distribution (N&R). 
2Jl l 
ZJJl 
Vane Pressure Loads (N&R). 
24 
Model Development of Relevant Stresses in the Component 
-Thermal and Stress Analysis of Vane Designs 
Airfoil Concept #1 
- Internally Cooled Vane 
JUN 30 2011 
14 : 30 : 09 
RWP>ranPt.r>:'\t 
220 222 . 188 224 . 375 226.562 228 . 75 
221.094 223.261 225 . 469 227 . G56 230 
SiC/SiC composi-:e HPT vane with cooling holes for T700 engine - units inches 
Airfoil Concept #2 
- Film Cooled Vane 
• 
0 
• 
0 
• 
0 
• 
0 
• 
For the above designs, thermal profiles and loads due to 
thermal and mechanical stresses will be calculated. 
• 
25 
Summary/Conclusions 
• 
• CMCs in turbine engine applications offer such benefits as: 
- Reduced fuel burn, reduced emissions, and lower weight 
- Higher temperature capability enables engine operation at higher power density 
(higher temperature and pressure) 
- Reduced cooling results in improved efficiency 
• The SRW Airfoil task is addressing unique challenges the for the LCTR mission 
and engine class. 
• Progress is being made in critical areas to include: 
• Small component fabrication 
• Ceramic joining and integration 
• Material and component testing and characterization 
• Design and analysis of concept components 
• The concept sub-components and components with features for study will be 
demonstrated in challenging conditions that are relevant to the engine conditions. 
26 



Ceramic Matrix Composites for Rotorcraft Engines

 Ceramic Matrix Composites for Rotorcraft Engines  
Ceramic matrix composite (CMC) components are being developed for turbine engine 
applications. Compared to metallic components, the CMC components offer benefits of 
higher temperature capability and less cooling requirements which correlates to improved 
efficiency and reduced emissions. This presentation discusses a technology develop effort 
for overcoming challenges in fabricating a CMC vane for the high pressure turbine. The 
areas of technology development include small component fabrication, ceramic joining and 
integration, material and component testing and characterization, and design and analysis 
of concept components.  
 
https://ntrs.nasa.gov/search.jsp?R=20110011258 2019-08-30T15:24:58+00:00Z
1National Aeronautics and Space Administration
www.nasa.gov
Fundamental Aeronautics Program
Michael C. Halbig
Task Lead, Materials Research Engineer
Ceramics Branch, NASA Glenn Research Center
Subsonic Rotary Wing Project
Ceramic Matrix Composites for Rotorcraft Engines
2011 Technical Conference
March 15-17, 2011
Cleveland, OH
2Acknowledgements
• Thank you to the Subsonic Rotary Wing Project and the Fundamental 
Aeronautics Program for their support.
• The team for the CMC Vane task includes:
– Ram Bhatt, Army Research Laboratory, Cleveland, OH
– Jay Singh, Ohio Aerospace Institute, Cleveland, OH
– Craig Smith, Ohio Aerospace Institute, Cleveland, OH
– Narottam Bansal, NASA Glenn Research Center, Cleveland, OH
– Jim DiCarlo, NASA Glenn Research Center, Cleveland, OH
– Martha Jaskowiak, NASA Glenn Research Center, Cleveland, OH
– Jerry Lang, NASA Glenn Research Center, Cleveland, OH
– Sai Raj, NASA Glenn Research Center, Cleveland, OH
– Dongming Zhu, NASA Glenn Research Center, Cleveland, OH
– Mike Halbig, NASA Glenn Research Center, Cleveland, OH
3Outline
• Background Information on Ceramic Matrix Composites
– Applications
– Processing and properties
• Turbine Vane Application for Rotorcraft Engines
• Key Technology Development for Turbine Vanes in the SRW Project
– Small component fabrication
– Ceramic joining and integration
– Material and component testing and characterization
