`
`KIRK-OTHMER
`
`ENCYCLOPEDIA OF
`CHEMICAL TECHNOLOGY
`
`THIRD EDITION
`
`VOLUME
`
`20
`
`v—
`
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`.:
`I E _;r_n F-Lent CW:3
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`
`REFRACTORIES
`TO
`SILK
`
`‘EARV
`
`1807
`
`1982
`
`no
`
`é...
`I'LISHV
`
`A WILEY-INTERSCIENCE PUBLICATION
`
`John Wiley & Sons
`NEW YORK -
`CHICHESTER -
`
`BRISBANE
`
`. TORONTO .
`
`SINGAPORE
`
`Lombard Exhibit 1003, p. 1
`
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`
`3R
`
`TH
`
`Lombard Exhibit 1003, p. 1
`
`

`

`
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`7-25
`
`SEPARATION SYSTEMS SYNTHESIS
`
`A. W. Watcher: and G. Suphmopoulm. “Studies in Process Synthesis—L" Chem. Eng. Sci. 30. 963
`(1975).
`
`J. D. SEADER
`
`University of Utah
`
`SHALE OlL See Oil shale.
`
`SHAPE-MEMORY ALLOYS
`
`The shape-memory effect is based on the continuous appearance and disap-
`pearance of martensite with falling and rising temperatures. This thermoelastic be-
`havior is the result of transformation from a phase stable at elevated temperature to
`the martensite phase. A specimen in the martensite condition may be deformed in
`what appears to be a plastic manner but is actually deforming as a result of the growth
`and shrinkage of self-accommodating martensite plates. When the specimen is heated
`to the temperature of the parent phase. a complete recovery of the deformation takes
`place. Complete recovery in this process is limited by the fact that strain must not
`exceed a critical value which ranges from 34% for copper memory-effect alloys to 6—8%
`for the Ni—Ti system. A number of other characteristics associated with shag memory
`are 5291929523; pflioelasticitv or superelasticitv, two-way shape-memory effect.
`martensite-to-martensite transformations, and rubberlike behavior.
`
`Martensite is a metastable phase that forms when a phase stable at elevated
`temperature. such as austenite in steel. is cooled at a certain rate. thereby suppressing
`the formation of phases that are diffusion-controlled (see Steel). A characteristic of
`martensite is the relationship between the parent-phase crystal and the martensite.
`For steel, the austenitic phase is fcc. When it transforms to martensite, the orderly
`shift to a bct (body-centered tetragonal) structure takes place (see Fig. 1). The
`structure stable at elevated temperature varies with the alloy system, and the mart-
`ensite varies from a simple bcc to a more complex structure which may have as many
`as 18 atom layers to define the unit cell.
`
`
`
`i'i-i'-l|
`llhll|will
`
`
`
`
`
`
`
`
`
`
`
`Figure I. The original fcc structure (0) changes to the bet with (111) 7 I 010) a and the [110]
`7 ii [111] a.
`
`NV‘B.‘
`
`Lombard Exhibit 1003, p. 2
`
`
`
`Lombard Exhibit 1003, p. 2
`
`

