阅读说明：本技术 一种高强韧耐蚀Al-Zn-Mg-Cu合金制备方法 (Preparation method of high-strength and high-toughness corrosion-resistant Al-Zn-Mg-Cu alloy ) 是由 曾元松 张新明 徐严谨 韩宝帅 朱玉涛 何克准 郑许 于 2021-01-19 设计创作，主要内容包括：本发明公开了一种高强韧耐蚀Al-Zn-Mg-Cu合金制备方法,包括以下操作步骤：(1)设计合金的成分；(2)进行Al熔炼,待熔化完全后扒渣,并添加Zn、Mg、Cu,辅助电磁搅拌技术,取样检测成分合格后转到保温炉充入高纯混合气体精炼,扒渣后取样成分检测合格在高纯混合气体下进行二次精炼,得到铸造锭坯；(3)将铸造锭坯经均匀化处理,铸锭经热挤压成形板坯；板坯经8-12道次轧制特定厚度的板材；(4)对板材进行固溶处理,然后采用喷淋淬火处理,再对板材进行预拉伸处理消除残余应力,再进行时效处理,得到高强韧耐蚀Al-Zn-Mg-Cu合金。本发明提供的一种高强韧耐蚀Al-Zn-Mg-Cu合金制备方法,实现了力学性能与耐蚀性能的匹配,提高了铝合金的应用范围。(The invention discloses a preparation method of a high-strength and high-toughness corrosion-resistant Al-Zn-Mg-Cu alloy, which comprises the following operation steps: (1) designing the composition of the alloy; (2) carrying out Al smelting, slagging off after the Al is completely melted, adding Zn, Mg and Cu, assisting an electromagnetic stirring technology, transferring to a heat preservation furnace to be filled with high-purity mixed gas for refining after sampling and detecting components are qualified, and carrying out secondary refining under the high-purity mixed gas after slagging off and sampling and detecting components are qualified to obtain a cast ingot blank; (3) homogenizing the cast ingot blank, and performing hot extrusion on the cast ingot to form a plate blank; rolling the plate blank into a plate with a specific thickness by 8-12 passes; (4) the plate is subjected to solid solution treatment, then spray quenching treatment is adopted, pre-stretching treatment is carried out on the plate to eliminate residual stress, and then aging treatment is carried out to obtain the high-strength high-toughness corrosion-resistant Al-Zn-Mg-Cu alloy. The preparation method of the high-strength-toughness corrosion-resistant Al-Zn-Mg-Cu alloy provided by the invention realizes the matching of mechanical property and corrosion resistance, and improves the application range of the aluminum alloy.)

1. A preparation method of a high-strength and high-toughness corrosion-resistant Al-Zn-Mg-Cu alloy is characterized by comprising the following operation steps:

(1) designing the components of the alloy: comprises 5.5-6.1 wt.% Zn, 2.5-3.2 wt.% Mg, 1.5-2.0 wt.% Cu, 0.03-0.05 wt.% Cr, 0.03-0.05 wt.% Mn, Si content less than 0.005 wt.%, Fe content less than 0.05 wt.%, and the balance of Al;

(2) setting the smelting temperature in the furnace at 760 ℃ of 720-;

(3) homogenizing the cast ingot blank, and performing hot extrusion on the cast ingot to form a plate blank, wherein the thickness of the plate blank is 420-450 mm; rolling the plate blank into a plate with a specific thickness by 8-12 passes, wherein the single rolling reduction is more than 20mm, and the final rolling thickness of the plate is 25-100 mm;

(4) the plate is subjected to solid solution treatment, then spray quenching treatment is adopted, pre-stretching treatment is carried out on the plate to eliminate residual stress, and then aging treatment is carried out to obtain the high-strength high-toughness corrosion-resistant Al-Zn-Mg-Cu alloy.

2. The method for preparing the high-toughness corrosion-resistant Al-Zn-Mg-Cu alloy according to claim 1, wherein in the step (1), Al is any one of a high-purity aluminum ingot with the purity of 99.8%, Al-50Cu and Al-Zr5, the Cu is electrolytic copper, the mass fraction of Zn is 99.5%, and the mass fraction of magnesium is 99.92%.

