High-toughness Al-V-Ti-Mn-Mg series aluminum alloy and preparation method thereof

Abstract

The invention relates to the technical field of aluminum alloy materials, in particular to a high-strength and high-toughness Al-V-Ti-Mn-Mg series aluminum alloy and a preparation method thereof.The high-strength and high-toughness Al-V-Ti-Mn-Mg series aluminum alloy mainly comprises, by mass, 0.05%-0.5% of V, 0.05%-0.5% of Ti, 0.4%-1.2% of Mn, 0.3%-1.2% of Mg, 0.1%-0.3% of Cr, smaller than or equal to 0.15% of inevitable impurity elements, the balance Al and inevitable impurities, and the balance Al and inevitable impurities. And at least one of Sc, Zr and Er, less than or equal to 0.2% of Sc, less than or equal to 0.2% of Zr, less than or equal to 0.2% of Er, and the balance of Al. The high-strength and high-toughness Al-V-Ti-Mn-Mg series aluminum alloy provided by the invention is less in coarse second-phase grains and excellent in anodic oxidation effect, and has excellent corrosion resistance and a small-color-difference coloring effect after anodic oxidation.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aluminum alloy materials, and particularly relates to a high-strength and high-toughness Al-V-Ti-Mn-Mg aluminum alloy and a preparation method thereof. BACKGROUND

[0002] The existing Al-Mn-Mg aluminum alloy adds a large amount of elements Mn and Mg for improving the strength and toughness, but the elements Mn and Mg easily cause the increase of coarse second-phase grains in the aluminum alloy during the casting process. In the anodic oxidation process, the difference in electrochemical properties between the coarse second-phase grains and the aluminum matrix causes the uneven local oxidation rate, thereby causing the problems of thickness fluctuation of the oxidation film, increase of micropore defects and the like, further affecting the corrosion resistance of the aluminum alloy, and existing coloring problems such as large color difference and uneven coloring.

[0003] Therefore, it is urgent to solve the problem of uneven local oxidation rate caused by the excessive coarse second-phase grains of the elements Mn and Mg in the aluminum alloy. SUMMARY

[0004] Based on the deficiencies of the prior art, the present application provides a high-strength and high-toughness Al-V-Ti-Mn-Mg aluminum alloy and a preparation method thereof, and aims to solve the problem of uneven local oxidation rate caused by the excessive coarse second-phase grains of the elements Mn and Mg in the aluminum alloy.

[0005] In order to achieve the above object, the present application provides the following technical scheme:

[0006] The high-strength and high-toughness Al-V-Ti-Mn-Mg aluminum alloy comprises, by mass percentage, 0.05-0.5% V, 0.05-0.5% Ti, 0.4-1.2% Mn, 0.3-1.2% Mg, 0.1-0.3% Cr, unavoidable impurity elements ≤0.15%, and at least one of Sc, Zr and Er, wherein Sc ≤0.2%, Zr ≤0.2%, and Er ≤0.2%, and the balance is Al.

[0007] In some embodiments, the high-strength and high-toughness Al-V-Ti-Mn-Mg aluminum alloy comprises, by mass percentage, 0.1-0.5% V, 0.3-0.5% Ti, 0.4-0.8% Mn, 0.3-0.8% Mg, 0.1-0.3% Cr, unavoidable impurity elements ≤0.15%, and at least one of Sc, Zr and Er, wherein Sc ≤0.2%, Zr ≤0.2%, and Er ≤0.2%, and the balance is Al.

[0008] In some embodiments, in the high-strength and toughness Al-V-Ti-Mn-Mg aluminum alloy, the sum of the mass percentages of Sc, Zr, and Er is less than or equal to 0.3%.

[0009] The second object of the present invention is to provide a high-strength and toughness Al-V-Ti-Mn-Mg aluminum alloy and a preparation method thereof, aiming to provide a preparation method of the high-strength and toughness Al-V-Ti-Mn-Mg aluminum alloy. Based on this, the present invention provides the following technical solutions:

[0010] A method for preparing the high-strength and toughness Al-V-Ti-Mn-Mg aluminum alloy, the method comprising the following steps:

[0011] Prepare raw materials according to the composition of the high-strength and toughness Al-V-Ti-Mn-Mg aluminum alloy;

[0012] Preheating, melting, refining and degassing the raw materials to obtain a metal melt;

[0013] The metal melt is subjected to extrusion casting and aging treatment to obtain the high-strength and toughness Al-V-Ti-Mn-Mg aluminum alloy, and the aging treatment includes: heating after a first aging treatment and performing a second aging treatment.

[0014] In some embodiments, during the extrusion casting, the temperature of the metal melt is 730-740° C.; and / or the pressure of the extrusion casting is 50-100 MPa; and / or the holding time of the extrusion casting is 15-30 s.

