High-strength high-corrosion-resistant aluminum-magnesium alloy and method for preparing same

Abstract

The application provides high-strength high-corrosion-resistance aluminum-magnesium alloy and a preparation method thereof, and the aluminum-magnesium alloy contains Mg: 8.3-9.6%, Mn: 0.4-0.8%, Ti: 0.05-0.15%, Zr: 0.05-0.2%, Ce: 0.1-0.5% by mass, and the balance is Al and inevitable impurities, and the aluminum-magnesium alloy contains Al 13 CeMg6 phase. The high-strength high-corrosion-resistance aluminum-magnesium alloy with the composition has excellent mechanical properties and intergranular corrosion resistance.

Description

Technical Field

[0001] This invention belongs to the field of alloy materials technology, specifically relating to a high-strength, high-corrosion-resistant Ce-containing aluminum-magnesium alloy and its preparation method. Background Technology

[0002] Aluminum-magnesium alloys, due to their low density, excellent corrosion resistance, good machinability and weldability, and high specific strength, are widely used in structural components in fields such as building construction, automobile manufacturing, aerospace, shipbuilding, 3C electronics, and medical devices. They are also applied in emerging fields where lightweighting is being promoted, such as photovoltaic brackets and wind turbine components. Their use as structural materials is particularly prominent in corrosive marine environments.

[0003] With the demands of industrial development, traditional aluminum-magnesium alloys, with their relatively low strength, are unable to meet industrial requirements. The main strengthening mechanisms of aluminum-magnesium alloys are solid solution strengthening, deformation strengthening, grain refinement strengthening, and second-phase strengthening. While the addition of magnesium significantly enhances the overall strengthening effect of the alloy, it severely reduces corrosion resistance, limiting its applications. Therefore, the key to solving the problem of limited applications for such alloys lies in how to improve their corrosion resistance while maintaining the strength of high-Mg-content aluminum-magnesium alloys. Summary of the Invention

[0004] The present invention aims to solve the above-mentioned problems of the prior art, and its purpose is to provide a high-strength, high-corrosion-resistant aluminum-magnesium alloy and its preparation method.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] In a first aspect, a high-strength, highly corrosion-resistant aluminum-magnesium alloy is provided, wherein, by mass percentage, the aluminum-magnesium alloy contains Mg: 8.3~9.6%, Mn: 0.4~0.8%, Ti: 0.05~0.15%, Zr: 0.05~0.2%, Ce: 0.1~0.5%, with the balance being Al and unavoidable impurities, and the aluminum-magnesium alloy contains a second phase Al. 13 CeMg6 phase.

[0007] Furthermore, the aluminum-magnesium alloy also contains Al. 20 Mn2Ce phase.

[0008] Furthermore, the aluminum-magnesium alloy contains 0.15-0.4% Ce by mass percentage.

[0009] Furthermore, the aluminum-magnesium alloy is in the form of a sheet material.

[0010] Secondly, a method for preparing the high-strength, high-corrosion-resistant aluminum-magnesium alloy described in the first aspect is provided, comprising:

[0011] Al ingots, Al-20Mn master alloy, Al-10Zr master alloy and Al-5Ti-B master alloy are sequentially added into the melting furnace for the first stage of hot melting treatment. The melt temperature is 760~780℃ to obtain aluminum alloy melt.

[0012] The aluminum alloy melt is cooled to 710~730℃, pure Mg ingots are added to it, and the mixture is stirred to obtain an aluminum-magnesium alloy melt.

[0013] The aluminum-magnesium alloy melt is heated to 780~800℃, CeO2 powder is added to it, and the mixture is stirred to obtain a Ce-containing aluminum-magnesium alloy melt.

[0014] After refining the Ce-containing aluminum-magnesium alloy melt, the temperature is raised to 760~780℃ and left to stand.

[0015] After standing, the Ce-containing aluminum-magnesium alloy melt is cast to obtain a high-strength, high-corrosion-resistant aluminum-magnesium alloy.

[0016] Compared with the prior art, one or more of the above technical solutions can achieve at least one of the following beneficial effects:

[0017] This invention provides a high-Mg content aluminum-magnesium alloy, whose alloying elements include Mg, Mn, and Ce, with a Mg content as high as 8.3-9.6%. Although high-Mg content aluminum alloys have good mechanical properties, the high content of the β phase in high-Mg aluminum alloys significantly reduces the corrosion resistance of the aluminum alloy. The aluminum-magnesium alloy of this invention contains a second phase, Al. 13 The CeMg6 phase, this second phase, effectively hinders dislocation movement, improves the alloy's strength, and Al... 13 The formation of the CeMg6 phase can reduce the amount of β-Al3Mg2 phase distributed continuously on the grain boundaries, reduce the growth kinetics of the β phase, and improve the alloy's resistance to intergranular corrosion.

[0018] The provided aluminum-magnesium alloy also contains Al 20 The Mn2Ce phase can further improve heat resistance and pitting corrosion resistance.

