Some
`
`Applications of
`
`Shape—Memory
`
`Alloys
`
`C. M. Wayman
`
`University of Illinois
`at Urbana-Champaign
`Urbano. Illinois
`
`6M
`
`fly Kr
`
`
`And the LORD said unto Moses.
`
`"What /S that in
`
`your hand?" And he said. “A rod."
`Then HE said. "Cast It on the ground." And he cast
`it on the ground and it became a serpent: and Moses
`fled from it.
`And the LORD said unto Moses.
`
`"Put forth th/ne
`
`hand and take it by the tail. " And he put forth l’l/S hand
`and caught it. and it became a rod in his hand.
`
`OLD TESTAMENT
`
`Exodus, Chapter 4:2-4
`
`
`SUMMARY
`L'ses or potential uses of shape memory alloys fall into
`industrial. energy and dental/medical categories. These
`various applications are considered after a brief discusston
`of the nature of the shape memory effect and other interest-
`ing properties in shape memory alloys. Most applications
`lnL'OlL‘E’ NiTi-type and Cu-based alloys,
`the latter being
`relatively inexpensive to produce and fabricate into numer-
`ous rorms.
`
`NATURE AND MECHANISTICS OF THE
`SHAPE MEMORY EFFECT
`
`The shape-memory effect lSMEl can be described as fol-
`lows: basically, an object in the low-temperature. martensitic
`condition when it is deformed and the stress then removed
`will regain its original shape when heated. Strains typically
`6—5 may be completely recovered. The process of regain«
`ing the original shape is associated with the reverse trans-
`tormation of the deformed martensitic phase to the higher
`temperature parent phase.
`Many materials are now known to exhibit the shape-mem-
`ory or “marmem” (martensite, memory) effect: a partial
`Eist includes the alloy systems CLi-Zri. Cu-Zn-Al, Cu-Zn-Ga.
`Cu-Zn-Sn. Cu-Zn-Si. Cu-Al-Ni. Cu-Au-Zn. Cu-Sn. Au-Cd.
`_\'i-Ti. Ni-Ti-X (X = ternary element). Ni-Al. and Fe-Pt.
`These alloys are all ordered (both parent and martensite)
`and exhibit a crystallographically reversible. thermoelastic
`martensitic transformation.
`Substantial progress has recently been made in under-
`standing the nature of SME. As is well known. a crystal at
`the parent phase will
`transform into many orientations
`plates or variants) of martensite on cooling.
`Ideally. 3
`angle crystal of the parent phase will form '24 orientations
`t martensite on cooling between the Mt. and M‘, tempera-
`Utes. But when this multi-orientation configuration of
`martensite is deformed. a single orientation of martensite
`exentually results because of twinning and the movement of
`LE'l'Ealn martensite intertaces.
`It has been shown that the
`twins which form in the martensite are simply other orienta-
`tions Ivariantsl oi martensite: thus twinning can convert one
`orientation ot martensite to another. The same thing happens
`\vnen martenSite/ martensite lntertaces move under stress:
`one orientation grows at the expense of another. In the tinal
`.‘inaIvSis.
`the single remaining orientation 0t martensite is
`the yariant whose “shear" or shape deformation Will permit
`the maXimum elongation of the specimen in the direction
`'OL‘RNAL OF METALS ' June 1°80
`
`oi
`
`the tensile axts.
`Although the original single crystal of the parent phase
`transinrms into many tup to 3-H orientations of martensite.
`the reverse does not occur. Instead.
`the Single crystal of
`martensite obtained trom deformation below the M,
`tem-
`perature transforms. on heating.
`to a single orientation of
`the parent phase. This is a consequence of the relative sym-
`metries involved and the necesstty to maintain ordering. In
`other words.
`the highly symmetric (usually cubic! parent
`phase has many cntstalloeraphically equivalent prinmpal
`axes tor the lattice change ilflain distortionl Which will thus
`lead to the many variants of martenstte which are obsewed.
`On the other hand.
`the relatively unsymmetric martensite
`leg. monoclinic in Cu-Zn-Al alloysl does not enjoy such a
`multiplicity ot choices. and only a single variant ofthe parent
`is usually nucleated during the reverse martensite-to-parent
`transformation.
`In essence.
`the Single crystal of martensite
`"iinshears" to term a single crystal oi
`the parent. and this
`"unshearing" during reverse transitirmation restores the
`spemmen to its original shape. This sequence is metallograe
`phically depicted in Figure l.