`

`
`
`Memory 4:
`effect.
`
`eVuLEd
`:essing
`istic of
`
`ensite.
`irderly
`
`..
`
`mart-
`
`many
`
`Vol. 20
`
`SHAPE-MEMORY ALLOYS
`
`727
`
`The temperature at which martensite starts to form on cooling is referred to as
`the M, ahd the temperature at which the elevated temperature phase has been com-
`pletely transformed is the M/. On heating a martensitic specimen, the temperature
`at which the reaction reverses to the elevated temperature phase is designated A,; the
`reaction is completed at a higher temperature designated A, (see Fig. 2).
`Thermoelastic behavior was first discussed in 1938 in a study of a Cu—Zn alloy
`which showed that martensite could be made to appear and disappear with a change
`in temperature (1). In a later study in the USSR, the phase relationships in'brass be-
`tween the high temperature 5 phase and martensite were examined (2). The length
`changes that occur on martensite transformations under load in the Fe-Ni system
`were determined (3). A later investigation of the shape-memory effect in Au—Cd alloys
`demonstrated that useful force could be generated in this type of transformation. These
`findings led to research on the practical applications for the shape-memory effect,
`and investigation of the martensite transformation kinetics in the Ni—Ti system (4).
`This system is commonly referred to as Nitinol (Nickel—Titanium Naval Ordnance
`Laboratory). The essential features of the martensite transformation are common
`to all alloy systems exhibiting the memory effect. whether they be 2H. 3R. 9R, or 18R
`structures (5-6). in some alloy systems, the various martensites are both internally
`faulted or internally twinned and may possess different crystal structure. However,
`in all cases studied to date. an initial parent phase transforms to self~accommodating
`martensite plates that are characterized by six plate groups. each consisting of four
`variants. Because of the self-accommodating character of the transformation, the
`average shape deformation in a particular plate group is effectively zero.
`Table 1 lists the martensite alloy systems that have been investigated with respect
`to thermoelasticity. pseudoelasticity, shape-memory effect. and two-way shape-
`memory effect. The bcc (3) phase is the dominant parent because of the comparatively
`large thermodynamic difference between the martensite transformation from a bee
`parent to SR, 2H. 18R, or SR. and from an fcc parent to bee or bar. The former is typical
`for nonferrous alloys. whereas the latter accounts for the hardening of steel.
`For an excellent general review of martensite kinetics. microstructure, and
`thermodynamics as they relate to shape memory. see ref. 7 and the First International
`Conference on Shape Memory (8).
`
`
`
`Temper-run.———>—
`
`I l
`
`I I I l l I l I I I I II
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`
`Figure 2. Martensite phases as a function of temperature. A, - reverse reaction is finished: A. '
`reverse reaction starts: M, - martensxte starts to form; and M, I martensite is completely transformed.
`
`Lombard Exhibit 1003, p. 3
`
`,--..
`
`Lombard Exhibit 1003, p. 3
`
`

`

`ramWon . .-_~“.4. ~rxvrrL-z. e“-..
`
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`
`7'28
`
`SHAPEoMEMORY ALLOYS
`
`Table 1. Alan Exhibiting Mart _'ic£«ecu
`
`Thermoeluu‘c
`
`Shape memory
`
`Two-way shape memory
`
`Cu-Al
`Cu—Zn-Al
`ln-Tl
`Ti—Ni
`
`Ag-Cd
`Au—Cu-Zn
`Cu-Al—Ni
`Cu—Zn
`Cu-Zn‘
`Fe-Pt
`Ti-Ni
`
`
`
`Az-Cd
`Au—Cd
`Au—Cu-Zn
`Cu—Al
`Cu-Al-Ni
`Cu—Zn
`Cu-Zn-Al
`Cu-Zn~G|
`Cu-Zn-Si
`Cu-Zn—Sn
`Fe—Pt
`FeoNi
`ln-—Cd
`ln-Tl
`NioAl
`Ni—Ti
`304 stainless steel
`Ti—Nb
`Ti-Ni
`
`
`
`
`......-—-....—._._..
`
`' With ternary additions of Ni. Ag. Au. Cd. ln. Ga. Si. Ge. Sn. and Sb.
`
`The behavior of shape-memory-effect (SME) alloys is exactly opposite to that
`of normal metals in the following essential feature: as the temperature rises above A,
`and martensite is increasingly converted to the 6 phase, the modulus of elasticity in-
`creases. This change is spectacular for Cu-Al-Zn SME alloys where the Young’s
`modulus changes by a factor of 50 from 0.4 GPa (58,000 psi) at the A. to 20.7 GPa (3
`X 105 psi) near the A]. Obviously. a spring tension or torsion device develops a greater
`force with increasing temperature and this force can be either static or it can be used
`to produce a controlled motion. The force that can be developed by an SME device
`is as much as 200 times the force that could be developed by a bimetallic element of
`the same size or volume.
`
`The Crystallographic Nature of Shape Memory
`
`The martensitic memory or marmem effect occurs in alloys where both the parent
`and the martensite are ordered and exhibit crystallographically reversible, thermo~
`elastic martensite transformations (7.9—1.0).
`It has been demonstrated in one of the simplest systems, Cu—Zn. that a single
`orientation of the bcc 6 phase transforms on cooling below the M/ to self-accommo-
`dating variants of martensite. The habit planes for the transformation are symmet-
`rically disposed around the (110) family of planes, of which there are six in the cubic
`system. Habit planes are the planes in the parent phase from which transformation
`takes place. Thus, for the plane (011) the four variants are (2 11 12). (2 1211).(§12 11).
`and (i ll 12); this set is termed a plate group. The six (110) planes offer a total of 24
`martensite variants. When the martensite group is deformed. deformation proceeds
`by a gradual conversion of four variants to a single martensite plate rather than by
`grain-boundary sliding or slip. The surviving orientation depends on whether the strain
`
`Lombard Exhibit 1003, p. 4
`
`--vh\-T‘
`
`.Vu
`
`emu-MuI'
`
`
`
`Lombard Exhibit 1003, p. 4
`
`

