CA3096776A1 - Aluminium-copper-lithium alloy having improved compressive strength and improved toughness - Google Patents
Aluminium-copper-lithium alloy having improved compressive strength and improved toughness Download PDFInfo
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- 229910052782 aluminium Inorganic materials 0.000 title claims abstract description 13
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 title claims abstract description 13
- 239000004411 aluminium Substances 0.000 title abstract 2
- 229910052744 lithium Inorganic materials 0.000 title description 13
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 title description 12
- 230000006835 compression Effects 0.000 title description 11
- 238000007906 compression Methods 0.000 title description 11
- 229910000838 Al alloy Inorganic materials 0.000 claims abstract description 19
- 238000000034 method Methods 0.000 claims abstract description 12
- 229910052719 titanium Inorganic materials 0.000 claims abstract description 12
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 11
- 229910052748 manganese Inorganic materials 0.000 claims abstract description 9
- 229910052720 vanadium Inorganic materials 0.000 claims abstract description 9
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 6
- 230000032683 aging Effects 0.000 claims description 20
- 238000004519 manufacturing process Methods 0.000 claims description 16
- 230000035882 stress Effects 0.000 claims description 16
- 229910052709 silver Inorganic materials 0.000 claims description 12
- 229910052725 zinc Inorganic materials 0.000 claims description 10
- 229910052749 magnesium Inorganic materials 0.000 claims description 9
- 229910001338 liquidmetal Inorganic materials 0.000 claims description 6
- 239000010455 vermiculite Substances 0.000 claims description 6
- 238000005096 rolling process Methods 0.000 claims description 4
- 239000002245 particle Substances 0.000 claims description 3
- 229910045601 alloy Inorganic materials 0.000 description 41
- 239000000956 alloy Substances 0.000 description 41
- 239000011777 magnesium Substances 0.000 description 24
- 239000011701 zinc Substances 0.000 description 23
- 239000010949 copper Substances 0.000 description 20
- 239000010936 titanium Substances 0.000 description 20
- 239000011572 manganese Substances 0.000 description 19
- 239000000203 mixture Substances 0.000 description 15
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 14
- 230000003068 static effect Effects 0.000 description 9
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 8
- 229910052802 copper Inorganic materials 0.000 description 8
- 239000004332 silver Substances 0.000 description 8
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 7
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 6
- 238000000265 homogenisation Methods 0.000 description 6
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 5
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 4
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 4
- 229910052742 iron Inorganic materials 0.000 description 4
- 239000001989 lithium alloy Substances 0.000 description 4
- 238000007670 refining Methods 0.000 description 4
- 239000010703 silicon Substances 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- 239000002970 Calcium lactobionate Substances 0.000 description 3
- 229910000733 Li alloy Inorganic materials 0.000 description 3
- -1 aluminum-copper-lithium Chemical compound 0.000 description 3
- 238000005266 casting Methods 0.000 description 3
- 230000015556 catabolic process Effects 0.000 description 3
- 238000010276 construction Methods 0.000 description 3
- 238000006731 degradation reaction Methods 0.000 description 3
- 229910052735 hafnium Inorganic materials 0.000 description 3
- 238000005098 hot rolling Methods 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 239000010944 silver (metal) Substances 0.000 description 3
- 238000005482 strain hardening Methods 0.000 description 3
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 238000001125 extrusion Methods 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 238000010791 quenching Methods 0.000 description 2
- 230000000171 quenching effect Effects 0.000 description 2
- 229910052706 scandium Inorganic materials 0.000 description 2
- 239000003351 stiffener Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 229910017539 Cu-Li Inorganic materials 0.000 description 1
- 241001122767 Theaceae Species 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- AZDRQVAHHNSJOQ-UHFFFAOYSA-N alumane Chemical class [AlH3] AZDRQVAHHNSJOQ-UHFFFAOYSA-N 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 230000001627 detrimental effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 235000012438 extruded product Nutrition 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 239000010931 gold Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 229910052761 rare earth metal Inorganic materials 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 239000003381 stabilizer Substances 0.000 description 1
- 238000009864 tensile test Methods 0.000 description 1
- 229910052726 zirconium Inorganic materials 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C21/00—Alloys based on aluminium
- C22C21/12—Alloys based on aluminium with copper as the next major constituent
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
- C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
- C22F1/04—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of aluminium or alloys based thereon
- C22F1/057—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of aluminium or alloys based thereon of alloys with copper as the next major constituent
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C21/00—Alloys based on aluminium
- C22C21/12—Alloys based on aluminium with copper as the next major constituent
- C22C21/14—Alloys based on aluminium with copper as the next major constituent with silicon
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C21/00—Alloys based on aluminium
- C22C21/12—Alloys based on aluminium with copper as the next major constituent
- C22C21/16—Alloys based on aluminium with copper as the next major constituent with magnesium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C21/00—Alloys based on aluminium
- C22C21/12—Alloys based on aluminium with copper as the next major constituent
- C22C21/18—Alloys based on aluminium with copper as the next major constituent with zinc
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Powder Metallurgy (AREA)
- Conductive Materials (AREA)
Abstract
L'invention concerne un produit à base d'alliage d'aluminium comprenant, en pourcentage en poids, 4,0 à 4,6% en poids de Cu, 0,7 à 1,2% en poids de Li, 0,5 à 0,65 % en poids de Mg, 0,10 à 0,20% en poids de Zr, 0,15 à 0,30% en poids d'Ag, 0,25 à 0,45% en poids de Zn, 0,05à 0,35% en poids de Mn, au plus 0,20 % en poids de Fe + Si, au moins un élément choisi parmi Cr, Sc, Hf, V et Ti, la quantité dudit élément, s'il est choisi, étant de 0,05 à 0,3% en poids pour Cr et pour Sc, 0,05 à 0,5% en poids pour Hf et pour V et de 0,01 à 0,15% en poids pour Ti, autres éléments au plus 0,05% en poids chacun et 0,15% en poids au total et reste aluminium. L'invention concerne également un procédé pour l'obtention d'un tel produit et son utilisation en tant qu'élément de structure d'avion.
Description
STRENGTH AND IMPROVED TOUGHNESS
Field of the invention The invention relates to products made of aluminum-copper-lithium alloys, more particularly, such products intended for aeronautical and aerospace construction.
Prior art Aluminum alloy products are developed to produce high strength parts intended in particular for the aircraft industry and the aerospace industry.
Aluminum alloys containing lithium are of great interest in this regard, as lithium can reduce the density of aluminum by 3% and increase the modulus of elasticity by 6% for each weight percent lithium added. For these alloys to be selected in aircrafts, their performance in relation to other properties of use must reach that of commonly used alloys, in particular in terms of compromise between the properties of static mechanical strength (tensile and compressive yield strength, ultimate tensile strength) and damage tolerance properties (toughness, resistance to the fatigue crack propagation), these properties being generally mutually exclusive. For some parts such as the upper wing skin, the compressive yield strength is an essential property. These mechanical properties should moreover preferably be stable over time and have good thermal stability, that is to say not be significantly modified by aging at operating temperature.
These alloys must also have sufficient corrosion resistance, be able to be shaped according to the usual methods and have low residual stresses so that they can be fully machined.
Finally, they must be able to be obtained by robust manufacturing methods, in particular, the Date Reçue/Date Received 2020-10-09
Field of the invention The invention relates to products made of aluminum-copper-lithium alloys, more particularly, such products intended for aeronautical and aerospace construction.
Prior art Aluminum alloy products are developed to produce high strength parts intended in particular for the aircraft industry and the aerospace industry.
Aluminum alloys containing lithium are of great interest in this regard, as lithium can reduce the density of aluminum by 3% and increase the modulus of elasticity by 6% for each weight percent lithium added. For these alloys to be selected in aircrafts, their performance in relation to other properties of use must reach that of commonly used alloys, in particular in terms of compromise between the properties of static mechanical strength (tensile and compressive yield strength, ultimate tensile strength) and damage tolerance properties (toughness, resistance to the fatigue crack propagation), these properties being generally mutually exclusive. For some parts such as the upper wing skin, the compressive yield strength is an essential property. These mechanical properties should moreover preferably be stable over time and have good thermal stability, that is to say not be significantly modified by aging at operating temperature.
These alloys must also have sufficient corrosion resistance, be able to be shaped according to the usual methods and have low residual stresses so that they can be fully machined.
Finally, they must be able to be obtained by robust manufacturing methods, in particular, the Date Reçue/Date Received 2020-10-09
2 properties must be able to be obtained on industrial tools for which it is difficult to guarantee temperature homogeneity within a few degrees for large parts.
Patent US 5,032,359 describes a large family of aluminum-copper-lithium alloys wherein the addition of magnesium and silver, in particular between 0.3 and 0.5 percent by weight, allows to increase the mechanical strength.
Patent US 5,455,003 describes a method for manufacturing Al-Cu-Li alloys which have improved mechanical strength and improved toughness at cryogenic temperature, in particular thanks to suitable work hardening and ageing. This patent recommends in particular the composition, in percentage by weight, Cu = 3.0 - 4.5, Li = 0.7 -1.1, Ag = 0 -0.6, Mg = 0.3 - 0.6 and Zn = 0 - 0.75.
Patent US 7,438,772 describes alloys comprising, in weight percentage, Cu: 3-5, Mg: 0.5-2, Li: 0.01-0.9 and discourages the use of higher lithium content due to degradation of the compromise between toughness and mechanical strength.
Patent US 7,229,509 describes an alloy comprising (% by weight): (2.5-5.5) Cu, (0.1-2.5) Li, (0.2-1.0) Mg, (0.2-0.8) Ag, (0.2-0.8) Mn, 0.4 max Zr or other grain refiner agents such as Cr, Ti, Hf, Sc, V.