`The above account appears to be generally valid. irrespec-
`tive of the alloy system or martensite crystal structure.
`
`OTHER INTERESTING PROPERTIES
`OF MARMEM ALLOYS
`
`
`
`)—._+'—v.a‘/
`
`Shape—memory alloys have interesting {imperues and
`characteristics in addition to the shape-memory elfect,per
`.se. As will be described later. excesstvely deformed (some
`130‘r strain. and well beyond the limit of shape-memory re-
`coverable straini martensittc NiTi alloys have unusual elastic
`properties. When many of the martensltic Cit-based alloys
`are continually deformed beyond the single-crystal marten-
`site stage. a new rimrtensue phase is generated. Le.
`a
`stress-induced martensite-to-martensite
`transformation
`occurs. This successive mode of martensite deformation
`allows recoverable strains ot more than 179‘. Shape-memory
`alloys are also excellent damping materials. The relative
`ease ot movement "at
`internal boundaries. such as marten-
`site-martenstte boundaries. under a small stress is strongly
`attenuating. Finally.
`ti "two-way" shape memory can be
`programmed into various memory alloys by appropriate
`-tre5s and» or thermal cycling, Once this conditioning has
`been achieved. a spectmen will spontaneously "bend" when
`the parent transiorms into martenSite. and "undead" to the
`initial shape ounnty the reverse transiormation.
`
`[:0
`
`
`
`
`
`COOK
`
`Exhibit 1008-0001
`
`COOK
`Exhibit 1008-0001
`
`

`

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`INDUSTRIAL APPLICATIONS OF
`300 :: usmz sa_Lratia.i Civtn:
`tessiullx at depths up (L
`SHAPE-MEMORY ALLOYS
`techniques.
`taking a pre-cnilled fitting down in the le'ln‘.‘
`chamber For Broken sunsea piping. SME fittinEs are jUSIl-
`Fasteners and Couplings
`lied by speed and ease 0! installation compared with other
`One oi
`the earliest Widespread applications of 531E was
`techniques and by no necessny to rely on operator skill.
`Raychem Corporation's (Menlo Park. Calif.)
`introduction
`Raychem has also developed a "Cryocon" shape-memory
`oi
`tubing or pipe couplings which shrink during heating.
`type electrical connector particularly suited for multicon-
`Typical of such NiTi-type couplings are those used for
`nector electrical plugs.
`.
`connecting aircrait hydraulic lines. The couplings are ex-
`Extensive research and development on .\'iTi and NiTiX
`panded ‘4‘? in the martensitic condition at liquid-nitrogen
`ternary alloys is also being conducted at the Brown Boveri
`temperature.
`then placed around the tubes to be mined.
`Research Center in Baden. SWitzerland.
`During warming to room temperature. they contract. produc-
`Raychem recently introduced a new line of Cu-based alloy
`ing a tight seal. The use of such fittings avoids metallurgical
`heat-shrinkable fittings in addition to other fasteners and
`degradation which can result from welding or brazmz. and
`devices. These dEVICES can be provided in the field in the
`avmds damage to the aircraft "skin." Over 300.000 such high-
`idetormedi martensitic condition at room temperature and
`pertormance connectors have been used in U.S. Navy air-
`applied Simply hi: heating.t
`them with a propane torcn.
`craft. With no reported failures.
`Figures .5-5 are examples snowing a coupling. retainer. and
`Similar NiTi-type fixtures have been used extensively for
`clamp; and Figures 6 and T are photographs of a clamp and
`plumbing on submarines and surface ships during the past
`ti seal made of a Cu—based SME alloy. Figure 8 shows a
`five years by the British Royal Navy, and within the past
`Clamp and expander. demonstrating that the engineering
`two years by the U.S. Navy for a variety of surface ships; an
`parameters for the Cu alloys have been well worked out.
`example is shown in Figure ‘2.
`Additional fasteners. clamps, plugs.
`rivets. etc.. will un-
`The size of NiTi-type fittings has been increased consider-
`doubtedly appear in the near future.
`including plugs for
`ably recently. and fittings which join carbon-steel subsee
`nuclear reactors which will eliminate welding.
`pipe up to six inches in diameter have been installed suc-
`
`
`
`Figure 1. Optical micrograph: showlng
`a) numerous orientations oi manensite
`in as-transtormed Cu-ZneGa alloy. b)
`the “coalescence" of variants upon
`stressing. c) nucleation at only a single
`variant ot
`the parent phase during
`heating, and d)
`the original single
`
`crystal at the parent phase.
