Eric A. Ott

General Electric Aircraft Engines, Cincinnati, Ohio

Shape Changing Airfoil

NASA/CR—2005-213971

October 2005
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Eric A. Ott

General Electric Aircraft Engines, Cincinnati, Ohio

Shape Changing Airfoil

NASA/CR—2005-213971

October 2005

National Aeronautics and

Space Administration

Glenn Research Center

Prepared under Contract NAS3–01135, Work element 3.2, Task order 23
Available from

NASA Center for Aerospace Information

7121 Standard Drive

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National Technical Information Service

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Trade names or manufacturers’ names are used in this report for

identification only. This usage does not constitute an official

endorsement, either expressed or implied, by the National

Aeronautics and Space Administration.

Available electronically at http://gltrs.grc.nasa.gov
Contents 

I. Shape Change Airfoil Project Introduction ..............................................................................1 

A. Program and Project Background ......................................................................................1 

B. Project Objectives..............................................................................................................2 

C. Project Team and Plan .......................................................................................................2 

D. Deliverables .......................................................................................................................3 

II. Technical Summary of Aluminum Alloying Fundamentals Tasks ..........................................3 

A. Subtask 3.2.1: Nano Phase Aluminum Alloying Concepts ...............................................4 

Alloy and Alloying Technique Selection...........................................................................4 

Phase 1 Rapid Solidification Processing.........................................................................11 

B. Subtask 3.2.2: Nano Phase Aluminum Processing and Characterization ........................12 

Consolidation processing to produce bulk nano-phase aluminum materials..................13 

Al Alloy Characterization ................................................................................................15 

C. Subtask 3.2.3 Modeling ...................................................................................................18 

III. Technical Summary of the Shape Change Concepts Subtask ................................................19 

A. Component Level Concepts for Phase 1 Preliminary Down-Select ................................20 

B. Fan Airfoil Camber Change Concepts.............................................................................21 

Airfoil Geometry Change.................................................................................................21 

Actuation Concepts..........................................................................................................21 

C. Analysis of Aero Benefits................................................................................................27 

GE90 vs QAT ...................................................................................................................28 

Active vs Passive Actuation .............................................................................................28 

D. Structural Analysis...........................................................................................................29 

Mechanical Analysis........................................................................................................29 

Thermal Analysis .............................................................................................................32 

E. Refined Shape Change Airfoil Structure Concept ...........................................................32 

Titanium blade .................................................................................................................32 

Composite blade ..............................................................................................................34 

Aluminum blade ...............................................................................................................36 

F. Shape Change System Risk Assessment..........................................................................36 

G. Implications to the Engine System ..................................................................................38 

H. Summary..........................................................................................................................40 

IV. Conclusions and Recommendations.......................................................................................41 

A. Conclusions based on Phase 1 study................................................................................41 

B. Recommendations based on Phase 1 study......................................................................41 

V. Program Schedule...................................................................................................................42 

VI. References ..............................................................................................................................42 

NASA/CR—2005-213971 iii

I. Shape Change Airfoil Project Introduction 

A. Program and Project Background 

The National Aeronautics and Space Administrations (NASA) Ultra Efficient Engine 

Technology (UEET) efforts have recently included the Intelligent Propulsion System 

Foundation Technology (IPSFT) Program. As part of the IPSFT Phase I (2003-2004) 

program, the Shape Changing Airfoil Project was established to investigate the utilization

of intelligent control of airfoil shapes in order to reduce carbon dioxide emissions via 

reductions in engine fuel burn. Additional IPSFT project thrust areas in the Phase I effort 

included emissions, noise, and safety and reliability. Summaries of other projects focusing 

on these four major thrust areas, including a system study of the overall benefits of each of 

the IPSFT technologies are reported elsewhere. 

The shape changing airfoil system was considered to be at technology readiness level 

(TRL) 1 as of the initiation of this Phase I effort. As a result, the Phase I project plan was 

structured to assess shape change concepts and form a technology foundation that could 

then be further proven and developed during the later phases of the program. In parallel to 

efforts to establish an intelligent control technology, the initial phases of the effort also were 

structured to begin establishing fundamental materials technology for higher strength, 

intermediate temperature aluminum alloys which were envisioned to be candidates for a 

the backbone structure of a lightweight, affordable, shape changing airfoil system. The 

advanced aluminum material was intended to be a future base metal for the airfoil upon 

which the control system and related actuation materials and structures could be added. 

Performance of the shape change concept study and advanced aluminum alloy technology 

development efforts concurrently was intended to allow sufficient time for both technology

areas to reach TRL 6 by 2009. Fundamental material and process models were also being 

addressed in this project in order to accelerate the insertion of new materials technology. 

The GE Aircraft Engines engine system being considered as a baseline for assessment of 

the intelligent engine technologies is the 2015 Quiet Aircraft Technology (QAT). The QAT 

utilizes a commercial engine cycle with a number of advanced engine technologies studied 

under other GE Aircraft Engines contract efforts. 

This Shape Changing Airfoil project effort was designed around a General Electric (GE), 

NASA and Ohio State University (OSU) collaboration arrangement. Separate contracts 

were placed by NASA with GE and OSU, but efforts were performed in a collaborative 

fashion in order to best utilize the personnel, experience, analysis, and testing strengths of 

each of the collaborating organizations. The project areas covered in this final report relate 

specifically to the GE portion of the Shape Changing Airfoil effort; however, appropriate 

references to results achieved as part of the OSU investigation under this project focus 

area are included. Additional details can be found in the OSU final report to be published 

at the conclusion of the OSU Phase I efforts. The aluminum development efforts and the 

shape change concepts development portions of this project will be summarized in 

Sections II and III respectively. 

NASA/CR—2005-213971 1
B. Project Objectives 

The overall objective of this project was to develop materials and computational models to 

enable the design and fabrication of lightweight, high-strength shape-changing airfoils. 

The emissions improvement goal associated with this technology area was a 0.5% 

specific fuel consumption reduction. Such reductions would result in significant carbon 

dioxide emission reductions. Specific fuel consumption reductions were investigated 

through the study of shape change concepts in airfoil-type components and through 

development of lightweight airfoil materials fundamentals. 

C. Project Team and Plan 

Efforts performed in this project were organized into 4 separate subtasks. A summary of

the Phase I subtask objectives are given in Figure 1.3.1. Subtasks 1 through 3 were 

performed as a collaboration between GE Aircraft Engines, GE Global Research, Transmet 

Corporation, and Ohio State University, with NASA Glenn Research Center in an advisory 

role. Subtask 4 was performed as a collaboration between GE Aircraft Engines, and GE 

Global Research Center, again with NASA Glenn Research Center in an advisory role. A 

more detailed project plan and schedule can be found in Section VI. A summary of the core 

project team and team member affiliations is given in Table 1.3.1. Additional personnel 

were also consulted during this effort for guidance during various technical activities. 

Phase I Shape Changing Airfoil Project Structure 

Subtask 3.2.1: Nano Phase Aluminum Alloying Concepts 

• “Select most promising aluminum alloy compositions for evaluation as lightweight, highstrength shape changing materials.”

• “Manufacture lab-scale dispersion-strengthened aluminum alloys by rapid solidification 

techniques.”

Subtask 3.2.2: Nano Phase Aluminum Processing and Characterization 

• “Identify lab-scale manufacturing techniques for nano-phase aluminum materials.”

Subtask 3.2.3: Nano Phase Aluminum Modeling 

• “Nano Phase Aluminum Modeling”

Subtask 3.2.4: Shape Change Technology Scoping 

• “Perform aerodynamic analyses to determine blade shape change requirements and 

potential benefits.”

• “Assess shape changing materials technologies.”

Initial Phase 2 Shape Changing Airfoil Project Plans 

• Develop, produce and test lab-scale nano-phase aluminum materials using candidate 

manufacturing techniques selected in Phase 1. 

• Conduct manufacturing scale-up studies. 

• Develop and produce nano-phase aluminum for high-strength lightweight blades. 

Figure 1.3.1: Outline of the Shape Changing Airfoil Project Effort Phases I and II. 

NASA/CR—2005-213971 2
Table 1.3.1: Summary of Shape Changing Airfoil Project Team 

Organization Team members Relevant Tasks 

(3.2.x) 

GE Aircraft Engines Eric Ott (Lead) 1,2,3,4 

John Decker 4 

GE Global Research Center Shyh-Chin Huang 1,2,3 

Don Lipkin 4 

Matthew Lear 4 

NASA Glenn Research Robert Draper (Monitor) 1,2,3,4 

Ronald Noebe 1,2,3,4 

Ohio State University Michael Mills 1,2,3 

Glenn Daehn 1,2,3 

Mark Carroll 1,2,3 

Transmet Corporation Doug Shull 1,2,3 

Bruce Rademan 1,2,3 

D. Deliverables 

The project effort deliverables for Phase I are given below. The present report specifically 

addresses interim report requirements in the first 3 deliverables. For the fourth deliverable, 

material samples were produced and submitted to OSU for characterization as part of the 

project plan and as such this deliverable was also completed. 

1. Interim report on blade shape change requirements and benefits. 

2. Interim report on shape changing materials technologies, including most promising aluminum alloy 

compositions.

3. Interim report on lab-scale manufacturing techniques for nano-phase aluminum materials. 

4. Dispersion-strengthened aluminum alloy sample. 

II. Technical Summary of Aluminum Alloying Fundamentals Tasks 

Aluminum material development efforts included identification of approaches, production of 

materials, processing and characterization of alloys, and modeling of strengthening. These 

efforts were intended to provide a base of simple alloying concepts from which more 

complicated alloy compositions and microstructures may be developed in later phases of 

this effort. Tasks were performed by GE, Transmet Corporation (a subcontractor to GE), 

and OSU. Material identification, generation, and consolidation efforts were led by GE 

while characterization and modeling efforts were led by OSU. 

The overall alloying approach chosen in this study was based on the use of rapid 

solidification (RS) processing in order to develop high strength, highly stable alloys and 

microstructures. Many of the material structures which develop out of RS processing have 

microstructural features which are on the nanometer size scale and as such the alloys are 

also referred to as “nano” aluminum in this study. The use of RS processing and the 

resulting “nano” aluminum alloys was expected to provide the material strengthening 

NASA/CR—2005-213971 3
mechanisms whereby significantly improved strength levels and temperature capability 

could be achieved relative to conventionally processed aluminum alloys. 