3. The method for preparing the high-toughness corrosion-resistant Al-Zn-Mg-Cu alloy according to claim 1, wherein in the step (2), the refining agent is Al-Ti 5% -B0.2% wire.

4. The method for preparing the Al-Zn-Mg-Cu alloy with high toughness and corrosion resistance as claimed in claim 1, wherein in the step (3), the homogenization treatment process comprises the steps of heat preservation at 440 ℃ for 10-14h at 420-.

5. The preparation method of the high-toughness corrosion-resistant Al-Zn-Mg-Cu alloy according to claim 1, wherein in the step (4), the specific process of solution treatment comprises the following steps: keeping the temperature at 450-460 ℃ for 2-3h, and keeping the temperature at 470-480 ℃ for 1-2 h.

6. The preparation method of the high-strength-toughness corrosion-resistant Al-Zn-Mg-Cu alloy as claimed in claim 1, wherein in the step (4), the quenching transfer time is not more than 5s and the cooling speed is not less than 10 ℃/s during the spray quenching treatment.

7. The preparation method of the high-toughness corrosion-resistant Al-Zn-Mg-Cu alloy as claimed in claim 1, wherein in the step (4), the aging treatment is carried out by keeping the temperature at 120 ℃ for 6-8h and keeping the temperature at 150 ℃ and 170 ℃ for 20-35 h.

Technical Field

The invention relates to the technical field of alloy preparation, in particular to a preparation method of a high-strength and high-toughness corrosion-resistant Al-Zn-Mg-Cu alloy.

Background

With the development of aviation design and manufacturing technology and the diversification of airplane service environments, the requirement of airplane design on the performance of aluminum alloy is developed from the initial requirement of static strength to the current requirement of high strength and high toughness of aluminum alloy, as well as high damage tolerance characteristics such as good corrosion resistance, fatigue resistance, high fracture toughness and the like.

In the existing Al-Zn-Mg-Cu alloy, although some alloy strength and fatigue property meet the requirements, the fracture toughness does not meet the requirements. The yield strength of the currently common aluminum alloy, such as 7075 alloy, is 435MPa, and the fracture toughness of the T7351 alloy in a tempering state is close to 24-27 MPa.m^1/2The yield strength of 7050-T73651 is 455MPa, the fracture toughness is obviously improved, and 29-35 MPa.m^1/2。

In addition, Al-Zn-Cu-Mg serving as a high-strength aluminum alloy has the characteristic of poor salt spray corrosion resistance inevitably. The aluminum alloy is easy to chemically react with oxygen due to the active chemical property, for example, in the environment with high halide content such as industrial polluted humid environment and marine environment, the halide can destroy the compact oxide film on the surface of the aluminum alloy, so that the internal metal is exposed in the corrosive medium, and the corrosive medium can continuously and deeply corrode along the grain boundary or in the grain of the alloy, so that the mechanical property and the fatigue resistance of the aluminum alloy are rapidly reduced. This presents a significant challenge to the corrosion resistance of the major structural components of the aircraft. Therefore, at present, there is an urgent need to design an aluminum alloy plate which has superior strength, toughness, fatigue and stress corrosion resistance, and can meet the requirements of future airplanes.

Disclosure of Invention

In recent years, the new requirement of the aluminum alloy for aerospace is that the aluminum alloy has good marine salt spray corrosion resistance on the premise of maintaining the strength and the toughness. In the process of aluminum alloy development, certain contradiction between strength and corrosion resistance is often shown, so that how to synergistically improve the strength and corrosion resistance of the alloy is a critical problem to be solved in the research of high-strength aluminum alloy and is the difficult point of high-performance corrosion-resistant aluminum alloy development. At present, a few researches on high-strength ocean salt spray corrosion resistant aluminum alloy are carried out, and the researches mainly stay in component fine adjustment and improvement of a traditional heat treatment system of traditional alloy, and no specially developed corrosion resistant aluminum alloy exists. Based on the Al-Zn-Cu-Mg alloy, the Al-Zn-Cu-Mg alloy composition is designed, and the preparation and processing technology is developed to comprehensively optimize the mechanical property and the corrosion resistance of the aluminum alloy and meet the requirement of the development of the aviation industry on the corrosion-resistant aluminum alloy.