`
`
`
`
`
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`COOK
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`Exhibit 1008-0002
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`COOK
`Exhibit 1008-0002
`
`

`

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`Figure 2. Bank 0! hydraulic piping on the USS Pelellu installed
`with heat-shrinkable NlTl-lype couplings. (Courtesy Raychem
`Corp.)
`
`
`Figure 5. Clamp or crimp made lrom Cu-based shape-memory
`alloy. (Courtesy Raychem Corp.)
`
`
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`RECOVERED CLAN?
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`Figure 3. Tube or pipe coupling made from Cu-based shape-
`memory alloy. (Courtesy Raychem Corp.)
`
`
`Figure 6. Clamp made irom Cu-based shape-memory alloyl
`(Courtesy Raychem Corp.)
`
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`:Icure 4. Retainer made lrom Cu-based shape-memory alloy.
`:ourtesy Raycnem Corp.)
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`Figure 7. Disc seal made lrom Cu-based shape-memory alloy‘
`(Courtesy Raycnern Corp.)
`
`COOK
`
`Exhibit 1008-0003
`
`COOK
`Exhibit 1008-0003
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`

`

`new. Mme «t .
`
`
`
`Numerous patents have also iieen liled tor \‘arious 531E
`UEV'ICES not
`\et been marketed.
`:UCh as mechanisms lUr
`plaitorm motion. pumps Ior fluids. and thermal warnin!
`dent-es which can be attached to containers used tor shipping
`relrieerated biological materials sucn as human hlood
`
`20
`
`Betalloy
`aim_______=__.
`
`Thermomechanical and Thermostatic Devices
`Substantial eiiorts in developing Cu-‘oased shape-met:
`nri allows have neen made h)”
`the Delta Memorv Mela.
`('iimpanv iSull'olk. England). They have developed a ranee
`nt
`t'u-Zn-Al 531E allovs with emphasis on thermostats.
`controls tor heating and cooling equipment. automotive
`control devices. and actuators tor equipment ranging trom
`L'reenhouse windows to tire doors. Many of these prototypes
`have been cvcled a half-million times or so With no observ-
`able latizue.
`'t'reep." or change in deflection characteristics
`Future H shim-5 an actuator tor greenhouse W'lnduwe. has:-
`i‘nllv a F-prll'lE-it‘laflfld hinge containintt a bias EPTmE and .27
`531E spring. Beiow lh’l'.
`the SME spring is in the ct:
`iracied iniartensiitici condition and the window is clean.
`When the temperature rises. the shape-memory sprine oven
`comes the restraining bias spring. and at 25°C the Wlndt)“
`is
`lully opened. The windOW l5 automatically pulled shut
`when the temperature falls. As expected. the hysterems (it
`an unloaded actuator is some til—15°C. but
`this can be
`compensated for bv torctng the actuator to work against a
`11135 spring. Delta has proposed similar devices to open fire
`doors. actuate ventilators in factories. open radiator vents
`in diesel
`trucks. and control vents in warm-air heating
`svstems.
`
`Another SME spring-actuator/ bias-Spring device is
`thermostatic radiator valve for residential hot-water heatint
`systems iFigure 101. As the temperature in a room increases.
`the actuator expands. overcomes the force of the bias spring.
`and closes the port of the valve on the hot water line of the
`radiator system. The temperature can be adjusted by rotating
`the top head assembly. which alters the compressmn ol‘ the
`bias spring.
`:Such regulators are comparatively inexpenswe
`and have a much faster system response time. With a proper
`bias spring. thermal hysteresis can he held to LEC“ There
`is a remo e-control verston of these valves.
`Another Delta device. an automotive clutch l‘an lFir.“
`11!. ‘uses an SME actuator in the form of a helical spri.
`which is biased against a set of four steel leal' springs. The
`SME actuator coil engages a clutch which turns an automo-
`tive engine l'an when the "air-oft" temperature exceeds a
`certain Value. typically- 53°C: the actuator cloaes the clutch
`plate until
`the temperature is under control. At
`low tEI'rl-
`neratures.
`the Ian idles at
`"“350 rpm. At higher tempera-
`turesfthe clutch t'an speeds up sufficiently to cool the Ei‘lEll’le
`assembly. If this speed is less than engine speed. the clutch
`larl Wlii slip. Thus the l'an does onlyr as much work as rcqutred
`and. accordingly-saves energy. Such a device has been roati
`tested for 20.000 miles. and indications are that
`it WOUJC
`operate an additional 60000 miles. The clutch fan was Dl'l.“
`posed in order to reduce engine noise {at idlinel and fuel
`consumption ibecause it removes the energy loss from the
`Ian when it
`is not required to cool the enamel.