`

`
`
`Vol. 20
`
`SHAPE-MEMORY ALLOYS I
`
`729
`
`is tensile or compressive and whether the growth or shrinkage is such as to minimize
`strain-energy accumulation. Upon heating, the reverse transformation from martensite
`to the 6 phase occurs between A, and A; and the single crystal (plate) of martensite
`transforms to a single 6 crystal with the original orientation of the parent phase. In
`the case of Cu—Zn and other systems with relatively complex ordered martensite
`structures (9R or 18R), the reverse transformation is crystallographically restricted.
`Thus, although there are many variants that can develop on transformation from
`parent to martensite, only a single-parent orientation is possible in the reverse, or
`shape-recovery. transformation.
`When a martensite group is deformed to coalesce into a single orientation, the
`dominant mechanism is twinning. Each twin is actually an alternative variant of the
`martensite crystal. Thus. for the four variants that cluster about the (110) habit, each
`orientation is a twin of another, and by this degenerate varianbtwin relationship. a
`group of martensite plates formed from a single parent crystal can, on deformation,
`coalesce to a single crystal (single variant) of martensite.
`The parent phase is usually ordered 82 or DC; symmetry, although initially a
`transformation can take place from disordered to an ordered or superlattice structure.
`This ordered structure transforms to one of the four martensite crystal forms 2H. 3H.
`SR, or 18R that exhibit shape memory. These designations refer to the sequence of
`stacking of planes to form the ordered structure. A sequence could be obab, nbcnbc
`or abcbcacab or similar variations. The repetition of these planes to define a unit cell
`is then 2. 3, and 9. respectively.
`Typical alloys that transform to these various martensites are
`
`2H, Cu—Al—Ni and Ag—Cd
`3R,'Ni—Al
`9R, Cu-Zn
`18R, Cu—Zn—Al.
`
`A distinction exists in the habit and defamation characteristics of the 2H and
`
`SR types and the 9B. and 18R martensites. The former are internally twinned and
`deformation occurs by a detwinning of a variant plate. The latter are internally faulted
`and deformation proceeds by variant—to-variant coalescence followed by group-to-
`group coalescence. Although these structural differences exist. the self-accommodating
`habit-plane grouping with respect to an (01 1) plane is common to all systems exhibiting
`the marmem effect. The 93. martensite is derived from a 8-; parent, whereas the 18R
`transforms from a D03 superlattice. The difference in the stacking of (110) planes is
`because of the requirement for an invariant plane strain that involves a restricted
`stacking of close-packed planes. In order to obtain the required invariant plane-strain
`condition, both the SR and 18R martensite contain stacking faults to provide the
`necessary accommodation. The sequence of B to 62 to orthorhombic GB. for a Cu—Zn
`alloy is shown in Figure 1.
`As noted previously, the atoms in each plane are displaced relative to those above
`and below and from a repetitive sequence of a nine-plane group. These complex atomic
`displacements take place by a combined process of shuffling and shear to arrive at the
`9R structure. The 3R martensite twin plane is identical to the SR and 18R fault plane.
`in the case of 2H martensites, no such twin-fault correspondence exists, and the twin
`is derived from a different parent (110) plane.
`When sufficient strain takes place during defamation of a martensitic structure.
`
`
`
`Lombard Exhibit 1003, p. 5
`
`
`
`Lombard Exhibit 1003, p. 5
`
`