– Design and analysis of concept components
• Summary/Conclusions
4Applications for CMCs in Gas Turbine Engines
Benefits:
• Enabling for high OPR engines (higher turbine inlet temperatures) –
reduce cooling air, reduce fuel burn and CO2 emissions
• Weight = 1/3 of metals and 1/2 of titanium aluminides
• High OPR engines – higher combustor temperature – increased NOX,
CMC combustor liner and first stage turbine vane reduce NOX
Courtesy of GE Aircraft Engines
5Fabrication Process for Gen III SiC/SiC CMCs 
(2700º F Capability for G.T. Engines)
preform
PIP CMC or 
CVI + PIP 
CMC
6Ceramic Matrix Composite Materials
- Melt Infiltrated (MI) SiC/SiC
SiC grains and silicon within MI matrix 
90° SiC fiber tow
CVI SiC
100µm
MI matrix
0° SiC fiber tow
0-90 Plain Fiber 
Tow Weave
Composite 
Cross-Section
• High thermal conductivity matrix
• Elimination of interlaminar porosity
• No matrix micro cracking
10 µm
BN Interphase
SylramicTM SiC fibers within a tow 
SiC Fiber
7Commercial High Temperature Ceramic Material
- SA-Tyrannohex (SiC Fiber Material)
Optical Micrograph SEM Micrograph
Features
• 8 Harness Satin Weave of SiC
Tyranno fibers
• Layers hot pressed together
• Hexagonal sintered fibers
• Nano-layer of carbon on the 
fiber surface
Benefits of SiC SA-Tyrannohex
• High fracture toughness
• Fatigue resistance
• Low weight and high temperature capability
• Machinable and complex shape formation
• Candidate material for the vane endcap
8 Harness Satin 
Fiber Tow Weave
8SRW Large Civil Tilt Rotor Mission and Requirements
LCTR Mission: 90 passengers, range: 1000 nmi., cruise speed 300 knots, cruise alt.: 28 k-ft.
LCTR Engine Characteristics:
7500-8000 HP, overall pressure ratio of 30, T4: 3000ºF hover and 2500ºF cruise, HPT turbine 
vane will have dimension of about 1” high and 1” long.
Engine T4 (º F) Overall Pressure Ratio
V22 (AE1107) 1740 16.7
T700 2600 17
LCTR2 (notional engine) 3000+ 30+
Comparison between the LCTR2 engine and other engines.
EIS = 2025 (2018 tech)
TOGW =108k lbm
Payload = 90 pass.
Engine = 4x7500HP
Fuel = 21,000 lbm
Range > 1,000nmi
Cruise > 300 knots
@Alt. ⇒ best range
Cruise L/D ≈ 12
Rotor tip speed
650 fps hover
350 fps cruise
9SRW Vane Task Overview
Objective:
 Develop technologies for CMC turbine engine components that have higher temperature capability, 
higher fracture toughness, and require less cooling compared to current metallic turbine components.
 Targeted toward the first stage vane of the high pressure turbine (HPT).
 Provides higher efficiency, higher horsepower, and lower emissions.
 This is a technology development task rather than a component task
NASA GRC role vs. industry role: 
NASA GRC is focused on a cooled HPT (lower TRL) whereas industry may be more focused on less 
cooled and lower temperature components (higher TRL) in the low pressure turbine (LPT). 
GRC is focused on the engine requirements of the Large Civil Tilt Rotor Vehicle within the Subsonic 
Rotary Wing Project.
SRW’s CMC effort compared to CMC efforts in other NASA projects (FA and ERA): 
The SRW task is focused on small component fabrication and joining technology development. 
All CMC tasks within the projects communicate well with one another to ensure tasks are leveraged  
and there are no overlap in efforts.
Challenges: 
Fabrication of a small airfoil (1”x1”), cooling schemes, engine operating conditions (i.e. T4 > 3000F, and 
OPR > 30), and joining to fabricate the component.
10
Current Metallic Vane Designs and Cooling Schemes
The preference in CMC 
turbine component 
development is to insert the 
CMC part in-place of the 
metallic one(s) rather than to 
drastically alter the outer 
geometry. 