Application requirements driving the “nano” aluminum developments were established 

based on large diameter commercial engine fan blade applications. Other airfoils, both 

rotating and stationary, may also benefit from successful development of this technology, 

although the specific property requirements may differ. Conventional fan blade materials 

typically include polymer matrix composites, or titanium. The choice in materials is often 

driven by diameters. Hollow titanium blades have also been used by some engine 

manufacturers. Other rotor and stator airfoils are frequently composed of titanium, 

aluminum, or polymer matrix composites. Operating conditions for large diameter 

commercial fan blade applications require high strength, fatigue resistance, ductility, 

erosion and impact tolerance, thermal stability, and environmental resistance. Such parts 

are considered critical to the operation and safety of the engine. Relative to conventional 

fan blade material choices, the aluminum material system being developed in this study 

was intended to be lighter in weight compared to titanium and lower in complexity and cost 

relative to a polymer matrix composite. Alloy development efforts were driven primarily by 

the need for improvements in ambient and elevated temperature yield strength, 

maintaining substantial ductility for impact tolerance, and ensuring microstructure stability 

to intermediate temperatures. Specific property goals used to guide Phase I aluminum 

alloy foundation development efforts were: 

1) ambient temperature strength levels of 90ksi (610Mpa), 

2) ambient temperature ductility of at least 5%, 

3) strength at 280°F (140°C) of 60ksi (410Mpa), and 

4) thermal stability to 300°F (150°C). 

These requirements were established to guide selection of general strengthening 

approaches and candidate alloy systems. Significantly more detailed property 

requirements would need to be assessed in subsequent phases of the project when simple 

alloying and strengthening concepts are to be combined into more complicated candidate 

alloy systems. 

A. Subtask 3.2.1: Nano Phase Aluminum Alloying Concepts 

Efforts in this task involved the selection of basic aluminum alloy compositions for study of 

alloying approaches, investigation of techniques to introduce dispersoids within a rapidly 

solidified aluminum alloy matrix, as well as generation of rapidly solidified materials to be 

consolidated and characterized in Task 3.2.2. Work was performed by GE Aircraft Engines

and GE Corporate Research and, through GE subcontract, by Transmet Corporation. Final 

alloy composition selections were discussed and agreed upon by the project team 

including NASA, GE, OSU, and Transmet Corporation. 

 Alloy and Alloying Technique Selection 

There are two commercial alloy series specifically developed to achieve high strength, but 

neither can maintain high strength in the temperature range from room temperature to 

NASA/CR—2005-213971 4
300oF, as required by the present application. One is the 7xxx-series of alloys which 

derive their strength from fine GP-zone precipitation of a semi-coherent Zn2Cu phase. The 

7xxx-series of “high strength” alloys approach the ambient temperature strength 

requirements of the present application, but their strength falls off sharply with temperature 

and is not unacceptable above 250oF. Temperature capability limits are typically attributed 

to precipitate coarsening and subsequent loss of strength with time at elevated 

temperatures. The 2xxx-series of aluminum alloys have been developed to maintain 

strength to temperatures above 450oF. This series of “high temperature” alloys derive their 

strength mainly from solid solution strengthening via Cu addition. Although GP-zone 

precipitation can also be formed to provide additional strengthening, the strength of the 

2xxx-series alloys is significantly lower than target requirements in this effort for both 

ambient and 300oF temperatures. These trends and the project tensile requirements are 

shown in Figure 2.1.1 

High-strength alloy

High-temperature alloy

300oF+ High-strength alloy

Temperature

Yield Strength, MPa

150oC

620

410

Figure 2.1.1: Aluminum alloy tensile property goals relative to conventional alloys. 

New alloying and strengthening approached are necessary to achieve high strength over 

the temperature range from room temperature to 300oF. The conventional precipitation 

strengthened alloying approaches utilized in alloys such as 7xxx- and 2xxx-type aluminums 

will have to be abandoned or supplemented by new strengthening approaches, Figure 

2.1.2. New alloy composition domains will also need to be explored to take advantage of 

the benefits of novel processing routes such as RS processing. 

Several new alloying concepts were formulated and led to the development of the Phase I 

plan. The primary concept was based on dispersion strengthening with nano-scale 

particles using rapid solidification processing techniques. Due to the thermal stability 

requirement, it was necessary to pursue dispersion phases which were highly stable 

including those which may be formed from liquid state during solidification. Rapidsolidification processing was used to produce nano-scaled particle dispersions with 

sufficient volume fractions and spacings to be effective strengtheners. In one approach, an 

oxide dispersion was considered, due to the increased availability of nano-sized oxide 

powder recently and the identification of a possible low-cost process that could incorporate 

NASA/CR—2005-213971 5
the nano particles into aluminum. In a second approach, two classes of dispersion phases 

formed by precipitation, icosahedral and L12, were pursued due to their desirable thermal 

stability and ability to respond to rapid-solidification to produce fine dispersions of particles. 

At a later stage in the evaluation effort, interesting aspects of the Al6Mn dispersion phase 

were observed in this program, and the Al-Mn system was subsequently pursued in place 

of the oxide dispersion approach. These concepts are described in additional detail in the 

subsequent paragraphs as are a few candidate alloying approaches which were not 

selected for pursuit in this project. 

Commercial

Al-7xxx

Alloys

Commercial

Al-7xxx

Alloys

New

Chemistry

Domains

New

Chemistry

Domains

Zn2Mg precipitates 

are unstable.

Phases stable to 

>280°

F

•Icosahedral phase

• Si

•L12 phase

•Oxides

Use RS processing to

explore new chemistries

containing stable

strengthening phase

Use RS processing to 

explore new chemistries 

containing stable 

strengthening phase

Figure 2.1.2: Schematic showing several candidate aluminum alloying approaches. 

Oxide dispersion in a 2219 matrix

Stable oxide dispersions are used in several conventional mechanically alloyed nickel- and 

iron-based alloys in order to provide elevated temperature strengthening. Matrix 

strengthening is provided by a combination of solid solution and/or precipitate 

strengthening via alloying and dispersion strengthening by the introduction of fine ceramic 

particles in such structures. Reliable introduction of a fine oxide dispersion is complicated 

by several factors including density differences between the dispersoid compound and the 

matrix, high interfacial energies, and complicated solidification processes. Many existing 

oxide dispersion strengthened alloys are manufactured by powder metallurgy approaches

involving extensive ball milling to introduce a fine oxide throughout the metallic matrix. 

Such processing is difficult and costly. In highly ductile alloy systems, low temperature 

milling may be required to be effective. 

An alternate approach was identified by GE whereby fine oxide powder could be 

introduced into molten aluminum in a way that promoted formation of a uniform particle 

distribution in solidified product. This technique utilized the spinning cup process practiced 

by Transmet Corporation. Such dispersions were expected to provide excellent thermal

stability and improved strength. The commercial 2219 alloy was chosen as a base metal 

matrix for convenience and Al2O3 was selected as selected as the dispersoid. The target 

Al2O3 size range was 20nm or less to enable fine particle spacings while maintaining the 

NASA/CR—2005-213971 6
ceramic volume fraction as low as possible to minimize any adverse impact to ductility. A 

relationship between particle size, volume fraction, and anticipated Orowan-type [1] 

strengthening increment is given in Figure 2.1.3. 

0

10

20

30

40

50

60

70

80

90

100

0 12345 6789 10

Volume Fraction Al2O3 (%)

Orowan Shear stress (ksi)

10nm

20nm

30nm

40nm

50nm

100nm

1000nm

Figure 2.1.3: Estimation showing the approximate Orowan [1] relationship between 

dispersoid distribution and potential strengthening benefit assuming non-shearable 

particles. 

Icosahedral phase dispersion

The icosahedral phase was first discovered in aluminum alloys in the 1970’s. It is a 

metastable phase formed by solidification due to the slow diffusivity of certain alloying 

elements such Fe, Ni and Co [2]. It has a complex crystalline structure with 20 faces, 

which can only grow to form “quasicrystals” with cavities, as shown in Figure 2.1.4. Due to 

the loosely packed structure, quasicrystals are known to be effective strengthening 

particles. Furthermore, a large volume fraction (>20%) of fine (<200μm) icosahedral phase 

particles can be produced by rapid solidification processing. A first icosahedral-phase 

strengthened aluminum alloy, nominally Al-7Fe-1.5V-1.5Si [3], was developed by AlliedSignal in the 1980’s with good combination of strength, temperature capability, fatigue and 

corrosion resistance. 

Tohoku University of Japan has also investigated additional icosahedral phase alloys [4] in 

the 1990’s. Several new icosahedral phase systems were identified with attractive 

combinations of ductility and strength. One of the alloys studied extensively by the Tohoku 

University group was Al93Fe3Cr2Ti2 [5]. Figure 2.1.5 shows the yield strength of this alloy 

as a function of testing temperature (data labeled Al-Fe-Ti-Cr alloys). As seen, the 

strength of this icosahedral alloy system is equivalent to that of the 7xxx-series alloy at 

room temperature, but it strengths maintained over a much larger temperature range more 

similar to that of high temperature 2xxx-series alloys. This icosohedral alloy system thus 

shows the potential of meeting the program goals, and was selected for investigation here. 

NASA/CR—2005-213971 7
Icosahedral nano dispersion

in melt-spun Al-V-Fe

100nm

GRC, 2002

“Quasicrystal” cell built 

from icosahedral phase

Figure 2.1.4: Icosohedral phase structure schematic [2] and an example transmission 

electron micrograph from previous GE studies. 

Al-Fe-Ti-Cr alloys

High Temp. alloys

High Strength alloys

Figure 2.1.5: Al93Fe3Cr2Ti2 properties as reported by Inoue, et al. [5] compared to 

conventional high temperature alloys and project strength requirements (red circles). 

