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	Shape Memory Alloys
		Shape memory alloys (SMAs) are metals that "remember" their original shapes.
		SMAs are useful for such things as actuators which are materials that "change shape, stiffness, position, natural frequency, and other mechanical characteristics in response to temperature or electromagnetic fields" (Rogers, 155).
		To fix the "parent shape" (as it is called), the metal must be held in position and heated to about 500 ° C. The high temperature "causes the atoms to arrange themselves into the most compact and regular pattern possible" resulting in a rigid cubic arrangement known as the austenite phase (Kauffman and Mayo, 5-6).
	www.stanford.edu /~richlin1/sma/sma.html (1432 words)

	Brainboost - what is a memory alloy (Site not responding. Last check: 2007-10-12)
		Shape memory alloy A shape memory alloy is a material that changes size, shape or character with the application of heat, electricity, a magnetic field or physical stress..
		A p Temperature: The temperature at which a shape memory alloy is about 50% transformed to Austenite upon heating, as measured by the peak on a DSC curve.M p Temperature: The temperature at which a shape memory alloy is about 50% transformed to Martensite upon cooling, as measured by the peak on a DSC curve..
		The mechanism of superelasticity behavior of the shape memory alloy is due to the reversible phase transformation of austenite and martensite..
	www.brainboost.com /search.asp?Q=what+is+a+memory+alloy&lfmq=1 (1673 words)

	Reducing power to a shape memory alloy background patent invention
		For one embodiment, the change in shape is characterized by a decrease in length L and an increase in the cross-sectional area A of shape memory alloy actuator 130, as shown in FIG.
		That is, where the slope of the curve of the resistance of shape memory alloy actuator 130 versus the temperature of shape memory alloy actuator 130 transitions from positive to negative.
		Note that the power supplied to shape memory alloy actuator 130, and thus the amount of heat, is increased to change from phase I to phase II and to activate shape memory alloy actuator 130.
	www.freshpatents.com /Reducing-power-to-a-shape-memory-alloy-background-dt20060727ptan20060162332.php (1748 words)

	Shape memory orthodontic archwire having variable recovery stresses - Patent 5683245
		Although the described archwires exhibit shape memory and exert different force levels on orthodontic brackets, depending upon the temperature of the archwire relative to the austenitic transformation temperature of the alloy, the force exerted at any given temperature is substantially the same throughout all regions of the archwire.
		The archwire is comprised of a shape memory alloy having a preset shape for exerting forces on teeth during orthodontic treatment.
		The orthodontic archwires of the invention are made by selecting a shape memory alloy having a suitable composition to achieve the desired properties of the archwire, and forming that alloy into a preselected arch shape adapted to exert forces on teeth during orthodontic treatment.
	www.freepatentsonline.com /5683245.html (3574 words)

	Shape memory alloy actuators and control methods - Patent 6574958
		SMA wires are wires of shape memory alloy that are treated such that they can be easily stretched along their longitudinal axis while in the martensite phase, thus re-arranging their atomic crystalline structure.
		A "stroke multiplying" SMA actuator is an SMA actuator in which the stroke of the actuator is greater than the contraction or extension of an SMA wire of the external length of the actuator in the direction of its extension or contraction.
		As is well-known in the SMA actuator art, per unit length, the mass of wire to be cooled is proportional to the cross-sectional area of the wire (a function of the square of the wire diameter), while the cooling rate is proportional to the surface area of the wire (a function of the diameter).
	www.freepatentsonline.com /6574958.html (11152 words)

	Special Metals - Alloys & Properties
		Shape Memory Ni - Ti Alloys: Alloys having lower Ni:Ti ratio so that they are martensitic at room temperature after cold drawing and heat treating for shape setting.
		Body Temperature NI - Ti Alloy: Alloys formulated to be fully transformed and superelastic at 37oC.
		Superelastic Ni - Ti Alloys: Alloys having a Ni:Ti ratio so that they are superelastic at room temperature when they are cold drawn and tempered.
	www.shape-memory-alloys.com /alloys.html?source=adword_nitinol (215 words)

	Shape Memory Alloys - Frequently Asked Questions
		Shape memory alloys or SMA's are metals that exhibit shape memory properties.
		It allows materials possessing shape memory properties to return to their original shape after having suffered some form of deformation after they are heated to temperatures above their transformation temperature.
		Shape memory alloys can recover from large amounts of bending and torsional deformations as well as small amounts of strain.
	www.azom.com /details.asp?ArticleID=1744 (436 words)

	Shape Memory Alloys
		Shape memory alloys (SMA's) are metals, which exhibit two very unique properties, pseudo-elasticity, and the shape memory effect.
		The un-deformed Martensite phase is the same size and shape as the cubic Austenite phase on a macroscopic scale, so that no change in size or shape is visible in shape memory alloys until the Martensite is deformed.
		The load on the shape memory alloy is increased until the Austenite becomes transformed into Martensite simply due to the loading; this process is shown in Figure 5.
	www.cs.ualberta.ca /~database/MEMS/sma_mems/sma.html (778 words)

