Method for preparing aluminum lithium alloy superplastic plate

Abstract

The invention discloses a method for preparing an aluminum lithium alloy superplastic plate. The process route of the method comprises the following steps: carrying out solid solution on a raw material, namely a 2A97 aluminum lithium alloy plate blank with certain initial thickness at 460-540 DEG C for 0.5-4 hours, carrying out water quenching, and then carrying out heat preservation at 400 DEG C for 8-48 hours; then rolling an alloy to 1.0-4.0 mm. Compared with the traditional thermomechanical treatment method, the method disclosed by the invention can be used for effectively solving the problem of easiness for cracking of a large-sized plate during rolling by increasing the intermediate annealing temperature, enhancing the deformation stored energy of the alloy and solving the problem of low superplastic elongation percentage of a plate by changing the traditional warm rolling process into a cold rolling process by retaining 20%-30% of deformation amount and can be used for firstly preparing the 2A97 aluminum lithium alloy large-sized superplastic plate with good superplastic property.

Description

technical field [0001] The invention belongs to the field of nonferrous metal material processing, and in particular relates to a method for preparing aluminum-lithium alloy superplastic plates. [0002] By adopting the method of the invention, the 2A97 aluminum-lithium alloy superplastic plate can be obtained, and the typical superplastic elongation rate is 560%-1070%. Background technique [0003] In the aerospace industry, reducing weight and increasing efficiency is an eternal theme. Every gram of weight reduction in the aircraft will produce considerable technical and economic benefits. 2A97 aluminum-lithium alloy is a new type of Al-Cu-Li alloy independently developed by my country. It belongs to the third generation of aluminum-lithium alloy and is an important lightweight structural material in the aerospace field. The modern aerospace industry requires lightweight, low-cost, and high-volume components. Applying superplastic technology to aluminum-lithium alloys c...

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Problems solved by technology

[0005] (1) The existing process requires a short residence time between rolling passes, otherwise the plate is easy to crack during rolling, and it is only suitable for preparing small-sized samples on small-scale rolling in the laboratory

For example, when preparing 2A97 aluminum-lithium alloy superplastic plates under industrial equipment conditions, after preheating at 400°C for 1 hour, when rolling from 25 mm thick to 10 mm thick, when the rolling deformation is only 60%, the plate will appear serious. cracking, such as figure 1 As shown, it is impossible to continue rolling

This is mainly due to the slow adjustment of the roll gap of the large rolling mill and the excessive temperature drop of the sample due to the long stay

[0006] (2) The method of multi-pass turning rolling is difficult to be used in the preparation of large-size plates

[0007] (3) The use of intermediate annealing can solve the problem of sheet rolling cracking. In the existing process, the intermediate annealing temperature must be lower than 300°C to obtain a sheet with a superplastic elongation rate of more than 350%. The lower annealing temperature increases the cracking of the sheet. Tendency

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