L12 phase dispersion

As in the case of Ni3Al strengthening in Ni-based superalloys, L12 phases have been 

identified in aluminum alloys. Several of these phases and their potential strengthening 

benefits have been reported in the literature, for example, Al3Li, Al3Zr and Al3Sc. The most 

successful strengthening phase was Al3Sc [6]. By powder metallurgy processing 

techniques, alloys containing as little as 0.3 wt.% Sc have been shown to exhibit strength 

NASA/CR—2005-213971 8
levels greater than 500MPa. Unlike Al3Li, however, the Al3Sc phase can form by rapid 

solidification or by high temperature annealing above about 575oF (300oC). The Al3Sc L12

phase, as well as the similar Al3Zr phase have the potential of providing high strength up to 

temperatures in the 300oF (150oC) range. A drawback for the Al3Sc dispersion approach is 

the cost impact to the alloy from the current Sc elemental cost. Sc costs in the range of 3 

or more orders of magnitude greater than that of Al are prohibitive. Even with just a few 

tenths of a percent addition, it can increase the material cost significantly. In this program, 

an alloy composition was formulated based on 0.15 wt.% additions of Sc and Zr to the 

icosahedral phase alloy Al93Fe3Cr2Ti2 identified above. 

Al6Mn dispersion alloys

Based on characterization results obtained from the 2219+ Al2O3 dispersion alloy efforts in 

this study, a fine dispersion of the Al6Mn phase was identified at low Mn levels. The project 

team agreed to produce a several Al-Mn binary alloy with three Mn contents to enable 

more detailed understanding of the strengthening effects of the Al6Mn dispersion. A phase 

diagram [7] for the Al-Mn system showing the limited Mn solubility in pure aluminum and 

the stability of the Al6Mn phase to temperatures above the melting point of pure aluminum 

is given in Figure 2.1.6. 

Figure 2.1.6: Al-Mn binary phase diagram [7] showing limited Mn solubility and high 

thermal stability of the Al6Mn phase. 

Final Phase I Alloy Selection

Technical assessment of candidate aluminum alloy compositions was performed and six 

alloy compositions were selected for manufacturing by rapid solidification processing in this 

NASA/CR—2005-213971 9
project. All alloys, with the exception of two additional conventional baseline alloy 

compositions from alloys 7075 and 2219, were chosen such that fine dispersions of 

strengthening particles could be produced within the matrix. Two primary dispersoidproducing approaches were used – introduction of fine, stable Al2O3 into a molten 

aluminum matrix followed by RS processing and formation of highly stable precipitates 

from a super-saturated matrix during solidification, cooling, or subsequent aging after rapid 

solidification processing. A summary of nominal alloy compositions targeted is given in 

Table 2.1.1 below. 

Table 2.1.1: Selected alloy nominal target compositions (wt.%) used for dispersoid alloys. 

Alloy Al Ti Cr Fe Sc Zr other 

Icosahedral Bal. 2 2 3 - - -

Icosahedral+Sc,Zr Bal. 2 2 3 0.1 0.2 -

2219-Al2O3 Bal. - - - - - Al-2219 matrix

Al-1Mn Bal. - - - - - 1%Mn

Al-1.5Mn Bal. - - - - - 1.5%Mn

Al-2Mn Bal. - - - - - 2%Mn

(a) (b) 

Figure 2.1.7: Transmet rapid solidification processing showing (a) melt spinning of flake, 

and (b) centrifugal atomization (Courtesy of Transmet Corporation). 

NASA/CR—2005-213971 10
(a) (b) 

Figure 2.1.8: Typical particulate materials resulting from (a) melt spinning of flake, and (b) 

centrifugal atomization (Courtesy of Transmet Corporation). 

Table 2.1.2: Nominal and measured alloy compositions (wt.%) 

Alloy Chem. Al Ti Cr Fe Sc Zr Mn other

7075 

baseline 

Bar* 86.6 - 0.21 0.14 - 0.013 0.023 6.3Zn, 1.85Cu,

2.58Mg, 0.25Si 

2219 

baseline 

Bar* 93 - - 0.046 - 0.12 0.27 6.43Cu, 0.046Si,

0.089V 

Icosahedral Nom. Bal. 2 2 3 - - -

Casting** Bal. 1.92 1.70 3.05 - - - 0.03Cu, 0.09Si

Icosahedral Nom. Bal. 2 2 3 0.1 0.2 -

+Sc,Zr Casting** Bal. 1.82 1.80 2.82 0.1 0.13 - 0.05Cu, 0.08Si

Al-1Mn Nom. Bal. - - - - - 1 -

Casting*** 98.8 - - 0.038 - - 1.05 0.035Si

Al-1.5Mn Nom. Bal. - - - - - 1.5 -

Casting*** 98.4 - - 0.042 - - 1.50 0.035Si

Al-2Mn Nom. Bal. - - - - - 2 -

Casting*** 97.8 - - 0.042 - - 2.03 0.036Si

* Input bar stock subsequently melted for flake generation 

** Pre-alloyed cast plates subsequently melted for flake generation

*** Cast sample taken from melt during flake generation process.

Phase I Rapid Solidification Processing 

Two rapid solidification processing (RSP) methods – centrifugal atomization and melt 

spinning were selected for generation of material in this study. Both RSP methods, shown 

in Figure 2.1.7, have been previously scaled-up to production by Transmet, although subscale equipment was used for this study. Typical particulate material morphologies 

generated by these processes are given in Figure 2.1.8. The oxide dispersion alloy was

generated using a centrifugal atomization, spinning crucible technique. Solidified material 

NASA/CR—2005-213971 11
was collected as particulate or was splat quenched on a substrate for characterization and 

analysis. Flake materials from the remaining baseline and experimental alloys were 

generated by melt spinning using pre-alloyed bar or cast plates of the target composition.

Materials for the 7075 baseline, icosahedral and Al-Mn alloys were provided to the 

program by GE. For the Al-Mn binary alloys, a single master alloy with 2% Mn was 

generated and was subsequently diluted with pure Al to generate lower Mn content 

materials. The pure aluminum material was chosen to best match the Al-2%Mn master 

alloy impurity levels to enable a direct comparison of Mn compositions. All flake materials 

were generated in an ambient environment melt spinning apparatus at Transmet 

Corporation. As-produced flake was shipped to OSU for analysis of the as-produced 

structure and to GE Global Research for canning and extrusion consolidation. Additional 

cast buttons of the Al-Mn alloys were also produced to enable comparison of phase 

morphologies in the as-cast condition to that of rapid solidification processed material. 

Actual measured chemistries are given in Table 2.1.2 along with nominal compositions for 

reference. 

Process development trials for introduction of a fine Al2O3 ceramic dispersoid into a rapidly 

solidified aluminum were performed by Transmet Corp. where trial runs, 3-5 pounds each, 

were converted to splat quenched and particulate material for subsequent evaluation. A 

total of more than 20 development trials were performed. Characterization activities in 

Subtask 3.2.2 concluded that the process used for introduction of Al2O3 ceramic particles 

was not fully successful and a decision was made to abandon pursuit of the 2219-Al2O3

dispersoid alloy. Results did, however, suggest that an alternate approach could be used 

to produce a dispersion of Al6Mn. The Team decided to replace the 2219-Al2O3 dispersoid 

alloy with three experimental Al-Mn binary alloy compositions. 

B. Subtask 3.2.2: Nano Phase Aluminum Processing and Characterization 

This task is composed of several subtasks which were shared by GE and OSU. GE 

assessed and performed consolidation of rapidly solidified material produced in Task 3.2.1 

to generate bulk materials for characterization and evaluation by OSU. A schematic 

summary of the process is given in Figure 2.2.1. The OSU characterization efforts included 

defining characterization techniques, assessing as-produced material, and performance of 

a heat treat and exposure study to understand microstructural evolution with time and 

temperature. Additional alloy consolidation efforts were also undertaken by OSU in order to 

generate additional material for analysis from flake. A more detailed summary of the OSU 

characterization efforts can be found in the OSU final report to be published following 

completion of the Phase I OSU effort. 

NASA/CR—2005-213971 12
Cold

Compaction De-Gassing HIPing Extrusion

Ribbon

Platelet

Particulate

Melt

Spinning

Direct Extrusion

Figure 2.2.1: Schematic of the aluminum alloy consolidation processing method. 

Consolidation processing to produce bulk nano-phase aluminum materials 

Two consolidation methods were used depending upon RSP type. For the 2219-Al2O3 

alloy, a production-type system was modified so that molten droplets could be collected 

prior to their solidification into powder, as well as collection of particular material. Molten 

droplets were collected on a substrate material and built up to thicknesses on the order of 

about 0.25 inches (0.5mm). So called, splat quenched material was investigated in the asproduced form and to reduce inherent as-produced porosity, after direct rolling. Melt-spun 

flake materials were consolidated by extrusion into bulk material. To preserve the nanophase structure in the bulk material, a low temperature processing was necessary. 

Furthermore, flake materials display large flat surfaces and a thermomechanical process is 

preferred to minimize prior-particle boundary defects in the consolidated material. Shear 

deformation occurring during extrusion was expected to provide more consistent 

consolidation of flake compared to simple hot isostatic press (HIP). 

Oxide dispersion strengthened 2219 aluminum consolidation

Runs included in the centrifugal atomization DOE were generated in particulate and/or bulk 

form for analysis. The bulk, splat quenched material form was considered to be the most 

convenient for characterization efforts. A view of a typical splat quenched material run 

output is given in Figure 2.2.2. Efforts were discontinued on this material system and 

dispersion production method due to difficulties in producing a uniform distribution of 

ceramic particles in the aluminum alloy matrix with the spinning conditions utilized. 

Additional development effort would be required in order to improve the reliability of this 

process and the uniformity of the dispersion type alloy produced. 

NASA/CR—2005-213971 13
Figure 2.2.2: Typical view of a splat quenched 2219 + Al2O3 alloy. 

