CN-122013003-A - 5-Series aluminum alloy and strengthening method thereof

Abstract

A5-series aluminum alloy and a strengthening method thereof relate to the technical field of aluminum alloy, wherein the 5-series aluminum alloy comprises 2.4-8.6% of Mg, the balance of Al and unavoidable impurities in percentage by mass; the invention also provides a method for strengthening the 5-series aluminum alloy, which comprises the following steps of S1, processing the 5-series aluminum alloy to obtain an alloy sample, S2, carrying out solution treatment on the alloy sample obtained in S1, quenching at room temperature, and S3, carrying out cyclic plastic treatment on the alloy sample quenched in S2 to obtain the strengthened 5-series aluminum alloy.

Inventors

• TAN JUN
• CHEN XIANHUA
• TANG AITAO
• PAN FUSHENG
• YANG RUI
• REN YULONG
• Ran Chunhua
• FAN ZHENGLIN
• ZUO YANG
• ZHANG QIN
• ZHANG LU
• Jie Xiaoying

Assignees

• 重庆大学

Dates

Publication Date

20260512

Application Date

20260415

Claims (10)

1. 1. A5-series aluminum alloy is characterized by comprising, by mass, 2.4-8.6% of Mg, and the balance of Al and unavoidable impurities.
2. 2. The method for strengthening a 5-series aluminum alloy according to claim 1, comprising the steps of: s1, processing a 5-series aluminum alloy to obtain an alloy sample; S2, carrying out solution treatment on the alloy sample obtained in the step S1, and quenching at room temperature; S3, performing cyclic plastic treatment on the alloy sample subjected to S2 quenching to obtain the reinforced 5-series aluminum alloy.
3. 3. The method for strengthening a 5-series aluminum alloy according to claim 2, wherein in the step S1, the alloy sample comprises two clamping sections and a gauge length section which are coaxially arranged, the gauge length section is fixedly connected between the two clamping sections, the diameter of the gauge length section is 6.0+/-0.1 mm, the length of the gauge length section is 15+/-0.1 mm, the diameter of each clamping section is 12.0+/-0.1 mm, the length of each clamping section is 40+/-0.5 mm, the gauge length section and the two clamping sections are transited through an arc surface, and the radius of the arc surface is 30.0+/-0.5 mm.
4. 4. The method for strengthening a 5-series aluminum alloy according to claim 2, wherein in the step S2, a layer of carbon powder with a thickness of 8-10 mm is coated on the surface of the alloy Jin Shiyang before the solution treatment.
5. 5. The method for strengthening a 5-series aluminum alloy according to claim 2, wherein in the step S2, the solid solution temperature is 440-460 ℃ and the heat is preserved for 3 hours.
6. 6. The method for strengthening a 5-series aluminum alloy according to claim 2, wherein in the step S2, the quenching mode is water quenching, and the quenching transfer time is less than 30S.
7. 7. The method for strengthening a 5-series aluminum alloy according to claim 2, wherein in the step S3, the cyclic plastic treatment is performed by placing the alloy sample quenched in the step S2 into a fatigue test system, and applying a horizontal stress to the alloy Jin Shiyang under a sine waveform to perform cyclic symmetrical stretching-compression treatment for a plurality of times.
8. 8. The method for strengthening a 5-series aluminum alloy according to claim 7, wherein the frequency of the sinusoidal waveform is 0.15-0.2 Hz.
9. 9. The method for strengthening a 5-series aluminum alloy according to claim 7, wherein the horizontal stress applied to the alloy Jin Shiyang is as follows: Wherein σ 0 and σ max represent the yield strength and tensile strength of the quenched alloy, respectively, and N total and N i represent the total number of cycles during the stretch-compression process and the number of ith cycles, respectively.
10. 10. The method for strengthening a 5-series aluminum alloy according to claim 7, wherein the number of cycles is 500 to 800 weeks.

