High temperature shape memory alloy actuators

Abstract

A high temperature component having an actuator body including an actuatable portion comprising a shape memory alloy containing one more of Ni, Al, Nb, Ti and Ta and a platinum-group metal. The shape memory alloy has an altered geometry at a predetermined temperature. The actuator is also capable of operation in and is resistant to high temperature oxidizing atmospheres. A method for forming an actuator and a method for high temperature control are also disclosed.

1 . A high temperature gas turbine engine component comprising:
 an actuator body, the actuator body having an actuatable portion comprising a nickel-aluminum shape memory alloy containing one more elements selected from the group consisting of Nb, Ti, Ta and combinations thereof and a platinum-group metal selected from the group consisting of Pt, Pd, Rh, Ru, Ir and combinations thereof, the nickel-aluminum based shape memory alloy having an altered geometry above a predetermined temperature; and   wherein a portion of the actuator body is bonded to a surface of the high temperature gas turbine component along a wheelspace path, and wherein the altered geometry of the actuatable portion disrupts a gas flow path through the wheelspace path; and   wherein the actuator body is resistant to high temperature oxidizing atmospheres.   
     
     
         2 . (canceled) 
     
     
         3 . The turbine engine component of  claim 1 , wherein the predetermined temperature is reached or exceeded by the turbine engine component during operation, the actuatable portion being substantially in a martensite phase below the predetermined temperature and substantially in an austenite phase above the predetermined temperature. 
     
     
         4 . (canceled) 
     
     
         5 . (canceled) 
     
     
         6 . The turbine engine component of  claim 1 , wherein the actuator body further comprises a superalloy. 
     
     
         7 . The turbine engine component of  claim 1 , wherein the shape memory alloy is resistant to oxidation at a temperature up to about 1150° C. 
     
     
         8 . The turbine engine component of  claim 1 , wherein the nickel-aluminum based shape memory alloy comprises an alloy of the following formula:
   (A 1−x PGM x ) 0.5+y B 0.5−y      wherein A is an element selected from the group consisting of Ni, and combinations of Ni and Co or Fe; B is an element selected from the group consisting of Al, and combinations of Al and Cr, Hf, Zr, La, Y, Ce, Ti, Mo, W, Nb, Re, Ta or V; PGM is a platinum-group element selected from the group consisting of Pt, Pd, Ru, Rh, Ir and combinations thereof, x is from greater than 0 to about 1 atomic fraction and y is from about 0 to about 0.23 atomic fraction.   
     
     
         9 . The turbine engine component of  claim 8 , wherein the nickel-aluminum based shape memory alloy comprises an alloy of the following formula:
   (A 1−x PGM x ) 0.5+y B 0.5−y      wherein x is from about 0.05 to about 0.6 atomic fraction, and y is from about 0.01 to about 0.2 atomic fraction.   
     
     
         10 . The turbine engine component of  claim 1 , wherein the nickel-aluminum based shape memory alloy comprises an alloy of the following formula:
   (A 1−x PGM x ) 0.5+y B 0.5−y      wherein A is substantially Ni and Co, PGM is one or both of Pt and Pd, B is substantially Al and Ti, and the ratio of Ti to Al is from about 0.1 to about 10, x is from greater than 0 to about 1 atomic fraction and y is from about 0 to about 0.23 atomic fraction.   
     
     
         11 . The turbine engine component of  claim 8 , wherein the nickle-aluminum based shape memory alloy comprises an alloy of the following formula:
   (A 1−x PGM x ) 0.5+y B 0.5−y      wherein B further comprises up to 10 at % Cr and up to 2 at % of one or both of Hf, Zr, and Y.   
     
     
         12 . A high temperature gas turbine engine component comprising:
 an actuator body, the actuator body having an actuatable portion comprising a shape memory alloy, wherein the shape memory alloy comprises an alloy of the following formula:
   Ru 0.5+y (Nb 1−x Ta x ) 0.5−y    
   wherein x is from about 0 to about 1 atomic fraction, and y is from about −0.06 to about 0.23 atomic fraction, the shape memory alloy having an altered geometry above a predetermined temperature;   wherein a portion of the actuator body is bonded to a surface of the high temperature gas turbine component along a wheelspace seal path, and wherein the altered geometry of the actuatable portion disrupts a gas flow path through the wheelspace seal path; and   wherein the actuator body is resistant to high temperature oxidizing atmospheres.   
     
     
         13 . A method for forming a high temperature actuator body comprising:
 providing a shape memory alloy containing one more elements selected from the group consisting of Ni, Al, Nb, Ti, Ta and combinations thereof and a platinum-group metal selected from the group consisting of Pt, Pd, Rh, Ru, Ir and combinations thereof;   heating the alloy to a predetermined elevated temperature;   deforming the alloy to a geometry at the predetermined high temperature to impart the high-temperature shape; and   cooling the alloy to form a high temperature shape memory actuator portion.   
     
     
         14 . The method of  claim 13 , wherein the body is further configured to modify a gas flow path at an elevated temperature. 
     
     
         15 . The method of  claim 13 , wherein the process further comprises affixing the actuator portion to a gas turbine engine component 
     
     
         16 . The method of  claim 13 , wherein affixing comprises a process selected from the group consisting of mechanical joining, deposition, metallurgical bonding and combinations thereof. 
     
     
         17 . The method of  claim 16 , wherein the affixing is mechanical bonding selected from the group consisting of riveting, bolting, bracing, wire tying and combinations thereof. 
     
     
         18 . The method of  claim 13 , wherein the affixing is deposition selected from the group consisting of arc spray, electro-spark deposition, laser cladding, vacuum plasma spray, inert gas shrouded thermal spray, plasma transfer arc, physical vapor deposition, vacuum arc deposition and combinations thereof. 
     
     
         19 . The method of  claim 13 , wherein the affixing is metallurgically bonding selected from the group consisting of brazing, co-extrusion, explosion bonding, hot-isostatic-pressing (HIP), roll-bonding, forge-bonding, diffusion bonding, translational friction welding, fusion welding, friction-stir welding, inertia welding and combinations thereof 
     
     
         20 . A method for providing high temperature actuation comprising:
 providing a high temperature actuator, the actuator comprising:   an actuator body, the actuator body having an actuatable portion comprising a shape memory alloy containing one more elements selected from the group consisting of Ni, Al, Nb, Ti, Ta and combinations thereof and a platinum-group metal selected from the group consisting of Pt, Pd, Rh, Ru, Ir and combinations thereof, the shape memory alloy having an altered geometry above a predetermined temperature; and   exposing the actuator to a predetermined temperature to provide the actuatable portion with a desired geometry.   
     
     
         21 . The method of  claim 20 , wherein the predetermined temperature is a temperature above which the actuatable portion exhibits a substantially austenite phase, the predetermined temperature being a temperature above which the turbine engine component is disposed or operates in the deployed state. 
     
     
         22 . The method of  claim 20 , wherein the altered geometry modifies a gas flow path. 
     
     
         23 . The method of  claim 20 , wherein the actuator body is affixed to or is adjacent to a component selected from the group consisting of a turbine nozzle, a turbine exhaust structure, a turbine shroud, a turbine shroud hanger, a turbine blade, a turbine disk, a hot gas path seal, a combustor and combinations thereof. 
     
     
         24 . The method of  claim 20 , wherein the actuator body is fabricated into a component selected from the group consisting of a turbine nozzle, a turbine exhaust structure, a turbine shroud, a turbine shroud hanger, a turbine blade, a turbine disk, a hot gas path seal, a combustor and combinations thereof.