United States of America As Represented by the Secretary of the Air Force

Other

Daniel Eylon

Francis H Froes

Paul R Smith, Jr

Russell G Vogt

Steven J Savage

William C Revelos

Charles F Yolton

Paul R Smith

Lev J Levin

Shiro Fujishiro

Leslie S Apgar

Isaac Weiss

Stephen W Schwenker

Gerhard E Welsch

Karen R Teal

Gerhard E Wesch

A method to produce high temperature oxidation resistant metal matrix composites by fiber diameter grading, which comprises the steps of (a) laying up an alloy/fiber preform consisting of a plurality of alternating layers of metal alloy and fibers and (b) consolidating the preform under suitable conditions, wherein the layers of fibers in the preform are graduated so that fiber density is lower nearer what will become the exposed surface of the composite and higher toward the interior of the composite. The difference in fiber density is achieved by spacing the near-surface fibers further apart than the interior fibers.

Method to produce high temperature oxidation resistant metal matrix composites by fiber density grading

A method for protecting a titanium aluminide substrate against environmental degradation at higher temperatures, which comprises applying a layer of a ductile titanium alloy to at least one exterior surface of the substrate and applying an oxidation resistant coating to the exterior surface of the ductile layer. The titanium aluminide substrate may be monolithic or a fiber-reinforced composite structure. The oxidation resistant coating is an ion-plated coating of (a) a noble metal, such as gold or platinum, or (b) a coating of tungsten followed by an ion-plated coating of a noble metal.

Titanium aluminide articles having improved high temperature resistance

A method to produce high temperature oxidation resistant metal matrix composites by fiber diameter grading which comprises the steps of (a) laying up an alloy/fiber preform consisting of a plurality of alternating layers of metal alloy and fibers and (b) consolidating the preform under suitable conditions, wherein fibers of at least two diameters are employed and wherein the layers of fibers in the preform are graduated so that larger diameter fibers are located nearer what will become the exposed surface of the composite and smaller diameter fibers are located toward the interior of the composite.

Method to produce high temperature oxidation resistant metal matrix

The microstructure of alpha-2 and orthorhombic titanium aluminide alloy cast and ingot metallurgy articles is refined by: (a) hydrogenating the article at a temperature at or slightly below the .beta.-transus temperature of the alloy; (b) cooling the article, under a positive partial pressure of hydrogen, to a temperature about 20 to 40 percent below the .beta.-transus; and (c) dehydrogenating the article.

Method to refine the microstructure of .alpha.-2 titanium

An internally reinforced hollow structure is described which comprises a layer of titanium metal matrix composite applied to the internal surfaces of structural segments comprising the hollow structure, the segments then being joined to form the desired hollow structure.

Internally reinforced hollow titanium alloy components

A method for producing hot worked gamma titanium aluminide alloy articles which comprises the steps of:

Method to produce hot-worked gamma titanium aluminide articles

The fracture resistance of titanium alloy matrix composites is increased by one of two methods. One method comprises the steps of consolidating a titanium alloy-fiber preform under suitable conditions to provide a metal matrix composite and thermally treating the thus-prepared composite at a temperature above the beta-transus temperature of the alloy for a brief time. In the second method, a composite having increased fracture resistance is produced by consolidating an alloy-fiber preform at a temperature above the normal consolidation temperature for a time less than the normal consolidation time.

Method for increasing the fracture resistance of titanium composites

A method to increase the fracture resistance of titanium alloy matrix composites which comprises thermally treating a composite at a temperature about 5 to 10% above the beta-transus temperature of the alloy for about 4 to 60 minutes.

Post-consolidation method for increasing the fracture resistance of

A method for producing hollow titanium alloy articles which comprises casting a plurality of segments which can be joined to provide a unitary, hollow article, treating the cast segments in such manner as to refine the microstructure of the segments and superplastic forming/diffusion bonding the segments into the desired hollow article.

Method to produce hollow titanium alloy articles

A method for producing fiber reinforced titanium alloy articles which comprises casting a plurality of segments which can be joined to provide a unitary article, wherein at least one-half of the segments comprise at least one shallow cavity, treating the cast segments in such manner as to refine the microstructure of the segments, filling the cavity or cavities with reinforcing fibers and superplastic forming/diffusion bonding the segments into the desired article.

Method to produce selectively reinforced titanium alloy articles

A method for fabricating a titanium aluminide composite structure consisting of a filamentary material selected from the group consisting of silicon carbide, silicon carbide-coated boron, boron carbide-coated boron, titanium boride-coated silicon carbide and silicon-coated silicon carbide, embedded in an alpha-2 titanium aluminide metal matrix, which comprises the steps of providing a beta-stabilized Ti.sub.3 Al foil containing a sacrificial quantity of beta stabilizer element in excess of the desired quantity of beta stabilizer, fabricating a preform consisting of alternating layers of foil and a plurality of at least one of the aforementioned filamentary materials, and applying heat and pressure to consolidate the preform. In another embodiment of the invention, the beta-stabilized Ti.sub.3 Al foil is coated on at least one side with a thin layer of sacrificial beta stabilizer. The composite structure fabricated using the method of this invention is characterized by its lack of a denuded zone and absence of fabrication cracking.

Method to fabricate titanium aluminide matrix composites

A method for fabricating a composite structure consisting of a filamentary material selected from the group consisting of silicon carbide, silicon carbide-coated boron, boron carbide-coated boron, titanium boride-coated silicon carbide and silicon-coated silicon carbide, embedded in an alpha-2 titanium aluminide metal matrix, which comprises the steps of modifying the desired filamentary material with at least one beta stabilizer, providing a beta-stabilized Ti.sub.3 Al foil, fabricating a preform consisting of alternating layers of foil and a plurality of at least one of the beta stabilizer-coated filamentary materials, and applying heat and pressure to consolidate the preform. The composite structure fabricated using the method of this invention is characterized by its lack of a denuded zone and absence of fabrication cracking.

Method to manufacture titanium aluminide matrix composites

A method of producing titanium alloy articles having a desired microstructure which comprises the steps of:

Method for producing very fine microstructures in titanium aluminide

A method for producing titamium alloy articles having a desired microstructure which comprises the steps of:

Method to produce improved property titanium aluminide articles

An improved process for producing near-alpha and alpha+beta titanium alloy axisymmetric components with high fatigue resistance which comprises the steps of:

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Dayton, OH, United States of America

Daniel Eylon