ASSESSMENT OF SHAPE MEMORY ALLOYS FROM ...stress (MPa) 30 ºC strain (%) (a) 100 200 300 400 0 40 80...

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ASSESSMENT OF SHAPE MEMORY ALLOYS – FROM ATOMS TO ACTUATORS –

VIA IN SITU NEUTRON DIFFRACTION

Othmane Benafan

Structures and Materials Division NASA Glenn Research Center

Cleveland, OH 44135

The ASME 2014 Conference on Smart Materials, Adaptive Structures and Intelligent Systems, September 8-10, 2014 – Newport, Rhode Island

https://ntrs.nasa.gov/search.jsp?R=20150002089 2019-08-31T14:09:12+00:00Z

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It Takes a Team… S.A. Padula II, R.D. Noebe, A. Garg, D.J. Gaydosh,

G.S. Bigelow and T.J. Halsmer Structures and Materials Division

NASA Glenn Research Center

R. Vaidyanathan and D. E. Nicholson Advanced Materials Processing and Analysis Center

Materials Science and Engineering Department University of Central Florida

B. Clausen and D. Brown Los Alamos Neutron Science Center

Los Alamos National Laboratory

K. An and H.D. Skorpenske Spallation Neutron Source

Oak Ridge National Laboratory

Acknowledgment • NASA Fundamental Aeronautics Program, Fixed-Wing and Aeronautical Sciences Projects

• Basic Energy Sciences (DOE)

…

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Motivation and Objectives • We examine microstructures of:

• Conventional structural materials by quenching in the high temperature structure and examining at room temperature.

• This cannot be done for SMA’s because of the diffusionless phase transformation (austenite/martensite) cannot be suppressed by quenching

• Shape memory alloys (SMAs) have strong surface effects: thin films

and surface methods (e.g., SEM, x-ray) are of limited use. Neutrons are a microscopic bulk probe: high penetration allows the examination of the interior of bulk materials.

• Neutrons are non-destructive: complete, intact specimens/ components

can be studied in small samples (~mm) or in bigger engineering components (~m)

WE MUST EXAMINE IN SITU AT STRESS AND TEMPERATURE

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Length Scale in Engineering Materials Where Does Neutron Diffraction Fit?

10-10 10-9 10-8 10-7 10-6 10-5 10-4 10-3 10-2nm m mmÅ m

TEM

SEM / FIB

OM

10-1 100

HRTEM / STEM

ATOM PROBE / FIM

NEUTRON / X-RAY DIFFRACTION

STRUCTURAL SCALE(COMPONENTS)

MICRO-SCALE (MICROSTRUCTURES)

ATOMIC SCALE(NANOMATERIALS)

LOAD FRAMES

0

200

400

600

800

0 5 10 15 20

stre

ss (M

Pa)

strain (%)

15%

10%

5%

8%

13%

18%

(b)

0%

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Chemistry

Physics

Engineering

Life sciences

Biosciences

Materials science

Geological sciences

Archeology

Chemistry

Engineering

Materials science

www.n

W. Kockelmanna et al. Courtesy: Mario Bieringer

Applications of Neutron Diffraction

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Neutrons at the Experimental Area

sample

detector neutron beam

0 0,E kk ,E kk 04 sinQ k k 4 sink k sin

2 202

0 2

k kE E E

m02

2

k: wavevector E: energy Q: scattering vector h: reduced Planck constant m: mass (1.67 x 10-24g) : wavelength

2 : scattering angle

Nomenclature

• Now we have neutrons, what next?

• Neutron beam with a known

wavevector (k0) and energy (E0)

• Detect number of scattered neutrons with a wavevector (k) as a function of the scattering function S(Q,ω)

INCIDENT NEUTRON BEAM

DE

TE

CT

OR

DIFFRACTED BEAM

DE

TE

CT

OR

BEAM STOP LOADING AXIS

LATTICE PLANES// AND

d

k0 k

2

n = 2dsin

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1.0 2.0 3.0 lattice plane spacing (Å)

norm

aliz

ed in

tens

ity (a

rbitr

ary

units

)

