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Publication numberUS3012882 A
Publication typeGrant
Publication dateDec 12, 1961
Filing dateJan 26, 1960
Priority dateJan 26, 1960
Publication numberUS 3012882 A, US 3012882A, US-A-3012882, US3012882 A, US3012882A
InventorsMuldawer Leonard, Feder Ralph
Original AssigneeMuldawer Leonard, Feder Ralph
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Temperature responsive cadmium-silver-gold alloys
US 3012882 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

United States Patent Ofiice 3,012,882 Patented Dec. 12., 1961 3,012,882 7 TEMPERATURE RESPONSIVE CADMIUM- SILVER-GOLD ALLOYS Leonard Muldawer, Bala-Cynwyd, and Ralph Feder, Philadelphia, Pa., assignors to the United States of America as represented by the Secretary of the Army Filed Jan. 26, 1960, Ser. No. 4,838 3 Claims. (Cl. 75-134) This invention relates to metal alloys and more especially to a metal alloy which undergoes a phase change 'at a temperature which is dependent on its composition and its previous treatment.

It is known that certain gold-cadmium alloys undergo a phase change when exposed to a critical temperature which is hereinafter designated as T5. Thus rods of these alloys are flexible at temperatures below T and rigid at temperatures above T If such a rod is subjected to a transverse force in its flexible condition, it will suddenly straighten when heated to T As a result of this characteristic such rods are capable of producing mechanical effects when their temperature is raised or lowered through their critical temperatures.

T has a value which is close to 70 C. in the case of an alloy consisting of 52.5% atomic percent gold and 47.5 atomic percent cadmium. It is the purpose of the present invention to extend the range of temperatures at which a phase change in the alloy may be realized. This is advantageous in that a member consisting of the alloy may be made to produce a mechanical effect at any selected temperature within a wide range of temperatures. It is accomplished by replacing variable atomic percentages of gold by silver.

The invention will be better understood from the following description when considered in connection with the accompanying drawings and its scope is indicatedby the appended claims.

Referring to the drawings:

FIG. 1 illustrates one of the many possible uses' of the alloy,

FIG. 2 indicates the positions assumed by the free end of a Au Cd rod in response to various temperatures, and

FIG. 3 indicates the relation between T and the atomic percentage of gold replaced by silver in alloy (AuAg) Cd curve A showing this relation as the temperature is raised through T and curve B showing this relation as the temperature is loweredthrough' T The switch of FIG. 1 includes a movable contact and fixed contacts 11 and 12. The contact 10 is fixed to the free end of a rod 13 consisting of an alloy of the type discussed above. The opposite end of the rod 13 is fixed to a support 14. Connected between the contacts 10 and 11 are the rod 13, a power source shown as a battery 15 and a load device 16. Similarly connected between the contacts 10 and 12 are a battery 17 and a load device 18. The rod 13' has a transverse force applied to it by a spring 19.

Under these conditions, the contacts 10 and 11 are engaged when the temperature is raised through T and the contacts 10 and 12 are engaged when the temperature is lowered through T If the rod 13 has a length of 8.7 cm., a diameter of 1 mm., a composition of A-u -"a--Cd and is subjected to a pull of 12 gm., the position of the contact 10 at various temperatures is indicated by the curve of FIG. 2. It can be seen from this curve that there is a sudden change in the position of the end of the rod 13 and the movable contact 10 at the temperature T.,.

The beta range for Au-Cd alloys has an appreciable width and the transformation of the cubic phase into a lower symmetry phase takes place at a temperature which depends upon the percentages of gold and cadmium. Thus the 47.5% Cd alloy shows a T at about 60 C. on cooling and about C. on heating. The 49.0% Cd alloy shows a T at about 30 C. on cooling and about 35 C. on heating. The maximum range in T for pure Au-Cd alloy is therefore about 75 C. since alloys can be made over a 3 or 4% range.

We have found that this maximum range of 75 C. in T maybe greatly extended by substituting third elements for various percentages of the gold or cadmium. The ad vantages of such substitutions are that much greater changes in T can be produced and that the phase transformation maintains the same character. Thus alloys of 47.5% Cd, with the remainder either all gold or all silver, undergo similar transformations.

FIG. 3 shows T for alloys from Au -Cd to Ag Cd these percentages being atomic in all cases as previously indicated. In this figure, curves A and B show the variation in T as the percentage of silver is changed, curve A indicating the change in T when the temperature is raised through T and curve B indicating the change in T when the temperature is lowered through T It can be seen from these curves that T for raising the temperature through the critical value is somewhat higher than the T for lowering the temperature through the critical value.

The particular alloy to be chosen depends on the temperature at which the mechanical efifect is to be produced. As can be 'seen from FIG. 3, T values from about +70 C. to about -160 C. are available. While the silvergold-cadmium alloy has been shown as applied to an electrical switching device, this is only one of the many applications possible. Other uses of it to produce mechanical stood by those skilled in the art.

As shown in FIG. 1, the alloy rod itself is part of the electrical circuit but this need not be the case. It may be used to produce mechanical effects which may include the operation of electrical switches.