Extrusion of baseline 7075 flake material

Consolidation of 7075 melt spun flake material was performed by containered extrusion at

elevated temperature with care exercised in removing absorbed H2O absorbed on the 

surfaces of the flake material. The final dimensions of the extruded rod was about 7/8” 

diameter by 110” long, as shown in Fig. 2.2.3. A section from the middle of the extruded 

rod was cut and polished. It showed sound consolidation without any signs hydrogen 

contamination, as also shown in Figure 2.2.3 (top right). The extruded material was then 

sent to Ohio State University for further characterization. As a result of the success of the 

first, and more difficult of the two baseline alloys in the extrusion process, the consolidation 

design of experiments (DOE) was discontinued in favor of providing additional resources 

for extrude consolidation of Subtask 3.2.1 RSP dispersoid alloy flakes. 

Figure 2.2.3: Photograph of the 7075 baseline alloy extrusion and (top right) a cross 

section indicating no gross porosity. 

NASA/CR—2005-213971 14
Extrusion of 2219, icosahedral phase and Al-Mn alloys

The extrusion procedure used for the alloy 7075 baseline material was also used for 

additional flake alloys, but the extrusion can was redesigned to accommodate processing 

of smaller quantities of multiple flake alloy materials. The extrusion runs were focused on 

consolidation of the 2219 baseline material, the two icosahedral alloys, and the three Al-Mn 

alloys to small diameter bar for OSU characterization efforts and limited mechanical 

testing. To obtain the small diameter, the extrusion can was redesigned to allow a group of 

three alloys to be co-extruded. 

Extrusion of both the icosohedral/2219 set and the Al-Mn set resulted in difficulties with 

applying sufficient press ram force to effectively extrude the can and aluminum flake 

materials through the extrusion die. A very limited amount of the Al-Mn alloy extrusion was 

successfully extruded prior to reaching the maximum press capacity. Further extrusion 

efforts were discontinued in lieu of alternate processing identified by OSU. A macro 

photograph of the short extrusion section containing three Al-Mn alloys and the remainder 

of the extrusion can that could not be successfully processed is given in Figure 2.2.4. 

Figure 2.2.4: Photographs of the unsuccessful Al-Mn extrusion at the can side (left) and at 

the extruded side (right) after removal from the extrusion die. 

Al Alloy Characterization 

Characterization efforts were performed by OSU and will be summarized in detail in the 

OSU final report. Efforts are not yet complete as of the writing of this final report since the 

end of the Phase I OSU effort extends beyond that of GE. The characterization performed 

to date clearly indicates the value of using RS processing to convert eutectic-like 

microstructure morphologies to more finely dispersed particles which are, in turn, expected 

to provide significant matrix strengthening. Fine grain structures are apparent in asproduced RSP materials and there is evidence that relatively fine structures are maintained 

through subsequent thermal processing. 

Analysis of the 2219+ Al2O3 alloy splat quenched samples, shown in Figure 2.2.5(a-c), 

indicated that Al2O3 particles were not distributed uniformly at a fine (<1um) size scale by 

the processing. More detailed analysis of the Al2O3 source powder confirmed that particle 

NASA/CR—2005-213971 15
sizes were significantly larger than that originally targeted. Characterization results, 

however, still suggest that the particle introduction technique parameters were not 

sufficient to form a uniform particle distribution. Also, due to the relatively slow cooling rate 

of molten material during splat quench, residual eutectic structures from the 2219 alloyl 

constituents can also be seen. Transmission electron microscope (TEM) analysis, 

however, did point out an unanticipated benefit. Even at relatively low Mn contents (0.3% in 

this case) a fine dispersion of particles consistent with the Al6Mn phase can be formed 

after RS processing and subsequent high temperature aging heat treatment. 

 (a) (b) 

500 nm

 (c) (d) 

Figure 2.2.5: 2219+ Al2O3 produced by centrifugal atomization and splat quenching 

showing (a) non-optimum distribution of ceramic (bright contrasting phase), (b) typical 

eutectic structures in 2219 base metal, (c) presence of fine Al6Mn in splat quenched and 

heat treated material, and (d) a microstructural comparison to a similar Al-Mn alloy 

produced at slower cooling rates as a cast button. 

NASA/CR—2005-213971 16
200nm

(a) (b) 

Figure 2.2.6: Al-Mn binary alloy characterization analysis performed by OSU showing (a) 

Al6Mn particles pinning grain boundaries and (b) ultra-fine grain structures. 

In the Al-Mn binary alloys, it was found via characterization efforts that the Al6Mn particles 

are present in the microstructure and appear to act in several beneficial capacities – 

pinning grain boundaries to enable ultrafine, as-produced grain structures (Figure 2.2.6), 

fine dispersoids which are stable to >750°F(400°C) and which show interaction with 

dislocations as suggested by Orowan-type mechanisms. Examples are shown in Figure 

2.2.7. Fine grain structures are also stable at temperatures as high at 750°F(400°C). 

Characterization efforts being performed by Ohio State University (OSU) have indicated 

that as-produced alloy flake materials display very fine grain sizes in the range of about 

0.1-1 micrometer in size and selected thermal processing can be used to produce fine 

precipitate dispersions in these materials. Comparison of the melt spun Al-Mn materials to 

the cast Al-Mn buttons produced by Transmet as part of this project indicated that melt 

spinning is beneficial in limiting the formation of coarse second phase eutectic structures in 

highly alloy compositions. OSU characterization efforts continue on as-produced flake 

materials, consolidated bulk materials, and similar materials after heat-treat processing. 

NASA/CR—2005-213971 17
1 μm

1 μm

(a) (b) %

1 μm

2 μm

(c) (d) 

Figure 2.2.7: Al-Mn binary alloy 750°F(400°C) exposure effects showing (a) a bimodal 

Al6Mn distribution, (b) effective dislocation particle interaction, (c) a fine micron or sub 

micron grain size, and (d) stability of the fine structure at 750°F(400°C) for 27 hrs. 

C. Subtask 3.2.3 Modeling 

This task is being performed by Ohio State University under contract directly from NASA. 

GE participation in this task is primarily in providing material generated in other tasks, 

consulting with OSU on technical scope and details, and reviewing results. The OSU 

generated model and early analysis of several baseline and Al-Mn alloy compositions 

suggest that significant strength improvements are attainable with an Al-Mn alloy having a 

fine dispersion of precipitates. Results of material characterization efforts by OSU are 

planned to be used as inputs to refine model parameters by OSU. The primary purpose for 

development of the fundamental model is to provided a predictive tool which will assist in 

more accurate and robust alloying and processing parameter establishment for subsequent 

phases of the project. A schematic summary of the alloy and process development cycle 

integrating modeling tools is given in Figure 2.3.1. A high level summary of the OSU model 

architecture is shown in Figure 2.3.2. Modeling effort under the OSU contract are planned 

NASA/CR—2005-213971 18
to continue later than the writing of this report. Additional details concerning the model and 

results will be available in the OSU final report for this effort. 

Characterization

Tools

As-produced

RSP product

Alloying

Approaches Consolidation

Postconsolidation

processing

Properties

and

Service

Exposure

Predicative

Modeling

Development

modification

feedback

RSP process development

Data

Figure 2.3.1: Schematic of the process for utilization of model results in alloy and process 

development. 

General Method is to use scaling relations that contain the physics for a given

process, but are calibrated to data from given systems

Mechanism Algorithms

Recovery / Coarsening Dislocation Release/Flow

Result: Flow Laws

Al-2Mn (RS)

Al-1Mn (RS) 7075 T73

2219 T8

Blue: 10 min exposure, Black: 1 yr exposure

Example of traditional and RS Mn Al Alloys

Simple:

Athermal release

Thermally Activ.

Release

Pslip = exp

−∆G*

kT





 





∆G* = ∆F* 1− fobs

ˆ k 





 





p 



 





τ = q

sμb

λ

d λ

mc

( )= K D( ) T dt

Dislocation recovery and particle 

coarsening are given a unified framework 

by coarsening of length scales, λ. 

Particles may inhibit dislocation

coarsening.

Strengthening mechanisms

Grain Size Strengthening

Solute Strengthening

(coupled to GS strengthening)

Log[particle size(m)]

2219 T8

Al-2Mn (RS)

Service Temp (Kelvin)

Figure 2.3.1: Summary of the OSU model architecture and early results (bottom right). 

III. Technical Summary of the Shape Change Concepts Subtask

This scoping task was performed to establish airfoil geometry shape change requirements 

based on an aerodynamic assessment and to outline materials approaches and system 

concepts to meet these shape change requirements. Aerodynamic requirements are 

primarily establishment of the desired airfoil geometry changes required to maximize 

specific fuel consumption benefit. Results were used to further define the Phase II plans. 

Assessment of engine benefits and definition of configuration concepts was performed 

NASA/CR—2005-213971 19
using the QAT and GE90 Block 4 engine mission cycles as a baseline. The QAT utilizes a 

commercial engine cycle with a number of advanced engine technologies studied under 

other GE Aircraft Engines contract efforts 

A. Component Level Concepts for Phase 1 Preliminary Down-Select 

Conceptually all compression component airfoils could benefit from shape change 

capability in order to improve incidence angles and to set more optimum camber levels for 

off-design conditions. These benefits may result in improved performance, enhanced 

operability, reduced weight, or a combination of all three. Three application classes were

defined to help narrow the focus for concept studies in this effort and to highlight particular 

differences in how shape changing concepts might be applied. The three classes were: 

1) fan rotor blades 

2) booster and compressor rotor blades 

3) stator vanes and static flowpath surfaces 

Fan blades are the most significant airfoil in size and overall impact to engine performance 

and, therefore, presents the best opportunity to impact fuel burn. Since fan blades must 

operate over a wide range of conditions, a single blade shape cannot typically represent an 

optimum geometry for both high power (max climb) and part power (cruise) performance. 

Rather, fan designs typically compromise performance at both ends of the spectrum to 

achieve an acceptable single blade shape solution applicable to all cycle conditions. A 

shape changing fan blade could potentially be tailored such that high power (low camber) 

and part power (high camber) performance can be optimized. If the fan leading edge (LE) 

is actuated open at high power, the increase in flow could be used to reduce fan diameter, 

weight and drag. If the fan LE is actuated closed at cruise, the performance improvement 

could be used to reduce mission fuel burn significantly.

Booster and compressor blades have a smaller impact on engine performance, but can 

play a significant role for operability. The intended shape change for these blades would 

include increased rotor camber at part speed and decreased camber at high speed. 