100

110

111

data and Rietveld fit

difference curve

peak positions

200

210

211

norm

aliz

ed in

tens

ity

d-spacing (Å)

norm

aliz

ed in

tens

ity

d-spacing (Å)

norm

aliz

ed in

tens

ity

d-spacing (Å)

norm

aliz

ed in

tens

ity

d-spacing (Å)

norm

aliz

ed in

tens

ity

d-spacing (Å)

norm

aliz

ed in

tens

ity

d-spacing (Å)

norm

aliz

ed in

tens

ity

d-spacing (Å)

norm

aliz

ed in

tens

ity

d-spacing (Å)

norm

aliz

ed in

tens

ity

d-spacing (Å)

norm

aliz

ed in

tens

ity

d-spacing (Å)

Peak position •Elastic lattice strain •Intergranular strains

Peak intensity •Texture changes •Phase fraction

Peak width •Qualitative information

Neutron Diffraction Data

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Neutron/Synchrotron Sources in the USA

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Neutron and Synchrotron Sources Around the World

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Oak Ridge National Laboratories-SNS

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Los Alamos National Laboratory-LANSCE

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Isothermal Deformation - Loading Actuators

Binary 55NiTi

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Binary 55NiTi d-spacing (Å)

inte

nsity

(a.u

.)

stra

in (%

)lo

adun

load

inte

nsity

(a.u

.)

stra

in (%

)lo

adun

load (

011)

M

(100

) M

(110

) M

(020

) M

(111

) M

(111

) M(1

20) M

(121

) M(1

20) M

(030

) M

(031

) M

(013

) M

(230

) M

(150

) M

(141

) M

1 1.5 2 2.5 3

1 1.5 2 2.5 3planes //

planes

(b)

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300

400

500

600

200 300 400temperature (ºC)

0.2%

offs

et-s

tres

s (M

Pa)

44.14 10330

T

SIMT e

Elastic*

SIM33.09 10

1003T

plT e

Plastic{001}{110}{114}{112}

Slip:

Twinning:

Md

0

200

400

600

800

1000

0 5 10 15 20

stres

s (M

Pa)

strain (%)

Region II

Region III

Region IVRegion I

Ni49.9Ti50.1Room temperature

Self-accommodatedMartensite

Reverse reorientation

Reorientation and detwinning

(20-1)B19' twinning system

Possible slip

Martensite Austenite

• Deformation mechanisms revealed- complexity and multiplicity of mechanisms can’t be resolved another way

• e.g., reorientation planes/limits, stress- induced-martensite region, martensite desist...

O. Benafan, et al., Journal of Applied Physics, 2012, 112, 093510, p. 1–11.

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• No major differences in transformation strains • Large strain evolution (ratcheting) difference

Isothermal Deformation – Where to Load Actuators? Does it Matter?

Loading in martensite Loading in Austenite

O. Benafan et al., International Journal of Plasticity, 2014, 56, p. 99–118.

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SMA Properties – Can they be Optimized for Actuators?

1. Material and Geometry‡ • Binary 55NiTi → = 5.08mm (0.2in) • Stress free transformation temperatures

• • • •

• Effective coefficient of thermal expansion • •

• Effective elastic moduli • •

• Effective Poisson’s ratios • •

* 6

* 6

13.0 10 /

6.4 10 /A

M

C

C

*

*

74

50A

M

E GPa

E GPa

*

*

0.33

0.387A

M

92105

7155

s

f

s

f

A CA C

M CM C

0.10

0.15

0.20

0.25

0.30

0 50 100 150 200 250

heatingcooling

Stra

in (%

)

Temperature (ºC)

*M

*A

0

100

200

300

400

500

600

0 1 2 3 4 5 6

austenitemartensite

Stre

ss (M

Pa)

Strain (%)

As

Mf

Ms

AE

ME

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Transformation Temperatures: DSC vs. Strain-Temperature vs. Neutrons

d-spacing (Å)1 1.5 2 2.5 3

0

10

1

inte

nsity

(a.u

.)

(b)

(c)

tem

pera

ture

(ºC

)

30

heat

ing

cool

ing

230

inte

nsity

(a.u

.)