Patent application US 2009/142222 Al describes alloys comprising (in % by weight), 3.4 to 4.2% of Cu, 0.9 to 1.4% of Li, 0.3 to 0.7% of Ag, 0.1 to 0.6% of Mg, 0.2 to 0.8% of Zn, 0.1 to 0.6% of Mn and 0.01 to 0.6% of at least one element for controlling the granular structure.
This application also describes a method for manufacturing extruded products.
Patent application W02009/036953 relates to an aluminum alloy product for structural elements having a chemical composition comprising, by weight Cu from 3.4 to 5.0, Li from 0.9 to 1.7, Mg from 0.2 to 0.8, Ag from about 0.1 to 0.8, Mn from 0.1 to 0.9, Zn up to 1.5, and one or more elements selected from the group consisting of: (Zr about 0.05 to 0.3, Cr 0.05 to 0.3, Ti about 0.03 to 0.3, Sc about 0.05 to 0.4, Hf about 0.05 to 0.4), Fe <0.15, Si <0.5, normal and unavoidable impurities.
Date Reçue/Date Received 2020-10-09
Patent US 5,032,359 describes a large family of aluminum-copper-lithium alloys wherein the addition of magnesium and silver, in particular between 0.3 and 0.5 percent by weight, allows to increase the mechanical strength.
Patent US 5,455,003 describes a method for manufacturing Al-Cu-Li alloys which have improved mechanical strength and improved toughness at cryogenic temperature, in particular thanks to suitable work hardening and ageing. This patent recommends in particular the composition, in percentage by weight, Cu = 3.0 - 4.5, Li = 0.7 -1.1, Ag = 0 -0.6, Mg = 0.3 - 0.6 and Zn = 0 - 0.75.
Patent US 7,438,772 describes alloys comprising, in weight percentage, Cu: 3-5, Mg: 0.5-2, Li: 0.01-0.9 and discourages the use of higher lithium content due to degradation of the compromise between toughness and mechanical strength.
Patent US 7,229,509 describes an alloy comprising (% by weight): (2.5-5.5) Cu, (0.1-2.5) Li, (0.2-1.0) Mg, (0.2-0.8) Ag, (0.2-0.8) Mn, 0.4 max Zr or other grain refiner agents such as Cr, Ti, Hf, Sc, V.
Patent application US 2009/142222 Al describes alloys comprising (in % by weight), 3.4 to 4.2% of Cu, 0.9 to 1.4% of Li, 0.3 to 0.7% of Ag, 0.1 to 0.6% of Mg, 0.2 to 0.8% of Zn, 0.1 to 0.6% of Mn and 0.01 to 0.6% of at least one element for controlling the granular structure.
This application also describes a method for manufacturing extruded products.
Patent application W02009/036953 relates to an aluminum alloy product for structural elements having a chemical composition comprising, by weight Cu from 3.4 to 5.0, Li from 0.9 to 1.7, Mg from 0.2 to 0.8, Ag from about 0.1 to 0.8, Mn from 0.1 to 0.9, Zn up to 1.5, and one or more elements selected from the group consisting of: (Zr about 0.05 to 0.3, Cr 0.05 to 0.3, Ti about 0.03 to 0.3, Sc about 0.05 to 0.4, Hf about 0.05 to 0.4), Fe <0.15, Si <0.5, normal and unavoidable impurities.
Date Reçue/Date Received 2020-10-09
3 Patent application WO 2012/085359 A2 relates to a method for manufacturing rolled products made of an aluminum-based alloy comprising 4.2 to 4.6% by weight of Cu, 0.8 to 1.30% by weight of Li , 0.3 to 0.8% by weight of Mg, 0.05 to 0.18% by weight of Zr, 0.05 to 0.4% by weight of Ag, 0.0 to 0.5% by weight of Mn, at most 0.20% by weight of Fe + Si, less thon 0.20% by weight of Zn, of least one element selected from Cr, Se, Hf and Ti, the amount of said element, if selected, being 0.05 to 0.3% by weight for Cr and for Se, 0.05 to 0.5% by weight for Hf and from 0.01 to 0.15% by weight for Ti, the other elements at most 0.05% by weight each and 0.15% by weight in total, the remainder being aluminum, comprising the steps of preparation, casting, homogenization, rolling with a temperature greater than 400 C, solution heat-treating, quenching , tensioning between 2 and 3.5% and ageing.
Patent application U52012/0225271 Al relates to wrought products with a thickness of at least 12.7 mm containing from 3.00 to 3.80% by weight of Cu, from 0.05 to 0.35% by weight of Mg, from 0.975 to 1.385% by weight of Li, wherein -0.3 Mg - 0.15Cu +1.65 <
Li < -0.3 Mg-0.15Cu +1.85, from 0.05 to 0.50% by weight of at least one grain structure control element, wherein the grain structure control element is selected from the group consisting of Zr, Sc, Cr, V, Hf, other rare earth elements, and combinations thereof, up to 1.0% by weight of Zn, up to 1.0% by weight of Mn, up to 0.12% by weight of Si, up to 0.15% by weight of Fe, up to 0.15% by weight of Ti, up to 0.10% by weight of other elements with a total not exceeding 0.35% by weight.
Application WO 2013/169901 describes alloys comprising, in percentage by weight, 3.5 to
Patent application U52012/0225271 Al relates to wrought products with a thickness of at least 12.7 mm containing from 3.00 to 3.80% by weight of Cu, from 0.05 to 0.35% by weight of Mg, from 0.975 to 1.385% by weight of Li, wherein -0.3 Mg - 0.15Cu +1.65 <
Li < -0.3 Mg-0.15Cu +1.85, from 0.05 to 0.50% by weight of at least one grain structure control element, wherein the grain structure control element is selected from the group consisting of Zr, Sc, Cr, V, Hf, other rare earth elements, and combinations thereof, up to 1.0% by weight of Zn, up to 1.0% by weight of Mn, up to 0.12% by weight of Si, up to 0.15% by weight of Fe, up to 0.15% by weight of Ti, up to 0.10% by weight of other elements with a total not exceeding 0.35% by weight.
Application WO 2013/169901 describes alloys comprising, in percentage by weight, 3.5 to
4.4% of Cu, 0.65 to 1.15% of Li, 0.1 to 1.0% of Ag, 0.45 to 0.75% of Mg, 0.45 to 0.75% of Zn and 0.05 to 0.50% of at least one element for the control of granular structure. The alloys advantageously have a Zn to Mg ratio comprised between 0.60 and 1.67.
There is a need for aluminum-copper-lithium alloy products having improved properties compared to those of known products, in particular in ternis of compromise between the properties of static mechanical strength, in particular the tensile and compressive yield Date Reçue/Date Received 2020-10-09 strength and the properties of damage tolerance, in particular toughness, thermal stability, corrosion resistance and machinability, while having a low density.
In addition, there is a need for a method for manufacturing these products that is robust, reliable and economical.
Object of the invention A first object of the invention is a product based on an aluminum alloy comprising, in percentage by weight, 4.0 to 4.6% by weight of Cu, 0.7 to 1.2% by weight of Li , 0.5 to 0.65% by weight of Mg, 0.10 to 0.20% by weight of Zr, 0.15 to 0.30% by weight of Ag, 0.25 to 0.45% by weight of Zn, 0.05 to 0.35% by weight of Mn, at most 0.20% by weight of Fe +
Si, at least one element selected from Cr, Sc, Hf, V and Ti, the amount of said element, if selected, being 0.05 to 0.3% by weight for Cr and for Sc, 0.05 to 0.5% by weight for Hf and for V and from 0.01 to 0.15% by weight for Ti, other elements at most 0.05% by weight each and 0.15% by weight in total and the remainder being aluminum.
A second object of the invention is a method for manufacturing a product based on an aluminum alloy wherein, successively, a) a liquid metal bath based on aluminum is prepared comprising 4.0 to 4.6% by weight of Cu; 0.7 to 1.2% by weight of Li; 0.5 to 0.65% by weight of Mg; 0.10 to 0.20% by weight of Zr; 0.15 to 0.30% by weight of Ag; 0.25 to 0.45% by weight of Zn; 0.05 to 0.35% by weight of Mn; at most 0.20% by weight of Fe + Si; at least one element selected from Cr, Sc, Hf, V and Ti, the amount of said element, if selected, being from 0.05 to 0.3% by weight for Cr and for Sc, 0.05 to 0.5% by weight for Hf and for V and from 0.01 to 0.15% by weight for Ti; other elements at most 0.05% by weight each and 0.15% by weight in total and the remainder being aluminum;
b) a crude fonn is cast from said liquid metal bath;
c) said crude form is homogenized at a temperature comprised between 450 C and 550 C and preferably between 480 C and 530 C for a period comprised between
There is a need for aluminum-copper-lithium alloy products having improved properties compared to those of known products, in particular in ternis of compromise between the properties of static mechanical strength, in particular the tensile and compressive yield Date Reçue/Date Received 2020-10-09 strength and the properties of damage tolerance, in particular toughness, thermal stability, corrosion resistance and machinability, while having a low density.
In addition, there is a need for a method for manufacturing these products that is robust, reliable and economical.
Object of the invention A first object of the invention is a product based on an aluminum alloy comprising, in percentage by weight, 4.0 to 4.6% by weight of Cu, 0.7 to 1.2% by weight of Li , 0.5 to 0.65% by weight of Mg, 0.10 to 0.20% by weight of Zr, 0.15 to 0.30% by weight of Ag, 0.25 to 0.45% by weight of Zn, 0.05 to 0.35% by weight of Mn, at most 0.20% by weight of Fe +
Si, at least one element selected from Cr, Sc, Hf, V and Ti, the amount of said element, if selected, being 0.05 to 0.3% by weight for Cr and for Sc, 0.05 to 0.5% by weight for Hf and for V and from 0.01 to 0.15% by weight for Ti, other elements at most 0.05% by weight each and 0.15% by weight in total and the remainder being aluminum.
