US4043498A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of plastic flow diffusion bonding
Assignee: Astech MCI Manufacturing Inc
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Filing: 1975-09-15
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Granted: 1977-08-23
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Expires: 1995-09-15
Abstract
Abstract The present invention relates to a method for diffusion bonding metallic detail parts to form a structural component. This invention presents an efficient low cost method of establishing and maintaining the required intimate surface contact for solid state diffusion bonding. This contact is achieved by configuring the metallic details such that sufficient stability is present to permit applying bonding forces sufficiently great to plastic flow the to-be-joined surfaces into intimate contact. The self-stability of the detail parts eliminates the need for support tooling and the plastic flow to achieve intimate contact eliminates the need for close tolerance preparation of the detail parts. This method is particularly applicable to the fabrication of hollow internally stiffened structural components in which the shell skins are non-parallel; such as turbofan/turbojet engine vanes and blades.
Inventors
- 👤 Charles E. Conn, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 01:29
CPC Classifications
B; B23; B23K; B23K11/00; B23K11/002; B23K11/0093; B23K20/00; B23K20/02; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49316; Y10T29/49336; Y10T29/49339
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
378 words
A method for fabricating an internally stiffened, aerodynamically shaped shell structure comprising the steps of: a. providing first and second metallic face sheets having an excess volume of metallic material on at least one of said face sheets; b. Placing said first sheet in a die assembly which is configured to produce the desired basic aerodynamic shaped structure, said first face sheet having means to align said first face sheet in said die assembly; c. placing at least one self-stable internal stiffener fabricated from metallic material upon said first face sheet, sand internal stiffener having a sufficient thickness to provide an adequate bonding area for joining the stiffener to the face sheets, a configuration which allows said self-stable member to provide sufficient support during the subsequent joining of said self-stable member to said face sheets, first and second ends which are received in said die assembly, and a height dimension which is greater than the net height requirement by approximately 0.01 to 0.08 inches to provide sufficient excess volume of said metallic material so as to provide positive fill in said die assembly for the desired amount of plastic flow of such material, and aligning said stiffener with respect to said first face sheet; d. placing said second face sheet in said die assembly over said internal stiffener, said second face sheet having means to align said second face sheet in said die; e. applying a forming an joining force to said internally stiffened structure for a sufficient duration at sufficient elevated temperature to cause intimate contact between opposed longitudinal edges of said face sheets and between said self-stable stiffener and adjacent areas of said face sheets by plastic flowing the excess volumes of material in the height of said self-stable internal stiffener and along the longitudinal edges of said face sheets, so as to join and bond said self-stable stiffener by solid state diffusion bonding to said face sheets and to join and bond said opposed longitudinal edges by homogeneous solid state diffusion bonding, thereby producing an aerodynamically shaped structure with leading and trailing edges, said forming and joining force being substantially localized in the to-be-joined areas and determined by the amount of excess material to be flowed and the plastic flow characteristics of the metal used.
Claim 2
Independent Claim
378 words
A method for fabricating an internally stiffened, aerodynamically shaped shell structure comprising the steps of: a. providing first and second metallic face sheets having an excess volume of metallic material on at least one of said face sheets; b. Placing said first sheet in a die assembly which is configured to produce the desired basic aerodynamic shaped structure, said first face sheet having means to align said first face sheet in said die assembly; c. placing at least one self-stable internal stiffener fabricated from metallic material upon said first face sheet, sand internal stiffener having a sufficient thickness to provide an adequate bonding area for joining the stiffener to the face sheets, a configuration which allows said self-stable member to provide sufficient support during the subsequent joining of said self-stable member to said face sheets, first and second ends which are received in said die assembly, and a height dimension which is greater than the net height requirement by approximately 0.01 to 0.08 inches to provide sufficient excess volume of said metallic material so as to provide positive fill in said die assembly for the desired amount of plastic flow of such material, and aligning said stiffener with respect to said first face sheet; d. placing said second face sheet in said die assembly over said internal stiffener, said second face sheet having means to align said second face sheet in said die; e. applying a forming an joining force to said internally stiffened structure for a sufficient duration at sufficient elevated temperature to cause intimate contact between opposed longitudinal edges of said face sheets and between said self-stable stiffener and adjacent areas of said face sheets by plastic flowing the excess volumes of material in the height of said self-stable internal stiffener and along the longitudinal edges of said face sheets, so as to join and bond said self-stable stiffener by solid state diffusion bonding to said face sheets and to join and bond said opposed longitudinal edges by homogeneous solid state diffusion bonding, thereby producing an aerodynamically shaped structure with leading and trailing edges, said forming and joining force being substantially localized in the to-be-joined areas and determined by the amount of excess material to be flowed and the plastic flow characteristics of the metal used.
Claim 3
Dependent Claim
32 words
The method of claim 1 wherein said internal stiffener and said face sheets are provided with tabs at each end thereof and said tabs are received in slots in said indexing means.
Claim 4
Dependent Claim
32 words
The method of claim 1 wherein said forming and joining forces are applied in an inert atmosphere at a temperature below the transformation temperature of the metal in said internally stiffened structure.
Claim 5
Dependent Claim
19 words
The method of claim 3 wherein said inert atmosphere is a vacuum of at least approximately 10 -4 Torr.