The invention is realized by the following technical scheme.

A preparation method of high-strength and high-toughness corrosion-resistant Al-Zn-Mg-Cu alloy comprises the following operation steps:

(1) designing the components of the alloy: comprises 5.5-6.1 wt.% Zn, 2.5-3.2 wt.% Mg, 1.5-2.0 wt.% Cu, 0.03-0.05 wt.% Cr, 0.03-0.05 wt.% Mn, Si content less than 0.005 wt.%, Fe content less than 0.05 wt.%, and the balance of Al;

(2) setting the smelting temperature in the furnace at 760 ℃ of 720-;

(3) homogenizing the cast ingot blank, and performing hot extrusion on the cast ingot to form a plate blank, wherein the thickness of the plate blank is 420-450 mm; rolling the plate blank into a plate with a specific thickness by 8-12 passes, wherein the single rolling reduction is more than 20mm, and the final rolling thickness of the plate is 25-100 mm;

(4) the plate is subjected to solid solution treatment, then spray quenching treatment is adopted, pre-stretching treatment is carried out on the plate to eliminate residual stress, and then aging treatment is carried out to obtain the high-strength high-toughness corrosion-resistant Al-Zn-Mg-Cu alloy.

Specifically, in the step (1), Al is any one of a high-purity aluminum ingot with a purity of 99.8%, Al-50Cu, and Al-Zr5, the Cu is electrolytic copper, the mass fraction of Zn is 99.5%, and the mass fraction of magnesium is 99.92%.

Specifically, in the step (2), the refining agent is Al-Ti 5% -B0.2% silk.

Specifically, in the step (3), the homogenization treatment process comprises the steps of heat preservation at 440 ℃ for 10-14h under 420-.

Specifically, in the step (4), the specific process of the solution treatment is as follows: keeping the temperature at 450-460 ℃ for 2-3h, and keeping the temperature at 470-480 ℃ for 1-2 h.

Specifically, in the step (4), during the spray quenching treatment, the quenching transfer time is less than or equal to 5s, and the cooling speed is more than or equal to 10 ℃/s.

Specifically, in the step (4), the aging treatment is carried out by heat preservation at 120 ℃ for 6-8h and at 150 ℃ and 170 ℃ for 20-35 h.

According to the technical scheme, the beneficial effects of the invention are as follows:

according to the preparation method of the high-strength-toughness corrosion-resistant Al-Zn-Mg-Cu alloy, the mechanical property and the corrosion resistance are matched through the reasonable alloy formula and the preparation process provided by the application, and the application range of the aluminum alloy is widened. The corrosion resistance of the Al-Zn-Mg-Cu alloy is effectively improved by reducing the contents of Mn, Cr, Ti, Si and Fe in the Al-Zn-Mg-Cu alloy, and meanwhile, the Al-Zn-Mg-Cu alloy can be ensured to have certain mechanical properties. According to the preparation method, the impurity content in the Al-Zn-Mg-Cu alloy is effectively reduced by adopting a certain smelting temperature, refining temperature and casting temperature and carrying out homogenization treatment, spray quenching treatment and aging treatment.

Detailed Description

Embodiments of the present invention will be described in detail below with reference to examples, but it will be understood by those skilled in the art that the following examples are only illustrative of the present invention and should not be construed as limiting the scope of the present invention. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer.

Example 1

A preparation method of high-strength and high-toughness corrosion-resistant Al-Zn-Mg-Cu alloy comprises the following operation steps:

(1) designing the components of the alloy: the aluminum alloy comprises 5.5 wt.% of Zn, 2.5 wt.% of Mg, 1.5-2.0 wt.% of Cu, 0.03-wt.% of Cr, 0.03 wt.% of Mn and Si, the content of Fe is less than 0.005 wt.%, and the balance of Al, wherein Al is a high-purity aluminum ingot with the purity of 99.8%, Cu is electrolytic copper, the mass fraction of Zn is 99.5%, and the mass fraction of magnesium is 99.92%;