`Another automotive application of Cit-type SME allo.“S
`concerns the carburetor. In this case. atmospheric pollution
`is minimized and fuel consumption optimized by compensat-
`inf.r for tool L'iscostty. A simple jet made ol‘a Cu-Zn-Al SME
`alloy E5 inserted in a Stromhera-type carburetor. As the fuel
`warms. tin orifice reduces in hilt? anti thus tiielers the ctirrcr'
`
`l.‘i
`‘-"‘l."..'l}" Figure 31 “ii"lnkl’fi
`ilm 'Ilil‘rlnrl'f'iil'l'll‘lf
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`Note otii'ticuiam the IBCiUL‘LIOH :i. [U :llliarillll
`.ii
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`tart-determined time after no t'iiemt‘
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`Vii-"W ["1 show -'-I room-temperature thermnhtl‘tl
`i'Iii'lH'i'l
`dcswneo in Delta. This control construe iii an 5MP". actuator
`iprtnfl and mus spring mounted to a standard microswitrfi
`With 'd simple aoiustment tor temperature. A similar met-nu
`italic tirinirioie is involved 1n the use or an 551E. elemei:
`'
`sewitcr'i
`rill eiectricallv-nperated tea kettles once the '4
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`COOK
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`Exhibit 1008-0004
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`Leverage ratio (all)
`
`Figure 8. Clamp and expander made from Cu-based shape-
`memory alloy. {Courtesy Raycnem Corp.)
`
`
`
`Figure 9. Greenhouse window control incorporating a Cu-besed
`shape-memory alloy. (Courtesy Delta Memory Metal Co.)
`
`
`
`Figure 10. Thermostatic radiator valve incorporating Cu-based
`shape-memory alloy actuator spring. (Courtesy Delta Memory
`Metal Co.)
`
`COOK
`Exhibit 1008-0004
`
`

`

`W , y..,,._~ .... .
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`.maa...a.-_a_itWWW-wane t
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`
`the SME ere-
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`l'illed.
`the kettle bUliS drv or [5 ..tit
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`boils
`ment 1: heated. SWItChlnE ml
`the kettle,
`Other examples oi Cu-Zn-Al SME devices are the tuitular
`and coil-type torsion actuators shown in FIEUI'ES l4 and 13
`in the “closed" and "open" posttions. A somewnat similar
`line nl
`i"u-Zn-.-\l SME devices is beine developed by .\'.\‘.
`Bekaert in Zwevegen. Belgium. but they have not yet been
`introduced in the ['15,
`The above discussion emphasizes manv existing thermo-
`
`I,‘Ii-bti_~.ea
`thermostatic JDpllCflthnS oi
`tina
`nechaliical
`531E niin'vs. More \t'ill surely ltliiUW. cunSiderinE the Ii‘lEX'
`itensn'eness (ll sucn masses Lind their ease ()I
`labrlcation.
`Htiwex er. such ullm's are subiect to aging eitects and cannot
`tvt'iicullt operate indetinitelv when the
`‘upper‘ tempera-
`ture is
`\l.3ll°(‘ at more. The nature at
`the aging ett'ects
`\t'nic'n cause aeteriuratinn m the shape memory remains to
`be determined. Higher operating temperatures are expected
`in the iuture through alloy development,
`
`
`
`Figure 13. Room-temperature thermostat control using a Cu-
`based shape-memory alloy spring. (Courtesy Delta Memory
`Metal Co.)
`
`n
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`Figure 11. Automotlve clutch tan with heat-energized actuator
`made tram a Cu-based shape-memory alloy. (Courtesy Delta
`Memory Metal Co.)
`'
`‘
`
`,/Fuel Metering Needle
`
`Jet Orifice Dior? PF.
`
`Steel
`Brass or Stainless
`Jet Orifice insert
`
`
`
`S.M.E. Brass Ring
`(Conditioned to contract
`on heating)
`2 Brass Body
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`60'
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`Figure 14. Tubular torsion actuator made tram Cu-based shape-
`memory alloy. (Courtesy Delta Memory Metal Co.)
