Lightweight titanium aluminide valves and methods for the manufacture thereof

Abstract

Embodiments of a lightweight, high temperature airborne valve are provided. In one embodiment, the airborne vale includes a valve element and a flowbody. The flowbody is formed at least partially from a titanium aluminide alloy and has a flow passage therethrough in which the valve element is movably mounted. Embodiments of a method for producing such a lightweight, high temperature airborne valve are also provided. In one embodiment, the method includes the steps of forming a lightweight flowbody at least partially from a titanium aluminide alloy, hot isostatically pressing the lightweight flowbody, and machining the lightweight flowbody to desired dimensions.

What is claimed is: 
     
         1 . A method for producing a lightweight, high temperature airborne valve, the method comprising the steps of:
 selecting a near-stoichiometric titanium aluminide alloy having a density between approximately 3.5 grams per cubic centimeter and approximately 5.0 grams per cubic centimeter;   pouring the selected near-stoichiometric titanium aluminide alloy into a mold in an enclosure substantially devoid of oxidants to form a lightweight flowbody having a flow passage extending therethrough;   removing the lightweight flowbody from the mold;   hot isostatic pressing the lightweight flowbody;   machining the lightweight flowbody to desired dimensions; and   mounting a valve element in the flow passage of the lightweight flowbody.   
     
     
         2 . The method of  claim 1  wherein the lightweight flowbody is fabricated to include a radial mounting flange, and wherein the method further comprises installing the lightweight, high temperature airborne valve within a pneumatic avionic system deployed aboard an aircraft and utilized to regulate the flow of pressurized air or combustive gasses bled from a gas turbine engine during operation thereof. 
     
     
         3 . The method of  claim 1  further comprising applying an oxidation-resistant coating over at least one surface of the lightweight flowbody after machining the lightweight flowbody to desired dimensions. 
     
     
         4 . The method of  claim 3  wherein applying comprises applying an oxidation-resistant coating over the interior surfaces of the flow passage exposed to hot gas flow during operation of the lightweight, high temperature airborne valve. 
     
     
         5 . The method of  claim 1  wherein the valve element comprises:
 a butterfly disc rotatably mounted within the flow passage; and 
 a wiper seal carried by the butterfly disc and sealingly engaging an inner surface of the lightweight flowbody; and 
 wherein the method further comprises applying a wear-resistant coating over the inner surface of the flow passage contacted by the wiper seal during rotation of the butterfly disc. 
 
     
     
         6 . The method of  claim 1  further comprises bonding at least one machined or hot isostatic pressured part to the titanium aluminide flowbody after machining. 
     
     
         7 . The method of  claim 1  wherein selecting comprises selecting a near-stoichiometric titanium aluminide including at least one of the group consisting of manganese, boron, niobium, molybdenum, and titanium diboride and added to a master alloy during processing of the titanium aluminide alloy. 
     
     
         8 . The method of  claim 1  wherein the selecting comprises selecting a near-stoichiometric titanium aluminide alloy comprising titanium, aluminum, manganese, niobium, and titanium diboride. 
     
     
         9 . The method of  claim 8  wherein selecting comprises selecting a near-stoichiometric titanium aluminide alloy comprising, by weight:
 about 50.2% titanium; 
 about 45.0% aluminum; 
 about 2.0% manganese; 
 about 2.0% niobium; and 
 about 0.8% titanium diboride. 
 
     
     
         10 . The method of  claim 1  wherein selecting comprises selecting a near-stoichiometric titanium aluminide alloy comprising titanium, aluminum, niobium, boron, and molybdenum. 
     
     
         11 . The method of  claim 10  wherein selecting comprises selecting a near-stoichiometric titanium aluminide alloy comprising, by weight:
 about 51.4% titanium; 
 about 43.5% aluminum; 
 about 4.0% niobium; 
 about 0.1% boron; and 
 about 1.0% molybdenum. 
 
     
     
         12 . A method, comprising:
 obtaining a high temperature airborne valve, comprising:
 a lightweight flowbody formed substantially entirely of a near-stoichiometric titanium aluminide alloy having a density between approximately 3.5 grams per cubic centimeter and approximately 5.0 grams per cubic centimeter; and 
 a radial mounting flange extending from the lightweight flowbody; and 
   installing the high temperature airborne valve in a pneumatic avionic system deployed onboard an aircraft by clamping the radial mounting flange of the high temperature airborne valve to a duct included in the pneumatic avionic system and conducting pressurized air flow or combustive gas flow bled from a gas turbine engine during operation thereof.   
     
     
         13 . The method of  claim 12  wherein obtaining comprises obtaining a high temperature airborne valve having a lightweight flowbody formed substantially entirely of a near-stoichiometric titanium alloy comprising titanium, aluminum, manganese, niobium, and titanium diboride. 
     
     
         14 . The method of  claim 12  wherein obtaining comprises obtaining a high temperature airborne valve having a lightweight flowbody formed substantially entirely of a near-stoichiometric titanium alloy comprising titanium, aluminum, niobium, boron, and molybdenum. 
     
     
         15 . A method for producing a lightweight, high temperature airborne valve, the method comprising the steps of:
 selecting a titanium aluminide alloy containing at least one of the group consisting of manganese, boron, niobium, molybdenum, and titanium diboride and added to a master alloy during processing of the titanium aluminide alloy;   pouring the selected titanium aluminide alloy into a mold in an enclosure substantially devoid of oxidants to form a lightweight flowbody having a flow passage extending therethrough;   removing the lightweight flowbody from the mold;   machining the lightweight flowbody to desired dimensions; and   mounting a valve element in the flow passage of the lightweight flowbody.   
     
     
         16 . The method of  claim 15  wherein the selecting comprises selecting a titanium aluminide alloy comprising titanium, aluminum, manganese, niobium, and titanium diboride. 
     
     
         17 . The method of  claim 16  wherein selecting comprises selecting a titanium aluminide alloy comprising, by weight:
 about 50.2% titanium; 
 about 45.0% aluminum; 
 about 2.0% manganese; 
 about 2.0% niobium; and 
 about 0.8% titanium diboride. 
 
     
     
         18 . The method of  claim 15  wherein selecting comprises selecting a titanium aluminide alloy comprising titanium, aluminum, niobium, boron, and molybdenum. 
     
     
         19 . The method of  claim 18  wherein selecting comprises selecting a titanium aluminide alloy comprising, by weight:
 about 51.4% titanium; 
 about 43.5% aluminum; 
 about 4.0% niobium; 
 about 0.1% boron; and 
 about 1.0% molybdenum. 
 
     
     
         20 . The method of  claim 15  wherein selecting comprises selecting a titanium aluminide alloy formulated to have a titanium-to-aluminide ratio of approximately 1:1 on the atomic scale.