Method for improving stress corrosion resisting performance of aluminum lithium alloy

Abstract

The invention belongs to the aluminum lithium alloy heat treatment technology, in particular to a heat treatment technology capable of improving the stress corrosion resisting performance of an aluminum lithium alloy. Applicable alloy components of the technology comprise main alloying elements including, by weight percent, 0.5%-5.0% of Cu, 0.4%-2.5% of Li, 0.1%-4.0 % of Mg and 0.1%-4.0% of Zn, comprise microalloying elements including any one to four of, by weight percent, 0.04%-0.02% of Zr, 0.05%-0.60% of Sc, 0.20%-0.80% of Mn and 0.1%-0.9% of Ag and comprise, by weight percent, smaller than or equal to 0.10% of Si, smaller than or equal to 0.10% of Fe, smaller than or equal to 0.10% of Ti, smaller than or equal to 0.05% of each of other impurities and the balance Al, wherein the total amount of other impurities is smaller than or equal to 0.15%. After a deformed product is subjected to annealing treatment, cold deformation of a certain deformation amount is conducted, then solution hardening is conducted, regulation and control over the recrystallization degree and the grain boundary precipitates can be achieved through the manner, and other mechanical properties of the alloy are kept unchangeable while the stress corrosion resisting performance of the alloy is improved. The alloy preparing steps include annealing treatment, cold deformation treatment, solution treatment and ageing treatment. The technology is suitable for high-performance Al-Cu-Li-X series aluminum lithium alloy thick plates and forge pieces used in the fields of aviation, spaceflight and weapons.

Description

technical field [0001] The invention belongs to aluminum-lithium alloy heat treatment technology, in particular to a heat treatment process capable of improving the stress corrosion resistance performance of aluminum-lithium alloy. Background technique [0002] Al-Li alloys have attracted attention in the aerospace field due to their low density, high specific strength and specific stiffness. At present, Al-Mg-Li-X series and Al-Cu-Li-X series aluminum-lithium alloys are widely used. Thick plates and forgings are the main applications of these two types of Al-Li alloys. Due to the high recrystallization temperature of the alloy, it is difficult for the alloy to recrystallize during the hot working process and the subsequent solid solution process. Most of the grains are typical strip-shaped deformation structures, and the grain boundaries are straight. In the subsequent aging process, the precipitated phases are first precipitated at the grain boundaries to form continuous...

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Problems solved by technology

In the subsequent aging process, the precipitated phases are first precipitated at the grain boundaries to form continuous plates or granular precipitation belts. These grain boundary precipitates are first dissolved as anodic phases during the corrosion process. Under the action of corrosive environment and tensile stress, The alloy is easy to crack along the grain boundary, which greatly reduces the stress corrosion resistance of the alloy and affects the application range of the alloy

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