`
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`Figure 12. Carburetor jet assembly with variable orifice con-
`trolled by a Cu-based shape-memory alloy. Note the reduction
`of CO emissson by using the SME compensated let. (Courtesy
`Delta Memory Metal Co.)
`
`lUL’RNAL OF METALS 0 June 1080
`
`Figure 15. Coil-type torsion actuator made from Cu-based
`shape-memory alloy. (Courtesy Delta Memory Metal Co.)
`
`COOK
`
`Exhibit 1008-0005
`
`COOK
`Exhibit 1008-0005
`
`

`

`
`
`Recording Pen Drive Unit
`.\lass.i has developed a
`The Foxboro Company (Foxboro.
`simplilied sen'omechanism to drive recording pens and
`indicating-pornter assemblies. The servodriye unit (Figure
`16! contains a _\'iTi Wire maintained under tensile stress.
`The input signal is converted to a current which is induced
`into the SME Wire. the thus-heated Wire changes its length
`and moves a connected lever. This dev1ce eliminates many
`moving parts and is extremely reliable. Over 500.000 such
`units have been produced since their introduction in 1972.
`
`ENERGY APPLICATIONS
`
`,.
`
`That large stresses are generated during the shape-memory
`effect has been known for some time. For example.
`in .\'iTi
`alloys stresses as high as 100.000 psi are created by the re-
`verse transformation of
`the deformed martensite to the
`memory configuration during heating. Such stresses are an
`order of magnitude higher than those necessary to deform
`the martensite at
`lower temperatures. Thus. heat can be
`used to create a mechanical force which can do work. Figure
`17 illustrates the principle involved.
`
`
`
`Figure 1G. Servodrive unit using NlTi wire actuator. (Courtesy
`Foxboro Co.)
`
`Figure 17. Schematic of heat engine
`application 01 a shape-memory alloy.
`
`Numerous neat engines built in the past few vears typical;
`operate between two iixed temperatures Iusually maintainer
`by two water reservmrsi and have modest efficiencres u:
`4—6‘. when operated at room temperature and above. The}
`are consequently well suited to extract heat
`from “low-
`grade" energy sources such as industrial coolant water. dis»
`charge water
`trom nuclear
`reactors. geothermal sources.
`and solar heated masses.
`
`DENTAL AND MEDICAL APPLICATIONS
`Orthodontic Dental Arch Wires
`'L'nitek Corporation (Monrovia. Califi now extensiyer
`'- marKets an orthodontic dental arch wire made from a .\'i".
`alloy. This arch wire. attached to bands on the teeth. is “(n
`| replacing the traditional stainless steel arch wire in many
`' cases. Since its introduction about 2‘.- years ago. over 5.000
`ot
`the estimated 6.500 orthodontists in the U.S. have used
`this device tor straightening teeth.
`In contrast
`to the other SME devices mentioned in this
`report. the dental arch wire is used in the martensitic con-
`dition. Because the martensitic ‘wires have been plastically
`deformed to more than 30'}. however. they exhibit an un-
`usual springback and rubberlike character. After a 90° bend
`test.
`the coldworked NiTi wires will almost completei'.
`unbend.
`in contrast to similar stainless steel wires which
`remain bent at a 45° angle. Figure 18 shows the results or
`comparative bend tests. and Figure 19 shows how the NiTi
`arch wires are tied into malposed teeth.
`: It is claimed that using NiTi arch wires offers advantages.
`such as fewer arch wire changes during treatment. a greater
`tworking range land thus fewer arch wire adjustments). less
`patient discomfort. and shorter treatment time.
`Blood Clot Filters
`A" term ‘caL-a filter using a .\'iTi alloy has been evaluated
`by Dr. 3.11 Simon of the Harvard Medical School and other
`colleagues. The device they propose is a new method I'
`trappmg "wandering" blood clots. A chilled.
`initiaiij
`straight NiTi wire (martensitic conditionl assumes a com-
`plex filter‘shape as it warms to body temperature (parent
`phase conditionl after being placed into the term com (a
`large yein which returns blood to the heart) by a catheter
`inserted in a vein in the arm. A straight martensitic wire
`obtains a complex cross sectional shape once ejected from i
`the catheter into the warm body.
`a process schematically
`shown in Figure ‘20.
`
`i
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`HEAT ENGINE APPLICATION OF SME:
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`
`Figure 18. Bend tests comparing cold-
`worked stainless steel and cotdworked
`NiTi manensitlc alloy.
`(Courtesy G.F.
`Andreasen.)