30

As

Af

Ms

Mf

(100

) A

(110

) A

(111

) A

(210

) A

(221

) A

(211

) A

(011

) M

(100

) M

(110

) M

(111

) M(1

10) M

(111

) M

(102

) M

(030

) M

(202

) M

(320

) A

reta

ined

B19

'

Asneutron

0 40 80 120 160 200

stra

in (%

)

temperature (ºC)

0.1%

in situ

ex situ(a)

heatingcooling

• Transformation temperatures during the reverse transformation measured from strain-temperature and DSC data were found to differ from the actual onset of transformation as revealed from neutron spectra.

• The austenite phase starting to form at ~75 ºC, O. Benafan et al., Scripta Materialia, 2013 68(18), p. 571–574

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Dynamic Young’s Modulus for Ni49.9Ti50.1

50

60

70

80

90

0 40 80 120 160 200

You

ng's

mod

ulus

(GPa

)

temperature (ºC)

cooling(a)

T = 200 ºC/h.

L =50

h =4

w = 3

heating

50

60

70

80

90

0 40 80 120 160 200

You

ng's

mod

ulus

(GPa

)

temperature (ºC)

heating

(b)

T = 765 ºC/h.

L =50

w = 4.9

w

50

60

70

80

90

0 40 80 120 160 200

You

ng's

mod

ulus

(GPa

)

temperature (ºC)

heating

(c)

T = 200 ºC/h.

L =50.2d = 4.95

50

60

70

80

90

0 40 80 120 160 200Y

oung

's m

odul

us (G

Pa)

temperature (ºC)

heating

(d)

T = 200 ºC/h.

L = 50

h = 4

5

• Dynamic Young’s modulus data obtained from the impulse excitation of vibration tests. • The average dynamic modulus of martensite at room temperature was about 70 GPa, but

decreased with increasing temperature with an average minimum value of 60 GPa at ~80 ºC.

O. Benafan et al., Scripta Materialia, 2013 68(18), p. 571–574

ASTM E1876-09

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0.2% Offset “Yield” Stress Behavior of Ni49.9Ti50.1

0

200

400

600

800

0 4 8 12 16

180 ºC150 ºC

160 ºC120 ºC

100 ºC

80 ºC90 ºC

70 ºC60 ºC50 ºC40 ºC30 ºC

stre

ss (M

Pa)

strain (%)

(a)

100

200

300

400

0 40 80 120 160 200

0.2%

off

set-

stre

ss (M

Pa)

temperature (ºC)

(b)

• The onset of inelastic deformation (generally referred to as ‘yield’) in the martensite phase is dominated by reorientation and detwinning mechanisms.

• Decrease with increasing temperature, reaching an averaged minimum value of 140 MPa between 65 and 80 ºC.

• The onset stress then sharply increased in the two-phase region and reached near saturation (with a still slightly positive slope) at 350 MPa near 130 ºC.

• Inelastic deformation over this temperature range (~90 – 130 ºC), which includes the B19'→ B2 phase transition, is attributed to the nearly concurrent operation of stress-induced martensite and plastic deformation.

O. Benafan et al., Scripta Materialia, 2013 68(18), p. 571–574

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Transformation Temperatures: DSC vs. Strain-Temperature vs. Neutrons

d-spacing (Å)1 1.5 2 2.5 3

0

10

1

inte

nsity

(a.u

.)

(b)

(c)

tem

pera

ture

(ºC

)

30

heat

ing

cool

ing

230

inte

nsity

(a.u

.)

30

As

Af

Ms

Mf

(100

) A

(110

) A

(111

) A

(210

) A

(221

) A

(211

) A

(011

) M

(100

) M

(110

) M

(111

) M(1

10) M

(111

) M

(102

) M

(030

) M

(202

) M

(320

) A

reta

ined

B19

'

Asneutron

0 40 80 120 160 200

stra

in (%

)

temperature (ºC)

0.1%

in situ

ex situ(a)

heatingcooling

• Transformation temperatures during the reverse transformation measured from strain-temperature and DSC data were found to differ from the actual onset of transformation as revealed from neutron spectra.