Claim 6
Dependent Claim
52 words
The method of claim 3 wherein said forming and joining force is applied by the action of a die ram of a die assembly when said die assembly is installed within means for applying pressure the shape of said die ram being configured to achieve the desired contours of said aerodynamic structure.
Claim 7
Dependent Claim
29 words
The method of claim 3 wherein said die assembly is enclosed in metallic members which form a retort envelope, said retort envelope being configured to maintain said inert atmosphere.
Claim 8
Dependent Claim
29 words
The method of claim 3 wherein said die assembly is placed within an inert atmosphere furnace press, said furnace press being configured to maintain said inert atmosphere and temperature.
Claim 9
Dependent Claim
20 words
The method of claim 1 wherein a plurality of internal stiffeners are disposed between said first and second face sheets.
Claim 10
Dependent Claim
50 words
The method of claim 1 which said self-stable stiffener and said first and second face sheets are made of a metal selected from the group consisting of the wrought materials of titanium base alloys, aluminum base alloys, stainless steel alloys, nickel base alloys, cobalt base alloys and columbium base alloys.
Claim 11
Dependent Claim
23 words
The method of claim 1 in which said self-stable stiffener and said first and second face sheets are made of titanium base alloys.
Claim 12
Dependent Claim
12 words
The internally stiffened structure made by the method defined in claim 1.
Claim 13
Independent Claim
358 words
A method for fabricating an internally stiffened, aerodynamically shaped shell structure comprising the steps of: providing first and second metallic face sheets having a predetermined excess volume of material along the longitudinal edges of at least one of said face sheets and having a greater thickness than is required for the basic shell structure along said longitudinal edges and a reduced thickness away from the edges; b. placing said first sheet in a die assembly which is configured to produce the desired basic aerodynamic shaped structure, said first face sheet having means to align said first face sheet in said die assembly; c. placing at least one metallic self-stable internal stiffener upon said first face sheet, said internal stiffener having a sufficient thickness to provide an adequate bonding area for joining the stiffener to the face sheets, a configuration which allows said self-stable member to provide sufficient support during the subsequent joining of said self-stable member to said face sheets, and a predetermined excess volume of material in its height dimension, and aligning said stiffener with respect to said first face sheet; d. placing said second face sheet in said die assembly over said internal stiffener, said second face sheet having means to align said second face sheet in said die; e. applying a forming and joining force to said internally stiffened structure for a sufficient duration at sufficient elevated temperature to cause intimate contact between opposed longitudinal edges of said face sheets and between said self-stable stiffener and adjacent areas of said face sheets by plastic flowing the predetermined excess volumes of material in the height of said self-stable internal stiffener and along the longitudinal edges of said face sheets so as to join and bond said self-stable stiffener by diffusion bonding to said face sheets and to join and bond said opposed longitudinal edges, said excess volume of flow material causing increased solidity, thereby producing an aerodynamically shaped structure with leading and trailing edges, said forming and joining force being substantially localized in the to-be-joined areas and determined by the amount of excess material to be flowed and the plastic flow characteristics of the metal used.
Claim 14
Independent Claim
358 words
A method for fabricating an internally stiffened, aerodynamically shaped shell structure comprising the steps of: providing first and second metallic face sheets having a predetermined excess volume of material along the longitudinal edges of at least one of said face sheets and having a greater thickness than is required for the basic shell structure along said longitudinal edges and a reduced thickness away from the edges; b. placing said first sheet in a die assembly which is configured to produce the desired basic aerodynamic shaped structure, said first face sheet having means to align said first face sheet in said die assembly; c. placing at least one metallic self-stable internal stiffener upon said first face sheet, said internal stiffener having a sufficient thickness to provide an adequate bonding area for joining the stiffener to the face sheets, a configuration which allows said self-stable member to provide sufficient support during the subsequent joining of said self-stable member to said face sheets, and a predetermined excess volume of material in its height dimension, and aligning said stiffener with respect to said first face sheet; d. placing said second face sheet in said die assembly over said internal stiffener, said second face sheet having means to align said second face sheet in said die; e. applying a forming and joining force to said internally stiffened structure for a sufficient duration at sufficient elevated temperature to cause intimate contact between opposed longitudinal edges of said face sheets and between said self-stable stiffener and adjacent areas of said face sheets by plastic flowing the predetermined excess volumes of material in the height of said self-stable internal stiffener and along the longitudinal edges of said face sheets so as to join and bond said self-stable stiffener by diffusion bonding to said face sheets and to join and bond said opposed longitudinal edges, said excess volume of flow material causing increased solidity, thereby producing an aerodynamically shaped structure with leading and trailing edges, said forming and joining force being substantially localized in the to-be-joined areas and determined by the amount of excess material to be flowed and the plastic flow characteristics of the metal used.
Claim 15
Dependent Claim
17 words
The method of claim 12 including forming said reduced thickness of said face sheets by chemical milling.
Claim 16
Dependent Claim
18 words
The method of claim 12 including forming said reduced thickness of said face sheets by electrical discharge machining.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-08-22 | 1981-02-21 | 1981-08-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-08-22 | 1985-02-21 | 1985-08-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-08-22 | 1989-02-21 | 1989-08-23 | $7700.00 | Window Closed / Lapsed |