Three-stage solution heat treatment method for Al-Zn-Mg-Cu system aluminum alloy

A heat treatment method and three-stage solid solution technology, which is applied in the field of heat treatment to improve the corrosion resistance of Al-Zn-Mg-Cu aluminum alloys, can solve the problems of affecting the aging strengthening effect and reducing the supersaturation of solid solution on the surface of alloy materials, etc.

Inactive Publication Date: 2010-01-13
CENT SOUTH UNIV
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  • Description
  • Claims
  • Application Information

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Problems solved by technology

In addition, high-temperature pre-precipitation will bring new problems in practical applications, that is, in the production process, the quenching of alloy materials requires transfer time. During the quenching transfer process, the temperature of the surface layer of alloy materials will be further reduced on the basis of the pre-precipitation temperature. , which causes more precipitated phases to precipitate in the grain and grain boundary of the surface layer of the alloy material, further reduces the supersaturation of the solid solution on the surface layer of the alloy material, and finally affects its aging strengthening effect

Method used

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  • Three-stage solution heat treatment method for Al-Zn-Mg-Cu system aluminum alloy
  • Three-stage solution heat treatment method for Al-Zn-Mg-Cu system aluminum alloy
  • Three-stage solution heat treatment method for Al-Zn-Mg-Cu system aluminum alloy

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Experimental program
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Effect test

Embodiment 1

[0020] The chemical composition of the experimental alloy is: Al-6.5Zn-2.4Mg-2.2Cu-0.13Zr (mass fraction). The solid solution adopts conventional solution treatment, that is, it is directly kept at 480°C for 3 hours and then quenched in water. The quenching transfer time is less than 5s, and the aging is carried out in two ways: peak aging (130°C / 24h) and tertiary aging (130°C / 24h→180°C / 1h→130°C / 24h). After the aging, the hardness and electrical conductivity tests were carried out, and the experimental results are shown in Table 1. The peak aged samples were then subjected to exfoliation corrosion ratings. The evaluation results are shown in Table 3.

Embodiment 2

[0022] The chemical composition of the experimental alloy is: Al-6.5Zn-2.4Mg-2.2Cu-0.13Zr (mass fraction). Solution treatment using three-stage solution heat treatment and high temperature pre-precipitation process comparison:

[0023] (1) Three-stage solution heat treatment: the sample is directly heated to 470 ° C for 1 h, then cooled to 380 ° C at a rate of 0.5 ° C / min and maintained for 0.5 h, then heated to 450 ° C at a rate of 5 ° C / min, and kept 2min.

[0024] (2) Solid solution-cooling precipitation (low temperature precipitation) treatment: the first stage adopts the same treatment method as the first stage of the three-stage solution heat treatment, and then cools down to 420°C at a rate of 0.5°C / min and holds for 30 minutes.

[0025] (3) High-temperature pre-precipitation (high-temperature precipitation) treatment: the first stage adopts the same treatment method as the first stage of the three-stage solution heat treatment, and then the temperature is lowered ...

Embodiment 3

[0028] The chemical composition of the experimental alloy is: Al-8.6Zn-2.5Mg-2.2Cu-0.16Zr (mass fraction). Solution treatment adopts three-stage solution heat treatment and high-temperature pre-precipitation process, and the specific implementation process is as follows:

[0029] (1) Three-stage solution heat treatment: heat up to 480°C with the furnace and hold for 2 hours, then cool down to 400°C at a rate of 1°C / min and hold for 5 hours, then raise the temperature to 470°C at a rate of 5°C / min, hold time for 5min.

[0030] (2) Solid solution-cooling precipitation (low temperature precipitation) treatment: the first stage adopts the same treatment method as the first stage of the three-stage solution heat treatment, and then cools down to 430°C at a rate of 0.5°C / min and holds for 30min.

[0031] (3) High-temperature pre-precipitation (high-temperature precipitation) treatment: the first stage adopts the same treatment method as the first stage of the three-stage solution h...

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Abstract

Disclosed is a three-stage solid solution heat treatment method of an Al-Zn-Mg-Cu family aluminum alloy. The Al-Zn-Mg-Cu family aluminum alloy three-stage solid solution heat treatment method comprises the following process steps: the solid solution temperature of the Al-Zn-Mg-Cu family aluminum alloy is between 470 to 490 DEG C, and the temperature is maintained for 1 to 4 hours to realize the solid solution; then, the alloy material temperature is reduced to 380 to 430 DEG C from the alloy material solid solution temperature at a cooling rate of 0.5 to 1.5 DEG C per minute, the alloy temperature is reduced and the precipitation is performed; thereafter, the temperature is increased to 450 to 480 DEG C at a cooling rate of 5 to 10 DEG C per minute, the temperature is maintained for 2 to 10 minutes, the alloy is taken from the furnace for water quenching. The invention has the advantages that the process method is simple, the operation is convenient, and when the alloy strength is retained, the corrosion resistance performance is enhanced, continuous operation is realizable, the method is suitable for industrial production, and can replace the existing Al-Zn-Mg-Cu family aluminum alloy enforced heat treatment method, and the aluminum alloy application field is widened.

Description

technical field [0001] The invention relates to a heat treatment method for improving the corrosion resistance of Al-Zn-Mg-Cu aluminum alloys, in particular to a three-stage solid solution heat treatment method for Al-Zn-Mg-Cu aluminum alloys. The invention relates to an aluminum alloy heat treatment process belonging to the field of metallurgy. Background technique [0002] Al-Zn-Mg-Cu series aluminum alloy is a high-strength aluminum alloy that can be strengthened by heat treatment, and the strength of the alloy can be improved by quenching and aging process. However, during the aging process, the precipitates on the grain boundaries are enriched and distributed continuously, which reduces the toughness and corrosion resistance of the alloy. In order to improve the toughness and corrosion resistance of alloys, people mainly use multi-stage aging process to adjust the distribution of precipitates in grains and grain boundaries. The dual-stage aging process of peak aging +...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22F1/04
Inventor 陈康华肖代红巢宏
Owner CENT SOUTH UNIV
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