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CN-122029297-A - Aluminum-copper-lithium alloy product with improved properties for lower skin elements of an airfoil

CN122029297ACN 122029297 ACN122029297 ACN 122029297ACN-122029297-A

Abstract

The invention relates to a novel product made of aluminum-copper-lithium alloy and a preparation method thereof. The product is a rolled product having a final thickness of 15 mm to 50 mm and a composition (in weight%) ：Cu：2.3-2.7;Li：1.3-1.7;Mg：0.2-0.5;Mn：0.2-0.5;Ag：0-0.1;Zn：<0.20;Ti：0.01-0.15;Zr：<0.07;Fe：≤0.1;Si：≤0.1; of the other elements each being 0.05 or less and totaling 0.15 or less, the balance being aluminum, and wherein the sum of the volume fractions of Cube {001} <100>, goss {011} <100> and CG26.5 {021} <100> texture components at the intermediate thickness is less than or equal to 7.5%. The product may be prepared by hot rolling, wherein the thickness reduction of each of the last two passes is less than or equal to 10 mm, and wherein the final hot rolling temperature is from 400 ℃ to 440 ℃.

Inventors

  • E. Nizeri
  • M. Belawaan

Assignees

  • 伊苏瓦尔肯联铝业

Dates

Publication Date
20260512
Application Date
20240919
Priority Date
20231016

Claims (10)

  1. 1. A method of manufacturing a rolled product made of an aluminum copper lithium alloy, wherein: (a) Casting a slab made of an aluminum alloy having the composition, in weight-%: Cu: 2.3-2.7 Li: 1.3-1.7 Mg: 0.2-0.5 Mn: 0.2-0.5 Ag is 0-0.1, preferably less than or equal to 0.05 Zn is < 0.20, preferably equal to or less than 0.05 Ti: 0.01-0.15 Zr < 0.07, preferably equal to or less than 0.05 Fe: ≤ 0.1 Si: ≤ 0.1 The total of other elements is less than or equal to 0.05 and less than or equal to 0.15, the balance is aluminum, (B) Homogenizing the cast slab at a temperature of 480 to 540 ℃ for 5 to 60 hours, (C) Optionally, preheating the homogenized slab to 420 ℃ to 520 ℃, (D) Hot rolling the homogenized slab to obtain a rolled product having a final thickness of 15 mm to 50 mm, (E) Subjecting the rolled product to a solution heat treatment, preferably by heat treatment at 490 to 530 ℃ for 15 minutes to 8 hours, (F) Quenching the solution heat treated rolled product with water, (G) Subjecting said solution heat treated and quenched rolled product to controlled stretching, with a permanent set of 2% to 5%, (H) The thus solution heat treated, quenched and drawn rolled product is subjected to aging treatment by heating at 120 to 170 ℃ for 5 to 100 hours, It is characterized in that The hot rolling is performed according to N successive passes such that the thickness reduction of each of the last two passes is less than or equal to 10 mm, and wherein the final hot rolling temperature is from 400 ℃ to 440 ℃.
  2. 2. The manufacturing method according to claim 1, such that the thickness reduction of each of the last two passes is at least 1 mm, preferably at least 3 mm.
  3. 3. The manufacturing method according to claim 1 or 2, such that the average thickness reduction of the last three passes is less than or equal to 10 mm.
  4. 4. A manufacturing method according to any one of claims 1 to 3, such that the hot rolling inlet temperature is 420 to 520 ℃, preferably 450 to 480 ℃.
  5. 5. A rolled product having a thickness of 15 mm to 50 mm made of an aluminum copper lithium alloy having a composition in weight percent of: Cu: 2.3-2.7 Li: 1.3-1.7 Mg: 0.2-0.5 Mn: 0.2-0.5 Ag: 0-0.1 Zn: < 0.20 Ti: 0.01-0.15 Zr: < 0.07 Fe: ≤ 0.1 Si: ≤ 0.1 the total of other elements is less than or equal to 0.05 and less than or equal to 0.15, the balance is aluminum, Characterized in that the sum of the volume fractions of Cube {001} <100>, goss {011} <100> and CG26.5 {021} <100> texture components at intermediate thicknesses is less than or equal to 7.5%, preferably less than or equal to 7%, wherein the texture components are quantified using local measurements by electron back scattering diffraction and using a tolerance of 15 ° for each orientation selected.
  6. 6. Rolled product according to claim 5, characterized in that the Zr content is less than or equal to 0.05 wt%, preferably less than or equal to 0.04 wt%.
  7. 7. The rolled product according to claim 5 or 6, characterized in that the Ag content is less than or equal to 0.05 wt%.
  8. 8. Rolled product according to any of claims 5 to 7, characterized in that the Zn content is less than or equal to 0.05 wt%.
  9. 9. Rolled product according to any of claims 5 to 8, characterized in that at intermediate thickness the grain structure of the product is moderately recrystallized, the recrystallized grain area fraction of the grain structure being 20 to 50%, wherein the recrystallized area fraction is measured by EBSD, and wherein a grain is considered recrystallized if the grain has a difference in orientation from an adjacent grain of at least 11 ° and the grain orientation has an extension of less than 3 °, also known as grain orientation extension (GOS).
  10. 10. Rolled product according to any of claims 5 to 9, characterized by a T8 state.