• The austenite phase starting to form at ~75 ºC, O. Benafan et al, Scripta Materialia, 2013 68(18), p. 571–574

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Thermomechanical Cycling of Actuators

(400)H

ZA:[110]B2||[010]H

(001)B2

200nm500nm

0

30

6090

120

150

180

210

240270

300

330

{110}A

latt

ice

stra

in (%

)

0.5

0

-0.5

55N

iTi

NiT

iPd

NiT

iHf

Outcome In situ diffraction Electron diffraction

10 nm precipitates

20 nm precipitates

114M,T

110T002T

112T

110M

002M112M

–0.0

–5.0

–2.5

20 cy

cles

50 cy

cles

0 cy

cles

–0.0

–3.0

–1.5

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• • • •




* 6

* 6

13.0 10 /

6.4 10 /A

M

C

C

*

*

74

50A

M

E GPa

E GPa

*

*

0.33

0.387A

M

92105

7155

s

f

s

f

A CA C

M CM C

0.10

0.15

0.20

0.25

0.30

0 50 100 150 200 250

heatingcooling

Stra

in (%

)

Temperature (ºC)

*M

*A

0

100

200

300

400

500

600

0 1 2 3 4 5 6

austenitemartensite

Stre

ss (M

Pa)

Strain (%)

As

Mf

Ms

AE

ME

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Coefficient of Thermal Expansion: Large Anisotropy

-0.4

-0.2

0

0.2

0.4

20 40 60 80 100

calculation (isotropic average)extensometryself-consistent model

latti

ce s

trai

n (%

)

temperature (°C)

B19' NiTi (heating)

110

001

101

111

020

111

120

solid symbols: neutron datasolid lines: calculation

201

(a)

0.20

0.25

0.30

0.35

0

20

40

60

80

100

20 40 60 80 100 120 140 160

heating (strain%)cooling (strain%)

heating (vol.%)cooling (vol.%)

mac

rosc

opic

str

ain

(%)

temperature (°C)

volu

me

perc

ent o

f B19

' NiT

i (%

)

[1] S. Qiu et al., Appl. Phys. Lett. 95, 141906 (2009)

• Atomic scale measurements of thermal strains

Heating(10-6/ C)

Cooling(10-6/ C)

B19'NiTi

Thermal expansion

tensor components

11 -47.2 -30.8

22 43.8 32.1

33 22.7 27.3

31 29.0 32.4

CTE* 6.4 9.5

CTE† 8.1 10.9

CTE (extensometry) 10.3 9.0

B2NiTi

CTE* 13.0 13.1

CTE (extensometry) 12.4 12.3*isotropic average †self-consistent model

• Outcome • First report on NiTi CTE tensor (monoclinic

martensite) including negative expansion in certain crystal orientations

• Parametric input for most SMA models

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Coefficient of Thermal Expansion: Large Anisotropy

• Similar observation in HTSMAs (e.g., NiTiPt – B19)

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

40 80 120 160 200 240

latt

ice

stra

in (%

)

temperature (oC)

B19 Ni29

Ti50

Pt21

heating

solid symbols: neutron datasolid lines: calculation....... extensometry

011

030

013

121

111

102

120

0

0.05

0.1

0.15

240 260 280 300 320 340

100110111210

latt

ice

stra

in (%

)

temperature (oC)

solid symbols: neutron data. . . . . extensometry-------calculation (isotropic average)

B2 Ni29

Ti50

Pt21

(heating)

O. Benafan et al., unpublished work

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• • • •




* 6

* 6

13.0 10 /

6.4 10 /A

M

C

C

*

*

74

50A

M

E GPa

E GPa

*

*

0.33

0.387A

M

92105

7155

s

f

s

f

A CA C

M CM C

0.10

0.15

0.20

0.25

0.30

0 50 100 150 200 250

heatingcooling

Stra

in (%

)

Temperature (ºC)

*M

*A

0

100

200

300

400

500

600

0 1 2 3 4 5 6

austenitemartensite

Stre

ss (M

Pa)

Strain (%)

As

Mf

Ms

AE

ME

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Elastic Moduli: Hard and Soft Orientations

-400

-200

0

200

400

-4 -2 0 2 4 6

stre

ss (M

Pa)

strain (%)

macroscopic detwinning start


-0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3

-400

-200

0

200

400

100012102100 model012 model102 model100 single crystal012 single crystal102 single crystal

lattice strain (%)

appl

ied

stre

ss(M

Pa)