(2) setting the smelting temperature in a furnace at 720 ℃, carrying out Al smelting, slagging off after complete melting, adding Zn, Mg and Cu, assisting an electromagnetic stirring technology, transferring a heat preservation furnace to a refining furnace to be filled with high-purity mixed gas for refining after sampling and detecting components are qualified, wherein the refining temperature is 720 ℃, carrying out secondary refining under the high-purity mixed gas after slagging-off and sampling and component detection are qualified, adding 0.2% of refining agent Al-Ti 5% -B, filtering and deslagging, then casting to obtain a cast ingot blank, wherein the casting temperature is set to 730 ℃, the casting speed is 40mm/min, and the diameter of the formed ingot is 460 mm;

(3) homogenizing the cast ingot blank, and performing hot extrusion on the cast ingot to form a plate blank, wherein the thickness of the plate blank is 420 mm; rolling a plate blank into a plate with a specific thickness by 10 passes, wherein the single rolling reduction is more than 20mm, the final rolling thickness of the plate is 25-100mm, and the homogenization treatment process comprises the steps of preserving heat at 420 ℃ for 14h and preserving heat at 460 ℃ for 24 h;

(4) carrying out solid solution treatment on the plate, then carrying out spray quenching treatment, wherein the quenching transfer time is less than or equal to 5s, the cooling speed is more than or equal to 10 ℃/s, then carrying out pre-stretching treatment on the plate to eliminate residual stress, and then carrying out aging treatment to obtain the high-strength and high-toughness corrosion-resistant Al-Zn-Mg-Cu alloy, wherein the specific process of the solid solution treatment is as follows: keeping the temperature at 450 ℃ for 3h, keeping the temperature at 480 ℃ for 1h, and keeping the temperature at 120 ℃ for 8h and keeping the temperature at 160 ℃ for 24 h.

Example 2

A preparation method of high-strength and high-toughness corrosion-resistant Al-Zn-Mg-Cu alloy comprises the following operation steps:

(1) designing the components of the alloy: the alloy comprises 5.8 wt.% of Zn, 3.0 wt.% of Mg, 1.7 wt.% of Cu, 0.04 wt.% of Cr, 0.04 wt.% of Mn and Si, the content of Fe is less than 0.005 wt.%, and the balance of Al, wherein Al is Al-50Cu in purity, Cu is electrolytic copper, the mass fraction of Zn is 99.5%, and the mass fraction of magnesium is 99.92%. (ii) a

(2) Setting the smelting temperature in a furnace at 740 ℃, carrying out Al smelting, slagging off after complete smelting, adding Zn, Mg and Cu, assisting an electromagnetic stirring technology, transferring a heat preservation furnace to a refining furnace to be filled with high-purity mixed gas for refining after sampling and detecting components are qualified, wherein the refining temperature is 735 ℃, carrying out secondary refining under the high-purity mixed gas after slagging-off and sampling and component detection are qualified, adding 0.2% of wire of refining agent Al-Ti 5% -B, filtering and deslagging, then casting to obtain a cast ingot blank, wherein the casting temperature is set at 745 ℃, the casting speed is 60mm/min, and the diameter of the formed ingot is 460 mm;

(3) homogenizing the cast ingot blank, and performing hot extrusion on the cast ingot to form a plate blank, wherein the thickness of the plate blank is 420 mm; rolling a plate with a specific thickness by using a plate blank through 8 passes, wherein the single rolling reduction is more than 20mm, the final rolling thickness of the plate is 25mm, and the homogenization treatment process comprises the steps of preserving heat at 420 ℃ for 10 hours and preserving heat at 460 ℃ for 18 hours;

(4) carrying out solid solution treatment on the plate, then carrying out spray quenching treatment, wherein the quenching transfer time is less than or equal to 5s, the cooling speed is more than or equal to 10 ℃/s, then carrying out pre-stretching treatment on the plate to eliminate residual stress, and then carrying out aging treatment to obtain the high-strength and high-toughness corrosion-resistant Al-Zn-Mg-Cu alloy, wherein the specific process of the solid solution treatment is as follows: keeping the temperature at 450 ℃ for 3h, keeping the temperature at 480 ℃ for 2h, and keeping the temperature at 120 ℃ for 6h and keeping the temperature at 150 ℃ for 20 h.