[0019] The provided method for preparing aluminum-magnesium alloys is simple, easy to implement, and low in cost. It can produce aluminum-magnesium alloys with specific composition and structure, while maintaining the strength of high-Mg content aluminum-magnesium alloys and improving the corrosion resistance of high-Mg aluminum alloys.

[0020] The provided method for preparing aluminum-magnesium alloys can use low-cost cerium oxide to achieve the control function of rare earth element Ce, which can reduce production costs and solve the problem of CeO2 being difficult to achieve efficient alloying. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 The images show the TEM image and selected area electron diffraction pattern of the stabilized aluminum-magnesium alloy prepared in Example 2, where (a) is the TEM image and (b) is the selected area electron diffraction pattern.

[0023] Figure 2 for Figure 1 The EDS diagram of the selected area, where (a) is the elemental distribution map, including the morphology map and the elemental distribution of Al, Mg, Mn, Ti, Zr and Ce, and (b) is the energy dispersive spectroscopy (EDS) diagram.

[0024] Figure 3 The image shows a TEM image of the stabilized aluminum-magnesium alloy prepared in Example 2.

[0025] Figure 4 for Figure 3 The EDS diagram of the selected area, where (a) is the elemental distribution map, including the morphology map and the elemental distribution of Al, Mg, Mn, Ti, Zr and Ce, and (b) is the energy dispersive spectroscopy (EDS) diagram.

[0026] Figure 5 for Figure 3 TEM bright-field image and selected area electron diffraction pattern of the selected area, where (a) is the TEM image and (b) is the selected area electron diffraction pattern.

[0027] Figure 6 The images show SEM images of commercially available cerium dioxide and cerium dioxide obtained from the decomposition of cerium carbonate, where (a) corresponds to commercially available cerium dioxide and (b) corresponds to cerium dioxide obtained from the decomposition of cerium carbonate.

[0028] Figure 7 The image shows the pitting morphology (SEM) of the aluminum-magnesium alloy prepared in the sensitized state in Comparative Example 1.

[0029] Figure 8 The image shows the pitting morphology (SEM) of the aluminum-magnesium alloy prepared in Example 1.

[0030] Figure 9 The images show cross-sectional views of intergranular corrosion of the stabilized alloys prepared in Comparative Example 1 and Examples 1-2, where (a) corresponds to Comparative Example 1, (b) corresponds to Example 1, and (c) corresponds to Example 2.

[0031] Figure 10The images show cross-sectional views of intergranular corrosion of the sensitized alloys prepared in Comparative Example 1 and Examples 1-2, where (a) corresponds to Comparative Example 1, (b) corresponds to Example 1, and (c) corresponds to Example 2. Detailed Implementation

[0032] Some embodiments provide a high-strength, high-corrosion-resistant aluminum-magnesium alloy, wherein, by mass percentage, the aluminum-magnesium alloy contains Mg: 8.3~9.6% (e.g., 8.3%, 8.5%, 8.8%, 9%, 9.2%, 9.4%, 9.6%, etc.), Mn: 0.4~0.8% (e.g., 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, etc.), and Ti: 0.05~0.15% (e.g., 0.05%, 0.08%, 0.1%). The aluminum-magnesium alloy contains Al, with the following proportions: 0.12%, 0.15%, etc.; Zr: 0.05~0.2% (e.g., 0.05%, 0.08%, 0.1%, 0.12%, 0.15%, 0.18%, 0.2%, etc.); Ce: 0.1~0.5% (e.g., 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, etc.), with the balance being Al and unavoidable impurities. 13 CeMg6 phase. This composition produces high-strength, high-corrosion-resistant aluminum-magnesium alloys with excellent mechanical properties due to its high magnesium content, and the second phase Al... 13 The CeMg6 phase significantly improves the intergranular corrosion resistance and mechanical properties of high-magnesium aluminum alloys. Al 13 The CeMg6 phase has submicron-sized particles, such as 550~650nm, for example, 550nm, 580nm, 600nm, 620nm, 650nm, etc.

[0033] In some preferred embodiments, the aluminum-magnesium alloy further comprises Al. 20 The Mn2Ce phase further improves the mechanical properties, pitting corrosion resistance, and heat resistance of aluminum-magnesium alloys. The Al... 20 The size of the Mn2Ce phase is in the micrometer or submicrometer range, for example, 4~8μm, such as 4μm, 5μm, 6μm, 7μm, 8μm, etc.

[0034] In some preferred embodiments, the aluminum-magnesium alloy contains Ce by mass percentage: 0.15~0.4%, for example 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, etc.

[0035] In some preferred embodiments, the aluminum-magnesium alloy is a sheet material.