• Strain anisotropy and texture measurements

• Outcome • First validation of ab initio calculation • Entire compliance matrix, not just a

Young's modulus • Revealed mechanisms responsible for

deflated modulus values obtained from conventional macroscopic tests

# of points R100 128.2 129.8 132.2 6 0.997012 136.0 146.7 145.4 6 0.978102 157.3 152.8 167.1 6 0.999-120 33.8 106.0 101.4 6 0.997121 84.2 116.3 104.6 6 0.996-112 177.6 147.6 165.1 6 0.999-122 120.2 143.7 110.5 5 0.991-111 85.9 130.2 104.7 5 0.999011 175.9 155.7 117.1 6 0.995-121 53.4 122.0 93.3 5 1.000-110 41.0 105.1 78.2 6 0.997

Single crystal Modelhkl

Neutron diffractioncrystalhklE neutronhklE

modelhklE

[1] S. Qiu et al., Acta Mat., 2010

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0

200

400

600

800

1000

0 1 2 3 4 5 6 7

50Ti50.5Ti

stre

ss (M

Pa)

strain (%)

0

200

400

600

800

1000

1200

-0.5 0 0.5 1 1.5 2 2.5 3 3.5

011002

111120

102121

030013

122032

appl

ied

stre

ss (M

Pa)

lattice strain (%)

NiTiPt

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NiTiPt

0

50

100

150

200

250

-0.1 0 0.1 0.2 0.3 0.4

011002

111120

102121

030013

122032

appl

ied

stre

ss (M

Pa)

lattice strain (%)

E011=257.8 GPa R=0.985 E002=138.7 GPa R=0.994 E111=99.2 GPa R=0.997 E120=55.1 GPa R= 0.988 E102=138.3 GPa R=0.993 E121=75.3 GPa R=0.995 E030=173.0 GPa R=0.998 E013=132.3 GPa R=0.988 E122=88.3 GPa R=0.996 E032=218.6 GPa R=0.886

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Optimization of Two-Way Shape Memory Effect • Uniaxial deformation at room temperature

followed by free recovery

• Outcome • Established a quick and efficient method

for creating a strong and stable TWSME • Texture maps were used to determine

deformation modes – correlated with TWSME stability and magnitude (not possible another way)

strain (%)

stres

s (M

Pa)

50

100

150

200

0 2 4 6 8 10 12 1416 18 20 22

0

100

200

300

400

500

600

700

800

900

12

34

56

7

A

B

CD

0.00

3.50

3.00

0.50

1.00

1.50

2.00

2.50

0.00

8.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

0.0

0.5

1.0

1.5

2.0

2.5

0 2 4 6 8 10 12cycle number (#)

= 6%

= 22% = 20% = 18%

= 16% = 14%

= 10%

tran

sfor

mat

ion

stra

in (%

)

(a)

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Shape Setting of SMA Actuators

heating

cooling

pre-strain

1pr

1pr

• In situ neutron diffraction during shape setting of bulk polycrystalline NiTi

• Outcome • Guidelines for shape setting any actuator: stress

and temperature limits for shape setting • Neutrons revealed mechanisms responsible for

the stress generation and relaxation during shape setting.

-0.4

0.0

0.4

0.8

100 200 300 400

100110111210211220221311CTE

(c)

stra

in (%

)

temperature (ºC)

heating

CTE

B2 planes to loading direction

0

100

200

300

400

0 100 200 300 400

stre

ss (M

Pa)

temperature (oC)

2nd shape set

1st shape set

T = 30 ºC

T = 300 ºC

[1] O. Benafan et al. (2012)

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Torsional Characteristics of 55NiTi

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Torsional Characteristics of 55NiTi

0

20

40

60

80

100

300 330 360 390 420 450

T = 5.17 N-m

temperature (K)

(a)

angl

e of

twis

t (de

g)

heatingcooling

0

20

40

60

80

100

300 330 360 390 420 450temperature (K)

(b)an

gle

of tw

ist (

deg)

heatingcooling

T = 0 N-m (TWSME)

0

20

40

60

80

100

300 330 360 390 420 450temperature (K)

(d)

angl

e of

twis

t (de

g)

heatingcooling

T = 0 N-m (TWSME)0

20

40

60

80

100

300 330 360 390 420 450temperature (K)

(c)

angl

e of

twis

t (de

g)

heatingcooling

T = 5.17 N-m

Solid

tube

d-spacing (Å)

Nor

mal

ized

inte

nsity

(a.u

.)

