US4882823A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Superplastic forming diffusion bonding process
Assignee: Fifth Third Bank Indiana
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Filing: 1988-01-27
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Granted: 1989-11-28
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Expires: 2008-01-27
Abstract
Abstract A method is set forth of forming a hollow structure having a varying mass distribution. Two sheets of a diffusion bondable and superplastic formable material are formed with one flat surface and an opposite surface contoured to have a selected mass distribution. A stop-off material is applied between selected non-peripheral portions of each of the flat surfaces whereat diffusion bonding is to be prevented and superplastic forming is to be required. An intermediate flat core sheet may also be present. The flat surfaces are positioned in abutting relation to each other or to the intermediate flat core sheet. The sheets are subjected to diffusion bonding conditions. The sheets are superplastically formed to expand them apart against a die. The invention also provides a method of preinflating contoured sheets prior to superplastically forming them to avoid truss core rupture. Hollow aircraft engine components are formed by the methods.
Inventors
- 👤 Edward D. Weisert
- 👤 John R. Fischer
- 👤 William L. McCauley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 10:33
CPC Classifications
B; B21; B21D; B21D26/00; B21D26/02; B21D26/053; B21D26/055; B23; B23K; B23K20/00; B23K20/18; Y; Y10; Y10T; Y10T29/00; Y10T29/18; Y10T29/49; Y10T29/49316; Y10T29/49336; Y10T29/49339; Y10T29/49805
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
225 words
A method of forming a hollow structure having a varying mass distribution, comprising: forming a first unitary sheet of a diffusion bondable and superplastically formable material with one flat surface and an opposite surface contoured to have a first selected non-uniform mass distribution; forming a second sheet of a superplastically formable material that is diffusion bondable to said first sheet with one flat surface and an opposite surface contoured to have a second selected mass distribution, said first and second mass distributions being such as to provide said varying mass distribution for said hollow structure; positioning each of said flat surfaces in abutting relation to a respective one of one another and a respective one of a pair of oppositely facing flat surfaces of an intermediate flat core sheet formed of a material that is diffusion bondable to said first and second sheets and with a stop-off material between selected non-peripheral portions of each of abutting said flat surfaces whereat diffusion bonding is to be prevented and superplastic forming is to be required; subjecting said sheets to diffusion bonding conditions to thereby bond said flat surfaces to one another or to said core sheet other than where said stop-off material was applied to form a diffusion bonded sandwich; and subjecting said sheets to superplastic forming conditions and thereby expanding said sheets apart against a die.
Claim 2
Independent Claim
225 words
A method of forming a hollow structure having a varying mass distribution, comprising: forming a first unitary sheet of a diffusion bondable and superplastically formable material with one flat surface and an opposite surface contoured to have a first selected non-uniform mass distribution; forming a second sheet of a superplastically formable material that is diffusion bondable to said first sheet with one flat surface and an opposite surface contoured to have a second selected mass distribution, said first and second mass distributions being such as to provide said varying mass distribution for said hollow structure; positioning each of said flat surfaces in abutting relation to a respective one of one another and a respective one of a pair of oppositely facing flat surfaces of an intermediate flat core sheet formed of a material that is diffusion bondable to said first and second sheets and with a stop-off material between selected non-peripheral portions of each of abutting said flat surfaces whereat diffusion bonding is to be prevented and superplastic forming is to be required; subjecting said sheets to diffusion bonding conditions to thereby bond said flat surfaces to one another or to said core sheet other than where said stop-off material was applied to form a diffusion bonded sandwich; and subjecting said sheets to superplastic forming conditions and thereby expanding said sheets apart against a die.
Claim 3
Dependent Claim
41 words
A method as set forth in claim 1, further including; forming at least one of said first and second sheets by hot forming said opposite surface thereof against a die and then machining said one surface thereof until it is flat.
Claim 4
Dependent Claim
46 words
A method as set forth in claim 1, further including: forming at least one of said first and second sheets from a relatively thick sheet having said one flat surface by maintaining said one surface thereof flat while machining said opposite surface thereof to contour it.