[0036] Some embodiments provide a method for preparing high-strength, high-corrosion-resistant aluminum-magnesium alloys, including:

[0037] Al ingots, Al-20Mn master alloy, Al-10Zr master alloy, and Al-5Ti-B master alloy are sequentially added into a melting furnace for the first stage of hot melting treatment. The melt temperature is 760~780℃ (e.g., 760℃, 765℃, 770℃, 775℃, 780℃, etc.) to obtain aluminum alloy melt.

[0038] The aluminum alloy melt is cooled to 710~730℃ (e.g., 710℃, 715℃, 720℃, 725℃, 730℃, etc.), pure Mg ingots are added to it, and the mixture is stirred to obtain an aluminum-magnesium alloy melt.

[0039] The aluminum-magnesium alloy melt is heated to 780~800℃ (e.g., 780℃, 785℃, 790℃, 795℃, 800℃, etc.), CeO2 powder is added to it, and the mixture is stirred to obtain a Ce-containing aluminum-magnesium alloy melt.

[0040] After refining the Ce-containing aluminum-magnesium alloy melt, heat it to 760~780℃ (e.g., 760℃, 765℃, 770℃, 775℃, 780℃, etc.) and let it stand.

[0041] After standing, the Ce-containing aluminum-magnesium alloy melt is cast to obtain a high-strength, high-corrosion-resistant aluminum-magnesium alloy.

[0042] In some preferred embodiments, the CeO2 powder is a newly formed powder obtained by thermal decomposition of cerium carbonate; the thermal decomposition temperature is 300~550℃, for example 300℃, 350℃, 400℃, 450℃, 500℃, 550℃, etc.

[0043] In some preferred embodiments, the amount of CeO2 powder added is 0.1~0.5% of the total mass of Al ingot, Al-20Mn master alloy, Al-10Zr master alloy, Al-5Ti-B master alloy, Mg ingot, and CeO2 powder, for example, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, etc.

[0044] In some preferred embodiments, CeO2 is added by pressing CeO2 powder wrapped in aluminum foil into the melt through a bell jar.

[0045] In some preferred embodiments, the refining agent used in the refining process is hexachloroethane; the amount of hexachloroethane used is 0.2~0.4% of the total mass of Al ingots, Al-20Mn master alloy, Al-10Zr master alloy, Al-5Ti-B master alloy, Mg ingots, and CeO2 powder, for example, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, etc.; the refining time is 10~30 min, for example, 10 min, 12 min, 15 min, 18 min, 20 min, 22 min, 25 min, 28 min, 30 min, etc.

[0046] The refining process includes adding hexachloroethane to a Ce-containing aluminum-magnesium alloy melt for refining.

[0047] The settling time is 10-20 minutes, such as 10 minutes, 12 minutes, 15 minutes, 18 minutes, 20 minutes, etc.

[0048] In some preferred embodiments, the Ce-containing aluminum-magnesium alloy melt is first cooled to 700~720°C before being cast; the casting is metal mold casting.

[0049] In some preferred embodiments, the process further includes a step of processing the aluminum-magnesium alloy ingot; the processing includes: sequentially performing milling, homogenization, rolling deformation and annealing on the aluminum-magnesium alloy ingot.

[0050] In some preferred embodiments, the homogenization treatment temperature is 390~410℃, for example, 390℃, 400℃, 410℃, etc.; the homogenization treatment heat preservation time is 18~30h, for example, 18h, 20h, 22h, 24h, 26h, 28h, 30h, etc.; and water cooling is performed immediately after the homogenization treatment.

[0051] In some preferred embodiments, the annealing temperature is 230~280℃, for example 230℃, 240℃, 250℃, 260℃, 270℃, 280℃, etc.; the annealing time is 0.5~2h, for example 0.5h, 1h, 1.5h, 2h, etc.; and the annealing is water-cooled after completion.

[0052] In some preferred embodiments, the rolling deformation includes hot rolling and cold rolling.

[0053] In some preferred embodiments, the hot rolling is a multi-pass hot rolling; the total deformation of the hot rolling is 60~75%, for example 60%, 62%, 65%, 68%, 70%, 72%, 75%, etc.; the hot rolling temperature is 390~410℃, for example 390℃, 400℃, 410℃, etc.

[0054] In some preferred embodiments, the deformation amount per pass of hot rolling is 15-25%, for example, 15%, 18%, 20%, 22%, 25%, etc.; and the hot rolling is followed by water quenching.

[0055] In some preferred embodiments, the cold rolling is a multi-pass cold rolling; the total deformation of the cold rolling is 45-50%, for example 45%, 48%, 50%, etc.

[0056] In some preferred embodiments, the single-pass variation of the cold rolling is 5-15%, such as 5%, 8%, 10%, 12%, 15%, etc.; and no intermediate annealing is performed during the cold rolling process.