`

`
`
`I C
`
`L-
`
`730
`
`SHAPE-MEMORY ALLOYS
`
`six plate groups coalesce to a single orientation where the surviving variant from the
`original 24 allows the greatest extension in strain direction. This process varies with
`the nature of the strain. tensile. compression. or bending properties (Fig. 2). Once a
`group becomes a single variant. it can change its orientation to that of an adjacent
`group by twinning.
`Although some of the crystallographic details differ for different memory-alloy
`systems. the essential processes described above are common. Some systems such as
`Ni-Ti (Nitinol) and Cu—Zn-Al have premartensite transformations with ordering.
`but in the final analysis the sequence of 13 to martensite cluster to single-variant
`martensite to 6 parent is the same. Schematically, the memory effect is summarized
`in Figure 3. A stress-strain. temperature-strain diagram is shown in Figure 4. Assuming
`an initial martensite structure. as stress increases a point A is reached where the
`martensite starts to coalesce to form a single variant. When the stress is released at
`B. a residual strain 4: is left. As the temperature is raised. transformation of the mar-
`tensite starts at A, and continues with increasing temperature to A; at which point
`all the strain is recovered.
`
`Simple shape-memory behavior can be extended to two-way memory. In order
`to exhibit two-way memory where the part spontaneously changes from one shape
`to another on cooling or heating, a conditioning of the martensite must take place. This
`
`.41
`
`Heat in
`
`above
`
`I
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`
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`
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`
`P—Lr—fi'ii
`
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`
`Illustration of the shape-memory effect. Lo I original length. For other definitions. see
`
`Figure 3.
`Figure 2.
`
`
`
`Lombard Exhibit 1003, p. 6
`
`

`

`
`
`Vol. 20
`
`SHAPE-MEMORY ALLOYS
`
`- 731
`
`.n
`
`. 3n=
`
`In
`
`Srram,m/rn
`
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`
`Figure 4. Stress-strain curve demonstrating the shape-memory effect. c - raidual strain.
`
`conditioning is brought about by limiting the number of martensite variants that form
`upon cooling through the applications of an external stress during transformation.
`The stress favors the initial formation of selected variants. similar to the fact that
`
`stressing a martensite group causes the selective growth and shrinkage of suitably
`oriented plates. This limit imposed upon the number of variants formed reduces the
`self-accommodating feature of the usual transformation and increasa the residual
`stress. By repeating the process a number of times, the restricted variant group and
`its associated internal 5:recs spontaneously revert to (3 on heating and then to a singular
`martensite group on Cooling.
`Owing to the fact that the internal boundaries of martensite—martensite groups
`are relatively mobile, a cyclic stress causes a back- and- forth motion of these boundaries
`which produces a high internal friction. This behavior is the basis for using shape-
`memory alloys as vibration-damping materials.
`The other property peculiar to marmem alloys is the ability under certain con~
`ditioris to exhibit sugrelastic behgn'gr, Although in one sense. the 3—870 apparently
`recoverable strain of the memory effect is truly an extended or pseudoelastic behavior.
`an even further elastic range is possible. When many of the martensitic alloys are de-
`formed well beyond the point of the initial single-coalesced martensite stage, a
`stress-induced martensite—martensite transformation can occur. In this mode of de-
`
`Nr}~,>1,y;',.,.....
`
`m
`
`formation strain is reversible through stress release and not by a temperature-induced
`phase change, and recoverable strains as high as 17% have been observed.
`In the shape-memory process, the temperature is controlled at which the effect
`takes place. The alloy composition determines the working temperature range of a
`device. whether one-way or two-way. ln the case of Nitinol. the composition is usually
`ca 5&50. The M, is extremely sensitive to variations in the Ni-Ti ratio. This sensitivity
`is reduced by the addition of copper to the Ni—Ti binary system. The other alloy system
`that has been exploited for a very broad range of applicationsis the Cu-Zn—Al ternary.
`The M, of this alloy can be varied from 170°to —105°C although a range of -lOO°
`to 60°C is more acceptable for long-term stability. This range ofM. temperature ran:
`Lombard Exhibit 1003, p. 7
`
`Lombard Exhibit 1003, p. 7
`
`