Example 3

A preparation method of high-strength and high-toughness corrosion-resistant Al-Zn-Mg-Cu alloy comprises the following operation steps:

(1) designing the components of the alloy: the aluminum alloy comprises 6.1 wt.% of Zn, 3.2 wt.% of Mg, 2.0 wt.% of Cu, 0.05 wt.% of Cr, 0.05 wt.% of Mn and Si, the content of Fe is less than 0.005 wt.%, and the balance of Al, wherein Al is a high-purity aluminum ingot with the purity of 99.8%, Cu is electrolytic copper, the mass fraction of Zn is 99.5%, and the mass fraction of magnesium is 99.92%. (ii) a

(2) Setting the smelting temperature in a furnace at 760 ℃, carrying out Al smelting, slagging off after complete melting, adding Zn, Mg and Cu, assisting an electromagnetic stirring technology, transferring to a heat preservation furnace to be filled with high-purity mixed gas for refining after sampling and detecting components are qualified, wherein the refining temperature is 740 ℃, carrying out secondary refining under the high-purity mixed gas after slagging-off and sampling and component detection are qualified, adding 0.2% of refining agent Al-Ti 5% -B, filtering and deslagging, then casting to obtain a cast ingot blank, wherein the casting temperature is set to 750 ℃, the casting speed is 80mm/min, and the diameter of the formed ingot is 460 mm;

(3) homogenizing the cast ingot blank, and performing hot extrusion on the cast ingot to form a plate blank, wherein the thickness of the plate blank is 450 mm; rolling a plate blank into a plate with a specific thickness by 12 passes, wherein the single rolling reduction is more than 20mm, the final rolling thickness of the plate is 50mm, and the homogenization treatment process comprises the steps of keeping the temperature at 440 ℃ for 10 hours and keeping the temperature at 475 ℃ for 18 hours;

(4) carrying out solid solution treatment on the plate, then carrying out spray quenching treatment, wherein the quenching transfer time is less than or equal to 5s, the cooling speed is more than or equal to 10 ℃/s, then carrying out pre-stretching treatment on the plate to eliminate residual stress, and then carrying out aging treatment to obtain the high-strength and high-toughness corrosion-resistant Al-Zn-Mg-Cu alloy, wherein the specific process of the solid solution treatment is as follows: keeping the temperature at 460 ℃ for 2.5h, keeping the temperature at 477 ℃ for 1.5h, and keeping the temperature at 120 ℃ for 6h and keeping the temperature at 155 ℃ for 30 h.

The performance test of the high strength and toughness corrosion-resistant Al-Zn-Mg-Cu alloy prepared in each example is carried out, and the test results are shown in Table 1:

TABLE 1 test results of high toughness corrosion resistant Al-Zn-Mg-Cu alloy

The components of the high-strength, high-toughness and corrosion-resistant Al-Zn-Mg-Cu alloy prepared in the embodiment 1 at different thicknesses are shown in Table 2, the components of the high-strength, high-toughness and corrosion-resistant Al-Zn-Mg-Cu alloy meet the set range, and the difference of different thickness positions is small; the impurity content is shown in table 3, both the hydrogen content and the slag content are less than the industry level.

TABLE 2 high toughness corrosion resistant Al-Zn-Mg-Cu alloy compositions (wt.%)

Alloy (I)	Zn	Mg	Cu	Mn	Cr	Ti	Si	Fe
									7075	5.1-6.1	2.1-2.9	1.2-2.0	0.3	/	0.2	0.4	0.5
7050	5.7-6.7	1.9-2.6	2.0-2.6	0.1	0.08-0.15	0.06	0.12	0.15
									Surface of sheet material	5.957	2.646	1.573	0.030	0.041	0.041	<0.005	0.017
Sheet material 1/4 thickness	5.721	2.638	1.516	0.032	0.047	0.047	<0.005	0.026
									Sheet material 1/2 thickness	5.836	2.515	1.436	0.031	0.047	0.047	<0.005	0.021

TABLE 3 high toughness corrosion resistant Al-Zn-Mg-Cu alloy impurity content

The embodiments described above are some, but not all embodiments of the invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the invention as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.