Operability enhancements could be converted to lower wheel speeds, smaller diameters, 

fewer stages, fewer airfoils, or a reduced dependence on variable geometry. 

Stator vanes and static flowpath surfaces, such as splitters and bleed ports, define the final 

class, which generally would have a smaller direct impact on component performance and 

operability than rotors. Example concepts include actuating a stator LE open or closed to 

better match incidence, actuating a stator trailing edge (TE) open or closed to control rotor 

loading, and actuating a splitter to accept variable bypass ratios. 

Of the three classes, the fan blade class was chosen for further concept development 

because it provides a direct linkage to, and potentially the most significant reduction in 

engine fuel burn. Additionally, the fan blade technical hurdles encountered were 

envisioned to be somewhat similar to those for booster/compressor rotor components. 

NASA/CR—2005-213971 20
B. Fan Airfoil Camber Change Concepts 

Airfoil Geometry Change 

Figure 3.2.1 illustrates the envisioned camber shape change for the fan airfoil. To increase 

aerodynamic efficiency, the airfoil adopts its maximum camber for high speed operation at 

peak power (at take-off through max climb shown in red). At cruise, the blade uncambers 

for maximum part power performance (blue). A first estimate indicates that a camber 

change of ~4° at the leading and trailing edges, respectively, provides a fan efficiency 

cycle performance gain of ~1% over the cruise portion of the entire cycle for a conventional 

commercial fan engine. The camber is defined as the average between the leading edge 

and trailing edge metal angles, where the metal angles are measured relative to the rotor 

axis. A linear increase in the total camber change from 0° at the blade root to 8° at the 

blade tip was required. 

The optimization from take-off to cruise was assumed through an equal (but opposite) 

change in camber at the leading and trailing edges metal angles. Thus, in order to reduce 

the total camber of the blade, the trailing edge camber angle would be increased and the 

leading edge camber angle would be decreased. 

Actuation Concepts 

Morphing or actuating the blade between the cambered and uncambered states can, in 

principle, be accomplished in a number of ways, as summarized in Table 3.2.1. 

Mechanically actuated drives are expected to add unacceptable weight as well as 

degrading the aerodynamic profile of the airfoils. Piezoelectric & magnetostrictive 

actuators are limited to approximately 0.1% recoverable strain and require high fields to 

actuate. In addition, piezoelectric ceramics are brittle and costly to manufacture in any but 

the simplest shapes. Bimetallic couples, which rely on differences in coefficient of thermal 

expansion (CTE) to actuate in response to temperature changes, are limited to 

approximately 0.3% strain (assuming a peak CTE difference of 15x10-6/

o

C and a limit of 

390o

F (200oC) on the temperature change) and are subject to non-recoverable plastic 

deformation (yielding) at strains exceeding this value. 

NASA/CR—2005-213971 21
Figure 3.2.1: Leading and trailing edge angles for one blade cross-section. 

Table 3.2.1: Comparison of airfoil actuation concepts. 

Actuator 

Driving 

Field 

Max. Strain 

[%] 

Max. 

Frequency 

[kHz] 

Mechanical Drive Mechanical N/A 0.001 

Piezoelectric Electrical <0.1 100

Magnetostrictive Magnetic <0.1 10

Bimetallic Couple Thermal <0.3 0.005 

Martensite ⇔ Austenite

SMA 

Thermal 5-10 0.005

Ferromagnetic SMA Magnetic 5-10 5 

NASA/CR—2005-213971 22
To overcome the above-mentioned shortcomings of the actuation schemes, the airfoil 

actuation concept examined in this study will utilize the thermally induced shape-memory 

effect (SME). The mechanism of thermal SME is illustrated in Figure 3.2.2. At its root is a 

crystallographic phase transformation upon heating or cooling the alloy through the its 

transformation temperature. This transformation is accompanied by high-strain actuating 

response. A schematic of the strain response of a shape memory alloy is given in Figure 

3.2.3. A number of material systems have been identified and studied which exhibit shape 

memory behavior over a wide variety of transition temperatures. A summary of some of 

these systems [9-13] and their actuation temperature ranges are given in Figure 3.2.4. 

The most common of the shape memory alloy systems is that of Ni-Ti system. Alloy 

chemistry can be used in many of these systems to controllably affect transition 

temperature [9,14-15] as shown in Figure 3.2.5. 

The airfoil must be actuated between a elastically “relaxed” and “constrained” 

configurations. The first concept considered was to apply an actuator directly to the airfoil 

surface. To limit the length of time in the actuated configuration, a blade optimized for 

cruise performance was chosen as the unactuated state and one optimized for take-off 

was chosen as the actuated state. A schematic showing the effect of initial 

“unconstrained” blade shape and placement of the shape memory alloy on the pressure or 

suction side airfoil surfaces is summarized in Figure 3.2.6. 

A number of design requirements and constraints have been identified for the fan airfoil 

application. The following were used to guide the scoping study:

• Provide desired shape change 

• Reversible (e.g., do not exceed recoverable strain limit ANYWHERE on airfoil or 

actuator) 

• Cyclic capability >10,000 actuation events 

• Actuation time ~1 minute 

• Temperature capability ~50,000 hours at 160°F (71°C) 

• Passive actuation (e.g., temperature-induced) or active actuation with a limited 

instantaneous or average power requirement 

• No adverse effects on system (e.g., airfoil fatigue debit, overloading fan disk, loss of 

aero) 

• Additional weight < 2 lbs/blade 

NASA/CR—2005-213971 23
Figure 3.2.2: Mechanism of thermal shape memory effect (SME). 

Figure 3.2.3: Schematic strain-temperature hysteresis loop for a shape-memory alloy 

undergoing martensite-to-austenite transformation and subjected to constant load (stress). 

NASA/CR—2005-213971 24
-500 0 500 1000 1500 2000

Ag-Cd

Au-Cd

Cu-Al-Ni

In-Ti

Ni-Al

Ni-Ti

Mn-Cu

Zr2Cu(Ni,Co)

(Nb,Ta)-Ru

Transformation Temperature Range [oF] State-of-The-Art SMA’s -500 0 500 1000 1500 2000

Ag-Cd

Au-Cd

Cu-Al-Ni

In-Ti

Ni-Al

Ni-Ti

Mn-Cu

Zr2Cu(Ni,Co)

(Nb,Ta)-Ru

Transformation Temperature Range [oF] State-of-The-Art SMA’s -500 0 500 1000 1500 2000

Ag-Cd

Au-Cd

Cu-Al-Ni

In-Ti

Ni-Al

Ni-Ti

Mn-Cu

Zr2Cu(Ni,Co)

(Nb,Ta)-Ru

Transformation Temperature Range [oF] State-of-The-Art SMA’s -500 0 500 1000 1500 2000

Ag-Cd

Au-Cd

Cu-Al-Ni

In-Ti

Ni-Al

Ni-Ti

Mn-Cu

Zr2Cu(Ni,Co)

(Nb,Ta)-Ru

Transformation Temperature Range [oF] State-of-The-Art SMA’s

Figure 3.2.4: A summary of typical shape memory alloy transition temperature ranges for 

various alloy systems [9-13]. 

212

32

Temperature [oF]

122

-58

Ternary Addition [at.%]

8 12

FeNi

MnTi

AlTi

CoNi

AuNi

ZrTi

HfTi

212

32

Temperature [oF]

122

-58

Ternary Addition [at.%]

8 12

FeNi

MnTi

AlTi

CoNi

AuNi

ZrTi

HfTi

212

32

Temperature [oF]

122

-58

Ternary Addition [at.%]

8 12

FeNi

MnTi

AlTi

CoNi

AuNi

ZrTi

HfTi

Figure 3.2.5: Effect of alloy composition on Nitinol (Ni-Ti) shape memory alloy transition 

temperatures [9,14-15]. Note that alloying additions typically substitute for either Ni or Ti in 

the structure as indicated by the subscripts in the legend. 

NASA/CR—2005-213971 25
Low Temp High Temp

Stress-Free

SMA cool

airfoil Elastically

Constrained

Low Temp High Temp

Stress-Free

SMA cool

airfoil Elastically

Constrained

SMA on 

pressure side

SMA on 

suction side

heat

Figure 3.2.6: Schematic of the effect of “unconstrained” airfoil shape and shape memory 

alloy actuator location on the resulting low and high temperature blade shapes. 

Active Actuation

Fan Blade

System

• SMA actuation

•SMA/blade interface

• heat input controls

• power delivery system

• thermal/heat transfer

Passive Actuation

Fan Blade 

System

• SMA actuation

•SMA/blade interface

• actuation on T only

Full

passive

Passive &

Minimal 

Active

Full

active

High Power reqmts./delivery system weight

SMA actuation at T> Tmax necessary

Heating to T> Tmax to actuate

=> Best application to stators

Reduced power reqmts./delivery system weight

SMA actuation at T< Tmax

Heating to lower T, partial cycle only

(optimize for cruise only)

=> Potential, but complex power system req’d

No power reqmts/delivery system weight

SMA actuation at Ta to minimize cycle impact

No thermal issues

Likely performance impact, eval. Acceptability

=> Cold TO and max climb debits likely

Design Complexity Cycle Complexity

Figure 3.2.7: Summary of potential passive and active shape memory actuation methods. 

For a shape memory alloy actuation system, the actuation system design, in its simplest 

form, would utilize ambient (component) temperature differences during the engine cycle 

as the driver for actuation. This system would be passive in that no separate control 

system would be required and no energy inputs would be needed. The use of such a 

system assumes that the actuated and unactuated airfoil positions correlate directly to 

distinct temperatures and temperature ranges, and that a shape memory alloy with a 

NASA/CR—2005-213971 26
transition temperature lying between these two ranges can be used. Other system 

configurations including a partially and fully active actuation system could also be 

considered. These systems, however, would require heating of the shape memory 

material and an associated power delivery system that would result in both increased 

electrical power and additional engine weight impacts. A summary of various actuation 

system concepts is given in Figure 3.2.7. Particularly for a rotating component, it is 

desirable to utilize passive actuation concepts whenever possible. 

