United Technologies Corporation

Eugene J Delgrosso

Francis S Galasso

Urban E Kuntz

Carl Edwin Carlson

John A Violette

Michael R Coles

James Augustus Jennings

A hybrid braze alloy is disclosed that includes an aluminum alloy and a magnesium alloy mixed together. In use of the hybrid braze alloy, the ratio by weight of aluminum alloy to magnesium alloy making up the mixture may be altered within a working braze ratio range of about forty nine to one (49/1) to about four point eight to one (4.8/1), so that the braze melting temperature of the hybrid braze alloy is a function of the ratio. By altering the ratio of the alloys within the working braze ratio range, a braze melting temperature may be achieved that is most appropriate for brazing a specific component to a specific apparatus.

Hybrid braze alloy

A lightweight propulsor blade (10) is constructed 10 of a hollow internal spar (30) and an exterior airfoil shell (20) which defines and encompasses a hollow interior cavity (26). The internal spar (30) is disposed within the cavity 26 and extends spanwisely from its tip portion to terminate in a spar root portion (40). The spar has at least forward and aft spanwisely extending, chordwisely spaced, hollow box-like cavities (52A, 52B), a leading edge shear web (53) projecting chordwisely forward from the forward cavity (52A), a trailing edge shear web (55) projecting chordwisely rearward from the aft cavity (52B), and an intermediate chordwise shear web (57) spanning the space between and interconnecting the forward and aft cavities (52A, 52B). An additional intermediate box-like cavity (52C) may be incorporated in the intermediate chordwise shear web (57) in spaced relationship between the forward and aft cavities (52A, 52B).

Lightweight propulsor blade with internal spars and rigid base members

The low pressure braze bonding of members comprised of, for example, titanium and zirconium alloys is accomplished with the use of foil-type braze alloy preforms. The braze alloy preforms comprise a titanium-zirconium foil which has been coated on at least one side with a layer of nickel which functions as a eutectic depressant alloying agent. Upon heating, at a temperature below the beta transus of titanium, a liquid phase will form and the nickel will partially alloy with and migrate into the foil and workpieces and solidification of the resulting joint may thereafter be obtained.

Composite foil preform for high temperature brazing

Members comprised of materials such as titanium and zirconium and their alloys are bonded together in a non-reacting environment with the aid of foil-type braze alloy preforms. The preforms are positioned between the members to be joined, pressure is applied and the joint assembly is subjected to a temperature in excess of 1550.degree. F but below the beta transus of the members. The preforms are fabricated from a titanium-zirconium foil to which a eutectic depressant alloying agent has been added. The depressant forms, with the titanium and zirconium, a low melting point eutectic which, with extended isothermal heating, will diffuse into the base materials.

Diffusion bonding utilizing eutectic fugitive liquid phase

The diffusion brazing of members comprised of materials which are characterized by embrittlement as a result of exposure to excessive temperatures is accomplished with the aid of preforms consisting of a titanium-zirconium alloy foil coated with a plurality of eutectic depressant alloying agents. The depressant agents, in a preferred embodiment, are applied as layers and consist of beryllium and nickel. The preforms are sandwiched between surfaces to be joined and the resulting assemblies are heated in a non-reactive environment with light pressure loading whereby a liquid phase will result and diffusion of metal from the preform into the base metals will occur.

High temperature titanium braze foil

A method for producing a generally bifurcated metal protective sheath for the edge of an aerodynamic blade comprising the steps of (1) providing a metal sheath mid-section element having a top and bottom surface, (2) covering the top and bottom surface with an aluminum bonding material, (3) laying up separate metal top and bottom sheath cover elements on each of the top and bottom surfaces of the mid-section element to cover and overhang the same, the aluminum bonding material having a solidus temperature lower than the solidus temperatures of the mid-section element and the top and bottom cover elements, and (4) subjecting the layup to heat and pressure in a die for a time sufficient to bring the temperature of the bonding material to a temperature which is below but within approximately 20.degree. F of its solidus temperature to solid state diffusion bond the mid-section and cover elements together without forming intermetallics.

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Wallingford, CT, United States of America

Eugene J Delgrosso