[0057] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to the accompanying drawings and preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0058] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0059] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0060] Comparative Example 1

[0061] This comparative example prepares an aluminum-magnesium alloy without CeO2, with the following composition by mass fraction: Mg 9.24%, Mn 0.69%, Ti 0.13%, Zr 0.14%, with the balance being Al and impurity elements. The specific preparation process includes the following steps:

[0062] Step 1: Melting and casting of aluminum-magnesium alloy

[0063] Pure Al ingots, Al-20Mn master alloy, Al-10Zr master alloy, and Al-5Ti-B master alloy were sequentially added to a melting furnace for the first stage of hot melting treatment at a temperature of 780°C to obtain an aluminum alloy melt. The aluminum alloy melt was then cooled to 720°C, and pure Mg ingots were added to it. The mixture was stirred and stirred to obtain an aluminum-magnesium alloy melt. The aluminum-magnesium alloy melt was then refined in hexachloroethane. After degassing, the mixture was stirred and refined for 12 minutes. After refining, the temperature was raised to 780°C and allowed to stand for 15 minutes. After standing, the aluminum-magnesium alloy melt was cooled to 720°C and cast to obtain an aluminum-magnesium alloy ingot.

[0064] Step 2: Homogenization

[0065] The aluminum-magnesium alloy ingots are first milled to a thickness of 12mm. Then they are placed in a heat treatment furnace for homogenization treatment at a temperature of 400℃ for 24 hours. After homogenization treatment, they are immediately water-cooled.

[0066] Step 3: Rolling Deformation

[0067] The homogenized aluminum-magnesium alloy ingots are first subjected to multiple hot rolling passes at a temperature of 400℃. After four hot rolling passes, the thickness of the sheet is 4.4mm. Immediately after hot rolling, the sheet is water quenched and then cold rolled. The thickness of the sheet after cold rolling is 2.2mm, and no intermediate annealing is performed. The cold rolling deformation is 50%.

[0068] Step 4: Stabilization Treatment

[0069] The stabilization annealing process is carried out at a temperature of 250℃ for 1 hour, followed by water cooling after annealing.

[0070] Step 5: Sensitization Treatment

[0071] To simulate the precipitation behavior of Mg atoms during the natural aging process of alloys, sensitization treatment is usually used to promote the precipitation of Mg atoms and thus increase the corrosion susceptibility of the alloy. This method is carried out after stabilization treatment, with the process being 150℃ / 7 days in an oil bath.

[0072] Example 1

[0073] This embodiment prepares an aluminum-magnesium alloy with 0.3 wt.% CeO2, with the following mass fraction composition: Mg 9.22%, Mn 0.66%, Ti 0.10%, Zr 0.12%, Ce 0.21%, and the balance being Al and impurity elements. The specific preparation process includes the following steps:

[0074] Step 1: Melting and casting of aluminum-magnesium alloy

[0075] Pure Al ingots, Al-20Mn master alloy, Al-10Zr master alloy, and Al-5Ti-B master alloy were sequentially added to a melting furnace for the first stage of hot melting treatment at a melt temperature of 780℃ to obtain an aluminum alloy melt. The obtained aluminum alloy melt was cooled to 720℃, and pure Mg ingots were added to it, mixed evenly and stirred to obtain an aluminum-magnesium alloy melt. The aluminum-magnesium alloy melt was heated to 780℃, and CeO2 powder coated with aluminum foil was pressed into the melt through a bell jar to ensure complete reaction and uniform mixing. The amount of CeO2 powder added was equal to the amount of Al ingots, Al... The total mass of the l-20Mn master alloy, Al-10Zr master alloy, Al-5Ti-B master alloy, Mg ingot and CeO2 powder is 0.3wt%, wherein the CeO2 powder is a newly obtained powder obtained by calcining cerium carbonate at 300~550℃; the Ce-containing aluminum-magnesium alloy melt is added to hexachloroethane for refining, first degassing and stirring thoroughly for 12min, after refining, the temperature is raised to 780℃ and left to stand for 15min; after standing, the Ce-containing aluminum-magnesium alloy melt is cooled to 720℃ and cast to obtain the Ce-containing aluminum-magnesium alloy ingot.

[0076] During the research process, the applicant discovered that if CeO2 is added to the aluminum melt first to form an aluminum alloy melt, CeO2 cannot integrate into the melt. However, by first adding Mg ingots to the aluminum melt to form an aluminum-magnesium alloy melt and then adding CeO2, CeO2 can integrate well into the melt. This indicates that the addition of high Mg content can achieve high efficiency in cerium oxide melting. Analysis suggests that this may be because the introduction of magnesium reduces the surface tension of the aluminum melt, thereby improving the wettability between the solid reactants and the liquid metal, thus enhancing the reaction kinetics at the solid-liquid interface and promoting CeO2 integration into the melt. Therefore, the applicant added CeO2 after dissolving Mg ingots and optimized the feeding sequence and melting temperature through research. A comparison of the CeO2 added in the raw materials and the Ce content in the final aluminum alloy shows that the utilization rate of the added CeO2 is extremely high, exceeding 90%.