`

`
`
`
`
`SHAPE~M£MORY ALLOYS
`
`within the ternary field of CU—(13-27‘70) Zn—(4.5—9%)—AL Additions ofSn. Mn. Si. and
`Ni to this ternary system have been investigated for special devices.
`
`Economic Aspects
`
`For a period, the United States Naval Surface Weapons Center was the sole
`supplier of Nitinol. usually as small-diameter wire; the supply was limited to a few
`compositions.
`,
`In 1981, Nitinol Devices (11) offered 0.457~mm wire with a zero-force transition
`
`temperature of 38°C for $1.95/m or $1760/kg.
`The Raychem Corp. (12) produces Nitinol. but selb it only in the form of finished
`devices. This company also produces SME brass under the trade name of Betalloy,
`sold only as a finished actuator.
`The price of SME brass. typically the Cu—Zn—Al family of alloys. is not published
`since it is sold only as a finished and heat-treated device. A typical small spring sells
`in the range of $0504.50.
`.
`At this time, only Delta Memorial Metal Ltd. (13). UK, and Proteus Metal (14).
`Brussels. Belgium. manufacture SME brass actuators. Both companies market fin-
`ished. heat-treated components ready for installation.
`
` 732
`
`Applications
`
`The first shape-memory alloy to be placed in commercial use was Nitinol em~
`ployed as a high reliability coupling. In this device. known as a Cryofit connector (12),
`a small tubular piece is machined to an initial inside diameter ca 4% smaller than the
`outside diameter of the tube to be joined. The tube is heated to the 15 phase at elevated
`temperature and quenched to yield martensite. It is then expanded to a diameter
`sufficient to allow it to fit over the tubes to be joined, usually ca 4%. Upon heating,
`the ca 8% strain is recovered. producing a very high compressive~force joint of superior
`reliability. An M, of ca -120°C was chosen because these connectors were first used
`for aircraft hydraulic couplings which experience a service temperature range from
`-100°C to perhaps 45°C. This application was so successful that it was extended to
`the coupling of piping systems on ships where the pipe diameter ranged from 1.9—5
`cm (see Piping systems). in spite of the high cost of Nitinol for both alloy shapes and
`components, the labor savings over other joining systems. particularly welding (qv),
`has made the process economically attractive. The fact that once expanded to the open
`position the coupling must be stored at cryogenic temperature has not prevented their
`use for undersea oil-line connections. Undersea pipes are usually joined by welding
`in a hyperbaric chamber. a difficult and costly operation. Using Cryofit units. pipes
`up to 15 cm dia have been joined at depths of >100 111.
`Another use for the Ni-Ti memory alloys is in high reliability strip-chart pen-
`recorder drives (15). The usual D'Arsonval movement was replaced with a Nitinol wire
`which, when it expanded or contracted. moved the recording pen through a system
`of simple pivots. The wire is heated by a high frequency induction heater whose fre-
`quency, and therefore heat-coupling efficiency, is proportional to the input signal.
`Since this is a two-way memory effect, such wire must go through a training period
`to develop a repeatable shape recovery. These highly reliable and shock resistant re-
`corders have been very successful.
`
`Lombard Exhibit 1003, p. 8
`
`Lombard Exhibit 1003, p. 8
`
`