11
Challenges with CMC Vanes and Airfoils
• Production challenges are in fabricating the small radii, the tapered trailing edge, integrating the 
endcaps, and machining cooling holes.
• Design and material challenges are in meeting the high stress and high temperature 
requirements, providing sufficient cooling, and having a durable high temperature coating.
Tapered wall 
thickness at trailing 
edge
Cooling
holes
Endcap joining
Endcap joining
Hot combustion gas
High stress and 
temperature
High stress
High
temperature
Cooling channel
12
Areas Being Addressed by the SRW Vane Task
Key Technology Development for a Turbine Vane in 
the SRW Project
– Small component fabrication
– Ceramic joining and integration
– Material and component testing and 
characterization
– Design and analysis of concept components
13
Small Component Fabrication 
- Objective and Concept #1
Objective: Demonstrate fabrication ability of small 1”x1” airfoils (vane cord length x height)
Materials: SiC/SiC (w/Sylramic and Hi-Nicalon SiC fibers) in the form of braided CMCs, 
CMC/ceramic foam hybrid, SA-Tyrannohex hot pressed and machined into an airfoil shape
Issues: inter-laminar strength, leading edge, trailing edge, cooling channels, surface cooling holes
Based on T-700 metallic vane contour 
and possible cooling hole choices.
Two types of silicon carbide fiber will be 
used for fabrication (Sylramic and Hi-
Nicalon-S).
The airfoils should be delivered by April.
The 6” length will be cut down and allow 
for multiple tests and characterization.
Planned Sub-Element Testing
- Burner rig testing with and without internal 
cooling and EBC
- Heat flux test with and without internal 
cooling and EBC
- Testing of joined elements
CMC plug 
w/unidirectional
fibers
Inner CMC tube 
Ceramic foam (SiC) 
w/ cooling channels
Cooling cavity
Outer CMC tube 
Airfoil Concept #1 
- Internally Cooled Vane
Endcaps will be 
joined to each end of 
the 1” long airfoil
14
Small Component Fabrication
- Concept #2
Airfoil
Endcap/Ring 
Section
Endcap/Ring 
Section
Airfoil Concept #2 
- Film Cooled Vane
The likely materials will be:
- SiC/SiC for the airfoil
- SA-Tyrannohex for the endcap
The airfoil will be fabricated this 
summer.
Planned Sub-Element Testing
- Burner rig testing with and without internal 
cooling and EBC
- Heat flux test with and without internal 
cooling and EBC
- Testing of joined elements
15
Ceramic Joining and Integration
Objective: Develop ceramic to ceramic (and ceramic to metal joining technology)
Materials: SiC/SiC, SA-Tyrannohex, (and superalloys)
Approach: - Develop processing details:
- interlayer
- conditions: time, temperature, and duration
- method: diffusion bonding, brazing, etc.
- Start with ceramic to ceramic joining of simple shapes
- Join more complex shapes
- Characterize and test (i.e. microstructural analysis, mechanical tests, thermal 
cycling, and burner rig)
Joining of airfoil 
and endcaps
Sample
Load
Fixture
Test configuration for single 
lap offset shear test.