`
`
`
`
`
`
`
`
`
`
`
`Figure 19. NiTi dental arch wire before (above) and attér (below) being tastene}! to malposed teeth. (Courtesy G.F. Andreasen.)
`
`nus:
`@ HIGH TEMP
`
`com
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`Figure 20. Schematic at vena cava tilter
`operation. (Courtesy M. Simon.)
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`Figure 21. Radiograph showing placement of vena cava filter
`in a dog. (Courtesy M. Simon.)
`
`
`
`Figure 22. Composite aneurism clip: a.) of Ag; b.) at NiTi.
`(Courtesy T. Honma.)
`
`Figure 23. Prototype artificial heart using
`NiTi
`contractile
`elements.
`(Courtesy
`P.N. Sawyer.)
`
`
`
`
`
`Such defies can prevent 905- oi Ciots iormeo in the legs.
`pelvis, or thighs. and which later dislooce. irom reaching thr—
`neart
`lung region and caustns a pulmonary embolism. Tht
`NiTi Iilter oti'ers several advantages. such as avaidinc anti-
`coaeuiant drugs idaiieerous when internal bleeding may
`UCCurl and surgery.
`rioth risky procedures. and requuing
`only a local anesthetic. Such devices promise greater saiety.
`simplicm. and speed oi
`introduction.
`Experiments on noes have been \‘en‘ encouraging and those
`involving humans are anticrpatcd Soon. Figure £1. a radio-
`graph [TI on .\'iTi
`i'ilter implanted into the ratio t‘aL'u oi
`a
`ting. clearly snows the trapped emiiolus :it one side of the
`lilter.
`
`intracranial Aneurism Clips
`Aneurism clips or clamps used to tie off unwanted bulge:
`which iorm in arteries have to be easily applied and temot‘ied
`After experimenting With different verstons of metallic
`aneurism clips. Honma and colleagues in Japan reported on
`a basm silyer clip straddled by a supplementary clip made
`of NiTi. Such composue clips. as shown in Figure 221. met all
`mechanical conditions tor practical use and could be re.
`moved easily by local heating.
`Artificial Hearts
`Dr. Philip Sawyer and associates at the State University
`of New York conceived the intriguing idea of using NiTi
`SHE alloys to act as prosthetic muscles when heat poised.
`and they have proposed using .\'iTi wire strands as a con-
`tractile artificial muscle [or an artificial heart. They claim
`that N'Ti alloys are a potentially practical means of obtain
`ing prDleate contractility of the chamber wall and a satis-
`l'actory beginning towards developing an artificial muscle
`"skin-activated" cardiac chamber. The Wire strands were
`initially constructed using "muscle groups" Whlch were
`anchored to the exterior of the chamber in various configura-
`tions to att‘empt
`to replicate the contractility of the lelt
`heart ventricle.
`Such artificial hearts are envi5ioned to be activated b-
`electrical heating and programmed timing cycles involvin:
`various groups oi contractile elements. Using NiTi elements
`attached to an elastomer chamber. significant pumping
`speeds were obtained. Such devices have pumped water up
`d
`lfiil cm gradient 12—15 times per minute.
`Sawyer and colleagues suggest that the next critical step
`is an evaluation in L'IL'D iollowinsr the implantation of such
`devices in dogs and calves This is a novel. exciting posstv
`bility for applying an SME alloy. Figure '33 shows a prototype
`artificial heart with elastomer pumping elements activated
`.1-
`by bands of NiTi wires.
`Orthopedic Devices
`Workers at
`the Polytechnic Institute oi‘ New York isee
`(Tastleman et al.i have suggested the manufacture of bone
`plaIEs tram NiTi alloys tor the compression iixation of bone
`l'racturcs. A "preprogrammed" NiTi
`implant Would be
`lastened to'a fractured hone on each Side oi
`the fracture.
`Raismg the plate temperature locally some ill—15!” above
`body temperature would cause the shape memory to con-
`tract
`ihu plate and fit
`the ends oi
`the i'raetured bone
`securely ingei'nrir Such :1 process would iriroive a muci‘.
`simpler surcical procedure than is now common. ustnli'. 1”"
`.
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`illillflr
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`.i.-:..~'. nit iiziplant l'l‘lltlL'l'lfll it) surrotiiiii-
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`- i"‘.’i'JIIll‘.""i'f‘. oi hod\'or*."'1>
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`:: liliiiL‘l!Jl~; more iouiiti.
