novel niti shape memory alloy films manfred wuttig manfred wuttig tel 301-405-5212 fax...

NOVEL NiTi SHAPE MEMORY ALLOY FILMS

Manfred Wuttig

Manfred Wuttig Tel 301-405-5212 Fax 301-314-9467 Email [email protected]

CONTENTS OF PRESENTATION

Introduction

Novel NiTi Films 1. One Dimensional NiTi Films 2. Gradated NiTi Films 3. NiTi (Ms1)/NiTi(Ms2) Films


Manfred Wuttig


-100 0 1000

100

200

300

Flat

Corrugated

d

Dis

plac

emen

t d

(m

)

Temperature (oC)

0.0 0.5 1.0 1.5 2.0 2.52.5

2.0

1.5

1.0

0.5

0.0

film

substrate

y/c

x/a

Corrugated Films - Complicated Stress Distribution

Report on ”Corrugated ” Film that can be easily analyzed


Manfred Wuttig


Gradated Films - Not Easy to Prepare

Report on Gradated Films prepared by varying substrate temperature


Manfred Wuttig


Report on “Corrugated “ Films that can be easily analyzed


Manfred Wuttig


“Geometrically Novel” NiTi Films

Film

Substrate

L

W

g

ts

tf

wf

(a) 1-D/1-D (b) 2-D/2-D (c) 1-D/2-D


Manfred Wuttig


(a) (b)

SampleNr.

Width of stripwf /m

Distance betweenstripsg /m

Aspect ratiotf/wf

Actual arealdensity

wf/(wf+g) [%]1 2.9 2.1 0.31 58.02 5.4 4.6 0.16 54.03 54 46 0.016 54.04 1000 1000 0.0009 50.0


Manfred Wuttig


Principle of measurement, the cantilever deflection is determined from the change of the resonance frequency, LC1r

L

d C


Manfred Wuttig


-200 -100 0 100 200 300600

700

800

900

1000

1100

1200

1300

No

rmar

ized

def

lect

ion

(

m)

Temperature (oC)

Deflection of four differently patterned NiTi/Si bimorph cantilevers as a function of temperature. All bimorphs were processed simultaneously and identically. aspect ratio = 0.31 aspect ratio = 0.16 aspect ratio = 0.016 aspect ratio = 0.0009


Manfred Wuttig


w

fw

f

-ws-w

s

L

f

L

f

-Ls

(b)

w

s0

w

f 0

L

s < 0

L

f > 0(c)

(a)

Stress analysis of a 1-D / 2-D composite:

(a) unstressed components

(b) components stressed biaxially

(c) patterned film and substrate stressed uniaxially.


Manfred Wuttig


Substrate

SMA

Conceptual martensitic microstructure:biaxially, top, and uniaxially, bottom,stressed SMA films in the two phase temperature region. The light and dark sections represent martensite and austenite, respectively.


Manfred Wuttig


)1(E

)1(E

t

t6

fs

sf2s

f'bi

0

021

021

0

0

0

0

00

00

00

00

00

000

21

00

000

00

21

0

0

0

0

0

0

00

00

000

00

00

000

21

00

00

000

21

Cantilever deflection, Stoney’s Eq.:

Martensite biaxial

Martensite uniaxial

Thermal

T


Manfred Wuttig


Slope of deflection

dT

d'

T tf /wf

*)Modulus

termStrainterm

Ratio

L

'H

'

dT

d

dT

d

Esti-matedratioPest

Experi-mentalratioPexp

Low(Bi)

2s

f

t

t6

sf

fs

E

E

)1(

)1(

T

T > Af

T < As

High(Uni)

2s

f

t

t6

s

f

E

ET

s

f

1

1

0.70.84(A)0.85(M)

Low(Bi)

2s

f

t

t6

s'f

'fs

E)1(

E)1(

dT

TdM )(

As <T< Af

High(Uni)

2s

f

t

t6

s

f

E

E'

dT

TdM

)(

s

f

1

1 '

1.41.28

(avg.)

Evaluation of slopes of deflection and comparison of ratios.


Manfred Wuttig


Report on Structurally Gradated Films prepared by varying substrate temperature


Manfred Wuttig


Martensite/MartensiteComposite NiTi Films

Previous Experiments Show:

The nature of the martensitic transformation depends on the deposition temperature.

Therefore:

It is possible to create martensite/martensite composites by varying the substrate

temperature during deposition.