[0015] In some embodiments, the first aging treatment temperature is 120-140° C.; and / or, the first aging treatment time is 1-2 hours; and / or, the heating rate of the heating is 5-10° C. / min; and / or, the second aging treatment temperature is 300-330° C.; and / or, the second aging treatment time is 2-4 hours.

[0016] In some embodiments, the preparation method comprises: after the aging treatment, further performing anodizing, the anodizing temperature is 18 to 22° C., and the anodizing time is 30 to 60 minutes.

[0017] In some embodiments, the current density of the anodization is 1.0 to 1.5 A / dm 2 ; and / or, the voltage of the anodization is 12 to 18V.

[0018] In some embodiments, the preparation method includes: after the anodizing, further performing coloring, and the colored electrolyte contains SnSO4 with a mass volume concentration of 10 to 15 g / L and NiSO4 with a mass volume concentration of 5 to 8 g / L.

[0019] In some embodiments, the coloring is performed using alternating current; and / or the current density of the alternating current is 0.2 to 0.5 A / dm 2 ; and / or, the voltage of the alternating current is 10 to 15 V; and / or, the coloring temperature is 20 to 25° C.; and / or, the coloring time is 2 to 5 min.

[0020] The benefit of the present invention lies in that: by reasonably matching the components of the high-strength and toughness Al-V-Ti-Mn-Mg aluminum alloy, the present invention can reduce the coarse second-phase grains in the high-strength and toughness Al-V-Ti-Mn-Mg aluminum alloy while maintaining the high strength and toughness of the Al-V-Ti-Mn-Mg aluminum alloy, and achieve the effect of refining the grains and inhibiting component segregation, thereby effectively reducing the generation of surface defects such as micropores and cracks, reducing the porosity of the high-strength and toughness Al-V-Ti-Mn-Mg aluminum alloy, and avoiding the uneven local oxidation rate of the anodic oxidation caused by the coarse second-phase grains, thereby enabling the high-strength and toughness Al-V-Ti-Mn-Mg aluminum alloy to obtain a highly dense and uniform oxide film after anodic oxidation, effectively improving the corrosion resistance of the high-strength and toughness Al-V-Ti-Mn-Mg aluminum alloy, and reducing color difference. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a SEM image of the aluminum alloy product prepared in Example 1 of the present invention;

[0022] Figure 2 This is a physical picture of the aluminum alloy product prepared in Example 1 of the present invention after anodizing and coloring. DETAILED DESCRIPTION

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below. It should be understood that the following embodiments are merely for explanation and not for limitation. Unless otherwise specified, all technical and scientific terms used herein have the common meanings in the field to which the claimed subject matter belongs.

[0024] The existing Al-Mn-Mg aluminum alloy adds a large amount of Mn, Mg and other elements for improving the strength and toughness to meet the high strength and toughness, but the Mn, Mg and other elements easily cause the increase of coarse second phase grains in the aluminum alloy during the casting process; the difference in electrochemical properties between the coarse second phase grains and the aluminum matrix causes the uneven local oxidation rate during the anodic oxidation process, thereby causing the problems of thickness fluctuation of the oxidation film, the increase of micropore defects and other problems, further affecting the corrosion resistance of the aluminum alloy, and the coloring problems of large color difference and uneven coloring.

[0025] Therefore, it is urgent to solve the problem of uneven local oxidation rate caused by the excessive coarse second phase grains of the Mn and Mg elements in the aluminum alloy.

[0026] Based on the deficiencies of the prior art, the present application provides a high strength and toughness Al-V-Ti-Mn-Mg aluminum alloy and a preparation method thereof, aiming to solve the problem of uneven local oxidation rate caused by the excessive coarse second phase grains of the Mn and Mg elements in the aluminum alloy.

[0027] In order to achieve the above purpose, the present application provides the following technical solutions:

[0028] A high strength and toughness Al-V-Ti-Mn-Mg aluminum alloy, the composition of the high strength and toughness Al-V-Ti-Mn-Mg aluminum alloy comprises, by mass percentage: 0.05-0.5% V, 0.05-0.5% Ti, 0.4-1.2% Mn, 0.3-1.2% Mg, 0.1-0.3% Cr, unavoidable impurity elements ≤0.15%, and at least one of Sc, Zr and Er, and Sc ≤0.2%, Zr ≤0.2%, Er ≤0.2%, and the balance is Al.

[0029] In some embodiments, the composition of the high strength and toughness Al-V-Ti-Mn-Mg aluminum alloy comprises, by mass percentage: 0.1-0.5% V, 0.3-0.5% Ti, 0.4-0.8% Mn, 0.3-0.8% Mg, 0.1-0.3% Cr, unavoidable impurity elements ≤0.15%, and at least one of Sc, Zr and Er, and Sc ≤0.2%, Zr ≤0.2%, Er ≤0.2%, and the balance is Al.