A second object of the invention is a method for manufacturing a product based on an aluminum alloy wherein, successively, a) a liquid metal bath based on aluminum is prepared comprising 4.0 to 4.6% by weight of Cu; 0.7 to 1.2% by weight of Li; 0.5 to 0.65% by weight of Mg; 0.10 to 0.20% by weight of Zr; 0.15 to 0.30% by weight of Ag; 0.25 to 0.45% by weight of Zn; 0.05 to 0.35% by weight of Mn; at most 0.20% by weight of Fe + Si; at least one element selected from Cr, Sc, Hf, V and Ti, the amount of said element, if selected, being from 0.05 to 0.3% by weight for Cr and for Sc, 0.05 to 0.5% by weight for Hf and for V and from 0.01 to 0.15% by weight for Ti; other elements at most 0.05% by weight each and 0.15% by weight in total and the remainder being aluminum;
b) a crude fonn is cast from said liquid metal bath;
c) said crude form is homogenized at a temperature comprised between 450 C and 550 C and preferably between 480 C and 530 C for a period comprised between
5 and 60 hours;
d) said homogenized crude form is hot-worked, preferably by rolling;
Date Reçue/Date Received 2020-10-09 e) the hot-worked product is solution heat-treated between 490 and 530 C for 15 min to 8 h and said solution heat-treated product is quenched;
f) said product is cold-worked with a working of 2 to 16%;
g) an ageing is carried out wherein said cold-worked product reaches a temperature comprised between 130 and 170 C and preferably between 140 and 160 C for 5 to 100 hours and preferably 10 to 70 hours.
Another object of the invention is an alloy product according to the invention or that can be obtained according to the method of the invention, with a thickness comprised between 8 and 50 mm having, at mid-thickness:
i) a compressive yield strength Rcp0.2(L) > 590 MPa, preferably Rcp0.2(L) >
595 MPa;
ii) a toughness Kapp (L-T) > 60 MPa-Vm, preferably Kapp (L-T) > 75 MPa-Vm, with Kapp (L-T) the value of the apparent stress intensity factor at rupture defined according to standard ASTM E561 (2015) measured on CCT test specimens of width W=406 mm and thickness B = 6.35 mm;
iii) a difference between the tensile yield strength Rpo.2(L) and the compressive yield strength Rcp0.2(L), Rpo.2(L) - Rcpo.2(L), less or equal to 10 MPa, preferably < 5 MPa.
Yet another object is an aircraft structure member, preferably an aircraft upper wing skin element.
Description of the figures Figure 1: Compromise between the toughness Kapp L-T and the compressive yield strength RCp0.2 L of the alloys of Example 1.
Figure 2: Compromise between the toughness Kg L-T and the compressive yield strength RCp0.2 L of the alloys of Example 2.
Figure 3: Compromise between the compressive yield strength RCp0.2 L and the tensile yield strength Rpo.2 L for the alloys of Example 2.
Figure 4: Compromise between the toughness Kapp L-T and the compressive yield strength RCp0.2 L of the alloys of Example 3.
Date Reçue/Date Received 2020-10-09
d) said homogenized crude form is hot-worked, preferably by rolling;
Date Reçue/Date Received 2020-10-09 e) the hot-worked product is solution heat-treated between 490 and 530 C for 15 min to 8 h and said solution heat-treated product is quenched;
f) said product is cold-worked with a working of 2 to 16%;
g) an ageing is carried out wherein said cold-worked product reaches a temperature comprised between 130 and 170 C and preferably between 140 and 160 C for 5 to 100 hours and preferably 10 to 70 hours.
Another object of the invention is an alloy product according to the invention or that can be obtained according to the method of the invention, with a thickness comprised between 8 and 50 mm having, at mid-thickness:
i) a compressive yield strength Rcp0.2(L) > 590 MPa, preferably Rcp0.2(L) >
595 MPa;
ii) a toughness Kapp (L-T) > 60 MPa-Vm, preferably Kapp (L-T) > 75 MPa-Vm, with Kapp (L-T) the value of the apparent stress intensity factor at rupture defined according to standard ASTM E561 (2015) measured on CCT test specimens of width W=406 mm and thickness B = 6.35 mm;
iii) a difference between the tensile yield strength Rpo.2(L) and the compressive yield strength Rcp0.2(L), Rpo.2(L) - Rcpo.2(L), less or equal to 10 MPa, preferably < 5 MPa.
Yet another object is an aircraft structure member, preferably an aircraft upper wing skin element.
Description of the figures Figure 1: Compromise between the toughness Kapp L-T and the compressive yield strength RCp0.2 L of the alloys of Example 1.
Figure 2: Compromise between the toughness Kg L-T and the compressive yield strength RCp0.2 L of the alloys of Example 2.
Figure 3: Compromise between the compressive yield strength RCp0.2 L and the tensile yield strength Rpo.2 L for the alloys of Example 2.
Figure 4: Compromise between the toughness Kapp L-T and the compressive yield strength RCp0.2 L of the alloys of Example 3.
Date Reçue/Date Received 2020-10-09
6 Description of the invention Unless otherwise indicated, ail indications relating to the chemical composition of the alloys are expressed as a percentage by weight based on the total weight of the alloy. The expression 1.4 Cu means that the copper content expressed in % by weight is multiplied by 1.4. The designation of the alloys is made in accordance with the regulations of The Aluminum Association, known to the person skilled in the art. When the concentration is expressed in ppm (parts per million), this indication also refers to a mass concentration.
Unless otherwise indicated, the definitions of metallurgical states given in European standard EN 515 (1993) apply.
The tensile static mechanical features, in other words the ultimate tensile strength Rin, the conventional yield strength at 0.2% elongation Rpo.2, and the elongation at rupture A%, are determined by a tensile test according to standard NF EN ISO 6892-1 (2016), the sampling and direction of the test being defined by standard EN 485 (2016). Rpo.2 (L) means Rpo.2 measured in the longitudinal direction.
The compressive yield strength RCp0.2 was measured at 0.2% compression according to standard ASTM E9-09 (2018). RCp0.2 (L) means RCp0.2 measured in the longitudinal direction.
The stress intensity factor (Kic) is determined according to standard ASTM E
399 (2012).
The stress intensity factor (KQ) is determined according to standard ASTM E
399 (2012).
The standard ASTM E 399 (2012) gives the criteria that allow determining whether KQ is a valid value of Kic. For a given test specimen geometry, the values of KQ
obtained for different materials are comparable with each other provided that the yield strengths of the materials are of the same order of magnitude.
Unless otherwise indicated, the definitions of standard EN 12258 (2012) apply.
The values of the apparent stress intensity factor at rupture (Kapp) and the stress intensity factor at rupture (Ke) are as defined in standard ASTM E561.
A curve giving the effective stress intensity factor as a function of the effective crack extension, known as the curve R, is determined according to standard ASTM E
561 (ASTM
E 561-10-2).
The critical stress intensity factor Kc, in other words the intensity factor which makes the crack unstable, is calculated from the curve R. The stress intensity factor Kco is also Date Reçue/Date Received 2020-10-09
Unless otherwise indicated, the definitions of metallurgical states given in European standard EN 515 (1993) apply.
The tensile static mechanical features, in other words the ultimate tensile strength Rin, the conventional yield strength at 0.2% elongation Rpo.2, and the elongation at rupture A%, are determined by a tensile test according to standard NF EN ISO 6892-1 (2016), the sampling and direction of the test being defined by standard EN 485 (2016). Rpo.2 (L) means Rpo.2 measured in the longitudinal direction.
The compressive yield strength RCp0.2 was measured at 0.2% compression according to standard ASTM E9-09 (2018). RCp0.2 (L) means RCp0.2 measured in the longitudinal direction.
The stress intensity factor (Kic) is determined according to standard ASTM E
399 (2012).
The stress intensity factor (KQ) is determined according to standard ASTM E
399 (2012).
The standard ASTM E 399 (2012) gives the criteria that allow determining whether KQ is a valid value of Kic. For a given test specimen geometry, the values of KQ
obtained for different materials are comparable with each other provided that the yield strengths of the materials are of the same order of magnitude.
Unless otherwise indicated, the definitions of standard EN 12258 (2012) apply.
The values of the apparent stress intensity factor at rupture (Kapp) and the stress intensity factor at rupture (Ke) are as defined in standard ASTM E561.
A curve giving the effective stress intensity factor as a function of the effective crack extension, known as the curve R, is determined according to standard ASTM E
561 (ASTM
E 561-10-2).
The critical stress intensity factor Kc, in other words the intensity factor which makes the crack unstable, is calculated from the curve R. The stress intensity factor Kco is also Date Reçue/Date Received 2020-10-09
7 calculated by assigning the length of the initial crack at the beginning of the monotonic load, to the critical load. These two values are calculated fora test specimen of the required shape.
Kapp represents the factor Kco corresponding to the test specimen which was used to perform the test of curve R. Keff represents the factor Kc corresponding to the test specimen which .. was used to perform the test of curve R.
A mechanical part for which the static and/or dynamic mechanical properties are particularly important for the performance of the structure, and for which a structural calculation is usually required or performed is here called "structure element" or "structural element" of a mechanical construction. These are typically elements the failure of which is likely to endanger the safety of said construction, its users, customers or others. For an airplane, these structure elements comprise in particular the elements that compose the fuselage (such as the fuselage skin), the stiffeners or stringers of the fuselage, the watertight bulkheads, the circumferential frames of the fuselage, the wings (such as the upper or lower wing skin), the stiffeners (or stringers), the ribs and spars and the empennage in particular composed of .. horizontal and vertical stabilizers, as well as floor beams, seat tracks and doors.
