Thermal treatment process for high-strength anticorrosion aluminum alloy

A corrosion-resistant and alloyed technology, applied in the field of heat treatment of aluminum alloy materials, can solve problems such as discontinuous distribution, poor corrosion resistance, and strength decline, and achieve the effects of prolonging the regression time, simplifying the operation process, and reducing the regression temperature

Active Publication Date: 2016-09-21
BEIJING UNIV OF TECH
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Problems solved by technology

The strength of 7xxx aluminum alloy T6 aging treatment is the highest, but its corrosion resistance is poor; the double-stage overaging treatment (T7X) improves the corrosion resistance of the alloy, but the strength of the alloy decreases by 10-15%
In order to improve the corrosion resistance of the alloy while taking into account the strength, Cina proposed a three-stage aging (RRA) heat treatment process. The alloy treated by this process has a large number of dispersed fine η 、 phase and a small amount of GP area, similar to the intragranular structure in the peak aging state; the discontinuous distribution of coarse precipitated phases at the grain boundary is similar to the grain boundary structure in the overaging state; for this reason, RRA heat treatment improves the mechanical properties while taking into account the Corrosion resistance, but due to the short regression time of the conventional RRA heat treatment process at high temperature, it is not conducive to industrial production
Moreover, the conventional RRA heat treatment process is directly held at a certain temperature for a period of time, lacking a slow temperature rise process, which is not conducive to the production of large and thick components; in addition, the conventional RRA heat treatment needs to be quenched in water after the first stage. Then perform regression processing, which increases the difficulty of the production process and is not close to the actual production process

Method used

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  • Thermal treatment process for high-strength anticorrosion aluminum alloy
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  • Thermal treatment process for high-strength anticorrosion aluminum alloy

Examples

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Effect test

Embodiment 1

[0029] The Al-7.2Zn-2.3Mg-0.6Cu-0.3Mn-0.1Er-0.1Zr alloy after hot extrusion deformation was raised from room temperature to 470 °C for 4 hours, then kept for 2 hours, and then water quenched immediately; then aging heat treatment was performed , the first-stage aging heat treatment process is to increase the alloy obtained after solution-water quenching from room temperature to 120 °C at a heating rate of 50-70 °C / h, and then keep it for 24 hours; the second-stage heat treatment process is the first-stage aging. The obtained alloy is directly heated from 120°C to 190°C at a heating rate of 50-70°C / h in the furnace, then kept for 40 minutes, and then cooled to room temperature; the third-stage heat treatment process is that the alloy obtained after the second-stage heat treatment is The heating rate of 50-70°C / h was raised from room temperature to 120°C, then kept for 24h, and then cooled to room temperature. After aging treatment, exfoliation corrosion and tensile properties w...

Embodiment 2

[0031] The Al-7.2Zn-2.3Mg-0.6Cu-0.3Mn-0.1Er-0.1Zr alloy after hot extrusion deformation was raised from room temperature to 470 °C for 4 hours, then kept for 2 hours, and then water quenched immediately; then aging heat treatment was performed , the first-stage aging heat treatment process is to increase the alloy obtained after solution-water quenching from room temperature to 120 °C at a heating rate of 50-70 °C / h, and then keep it for 24 hours; the second-stage heat treatment process is the first-stage aging. The obtained alloy is directly heated from 120°C to 190°C with a heating rate of 50-70°C / h in the furnace, then kept for 60 minutes, and then cooled to room temperature; the third-stage heat treatment process is that the alloy obtained after the second-stage heat treatment is The heating rate of 50-70°C / h was raised from room temperature to 120°C, then kept for 24 hours, and then cooled to room temperature. After aging treatment, exfoliation corrosion and tensile prope...

Embodiment 3

[0033]Heat the Al-7.2Zn-2.3Mg-0.6Cu-0.3Mn-0.1Er-0.1Zr alloy after hot extrusion deformation from room temperature to 470°C in 4 hours, then keep it warm for 2 hours, and immediately perform water quenching; then perform aging heat treatment , the first-stage aging heat treatment process is to raise the alloy obtained after solid solution-water quenching from room temperature to 120°C at a rate of 50-70°C / h, and then keep it for 24h; the second-stage heat treatment process is the first-stage aging The processed alloy is directly raised from 120°C to 180°C at a heating rate of 50-70°C / h with the furnace, then kept for 60 minutes, and then cooled to room temperature; the third-level heat treatment process is the alloy obtained after the second-level heat treatment. The heating rate was 50-70°C / h from room temperature to 120°C, then kept for 24 hours, and then cooled to room temperature. After aging treatment, exfoliation corrosion and tensile performance tests were carried out ac...

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Abstract

The invention provides a thermal treatment process for a high-strength anticorrosion aluminum alloy and belongs to the technical field of thermal treatment of aluminum alloy materials. The thermal treatment process includes the following specific steps that the aluminum alloy deformed through hot extrusion is subjected to low-speed temperature-rising solution treatment and then subjected to three-level aging treatment; in the three-level aging process, the temperature rises to 120 DEG C from the room temperature at the temperature rising speed of 50 DEG C / h to 70 DEG C / h, and then the temperature is kept for 24 hours; then the temperature rises to 170 DEG C to 190 DEG C from 120 DEG C at the temperature rising speed of 50 DEG C / h to 70 DEG C / h with a furnace, then the temperature is kept for 40 min to 120 min, and then the alloy is cooled to the room temperature; and finally, the temperature of the obtained alloy rises to 120 DEG C from the room temperature at the temperature rising speed of 50 DEG C / h to 70 DEG C / h, then the temperature is kept for 24 hours, and then the alloy is cooled to the room temperature. By the adoption of the thermal treatment process, the anticorrosion performance of the alloy is improved on the premise of guaranteeing the strength, low-speed temperature rising in the solution and aging processes is more beneficial to diffusion of atoms, the purpose that large thick components are uniformly heated is more easily achieved, and the thermal treatment process is more suitable for industrial production.

Description

technical field [0001] The invention relates to a heat treatment process of a high-strength and corrosion-resistant Al-7.2Zn-2.3Mg-0.6Cu-0.3Mn-0.1Er-0.1Zr alloy, which belongs to the technical field of heat treatment of aluminum alloy materials. Background technique [0002] As a high-strength aluminum alloy, 7xxx series aluminum alloys are widely used in aerospace industry, transportation and other industries. 7xxx series aluminum alloys have the highest strength when T6 aging treatment, but their corrosion resistance is poor; double-stage overaging treatment (T7X) improves the corrosion resistance of the alloy, but the strength of the alloy decreases by 10-15%. In order to improve the corrosion resistance of the alloy while taking into account the strength, Cina proposed a three-stage aging (RRA) heat treatment process. The alloy treated by this process has a large number of finely dispersed η distributed in the grain. 、 Phase and a small amount of GP region are similar t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22F1/053C22C21/10
CPCC22C21/10C22F1/053
Inventor 黄晖卢军太聂祚仁高坤元文胜平吴晓蓝吴浩
Owner BEIJING UNIV OF TECH
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