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CN-122013009-A - High-strength and high-toughness aluminum lithium alloy plate and preparation method thereof

CN122013009ACN 122013009 ACN122013009 ACN 122013009ACN-122013009-A

Abstract

The invention provides a high-toughness aluminum-lithium alloy plate and a preparation method thereof, belonging to the technical field of metal materials and metallurgy. According to the invention, through scientifically proportioned alloy elements and a precise smelting process, most casting defects are eliminated through hot rolling deformation, enough processing strengthening is obtained through cold rolling deformation, and then two sections of pre-deformation is carried out on the aluminum lithium alloy plate subjected to solution treatment, so that the dislocation density is increased, the aging precipitation power of the alloy is remarkably improved, a large amount of tiny dispersed T 1 (Al 2 CuLi) phases and theta' (Al 2 Cu) equal strengthening phases are precipitated in the aging process, the strength and toughness of the aluminum lithium alloy are effectively improved, the high-strength and toughness aluminum lithium alloy plate with stress relief and smooth appearance is obtained, the yield strength can reach 520-560 MPa, the tensile strength can reach 580-630 MPa, and the elongation is 8-12%, and the use requirement of high-standard aerospace structural materials can be met.

Inventors

  • ZENG XIAOPENG
  • WU GUOHUA
  • TONG XIN
  • ZHANG LIANG

Assignees

  • 宜春赣锋锂业有限公司
  • 上海交通大学

Dates

Publication Date
20260512
Application Date
20260228

Claims (10)

  1. 1. The high-strength and high-toughness aluminum-lithium alloy plate is characterized in that the chemical composition is ：Cu 3.3~3.7%、Li 1.0~1.2%、Mg 0.3~0.5%、Mn 0.2~0.6%、Zn 0.2~0.4%、Ag 0.2~0.4%、Zr 0.08~0.12%、Ti 0.08~0.12%, impurities which are less than 0.1 percent and the balance is Al in percentage by mass; The preparation method of the high-strength and high-toughness aluminum lithium alloy plate comprises the following steps: Mixing the raw materials corresponding to the chemical components, sequentially smelting and refining, and adding a covering agent to obtain an alloy liquid; Casting and forming the alloy liquid to obtain an ingot; Homogenizing the cast ingot to obtain an alloy plate blank; carrying out hot rolling deformation on the alloy plate blank, and then carrying out annealing treatment to obtain an annealed alloy; Carrying out cold rolling treatment on the annealed alloy, and carrying out solution treatment to obtain a solution state alloy; and (3) carrying out pre-deformation treatment and aging treatment on the solid solution state alloy to obtain the high-strength and high-toughness aluminum-lithium alloy plate.
  2. 2. The method for preparing the high-strength and high-toughness aluminum-lithium alloy plate as claimed in claim 1, which is characterized by comprising the following steps: Mixing the raw materials corresponding to the chemical components, sequentially smelting and refining, and adding a covering agent to obtain an alloy liquid; Casting and forming the alloy liquid to obtain an ingot; Homogenizing the cast ingot to obtain an alloy plate blank; carrying out hot rolling deformation on the alloy plate blank, and then carrying out annealing treatment to obtain an annealed alloy; Carrying out cold rolling treatment on the annealed alloy, and carrying out solution treatment to obtain a solution state alloy; and (3) carrying out pre-deformation treatment and aging treatment on the solid solution state alloy to obtain the high-strength and high-toughness aluminum-lithium alloy plate.
  3. 3. The method of claim 2, wherein the feedstock comprises Al, al-Cu master alloy, al-Mn master alloy, al-Zr master alloy, al-Ti master alloy, zn, ag, mg and Li.
  4. 4. The method according to claim 2 or 3, wherein the refining agent used in the refining is argon or hexachloroethane, and the covering agent is any two or three of LiCl, liF, KCl, naCl.
  5. 5. The method according to claim 2, wherein the casting is performed at a temperature of 700-740 ℃ or continuously, and the molded shape is a rectangular parallelepiped.
  6. 6. The preparation method according to claim 2, wherein the homogenization treatment comprises sequentially performing a first-stage homogenization and a second-stage homogenization, wherein the temperature of the first-stage homogenization is 460-480 ℃ for 8-12 hours, and the temperature of the second-stage homogenization is 520-540 ℃ for 12-16 hours.
  7. 7. The preparation method according to claim 2, wherein the temperature of the hot rolling deformation is 440-480 ℃, the total deformation amount is 60-80%, the temperature of the annealing treatment is 530-545 ℃ and the time is 30-90 min.
  8. 8. The preparation method according to claim 2, wherein the cold rolling treatment is performed at a temperature of 20-25 ℃, the total deformation is 60-84%, the solid solution treatment is performed at a temperature of 525-545 ℃ for 30-100 min.
  9. 9. The preparation method according to claim 2, wherein the pre-deformation treatment comprises a first-stage cold deformation and a second-stage cold deformation which are sequentially performed, the first-stage cold deformation is pre-rolling, the deformation amount is 5-25%, the treatment temperature is 20-25 ℃, the second-stage cold deformation is pre-stretching, the deformation amount is 2.5-5%, and the treatment temperature is 20-25 ℃.
  10. 10. The method according to claim 2, wherein the aging treatment is performed at a temperature of 150-200 ℃ for a time of 4-32 hours.