Description

Aluminum-copper-lithium alloy product with improved properties for lower skin elements of an airfoil Technical Field The present invention relates to products made of aluminium alloys, and more particularly to such products, methods of manufacture and use thereof, particularly for use in the aerospace industry, preferably for use in under-wing skin applications. Background Rioja et al in "The role of crystallographic texture on the performance of flat rolled aluminum products for aerospace applications"——Light metals 2008 demonstrate that fatigue crack propagation resistance of 2x 24 or 2199 alloys under spectral loading decreases with increasing yield strength. Prasad et al in Aluminum-Lithium Alloys-Processing Properties and Applications-Elsevier 2014, chapter 11, pages 341-375, mention that improvement in fatigue properties of lithium alloys is achieved by solid solution hardening and coalescence of the delta' precipitate phases. Fatigue can also be improved by heat and thermo-mechanical treatments involving ageing (also known as artificial ageing) and pre-stretching or cold working before ageing. EP3077559 discloses a method of manufacturing rolled or wrought material having a thickness of 14 to 100 mm for use in lower wing skin applications. The material consists of an aluminium alloy consisting of ()：1.8-2.6 Cu;1.3-1.8 Li;0.1-0.5 Mg;0.1-0.5% Mn;Zr < 0.05;0-0.5 Ag;Zn < 0.20;0.01-0.15 Ti;Fe < 0.1%;Si < 0.1; in wt.% of the other elements each < 0.05 and total < 0.15, balance aluminium, with a density of less than 2.670 g/cm 3. The method comprises a homogenisation treatment; hot rolling at a final temperature of at least 400 ℃, preferably by heat treatment between 490 and 530 ℃ for 15 minutes to 8 hours, then solution heat treatment, usually quenched with water. The sheet is subsequently subjected to controlled stretching of 1% to 6% and then ageing at a temperature of 120 to 170 ℃ for 5 to 100 hours. There is a need to improve the fatigue properties of such products under spectral loading while maintaining their mechanical tensile properties and their toughness. Disclosure of Invention One object of the present invention relates to a manufacturing method that improves the fatigue properties under spectral load of rolled products made of lithium aluminum copper with a thickness of 15mm to 50 mm. The manufacturing method comprises the following steps: (a) Casting a slab made of an aluminum alloy having the composition, in weight-%: Cu: 2.3 - 2.7 Li: 1.3 - 1.7 Mg: 0.2 - 0.5 Mn: 0.2 - 0.5 ag is 0-0.1, preferably less than or equal to 0.05 Zn is < 0.20, preferably equal to or less than 0.05 Ti: 0.01 - 0.15 Zr < 0.07, preferably equal to or less than 0.05 Fe: ≤ 0.1 Si: ≤ 0.1 The total of other elements is less than or equal to 0.05 and less than or equal to 0.15, the balance is aluminum, (B) Homogenizing the cast slab at a temperature of 480 to 540 ℃ for 5 to 60 hours, (C) Optionally, preheating the homogenized slab to 420 ℃ to 520 ℃, (D) The homogenized slab (optionally preheated) is hot rolled to give a rolled product with a final thickness of 15 mm to 50 mm. The hot rolling is performed in N successive passes such that the thickness reduction of each of the last two passes is less than or equal to 10 mm. Preferably, the thickness reduction of each of the last two passes is at least 1mm, preferably at least 3 mm. Preferably, the average thickness reduction of the last three passes is less than or equal to 10 mm. The final hot rolling temperature is 400 ℃ to 440 ℃. Preferably, the hot rolling inlet temperature is from 420 ℃ to 520 ℃, preferably from 450 ℃ to 480 ℃. (E) Subjecting the rolled product to a solution heat treatment, preferably by heat treatment at 490 to 530 ℃ for 15 minutes to 8 hours, (F) Quenching the solution heat treated rolled product with water, (G) Subjecting said solution heat treated and quenched rolled product to controlled stretching, with a permanent set of 2 to 5%, (H) The thus solution heat treated, quenched and drawn rolled product is subjected to aging treatment by heating at 120 to 170 ℃ for 5 to 100 hours. Another object of the invention relates to a rolled aluminium copper lithium product having a thickness of 15 mm to 50 mm, the composition in% by weight being: Cu: 2.3 - 2.7 Li: 1.3 - 1.7 Mg: 0.2 - 0.5 Mn: 0.2 - 0.5 Ag: 0 - 0.1, Zn: < 0.20, Ti: 0.01 - 0.15 Zr: < 0.07, Fe: ≤ 0.1 Si: ≤ 0.1 the total of other elements is less than or equal to 0.05 and less than or equal to 0.15, and the balance is aluminum. The product is characterized in that the sum of the volume fractions of Cube {001} <100>, goss {011} <100> and CG26.5 {021} <100> texture components at intermediate thicknesses is less than or equal to 7.5%, preferably less than or equal to 7%. The texture component was quantified using local measurement by electron back-scattering diffraction and using a tolerance of 15 ° for each orientation selected. The state of the product is T8. The product is obtainable by the process