Description

5-Series aluminum alloy and strengthening method thereof Technical Field The invention relates to the technical field of aluminum alloy, in particular to a 5-series aluminum alloy and a strengthening method thereof. Background In the fields of rail transit, ship manufacturing, ocean engineering, etc., 5-series aluminum alloys have been widely used by virtue of their excellent specific strength, good corrosion resistance, and excellent workability. The strengthening of such alloys relies mainly on solid solution strengthening mechanisms, i.e. solid solution of Mg atoms in the aluminium matrix. However, the strengthening approach causes obvious performance balance difficulty that when the Mg content is higher than 3.5 wt percent, although the 5-series aluminum alloy can obtain higher strength, continuous netlike beta phase (Al 3Mg2) is extremely easy to form at the grain boundary in the long-term service process at the medium temperature (50-200 ℃) so as to lead solute near the grain boundary to be depleted, further serious intergranular corrosion and stress corrosion cracking sensitivity are induced, and serious threat is caused to service safety under complex working conditions, and conversely, if the Mg content is reduced to be lower than 3.5 wt percent, sensitization behaviors can be effectively inhibited and excellent intergranular corrosion resistance can be obtained, but the solid solution strengthening effect can be obviously weakened, so that the material strength is insufficient, and the requirement of a lightweight structural member on high strength is difficult to meet. To address the challenges described above, existing research has been largely developed along two technological paths. One is a microalloying route (e.g., adding Zn, cu, sc, zr, etc.) intended to provide additional strengthening by forming a precipitated or dispersed phase and to suppress grain boundary precipitation. However, the method generally introduces complex alloy component design, obviously increases material cost, and the multi-element alloying can cause obstruction to recycling of the alloy, which is unfavorable for the economy and environmental protection of the whole life cycle. Secondly, severe plastic deformation technology such as equal channel angular extrusion, accumulation and rolling and the like tries to improve the strength through grain refinement and the introduction of high-density dislocation. However, the method often causes the plasticity to be greatly reduced, and the thinned crystal boundary and high-density dislocation possibly become new positions for corrosion initiation, so that the synchronous improvement of the strength and the corrosion resistance is difficult to realize. More importantly, the two strategies can not fundamentally solve the problem of segregation of Mg atoms along grain boundaries, and can not prevent rapid formation of continuous network beta phase in the subsequent sensitization process, so that the mutual exclusion bottleneck between corrosion resistance and mechanical properties of the 5-series aluminum alloy can not be broken through all the time. In summary, how to further improve the strength of the 5-series aluminum alloy and realize the cooperative optimization of the mechanical property and the corrosion resistance on the premise of keeping the excellent corrosion resistance of the aluminum alloy has become a key technical problem to be solved in the current urgent need. Disclosure of Invention Aiming at the defects existing in the prior art, the invention aims to provide a 5-series aluminum alloy and a strengthening method thereof, so as to solve the problem that the 5-series aluminum alloy in the prior art cannot well consider mechanical properties and corrosion resistance. In order to achieve the above purpose, the present invention adopts the following technical scheme: The 5-series aluminum alloy comprises, by mass, 2.4-8.6% of Mg, and the balance of Al and unavoidable impurities. The invention also provides a method for strengthening the 5-series aluminum alloy, which comprises the following steps: s1, processing a 5-series aluminum alloy to obtain an alloy sample; S2, carrying out solution treatment on the alloy sample obtained in the step S1, and quenching at room temperature; S3, performing cyclic plastic treatment on the alloy sample subjected to S2 quenching to obtain the reinforced 5-series aluminum alloy. Preferably, in step S1, the alloy sample includes two clamping sections and a gauge length section coaxially arranged, the gauge length section is fixedly connected between the two clamping sections, the diameter of the gauge length section is 6.0±0.1mm, the length of the gauge length section is 15±0.1mm, the diameter of each clamping section is 12.0±0.1mm, the length of each clamping section is 40±0.5mm, the gauge length section and the two clamping sections are transited through an arc surface, and the radius of the arc surface is 30.0±0.5 mm. Preferably