`

`
`
`Vol. 20
`
`SHAPE-MEMORY ALLOYS
`
`733
`
`Medical Applications. The alloy N itinol resulted from a successful research
`program intended to create a high strength metal resistant to corrosion by seawater.
`With these properties, it is not surprising that it has interesting applications in memory
`devices for medical implants requiring passive chemical behavior (16) (see Prosthetic
`and biomedical devices).
`-
`
`An earlv medical device exploits the su erelastic behavior of Nitinol rather than
`its memory effect. This device. the restraining wire arch in an orthodontic brace at-
`tached to teeth being straightened, provides a constant force which produces the de-
`sired-effect more quickly than conventional braces. The wire is deformed in a man-
`ensive condition to a point where martensite-martensite reaction occurs. Because of
`their wide elastic range, these wires are superior to the usual stainless-steel wires, which
`because of stress relaxation, require constant readjustment.
`Exploiting the true memory effect has been the aim of a medical research team
`specializing in cardiovascular problems (see Blood, coagulants and anticoagulants:
`Cardiovascular agents). Addressing the prevention of blood clots, a group at Beth Israel
`Hospital in Boston has successfully demonstrated on animals a system for screening
`blood clots large enough to be hazardous (17). A N itinol wire bundle in the martensitic
`state with a composition selected to give an A, slightly above body temperature.isis
`
`deformed into an umbrella- like screen. The screen is collapsed into a straightstrand
`of wires and inserted by means of a catheterintowthe vena cava where, upon warming,
`it opens to form a clOt screen.This device may offer an effective method to guard
`against the aftereffects of operations on legs or lower trunk or in cases of phlebitis where
`clots are a common occurrence. This system avoids complicated and sometimes high
`risk surgery and the side-effect problems associated with anticoagulant drugs.
`In the area of orthopedic surgery. Nitinol applications have been highly successful.
`Their range is as diverse as bone-fracture fixation, hip implants, and the reduction
`of bone deformaties and structural abnormalities such as scoliosis.
`
`A most common orthopedic problem is the accurate fixation of fractures. par-
`ticularly multiple breaks common in sports. Screws and plates are generally employed
`but the alignment is not always exact and the fracture interfaces are not always in close
`contact. With a shape-memory plate that shrinks on heating, a fracture can be aligned
`by screwing the plate to bridge the fracture and, when it is warmed by body heat or
`artificially heated by diathermy, the contractions pull the surface: intoWet
`ensuring rapid calcification and healing. Devices of this type are under investigation
`in the FRG (18). as well as in the U.S. and the UK.
`
`Although hip replacements are now a common procedure, they still present
`problems of fixing the new ball joint rigidly in the femur. A long spike is usually driven
`into the hollow of the bone and cemented with acrylic or similar organic adhesive. The
`occurrence of hairline fractures is common. and misalignment may require a second
`operation. A new device employs a beta-conditioned hollow tube which is split
`lengthwise and bent to the shape of a C. After quenching to martensite, it is closed.
`Upon insertion, the tube is warmed by the Wand expands to the original C
`configuration, providing a tight fit, which, since the grip is along the entire length,
`minimizes the chance of fracture. The ball joint is then attached.
`Scoliosis, a lateral curving of the spine, is a disfiguring and disabling ailment. The
`cure is long and difficult and requires the repeated and gradual straightening of a
`Harrington rod to force the spine into alignment. These rods have been replaced by
`a memory alloy which, when initially attached to the spine. has a matching curvature.
`
`Lombard Exhibit 1003, p. 9
`
`Lombard Exhibit 1003, p. 9
`
`