During this first phase of the shape change concept study, the actuation concepts and 

identified shape memory materials systems were considered in assessing the aerodynamic 

benefit of a shape changing fan blade. Mechanical and thermal analysis was performed 

based on several candidate configurations in order to assess the viability of overall shape 

change and actuation configurations on engine performance and efficiency. 

C. Analysis of Aero Benefits 

The GE90-94B fan blade was used as the baseline geometry to evaluate the performance 

effect of cambering/uncambering the airfoil. Performance was calculated using GEAE’s

standard 3D Computational Fluid Dynamics (CFD) Navier-Stokes code, Tacoma, at two 

operating conditions: mid-cruise near 95% corrected fan speed, and at high power near

105% corrected fan speed. Both cases were run on the cruise operating line using 

standard day inlet conditions. 

Various camber changes were studied to maximize fan efficiency at each condition while 

maintaining flow at speed. In the spanwise direction, camber changes were distributed 

linearly tip to hub so that the maximum change occurred at the tip while no change 

occurred at the hub. In the chordwise direction, the camber distribution was maintained 

while the magnitude was increased or decreased. 

At high-corrected speed, fan efficiency was improved by +1.25 pts by reducing both 

leading and trailing edge camber by 2 deg (4 deg total) relative to the baseline. At cruise, 

fan efficiency was improved by 0.72 pts by increasing the leading edge camber by 4 

degrees, with no change to the trailing edge. Overall the blade tuned for high speed 

requires approximately 8 deg less tip camber than the blade tuned for cruise. The linear 

camber change from tip to hub is crude at best, providing only a rough estimate for the 

desired camber change. Further inspection of the results suggests that neither “optimum” 

blade shape had reached its entitlement performance level, and that a more uniform 

camber change from midspan to the tip would offer further efficiency benefits. 

In general, efficiency at high speed can be traded for efficiency at part speed during the 

design process, and so these results imply that fan performance could be improved by >1 

pt across the speed range through well-controlled camber modifications. 

NASA/CR—2005-213971 27
GE90 vs QAT 

The GE90 blade results were used as the basis to estimate the potential benefit of this 

technology for a QAT engine cycle. The QAT features a 2-stage counter-rotating fan with 

suction side bleed on the first stage rotor blade. It was assumed that the shape changing 

airfoil technology would be applied to rotor 1 only since little benefit could be obtained on 

rotor 2. Because suction side bleed acts to reduce the suction surface boundary layer loss 

and shape changing acts primarily to optimize shock position and strength, the two 

technologies have been assumed to be additive. 

For the GE90-94B engine, +1 pt in fan efficiency corresponds to approximately a 13% 

reduction in entropy generated by the fan blade. Assuming the same 13% entropy 

reduction for the QAT rotor1 leads to an overall 6.1% entropy reduction for the QAT 2-

stage fan component. The resultant net efficiency change for QAT is +0.4 pts. The full 

efficiency benefit would apply to a fully active actuation system.

Active vs Passive Actuation 

Significant barriers such as weight, power requirements, and failure modes made a fully 

active shape memory actuation system untenable. As a result, the possibility of using 

passive actuation was studied. GE90-94B mission cycle data was used to determine if an 

actuation temperature could be defined such that the fan blade would actuate to the high 

camber position at low corrected speeds and to the low camber position at high-corrected 

speeds. At corrected speeds below 100%, the fan would benefit from more camber, while 

at corrected speeds above 100% the fan would benefit from less camber. Most of the 

mission time is spent in the “cruise leg” region. It was concluded that virtually any 

actuation temperature selected would result in the wrong blade shape at some operating 

conditions. 

To minimize the power requirement during active actuation of the airfoil, the actuation 

temperature should be set near 520 R (80°F), with a conventional level of camber as the 

baseline (un-actuated) geometry. The airfoil would passively actuate and increase in 

camber below 520 R (80°F) to achieve the cruise performance benefit. However, at climb 

conditions (high speed at altitude) and on cold day take-offs (high speed at low ambient 

temperature), the airfoils would require heating to avoid actuating to the high camber, 

cruise optimized position. The blade surface temperature would need to be increased 

sufficiently to avoid actuation, but only over a small segment of the mission. Once the fan 

corrected speed decreased below 100%, the heating could be turned off, and the blade 

could be allowed to actuate to the high camber position. A fully passive system could be 

employed only if the penalties at climb and cold day take-off conditions associated with the 

high camber blades were acceptable. 

NASA/CR—2005-213971 28
D. Structural Analysis 

Mechanical Analysis 

In a first shape memory actuator design, the change in camber was achieved through the 

contraction of a SMA skin applied over the entire suction surface of the blade. It was

assumed that the SMA induced a 0.5% compressive strain during actuation and that the 

constituents had the properties listed in Table 3.4.1. 

Table 3.4.1: Material properties for SMA and titanium blade. 

E 

(Msi) 

ν κ 

(BTU/hr-ft-°F) 

Blade [17] 16.500 0.33 3.9 

SMA [18] 12.375 0.33 10.4 

These material properties are consistent with an austenite Nitinol SMA and a titanium fan 

blade. Actuation was modeled as a free thermal effect in which εt = αSMAθ = -0.05 (θ is a 

fictitious temperature change) and εt for the fan blade is zero. In order to estimate the 

thickness of the SMA skin necessary to generate the desired camber change, a 

generalized form of the bimetallic strip solution given in [16] is used. The basic steps in 

this solution are provided below. 

First, it is assumed that two metallic plates of equal length and depth are perfectly adhered 

along their long axis. Because no external loads are applied each cross section must be in 

axial and rotational equilibrium. 

M M M Ph

P P P

F P P

z s b

s b

x s b

2

1

0

= + =

∴ = − =

= + =

∑

∑

Here h is the total thickness (h=hb+hs ). Subscripts s and b represent the SMA and the fan 

blade, respectively. Next, it is assumed that each layer must deflect with the same 

curvature, κ. 

κ

κ

b b b

s s s

M E I

M E I

=

=

From the rotational equilibrium equation, 

( ) Es Is Eb I b Ph 2

1 + κ = . 

NASA/CR—2005-213971 29
Finally, a constraint is applied in order to enforce continuity of the deformations across the 

interface. 

ε κ bκ

b b

b

s

s s

s

t h

E bh

P h

E bh

P

2

1

2

1 + + = −

Combining the last two equations, 

ε t + heκ = 0

where he is an effective thickness and is a function of Es, Eb, hs, and hb. For a total camber 

change of θ, 

e t

L h ε

θ





 



 =

where L is the length. This is a nonlinear equation in terms of the unknown hs and must be 

solved iteratively. For the given material properties and a mean blade thickness of 0.37”, it 

was found that a SMA thickness of 0.004” (4 mils) was required. This value was used in a 

2D plane strain ANSYS finite element (FE) analysis using 8 node serendipity elements. As

shown in Table 3.4.2, the results were in good agreement with the predicted analytical 

solution. The 0.5° difference between the leading and trailing edge camber change is due

to the non-uniform thickness of the blade. 

The deformed shaped of the blade is shown in Figures 3.4.1 and Figure 3.4.2. Contours 

indicate the effective stresses (in psi) and indicate that stresses are well below the blade 

yield stress. 

Table 3.4.2: Predicted (analytical) results and actual (FE analysis) results. 

Desired Actual 

Leading edge camber change 4 3.25 

Trailing edge camber change -4 -3.76 

Total camber change 8 7.01 

NASA/CR—2005-213971 30
Figure 3.4.1: Fan blade leading edge after actuation (color contours) and before actuation 

(black outline). 

Figure 3.4.2: Fan blade trailing edge after actuation (color contours) and before actuation 

(black outline). 

NASA/CR—2005-213971 31
Thermal Analysis 

A one-dimensional thermal analysis was performed for this system with convective 

boundary conditions on the suction and pressure surfaces. The temperature at the SMAfan blade interface was assumed to be 390°F (200°C), which is approximately the SMA 

transition temperature. The heat equation was solved for each material and temperature 

and heat flux continuity was enforced across the interface. The result is three equations in 

terms of the suction and pressure surface temperatures (θ1 and θ2, respectively) and the 

power required (to maintain the transition temperature in the SMA). 

( ) 0

1 0

1 0

2

1 2 1 2 0

2 12

1 12

− − + + = 















− − = 















+

+ + = 













 − + 































β θ β θ β β θ

θ θ

κ

β θ

κ

β

θ θ

κ

β θ

κ

β

κ

s b

o

b

b

b

b

b

b

o

s

s

s

s

s

s

s

s

bL

Q

h h

h h

bL

h Q

&

&

These represent, respectively, the heat equation inside the SMA and inside the blade and 

the continuity condition at the interface. θ12 is the interface temperature (390°F or 200°C) 

and θo is the ambient temperature. The film coefficient (β) for the convective contribution is 

a function of the apparent velocity (spanwise location) and temperature (altitude) and was

assumed to be the same for both surfaces. Two extreme cases were studied: take-off 

conditions at the blade root (low temperature, low film coefficient) and maximum climb 

conditions at the blade tip (high temperature, high film coefficient). The input parameters 

and results are given in Table 3.4.3. The power required is the total for all 22 blades. 

Results indicate that significant power is required to enable heating of the shape memory 

material during active actuation periods. 

Table 3.4.3. Results of the thermal analysis for take-off and maximum climb [19]. 

Configuration β θo Q&

(Btu/ft2-hr-°F) (°F) 106 Btu/hr kW

Take-off/blade tip 450 115 10.0 3000 

Maximum climb/blade 

root 

35 40 1.7 500

E. Refined Shape Change Airfoil Structure Concept 

Titanium blade 

To reduce the required power, a second analysis was performed. In this case, thin strips 

of SMA were placed on the suction surface of the blade at discrete locations along the 

span. The power required was assumed a priori to be 100 kW and the total allowable SMA 

NASA/CR—2005-213971 32
width (spanwise) was calculated by linearly scaling the results in Table 3.4.3. This 

approach is only approximate since it neglects any spanwise heat conduction. 