[0077] Step 2: Homogenization

[0078] The aluminum-magnesium alloy ingots are first milled to a thickness of 12mm. Then they are placed in a heat treatment furnace for homogenization treatment at a temperature of 400℃ for 24 hours. After homogenization treatment, they are immediately water-cooled.

[0079] Step 3: Rolling Deformation

[0080] The homogenized aluminum-magnesium alloy ingots are first subjected to multiple hot rolling passes at a temperature of 400℃. After four hot rolling passes, the thickness of the sheet is 4.4mm. Immediately after hot rolling, the sheet is water quenched and then cold rolled. The thickness of the sheet after cold rolling is 2.2mm, and no intermediate annealing is performed. The cold rolling deformation is 50%.

[0081] Step 4: Stabilization Treatment

[0082] The stabilization annealing process is carried out at a temperature of 250℃ for 1 hour, followed by water cooling after annealing.

[0083] Step 5: Sensitization Treatment

[0084] To simulate the precipitation behavior of Mg atoms during the natural aging process of alloys, sensitization treatment is usually used to promote the precipitation of Mg atoms and thus increase the corrosion susceptibility of the alloy. This method is carried out after stabilization treatment, with the process being 150℃ / 7 days in an oil bath.

[0085] Example 2

[0086] This embodiment prepares an aluminum-magnesium alloy with 0.5 wt.% CeO2, with the following mass fraction composition: Mg 9.18%, Mn 0.67%, Ti 0.14%, Zr 0.11%, Ce 0.34%, and the balance being Al and impurity elements. The specific preparation process includes the following steps:

[0087] Step 1: Melting and casting of aluminum-magnesium alloy

[0088] Pure Al ingots, Al-20Mn master alloy, Al-10Zr master alloy, and Al-5Ti-B master alloy were sequentially added to a melting furnace for the first stage of hot melting treatment at a melt temperature of 780℃ to obtain an aluminum alloy melt. The obtained aluminum alloy melt was cooled to 720℃, and pure Mg ingots were added to it, mixed evenly and stirred to obtain an aluminum-magnesium alloy melt. The aluminum-magnesium alloy melt was heated to 780℃, and CeO2 powder coated with aluminum foil was pressed into the melt through a bell jar to ensure complete reaction and uniform mixing. The amount of CeO2 powder added was equal to the amount of Al ingots, Al... The total mass of the l-20Mn master alloy, Al-10Zr master alloy, Al-5Ti-B master alloy, Mg ingot and CeO2 powder is 0.5wt%, wherein the CeO2 powder is a newly obtained powder obtained by calcining cerium carbonate at 300~550℃; the Ce-containing aluminum-magnesium alloy melt is added to hexachloroethane for refining, first degassing and then stirring thoroughly for 12min; after refining, the temperature is raised to 780℃ and left to stand for 15min; after standing, the Ce-containing aluminum-magnesium alloy melt is cooled to 720℃ and cast to obtain the Ce-containing aluminum-magnesium alloy ingot.

[0089] Step 2: Homogenization

[0090] The aluminum-magnesium alloy ingots are first milled to a thickness of 12mm. Then they are placed in a heat treatment furnace for homogenization treatment at a temperature of 400℃ for 24 hours. After homogenization treatment, they are immediately water-cooled.

[0091] Step 3: Rolling Deformation

[0092] The homogenized aluminum-magnesium alloy ingots are first subjected to multiple hot rolling passes at a temperature of 400℃. After four hot rolling passes, the thickness of the sheet is 4.4mm. Immediately after hot rolling, the sheet is water quenched and then cold rolled. The thickness of the sheet after cold rolling is 2.2mm, and no intermediate annealing is performed. The cold rolling deformation is 50%.

[0093] Step 4: Stabilization Treatment

[0094] The annealing process is carried out at a temperature of 250℃ for 1 hour, followed by water cooling after annealing.

[0095] Step 5: Sensitization Treatment

[0096] To simulate the precipitation behavior of Mg atoms during the natural aging process of alloys, sensitization treatment is usually used to promote the precipitation of Mg atoms and thus increase the corrosion susceptibility of the alloy. This method is carried out after annealing, with the process being 150℃ / 7 days in an oil bath.

[0097] Transmission electron microscopy (TEM) analysis was performed on the aluminum-magnesium alloy obtained in step four. The TEM bright-field image, selected area electron diffraction (SED) pattern, and EDS analysis of the bulk second phase in the alloy are shown below. Figure 1 As shown in (a) and (b), the EDS analysis is as follows: Figure 2 As shown in (a) and (b).

[0098] The TEM image shows that the bulky second phase has a side length of approximately 6 μm. Selected area electron diffraction (SED) patterns of this phase were analyzed and calibrated. Figure 1 As shown in (b), energy dispersive spectroscopy analysis was performed on the STEM image, and the results are as follows. Figure 2 As shown. The bulky second phase in the alloy is determined to be Al. 20 Mn2Ce phase, Al 20 The Mn2Ce phase belongs to the face-centered cubic structure, and its space group is Fd. m, whose unit cell size is a=b=c=1.448nm, and whose calibration results are similar to Al 20 The standard spectrum of the Mn2Ce phase is consistent, indicating that this phase is Al. 20 Mn₂Ce phase. Al 20 The Mn2Ce phase can improve the high temperature resistance and pitting corrosion resistance of aluminum alloys.