	(R&D Horizons) Shape-Memory Alloys Offer Untapped Potential (MDDI archive, Mar 98)
		This ability to memorize shapes allows the creation, for example, of a stent that can be cooled into a compact form and inserted through a catheter into the weakened part of a blood vessel, where body warmth returns it to its expanded shape.
		Alloys that have "double memory" exhibit a reversible effect, with heat causing a reaction that is reversed by cooling.
		Because of the hyperreactivity of the titanium in the alloy, all melting must be done in either a vacuum or an inert atmosphere to eliminate or at least markedly reduce the risk of contamination by oxygen or nitrogen.
	www.devicelink.com /mddi/archive/98/03/005.html (2159 words)

	Shape Memory Alloys - Medical Applications
		A key discovery occurred in 1962, when a binary alloy composed of equi-atomic nickel and titanium was found to exhibit a shape recovery effect when heated after being mechanically deformed.
		The physical performance of the Ni-Ti alloy made it a landmark discovery, and the range of commercially viable applications that have been found for the materials is proof of the importance of the nickel-titanium shape memory alloys.
		The latter means that an SMA in its elastic form can undergo a deformation approximately ten times greater than that of a spring-steel equivalent, and full elastic recovery to the original geometry may be expected.
	www.azom.com /details.asp?ArticleID=134 (1680 words)

	Nanostructured Shape Memory Alloys
		Shape memory alloys continue to be explored for more dramatic superelastic behavior and several of these alloys have already proven to have wide ranging applications in the aerospace, biomedical, and microelectronics industries.
		A nanostructured shape memory alloy is on the leading edge of materials development and will allow further advances in the application of shape memory alloys to microscopic structures and miniaturized devices.
		By starting with a stacked sandwich array of individual alloy components and subjecting this sample arrangement to repeated rolling and folding, the resulting layers are reduced to the nanometer size in bulk form before initiating an alloying and intermediate phase formation reaction.
	mrsec.wisc.edu /Past_projects/Seed_shape_memory/seed_shape_memory_alloys.htm (485 words)

	Expert: Shape Memory Alloys and Polymers Expert
		Superelastic shape memory alloys for various medical instrument applications is a more recent focal point for his studies.
		Mac's recent work has involved the use of shape memory actuators for new concepts in lock nuts, the use of shape memory rings to control the tip clearance in the compressor section of gas turbines, and the application of shape memory torsion devices as the control element in helicopter "smart" rotor blades.
		The use of shape memory alloys, such as nitinol, have also been investigated as actuators in the shape control of surfaces or the correction of surface geometries such as antennas and mirrors.
	www.intota.com /viewbio.asp?bioID=603188&perID=108301 (754 words)

	Shape memory alloy actuated rod for endoscopic instruments (US5645520)
		A construction element that contains a shape memory element which changes shape in response to a change in the temperature of the memory element.
		The temperature is varied by a fluid which flows through channels adjacent to the shape memory element.
		A plurality of shape memory elements can be coupled together to create a robotic arm or an endoscopic instrument.
	www.delphion.com /details?pn=US05645520__ (242 words)

	shape memory alloys
		Shape memory alloys are a class of alloy which employ the shape memory effect.
		The shape memory effect is characterized by a phase change in the material.
		In addition to a displacement actuator, shape memory alloys can be used as a very effective damping device.
	www.mide.com /pdf_html/Shape_Memory_Alloys.htm (264 words)

	AML - Shape Memory Alloys
		Shape memory alloys (SMA) form a group of metals that recover a particular shape when heated above their transformation temperature.
		Thin films of binary and ternary shape memory alloys are produced using a DC magnetron sputtering.
		The shape memory alloy, NiTi, will be used for the pumping mechanism on the micrometer scale.
	aml.seas.ucla.edu /research/areas/shape-memory-alloys/index_old.htm (386 words)

	AML - Shape Memory Alloys
		Shape recovery is due to solid-to-solid phase transformation from martensite to austenite.
		Mohanchandra K.P. As the development of miniaturization in modern technology proceeds, great attention is being paid to thin film shape memory alloys because they are useful as micro actuators in integrated microelectronic mechanical systems (MEMS).
		A new process parameter viz:, hot target, is being used to produce shape memory films.
	aml.seas.ucla.edu /research/areas/shape-memory-alloys/index.htm (386 words)

	TiNi Aerospace, Inc.: Shape Memory Alloy
		SHAPE MEMORY ALLOYS (SMAs) refer to a group of materials which have the ability to return to a predetermined shape when heated.
		The shape memory effect is caused by a temperature dependent crystal structure.
		The most widely used shape memory material is an alloy of Nickel and Titanium called Nitinol.
	www.tiniaerospace.com /sma.html (239 words)

