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CN-122013077-A - Heat treatment method for improving toughness of aluminum-lithium alloy plate

CN122013077ACN 122013077 ACN122013077 ACN 122013077ACN-122013077-A

Abstract

The invention belongs to the technical field of aluminum-lithium alloy heat treatment, and provides a heat treatment method for improving the toughness of an aluminum-lithium alloy plate. The heat treatment method comprises the steps of sequentially carrying out solution heat treatment, rolling pre-deformation treatment, pre-stretching treatment and artificial aging treatment on the aluminum-lithium alloy plate. The method comprises the steps of carrying out solution treatment on a second phase precipitated by a cold deformation state aluminum lithium alloy plate to obtain a supersaturated solid solution of the aluminum lithium alloy plate, carrying out rolling pre-deformation to introduce a large amount of dislocation, introducing work hardening to increase dislocation density, improving aging precipitation power of the aluminum lithium alloy plate, carrying out pre-stretching treatment to eliminate residual stress in the rolling pre-deformation process, obtaining the aluminum lithium alloy plate with stress relief and flat appearance, carrying out artificial aging treatment to separate out a large amount of T1 phases, theta' and other strengthening phases, realizing strengthening and toughening of the aluminum lithium alloy plate, and achieving yield strength of more than 520MPa, tensile strength of more than 590MPa and elongation of more than 8%.

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 (8)

  1. 1. The heat treatment method for improving the toughness of the aluminum-lithium alloy plate is characterized by comprising the following steps of: And sequentially carrying out solution heat treatment, rolling pre-deformation treatment, pre-stretching treatment and artificial aging treatment on the aluminum-lithium alloy plate.
  2. 2. The heat treatment method according to claim 1, wherein the aluminum-lithium alloy sheet is a cold-deformed aluminum-lithium alloy sheet, and the cold deformation is 60-84%.
  3. 3. The heat treatment method according to claim 1 or 2, wherein the aluminum-lithium alloy plate comprises, by mass, 3-4% of Cu, 0.75-1.5% of Li, 0.2-1% of Mg, 0.2-1% of Ag, 0.2-1% of Mn, 0.05-0.25% of Zr, less than 0.25% of impurities, and the balance of Al.
  4. 4. A heat treatment method according to claim 3, wherein the solution heat treatment is performed at a temperature of 525 to 545 ℃ for a time of 30 to 100 minutes.
  5. 5. The heat treatment method according to claim 4, wherein the deformation amount of the rolling pre-deformation treatment is 5 to 25%.
  6. 6. The heat treatment method according to claim 4 or 5, wherein the deformation amount of the pre-stretching treatment is 2.5 to 5%.
  7. 7. The heat treatment method according to claim 6, wherein the temperature of the artificial aging treatment is 150-200 ℃, and the time of the artificial aging treatment is 4-32 hours.
  8. 8. The heat treatment method according to claim 1 or 7, wherein the solution heat treatment is finished by water quenching and then rolling pre-deformation treatment is performed; the water quenching time is 1-2 min.

Description

Heat treatment method for improving toughness of aluminum-lithium alloy plate Technical Field The invention relates to the technical field of aluminum-lithium alloy heat treatment, in particular to a heat treatment method for improving the toughness of an aluminum-lithium alloy plate. Background The aluminum lithium alloy is an aluminum alloy added with lithium element, lithium (Li) is used as the lightest metal element, the density is only 0.534g/cm 3, and the addition of the lithium element into the aluminum alloy which is a light metal material can be called as light-up-light-up. Researches show that the density of the aluminum alloy can be reduced by 3 percent and the rigidity can be increased by 6 percent when 1 percent of Li element is added, and the original strength, corrosion resistance, fatigue resistance and ductility of the aluminum alloy are maintained. This makes aluminum-lithium alloys a very competitive structural material in the aerospace field since the 20 th century. To date, aluminum lithium alloys have been developed to the third generation, which has better comprehensive mechanical properties than the first generation aluminum lithium alloys with lower strength and the second generation aluminum lithium alloys with poor toughness and plasticity. The third generation aluminum-lithium alloy is an Al-Cu-Li alloy, is an alloy capable of strengthening 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 T1 phase (Al 2 CuLi), a theta 'phase (Al 2 Cu), a delta' phase (Al 3 Li) and the like. Of these, the T1 phase has the strongest strengthening effect, and its contribution to alloy strength is positively correlated with the volume fraction and diameter of the T1 phase. 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 strength of the aluminum-lithium alloy plate is generally limited to further application of the aluminum-lithium alloy plate in the related field due to the influence of the processing technology, the deformation and the like of the aluminum-lithium alloy plate. Therefore, research on a treatment process for improving the toughness of the aluminum-lithium alloy plate is needed to widen the application field of the aluminum-lithium alloy plate. Disclosure of Invention The invention aims to provide a heat treatment method for improving the toughness of an aluminum-lithium alloy plate, aiming at the defects in the prior art. In order to achieve the above object, the present invention provides the following technical solutions: the invention provides a heat treatment method for improving the toughness of an aluminum-lithium alloy plate, which comprises the following steps: And sequentially carrying out solution heat treatment, rolling pre-deformation treatment, pre-stretching treatment and artificial aging treatment on the aluminum-lithium alloy plate. Preferably, the aluminum-lithium alloy plate is a cold deformation aluminum-lithium alloy plate, and the cold deformation amount is 60-84%. Preferably, the aluminum-lithium alloy plate comprises, by mass, 3-4% of Cu, 0.75-1.5% of Li, 0.2-1% of Mg, 0.2-1% of Ag, 0.2-1% of Mn, 0.05-0.25% of Zr, less than 0.25% of impurities and the balance of Al. Preferably, the temperature of the solution heat treatment is 525-545 ℃ and the time of the solution heat treatment is 30-100 min. Preferably, the deformation amount of the rolling pre-deformation treatment is 5-25%. Preferably, the deformation amount of the pre-stretching treatment is 2.5-5%. Preferably, the temperature of the artificial aging treatment is 150-200 ℃, and the time of the artificial aging treatment is 4-32 h. Preferably, after the solution heat treatment is finished, water quenching is performed first, and then rolling pre-deformation treatment is performed; the water quenching time is 1-2 min. The invention has the beneficial effects that: The method comprises the steps of carrying out solution treatment on a second phase separated out from a cold deformation state aluminum lithium alloy plate by optimization, carrying out solution treatment on the second phase separated out from the cold deformation state aluminum lithium alloy plate to obtain a supersaturated solid solution of the aluminum lithium alloy plate, carrying out rolling pre-deformation to introduce dislocation in a large amount, introducing work hardening to increase dislocation density, improving aging precipitation power of the aluminum lithium alloy plate, carrying out pre-stretching treatment to eliminate residual stress in the rolling pre-deformation process, obtaining the aluminum lithium alloy plate with stress relief and flat appearance, carrying out artificial aging treatment to separate out a large number of T1 phases and theta' equal strengthening ph