We claim:

1. An alloy having critical temperatures at which it changes phase, said critical temperatures being about 60 C. and 40 C. when said alloy is heated and cooled respectively through said critical temperatures, said alloy consisting essentially of 47.5 atomic percent cadmium, about 2.5 atomic percent silver and about 50.0 atomic percent gold.

2. An alloy having critical temperatures at which it changes phase, said critical temperatures being about 0 C. and -6 C. when said alloy is heated and cooled respectively through said critical temperatures, said alloy consisting essentially of 47.5 atomic percent cadmium, about 10 atomic percent silver and about 42.5 atomic percent gold.

3. An alloy having critical temperatures at which it changes phase, said critical temperatures being about l45 C. and C. when said alloy is heated and cooled respectively through said critical temperatures,

said alloy consisting essentially of 47.5 atomic percent Gleason Mar. 23, 1915 Wiegand Apr. 21, 1942

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US1133019 *May 13, 1912Mar 23, 1915Richard H KingProcess of making alloys.
US2280137 *Aug 4, 1939Apr 21, 1942Huenefeld CompanyMethod of fabricating thermoelectric elements
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3622941 *Oct 30, 1968Nov 23, 1971Raychem CorpHeat recoverable article with mechanical insert
US3634803 *Jul 22, 1969Jan 11, 1972Robertshaw Controls CoTemperature-responsive switch assemblies
US3913444 *Nov 8, 1972Oct 21, 1975Raychem CorpThermally deformable fastening pin
US4035007 *Oct 29, 1973Jul 12, 1977Raychem CorporationHeat recoverable metallic coupling
US4198081 *May 26, 1977Apr 15, 1980Raychem CorporationHeat recoverable metallic coupling
US4205293 *Apr 28, 1978May 27, 1980Bbc Brown Boveri & Company LimitedThermoelectric switch
US4310354 *Jan 10, 1980Jan 12, 1982Special Metals CorporationProcess for producing a shape memory effect alloy having a desired transition temperature
US4468076 *Jul 23, 1982Aug 28, 1984Raychem CorporationArray package connector and connector tool
US4522457 *Oct 7, 1983Jun 11, 1985Raychem CorporationCompliant connecting device with heat-recoverable driver
US4553393 *Aug 26, 1983Nov 19, 1985The United States Of America As Represented By The Administrator Of The National Aeronautics And Space AdministrationMemory metal actuator
US4559512 *Dec 28, 1984Dec 17, 1985Raychem CorporationSelf-protecting and conditioning memory metal actuator
US4621844 *Sep 6, 1984Nov 11, 1986Shell Oil CompanyMemory metal connector
US4759293 *Jun 17, 1987Jul 26, 1988Davis Jr Thomas OArticle using shape-memory alloy to improve and/or control the speed of recovery
US4839479 *Jul 18, 1988Jun 13, 1989Davis Jr Thomas OArticle using shape-memory alloy to improve and/or control the speed of recovery
US6485507Jul 28, 1999Nov 26, 2002Scimed Life SystemsMulti-property nitinol by heat treatment
US6997947Nov 26, 2002Feb 14, 2006Boston Scientific Scimed, Inc.Multi-property nitinol by heat treatment
US7464548 *Nov 30, 2005Dec 16, 2008The Boeing CompanyShape memory alloy linear actuator
US8025495Sep 27, 2011Cook Medical Technologies LlcApparatus and method for making a spider occlusion device
US8308752Nov 13, 2012Cook Medical Technologies LlcBarrel occlusion device
US8480707Jul 31, 2009Jul 9, 2013Cook Medical Technologies LlcClosure device and method for occluding a bodily passageway
US8617205Jun 10, 2010Dec 31, 2013Cook Medical Technologies LlcClosure device
US8734483Aug 27, 2007May 27, 2014Cook Medical Technologies LlcSpider PFO closure device
US9023074May 1, 2012May 5, 2015Cook Medical Technologies LlcMulti-stage occlusion devices
US9332977Nov 8, 2013May 10, 2016Cook Medical Technologies LlcClosure device
US20030109918 *Nov 26, 2002Jun 12, 2003Scimed Life Systems, Inc.Multi-property nitinol by heat treatment
US20070119165 *Nov 30, 2005May 31, 2007The Boeing CompanyShape memory alloy linear actuator
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DE3007307A1 *Feb 27, 1980Jul 23, 1981Bbc Brown Boveri & CieDetachable shrunk joint - uses shape memory alloy with two=way effect
WO2001008600A2Jun 22, 2000Feb 8, 2001Scimed Life Systems, Inc.Nitinol medical devices having variable stifness by heat treatment
Classifications
U.S. Classification148/402, 420/511, 337/393, 411/409, 439/932
International ClassificationC22F1/00, H01R4/01, H01H37/32, C22C5/02
Cooperative ClassificationC22C5/02, Y10S439/932, C22F1/006, H01R4/01, H01H37/323
European ClassificationH01H37/32B, C22C5/02, C22F1/00M, H01R4/01