16
• Ceramic substrates were 
ultrasonically cleaned in Acetone 
for 10 minutes
• Substrates were sandwiched 
around braze and foil layers 
•
• Mounted in epoxy, polished, and 
joints characterized using optical 
microscopy and scanning electron 
microscopy with energy dispersion 
spectroscopy analysis
• Atmosphere: Vacuum
• Temperature: 1340ºC
(10ºC above the braze     
liquidus temperature)
• Load: 100 g/sample
• Duration: 10 minutes
• Cool down: 2 ºC/min
BrazingDiffusion Bonding
• Atmosphere: Vacuum
• Temperature: Ti 1200ºC,
Mo 1400ºC
• Pressure: 30MPa
• Duration: Ti 4 hr
B-Mo 4 hr
• Cool down: 2 ºC/min 
Applied Load
SiC
SiC
Joining 
Interlayer
Materials (dimensions 0.5” x 1”)
- Substrate: SiC/SiC and SA-
Tyrannohex
- Interlayers: Ti foil (10, 20 micron)
and B-Mo alloy foil (25 micron)
Materials (dimensions 0.5” x 
0.5”)
- Substrate: SiC/SiC and SA-
Tyrannohex
- Interlayer: pastes and tapes of 
Si-based eutectics
Ceramic Joining and Integration
- Joining Processes
17
Ceramic Joining and Integration - Diffusion Bonding 
with 10 µm Ti Foil and 25 µm B-Mo Alloy Foil
C Si Ti
1 54.28% 45.72% 0%
3 44.89% 15.79% 39.33%
5 0% 69.39% 30.61%
C Si B Mo O
1 58.34% 41.66% 0% 0% 0%
3 19.09% 5.51% 63.96% 8.25% 3.19%
5 0% 0% 89.18% 10.82% 0%
Percents are atomic % Percents are atomic %
SA-Tyrannohex / Ti / SA-Tyrannohex SA-Tyrannohex / B-Mo alloy / SA-Tyrannohex
Very good quality bonds are obtained that are uniform and crack free. 
However, the joining process requires high applied loads and flat sub-elements for joining.
Joint
SA-TX
SA-TX
Joint
SA-TX
SA-TX
18
Ceramic Joining and Integration 
- Joining with Si-based Eutectic Phase Paste
Parallel SA-Tyrannohex / Si-Hf Eutectic paste / Parallel SA-Tyrannohex
- Magnifications at x10, and x100
Joint
SA-TX
SA-TX
Joint Gap
SA-TX
SA-TX
• Joints from Si-Hf eutectic phase paste are good quality showing adhesion to the ceramic 
substrates and no microcracking or fiber delaminations.
• However, joint formation is not uniform across the length and gaps are observed. Similar 
results were also obtained with Si-Ti and Si-Cr eutectic paste.
• Processing with Si-Hf eutectic tape interlayers rather than with pastes is being pursued to 
provide more uniformity across the joint.
19
Joining with Eutectic Phase Tapes
• Three different substrates: SA-Tyrannohex
(parallel), SA-Tyrannohex (perpendicular), 
and MI SiC/SiC.
• Joining interlayer: Si-Hf Eutectic tape - 1 layer 
and 2 layers.
• 8-14 pairs were joined from each of the six 
sets.
• Joined with 2 mm offset for mechanical tests.
Ceramic Joining and Integration
- Joining with Si-Hf Eutectic Phase Tape
SA-TX parallel, 1 layer
SA-TX perpendicular, 2 layers
MI SiC/SiC, 2 layers
Preparation of SA-TX (‖) w/2 layers
Joint characterization will include optical microscopy and scanning electron 
microscopy (SEM) with EDS, and mechanical testing (single lap offset).
20
Material and Component Characterization and Testing 
Objective: model and conduct judicious selection of materials; test materials, coated materials, 
airfoils, and joined sub-elements to evaluate capabilities in more relevant conditions.
Effects on SiC/SiC Rupture Strength Data in Air by 
Reinforcement of a CVI-MI Matrix with various High-
Performance SiC Fiber Types.  
Rupture Strength in Air for SiC/SiC CMC with CVI-
MI, Full-PIP, and Full-CVI Matrices reinforced by 
Sylramic-iBN Fibers. Also Tyrannohex SA ( ).
An empirical model will be developed to act as the foundation of a more physics-based 
mechanistic model and predictive tool for down-selection of the optimum SiC/SiC
processes, materials, and microstructures for a CMC HPT vane. 