Claim 5
Dependent Claim
40 words
A method as set forth in claim 1, further including: forming at least one of said first and second sheets by hot forming said one surface against a mandrel and them machining said one surface thereof until it is flat.
Claim 6
Dependent Claim
53 words
A method as set forth in claim 1, further including: forming at least one of said first and second sheets from a relatively thick sheet having said one flat surface by maintaining said one surface thereof flat while chemically milling, electrochemically machining or electrically discharge machining said opposite surface thereof to contour it.
Claim 7
Dependent Claim
78 words
A method as set forth in claim 1, further including: forming a flat area on said contoured opposite surface of at least one of said first and second sheets prior to subjecting said sheets to diffusion bonding conditions; and abutting a flat surface of an additional structural member to said flat area, whereby said flat area is diffusion bonded to said flat surface of said additional structural member during said subjecting of said sheets to diffusion bonding conditions.
Claim 8
Dependent Claim
12 words
A hollow structure formed in accordance with the method of claim 6.
Claim 9
Dependent Claim
12 words
A hollow structure formed in accordance with the method of claim 1.
Claim 10
Dependent Claim
55 words
A method as set forth in claim 1, further including, prior to expanding said sheets apart against said die: preinflating said sandwich under superplastic forming conditions to expand said sandwich against a preinflation die to increase the average thickness of the diffusion bonded sandwich no more than about 150 mils and form a preinflated structure.
Claim 11
Dependent Claim
27 words
A method as set forth in claim 9 further including, following said preinflating and preceeding said second subjecting step; contouring said preinflated structure to a desired shape.
Claim 12
Independent Claim
268 words
A method of forming a hollow structure having a varying mass distribution, comprising: forming a first unitary sheet of a diffusion bondable and superplastically formable material with one flat surface and an opposite surface contoured to have a first selected non-uniform mass distribution; forming a second sheet of a superplastically formable material that is diffusion bondable to said first sheet with one flat surface and an opposite surface contoured to have a second selected mass distribution, said first and second mass distributions being such as to provide said varying mass distribution for said hollow structure; positioning each of said flat surfaces in abutting relation to a respective one of one another and a respective one of a pair of oppositely facing flat surfaces of an intermediate flat core sheet, formed of a material that is diffusion bondable to said first and second sheets and with a stop-off material between selected non-peripheral portions of each of said abutting flat surfaces whereat diffusion bonding is to be prevented and superplastic forming is to be required; subjecting said sheets to diffusion bonding conditions to thereby bond said flat surfaces to one another or to said core sheet other than where said stop-off material was applied to form a diffusion bonded sandwich; preinflating said sandwich under superplastic forming conditions to expand said sandwich against a first die to increase the average thickness of the diffusion bonded sandwich no more than about 150 mils and form a preinflated structure; and thereafter subjecting said preinflated structure to superplastic forming conditions and thereby expanding said sheets apart against a second die to a desired extent.
Claim 13
Independent Claim
268 words
A method of forming a hollow structure having a varying mass distribution, comprising: forming a first unitary sheet of a diffusion bondable and superplastically formable material with one flat surface and an opposite surface contoured to have a first selected non-uniform mass distribution; forming a second sheet of a superplastically formable material that is diffusion bondable to said first sheet with one flat surface and an opposite surface contoured to have a second selected mass distribution, said first and second mass distributions being such as to provide said varying mass distribution for said hollow structure; positioning each of said flat surfaces in abutting relation to a respective one of one another and a respective one of a pair of oppositely facing flat surfaces of an intermediate flat core sheet, formed of a material that is diffusion bondable to said first and second sheets and with a stop-off material between selected non-peripheral portions of each of said abutting flat surfaces whereat diffusion bonding is to be prevented and superplastic forming is to be required; subjecting said sheets to diffusion bonding conditions to thereby bond said flat surfaces to one another or to said core sheet other than where said stop-off material was applied to form a diffusion bonded sandwich; preinflating said sandwich under superplastic forming conditions to expand said sandwich against a first die to increase the average thickness of the diffusion bonded sandwich no more than about 150 mils and form a preinflated structure; and thereafter subjecting said preinflated structure to superplastic forming conditions and thereby expanding said sheets apart against a second die to a desired extent.