1.0 2.0 3.0


difference curve peak positions

303 K

438 K

{100

}

{110

}{11

1}

{210

}

{221

}

(011

)(1

00)

(110

)

(120

)

(120

)

(111

)

B2 austenite

B19' martensite

(030

)

(e)

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Extension of Neutrons to Novel High Temperature SMAs

33

• Microstructural evolution during isothermal and isobaric deformation of NiTiHf

• Outcome • High work output and dimensional stability • Texture measurements were correlated to the lack

of evolution in this alloy • Confirmed relationship of microstructure and

load-biased tests: From Neutron spectra • Neutrons showed why training of Hf alloy is not

necessary [1] O. Benafan et al. Metall. Trans. A, 43, 4539 (2012)

lattice plane spacing (Å)

(100

)

(021

)

(121

)(102

)

(110

)

1.0 2.0 3.0

norm

alize

d in

tens

ity (a

rbitr

ary

units

)

(111

)


difference curve

peak positions

(a)

(011

)

prec

ipita

tes

2.16 Å

400 MPa thermal cycle 2

0 MPa initial 0 MPa initial

400 MPa no thermal cycle










210

110

120

020

130

012 210

110

120

020

130

012

0 MPa after no load thermal cycle 0 MPa after no load thermal cycle

4.00

3.75

3.50

3.25

3.00

2.75

2.50

2.25

2.00

1.75

1.50

1.25

1.00

0.75

0.50

0.25

0.00

9.00

8.50

8.00

7.50

7.00

6.50

6.00

5.50

5.00

4.50

4.00

3.50

3.00

2.50

2.00

1.50

1.00

0.50

0.00

1

2

3

4

0 100 200 300 400

heating (cycle 1)cooling (cycle 1)heating (cycle 2)cooling (cycle 2)heating (cycle 3)cooling (cycle 3)

strai

n (%

)temperature (ºC)

400 MPa

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-150 MPa/25 °C, Cycle 0 -150 MPa/25 °C, Cycle 1 -150 MPa/25 °C, Cycle 4

-4 MPa/25 °C, Cycle 7 -4 MPa/25 °C, Cycle 8

34

• The role of retained martensite during thermal-mechanical cycling in NiTiPd high temperature shape memory alloy was revealed

• Outcome • Direct correlations were made between

macroscopic changes in actuator performance parameters, and atomic-scale evolution from neutron spectra

• The rate of evolution of texture and volume fraction of the retained martensite plays a key role in the stability of the actuator

-4

-3

-2

-1

0

0 50 100 150 200

Cycle 1Cycle 2Cycle 3Cycle 4Cycle 5Cycle 6Cycle 7Cycle 8

stra

in (%

)

temperature (°C)

(b)

NiTiPd

loading

2.8 2.9 3 3.1 3.2

Cycle 1Cycle 2Cycle 3Cycle 4Cycle 5Cycle 6Cycle 7

B19 (011)

B19 (100)

B2 (100)

d-spacing (Å)

norm

aliz

ed in

tens

ity

(d)

NiTiPd

2.8 2.9 3 3.1 3.2

Cycle 1Cycle 2Cycle 3Cycle 4Cycle 5Cycle 6Cycle 7

B19 (011)

B19 (100)

B2 (100)

d-spacing (Å)

norm

aliz

ed in

tens

ity

(c)

NiTiPd

Extension of Neutrons to Novel High Temperature SMAs

S. Qiu et al.,

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Neutrons can be used to study most actuator forms

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Thank You

ASSESSMENT OF SHAPE MEMORY ALLOYS FROM ...stress (MPa) 30 ºC strain (%) (a) 100 200 300 400 0 40 80...

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Transcript of ASSESSMENT OF SHAPE MEMORY ALLOYS FROM ...stress (MPa) 30 ºC strain (%) (a) 100 200 300 400 0 40 80...