Titanium Contact Mechanics
 Increasing use of titanium led to the need to specifically
investigate wear mechanisms, establish test methods and
provide solutions.
 Basic wear mechanism simulated by simple hammer wear
test and like versus like solutions introduced in the 1960’s
onwards which offered low wear with intermediate friction.
 Continued developments to introduce low friction
coatings appropriate to fan blade root fixings in the
1980’s.
 With the increased complexity of modern designs,
dedicated rigs are used to understand geometry and
service loadings.
IMFAIR Conference 10-11th June 2009
The Future of Design for Surface Engineering in Aerospace Applications
Fan Blade Low Friction Coatings
Friction Coe ffice nt v Cy cle s From Ox ford Biax ial Dov e tail Rig Te sting
0.7
Uncoated
A verage C oefficient of Friction
0.6
P L237 Only
0.5
0.4
0.3
M etco + P L237
0.2
0.1
0
1000
2000
3000
4000
5000
Cycles
IMFAIR Conference 10-11th June 2009
The Future of Design for Surface Engineering in Aerospace Applications
6000
7000
8000
9000
Fan Blade Low Friction
Coatings
Q
H
P
Q
Button on Plate Rig
Bi-axial Rig
Q
P
H
 Low loads, sliding
conditions
 Point contact
 Unrepresentative of
engine conditions
 Ranking test
Combined HCF/LCF cycles
 Representative of engine conditions (Load,
frequency etc)
 Fretting wear
 Representative edge of bedding contact
pressures / stresses
 Representative friction conditions
IMFAIR Conference 10-11th June 2009
The Future of Design for Surface Engineering in Aerospace Applications
Q
Advanced Sub-Element Testing

Fan Blade sub-element test:
captures geometry, surface
condition and loading.

Computer control:
combined load spectra as
in engine

Typical blade + Disc FE sector model
Low friction coatings give low
transmitted load
IMFAIR Conference 10-11th June 2009
The Future of Design for Surface Engineering in Aerospace Applications
Composite Plating Disc Fin Seal Coatings
 Abrasive coatings used to
control the degree of
frictional heating during
contact on disc fin seals.
 Works by cutting a clean
path in the abradable liner.
 Rig testing showed that the
application of the abrasive
system significantly reduced
the degree of heat
generated during rubs
IMFAIR Conference 10-11th June 2009
The Future of Design for Surface Engineering in Aerospace Applications
Highly Instrumented Abradability Facility
Alstom Abradability Facility
Room Temperature Abradability Facility
Located Rapperswil, Switzerland
Comparison of un-tipped with c-BN tipped nickel fins
Capable of Blade and Fin Assessment
Curved or Flat Test Piece Shoes
IMFAIR Conference 10-11th June 2009
The Future of Design for Surface Engineering in Aerospace Applications
Increases in TET associated with progress in
turbine materials and technology
Uncooled
Blades
Turbine Entry Temperature (K)
2100
Coated
Blades
Cooled
Blades
1900
Demonstrator
Technology
Production
Technology
Trent
1700
Thermal Barrier
Coatings
1500
Conway
RB211
SX cast
Spey
1300
W1
Dart
Avon
DS cast
1100
Cast Alloys
900
Wrought Alloys
1940
1960
1980
Year of introduction
IMFAIR Conference 10-11th June 2009
The Future of Design for Surface Engineering in Aerospace Applications
2000
2020
Turbine Blade – Cooling and Coating Technology
Gas Temp: 825ºC
Uncooled
Gas Temp: 1425ºC
Multipass
IMFAIR Conference 10-11th June 2009
The Future of Design for Surface Engineering in Aerospace Applications
Gas Temp: >1550ºC
Thermal Barrier
Coating
Alloying Additions into Turbine Blade Alloys
Source: R C Reed, Superalloys: Fundamentals and Applications, Cambridge University Press, 2005
IMFAIR Conference 10-11th June 2009
The Future of Design for Surface Engineering in Aerospace Applications
TBC Bondcoat Design
 Ability to establish a pure alumina
scale which exhibits a low growth
rate
 Improved phase stability to reduce
the influence of damaging substrate
elements
 Bondcoat capable of replenishing
the aluminium that is lost to alumina
formation
 Bondcoat compatible with single
crystal alloys and low parasitic
weight
 No impact on the thermal
mechanical fatigue properties of the
TBC system
 Strength at high temperature to
limit creep deformation
 No formation of SRZ’s on third and
fourth generation alloys
IMFAIR Conference 10-11th June 2009
The Future of Design for Surface Engineering in Aerospace Applications
Potential for a System Design Optimisation
Approach for Turbine Hardware
temperature capability
relative life at 1150°C
Temperature Capability °C
1300
x25
1250
x20
1200
x15
1150
x10
1100
x5
1050
1000
Base on CMSX- 4 alloy
Alloy optimisation
IMFAIR Conference 10-11th June 2009
The Future of Design for Surface Engineering in Aerospace Applications
Optimised on CMSX-4
Modelling
Define the material and
process
Requirements
Calculate process
parameters and
microstructure
Materials Data
Knowledge Base Computer System
Phase diagram model
Property models
Microstructural models
Process model
Cost model
Design Tools
Improve and
optimise
Solution
IMFAIR Conference 10-11th June 2009
The Future of Design for Surface Engineering in Aerospace Applications
Calculate mechanical
properties
Manipulating Atoms to Make Materials
Governments, corporations, and
venture capitalists spent more
than $8.6 billion worldwide on
nanotechnology R&D in 2004.
Nanograined
alloys
Nanoreinforced
polymers
Smart
Materials
Structural
materials
-
Nano
Materials
The United States has
appropriated over $4
billion for nanotechnology
R&D since 2000
Coatings
Anticoking
Low surface
energy
Tribology
Thermal
Low
friction
Anticorrosion
TBC
Fire
Retardant
IMFAIR Conference 10-11th June 2009
The Future of Design for Surface Engineering in Aerospace Applications
Hard
coatings
Titanium metal matrix composites
EJ200 size TiMMC reinforced Bling
Conventional
disk & blades
Blisk - up to 30% weight
saving
IMFAIR Conference 10-11th June 2009
The Future of Design for Surface Engineering in Aerospace Applications
Bling - Ti MMC - up to
70% weight saving
Systems Design - Making the Difference
Summary
 Requirement for “highly engineered” solutions
 Effective integration of materials and manufacturing
technology.
 Continuity of funding/teams
 Taking time out of the material development process
 Extensive use of modelling/simulation to expedite
material and process development
 Demonstrator opportunities
 Maintenance of key relationships with University network
and throughput of skills
IMFAIR Conference 10-11th June 2009
The Future of Design for Surface Engineering in Aerospace Applications
Reactive Design
Today
From
Predictive Design
To
 Evolving design requirements
 Defined design requirements
 Extensive development trials
 Controlled parameters
 Product performance assessed
by ‘ build and test’
 Product performance
modelled and simulated
 Empirical understanding
 Data driven environment
 Performance and producibility
problems fixed after product in use
 Designed for robust
performance and producibility
 Quality ‘tested in’
 Quality ‘designed in’
IMFAIR Conference 10-11th June 2009
The Future of Design for Surface Engineering in Aerospace Applications