Because convective losses (∝ width) are the major cause of the large power requirement 

and the camber changes are dependant upon the SMA flexural rigidity (∝ thickness3

), it

was proposed that increasing the thickness to width ratio of the strips could substantially 

reduce the power required. For this reason, two bands of equal width (1⁄2”) but unequal 

thickness were used: one 0.005 inches (5 mils) thick placed at the tip and the other 0.0033 

inches (3.3 mils) thick placed at the midspan. This provided the desired the blade tip 

camber change without introducing additional surface area where the convective losses

are the greatest. 

For the same materials listed in Table 3.4.1, a 3D ANSYS FE analysis using 20 node solid 

elements was performed. The blade was idealized as a flat plate with a uniform thickness

of 0.37 inches. Contours of the vertical (z) displacement are shown in Figure 3.5.1 and the 

leading/trailing edge camber change as a function of spanwise location is given in Figure 

3.5.2. 

Figure 3.5.1: Contours of the vertical deflection for a two SMA band plate on Ti. 

NASA/CR—2005-213971 33
Figure 3.5.2: Variation of the camber change along the span in Ti. 

These figures clearly demonstrate that discrete SMA strips can approximate the desired 

camber change (indicated by the dashed line); however, the result is a nonlinear 

distribution along the span. 

Composite blade 

A similar analysis was conducted using the orthotropic properties of a typical composite 

GE90 fan blade as given below.

In this analysis, four strips of equal width (0.25 inches) were placed at L/4, L/2, 3L/4, and L. 

Thus, the total width of SMA material was the same as the previous case. The analytical 

result predicted a required SMA thickness of 0.002 inches (2 mils) that was used for each 

strip in the FE model. 

Contours of the vertical (z) displacement are shown in Figure 3.5.3 and the leading/trailing 

edge camber change as a function of spanwise location is given in Figure 3.5.4. 

NASA/CR—2005-213971 34
Figure 3.5.3: Contours of the vertical deflection for a two SMA band plate in polymer 

composite. 

Figure 3.5.4: Variation of the camber change along the span in polymer composite. 

NASA/CR—2005-213971 35
Figure 3.5.5: Comparison of camber changes between the aluminum and composite fan 

blades. 

Again, these figures clearly demonstrate that discrete SMA strips can approximate the 

desired camber change (indicated by the dashed line). Using more, thinner strips creates

a blade shape that is closer to the desired shape over a large span. Because the 

thickness of these strips is roughly half of that using in the titanium blade, it is likely that the 

power required in order to maintain the SMA transition would be significantly lower for this

configuration. 

Aluminum Blade 

The four-strip configuration was also studied with a blade comprised of a high strength 

conventional aluminum alloy 7075 (E = 10.9 Msi, ν = 0.33 [20]). Since the elastic modulus 

of Al 7075 is significantly larger than that of the composite blade, a thicker SMA layer was 

needed. As predicted by the analytical tool discussed previously, a strip thickness of 0.005 

inches (5 mils) was used. The results for the camber change as function of spanwise 

location are compared to those from the composite blade in Figure 3.5.5. 

Again, it is apparent that regardless of the blade material, the desired camber change 

(indicated by the dashed line) can be achieved through adjustments in the SMA layer. 

F. Shape Change System Risk Assessment 

Aerodynamic analysis of some first order shape change concepts performed as part of this 

study suggests that aerodynamic efficiency benefits may be significant if a shape changing 

NASA/CR—2005-213971 36
fan blade can be implemented. Several actuation concepts have been considered. 

Constraints related to consideration of failed mode impact on flight safety and overall 

power requirements resulted in selection of two shape change airfoil operation methods. A 

more detailed explanation of the constraints is given subsequently. For both operation 

methods, the unactuated blade shape was considered to be the nominal baseline QAT 

blade configuration that is neither optimized for take-off nor cruise. Also, for both methods, 

the actuated blade shape is that for optimum cruise conditions and actuation would occur 

when the temperature is below the shape memory alloy transition temperature. The 

difference in the two methods is that in one, fully passive actuation is assumed whereby 

the blade temperature is the sole determining factor driving when the blade is in the 

actuated position and when it is not, whereas, in the other, operation is largely passive with 

some specific cycle points having active actuation (i.e. heating) to inhibit transition to the 

actuated optimum cruise blade shape at low temperatures. Specific cycle points which 

would likely require such partial active actuation include cold day take-off and top of climb 

cycle points. 

From a failure mode perspective, toggling between the optimized for cruise and optimized 

for high-speed shapes may be unacceptable. If the blade failed in the optimized for cruise 

position (high camber), performance at high speed would be reduced through almost 2% 

lower flow and ~3 pts lower efficiency at speed. Such a severe degradation of fan 

performance would lead to unacceptable impacts on takeoff thrust, EGT, and climb rate. 

Conversely, if the blade failed in the optimized for high-speed position (low camber), cruise 

performance would be reduced by more than 1 pt., leading to a substantial fuel burn 

penalty. Additionally, the low camber position would likely be more prone to aeroelastic 

instability. A lower risk approach may be to specify the nominal blade shape as the 

default/primary position, and actuate to the high camber position at cruise to realize the 

specific fuel consumption (SFC) benefit. An alternate approach could be to specify the 

nominal blade shape as the default position, and actuate to the low camber position at high 

corrected speeds for improved temperature and speed margins. For the risk assessment, 

the nominal, unactuated blade shape was defined as the default QAT baseline blade 

shape and the actuated shape was defined as the high camber, cruise optimized blade 

shape. 

Assessment of actuation methods has indicated that in the anticipated QAT engine mission 

cycle, fan blade temperature cannot be exclusively used to permit a passive SMA actuation 

of the fan blade shape to improve efficiency during cruise. Cold day take-off and top-ofclimb mission cycle points present the most difficult issues due to overlap in the anticipated 

fan blade temperature with that of the cruise condition. Under these two cycle point 

conditions the take-off blade shape would still be required to meet performance and safety 

requirements, but the blade temperature would tend to transition the blade shape to the 

optimum cruise configuration. High level assessment of this and other risks related to 

passive and active actuation systems have also highlighted concerns related to transients 

during transition between take-off and cruise blade shapes, complexity and weight of an 

electrical power delivery system for active SMA actuation, and SMA material transition 

temperature accuracies anticipated for effective blade shape change. 

NASA/CR—2005-213971 37
An assessment of risks associated with each of the two methods – fully active and passive 

with partially active control - was performed in order to more fully characterize the 

difficulties and constraints associated with implementation of such a system. A summary is 

of the top risk items is given in Table 3.6.1. Several risks are common to both the fully 

passive and the passive/partially active actuation methods. Such risks include uneven 

actuation of blades when transitioning between actuation states leading to vibration, noise, 

and loss of performance; overall system complexity and number of failure modes; and the 

possibility of instantaneous thrust changes when blades are actuated. Risks specific to the 

fully passive actuation include potential for max climb and cold day take off thrust debits 

being unacceptable. For the passive/partially active actuation system, the primary risk is 

that the complex, heavy, power delivery system would be required. 

Assessment of the risks associated with the Shape Change Airfoil technology for QAT fan 

blade applications suggest that there are significant design, performance, safety, and 

material constraints which would have to be addressed in order to move forward with this 

technology as it applies to QAT fan blades and the overall QAT mission cycle. It is critical 

that these issues be assessed to determine the feasibility of implementing such a system. 

Table 3.6.1: Summary risk assessment for two shape change fan blade configurations 

G. Implications to the Engine System 

The System Study assessment performed as part of the overall GE IPSFT Phase I 

program examined the overall impact of various technologies to the engine. Inputs to this 

analysis for this project are summarized in Table 3.7.1. Due to the early stage of 

development of this technology and several unknowns that had not yet been explored, 

several assumptions were made to enable an overall assessment. Assumptions are 

detailed in the table. Resulting performance effects are summarized in Table 3.7.2. 

In order to accomplish the shape change, a shape memory alloy strip configuration applied 

to one surface of the blade was used for the System Study assessment. Only preliminary 

NASA/CR—2005-213971 38
assessment of this configuration could be performed under the scope of the Shape 

Changing Airfoil concept assessment effort and this configuration is not considered to be 

optimum. Shape memory alloy shape actuation to change the blade shape was assessed 

and the target configuration assumed that the shape change at cruise could be 

accomplished in a passive actuation mode using ambient blade temperature transitions to 

actuate the shape memory material into the cruise condition. However, due to variability in 

ambient air temperature at take-off and temperatures reached at the top of climb, it was 

determined that some selected active shape memory alloy actuation would be required to 

delay blade transition to the cruise condition during a cold day takeoff and during typical 

top of climb conditions. Several assumptions were used to permit input of data for the 

system study. 

Table 3.7.1: System impact study inputs from the Shape Change Airfoil project. 

Parameter Value Assumptions 

Fan efficiency 

improvement 

(∆ED12) 

0.40 

pt. 

Baseline blade shape for unactuated condition, optimized 

airfoil shape for cruise mission segment. 

System Weight +5 lbs No consideration of power delivery system weight (if 

required). Weight increase due to shape memory material 

added in four bands at 1⁄4 span points and also added 

resulting impact to stator and disk resulting from increased 

blade weight. 

Electric power 

requirements 

12 hp Power required only during active actuation portions of 

engine cycle. Power requirement was spread over the 

cruise portion of the cycle for simplicity of system modeling. 

Table 3.7.2: System study results 

Engine Parameter Estimated Benefit

% Specific fuel consumption -0.25% 

% Fuel burn -0.25% 

% Range +0.25% 

Inputs to the Impact Matrix were made based on the assumptions above and included an 

assessment of as many of the impacts as was possible from the scope of the Shape 

Changing Airfoil concept study assessment. A fan efficiency improvement of 0.40 points 

(∆ED12) was determined based on the ability to modify the baseline QAT blade camber by 

4 degrees into the optimum mission cruise stage blade configuration while keeping the 

standard baseline blade shape under take-off and climb conditions. For the shape memory 

material configuration, the overall impact to the overall system was 5 pounds versus the 

baseline QAT when considering additional weight increases in the rotor and 

stator/containment system resulting from the additional blade weight. No weight impact 

was taken for any electrical power delivery system required for the active actuation system 

for cold day take-off and typical top of climb conditions. Assessment of the overall design 

and corresponding added weight from components needed to route electrical power from 

NASA/CR—2005-213971 39
the engine stator through the rotor to the blades was not within the scope of the Shape 

Changing Airfoil Phase I effort and as a result was considered an unknown. An estimate of 

the electrical power consumption was included based on power requirements for 

resistance heating of the shape memory material. Electrical power would only be required 

during the active actuation portion of the engine cycle, however, for simplicity of system 

level analysis, the total power requirement was spread over the entire engine cycle yielding 

a 12 horsepower impact throughout the cycle. Additionally, it was assumed that other 

factors relating to blade design, power delivery system design, engine performance and 

safety, formation of a robust mechanical bond between the blade and shape memory 

material, and robust electrical and thermal isolation of the shape memory material could be 

accomplished with additional development effort. 