According to the present invention, a selected class of aluminum alloys containing in particular specific and critical amounts of lithium, copper, magnesium, silver, manganese and zinc allows to prepare structure elements, in particular upper wing skin sheets, having a high compressive yield strength Rcp0.2(L), a small difference between compressive yield strength Rcp0.2(L) and tensile yield strength Rp0.2(L) and a particularly improved apparent stress intensity factor at rupture Kapp. The selected alloy composition of the invention further allows to obtain all or part of the aforementioned advantages for a wide range of ageing times (in particular a range of at least 5 hours at a given ageing temperature).
Such a composition thus allows to guarantee the robustness of the manufacturing method and therefore to guarantee the final properties of the product during industrial manufacture.
The product based on an aluminum alloy according to the invention comprises, in percentage by weight, 4.0 to 4.6% by weight of Cu; 0.7 to 1.2% by weight of Li; 0.5 to 0.65% by weight of Mg; 0.10 to 0.20% by weight of Zr; 0.15 to 0.30% by weight of Ag; 0.25 to 0.45% by weight of Zn; 0.05 to 0.35% by weight of Mn; at most 0.20% by weight of Fe +
Si; at least Date Reçue/Date Received 2020-10-09
Kapp represents the factor Kco corresponding to the test specimen which was used to perform the test of curve R. Keff represents the factor Kc corresponding to the test specimen which .. was used to perform the test of curve R.
A mechanical part for which the static and/or dynamic mechanical properties are particularly important for the performance of the structure, and for which a structural calculation is usually required or performed is here called "structure element" or "structural element" of a mechanical construction. These are typically elements the failure of which is likely to endanger the safety of said construction, its users, customers or others. For an airplane, these structure elements comprise in particular the elements that compose the fuselage (such as the fuselage skin), the stiffeners or stringers of the fuselage, the watertight bulkheads, the circumferential frames of the fuselage, the wings (such as the upper or lower wing skin), the stiffeners (or stringers), the ribs and spars and the empennage in particular composed of .. horizontal and vertical stabilizers, as well as floor beams, seat tracks and doors.
According to the present invention, a selected class of aluminum alloys containing in particular specific and critical amounts of lithium, copper, magnesium, silver, manganese and zinc allows to prepare structure elements, in particular upper wing skin sheets, having a high compressive yield strength Rcp0.2(L), a small difference between compressive yield strength Rcp0.2(L) and tensile yield strength Rp0.2(L) and a particularly improved apparent stress intensity factor at rupture Kapp. The selected alloy composition of the invention further allows to obtain all or part of the aforementioned advantages for a wide range of ageing times (in particular a range of at least 5 hours at a given ageing temperature).
Such a composition thus allows to guarantee the robustness of the manufacturing method and therefore to guarantee the final properties of the product during industrial manufacture.
The product based on an aluminum alloy according to the invention comprises, in percentage by weight, 4.0 to 4.6% by weight of Cu; 0.7 to 1.2% by weight of Li; 0.5 to 0.65% by weight of Mg; 0.10 to 0.20% by weight of Zr; 0.15 to 0.30% by weight of Ag; 0.25 to 0.45% by weight of Zn; 0.05 to 0.35% by weight of Mn; at most 0.20% by weight of Fe +
Si; at least Date Reçue/Date Received 2020-10-09
8 one element selected from Cr, Sc, Hf, V and Ti; other elements at most 0.05%
by weight each and 0.15% by weight in total and the remainder being aluminum.
The copper content of the products according to the invention is comprised between 4.0 and 4.6% by weight, preferably between 4.2 and 4.5% by weight and more preferably between 4.2 and 4.4% by weight. In an advantageous embodiment, the minimum copper content is 4.25% by weight.
The lithium content of the products according to the invention is comprised between 0.7 to 1.2% by weight. Advantageously, the lithium content is comprised between 0.8 and 1.0% by weight; preferably between 0.85 and 0.95% by weight.
The increase in the copper content and to a lesser extent the lithium content contributes to improving the static mechanical strength, however, copper having a detrimental effect in particular on the density, it is preferable to limit the copper content to the preferred maximum value of 4.4% by weight. The increase in the lithium content has a favorable effect on the density, however the present inventors have observed that for the alloys according to the invention, the preferred lithium content comprised between 0.85% and 0.95% by weight allows an improvement in the compromise between mechanical strength (tensile and compressive yield strength) and toughness. A high lithium content, in particular above the preferred maximum value of 0.95% by weight, can lead to a degradation of the toughness.
The magnesium content of the products according to the invention is comprised between 0.5% and 0.65% by weight. Preferably, the magnesium content is at least 0.50%
or even at least 0.55% by weight, which simultaneously improves static mechanical strength and toughness. In particular, for the selected compositions of the present invention, a magnesium content greater than 0.65% by weight can induce a degradation of the toughness.
The zinc and silver contents are respectively comprised between 0.25 and 0.45%
by weight and 0.15 and 0.30% by weight. Such zinc and silver contents are necessary to guarantee a compressive yield strength having a value close to that of the tensile yield strength. In an advantageous embodiment, the products according to the invention have a difference between the tensile yield strength Rpo.2(L) and the compressive yield strength Rcp0.2(L) less than or equal to 10 MPa, preferably less than or equal to 5 MPa.
Date Reçue/Date Received 2020-10-09
by weight each and 0.15% by weight in total and the remainder being aluminum.
The copper content of the products according to the invention is comprised between 4.0 and 4.6% by weight, preferably between 4.2 and 4.5% by weight and more preferably between 4.2 and 4.4% by weight. In an advantageous embodiment, the minimum copper content is 4.25% by weight.
The lithium content of the products according to the invention is comprised between 0.7 to 1.2% by weight. Advantageously, the lithium content is comprised between 0.8 and 1.0% by weight; preferably between 0.85 and 0.95% by weight.
The increase in the copper content and to a lesser extent the lithium content contributes to improving the static mechanical strength, however, copper having a detrimental effect in particular on the density, it is preferable to limit the copper content to the preferred maximum value of 4.4% by weight. The increase in the lithium content has a favorable effect on the density, however the present inventors have observed that for the alloys according to the invention, the preferred lithium content comprised between 0.85% and 0.95% by weight allows an improvement in the compromise between mechanical strength (tensile and compressive yield strength) and toughness. A high lithium content, in particular above the preferred maximum value of 0.95% by weight, can lead to a degradation of the toughness.
The magnesium content of the products according to the invention is comprised between 0.5% and 0.65% by weight. Preferably, the magnesium content is at least 0.50%
or even at least 0.55% by weight, which simultaneously improves static mechanical strength and toughness. In particular, for the selected compositions of the present invention, a magnesium content greater than 0.65% by weight can induce a degradation of the toughness.
The zinc and silver contents are respectively comprised between 0.25 and 0.45%
by weight and 0.15 and 0.30% by weight. Such zinc and silver contents are necessary to guarantee a compressive yield strength having a value close to that of the tensile yield strength. In an advantageous embodiment, the products according to the invention have a difference between the tensile yield strength Rpo.2(L) and the compressive yield strength Rcp0.2(L) less than or equal to 10 MPa, preferably less than or equal to 5 MPa.
Date Reçue/Date Received 2020-10-09
9 The presence of silver and zinc allows to obtain a good compromise between the various desired properties. In particular, the presence of silver allows to obtain a product in a reliable and robust manner, that is to say that the desired compromise in properties is achieved for a wide range of ageing times, in particular a time range greater than 5 hours, which is compatible with the variability inherent in an industrial manufacturing method. A minimum content of 0.20% by weight of silver is advantageous. A maximum content of 0.27% by weight of silver is advantageous.
A minimum content of 0.30% by weight of zinc is advantageous. A maximum content of 0.40% by weight of zinc is advantageous. Preferably, the Zn content is comprised between 0.30 and 0.40% by weight.
Advantageously, the sum of the Zn, Mg and Ag contents comprised between 0.95 and 1.35%
by weight, preferably between 1.00 and 1.30% by weight, more preferably still between 1.15 and 1.25% by weight. The present inventors have observed that the desired optimum compromise in properties, in particular for elements of the upper wing skin, was only achieved for specific and critical values of the sum of Zn, Mg and Ag.
The manganese content is comprised between 0.05 and 0.35% by weight.
Advantageously, the Mn content comprised between 0.10 and 0.35% by weight. In one embodiment, the manganese content is comprised between 0.2 and 0.35% by weight and preferably between 0.25 and 0.35% by weight. In another embodiment, the manganese content is comprised between 0.1 and 0.2% by weight and preferably between 0.10 and 0.20% by weight. In particular, the addition of Mn allows to obtain high toughness. However, if the Mn content is greater than 0.35% by weight, the fatigue life can be significantly reduced.
The Zr content of the alloy is comprised between 0.10 and 0.20% by weight. In an advantageous embodiment, the Zr content is comprised between 0.10 and 0.15% by weight, preferably between 0.11 and 0.14% by weight.
The sum of the iron content and the silicon content is at most 0.20% by weight. Preferably, the iron and silicon contents are each at most 0.08% by weight. In an advantageous embodiment of the invention the iron and silicon contents are at most 0.06%
and 0.04% by weight, respectively. A controlled and limited iron and silicon content helps improve the compromise between mechanical strength and damage tolerance.