`

`controlled release).
`
`
`
`
`
`
`734
`SHAPE-MEMORY ALLOYS
`
`When heated externally, the rod attempts to straighten, applying a constant controlled
`force that gradually brings the spine into normal alignment. (19).
`Active exploration of memory-effect devices is underway for application in au-
`tomatic drug dispensing, an artificial heart muscle. prosthetic devices for arthritic
`joints, and systems to generate artificial peristalsis action (see Pharmaceuticals,
`'“m-filnom
`Mechanical Devices. As the Ni-Ti alloys have dominated the biomedical field.
`. so have the Cu—Zn—Al family of alloys taken a commanding lead in the field of ther-
`mally actuated mechanical devices. These include cu-cuxt breakers and electric relayS,
`thermostatic valves. window openers, climate-control devices for buildings and cars,
`safety devices. aerospace-antenna systems, and various fastener and connector de-
`Vices.Since the Cu-Zn-Al alloys are readily hot-worked, they have been generally used
`in the form of extruded wire. Springs in torsion. tension. or compression have been
`developed as well as tubes and rods in torsion. Flat strip or sheet can also be produced
`although not as readily because the cold workability of these alloys is limited.
`The automobile industry was among the first to develop SME actuators. An au-
`tomobile contains ca 25 devices which could exploit SME, including thermostatic fluid
`and air controls, air-conditioner valves, exhaust emission controls, carburetor valves
`and automotive fans. Such devices are now in the development stage in many
`countries.An interesting application now in road tests is an automotive-engine fan whose
`speed is proportional to the cooling demand. An SME spring controls the relative slip
`by this system. Exhaust-emission control is a worldwide concern and although Various
`catalytic devices provide a reasonably effective reduction in toxic emission. climate
`changes. particularly temperature, reduce their efficiency because of a shift in the
`fuel—air mixture. A carburetor jet with an SME alloy orifice that changes diameter
`in response to fuel temperature maintains a constantmixture and, as a result. stabilizes
`the exhaust chemistry (see Exhaust control. automotive).
`A concept to use the car-passenger heater as part of the engine cooling system
`allows a reduction in the size of the main engine radiator. When the heat generated
`by the interior heater is not needed. louvers controlled by SME devices conduct the
`In the area of home-climate installation, SME valves controlling water circulation
`in hydronic heating systems offer the advantage of simplicity and economy over the
`conventional combination of electric thermostat. relay. and electrically operated valves
`(see Air conditioning). An SME valve can be placed in each room to give individual
`walls, require the opening and closing of shutters to control the insulation. The Shim
`actuators developed for the control of crreenhouse windows offer reliable. automatic.
`and powerful operation (see Solar energy).
`A broad variety of thermal-overload devices are candidates for SME actuation.
`ranging from small relay systems to large circuit breakers. Protection against thermal
`overload is required on industrial electrical machinery to improve their fail-safe op-
`eration. For example. SME spring elements. because oftheir high force and small size,
`are incorporated in these devices. in addition. copper-based SME alloys are used as
`
`heat to the outside.
`
`wwh'rwwlwtawew-
`
`
`
`Lombard Exhibit 1003, p. 10
`
`Lombard Exhibit 1003, p. 10
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`Vol. 20
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`SHAPE-MEMORY movs
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`735'
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`couplings for specialized tube connections, eg, the connection between 'copper and
`aluminum tube ends used in air-conditioning systems. The SME couple has a polymer
`inner liner that acts as a sealant as well as a barrier to possible galvanic corrosion
`(12).
`
`As new forms of energy generation are needed, solar collectors, both passive and
`active, have been developed and the sun-induced temperature difference between the
`ocean surface waters and the ocean depths offers a particularly intriguing possibility.
`Shape-memory engines offer the potential of capturing this vast source of low tem-
`perature energy. No matter what the system. the scale would be enormous: however.
`active support is being given to such low temperature energy converters where the
`source is ocean thermal difference, thermoclines in high hydroelectric power-darn lakes,
`and effluents from conventional fossil and nuclear-fuel generator plants (20).
`Theoretical studies of shape-memory engines (2!) have compared the thermal
`efficiency of a shape~memory device operating as solid-state engine or solid-state
`heat-pumping device with more conventional Carnot fluid systems. The first SME
`engine demonstrating a useful power output with a modest temperature differ-
`ence was a rotary engine in which Nitinol elements operated in a bending mode
`and provided the motive force as they dipped alternately in hot and cold water (22).
`Although relatively inefficient, it showed the possibilities inherent in solid-state
`engines.
`‘
`In order to calculate the efficiency of a solid-state SME engine. a temperature-
`entropy diagram can be constructed similar to a Carnot cycle. The Gibbs free-energy
`change in the transformation of martensite to the parent phase is the driving force
`for such a system. Because of the hysteresis in the memory-effect transformation. the
`efficiency of a solid-state engine is always below that of a Carnot cycle. The sensible
`heat involved in the cycle, as compared with the latent heat of transformation must.
`for optimum efficiency, be kept low. This restriction is more difficult to achieve in a
`solid-state engine than in a fluid engine. Estimates of the efficiency of these engines
`range from 3-5%. These calculations are difficult bemuse of the problem of accurately
`estimating entropy and free energy change for the martensite—parent and parent-
`martensite under stress.
`
`Model engines built to date indicate that a solid-state engine can yield an effi-
`ciency at low temperature differences that is about equal to a gas- or fluid-phase engine
`and also offer a considerable advantage in size.
`Another possible application for SME materials is the storage of large quantities
`of thermal energy by cycling between M, and A,. In effect, in heating from M/ to A,
`the energy stored is the latent heat of transformation TAS plus the specific heat Cp.
`When thespecimen is cooled from A; to Mf. this energy is released. Since the tem-
`perature difference can, for a selected alloy, be on the order of 20°C. a large amount
`of energy can be stored in a relatively small volume.
`A final area of interest in SME motors is in solar-driven irrigation pumps for use
`in underdeveloped countries. Efficiency is not as important as the ability to pump
`water at modest rates from modest depths with no fuel requirement and at a low capital
`cost. Several excellent designs have been demonstrated under a United Nations De-
`velopment Program. Assuming 6 h of pumping per day and a peak pumping capacity
`twice the average. the required capacity is 5-10 L/s from a depth of 5 m. This corre-
`sponds to an average pumping power of 125—250 W/hm2 of irrigated land (23).
`
`
`
`
`
`Lombard Exhibit 1003, p. 11
`
`Lombard Exhibit 1003, p. 11
`
`