Results in Table 3.7.1 indicate that the 0.5% specific fuel consumption goal in this project 

was not met. Instead a 0.25% benefit was assessed based on a number of significant 

assumptions. 

H. Summary

Scoping of shape changing airfoil concepts including both aerodynamic analysis and 

materials-related technology assessment effort was performed. Three general categories 

of potential components were considered – fan blades, booster and compressor blades, 

and stator airfoils. Based on perceived contributions to improving engine efficiency, the fan 

blade was chosen as the primary application for a more detailed assessment. A high-level 

aerodynamic assessment using a GE90-90B Block 4 engine cycle and fan blade geometry 

indicates that blade camber changes of approximately +/- 4 degrees would be sufficient to 

result in fan efficiency improvements nearing 1%. Constraints related to flight safety and 

failed mode operation suggest that use of the baseline blade shape with actuation to the 

optimum cruise condition during a portion of the cycle would be likely required. Application 

of these conditions to the QAT fan blade and engine cycle was estimated to result in an 

overall fan efficiency gain of 0.4%. 

High-level assessment of fan blade operation temperature ranges for critical mission cycle 

points indicates that passive airfoil shape control using shape memory alloy materials is 

not likely to be sufficient to trigger shape changes at all of the appropriate points in the 

engine cycle. Active control mechanisms would likely be required in using shape memory 

alloy materials in sub-sonic fan blade applications unless expected thrust debits during 

cold day take-off and max climb portions of the cycle can be accommodated in a passive

actuation approach. Structural analysis suggested that actuation strains to achieve desired 

camber changes could be accomplished with shape memory alloys. Tailoring of the 

actuated blade shape is possible through variation in the location, shape (thickness, width, 

length), and the number of discrete SMA patches. However, in order to maximize the 

enhancement, a thorough mechanical and thermal optimization would still be required. 

NASA/CR—2005-213971 40
Assessment of the risks associated with the Shape Change Airfoil technology for QAT fan 

blade applications suggest that there are significant design, performance, safety, and 

material constraints which would have to be addressed in order to move forward with this

technology as it applies to QAT fan blades and the overall QAT mission cycle. It is critical 

that these issues be carefully considered if one is to determine the feasibility of 

implementing such a system. 

IV. Conclusions and Recommendations 

A. Conclusions based on Phase I study 

Based on the Phase I Shape Changing Airfoil project study, the following conclusions were

made: 

1. Melt spun aluminum flake material can be successfully consolidated to bar by 

containered extrusion. 

2. Rapid solidification techniques such as melt spinning have demonstrated the 

capability of forming fine microstructures in several aluminum alloys which can be 

heat treated to yield fine stable particle dispersions if the chemistry permits. 

3. Difficulties in introducing aluminum oxide into molten aluminum led to 

discontinuation of the ceramic dispersion strengthening approach, although 

characterization did point to the benefits of the Al-Mn system which was pursued 

further. 

4. Al alloy characterization efforts suggested that icosohedral and Al-Mn alloy 

compositions may be processed to result in fine particle dispersions which are likely 

to significantly improve strength and temperature capability over conventional high 

strength 7xxx-series alloys. 

5. A Modeling approach developed by OSU focused on linking Al microstructure 

parameters, deformation conditions and tensile/creep strength. Characterization 

results will be implemented in the finalized OSU Phase I model used to refine the 

model. 

6. Aerodynamic assessment indicates 0.4% fan efficiency benefit for QAT using a 

shape changing fan blade concept leading to about a 0.25% specific fuel 

consumption and 0.25% fuel burn benefit. 

7. Mechanical assessment suggests that shape memory alloy materials can be applied 

to a commercial engine fan blade geometry with a relatively low blade set and 

overall system weight impact of the order of 5 lbs. Noting that weight associated 

with a power delivery system had not been assessed and is not included in this

estimate. 

8. Consideration of active vs. passive control and assessment of system risks 

indicated significant constraints to both control methods in application to a shape 

changing fan blade to QAT. 

B. Recommendations based on Phase I Study 

Based on the Phase I Shape Changing Airfoil effort the following recommendation are 

being made. 

NASA/CR—2005-213971 41
1. Continued aluminum development, heat treatment, characterization and modeling 

efforts are recommended in order to enable exploitation of alloying concepts 

established in this project. Validation of strengthening concepts via mechanical 

testing is recommended prior to applying strengthening approaches and resulting 

models to generate more complex alloys. 

2. Other applications of this technology to stators and other engine cycles including 

high Mach flight may be subject to fewer limiting constraints and thus have a more 

likely path to implementation although the performance impact has not been 

evaluated in this study. As a result other applications may be more amenable to

implementation of these shape change concepts to a stator component. Additional 

assessment would be required for these other applications. 

V. Program Schedule 

The Phase I RASER Task Order 23 WE# 3.2 schedule is given in Table 5.1.1 below. 

Table 5.1.1: Overall Phase I project schedule 

VI. References 

1. D. Hull and D.J. Bacon, Introduction to Dislocations, International Series on 

Materials Science and Technology, vol. 37, Pergamon Press, New York, 1984. 

2. K. Hiraga, T. Ohsuna, W. Sun and K. Sugiyama, Materials Transactions, vol. 42, 

2001, pp.2354-2367. 

3. D.J. Skinner, R. L. Rye, D. Raybould and A.M. Brown, Scripta Metallurgica, vol. 20, 

1986, pp. 867-872. 

4. A. Inoue and H. Kimura, in “Aerospace Materials,” edited by B. Cantor, H. Assender 

and P. Grant, published by Institute of Physics Publishing, Bristol, UK, pp. 150-169. 

NASA/CR—2005-213971 42
5. A. Inoue and H. Kimura, Materials Science and Engineering, vol. A286, 2000, pp. 1-

10. 

6. K.L. Kendig and D. Miracle, Acta Materialia, vol. 50, 2002, pp. 4165-4175. 

7. (insert reference for Al-Mn binary phase diagram) 

8. T. Koike, H. Yamagata and N. Kanetake, Journal of Japan Institute of Light Metals, 

vol. 51, 2001, pp. 267-272. 

9. Shape Memory Materials edited by K. Otsuka and C. M.Wayman, Cambridge 

University Press, 1999. 

10. R. Kainuma, H. Nakano, K. Oikawa, K. Ishida and T. Nishizawa, "High Temperature 

Shape Memory Alloys of Ni-Al Base Systems", Materials Research Society 

Symposia Proceedings, 1992, Vol. 246, pp 403-408. 

11. P. L. Potapov, "Martensitic Transformations and High Temperature Shape Memory 

Effect in the Intermetallic NiMn Alloyed with Ti", Metal Science and Heat Treatment, 

1993, Vol. 35, No. 9, pp 520-525. 

12. G. S. Firstov, J. Van Humbeeck, Yu. N. Koval , “Peculiarities of the martensitic 

transformation in ZrCu intermetallic compound - potential high temperature SMA” , 

Journal de Physique IV, 2001, Vol. 11, pp 481-486. 

13. R. W. Fonda, H. N. Jones and R. A. Vandermeer, "The Shape Memory Effect in 

Equiatomic TaRu and NbRu Alloys", Scripta Materialia, 1998, Vol. 39, No. 8, pp 

1031-1037. 

14. A.G.Hundzhua, M.I.Zaharova, A.V.Sorokin, "Martensitic Transformation in Alloyed 

Nickel-Titanium", Metalphysics, in Russian, 1986, Vol. 8, No. 2, pp 38-42 

15. US Patent 5,114,504 "High Transformation Temperature Shape Memory Alloy", 

1992. 

16. Timoshenko, S., “Analysis of Bi-Metal Thermostats,” Journal of Applied Mechanics, 

v 11, pp. 657-660. 

17. Ti-6Al-4V (Grade 5) Material Data Sheet, ASM (asm.matweb.com), 2004. 

18. NiTi Material Data Sheet, Johnson Matthey Inc. (www.sma-inc.com), 2004.

19. Finn S., Personal communication, GE Research Center, 2004.

20. Aluminum 7075 Material Data Sheet, eFunda (www.efunda.com), 2004. 

NASA/CR—2005-213971 43
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NASA CR—2005–213971

E–15289

WBS–22–714–92–50

NAS3–01135

Work element 3.2, Task order 23

50

Shape Changing Airfoil

Eric A. Ott

Propulsion systems (aircraft)

Unclassified -Unlimited

Subject Category: 07

General Electric Aircraft Engines

One Neumann Way

Cincinnati, Ohio 45215–1915

Project Manager, Clayton L. Meyers, Aeronautics Division, NASA Glenn Research Center, organization code PRV,

216–433–3882.

Scoping of shape changing airfoil concepts including both aerodynamic analysis and materials-related technology assessment effort was performed. Three general categories of potential components were considered—fan blades, booster and

compressor blades, and stator airfoils. Based on perceived contributions to improving engine efficiency, the fan blade was

chosen as the primary application for a more detailed assessment. A high-level aerodynamic assessment using a GE90-90B

Block 4 engine cycle and fan blade geometry indicates that blade camber changes of approximately ±4° would be sufficient to result in fan efficiency improvements nearing 1 percent. Constraints related to flight safety and failed mode

operation suggest that use of the baseline blade shape with actuation to the optimum cruise condition during a portion of

the cycle would be likely required. Application of these conditions to the QAT fan blade and engine cycle was estimated to

result in an overall fan efficiency gain of 0.4 percent.