Date Reçue/Date Received 2020-10-09 lo The alloy also contains at least one element which can contribute to the control of the grain size selected from Cr, Sc, Hf, V and Ti, the amount of said element, if selected, being from 0.05 to 0.3% by weight for Cr and for Sc, 0.05 to 0.5% by weight for Hf and for V and from 0.01 to 0.15% by weight for Ti. In an advantageous embodiment, it is selected to add between 0.01 and 0.15% by weight of titanium. In a preferred embodiment, the Ti content is comprised between 0.01 and 0.08% by weight, preferably between 0.02 and 0.06% by weight.
Advantageously in the embodiments wherein it is selected to add titanium, the content of Cr, Sc, V and Hf is limited to a maximum content of 0.05% by weight, these elements possibly having an unfavorable effect, in particular on the density and being added only to further promote the production of an essentially non-recrystallized structure if necessary. In a particularly advantageous manner, the Ti is present in particular in the form of particles of TiC. Against ail expectations, the present inventors have observed that, in the particular case of the present alloy, the presence of particles of TiC in the grain refining rod during casting (AlTiC refining), allows to obtain a product having an optimized compromise in properties.
Advantageously the refiner has the formula AlTiC y which is also written ATxCy where x and y are the contents of Ti and C in % by weight for 1% by weight of Al, and x/y> 4. In particular, the AlTiC refinement in the alloy of the present invention allows an improvement of the compromise between the toughness Kapp L-T and the compressive yield strength Rep0.2 L.
The content of the alloy elements can be selected to minimize the density.
Preferably, the additive elements contributing to increase the density such as Cu, Zn, Mn and Ag are minimized and the elements contributing to decrease the density such as Li and Mg are maximized so as to achieve a density less than or equal to 2.73 g/cm3 and preferably less than or equal to 2.72 g/cm3.
The content of the other elements is at most 0.05% by weight each and 0.15% by weight in total. The other elements are typically unavoidable impurities.
The method for manufacturing products according to the invention comprises the steps of preparation, casting, homogenization, hot working, solution heat-treating and quenching, tensioning between 2 and 16% and ageing.
In a first step, a liquid metal bath is prepared so as to obtain an aluminum alloy of a composition according to the invention.
Date Reçue/Date Received 2020-10-09 The liquid metal bath is then cast in the form of crude form, preferably in the shape of a ingot for rolling or an extrusion billet.
The crude fonn is then homogenized so as to reach a temperature comprised between 450 C
and 5500 and preferably between 480 C and 530 C for a period comprised between 5 and 60 hours. The homogenization treatment can be carried out in one or more stages.
After homogenization, the crude form is generally cooled to room temperature before being preheated in order to be hot-worked. The hot working can in particular be an extrusion or a hot rolling. Preferably, this is a hot rolling step. The hot rolling is carried out to a thickness preferably comprised between 8 and 50 mm and in a preferred manner between 15 and 40 mm.
The product thus obtained is then solution heat-treated to reach a temperature comprised between 490 and 530 C for 15 min to 8 h, then quenched typically with water at room temperature.
The product then undergoes cold working with a working of 2 to 16%. It can be a controlled tensioning with a permanent set of 2 to 5%, preferably from 2.0% to 4.0%. In an alternative advantageous embodiment, the cold working is carried out in two steps: the product is first of all cold rolled with a thickness reduction rate comprised between 8 to 12%
then subsequently tensioned in a controlled manner with a permanent set comprised between 0.5 and 4%.
The product is then subjected to an ageing step carried out by heating at a temperature comprised between 130 and 170 C and preferably between 140 and 160 C for 5 to 100 hours and preferably 10 to 70 hours.
The present inventors have observed that, surprisingly, the specific and critical contents of the alloy of the present invention allow to achieve excellent properties, in particular a compromise between the compressive yield strength Rcp0.2(L) and toughness in plane stresses Kapp particularly improved. Advantageously, these properties can be obtained, for the alloys of the invention, regardless of the ageing time between 15h and 25h at 155 C, which guarantees the robustness of the manufacturing method.
Date Reçue/Date Received 2020-10-09 Advantageously, the granular structure of the products obtained is predominantly non-recrystallized. The rate of non-recrystallized granular mid-thickness structure is preferably at least 70% and preferably at least 80%.
The products obtained by the method according to the invention, in particular the rolled products having a thickness comprised between 8 and 50 mm, at mid-thickness, have the following features:
i) a compressive yield strength Rcpo.2(L) > 590 MPa, preferably Rcp0.2(L) >
595 MPa, with Rcp0.2(L) the compressive yield strength measured at 0.2% compression according to the standard ASTM E9 (2018) in the longitudinal direction;
ii) a toughness Kapp (L-T) > 60 MPa-\im, preferably Kapp (L-T) > 75 MPa-Vm, with Kapp (L-T) the value of the apparent stress intensity factor at rupture defined according to standard ASTM E561 (2015) measured on CCT test specimens of width W = 406 mm and thickness B = 6.35 mm;
iii) a difference between the tensile yield strength Rpo.2(L) and the compressive yield strength RCp0.2(L), Rp0.2(1-.) - RCp0.2(L), less than or equal to 10 MPa, preferably < 5 MPa.
Advantageously, the features i) and ii) are obtained for a wide range of ageing time, in particular a range of at least 5 hours at a given ageing temperature. Such a composition thus allows to guarantee the robustness of the manufacturing method and therefore to guarantee the final properties of the product during industrial manufacture.
In an advantageous embodiment, the toughness is such that Kapp (L-T) > -0.48 Rcp0.2(L) +
355.2, with Kapp (L-T) expressed in MPa-Vm, the value of the apparent stress intensity factor at rupture defined according to standard ASTM E561 (2015) measured on CCT test specimens of width W = 406 mm and thickness B = 6.35 mm, and RCp0.2 (L) expressed in MPa, the compressive yield strength measured at 0.2% compression according to standard ASTM E9 (2018).
The alloy products according to the invention allow in particular the manufacture of structure elements, in particular aircraft structure elements. In an advantageous embodiment, the preferred aircraft structure element is an aircraft upper wing skin element.
Date Reçue/Date Received 2020-10-09 These and other aspects of the invention are explained in more detail using the following illustrative and non-limiting examples.
Examples Example 1.
In this example, plates with a section of 406 x 1520 mm made of an alloy, the composition of which is given in Table 1, were cast.
Table 1. Composition in % by wei2,ht of alloys N 1 to 8 Alloy Si Fe Cu Mn Mg Zn Ti Zr Li Ag 1 0.02 0.03 4.6 0.32 0.62 0.62 0.03 0.13 0.91 0.01 2 0.02 0.03 4.3 0.31 0.60 0.35 0.03 0.12 0.91 0.24 3 0.03 0.05 4.5 0.34 0.71 0.04 0.04 0.11 1.03 0.21 4 0.03 0.04 4.3 - 0.33 0.03 0.02 0.15 1.13 0.21 5 0.03 0.04 4.2 0.33 0.54 - 0.03 0.13 0.88 0.19 6 0.02 0.04 4.4 0.02 0.21 0.04 0.02 0.14 1.05 0.21 7 0.03 0.04 3.9 - 0.36 - 0.03 0.11 1.31 0.36 8 0.04 0.06 4.1 0.42 0.42 0.02 0.02 0.15 1.18 0.29 For each composition, the plate was homogenized with a lst stage of 15h at 500 C, followed by a second stage of 20h at 510 C. The plate was hot rolled at a temperature above 440 C
to obtain sheets of a thickness of 25 mm for alloys 2 to 8 and 28 mm for alloy 1. The sheets were solution heat-treated at about 510 C for 3 h, water quenched at 20 C.
The sheets were then tensioned with a permanent elongation comprised between 2% and 6%.
The sheets underwent a single-stage ageing as indicated in Table 2. Samples were taken at mid-thickness to measure the static mechanical features in tension and in compression in the longitudinal direction. The toughness in plane stress was also measured at mid-thickness during tests of curve R with CCT test specimens 406 mm wide and 6.35 mm thick in the L-T direction. The results are shown in Table 2 and Figure 1.
Date Reçue/Date Received 2020-10-09 The structure of the obtained sheets was mostly non-recrystallized. The rate of non-recrystallized granular mid-thickness structure was 90%.
Table 2. Controlled tensile and ageing conditions and mechanical properties obtained for the various mid-thickness sheets.
Permanent elongation RP0.2 (L) RCp0.2 (L) Kapp (L-T) Alloy Ageing during Tension Compression (MPa Vm) controlled (Mpa) (Mpa) tensioning 15h 155 C 3.0 593 585 71 20h 155 C 3.0 604 610 59 15h 155 C 3.0 591 593 76 2 20h 155 C 3.0 601 599 69 25h 155 C 3.0 613 63 3 15h 155 C 3.3 612 607 60 15h 155 C 3.1 619 614 59 20h 155 C 3.1 636 637 55 20h 155 C 3.2 574 570 105 25h 155 C 3.2 585 580 79 6 20h 155 C 3.1 628 628 51 7 24h 150 C 4.5 606 590 64 8 24h 150 C 4.0 594 587 72 Example 2 In this example, in addition to the alloy plate 2 of example 1, a plate with a section of 406 x 1520 mm, the composition of which is given in Table 3, was cast.
Table 3, Composition in % by weight of alloys 2 and 10, Alloy Si Fe Cu Mn Mg Zn Ti Zr Li Ag 0.02 0.03 4.3 0.31 0.60 0.35 0.03 0.12 0.91 0.24
A minimum content of 0.30% by weight of zinc is advantageous. A maximum content of 0.40% by weight of zinc is advantageous. Preferably, the Zn content is comprised between 0.30 and 0.40% by weight.
