US4890784A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for diffusion bonding aluminum
Assignee: Boeing North American Inc
•
Filing: 1983-03-28
•
Granted: 1990-01-02
•
Expires: 2003-03-28
Abstract
Abstract Diffusion bonding of aluminum alloys is performed using a thin alloy interlayer placed between mating surfaces of the alloy members to be bonded, the interlayer having a specific composition which is dependent upon the composition of the alloy members, the diffusion bonding temperature, the interdiffusion rates of the alloy members compared with the interlayer, and the solid state diffusion rate of the interlayer into the alloy members. The process is preferably further characterized by isothermal solidification of the interlayer after the diffusion bonding temperature has been reached.
Inventors
- 👤 Clifford C. Bampton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 17:53
CPC Classifications
B; B23; B23K; B23K35/00; B23K35/22; B23K35/24; B23K35/28; B23K35/286; B23K35/001; B23K35/002
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
249 words
A method of diffusion bonding which comprises: providing two aluminum alloy members to be diffusion bonded within a temperature range suitable for solid state diffusion bonding, said aluminum alloy members each having at least one alloy additive therein; providing an interlayer of alloy which comprises aluminum and an alloy additive which is also in said alloy members, the percentage of said aluminum in said interlayer being less than the percentage of said aluminum in said alloy members, the percentage of said additive being large enough to assure that said interlayer will be at least partially liquid within said diffusion bonding temperature range for said alloy members, said interlayer having a surface oxide layer, said interlayer having a melting point below said temperature range, said alloy of said members being soluble in said interlayer when said interlayer is in a liquid phase; positioning said alloy members and said interlayer in an assembly such that said interlayer is sandwiched between the surfaces of said alloy members to be bonded; heating said assembly to within said temperature range such that said interlayer is transformed into a liquid phase and said surface oxide layer disrupted; and maintaining said assembly within said temperature range such that portions of said aluminum alloy members dissolve into said interlayer at a faster rate than said interlayer diffuses into said members, said interlayer eventually solidifies between said alloy members primarily due to its resulting increased aluminum content, said diffusion bonding of said alloy members and said interlayer occurs.
Claim 2
Independent Claim
249 words
A method of diffusion bonding which comprises: providing two aluminum alloy members to be diffusion bonded within a temperature range suitable for solid state diffusion bonding, said aluminum alloy members each having at least one alloy additive therein; providing an interlayer of alloy which comprises aluminum and an alloy additive which is also in said alloy members, the percentage of said aluminum in said interlayer being less than the percentage of said aluminum in said alloy members, the percentage of said additive being large enough to assure that said interlayer will be at least partially liquid within said diffusion bonding temperature range for said alloy members, said interlayer having a surface oxide layer, said interlayer having a melting point below said temperature range, said alloy of said members being soluble in said interlayer when said interlayer is in a liquid phase; positioning said alloy members and said interlayer in an assembly such that said interlayer is sandwiched between the surfaces of said alloy members to be bonded; heating said assembly to within said temperature range such that said interlayer is transformed into a liquid phase and said surface oxide layer disrupted; and maintaining said assembly within said temperature range such that portions of said aluminum alloy members dissolve into said interlayer at a faster rate than said interlayer diffuses into said members, said interlayer eventually solidifies between said alloy members primarily due to its resulting increased aluminum content, said diffusion bonding of said alloy members and said interlayer occurs.
Claim 3
Dependent Claim
17 words
The method of claim 1 where said maintaining step is such that said interlayer solidifies substantially isothermally.
Claim 4
Dependent Claim
18 words
The method of diffusion bonding as recited in claim 2 wherein said interlayer is essentially an aluminum-magnesium alloy.
Claim 5
Dependent Claim
21 words
The method of diffusion bonding as recited in claim 3, wherein said interlayer has a thickness of less than ten micrometers.
Claim 6
Dependent Claim
32 words
The method of diffusion bonding as recited in claim 4 further comprising removing an oxide layer from the surfaces of the alloy members to be joined prior to placing the interlayer therebetween.
Claim 7
Dependent Claim
29 words
The method of claim 5 wherein the liquidus line for the interlayer alloy rises at a rate of at least 5° C. per increase in weight percent of aluminum.