[0099] During TEM analysis, another Ce-containing phase was also found in the alloy, as shown in the bright-field TEM image. Figure 3 As shown, elemental surface scanning of the bright-field image region in STEM mode revealed that... Figure 3 The red box in the middle shows a Ce-enriched region, and the EDS spot scan results of this cerium-enriched phase are shown above. Figure 4As shown in (b), zoom in on this area for observation, as... Figure 5 As shown in (a), this phase exhibits a distinct phase boundary, approximately 600 nm in length, and is elliptical in shape. To determine the phase, selected area electron diffraction (SAED) pattern analysis and calibration were performed on this phase. Figure 5 (b) ), the results are consistent with Al 13 The standard spectrum of the CeMg6 phase is consistent (PDF#01-085-6518), indicating that this phase is Al. 13 CeMg6 phase, Al 13 The CeMg6 phase belongs to the hexagonal crystal system, space group P63 / mmc(194), with cell sizes a = 0.5525 nm, b = 0.5525 nm, c = 1.7866 nm, α = 90 °, β = 90 °, γ = 120 °. 13 The CeMg6 phase is approximately 600 nm in size and elliptical in shape. These nano- to submicron-sized, dispersed second-phase particles effectively hinder dislocation movement, thereby improving the alloy's strength. Since the β-Al3Mg2 phase is anodic relative to the matrix, it undergoes selective dissolution, increasing the Al-Mg alloy's susceptibility to intergranular corrosion. 13 The formation of the CeMg6 phase consumes some Mg elements, which may reduce the amount of β-Al3Mg2 phase continuously distributed in a network at the grain boundaries, reduce the growth kinetics of the β phase, and improve the alloy's resistance to intergranular corrosion.

[0100] Analysis suggests that the formation of the two second phases in the magnesium alloy prepared by this invention may be related to the following factors: 1. Ce is nascent CeO2 powder obtained from the decomposition of cerium carbonate, added to the melt. The nascent Ce atoms obtained through thermal reduction have high activity, causing the system to enter a non-equilibrium, high-free-energy metastable state. Ce atoms have high thermodynamic activity and strong chemical driving force. At the beginning of solidification, [Mn] and [Ce] atoms in the melt diffuse and aggregate to form Al. 20 Mn₂Ce crystal nuclei grow into coarse primary phases, a process that consumes a large number of [Ce] and [Mn] atoms in the melt. However, due to the high activity of the initial Ce, the Al-Mn-Ce phase cannot consume all of the Ce, and a large number of Ce atoms are still pushed into the interdendritic region and enriched by the subsequently solidified α-Al dendrites. At the end of solidification, the interdendritic liquid phase contains both highly active Ce and a high concentration of Mg. This micro-region composition satisfies the thermodynamic conditions for peritectic reaction, thus successfully generating Al. 13 1. CeMg6 phase; 2. It is related to the feeding sequence of materials during the smelting process and the temperature control during the feeding process; 3. The hot rolling + cold rolling of this invention introduces a large number of crystal defects such as dislocations and grain boundaries, which promote the formation of Al 134. Precipitation of the CeMg6 phase; heat treatment at a relatively low temperature, such as 250°C, provides sufficient diffusion capacity for Ce and Mg atoms, enabling them to segregate and form a new Al phase. 13 CeMg6 phase.

[0101] And for commercially available CeO2 (such as Figure 6 (a) and the newly formed CeO2 obtained by calcining cerium carbonate (such as...) Figure 6 (b) Comparative analysis revealed that the newly formed CeO2 obtained from calcined cerium carbonate had smaller and more porous particle sizes, resulting in a larger specific surface area. This may provide higher reactivity for the newly formed Ce atoms, thereby benefiting Al. 13 Successful formation of the CeMg6 phase.

[0102] Table 1. Room temperature mechanical properties of stabilized aluminum-magnesium alloys

[0103]

[0104] As shown in Table 1, compared with Comparative Example 1 without CeO2, the tensile strength and yield strength of the aluminum-magnesium alloy in Example 1 with 0.3 wt.% CeO2 were 501 MPa and 345 MPa, respectively, representing increases of 3.7% and 2.7% compared to the aluminum-magnesium alloy in Comparative Example 1. Example 2, with 0.5 wt.% CeO2, had tensile strength and yield strength of 515 MPa and 368 MPa, respectively, representing increases of 6.6% and 9.5% compared to the aluminum-magnesium alloy in Comparative Example 1. It can be seen that the addition of CeO2 can improve the room temperature strength of aluminum-magnesium alloys to a certain extent, which is related to the Al formed in the aluminum-magnesium alloy. 20 Mn2Ce, Al 13 This is related to the CeMg6-reinforced phase.