Advantageously, the sum of the Zn, Mg and Ag contents comprised between 0.95 and 1.35%
by weight, preferably between 1.00 and 1.30% by weight, more preferably still between 1.15 and 1.25% by weight. The present inventors have observed that the desired optimum compromise in properties, in particular for elements of the upper wing skin, was only achieved for specific and critical values of the sum of Zn, Mg and Ag.
The manganese content is comprised between 0.05 and 0.35% by weight.
Advantageously, the Mn content comprised between 0.10 and 0.35% by weight. In one embodiment, the manganese content is comprised between 0.2 and 0.35% by weight and preferably between 0.25 and 0.35% by weight. In another embodiment, the manganese content is comprised between 0.1 and 0.2% by weight and preferably between 0.10 and 0.20% by weight. In particular, the addition of Mn allows to obtain high toughness. However, if the Mn content is greater than 0.35% by weight, the fatigue life can be significantly reduced.
The Zr content of the alloy is comprised between 0.10 and 0.20% by weight. In an advantageous embodiment, the Zr content is comprised between 0.10 and 0.15% by weight, preferably between 0.11 and 0.14% by weight.
The sum of the iron content and the silicon content is at most 0.20% by weight. Preferably, the iron and silicon contents are each at most 0.08% by weight. In an advantageous embodiment of the invention the iron and silicon contents are at most 0.06%
and 0.04% by weight, respectively. A controlled and limited iron and silicon content helps improve the compromise between mechanical strength and damage tolerance.
Date Reçue/Date Received 2020-10-09 lo The alloy also contains at least one element which can contribute to the control of the grain size selected from Cr, Sc, Hf, V and Ti, the amount of said element, if selected, being from 0.05 to 0.3% by weight for Cr and for Sc, 0.05 to 0.5% by weight for Hf and for V and from 0.01 to 0.15% by weight for Ti. In an advantageous embodiment, it is selected to add between 0.01 and 0.15% by weight of titanium. In a preferred embodiment, the Ti content is comprised between 0.01 and 0.08% by weight, preferably between 0.02 and 0.06% by weight.
Advantageously in the embodiments wherein it is selected to add titanium, the content of Cr, Sc, V and Hf is limited to a maximum content of 0.05% by weight, these elements possibly having an unfavorable effect, in particular on the density and being added only to further promote the production of an essentially non-recrystallized structure if necessary. In a particularly advantageous manner, the Ti is present in particular in the form of particles of TiC. Against ail expectations, the present inventors have observed that, in the particular case of the present alloy, the presence of particles of TiC in the grain refining rod during casting (AlTiC refining), allows to obtain a product having an optimized compromise in properties.
Advantageously the refiner has the formula AlTiC y which is also written ATxCy where x and y are the contents of Ti and C in % by weight for 1% by weight of Al, and x/y> 4. In particular, the AlTiC refinement in the alloy of the present invention allows an improvement of the compromise between the toughness Kapp L-T and the compressive yield strength Rep0.2 L.
The content of the alloy elements can be selected to minimize the density.
Preferably, the additive elements contributing to increase the density such as Cu, Zn, Mn and Ag are minimized and the elements contributing to decrease the density such as Li and Mg are maximized so as to achieve a density less than or equal to 2.73 g/cm3 and preferably less than or equal to 2.72 g/cm3.
The content of the other elements is at most 0.05% by weight each and 0.15% by weight in total. The other elements are typically unavoidable impurities.
The method for manufacturing products according to the invention comprises the steps of preparation, casting, homogenization, hot working, solution heat-treating and quenching, tensioning between 2 and 16% and ageing.
In a first step, a liquid metal bath is prepared so as to obtain an aluminum alloy of a composition according to the invention.
Date Reçue/Date Received 2020-10-09 The liquid metal bath is then cast in the form of crude form, preferably in the shape of a ingot for rolling or an extrusion billet.
The crude fonn is then homogenized so as to reach a temperature comprised between 450 C
and 5500 and preferably between 480 C and 530 C for a period comprised between 5 and 60 hours. The homogenization treatment can be carried out in one or more stages.
After homogenization, the crude form is generally cooled to room temperature before being preheated in order to be hot-worked. The hot working can in particular be an extrusion or a hot rolling. Preferably, this is a hot rolling step. The hot rolling is carried out to a thickness preferably comprised between 8 and 50 mm and in a preferred manner between 15 and 40 mm.
The product thus obtained is then solution heat-treated to reach a temperature comprised between 490 and 530 C for 15 min to 8 h, then quenched typically with water at room temperature.
The product then undergoes cold working with a working of 2 to 16%. It can be a controlled tensioning with a permanent set of 2 to 5%, preferably from 2.0% to 4.0%. In an alternative advantageous embodiment, the cold working is carried out in two steps: the product is first of all cold rolled with a thickness reduction rate comprised between 8 to 12%
then subsequently tensioned in a controlled manner with a permanent set comprised between 0.5 and 4%.
The product is then subjected to an ageing step carried out by heating at a temperature comprised between 130 and 170 C and preferably between 140 and 160 C for 5 to 100 hours and preferably 10 to 70 hours.
The present inventors have observed that, surprisingly, the specific and critical contents of the alloy of the present invention allow to achieve excellent properties, in particular a compromise between the compressive yield strength Rcp0.2(L) and toughness in plane stresses Kapp particularly improved. Advantageously, these properties can be obtained, for the alloys of the invention, regardless of the ageing time between 15h and 25h at 155 C, which guarantees the robustness of the manufacturing method.
Date Reçue/Date Received 2020-10-09 Advantageously, the granular structure of the products obtained is predominantly non-recrystallized. The rate of non-recrystallized granular mid-thickness structure is preferably at least 70% and preferably at least 80%.
The products obtained by the method according to the invention, in particular the rolled products having a thickness comprised between 8 and 50 mm, at mid-thickness, have the following features:
i) a compressive yield strength Rcpo.2(L) > 590 MPa, preferably Rcp0.2(L) >
595 MPa, with Rcp0.2(L) the compressive yield strength measured at 0.2% compression according to the standard ASTM E9 (2018) in the longitudinal direction;
ii) a toughness Kapp (L-T) > 60 MPa-\im, preferably Kapp (L-T) > 75 MPa-Vm, with Kapp (L-T) the value of the apparent stress intensity factor at rupture defined according to standard ASTM E561 (2015) measured on CCT test specimens of width W = 406 mm and thickness B = 6.35 mm;
iii) a difference between the tensile yield strength Rpo.2(L) and the compressive yield strength RCp0.2(L), Rp0.2(1-.) - RCp0.2(L), less than or equal to 10 MPa, preferably < 5 MPa.
Advantageously, the features i) and ii) are obtained for a wide range of ageing time, in particular a range of at least 5 hours at a given ageing temperature. Such a composition thus allows to guarantee the robustness of the manufacturing method and therefore to guarantee the final properties of the product during industrial manufacture.
In an advantageous embodiment, the toughness is such that Kapp (L-T) > -0.48 Rcp0.2(L) +
355.2, with Kapp (L-T) expressed in MPa-Vm, the value of the apparent stress intensity factor at rupture defined according to standard ASTM E561 (2015) measured on CCT test specimens of width W = 406 mm and thickness B = 6.35 mm, and RCp0.2 (L) expressed in MPa, the compressive yield strength measured at 0.2% compression according to standard ASTM E9 (2018).
The alloy products according to the invention allow in particular the manufacture of structure elements, in particular aircraft structure elements. In an advantageous embodiment, the preferred aircraft structure element is an aircraft upper wing skin element.
Date Reçue/Date Received 2020-10-09 These and other aspects of the invention are explained in more detail using the following illustrative and non-limiting examples.
Examples Example 1.
In this example, plates with a section of 406 x 1520 mm made of an alloy, the composition of which is given in Table 1, were cast.
Table 1. Composition in % by wei2,ht of alloys N 1 to 8 Alloy Si Fe Cu Mn Mg Zn Ti Zr Li Ag 1 0.02 0.03 4.6 0.32 0.62 0.62 0.03 0.13 0.91 0.01 2 0.02 0.03 4.3 0.31 0.60 0.35 0.03 0.12 0.91 0.24 3 0.03 0.05 4.5 0.34 0.71 0.04 0.04 0.11 1.03 0.21 4 0.03 0.04 4.3 - 0.33 0.03 0.02 0.15 1.13 0.21 5 0.03 0.04 4.2 0.33 0.54 - 0.03 0.13 0.88 0.19 6 0.02 0.04 4.4 0.02 0.21 0.04 0.02 0.14 1.05 0.21 7 0.03 0.04 3.9 - 0.36 - 0.03 0.11 1.31 0.36 8 0.04 0.06 4.1 0.42 0.42 0.02 0.02 0.15 1.18 0.29 For each composition, the plate was homogenized with a lst stage of 15h at 500 C, followed by a second stage of 20h at 510 C. The plate was hot rolled at a temperature above 440 C
to obtain sheets of a thickness of 25 mm for alloys 2 to 8 and 28 mm for alloy 1. The sheets were solution heat-treated at about 510 C for 3 h, water quenched at 20 C.
The sheets were then tensioned with a permanent elongation comprised between 2% and 6%.
The sheets underwent a single-stage ageing as indicated in Table 2. Samples were taken at mid-thickness to measure the static mechanical features in tension and in compression in the longitudinal direction. The toughness in plane stress was also measured at mid-thickness during tests of curve R with CCT test specimens 406 mm wide and 6.35 mm thick in the L-T direction. The results are shown in Table 2 and Figure 1.
Date Reçue/Date Received 2020-10-09 The structure of the obtained sheets was mostly non-recrystallized. The rate of non-recrystallized granular mid-thickness structure was 90%.
Table 2. Controlled tensile and ageing conditions and mechanical properties obtained for the various mid-thickness sheets.