[0030] V and Ti elements form nano-Al-V and Al3Ti phases in high-strength and tough Al-V-Ti-Mn-Mg aluminum alloys, which refine grains and provide dispersion strengthening, thereby improving the tensile strength of high-strength and tough Al-V-Ti-Mn-Mg aluminum alloys. Mn is a key element in high-strength and tough Al-V-Ti-Mn-Mg aluminum alloys, effectively inhibiting the recrystallization process and raising the recrystallization temperature. Furthermore, Mn forms MBAl6 as dispersed particles in high-strength and tough Al-V-Ti-Mn-Mg aluminum alloys, hindering the growth of recrystallized grains, significantly refining the recrystallized grains and improving the overall performance of high-strength and tough Al-V-Ti-Mn-Mg aluminum alloys. Mg can significantly improve the strength, tensile strength, corrosion resistance, and plasticity of high-strength and tough Al-V-Ti-Mn-Mg aluminum alloys. Cr can strengthen high-strength and tough Al-V-Ti-Mn-Mg aluminum alloys and improve the toughness of high-strength and tough Al-V-Ti-Mn-Mg aluminum alloys; at the same time, Cr can form a dense oxide film on the surface of high-strength and tough Al-V-Ti-Mn-Mg aluminum alloys, thereby improving the corrosion resistance of high-strength and tough Al-V-Ti-Mn-Mg aluminum alloys.

[0031] Sc can significantly improve the strength, plasticity, welding performance, high temperature performance and corrosion resistance of high strength and toughness Al-V-Ti-Mn-Mg aluminum alloys. Zr can increase the recrystallization temperature of high strength and toughness Al-V-Ti-Mn-Mg aluminum alloys, improve the stability of the solid solution, and improve the welding performance of high strength and toughness Al-V-Ti-Mn-Mg aluminum alloys. The rare earth element Er has the effects of refining grains, reducing the secondary dendrite spacing, reducing the surface tension of the melt, and increasing fluidity when preparing high strength and toughness Al-V-Ti-Mn-Mg aluminum alloys; and Er can replace part of Sc in high strength and toughness Al-V-Ti-Mn-Mg aluminum alloys, thereby reducing costs. Furthermore, the combination of Sc and Zr inhibits the crystallization of high strength and toughness Al-V-Ti-Mn-Mg aluminum alloys and refines the grains; at the same time, Zr can promote the precipitation of dispersed and fine secondary Al3Sc; Zr can also replace the scandium atoms in Al3Sc to form Al3(Sc 1-x , Zr x ) phase particles, which not only have the effect of inhibiting recrystallization and dispersion strengthening, but also act as heterogeneous crystal nuclei during the solidification process of high-strength and tough Al-V-Ti-Mn-Mg aluminum alloys to further refine the grains.

[0032] The present invention replaces part of the Mn and Mg elements by adding a small amount of V, Ti, and Cr elements, thereby achieving the synergistic enhancement of the toughness of the high-strength and tough Al-V-Ti-Mn-Mg aluminum alloy by multiple elements, while avoiding the problems of an increase in coarse second-phase grains in the high-strength and tough Al-V-Ti-Mn-Mg aluminum alloy due to excessive Mn and Mg elements, which triggers uneven local oxidation rate of anodization, resulting in reduced uniformity of the anodized film of the high-strength and tough Al-V-Ti-Mn-Mg aluminum alloy and increased porosity; and the present invention further improves the toughness of the high-strength and tough Al-V-Ti-Mn-Mg aluminum alloy through the grain refinement and inhibition of component segregation effects of Sc, Zr, and Er. In summary, the present invention reasonably matches the components of high-strength and toughness Al-V-Ti-Mn-Mg aluminum alloy, while maintaining the high strength and toughness of high-strength and toughness Al-V-Ti-Mn-Mg aluminum alloy, achieving the effect of refining grains and inhibiting component segregation, thereby reducing the coarse second-phase grains in the high-strength and toughness Al-V-Ti-Mn-Mg aluminum alloy, effectively reducing the generation of defects such as micropores and cracks, reducing the porosity of the high-strength and toughness Al-V-Ti-Mn-Mg aluminum alloy, and avoiding the uneven local oxidation rate of anodizing caused by coarse second-phase grains, thereby forming a uniform and good oxide film on the surface of the high-strength and toughness Al-V-Ti-Mn-Mg aluminum alloy after anodizing, greatly improving the corrosion resistance of the high-strength and toughness Al-V-Ti-Mn-Mg aluminum alloy, and making it have an excellent coloring effect, meeting the application scenarios with high requirements for appearance decoration.