`leililll‘itl
`to the (StillCllln
`illili
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`illlIW'i lire suii'imutiiix L‘iit'nI‘luIIlJlt‘ iiitli on: tissue
`[IJ mirrniit
`iiii‘titct
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`:i
`liliiinrttcrml.
`-\titill1f:r eviiiudtiuti iii _\'iTi :iilm's tor orthopedic implant-
`was conducted li‘. Ur.
`-liil11l:‘.- Hughes iii
`the 'L'iiiyersui
`Mississippi Hi: also prepared liiiiie iiiutcs il-'icurc ill :1!‘
`lOL'R\»\L OF MET \L‘:
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`“up $33, Wag-J.-
`
`‘3
`
`confirmed the biologic ECCEpLabllltv' of NiTi alloys. Hughes
`3150 suggested a new type or hip prosthesis and intramedul-
`:er rod. Instead of cement to hold the stern of the prosthes‘is
`i: place. the metallic components Within the bone are firm-
`1
`fixed by the gripping segments of NiTi in the stern of the
`prosthesis.
`Another proposed orthopedic deVice involves usmg NiTi
`alloys in a Harrington rod for straightening a bent spinal
`column.
`
`SOME FURTHER APPLICATIONS
`
`A few additional applications of SME alloys can be briefly
`mentioned. A 13.5. patent has been obtained for a variety of
`intrauterine contraceptive deVices (IUDsl
`fabricated from
`.‘JiTi SME alloys. A Cu.Zn SME alloy has been proposed
`for manufacturing integrated circuit packages with SME
`used in making contacts. Finally, researchers at the Poly-
`technic Institute of New York have developed “blind plugs"
`of NiTi to be used as remotely activated, internally placed
`seals for old gas lines under streets in New York City.
`
`CLOSURE
`
`The previous discussion suggests that. from a metallurgi-
`cal point of view. shape-memory alloys are reasonably well
`understood. Some of the many existing and proposed appli-
`cations of this new class of materials have been described.
`and this admittedly nonexhaustive discussion indicates a
`remarkable variety of new things that can be done with
`these materials. Since the shape-memory effect is an intrin-
`SIC consequence of martensitic transformations.
`this type
`of phase change. once thought to be of interest only for
`quenched steels. takes on new dimension and importance.
`Many new developments and applications are expected now
`that the Biblical ”serpent” has been tamed.
`‘
`
`ACKNOWLEDGMENTS
`
`I would like to thank many friends and colleagues for
`providing information and photographs“ They are too num-
`erous to mention individually, but their contributions are
`identified in the text.
`I am particularly indebted to.Dr.
`Tsugio Tadaki
`for
`translating this report
`into Japanese:
`thanks are also due Dr. Morris Simon for providing the
`Biblical description of the shape-memory effect.
`I wish to
`acknowledge the support of the National Science Foundation
`the Materials Research Laboratory at
`the University of
`Illinois. and the Army Research Office.
`
`
`
`Figure 24. Radlograph showing bone plate made trom NITi
`alloy attached to a bone. (Courtesy James Hughes.)
`
`Based on Thermoelastir Martensitic Translormations and the Shape Memory Effect.‘
`Metallurgical Transactions. .A {1973 p.
`‘19
`Dental and Medical
`G F Andreasen and R.E.\1ormw."1.aboraturv and Clinical Analyse: of .‘citinol Wire.
`American Journal of Urihodantics. Til ll'l (1978) p 142.
`.\ Neuu. T lwabuchi and T Hnnma.‘ 'A Study of the TiNi lntracranial Aneuriam Clip
`HBVII’IZ the Shape Memory Effect." Bulletin of the Real-rah Institute of Mineral Dren-
`ing and Metallurgy. Tohoku University. Sendai. Japan. 3: i197!“ p. 6‘:
`M Simon. R. Kaplow. E Salaman and D Frriman. “A \ena Cave Filter Liam: Thermal
`Shape Memory Alloy." Radiology. 125 ill (19771 p 89.
`1’ .\' Sawyer rt 51.. "Further Study of Nitinol Wire as Contractile Anil'icul Muscle for an
`Artificial Hean." Bulletin of {he Tuna Heari Institute. :I IiSTGI p. 65.
`L.$. Castieman at al.. "Biocampatibiliiv of Nitinol Alloy as an Implant Matanal." Journal
`of Biomedical Materials Reacarch.
