An Aging Process for Improving the Microstructure and Properties of 7n01 Aluminum Alloy

A technology for improving the performance of aluminum alloys, which is applied in the field of aging technology to improve the microstructure and properties of 7N01 aluminum alloys. Mechanical properties, reducing stress corrosion susceptibility, and reducing the effect of heat treatment energy consumption

Active Publication Date: 2020-07-10
INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

After 7N01 aluminum alloy undergoes peak aging, the intragranular precipitates have the characteristics of fine dispersion and high number density, which makes the alloy have high mechanical properties. However, due to the continuous grain boundary precipitates in this state, the stress corrosion resistance of the alloy is sensitive. However, after the 7N01 aluminum alloy has undergone overaging treatment, the precipitates at the grain boundaries are distributed intermittently, and the alloy has good stress corrosion resistance, but the precipitates in the grain grow seriously, resulting in a significant decline in the mechanical properties of the alloy.
In contrast, the regression reaging treatment system can make the alloy have good stress corrosion resistance while maintaining high mechanical properties, but due to the short regression time at high temperature of the regression reaging treatment system, it is not suitable for the production of large aluminum alloy parts

Method used

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  • An Aging Process for Improving the Microstructure and Properties of 7n01 Aluminum Alloy
  • An Aging Process for Improving the Microstructure and Properties of 7n01 Aluminum Alloy
  • An Aging Process for Improving the Microstructure and Properties of 7n01 Aluminum Alloy

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Experimental program
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Effect test

Embodiment 1

[0026] In this embodiment, the implementation process of 7N01 aluminum alloy stress aging:

[0027] 1) The 7N01 aluminum alloy raw material is smelted in a resistance furnace. The designed 7N01 aluminum alloy composition is, in terms of element mass percentage, zinc: 4.13%, magnesium: 1.31%, manganese: 0.30%, chromium: 0.21%, zirconium: 0.10 %, titanium: 0.06%, the balance is aluminum and unavoidable impurities.

[0028] 2) The prepared 7N01 aluminum alloy ingot was heated to 470° C. in a box-type resistance furnace, kept for 24 hours, and then air-cooled to room temperature.

[0029] 3) The 7N01 aluminum alloy ingot was preheated at 450°C for 1 hour, and then extruded. The extrusion die temperature was 420°C, the extrusion speed was 10m / min, and the extrusion ratio was 22, and then water cooled to room temperature immediately.

[0030] 4) Naturally aging the extruded 7N01 aluminum alloy plate at room temperature for 60 days.

[0031] 5) The naturally aged 7N01 aluminum allo...

Embodiment 2

[0034] The difference from Example 1 is:

[0035] 1) The extruded 7N01 aluminum alloy plate was naturally aged at room temperature for 30 days.

[0036] 2) The naturally aged 7N01 aluminum alloy was kept at 150° C. for different times, and a tensile stress of 100 MPa was applied while keeping it warm.

[0037] The technical indicators of this embodiment are as follows: the hardness range is 98-117HV, the average long-axis size range of intragranular precipitated phases is 8-14nm, and the average precipitated phase number density range is 4100-4700 / μm 2 , The average width of the grain boundary precipitated phase ranges from 16 to 22 nm.

Embodiment 3

[0039] The difference from Example 1 is:

[0040] 1) The extruded 7N01 aluminum alloy plate was naturally aged for 90 days at room temperature.

[0041] 2) The naturally aged 7N01 aluminum alloy was kept at 170°C for different times, and a tensile stress of 75MPa was applied while keeping it warm.

[0042] The technical indicators of this embodiment are as follows: the hardness range is 101-127HV, the average long-axis size range of intragranular precipitates is 11-17nm, and the average precipitated phase number density range is 4000-5100 / μm 2 , The average width of the grain boundary precipitated phase ranges from 16 to 24 nm.

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Abstract

The invention relates to the field of production of aluminum alloys, in particular to an aging process for improving the 7N01 aluminum alloy structure and performance. Firstly, a 7N01 aluminum alloy which is in an extrusion state or in a rolled state and is subjected to solution treatment is subjected to natural aging treatment, then the 7N01 aluminum alloy is subjected to heat preservation at a certain temperature, and tensile stress is applied while heat preservation. Through the process, the aging separation process of the 7N01 aluminum alloy is improved. The applicable 7N01 aluminum alloycomponents comprise, by mass, 4.0-5.0% of zinc, 1.0-2.0% of magnesium, smaller than or equal to 0.20% of copper, 0.20-0.70% of manganese, smaller than or equal to 0.30% of chromium, smaller than or equal to 0.25% of zirconium, smaller than or equal to 0.20% of titanium, smaller than or equal to 0.10% of vanadium, and the balance aluminum and inevitable impurities. The tensile stress is added in the aging process, and by improving the matrix precipitate and grain boundary precipitate morphologies of the 7N01 aluminum alloy, the performance of the 7N01 aluminum alloy is remarkably improved.

Description

technical field [0001] The invention relates to the production field of aluminum alloys, in particular to an aging process for improving the microstructure and properties of 7N01 aluminum alloys. Background technique [0002] 7N01 aluminum alloy is an Al-Zn-Mg series medium-strength aluminum alloy for rail transit. This alloy extruded profile is mainly used for load-bearing parts such as traction beams, end beams and door columns of high-speed trains. The technological process of the alloy extrusion product mainly includes: alloy casting, homogenization, hot extrusion, on-line solid solution treatment, straightening and aging, etc. [0003] The aging process has a great influence on the mechanical properties and stress corrosion susceptibility of 7N01 aluminum alloy. After the peak aging of 7N01 aluminum alloy, the precipitated phase in the grain has the characteristics of fine dispersion and high number density, which makes the alloy have high mechanical properties, but be...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22F1/053C22C21/10
CPCC22C21/10C22F1/053
Inventor 姜海昌张舵戎利建付鸿闫德胜胡小锋赵明久宋元元
Owner INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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