© Rolls-Royce plc 2011
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Titanium in Aero-Engines Developments and the Way Forward
Amit Chatterjee
Sr Mgr, Materials
Titanium 2011, Oct 2-Oct 5, 2011 San Diego, USA
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2
© Rolls-Royce plc 2011
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3 The Drive for Cost
History of air transport shows a
continuous reduction in real
price of travel whilst airline
margins are also falling
To meet airlines’ requirements
we must continuously raise our
standards of technology to
achieve improved performance
while driving cost down
It is critical that we reduce the
cost of materials and processes
since these underpin final
engine cost
Fares (1992 US cents per revenue
passenger kilometer)
1960 1965 1970 1975 1980 1985 1990
4
8
12
16
0
1970 1975 1980 1985 1990
4
0
-8
-4
Profit/loss (constant 1992 $b)
Source: DTI analysis of ICAO data
Titanium 2011, Oct 2-Oct 5, 2011 San Diego, USA © Rolls-Royce plc 2011
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Alloy Content
Nickel
40%
All Others
5%
Steel
25%
Titanium
30%
Materials in a current civil engine
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Materials
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6 Ti Disc alloy temperature capability
Temperature
Capability (C)
1960 1970 1980 1990 2000
350
600
α-β Alloys
High strength α-β Alloys
Near-α Alloys
Aerofoil ‘fire line’
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Titanium Disk Alloy Development
Alloy development for increased strength
& temperature capability
Ti6-4 Workhorse alloy up to 300°C
Ti6246 High strength alloy up to 450°C
Ti6242 Near alpha alloy up to 525°C
IMI 834 Optimised creep & fatigue strength alloy up to 600°C
Ti6-4 Ti6246 IMI 834
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8 Titanium in Discs – R-R 3 shaft history
Increasing temperature
Decreasing space
= Increased Ni alloy use
1980 1990 2000 2010
HP
IP
Ti685 Ti829 Ti834
Fan
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Higher temperatures - Aluminides
Ti Aluminides for lower density & greater temperature capability
Cast and wrought technology development underway
Cast 45-2-2XDTM early medium strength alloy
High strength & temperature capable wrought alloys e.g. TNB
Cast 45-2-2XDTM Wrought TNB
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Focussed on near net shape technologies Casting process development
optimise mould filling
avoid costly machining operations (eg aerofoil)
Design studies Optimise root fixing and aerofoil geometries
Limit peak mechanical stress
Material behaviour and validation Understanding alloy / process / structure / property
relationships
Material, component and engine testing
Supply chain development Partnerships with capable suppliers
Cost reduction opportunities
Titanium Aluminides ( Gamma )
Large civil LPT blade
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Weight Reduction - TiMMC & IMC
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TiMMC Blings
Conventional
disk & blades
Blisk - up to 30% weight
saving Bling - Ti MMC - up to
70% weight saving
EJ200 size TiMMC reinforced Bling
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Where next…
New aluminide compositions &
heat treatments
Improved properties at low cost
Aluminide Composites
Orthorhombic matrix with
high strength SiC fibers
Strengths >2000MPa at 650°C
Rotor concepts demonstrated
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Clappered
1950’s
Solid
Hollow Wide-chord fan
1st generation
Honeycomb
Higher efficiency
Lower noise
High damage resistance
1970’s
Leading Ti hollow Wide Chord Fan Technology
DBSPF* ‘girder’
Low weight
2nd generation
1990’s
Low noise
Low weight
High efficiency
High flow
DBSPF* ‘girder’
Swept
3rd generation
2000+
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15 The challenge from composites
Fan case
OGV
Filament-
wound spinner
Fan case liners
By-pass ducts
Fan Blade
Fan
Containment
case
PMC Fan Blade
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Other Competing Material Systems
1. PROGRESS & PROMISE IN DISCONTINUOUSLY REINFORCED ALUMINUM
Benji Maruyama1, Daniel B. Miracle, 1 Air Force Research Laboratory, Materials & Manufacturing Directorate, WPAFB, OH 45433
2. http://www.gknaerospace.com/Office/Content/S634147899815309415/Composite-Technology-Briefing-Farnborough-2010.pdf
Fan exit Guide Vane – PW 4084
Stylized High Temperature Composite
Vane – 325C 2. GKN Publication Stylized High Temperature Composite
Vane – 325C
FMW Link – Ti with B additions
20 % increase in strength and stiffness
Titanium 2011, Oct 2-Oct 5, 2011 San Diego, USA
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Processes
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Ti Blisks
Weight
Performance
Design
Blisk Disk and blade set
© Lockheed Martin Corporation
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Blisks - Repair Instead of Replace
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Ti - Linear Friction Welding
Cost
Integrity
Flexibility
Optimised materials - hollow blades
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Ti - Linear Friction Welding
Cost
Integrity
Flexibility
Optimised materials - hollow blades
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Ti64-Metal Injection Molding
Typical Structures Green vs Sintered (Non
Aerospace Parts)
Mechanical properties exceeds ASTM F1472 requirements
Titanium 2011, Oct 2-Oct 5, 2011 San Diego, USA
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Ti64-Metal Injection Molding
Typical Structures Green vs Sintered (Non
Aerospace Parts)
Mechanical properties exceeds ASTM F1472 requirements
Titanium 2011, Oct 2-Oct 5, 2011 San Diego, USA © Rolls-Royce plc 2011
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Critical to Net-Shape
Predict Tool Cavity
Net-Shape Powder HIP
Model Tool Powder Fill Cavity HIP & Extract
Mild Steel Tooling
Powder Fill Can
- Evacuate, Vibrate, Heat
Seal
Hot Isostatic Press
Remove Can
- Machine then Pickle
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Finished Machined Ti64 Compressor Casing
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30 um
30 um
75 % reduction in machining time
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26 Material life cycle...
Design Make Certify + support in service
new alloys
new processes
new operating regimes
lifing
etc
manufacturing
change control
concessions
etc
underpins part life but
surprises in store:
WRT operation
WRT material behaviour
Driven by product requirements
Empirical iterative process
Mechanistic understanding
Demonstration of equivalence
Feedback loop – may take decades
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27 Need fundamental understanding
Physically based behavioural models
Improved right first time design
Accurate component life / durability prediction
Reduced life cycle cost and improved reliability
Physically based process / structure / texture
models
Optimised process routes for; Yield
Material properties
Rapid and accurate assessment of; Manufacturing change
Non conformance
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Cogging Forging Quenching
Heat treatment
& Ageing
Machining
Joining
Design
Requirements
Surface Treatment Material Properties & Lifing
Materials & Process Modeling: Forging
Alloy
Design
28
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29 Conclusions
Business drivers
product reliability
(life cycle) cost reduction Main developments – next 5-10 years
process / property / behaviour relationships – significant developments expected
Improvements in material & process modeling and component lifing methods
limited ‘new’ alloys for niche applications
increased application of near net shape technology, better buy/fly ratios
(Low cost) powder production and manufacturing for low risk Ti systems and repair technologies
Titanium 2011, Oct 2-Oct 5, 2011 San Diego, USA © Rolls-Royce plc 2011