`[U “9761 p 695
`.l.L. Huzhes.”Evaluation of \itinui lDl' Lee a: a Material in the Construction of Ortho—
`paedic 1mp1anu”Finnl Report DAMD 17-N-C «1041 L5. Army Medical Fleuarcn Inn
`Development Command. Frederick. Maryland. 1977.
`MA. Stnmerling at al. '.-\ Proposed Medical Application of the Shape Memory Effect: A
`\'iTi Harrinirton; Rod tor the Traatmant oi' Scolioaisfi ' in Shapr Mrman‘ E/Ircts in Alloys
`1. Perkins. éd.. Plenum Press. \em \ork. 19-3. p. 563.
`Company Brochures
`Raycheiit Corporation. Mano Park. California. 94025. Coupluus. Clamps. Plugs. Elrcrncnl'
`( unnrrmrx
`.
`Delta Memory \letal Company. loswic'n Suffolk. 1P2 OEG. Enaiand. Manual on the De-
`“I” 0] Shape Mrmun E/[u'r Actuators
`L'nitak Corporation. Monmvm. California. 91016. Brochurr on .\'i'Ti' Dental Arrhwrres
`Foxbom Corporation Foxbom. Masaacnusetts. 02085. Technical
`lnrarmarion Sheets on
`.Viiinoi Pen Urn-e L nit
`
`
`
`ABOUT THE AUTHOR
`£-
`
`BIBLIOGRAPHY
`
`Metal
`
`General
`C M Wayman and K Shimizu. "The Shape Memory l'Marmein'i Effect In Alloya."
`Science Journal. 6 11972) p 173
`J Perkins. ed . Shane Mrmon Effects in Allow. Plenum Press. New \ork. 1975
`C M Jackson. H J Warner. and R J Wanilewalii. "55 Nitinol—The Alloy With a Memory:
`1L§ Phyaical Metallunry. Propertiea. and Applications." NASA Rzporl SP 5110 11972)
`L MCD Schetky. "Shape Memory Allova." Scientific American. 241 l19791 p 74
`D Goldauin.
`'A Source Manual for information on Nitinol and NiTi." Naval Surface
`ltl-eanona Center. Silver Spnnz. Maryland. Report NSWC/WOL TR 78-26 (1973)
`Fundamentals and Mechanisms
`L Delaey. RV Knahnan H Taa. andH Warlimonl‘'Therrnoelaaticiu Pseudoelasticiri:
`a-: the Mrmorv Effects Associated wiih Martensitic Transiormatioi’is
`Journal of Mn-
`tr.‘ials Science.‘11197-ll p
`1521. 13516 1545
`T
`iahuri and C M \‘v ayman Crvsuillorraphic Similantin in Shape Memon Marten
`"
`Aria Melallurzlcn " Q79i p 979
`we.
`
`
`
`\Hflun midi
`.‘tl V.rri-_
`.“r :r..-pc Memory Eifrt‘. in 11’. Ach Marin-mile Act:
`
`\it‘LallUlKli‘u .‘e ililwi g
`The Shape Memory Effect in 1:111
`.\rrino
`:ahuri. Li M \k avman 1 Tania and 5
`.ZnAi and l‘iiZiilin Marianna Act:
`.Virinllurxicu. J.‘ iiiwm n
`16
`r‘wrrnmm IL (M! \T 71 L'Illmflllnfiul Conlrrtnc: nn Martcnaitic Translormaiilina Alpine
`91% Boston Mass
`19:!)
`uslriril
`l mag-s Him l. 1) r.
`‘-'
`17.
`l we i'il Hrs: lizroverabm Liiuolim' 1'rciiiioloh in bnipvnrn
`i‘muclli)n
`\aval Lnairu-crs Journal. April 1979 i) 45
`l’om Manuiacture rii rn intrirrated Circuit Parkaar
`in shear .Hrmnn Efircts in
`1*
`A
`in:
`.1 Perkins ea
`Plenum Press. New york 1975 p 32.3
`anines
`.—- rrraimis .Virinol Hrar EMIHI (.onlrrrrirr heptemner £6 27
`r
`riace Lemar aiivrr :pnna. Maryland. NSWC TR 79-441
`1*
`‘ Tone and C M Wavman.
`'Thrrmodvnamii: Conaioerationa of Solid Slate Engines
`
`
`
`C.M. Wayman received a PhD in metaliurgy
`from Lehigh UniverSIty in 1957; he then
`iomed the Universuy of ”Mom where he has
`been Professor of Metallurgy Since 1964. An
`acknowledged expert in the