Permanent elongation RP0.2 (L) RCp0.2 (L) Kapp (L-T) Alloy Ageing during Tension Compression (MPa Vm) controlled (Mpa) (Mpa) tensioning 15h 155 C 3.0 593 585 71 20h 155 C 3.0 604 610 59 15h 155 C 3.0 591 593 76 2 20h 155 C 3.0 601 599 69 25h 155 C 3.0 613 63 3 15h 155 C 3.3 612 607 60 15h 155 C 3.1 619 614 59 20h 155 C 3.1 636 637 55 20h 155 C 3.2 574 570 105 25h 155 C 3.2 585 580 79 6 20h 155 C 3.1 628 628 51 7 24h 150 C 4.5 606 590 64 8 24h 150 C 4.0 594 587 72 Example 2 In this example, in addition to the alloy plate 2 of example 1, a plate with a section of 406 x 1520 mm, the composition of which is given in Table 3, was cast.
Table 3, Composition in % by weight of alloys 2 and 10, Alloy Si Fe Cu Mn Mg Zn Ti Zr Li Ag 0.02 0.03 4.3 0.31 0.60 0.35 0.03 0.12 0.91 0.24
10 0.04 0.02 4.3 0.31 0.64 0.33 0.03 0.14 0.90 0.35 Date Reçue/Date Received 2020-10-09 The plates were homogenized at about 510 C then scalped. After homogenization, the plates were hot rolled to obtain sheets having a thickness of 25 mm. The sheets were solution heat-treated for 3 hours at about 510 C, quenched in cold water and tensioned with a permanent elongation of 3%.
The structure of the sheets obtained was predominantly non-recrystallized. The rate of non-recrystallized mid-thickness granular structure was 90%.
The sheets were tempered between 15 h and 50 h at 155 C. Samples were taken at mid-10 thickness to measure the static mechanical features in tension, in compression in the longitudinal direction as well as the toughness KQ in the L-T direction. The test specimens used for the toughness measurement had a width W = 40 mm and a thickness B =
20 mm.
The results obtained are presented in Table 4 and Figures 2 and 3.
Table 4: Ageing conditions and mechanical properties obtained for the sheets 2 and 10.
Difference Tension properties Compression properties Toughness between Rpo.2 (MPa) in Alloy Ageing RD0.2 Rm tension and A Rcp0.2(L) (MPa) KQ
time at (L) (L) RD0.2 (MPa) in (%) (MPa-Vm) L-T
155 C (MPa) (MPa) compression N 2 10h 560 598 10 565 -5 15h 591 617 8.3 593 30.6 -2 20h 601 625 8.5 599 29.9 2 25h 613 27.6 30h 609 632 7.9 615 -6 N 10 10h 587 620 10 559 28 15h 604 632 8.5 588 30.7 16 20h 620 644 8.2 607 25.1 13 25h 609 24.8 30h 621 645 7.5 609 12 Date Reçue/Date Received 2020-10-09 Example 3 In this example, in addition to the plate of alloy 2 of example 1, a plate with a section 406 x 1700 mm, the composition of which is given in Table 3 was cast using an AlTiC
refining (grain refining rod containing nuclei of the TiC type).
Table 5. Composition in % by weight of alloys 2 and 9.
Alloy Si Fe Cu Mn Mg Zn Ti Zr Li Ag 2 0.02 0.03 4.3 0.31 0.60 0.35 0.03 0.12 0.91 0.24 9 0.02 0.04 4.3 0.14 0.61 0.36 0.05 0.13 0.88 0.25 The plates were homogenized at about 510 C then scalped. After homogenization, the plates were hot rolled to obtain sheets having a thickness of 25mm. The sheets were solution heat-treated for 3h at around 510 C, quenched in cold water and tensioned with a permanent elongation of 3%.
The sheets were tempered between 15 h and 25 h at 155 C. Samples were taken at mid-thickness to measure the static mechanical features in tension, in compression in the longitudinal direction as well as the toughness KQ in the L-T direction. The test specimens used for the toughness measurement had a width W = 40 mm and a thickness B =
20 mm.
The validity criteria of Kic were met for some samples. Measurements of toughness in plane stress were also obtained on CCT samples 406 mm wide and 6.35 mm thick. The results obtained are presented in Table 6 and in Figure 4.
Date Reçue/Date Received 2020-10-09 Table 6: Ageing conditions and mechanical properties obtained for sheets 2 and 9 at mid-thickness Tension properties Compression properties Toughness Alloy Rpo.2 (L) Ageing Rm (L) in A Rcp0.2 (L) KQ Kapp L-T L-T
time at (MPa) tension (%) (MPa) (MPa.m1/2) (MPa.m1/2) 155 C (MPa) N 2 15h 591 617 8.3 593 30.6 76 20h 601 625 8.5 599 29.9 69 25h 613 27.6 63 N 9 15h 597 622 9.1 599 28.7 84 20h 603 26.8 80 25h 602 626 8.5 607 26.9 78 Date Reçue/Date Received 2020-10-09
The structure of the sheets obtained was predominantly non-recrystallized. The rate of non-recrystallized mid-thickness granular structure was 90%.
The sheets were tempered between 15 h and 50 h at 155 C. Samples were taken at mid-10 thickness to measure the static mechanical features in tension, in compression in the longitudinal direction as well as the toughness KQ in the L-T direction. The test specimens used for the toughness measurement had a width W = 40 mm and a thickness B =
20 mm.
The results obtained are presented in Table 4 and Figures 2 and 3.
Table 4: Ageing conditions and mechanical properties obtained for the sheets 2 and 10.
Difference Tension properties Compression properties Toughness between Rpo.2 (MPa) in Alloy Ageing RD0.2 Rm tension and A Rcp0.2(L) (MPa) KQ
time at (L) (L) RD0.2 (MPa) in (%) (MPa-Vm) L-T
155 C (MPa) (MPa) compression N 2 10h 560 598 10 565 -5 15h 591 617 8.3 593 30.6 -2 20h 601 625 8.5 599 29.9 2 25h 613 27.6 30h 609 632 7.9 615 -6 N 10 10h 587 620 10 559 28 15h 604 632 8.5 588 30.7 16 20h 620 644 8.2 607 25.1 13 25h 609 24.8 30h 621 645 7.5 609 12 Date Reçue/Date Received 2020-10-09 Example 3 In this example, in addition to the plate of alloy 2 of example 1, a plate with a section 406 x 1700 mm, the composition of which is given in Table 3 was cast using an AlTiC
refining (grain refining rod containing nuclei of the TiC type).
Table 5. Composition in % by weight of alloys 2 and 9.
Alloy Si Fe Cu Mn Mg Zn Ti Zr Li Ag 2 0.02 0.03 4.3 0.31 0.60 0.35 0.03 0.12 0.91 0.24 9 0.02 0.04 4.3 0.14 0.61 0.36 0.05 0.13 0.88 0.25 The plates were homogenized at about 510 C then scalped. After homogenization, the plates were hot rolled to obtain sheets having a thickness of 25mm. The sheets were solution heat-treated for 3h at around 510 C, quenched in cold water and tensioned with a permanent elongation of 3%.
The sheets were tempered between 15 h and 25 h at 155 C. Samples were taken at mid-thickness to measure the static mechanical features in tension, in compression in the longitudinal direction as well as the toughness KQ in the L-T direction. The test specimens used for the toughness measurement had a width W = 40 mm and a thickness B =
20 mm.
The validity criteria of Kic were met for some samples. Measurements of toughness in plane stress were also obtained on CCT samples 406 mm wide and 6.35 mm thick. The results obtained are presented in Table 6 and in Figure 4.
Date Reçue/Date Received 2020-10-09 Table 6: Ageing conditions and mechanical properties obtained for sheets 2 and 9 at mid-thickness Tension properties Compression properties Toughness Alloy Rpo.2 (L) Ageing Rm (L) in A Rcp0.2 (L) KQ Kapp L-T L-T
time at (MPa) tension (%) (MPa) (MPa.m1/2) (MPa.m1/2) 155 C (MPa) N 2 15h 591 617 8.3 593 30.6 76 20h 601 625 8.5 599 29.9 69 25h 613 27.6 63 N 9 15h 597 622 9.1 599 28.7 84 20h 603 26.8 80 25h 602 626 8.5 607 26.9 78 Date Reçue/Date Received 2020-10-09
Claims (11)
1. A product based on an aluminum alloy comprising, in percentage by weight, 4.0 to 4.6% by weight of Cu, 0.7 to 1.2% by weight of Li, 0.5 to 0.65% by weight of Mg, 0.10 to 0.20% by weight of Zr, 0.15 to 0.30% by weight of Ag, 0.25 to 0.45% by weight of Zn, 0.05 to 0.35% by weight of Mn, at most 0.20% by weight of Fe + Si, at least one element selected from Cr, Sc, Hf, V and Ti, the amount of said element, if selected, being from 0.05 to 0.3% by weight for Cr and for Sc, 0.05 to 0.5%
by weight for Hf and for V and from 0.01 to 0.15% by weight for Ti, other elements at most 0.05% by weight each and 0.15% by weight in total, the remainder being aluminum.
by weight for Hf and for V and from 0.01 to 0.15% by weight for Ti, other elements at most 0.05% by weight each and 0.15% by weight in total, the remainder being aluminum.
2. The product based on an aluminum alloy according to claim 1 wherein the Cu content is comprised between 4.2 and 4.5% by weight, preferably between 4.2 and 4.4% by weight.
3. The product based on an aluminum alloy according to claim 1 or claim 2 wherein the Li content is comprised between 0.8 and 1.0% by weight, preferably between 0.85 and 0.95% by weight.