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`Hnwew~~
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`736
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`StkaEJMifiACJRY'ALLC)YS
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`BIBUOCRAPH'Y
`
`A. B. Greninger and V. G. Mooradian. Trans. Metall. Soc. AIME 128. 337 (1938).
`G. V. Kurdyumov and L. G. Khandros. Dohl. Akad. Nauk 535R 66. 211 (1949).
`E. Scheil. Z. Anorg. Allg. Chem. 207. 21 (1932).
`W. J. Buehler. J. V. Gilfrich. and R. C. Wiley. J. Appl. Phys. 34. 1475 (1963).
`R. J. Wasilewski. Metall. Tram. Z. 2973 (1971).
`A. Nagasawa. J. Phys. Soc. Jpn. 31. 136 (1971).
`L. Delaey. R V. Krishman. H. Tas. and H. Warlimont. J. Mater. 9. 1521 (1974).
`J. Perkins. ed.. Proceedings of the First International Conference on Shape Memory. Plenum Press.
`Toronto. Canada. 1975.
`'1'. A. Shroeder. I. Comelis. and C. M. Wayman. Meta“. Tram. 7A. 535 (1976).
`T. A. Shroeder and C. M. Wayman. Acta Metail. 25. 1375 (1977).
`Nitinol Devices. Escondido. Calif.
`Raychem Corporation. Menlo Park. Calif.
`Delta Memorial Metal Ltd.. Ipswich. UK.
`Proteus Metal. Brussella. Belgium.
`Foxboro Instrument Company. Foxboro. Mass.
`L. S. Castleman. S. M. Motzkin. F. P. Alicandri. V. 1... Ben-wit. and A. A. Johnson. J. Biomed. Mater.
`Res. 10. 695 (1976.
`H. C. Ling and R. Kaplan. Mater. Sci. Eng. 48, 241 (1981).
`G. Benarnann. F. Baumgart. and J. Hartwig. Metall (Berlin) 35. 312 (1981).
`F. Baumgart. G. Bensmann. J. Haasters. J. Nolker. and K. F. Schlegal. Arch. Orthop. Traumatic Surg.
`91. 67 (1978).
`W. S. Ginell. J. L. McNichols. and J. S. Cory. ASME Publ. 78-ENA-7 (1978).
`L. Delaey and G. Delepeleire. Scr. Metali. 10. 959 (1976).
`R. Banks. P. Hernandez. and D. Norgren. Report NSF/RANN/SE/AG-550/FR72/2 (UCID 3739).
`National Science Foundation. Washington. D.C.. July 1975.
`Testing and Demonstration of Small-Scale Solar-Powered Pumping Stations. Project CLONE/004.
`United Nations Development Program. Washington. D.C.. Dec. 1979.
`
`F
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`10.
`11.
`1")a.
`13.
`it
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`16.
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`17.
`18.
`19.
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`20.
`2