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US4758286A
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Heat treated and aged Al-base alloys containing lithium, magnesium and copper and process
Assignee: Cegedur Societe de Transformation de lAluminium Pechiney SA
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Filing: 1984-11-22
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Granted: 1988-07-19
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Expires: 2004-11-22
Abstract
Abstract The present invention relates to Al-base alloys essentially containing additions of Li, Mg and Cu and possibly minor additions of Cr, Zr, Ti and Mn, which have high specific mechanical characteristics, a low density and good resistance to corrosion. The alloys according to the invention contain (in % by weight): Li 1.8 to 3.5; Mg 1.4 to 6.0; Cu 0.2 to 1.6 with Mg/Cu≧1.5; Cr up to 0.3; Mn up to 1; Zr up to 0.2; Ti up to 0.1 and/or Be up to 0.02, Fe up to 0.20; Si up to 0.12; Zn up to 0.35%. The homogenization and solution treatments must be taken to a sufficiently advanced stage to dissolve the quaternary intermetallic phases (Al, Li, Mg, Cu) which are larger than 5 μm in size. Such alloys present a compromise between their mechanical characteristics and their density, which is higher than that of the knwn Al Cu Mg alloys, and alloys containing Li.
Inventors
- 👤 Bruno Dubost
- 👤 Philippe Meyer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 15:03
CPC Classifications
C; C22; C22C; C22C21/00; C22C21/06
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
82 words
A heat treated and aged Al-base alloy having high strength and high ductility consisting essentially of (in % by weight): ______________________________________
Li = 1.8 to 3.5
Mg = 1.4 to 6.0
with Mg/Cu ≧ 1.5
Cu = 0.2 to 1.6%
Fe ≦ 0.20
Si ≦ 0.12
Cr 0 to 0.3
Mn 0 to 1.0
Zr 0 to 0.2
Ti 0 to 0.1
Be 0 to 0.02
Zn 0 to 0.35
other elements (impurities)
each < 0.05
total < 0.15
balance: aluminium.
______________________________________
Claim 2
Dependent Claim
82 words
A heat treated and aged Al-base alloy having high strength and high ductility consisting essentially of (in % by weight): ______________________________________
Li = 1.8 to 3.5
Mg = 1.4 to 6.0
with Mg/Cu ≧ 1.5
Cu = 0.2 to 1.6%
Fe ≦ 0.20
Si ≦ 0.12
Cr 0 to 0.3
Mn 0 to 1.0
Zr 0 to 0.2
Ti 0 to 0.1
Be 0 to 0.02
Zn 0 to 0.35
other elements (impurities)
each < 0.05
total < 0.15
balance: aluminium.
______________________________________
Claim 3
Dependent Claim
15 words
Alloy according to claim 1 characterised in that it contains from 2.3 to 3.3% Li.
Claim 4
Dependent Claim
15 words
Alloy according to claim 1 characterised in that it contains from 0.25 to 1.2% Cu.
Claim 5
Dependent Claim
15 words
Alloy according to claim 1 characterised in that it contains from 1.4 to 5% Mg.
Claim 6
Dependent Claim
28 words
Alloy according to one of claims 1 to 4 characterised in that it contains from 2.3 to 3.3% Li, 0.25 to 1.2% Cu and 1.4 to 5% Mg.
Claim 7
Dependent Claim
11 words
Alloy according to claim 1 characterised in that: %Li(%Cu+2)+%Mg=K with 8.5≦K≦11.5.
Claim 8
Dependent Claim
9 words
Alloy according to claim 6 characterised in that 9≦K≦11.
Claim 9
Dependent Claim
51 words
A process for the heat treatment of the alloys according to claim 1 comprising a homogenization operation, a solution treatment, a quenching operation and a tempering operation, characterised in that the alloy is subjected to homogenization and solution treatment at a temperature (in °C.) of the order of θ=535-5 (% Mg).
Claim 10
Dependent Claim
43 words
A process according to claim 8 characterised in that the duration of the homogenization operation and the solution treatment is sufficiently long that, after the quenching operation, the residual quaternary intermetallic phases (Al, Li, Mg, Cu) are less than 5 μm in size.
Claim 11
Dependent Claim
31 words
A process according to claim 8 or claim 9 characterised in that the homogenization operation is carried out in the temperature range which is defined by θ+10 (°C.) and θ-20 (°C.).
Claim 12
Dependent Claim
29 words
A process according to claim 8 or claim 9 characterised in that the solution treatment is carried out in the temperature range defined by θ+10 (°C.) and θ-10 (°C.).
Claim 13
Dependent Claim
32 words
A process according to claim 8 or claim 9 characterised in that the tempering operation is effected at from 170° to 220° C. for a period ranging from 8 to 48 hours.
Claim 14
Dependent Claim
31 words
A process according to claim 8 or claim 9 characterised in that plastic deformation of from 1 to 5% is applied to the treated product between the quenching and tempering operations.
Claim 15
Dependent Claim
15 words
A process according to claim 13, wherein said plastic deformation is from 2 to 4%.
References Cited (Backward Citations)
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1991-07-19 | 1992-01-18 | 1992-07-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-07-19 | 1996-01-18 | 1996-07-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-07-19 | 2000-01-18 | 2000-07-19 | $7700.00 | Window Closed / Lapsed |