35 40 45 500

100

200

300

400

500

double layer

385 oC

250 oC

Inte

nsity

/ C

ount

s

2


Manfred Wuttig


250

385

385

385

semi-continuous

discontinuous

continuous

t [min]0 50 100

250

250

T[oC]

10

Variation of the substrate temperature during sputter deposition of the films.

top, semi-continuous,center, discontinuous,bottom, continuous


Manfred Wuttig


-150 -100 -50 0 50 100 150 200

0

2

4

6

8

10

12

14

Q-1 x

10-4

Temperature [oC]

Internal Friction of NiTi double layer film

Deposited while semi-continuously cooling, ;

Single layers deposited at250 deg C,

385 deg C,

-100 0 1000

4

8

12

-100 0 100 -100 0 1000

4

8

12

+


Natural and Artificial Multiferroics

New UMD-based MURI

SMA/SMA Composite With Large Damping SMAs display large damping, up to 50%, at large amplitudes of vibration,

useful for mitigation of earth quake damage -scale R-M SMA Composites display 11% damping at small amplitudes,

useful for mitigation of (small amplitude) mechanical noise Craciunescu/Wuttig, J. Thin Solid Films

Rhombohedral Phase Monoclinic Phase -Scale R-M Composite

=

Temperature [C]

Dam

ping

Q-1 [

%] D

amping Q

-1 [%]


Manfred Wuttig


/g/g

21122211)2(L)1(L)0,0,0(g)2,1,(g

2120

22

/g20

21

/g2

)21(1Q

Analysis of Enhanced Damping


Manfred Wuttig


-150 -100 -50 0 50 100 150 200-100

0

100

200

300

400

500

Dis

pla

cem

ent

[ m

]

Temperature [oC]

Displacement curves of the NiTi double layer films;

Depositions on cooling; semi-continuous, discontinuous, continuous.

Depositions on heating; semi-continuous, discontinuous, continuous.

-200 -100 0 100 200

-0.03

-0.02

-0.01

0.00

M/M

Temperature [oC]

-100 0 100 200-0.015

-0.010

-0.005

0.000

0.005

M/M

Temperature [oC]

Modulus curves for the double layer film deposited on cooling and heatingleft, cooling: semi-continuous, discontinuous, continuous right, heating: semi-continuous, discontinuous, continuous


Manfred Wuttig



Manfred Wuttig


Heating(H)

Cooling(C)

T

Ms385

Ms250

Tx

t

T

Ms385

Ms250

Tx

t

T

Ms385

Ms250

Tx

t

Substrate

t

250oC layer385oC layer

Substrate

t

385oC layer250oC layer

Tx > Ms250, Ms385 Ms250 < Tx < Ms385 Tx < Ms250, Ms385

T

Ms385

Ms250

Tx

t

Dis

cont

inuo

us D

epos

itio

n

T

Ms385

Ms250

Tx

t

T

Ms385

Ms250

Tx

t

Bimorph Temperature(Tx)

Both layers inaustenitic state

Top layer transformsunder constraint

from one side

Bottom layertransforms under

constraint from oneside

Both layers inaustenitic state

Bottom layer transformsunder constraint from

both sides

Top layer transformsunder virtually no

constraint

Deposition Type

No ModulusDefect


Manfred Wuttig


Heating(H)

Cooling(C)

Substrate

t

250oCt layer

385oCt layer

Tx > any Mst Tx = Mst Tx < any Mst

Con

tinu

ous

Dep

osit

ion

Bimorph Temperature (Tx)

All t layers inaustenitic state

t layers transformcontinuously under

constraint from one side

All layers inmartensitic state

All t layers inaustenitic state

t layers transformcontinuously under

constraint fromboth sides

Top t layer transformsunder virtually no

constraint

Deposition Type

Substrate

t

385oCt layer

250oCt layer

T

Ms385

Ms250

Tx

t

T

Ms385

Ms250

Tx

t

tt T

Ms385

Ms250

Tx

t

T

Ms385

Ms250

Tx

t

T

Ms385

Ms250

Tx

t

t T

Ms385

Ms250

Tx

t

t

LargeDisplacement

LargeDamping


Manfred Wuttig


SUMMARY

Two Kinds of Novel NiTi Films:

1. 1-D Films;large displacement

2. Martensite/Martensite Films;large displacementlarge damping


Manfred Wuttig


COLLABORATORS

Kiyotaka MoriGrad. StudentPanasonic Res./Boston

Corneliu CraciunescuResearch Associate,U. Timisoara

Supported byOffice of Naval ResearchNational Science Foundation


Manfred Wuttig


Ehemaliger Dresdner,Anhänger des damaligen DSC: mehrmaliger Deutscher Meister, Heimat-mannschaft von Helmut Schön, des Trainers der Deutschen Fussballmannschaft.

novel niti shape memory alloy films manfred wuttig manfred wuttig tel 301-405-5212 fax...

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