Titanium Trends and Usage in Commercial Gas Turbine Engines

Jim Hansen – Materials & Processes Engineering

Jack Schirra – Advanced Programs

David Furrer, Ph.D. – Materials & Processes Engineering

2-5 October 2011

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What is the Future of Aerospace Titanium?

2

• Fuel represents ~50% Of airline costs

• Engines provide significant opportunity for fuel burn reduction

• Composite airframes also contribute to performance improvements

• Improved efficiency objectives are driving cycle and

architecture requirements challenging Ti engine usage

• Airframe applications driven by composite compatibility

promoting Ti usage

Ti research focus – affordability then performance

…is it the right balance?

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Outline

Historic Titanium Usage

Trends in Engine Architecture & Cycle

Impact to Material Usage

The Challenge - Material Requirements for

Next Generation Engines

3 This slide contains no technical data

Historic Titanium Usage

Alpha Case

(time dependent)

Ti Fire

(pressure dependent)

Adapted from ”Developments in High Temperature Titanium Alloys”

Blenkinsop, P.A. Titanium Science & Technology 1984

300

350

400

450

500

550

600

650

700

1940 1950 1960 1970 1980 1990 2000

Max

Te

mp

era

ture

-°C

Year of Introduction

Ti 6-4

Ti 17

Ti 6-2-4-2-S

IMI 834

Ti 6-2-4-2

IMI 829

IMI 550

Ti 8-1-1

IMI 679

IMI 685

Ti 48-2-2

Ti 6-2-4-6

PW Alloy C

Titanium historically limited by Alpha Case and compressor fire potential (& cost)

4 ECCN EAR99

Titanium Usage – Last Century

PW 4000 materials of construction • Titanium ~25% by weight

Fan Low

Pressure

Compressor

High

Pressure

Compressor

Ti

Fir

e

Lin

e

5

0

5

10

15

20

25

30

1950 1960 1970 1980 1990 2000 2010

Year

Perc

en

t o

f S

yste

m W

eig

ht

777

757 & 767

747

737

727707

J57

PW2037

PW4056

PW4084 PW6000

ECCN EAR99

Engine Efficiency Drivers

• Propulsive efficiency: Driven by increased bypass ratio

• Higher bypass ratio larger diameter fan

• To maximize benefits of a large fan:

• Need hollow titanium or composite fan blades

• Need light weight composite static structure

• Cycle efficiency: Driven by higher pressure ratio and

higher turbine inlet temperature

• Higher pressure ratios require higher temperature

capability in the high pressure compressor

• Higher turbine inlet temperatures require higher

temperature turbine materials and coatings.

Overall efficiency = Propulsive efficiency x Cycle efficiency

bypass airflow

bypass airflow

Fan

Conventional Turbofan

Compressor

Low High

Turbine

High Low

Bypass Ratio = Bypass Airflow / Core Airflow

6 ECCN EAR99

www.pw.utc.com

Bypass Ratio Drives Efficiency & Noise As bypass ratios increases

- Thrust Specific Fuel Consumption (TSFC) and noise decrease

Gas Turbine Technology Evolution: A Designer’s Perspective

Bernard L. Koff

TurboVision, Inc., Palm Beach Gardens, Florida 33418

JOURNAL OF PROPULSION AND POWER

Vol. 20, No. 4, July–August 2004

7

2006 Requirement

Stage 4 10dB

below Stage 3

EPNdb – Expected

Perceived Noise Level

ECCN EAR99

Whittle

Von Chain

J57J52

JT3D

J79

JT8D TF30

F100

F100CF6-50

JT9D-7R4

F404

2037

CF6-80

4056V25004060

41684084

GE90

Trent

0

5

10

15

20

25

30

35

40

45

1930 1940 1950 1960 1970 1980 1990 2000 2010

Co

mp

res

so

r P

res

su

re R

ati

o

Year

sea level static,

standard day

Compressor Temperature Trend

Increasing

Temperature

Gas Turbine Technology Evolution: A Designer’s Perspective

Bernard L. Koff

TurboVision, Inc., Palm Beach Gardens, Florida 33418

JOURNAL OF PROPULSION AND POWER

Vol. 20, No. 4, July–August 2004

Engine efficiency increases as compressor pressure ratios increase.

Compressor temperature increases with pressure.

“As the operating

temperature of turbine

engines increases,

titanium will struggle to

maintain its foothold in

aircraft high pressure

compressor disks.”