Description

High-strength and high-toughness aluminum lithium alloy plate and preparation method thereof Technical Field The invention relates to the technical field of metal materials and metallurgy, in particular to a high-strength and high-toughness aluminum-lithium alloy plate and a preparation method thereof. Background Aluminum lithium alloy refers to an alloy in which lithium metal is added to aluminum or an aluminum alloy which is a light metal material, lithium (Li) is used as the lightest metal element in existence, and the addition of lithium element to an aluminum alloy is called "light-up-light-up". The prior report shows that the aluminum-lithium alloy is used for replacing the conventional aluminum alloy, so that the weight of the component is reduced by 10-15%, the rigidity is improved by 15-20%, and meanwhile, the component can ensure better strength, corrosion resistance, fatigue resistance and ductility similar to those of the conventional aluminum alloy material, the aluminum lithium alloy is rapidly developed and gradually replaces the traditional 2 XX and 7 XX aluminum alloy, and is widely applied to structural materials in the aerospace field. The development of the aluminum-lithium alloy is carried out in three times, which corresponds to the three-generation aluminum-lithium alloy products respectively, and compared with the problems of low strength of the first-generation alloy, poor toughness and plasticity of the second-generation alloy and the like, the third-generation aluminum-lithium alloy has better comprehensive mechanical properties. The third generation aluminum-lithium alloy is an Al-Cu-Li alloy, is an alloy capable of being strengthened by ageing, and is mainly strengthened by a second phase precipitated in an artificial ageing process, wherein the main ageing precipitation strengthening phases comprise a T 1 phase (Al 2 CuLi), a theta 'phase (Al 2 Cu), a delta' phase (Al 3 Li) and the like. Wherein the strengthening effect of the T 1 phase is the strongest, and the contribution of the T 1 relative alloy strength is positively correlated with the volume fraction and the diameter of the T 1 phase. Alloying, processing strengthening, age hardening and the like are effective methods for changing the types and the distribution of precipitated phases of the aluminum-lithium alloy, and are also main means for realizing the strengthening and the toughening of the aluminum-lithium alloy. However, in the prior art, the alloy processing methods disclosed in the patents of publication nos. CN108823519 a and CN108330360 a are extrusion deformation, and the most commonly used plates in the aeronautical structural materials are limited by the deformation methods, so that the strength of the extrusion deformation alloy is difficult to achieve. With the continuous development of the aerospace industry, higher requirements are put on the toughness of the aluminum-lithium alloy, particularly the aluminum-lithium alloy plate, and the aluminum-lithium alloy plate is limited by alloy components, preparation process, deformation and the like, so that the aluminum-lithium alloy plate is prevented from being further applied to the related fields. Disclosure of Invention The invention aims to provide a high-strength and high-toughness aluminum lithium alloy plate and a preparation method thereof, wherein alloy elements and a smelting process are scientifically proportioned, aluminum lithium alloy cast ingots with excellent performance are smelted, most casting defects are eliminated through hot rolling deformation, then enough processing strengthening is obtained through cold rolling deformation, the aluminum lithium alloy plate subjected to solution treatment is subjected to pre-deformation, dislocation density is increased, aging precipitation power of the alloy is obviously improved, a large amount of precipitation strengthening phases are effectively improved in the aging process, and the strength and toughness of the aluminum lithium alloy plate with stress relief and smooth appearance can be obtained. In order to achieve the above object, the present invention provides the following technical solutions: The invention provides a high-strength and toughness aluminum-lithium alloy plate, which comprises ：Cu 3.3~3.7%、Li 1.0~1.2%、Mg 0.3~0.5%、Mn 0.2~0.6%、Zn 0.2~0.4%、Ag 0.2~0.4%、Zr 0.08~0.12%、Ti 0.08~0.12%, percent of impurities <0.1 percent by mass and the balance of Al; The preparation method of the high-strength and high-toughness aluminum lithium alloy plate comprises the following steps: Mixing the raw materials corresponding to the chemical components, sequentially smelting and refining, and adding a covering agent to obtain an alloy liquid; Casting and forming the alloy liquid to obtain an ingot; Homogenizing the cast ingot to obtain an alloy plate blank; carrying out hot rolling deformation on the alloy plate blank, and then carrying out annealing treatment to obtain an annealed alloy; Carrying out