	Fundamental characteristics of nickel-titanium shape memory alloy
		The operating temperature for shape memory devices must not move significantly away from the transformation range, or else the shape memory characteristics may be altered.
		After the initial melting, the alloy transition temperature must be controlled due to the sensitivity of the transition temperature to small changes in the alloy chemistry.
		The use of the one-way shape memory or superelastic property of NiTi for a specific application requires a piece of NiTi to be molded into the desired shape.
	herkules.oulu.fi /isbn9514252217/html/x317.html (2168 words)

	Functionally aded Thin Film Shape Memory Alloy Micro-Actuators
		Shape memory behavior represents a material's ability to recover from large deformations (of approximately 10%) with a thermally induced phase transformation.
		The shape memory material deforms at room temperature, causing a permanent deformation similar to the deformation of copper when wound around the finger.
		The binary alloy of nickel (Ni) and titanium (Ti) is one of the most widely used shape memory materials.
	www.afrlhorizons.com /Briefs/Sept02/OSR0203.html (825 words)

	Halfbakery: shape memory alloy car
		shape memory alloys are a new sort of metal that can be severely deformed, but upon application of an electric current to the metal, the metal regains its original shape; as if the electricity helped the metal remeber its original configuration.
		IIRC SME's only regain shape for a limited level of deformation, beyond which regeneration will not recover the original shape.
		I'd imagine most of the damage in a decent car crash would be beyond the capabilities of SME regeneration to fix.
	www.halfbakery.com /idea/shape_20memory_20alloy_20car (193 words)

	University of Florida News - UF Engineers Probe "Shape Memory" Alloy For Better Prostheses (Site not responding. Last check: 2007-10-12)
		The tiny stents get their so-called “shape memory” from an unusual alloy called nitinol, which exhibits one shape when cool, but forms another when heated.
		Intrigued by the alloy’s biomedical potential, University of Florida researchers have recently begun investigating it for the much larger application of prosthetic limbs.
		The shape memory effect occurs in response to heat, which can be generated through electricity or any other energy source.
	news.ufl.edu /2002/08/14/shapememory (661 words)

	SHAPE MEMORY ALLOY MICRO-THERMOSTAT (Site not responding. Last check: 2007-10-12)
		SMAs are a class of materials that are essentially capable of memorizing different shapes and can convert from shape to shape with ease.
		However, the attractive properties of SMAs have yet to be exploited by thermostat technology on a miniature scale.
		Typical micro-thermostats require external energy to resistively heat the thin film SMA diaphragm to open a normally closed valve and are limited in their deflection and recoverable strain.
	www.research.ucla.edu /tech/ucla05-490.htm (289 words)

	Memory Metalle - FAQ list
		The alloy needs a certain amount of energy (heat flow) to initiate the phase transformation and to move the phase boundary through the alloy.
		Device made out of a shape memory alloy, which is able to provide a significant amount of mechanical work due to the occurance of the phase transformation during heating.
		Special form of the thermal shape memory effect, in which not just the heating but also the cooling of the shape memory element are subject to shape changes.
	www.memory-metalle.de /html/03_knowhow/04_glossary.asp (1077 words)

	Definition of a Shape Memory Alloy <Texas A&M Smart Lab>
		Shape Memory Alloys (SMAs) are a unique class of metal alloys that can recover apparent permanent strains when they are heated above a certain temperature.
		A phase transformation which occurs between these two phases upon heating/cooling is the basis for the unique properties of the SMAs.
		The key effects of SMAs associated with the phase transformation are pseudoelasticity and shape memory effect.
	smart.tamu.edu /overview/smaintro/simple/definition.html (261 words)

	(R&D Digest) Shape-Memory Alloy Could Enhance Prostheses Performance (MDDI archive, Sep 02)
		Nitinol, an unusual alloy that lends shape-memory characteristics to vascular stents and other small-scale products, may someday prove useful in medical devices of much larger size.
		Following studies of biomedical applications of nitinol, researchers at the University of Florida (Gainesville) recently began to explore the potential use of the alloy in the construction of prosthetic limbs.
		The change in shape breaks the bolts, opening a box and releasing a structure such as an antenna.
	www.devicelink.com /mddi/archive/02/09/007.html (599 words)

	Achieve Fish-Like Locomotion by Using Shape Memory Alloy Wires (Site not responding. Last check: 2007-10-12)
		There are several problems with current electro-mechanical or biomechanical robotic fish: detectable noise from servomotors, cost of hardware and electronics package, underwater reliability due to sensitive electronics package in a fresh or saltwater environment, where the possibility of leaking is a real threat, and the duplication of natural fish movement without the use of servomotors.
		This fish is constructed using an innovative composite skeleton and shape memory alloy wires for the muscle structure.
		Also because smart memory alloys are cheaper and more reliable than servomotors the overall cost of the fish will be reduced.
	www.csuohio.edu /chemical_engineering/asee2000/program_files/papers/Lam_Paul_CK_030901.html (266 words)

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