[0105] Table 2. High-temperature (150℃) mechanical property data of stabilized aluminum-magnesium alloys

[0106]

[0107] As shown in Table 2, compared with Comparative Example 1 without CeO2, the tensile strength and yield strength of the aluminum-magnesium alloys in Examples 1 and 2 with 0.3 wt.% CeO2 and 0.5 wt.% CeO2 respectively were improved at high temperatures. This indicates that adding CeO2 can improve the high-temperature strength of aluminum-magnesium alloys to a certain extent. This is due to the presence of the second-phase reinforcing phase Al in the aluminum-magnesium alloy. 20 This is caused by the high-temperature strengthening effect of the Mn2Ce phase.

[0108] The stabilized and sensitized aluminum-magnesium alloys obtained in Comparative Example 1 and Examples 1-2 were subjected to immersion tests. The mass loss rate per unit area of ​​the alloys after immersing the samples in a 3.5 wt.% NaCl solution at 25°C for 7 days was calculated. The test results are shown in Table 3.

[0109] Table 3 Mass loss rate of pitting corrosion in aluminum-magnesium alloys

[0110]

[0111] As shown in Table 3, compared with Comparative Example 1 without CeO2, Example 1 with 0.3 wt.% CeO2 and Example 2 with 0.5 wt.% CeO2 showed lower pitting corrosion resistance rates in both states, indicating that the addition of CeO2 can improve the pitting corrosion resistance of aluminum-magnesium alloys. Analysis revealed that the intermetallic compound (Al6Mn) has a higher potential relative to the aluminum matrix, initiating pitting corrosion through preferential dissolution of the surrounding aluminum matrix. The remaining Mn-rich intermetallic compound eventually detaches from the alloy surface, forming coreless pits. This phenomenon is exacerbated in high-magnesium aluminum alloys, such as... Figure 7 As shown. The local potential of the Al-Mn phase with Ce segregation changes, and experiments have shown that this segregation phenomenon reduces the inducing effect of localized corrosion on the alloy plate, such as... Figure 8 As shown. The second phase Al in the aluminum-magnesium alloy of the present invention. 20 The Mn2Ce phase can improve pitting corrosion resistance. As shown in Tables 1-3, the aluminum-magnesium alloy with a special second-phase structure synthesized in this invention improves pitting corrosion resistance while maintaining alloy strength. To further observe the corrosion behavior of the alloy, the pitting morphology of the sensitized state comparative example 1 and example 1 was characterized by SEM, as shown below. Figure 7 , Figure 8 As shown, the pitting depth of the Ce-containing aluminum-magnesium alloy is significantly smaller, indicating that the alloy has a stronger ability to resist localized corrosion.

[0112] The stabilized and sensitized aluminum-magnesium alloys obtained in Comparative Example 1 and Examples 1-2 were subjected to immersion tests. The mass loss rate per unit area of ​​the alloy was calculated after the sample was placed in a 70% HNO3 solution at 25°C for 24 hours. The test results are shown in Table 4.

[0113] Table 4 Mass Loss Due to Intergranular Corrosion in Aluminum-Magnesium Alloys

[0114]

[0115] As shown in Table 4, compared with Comparative Example 1 without CeO2, the mass loss rate of intergranular corrosion resistance in Example 1 with 0.3 wt.% CeO2 and Example 2 with 0.5 wt.% CeO2 was lower in both states than in Comparative Example 1, indicating that the addition of CeO2 can improve the intergranular corrosion resistance of the alloy. Analysis revealed that this is due to the presence of the second phase Al in the aluminum-magnesium alloy. 13 The formation of the CeMg6 phase can reduce the proportion of the β phase, thereby improving the resistance to intergranular corrosion. To further observe the alloy's resistance to intergranular corrosion, Figure 9 , Figure 10 The figures show the intergranular corrosion cross-sections of the stabilized alloys and the sensitized alloys prepared in Comparative Example 1 and Examples 1-2, respectively. As can be seen from the figures, the intergranular corrosion resistance of the aluminum-magnesium alloys in Examples 1-2 is significantly improved.

[0116] This invention provides a high-strength, highly corrosion-resistant, and heat-resistant Ce-containing aluminum-magnesium alloy material and its preparation method. The aluminum-magnesium alloy has the following mass composition: Mg: 8.3~9.6%, Mn: 0.4~0.8%, Ti: 0.05~0.15%, Zr: 0.05~0.2%, CeO2: 0.1~0.5%, with the balance being Al and unavoidable impurities. By adding newly formed CeO2 during the smelting process and controlling the synthesis process, Al with a second phase can be synthesized. 13 CeMg6, Al 20 The Mn2Ce high-Mg aluminum alloy not only possesses excellent mechanical properties due to its high Mg content, but also exhibits significantly improved high-temperature resistance, pitting corrosion resistance, and intergranular corrosion resistance due to the presence of a second phase. Furthermore, the use of CeO2 to introduce rare earth Ce elements can reduce production costs.

