CN-117488151-B - High-strength large-plasticity corrosion-resistant Al-Zn-Mn-Cu-Mg aluminum alloy and application thereof

Abstract

The invention provides a high-strength large-plasticity corrosion-resistant Al-Zn-Mn-Cu-Mg aluminum alloy and application thereof, belongs to the technical field of aluminum alloys, uses Mn element as an important alloy element, improves corrosion resistance through Mn (Mn) element to enable the alloy to have excellent corrosion resistance, reduces the content of Mg and Cu elements, regulates and controls the precipitation amount and distribution of eta phase and theta phase, and the prepared alloy has tensile strength of more than 550MPa and elongation of not less than 20 percent, belongs to ultrahigh-strength aluminum alloy with high plastic deformation capacity, is suitable for section bar processing in the fields of transportation, aviation, aerospace and the like, and has good practicability.

Inventors

• WU JILI
• Long Ruiyang
• SHANG YU
• XIAO SHENGYANG
• ZHOU WENYAN

Assignees

• 江苏大学

Dates

Publication Date

20260512

Application Date

20231103

Claims (5)

1. 1. A method for preparing an Al-Zn-Mn-Cu-Mg aluminum alloy sheet, comprising: (1) The raw materials of the Al-Zn-Mn-Cu-Mg aluminum alloy are calculated and weighed according to the components of the Al-Zn-Mn-Cu-Mg aluminum alloy with high strength and high plasticity, wherein the components of the Al-Zn-Mn-Cu-Mg aluminum alloy comprise 6.5 to 9.5 wt percent of Zn, 0.6 to 1.3 wt percent of Mn, 0.4 to 1. wt to 1.2 wt percent of Cu, 0.4 to 1.2 wt percent of Mg, the total content of other impurities is not more than 0.15 wt percent, the content of single impurity components is not more than 0.02 wt percent, and the balance of Al. (2) Smelting the raw materials weighed in the step (1) into an Al-Zn-Mn-Cu-Mg alloy melt, adding the Al-Zn-Mn-Cu-Mg alloy melt into a preheated casting mold, and naturally cooling to obtain an alloy cast ingot; (3) Preheating and preserving heat of the alloy cast ingot, forging and pressing to manufacture a thick plate after the heat preservation is finished, and obtaining the thick plate after the forging and pressing are finished; The forging conditions are that the pressing speed is 5 mm/s-15 mm/s, the alloy ingot is continuously forged to 2/3-1/3 of the size of the alloy ingot in the step (2), and the temperature is not controlled in the forging process; (4) Carrying out heat preservation treatment on the thick plate with the surface stains removed again, and obtaining a prepared thick plate after the treatment is finished; the heat preservation treatment is to preserve heat for 30-60 min at 420-460 ℃; (5) Carrying out multi-pass rolling on the prepared thick plate by using double-roller rolling, carrying out heat preservation treatment after each pass of rolling, and carrying out rolling again after the heat preservation treatment is finished until the thickness is designed; The multi-pass rolling comprises the steps that the first pass pressing amount is 15% -30% of the size of the prepared thick plate, the subsequent pressing amount of each pass is 10% -20% of the thickness of the previous pass, and the plate of the Al-Zn-Mn-Cu-Mg aluminum alloy with the target thickness is obtained through rolling; Carrying out heat preservation treatment for 45-60 min at the temperature which is 5-10 ℃ higher than the heat preservation temperature in the step (4) after each rolling; (6) And (3) obtaining the high-strength high-plasticity corrosion-resistant Al-Zn-Mn-Cu-Mg aluminum alloy plate after rolling.
2. 2. The method for producing an Al-Zn-Mn-Cu-Mg aluminum alloy sheet according to claim 1, wherein in the step (1), the Al-Zn-Mn-Cu-Mg aluminum alloy has a Mn/Zn mass ratio of 0.09 to 0.16, a Mn/Cu and Mn/Mg mass ratio of 1.00 or more, and a Cu/Mg mass ratio of 0.50 to 1.29.
3. 3. The method of producing Al-Zn-Mn-Cu-Mg aluminum alloy sheet according to claim 1, wherein in step (1), the raw material includes industrial pure aluminum, industrial pure zinc, industrial pure manganese or Al-Mn master alloy, industrial pure copper or Al-Cu master alloy, industrial pure magnesium or Al-Mg master alloy.
4. 4. The method for producing an Al-Zn-Mn-Cu-Mg aluminum alloy sheet according to claim 1, wherein in the step (2), the mold is preheated to 350 to 410 ℃.
5. 5. The method for preparing an Al-Zn-Mn-Cu-Mg aluminum alloy sheet according to claim 1, wherein in the step (3), the preheating and heat-preserving conditions are that heat is preserved for 45-70 min at 430-480 ℃.

