Heat treatment method for improving comprehensive performance of alloy plate

Abstract

The invention provides a heat treatment method for improving the comprehensive performance of alloy. The alloy contains the following components of, by weight, 3.5%-4.5% of Cu, 1.4%-1.80% of Li, 0.2%-0.8% of Mg, 0.2%-0.8% of Zn, 0.04%-0.20% of Zr, 0.20%-0.80% of Mn, any one to three kinds of 0.05%-0.35% of Sc, 0.2%-0.8% of Ag and 0.10%-0.25% of Er, less than or equal to 0.08% of Si, less than or equal to 0.10% of Fe, less than or equal to 0.10% of Ti, less than or equal to 0.05% of other impurities individually, less than or equal to 0.15% of the other impurities in total, and the balance Al.The method comprises the following steps that after the alloy is subjected to solid solution and quenching, "spheroidizing aging" treatment is performed for 10 hours to 20 hours at 220 DEG C to 280 DEG C, the micron-scale granular precipitated phase is formed in the crystal, meanwhile, the large-size flake-and-needle-like "Widmanstatten structure" remained at the crystal boundary is converted intothe intermittent granular equilibrium phase, then repeated solid solution treatment, cold deformation treatment and aging treatment are performed, so that re-dissolution of the micron-scale granularprecipitated phase is achieved, moreover, precipitation of the nano-scale precipitated phase is promoted, the characteristic tissue with the uniform and tiny in-crystal precipitated phase and the intermittently-distributed crystal boundary precipitated phase is obtained, then the comprehensive performance of the alloy is improved, and the method is suitable for alloy thick plates, forge pieces andlarge-section extrusion materials used in the fields of aviation and weapons.

Description

technical field [0001] The invention relates to a heat treatment technology for alloys, in particular to a heat treatment method for improving the comprehensive properties of alloy plates. Background technique [0002] With the continuous development of high reliability and high weight reduction requirements in the aerospace field, alloys with lower density and higher strength are required, and the existing alloys are not competent in terms of strength level (500MPa) and density. In order to achieve this goal, moderately increase the content of some alloying elements, increase the degree of solid solution saturation of the alloy to obtain an alloy with higher strength and lower density. In the process of thermal deformation, it is easy to precipitate a large number of needle-like "Widmanstite (Al 2 CuLi, T 1 phase)” organization, the structure has a strong “hereditary” nature, which is difficult to eliminate in the subsequent solid solution and aging process, thus deterior...

AI Technical Summary

Problems solved by technology

[0002] With the continuous development of high reliability and high weight reduction requirements in the aerospace field, alloys with lower density and higher strength are required, and the existing alloys are not competent in terms of strength level (500MPa) and density

In order to achieve this goal, moderately increase the content of some alloying elements, increase the degree of solid solution saturation of the alloy to obtain an alloy with higher strength and lower density. In the process of thermal deformation, it is easy to precipitate a large number of needle-like "Widmanstite (Al 2 CuLi, T 1 phase)” organization, the structure has a strong “hereditary” nature, which is difficult to eliminate in the subsequent solid solution and aging process, thus deteriorating the performance of plasticity, fracture toughness, corrosion and other aspects, affecting the subsequent development and development of the alloy. application

[0003] Therefore, it is necessary to provide a technical solution for the problem that the "Widmansterite" structure in high-alloy content alloy products is difficult to eliminate, which affects the overall performance, to meet the needs of the existing technology

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