[0117] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing high-strength, high-corrosion-resistant aluminum-magnesium alloy, characterized in that, The aluminum-magnesium alloy, by mass percentage, contains 8.3-9.6% Mg, 0.4-0.8% Mn, 0.05-0.15% Ti, 0.05-0.2% Zr, and 0.1-0.5% Ce, with the balance being Al and unavoidable impurities. The aluminum-magnesium alloy contains Al. 13 CeMg6 phase; the preparation method includes: Al ingots, Al-20Mn master alloy, Al-10Zr master alloy and Al-5Ti-B master alloy are sequentially added into the melting furnace for the first stage of hot melting treatment. The melt temperature is 760~780℃ to obtain aluminum alloy melt. The aluminum alloy melt is cooled to 710~730℃, pure Mg ingots are added to it, and the mixture is stirred to obtain an aluminum-magnesium alloy melt. The aluminum-magnesium alloy melt is heated to 780~800℃, CeO2 powder is added to it, and the mixture is stirred to obtain a Ce-containing aluminum-magnesium alloy melt. After refining the Ce-containing aluminum-magnesium alloy melt, the temperature is raised to 760~780℃ and left to stand. After standing, the Ce-containing aluminum-magnesium alloy melt is cast to obtain a high-strength, high-corrosion-resistant aluminum-magnesium alloy.

2. The method for preparing high-strength, high-corrosion-resistant aluminum-magnesium alloy as described in claim 1, characterized in that, The CeO2 powder is a newly formed powder obtained by thermal decomposition of cerium carbonate; the thermal decomposition temperature is 300~550℃; the CeO2 is added by pressing the CeO2 powder wrapped in aluminum foil into the melt through a bell jar; the amount of CeO2 powder added is 0.1~0.5% of the total mass of Al ingot, Al-20Mn master alloy, Al-10Zr master alloy, Al-5Ti-B master alloy, Mg ingot, and CeO2 powder.

3. The method for preparing high-strength, high-corrosion-resistant aluminum-magnesium alloy as described in claim 1, characterized in that, The refining agent used is hexachloroethane; the amount of hexachloroethane used is 0.2-0.4% of the total mass of Al ingots, Al-20Mn master alloy, Al-10Zr master alloy, Al-5Ti-B master alloy, Mg ingots and CeO2 powder; the refining time is 10-30 minutes; the refining includes: adding hexachloroethane to Ce-containing aluminum-magnesium alloy melt for refining; The settling time is 10-20 minutes; The Ce-containing aluminum-magnesium alloy melt is first cooled to 700~720℃ before being cast; the casting is a metal mold casting.

4. The method for preparing high-strength, high-corrosion-resistant aluminum-magnesium alloy as described in claim 1, characterized in that, It also includes the step of processing aluminum-magnesium alloy ingots; the processing includes: sequentially performing milling, homogenization, rolling deformation and annealing on the aluminum-magnesium alloy ingots.

5. The method for preparing high-strength, high-corrosion-resistant aluminum-magnesium alloy as described in claim 4, characterized in that, The homogenization treatment temperature is 390~410℃; the homogenization treatment holding time is 18~30h; and water cooling is performed immediately after the homogenization treatment. The annealing temperature is 230~280℃; the annealing time is 0.5~2h; and the annealing is completed by water cooling.

6. The method for preparing high-strength, high-corrosion-resistant aluminum-magnesium alloy as described in claim 4, characterized in that, The rolling deformation includes hot rolling and cold rolling; The hot rolling is a multi-pass hot rolling; the total deformation of the hot rolling is 60~75%; the hot rolling temperature is 390~410℃; The cold rolling is a multi-pass cold rolling process; the total deformation of the cold rolling is 45-50%.

7. The method for preparing high-strength, high-corrosion-resistant aluminum-magnesium alloy as described in claim 6, characterized in that, The deformation per pass of the hot rolling is 15-25%; the hot rolling is followed by water quenching. The single-pass variation of the cold rolling process is 5-15%; no intermediate annealing is performed during the cold rolling process.

8. A high-strength, high-corrosion-resistant aluminum-magnesium alloy, characterized in that, It is prepared by the preparation method described in any one of claims 1 to 7.

9. The high-strength, high-corrosion-resistant aluminum-magnesium alloy as described in claim 8, characterized in that, The aluminum-magnesium alloy also contains Al. 20 Mn2Ce phase; The aluminum-magnesium alloy contains 0.15-0.4% Ce by mass percentage.

10. The high-strength, high-corrosion-resistant aluminum-magnesium alloy as described in claim 8 or 9, characterized in that, The aluminum-magnesium alloy is in the form of sheet metal.

Images