- G.Vroman, Sr. VP, ATI-

Ladish, from American

Metal Market,1998

8 ECCN EAR99

Engine Changes – Material Impacts

Engine architecture and cycles driving material changes away from titanium:

• Bypass Ratios Increasing = Larger Diameter Fans

• Organic matrix composites (OMCs) replacing Ti in fan blades and containment

cases

• Compressor pressure ratios increasing = Hotter compressors and turbines

• Transition to integrally bladed rotors results in material selected by gas path

requirements

• Nickel replacing titanium in earlier stages of the high pressure compressor

(HPC)

• High temperature turbines reduce stages where gamma alloys work

• Core diameters are decreasing

• The volume (size) of Ti & Ni components is decreasing

9

ECCN EAR99

Bypass Ratio & Fan Blade Materials

Materials play a key role in enabling higher bypass ratios by enabling larger

diameter light weight fans.

1960 - 1980s

Solid Ti

1990s

Hollow Ti

2000s

Composite

PW 1524G

BPR = 12

GE 90

BPR = 9 PW 4084

BPR = 6.4

JT3D

BPR = 1.3

2010s

Composite / Hybrid Metallic

10 ECCN EAR99

Bypass Ratio & Fan Case Materials

PW 4056

BPR = 4.8

Solid Steel

V2500

BPR = 4.5 - 5.4

Solid Titanium

Solid steel and titanium fan containment cases being replaced by Kevlar

composite and all composite designs to reduce weight.

GP7200

BPR = 8.8

Kevlar/Aluminum

PW1524G

BPR = 12

Composite

1980s

1990s

2000s

2010s

11 ECCN EAR99

Engine Changes

Fan Blades

Ti to Composite/Hybrid Metallic

(Ti leading edge sheaths)

SGV

Ti to Composite/Aluminum

HPC Rotors & Stators

Ti to Nickel

HPC Rotors & Stators

Gamma potential

Larg

er

Dia

mete

r F

an

s

Smaller Diameter,

Higher Pressure &

Hotter Cores

LPC Rotors & Stators

Ti to Composite/Aluminum

Engine architecture/cycle drives material changes

LPT Blades

Ni to Gamma Ti

12 ECCN EAR99

Titanium Usage – This Century

Commercial aircraft and engines

• Temperature limitations – Ceiling for utilization in engines

• New engines - Higher bypass ratios, smaller cores, increased

temperature / larger Fans reduced Ti content

13

0

5

10

15

20

25

30

1950 1960 1970 1980 1990 2000 2010 2020

Perc

en

t o

f S

yste

m W

eig

ht

Year

787

777

757 & 767

747

737

727707

J57

PW2037

PW4056

PW4084 PW6000

PW GTF

ECCN EAR99

Ti Development Challenges…From an Engine Perspective

Aluminum

OMC - BMI

Titanium

OMC - Polyimides

Gamma Ti

Nickel / Cobalt

Alpha Case

Burn Resistance

1100

1000

900

800

700

600

500

400

300

200

100

°C

Max use temperature

• Cost (always of great interest)

− Compete with Al & steel

• High specific capability (propulsive efficiency)

− Compete with composites

• Environmental resistance (thermal efficiency)

− Compete with superalloys

Structural Composite Materials, Chapter 1

F.C. Campbell, 2010, ASM International 14

$

ECCN EAR99

Airframe Technology Examples

Aluminum industry’s response to composites: increase performance

• High strength corrosion resistant alloys

• Increased strength & design compatible

• 3rd Generation Al-Li alloys

• Increased specific strength & stiffness

• Novel manufacturing methods (FSW)

• Hybrid materials (GLARE)

• GLARE® (GLAss fiber REinforced aluminum)

Similar advances/approach required for Titanium

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Next Generation Engine Opportunities

• Fan & LPC - Specific strength vs. OMCs

• Cost Effective MMCs, Ti + B (P/M), Hybrid Ti / OMCs

• HPC - Temperature capability and burn resistance

• Higher Temperature Capable & Burn Resistant Alloys and Coatings,

Expanded Use of Gamma Ti

• LPT - Creep and oxidation (Gamma Ti)

• Higher Temperature Capable Alloys / Coatings

• Low cost material and manufacturing processes

• Low Cost Raw Materials – Ti Reduction, Melting, Conversion

• Additive Manufacturing to Enable Hybrid & Low Cost Solutions

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Summary

• Titanium usage decreasing in engine applications

• Driven by cycle and architecture changes

• Displaced by organic matrix composites and super alloys

• Aluminum industry response to composite threat is increased

performance / advanced fabrication technologies

• Technology opportunities for Titanium

• Increased specific capability

• Advanced manufacturing for high performance structures

• Improved temperature capability systems (coatings)

• Continued work on cost reduction

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18 QUESTIONS ?

Thank You

0

5

10

15

20

25

30

1950 1960 1970 1980 1990 2000 2010 2020

Perc

en

t o

f S

yste

m W

eig

ht

Year

787

777

757 & 767

747

737

727707

J57

PW2037

PW4056

PW4084 PW6000

PW GTF

ECCN EAR99