Claim 14
Dependent Claim
27 words
A method as set forth in claim 11, further including, following said preinflating and preceeding said second subjecting step: contouring said preinflated structure to a desired shape.
Claim 15
Dependent Claim
41 words
A method as set forth in claim 11, further including; forming at least one of said first and second sheets by hot forming said opposite surface thereof against a die and then machining said one surface thereof until it is flat.
Claim 16
Dependent Claim
46 words
A method as set forth in claim 11, further including: forming at least one of said first and second sheets from a relatively thick sheet having said one flat surface by maintaining said one surface thereof flat while machining said opposite surface thereof, to contour it.
Claim 17
Dependent Claim
40 words
A method as set forth in claim 11, further including: forming at least one of said first and second sheets by hot forming said one surface against a mandrel and then machining said one surface thereof until it is flat.
Claim 18
Dependent Claim
53 words
A method as set forth in claim 11, further including: forming at least one of said first and second sheets from a relatively thick sheet having said one flat surface by maintaining said one surface thereof flat while chemically milling, electrochemically machining or electrically discharge machining said opposite surface thereof to contour it.
Claim 19
Dependent Claim
78 words
A method as set forth in claim 11, further including: forming a flat area on said contoured opposite surface of at least one of said first and second sheets prior to subjecting said sheets to diffusion bonding conditions; and abutting a flat surface of an additional structural member to said flat area, whereby said flat area is diffusion bonded to said flat surface of said additional structural member during said subjecting of said sheets to diffusion bonding conditions.
Claim 20
Dependent Claim
12 words
A hollow structure formed in accordance with the method of claim 17.
Claim 21
Dependent Claim
12 words
A hollow structure formed in accordance with the method of claim 11.
Claim 22
Independent Claim
181 words
A method of forming a hollow structure having a varying mass distribution, comprising: forming a first unitary sheet of a diffusion bondable and superplastically formable material with one flat surface and an opposite surface contoured to have a first selected non-uniform mass distribution; forming a second sheet of a superplastically formable material that is diffusion bondable to said first sheet with one flat surface and an opposite surface contoured to have a second selected mass distribution, said first and second mass distributions being such as to provide said varying mass distribution for said hollow structure; positioning said flat surfaces in abutting relation to one another with a stop-off material between selected non-peripheral portions of each of said abutting flat surfaces whereat diffusion bonding is to be prevented and superplastic forming is to be required; subjecting said sheets to diffusion bonding conditions to thereby bond said flat surfaces to one another other than where said stop-off material was applied to form a diffusion bonded sandwich; and subjecting said sheets to superplastic forming conditions and thereby expanding said sheets apart against a die.
Claim 23
Independent Claim
181 words
A method of forming a hollow structure having a varying mass distribution, comprising: forming a first unitary sheet of a diffusion bondable and superplastically formable material with one flat surface and an opposite surface contoured to have a first selected non-uniform mass distribution; forming a second sheet of a superplastically formable material that is diffusion bondable to said first sheet with one flat surface and an opposite surface contoured to have a second selected mass distribution, said first and second mass distributions being such as to provide said varying mass distribution for said hollow structure; positioning said flat surfaces in abutting relation to one another with a stop-off material between selected non-peripheral portions of each of said abutting flat surfaces whereat diffusion bonding is to be prevented and superplastic forming is to be required; subjecting said sheets to diffusion bonding conditions to thereby bond said flat surfaces to one another other than where said stop-off material was applied to form a diffusion bonded sandwich; and subjecting said sheets to superplastic forming conditions and thereby expanding said sheets apart against a die.
References Cited (Backward Citations)
US2766514A
Cited
US4292375A
Cited
US4526312A
Cited
US4331284A
Cited
US4406393A
Cited
US4483478A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-11-27 | 1993-05-29 | 1993-11-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-11-27 | 1997-05-29 | 1997-11-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-11-27 | 2001-05-29 | 2001-11-28 | $7700.00 | Window Closed / Lapsed |