Claim 8
Dependent Claim
29 words
The method of claim 4 wherein the liquidus line for the interlayer alloy rises at a rate of at least 5° C. per increase in weight percent of aluminum.
Claim 9
Dependent Claim
32 words
The method of diffusion bonding as recited in claim 3 further comprising removing an oxide layer from the surfaces of the alloy members to be joined prior to placing the interlayer therebetween.
Claim 10
Dependent Claim
29 words
The method of claim 8 wherein the liquidus line for the interlayer alloy rises at a rate of at least 5° C. per increase in weight percent of aluminum.
Claim 11
Dependent Claim
29 words
The method of claim 3 wherein the liquidus line for the interlayer alloy rises at a rate of at least 5° C. per increase in weight percent of aluminum.
Claim 12
Dependent Claim
27 words
The method of diffusion bonding as recited in claim 1 wherein the melting point of said interlayer increases as said aluminum alloy members dissolve into said interlayer.
Claim 13
Dependent Claim
25 words
The method of claim 1 wherein the melting point of said interlayer is at least 20° C. below the lowest temperature of said temperature range.
Claim 14
Dependent Claim
29 words
The method of claim 12 wherein the liquidus line for the interlayer alloy rises at a rate of at least 5° C. per increase in weight percent of aluminum.
Claim 15
Dependent Claim
29 words
The method of claim 1 wherein the liquidus line for the interlayer alloy rises at a rate of at least 5° C. per increase in weight percent of aluminum.
Claim 16
Dependent Claim
29 words
The method of claim 2 wherein the liquidus line for the interlayer alloy rises at a rate of at least 5° C. per increase in weight percent of aluminum.
Claim 17
Dependent Claim
44 words
A method of diffusion bonding as recited in claim 1 wherein said maintaining step is continued to allow said interlayer to diffuse into said aluminum alloy members after solidification of said interlayer such that a homogeneous diffusion bond between said aluminum alloy members results.
Claim 18
Dependent Claim
25 words
The method of claim 16 wherein the melting point of said interlayer is at least 20° C. below the lowest temperature of said temperature range.
Claim 19
Dependent Claim
29 words
The method of claim 16 wherein the liquidus line for the interlayer alloy rises at a rate of at least 5° C. per increase in weight percent of aluminum.
Claim 20
Dependent Claim
24 words
The method of claim 16 wherein said additive of said interlayer has a high solid state diffusity in the alloy of said alloy members.
Claim 21
Dependent Claim
24 words
The method of claim 1 wherein said additive of said interlayer has a high solid state diffusity in the alloy of said alloy members.
Claim 22
Dependent Claim
21 words
The method of diffusion bonding as recited in claim 1 wherein said alloy of said members is a fine grain alloy.
Claim 23
Dependent Claim
22 words
The method of diffusion bonding as recited in claim 1 wherein said alloy additive of said interlayer is magnesium, copper, or zinc.
Claim 24
Dependent Claim
22 words
The method of diffusion bonding as recited in claim 1 wherein said surface layer has a thickness of less than ten micrometers.
Claim 25
Dependent Claim
21 words
The method of diffusion bonding as recited in claim 1 wherein said diffusion bonding temperature is between 482° to 535° C.
Claim 26
Dependent Claim
18 words
The method of diffusion bonding as recited in claim 1 wherein said interlayer is essentially an aluminum-magnesium alloy.
Claim 27
Dependent Claim
32 words
The method of diffusion bonding as recited in claim 1 further comprising removing an oxide layer from the surfaces of the alloy members to be joined prior to placing the interlayer therebetween.
References Cited (Backward Citations)
US2095807A
Cited
US3180022A
Cited
US3373482A
Cited
US3339269A
Cited
US3373483A
Cited
US3581382A
Cited
US3678570A
Cited
US3993238A
Cited
US3937387A
Cited
US4046305A
Cited
US3935986A
Cited
US4005988A
Cited
US4122992A
Cited
US4174232A
Cited
US4240574A
Cited
US4331286A
Cited
US4222797A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-01-01 | 1993-07-03 | 1994-01-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-01-01 | 1997-07-03 | 1998-01-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-01-01 | 2001-07-03 | 2002-01-02 | $7700.00 | Window Closed / Lapsed |