4. The product based on an aluminum alloy according to any one of claims 1 to 3 wherein the Zn content is comprised between 0.30 and 0.40% by weight.
5. The product based on an aluminum alloy according to any one of claims 1 to 4 wherein the Mn content comprised between 0.10 and 0.35% by weight.
6. The product based on an aluminum alloy according to any one of claims 1 to 5 wherein the sum of the Zn, Mg and Ag contents comprised between 0.95 and 1.35% by weight, Date Reçue/Date Received 2020-10-09 preferably between 1.00 and 1.30% by weight, more preferably still between 1.15 and 1.25% by weight.
7. The product based on an aluminum alloy according to any one of claims 1 to 6 wherein the Zr content is 0.10 to 0.15% by weight, preferably between 0.11 and 0.14%
by weight.
by weight.
8. The product based on an aluminum alloy according to any one of claims 1 to 7 wherein the Ti content is comprised between 0.01 to 0.15% by weight for Ti, preferably between 0.01 and 0.08% by weight, more preferably between 0.02 and 0.06% by weight.
9. The product based on an aluminum alloy according to claim 8 wherein the Ti is present in particular in the fonn of particles of TiC.
10. A method for manufacturing a product based on an aluminum alloy wherein, successively, b) a liquid metal bath based on aluminum is prepared comprising 4.0 to 4.6% by weight of Cu; 0.7 fo 1.2% by weight of Li; 0.5 fo 0.65% by weight of Mg; 0.10 fo 0.20% by weight of Zr; 0.15 to 0.30% by weight of Ag; 0.25 to 0.45% by weight of Zn; 0.05 to 0.35% by weight of Mn; at most 0.20% by weight of Fe + Si; at least one element selected from Cr, Sc, Hf, V and Ti, the amount of said element, if selected, being from 0.05 to 0.3% by weight for Cr and for Sc, 0.05 to 0.5% by weight for Hf and for V and from 0.01 to 0.15% by weight for Ti; other elements at most 0.05% by weight each and 0.15% by weight in total and the remainder being aluminum;
b) a crude fonn is cast from said liquid metal bath;
c) said crude form is homogenized at a temperature comprised between 450 C and 550 C and preferably between 480 C and 530 C for a period comprised between 5 and 60 hours;
d) said homogenized crude fonn is hot-worked, preferably by rolling;
e) the hot-worked product is solution heat-treated between 490 and 530 C for 15 min to 8 h and said solution heat-treated product is quenched;
f) said product is cold-worked with a working of 2 to 16%;
Date Reçue/Date Received 2020-10-09 g) ageing is carried out wherein said product reaches a temperature comprised between 130 and 170 C and preferably between 140 and 160 C for 5 to 100 hours and preferably 10 to 70 hours.
5 11. The product according to any one of claims 1 to 9 or can be obtained by the method according to claim 10, with a thickness comprised between 8 and 50 mm having, at mid-thickness:
i) a compressive yield strength Rcp0.2(L) > 590 MPa, preferably Rcpo.2(L) >
595 MPa;
ii) a toughness Kapp (L-T) > 60 MPa-Vm, preferably Kapp (L-T) > 75 MPa-Vm, with Kapp 10 (L-T) the value of the apparent stress intensity factor at rupture defined according to standard ASTM E561 (2015) measured on CCT test specimens of width W = 406 mm and thickness B = 6.35 mm;
iii) a difference between the tensile yield strength Rpo.2(L) and the compressive yield strength Rcpo.2(1_,), Rpo.2(L) - Rcpo.2(1_,), less than or equal to 10 MPa, preferably < 5 15 MPa.
12. An aircraft structure element, preferably an aircraft upper wing skin element, comprising a product according to any one of claims 1 to 9 or according to
b) a crude fonn is cast from said liquid metal bath;
c) said crude form is homogenized at a temperature comprised between 450 C and 550 C and preferably between 480 C and 530 C for a period comprised between 5 and 60 hours;
d) said homogenized crude fonn is hot-worked, preferably by rolling;
e) the hot-worked product is solution heat-treated between 490 and 530 C for 15 min to 8 h and said solution heat-treated product is quenched;
f) said product is cold-worked with a working of 2 to 16%;
Date Reçue/Date Received 2020-10-09 g) ageing is carried out wherein said product reaches a temperature comprised between 130 and 170 C and preferably between 140 and 160 C for 5 to 100 hours and preferably 10 to 70 hours.
5 11. The product according to any one of claims 1 to 9 or can be obtained by the method according to claim 10, with a thickness comprised between 8 and 50 mm having, at mid-thickness:
i) a compressive yield strength Rcp0.2(L) > 590 MPa, preferably Rcpo.2(L) >
595 MPa;
ii) a toughness Kapp (L-T) > 60 MPa-Vm, preferably Kapp (L-T) > 75 MPa-Vm, with Kapp 10 (L-T) the value of the apparent stress intensity factor at rupture defined according to standard ASTM E561 (2015) measured on CCT test specimens of width W = 406 mm and thickness B = 6.35 mm;
iii) a difference between the tensile yield strength Rpo.2(L) and the compressive yield strength Rcpo.2(1_,), Rpo.2(L) - Rcpo.2(1_,), less than or equal to 10 MPa, preferably < 5 15 MPa.
12. An aircraft structure element, preferably an aircraft upper wing skin element, comprising a product according to any one of claims 1 to 9 or according to
claim 11.
Date Reçue/Date Received 2020-10-09
Date Reçue/Date Received 2020-10-09
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
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| FR1853798A FR3080860B1 (fr) | 2018-05-02 | 2018-05-02 | Alliage aluminium cuivre lithium a resistance en compression et tenacite ameliorees |
| FR1853798 | 2018-05-02 | ||
| PCT/FR2019/050965 WO2019211547A1 (fr) | 2018-05-02 | 2019-04-24 | Alliage aluminium cuivre lithium a resistance en compression et tenacite ameliorees |
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| CA3096776A Pending CA3096776A1 (fr) | 2018-05-02 | 2019-04-24 | Aluminium-copper-lithium alloy having improved compressive strength and improved toughness |
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| US (1) | US20210310108A1 (fr) |
| EP (1) | EP3788178B1 (fr) |
| CN (1) | CN112041473A (fr) |
| BR (1) | BR112020021796B1 (fr) |
| CA (1) | CA3096776A1 (fr) |
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| CN114438382B (zh) * | 2021-11-17 | 2022-10-11 | 江阴沐祥精工科技有限公司 | 一种轨道铝型材 |
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| US5032359A (en) | 1987-08-10 | 1991-07-16 | Martin Marietta Corporation | Ultra high strength weldable aluminum-lithium alloys |
| US5455003A (en) | 1988-08-18 | 1995-10-03 | Martin Marietta Corporation | Al-Cu-Li alloys with improved cryogenic fracture toughness |
| US7438772B2 (en) | 1998-06-24 | 2008-10-21 | Alcoa Inc. | Aluminum-copper-magnesium alloys having ancillary additions of lithium |
| DE04753337T1 (de) | 2003-05-28 | 2007-11-08 | Alcan Rolled Products Ravenswood LLC, Ravenswood | Neue al-cu-li-mg-ag-mn-zr-legierung für bauanwendungen, die hohe festigkeit und hohe bruchzähigkeit erfordern |
| CN101855376B (zh) * | 2007-09-21 | 2013-06-05 | 阿勒里斯铝业科布伦茨有限公司 | 适于航空应用的Al-Cu-Li合金产品 |
| EP2231888B1 (fr) | 2007-12-04 | 2014-08-06 | Alcoa Inc. | Alliages d'aluminium-cuivre-lithium améliorés |
| FR2969177B1 (fr) | 2010-12-20 | 2012-12-21 | Alcan Rhenalu | Alliage aluminium cuivre lithium a resistance en compression et tenacite ameliorees |
| KR102003569B1 (ko) | 2011-02-17 | 2019-07-24 | 아르코닉 인코포레이티드 | 2xxx 계열 알루미늄 리튬 합금 |
| FR2989387B1 (fr) * | 2012-04-11 | 2014-11-07 | Constellium France | Alliage aluminium cuivre lithium a resistance au choc amelioree |
| US9458528B2 (en) | 2012-05-09 | 2016-10-04 | Alcoa Inc. | 2xxx series aluminum lithium alloys |
| FR3007423B1 (fr) * | 2013-06-21 | 2015-06-05 | Constellium France | Element de structure extrados en alliage aluminium cuivre lithium |
| CN103509984A (zh) | 2013-09-28 | 2014-01-15 | 中南大学 | 一种超高强铝锂合金及其制备方法 |
| FR3014905B1 (fr) * | 2013-12-13 | 2015-12-11 | Constellium France | Produits en alliage d'aluminium-cuivre-lithium a proprietes en fatigue ameliorees |
| US20150322556A1 (en) * | 2014-05-06 | 2015-11-12 | Goodrich Corporation | Lithium free elevated temperature aluminum copper magnesium silver alloy for forged aerospace products |
| RU2560485C1 (ru) * | 2014-06-10 | 2015-08-20 | Федеральное государственное унитарное предприятие "Всероссийский научно-исследовательский институт авиационных материалов" (ФГУП "ВИАМ") | Высокопрочный сплав на основе алюминия и изделие, выполненное из него |
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| EP3788178B1 (fr) | 2022-08-17 |
| US20210310108A1 (en) | 2021-10-07 |
| BR112020021796A2 (pt) | 2021-03-23 |
| CN112041473A (zh) | 2020-12-04 |
| FR3080860B1 (fr) | 2020-04-17 |
| FR3080860A1 (fr) | 2019-11-08 |
| EP3788178A1 (fr) | 2021-03-10 |
| BR112020021796B1 (pt) | 2024-01-09 |
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