Description

High-strength large-plasticity corrosion-resistant Al-Zn-Mn-Cu-Mg aluminum alloy and application thereof Technical Field The invention belongs to the technical field of aluminum alloy, and particularly relates to a high-strength high-plasticity corrosion-resistant Al-Zn-Mn-Cu-Mg aluminum alloy and application thereof. Background As a structural metal material, the aluminum alloy has the characteristics of rich resources, environmental friendliness, convenient recovery and the like, and is dominant in the fields of transportation, ocean engineering, ship engineering and constructional engineering. The rapid development of the transportation and aerospace industries rapidly increases the demand of aluminum alloy, and simultaneously, higher requirements are also put on the performance of the aluminum alloy, and particularly, the development of ultra-high strength aluminum alloy represented by Al-Cu system and Al-Zn system plays an important role in promoting the light weight of tools and reducing energy consumption. Al-Zn based alloys have been widely used for many years, common alloy systems including Al-Zn-Mg and Al-Zn-Mg-Cu. The addition of Mg or Cu increases the strength of the alloy, but the main strengthening phase in such alloys is the eta phase (the precipitated phase consisting of Mg and Zn elements, typically of the stoichiometric formula MgZn 2). With the development of aluminum alloy technology, the content of Mg and Cu elements is improved, and the original alloy is subjected to component optimization by Zr, sc or other rare earth elements, so that the method becomes a main means for further improving the strength of Al-Zn alloy. However, as the degree of alloying increases, the eta phase and theta phase (the precipitated phase consisting of Al and Cu elements, typically of the formula Al 2 Cu) are added to the aluminum alloy, and a large chemical potential difference exists between these phases and the alloy matrix (alpha-Al), resulting in a decrease in the corrosion resistance of the alloy, and in particular, a strong increase in the tendency of stress corrosion cracking. In addition, the continuous distribution of the strengthening phase at the grain boundaries of the matrix also weakens the plastic formability of the alloy, and is prone to cracking during the manufacture of sheets or foils, resulting in increased scrap rates. At present, a conventional method for overcoming eta-phase and theta-phase distribution characteristics of the Al-Zn alloy is multistage aging treatment or thermomechanical treatment, so that the heat treatment process of the alloy is complicated. From the standpoint of total strength design, the use of elemental substitution (i.e., alloying means) on the original alloy system is a common design method, but it is difficult to break through the limitations of the original composition range. The selection of components in an alloy system with more than 4 components is a complex process of multiple variables, and the precipitation process of a strengthening phase is also considered, so that the design of a novel Al-Zn alloy is slow, and the corrosion resistance problem of the alloy is difficult to overcome. Therefore, a new aluminum alloy with high strength, large plasticity and corrosion resistance is designed in an alloy system with more than 4 components, and has important engineering application value. Disclosure of Invention Aiming at the defects in the prior art, the invention provides the high-strength high-plasticity corrosion-resistant Al-Zn-Mn-Cu-Mg aluminum alloy and the application thereof, wherein the Al-Zn-Mn-Cu-Mg aluminum alloy uses Mn element as an important alloy element, improves corrosion resistance through Mn (Mn) element, enables the alloy to have excellent corrosion resistance, reduces the content of Mg and Cu elements, regulates and controls the precipitation amount and distribution of eta phase and theta phase, prepares the ultrahigh-strength aluminum alloy with tensile strength of more than 550MPa and elongation of not less than 20 percent, belongs to the field of profile processing with high plastic deformation capacity, and has good practicability. In order to achieve the technical purpose, the invention adopts the following technical means. The invention firstly provides a high-strength large-plasticity corrosion-resistant Al-Zn-Mn-Cu-Mg aluminum alloy, which comprises 6.5 to 9.5 weight percent of Zn, 0.6 to 1.3 weight percent of Mn, 0.4 to 1.2 weight percent of Cu, 0.4 to 1.2 weight percent of Mg, the total content of other impurities is not more than 0.15 weight percent, the content of single impurity components is not more than 0.02 weight percent, and the balance of Al. Preferably, in the Al-Zn-Mn-Cu-Mg aluminum alloy, the mass ratio of Mn/Zn is 0.09-0.16, the mass ratio of Mn/Cu and Mn/Mg is more than or equal to 1.00, and the mass ratio of Cu/Mg is 0.50-1.29. The invention also provides application of the Al-Zn-Mn-Cu-Mg aluminum alloy in pr