21
Material and Component Characterization and Testing
- Laser High Heat  Flux Thermal Gradient Tests
Laser High Heat  Flux Thermal Gradient Rig
reflectometer 10.6  micron 
laser  beam
cooling air
specimen
3. 5  KW CO2 High Power Laser
ceramic coating
Superalloy substrate
platinum flat coils
aluminum back plate
air gap
cooling air tube
TBC coated
back aluminum
plate edge
pyrometers
bond coat
camera
Material and Component  Characterization and Testing – Ceramic 
Specimen Tested Under Cyclic Heat Flux Thermal Gradients
SA Tyrannohex initially selected 
for SRW project baseline airfoil 
material for evaluation: 1” square 
plate specimen
Specimen under testing
0
200
400
600
800
1000
1200
1400
1600
0 50 100 150 200
Tsurface, °C
Tback, °C
Te
m
pe
ra
tu
re
, °
C
Time, hours
Reduced cooling
• SA Tyrannohex ceramic selected as a candidate material due to its excellent high temperature 
mechanical and thermal properties.
• The first 25x25x10 mm specimen was tested at under turbine thermal gradient cycling conditions: 
Tsurface 2300-2400ºF (1260-1316ºC), Tback 1700-1750ºF (927-954ºC), 1 hr cyclic in air, for total 
195 cycles
• Late stage testing (after ~110 cycles) showed specimen delamination (increased surface 
temperature and reduced back temperature with cycling under heat flux)
22
Material and Component  Characterization and Testing 
- High Temperature Biaxial Creep Tests
High temperature biaxial creep tests is 
an ideal testing capability for SRW 
coating and CMC airfoil development. 
Cooling 
shower head 
jets
specimen
Ball-on-Ring 
fixture
-0.15
-0.10
-0.05
0.00
0.05
0.10
0.15
-500
0
500
1000
1500
0 5 10 15 20 25
Creep displacement
Load, N
D
is
pl
ac
em
en
t, 
m
m
Lo
ad
, N
Time, hours
High temperature biaxial creep tests rig.
FEM analysis of a coated disk.
Creep response at 454 N constant loading 23
24
Material and Component Characterization and Testing
- High Velocity High Pressure Burner Rig 
High Velocity High Pressure Burner Rig 
Recession Tests
6 atm, tested at 2500ºF specimen surface, 200m/s 
gas velocity 
3x1/2” bar 
specimen set up
Uncoated SA Tyrannohex Ceramic 
Specimen High Pressure Burner Rig 
Recession Tests – 200 m/s
0.0
0.5
1.0
1.5
2.0
0 5 10 15 20
Specimen #7 weight loss, mg/cm2-h
Specimen #8 weight loss, mg/cm2-h
Sp
ec
im
en
 #
7 
w
ei
gh
t l
os
s, 
m
g/
cm
2-
h
Total accumulated time, hr
25
Design and Analysis of Concept Components
Objective: Investigate design issues for a vane component with emphasis on thermal and 
mechanical conditionals, material capabilities, and component cooling.
Approach: - In-house: stress analysis on first generation airfoils
- Out-of-house: N&R Engineering Phase 1 and Phase 2 SBIRs.
Blade Stress Analysis for Determination 
of a Blade versus Vane Task.
Vane Temperature 
Distribution (N&R).
Vane Pressure Loads (N&R).
26
Design and Analysis of Concept Components
- Thermal and Stress Analysis of Vane Designs
Airfoil Concept #1 
- Internally Cooled Vane
Airfoil Concept #2
- Film Cooled Vane
Additional Design for 
Internally Cooled Vane
For the above designs, thermal profiles and loads due to 
thermal and mechanical stresses will be calculated. 
27
Summary/Conclusions
• CMCs in turbine engine applications offer such benefits as:
- Reduced fuel burn, reduced emissions, and lower weight
- Higher temperature capability enables engine operation at higher power density 
(higher temperature and pressure)
- Reduced cooling results in improved efficiency
• The SRW Vane task is addressing unique challenges the for the LCTR mission 
and engine class.
• Progress is being made in critical areas to include:
• Small component fabrication
• Ceramic joining and integration
• Material and component testing and characterization
• Design and analysis of concept components
• The concept sub-components and components with features for study will be 
demonstrated in challenging conditions that are relevant to the engine conditions.
28Your Title Here


Ceramic Matrix Composites for Rotorcraft Engines

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