[0033] In some embodiments, in the high-strength and toughness Al-V-Ti-Mn-Mg aluminum alloy, the sum of the mass percentages of Sc, Zr, and Er is less than or equal to 0.3%.

[0034] The present invention utilizes Sc, Zr, and Er in a flexible combination, adapting to varying product strength-cost requirements and offering a wide range of applications. Furthermore, to save costs, Zr and Er can partially replace the single, expensive Sc element, achieving grain refinement and suppressing component segregation.

[0035] The second object of the present invention is to provide a high-strength and tough Al-V-Ti-Mn-Mg series aluminum alloy and a method for preparing the same, and to provide a method for preparing the high-strength and tough Al-V-Ti-Mn-Mg series aluminum alloy. Based on this, the present invention provides the following technical solutions:

[0036] A method for preparing the high-strength and toughness Al-V-Ti-Mn-Mg aluminum alloy, the method comprising the following steps:

[0037] S1: Prepare raw materials according to the composition of the high-strength and toughness Al-V-Ti-Mn-Mg aluminum alloy.

[0038] In some embodiments, the raw material comprises pure Al, a master alloy, or pure Mg.

[0039] In some embodiments, the master alloy comprises at least five of Al-V master alloy, Al-5%Ti-B master alloy, Al-Mn master alloy, Al-Cr master alloy, Al-Sc master alloy, Al-Zr master alloy, and Al-Er master alloy.

[0040] In some embodiments, the master alloy comprises at least five of Al-10%V master alloy, Al-5%Ti-B master alloy, Al-10%Mn master alloy, Al-10%Cr master alloy, Al-2%Sc master alloy, Al-10%Zr master alloy, and Al-10%Er master alloy.

[0041] The Al-5% Ti-B master alloy refines the grain size of high-strength and tough Al-V-Ti-Mn-Mg aluminum alloys, thereby improving the strength and toughness of high-strength and tough Al-V-Ti-Mn-Mg aluminum alloys. Furthermore, the Al-5% Ti-B master alloy has no negative effect on anodization, and does not affect anodization or coloring. The present invention introduces V, Ti, Mn, Cr, Sc, Zr, and Er into the high-strength and tough Al-V-Ti-Mn-Mg aluminum alloy by using Al-10% V, Al-5% Ti-B, Al-10% Mn, Al-10% Cr, Al-2% Sc, Al-10% Zr, and Al-10% Er, respectively, to ensure the stability and consistency of the element content of the high-strength and tough Al-V-Ti-Mn-Mg aluminum alloy.

[0042] S2: preheating, melting, refining and degassing the raw materials to obtain a metal melt.

[0043] In some embodiments, the preheating temperature is 200°C.

[0044] Preheating can fully remove moisture from the raw materials and reduce quality fluctuations caused by factors such as temperature differences, thereby making the performance of the raw materials more stable and helping to improve the quality of the final product. In addition, preheating helps the raw materials reach the temperature required for smelting more quickly, accelerates the smelting reaction, and enables the raw materials to mix and react more fully, thereby improving preparation efficiency and aluminum alloy quality.

[0045] In some embodiments, during the melting process, the pure Al is melted to obtain a first melt; then the master alloy is added and melted to obtain a third melt; and finally, pure Mg is added and melted.

[0046] In some embodiments, the melting temperature of pure Al is 750-780°C; and / or, when the intermediate alloy is melted, the first melt temperature is 750-780°C; and / or, after adding the intermediate alloy, the temperature is kept warm for 15-45 minutes; and / or, when the pure Mg is melted, the third melt temperature is 700°C; and / or, after adding the pure Mg, the temperature is kept warm for 15-20 minutes.

[0047] The present invention melts the high melting point alloy first, then cools down to melt the low melting point alloy, melts the rare earth element intermediate alloy, and finally cools down to add Mg, which can effectively reduce the burning loss of elements caused by long-term melting.

[0048] In some embodiments, the refining and degassing is performed by an inert gas; and / or the inert gas comprises nitrogen and / or argon; and / or the refining and degassing temperature is 750°C; and / or the refining and degassing time is 10 to 20 minutes; and / or the refining and degassing is allowed to stand for 15 to 20 minutes.

[0049] In some embodiments, the refining degassing is performed with argon.

[0050] At high temperatures, molten aluminum alloys easily combine with oxygen in the air to form oxidized inclusions such as aluminum oxide, which seriously affects the quality of the aluminum alloy. Refining and degassing can effectively remove gases and oxidized inclusions from the molten aluminum alloy, thereby reducing the occurrence of defects and improving the quality and performance of the aluminum alloy.

[0051] In some embodiments, the refining and degassing process further includes skimming before and after the standing process.

[0052] The present invention removes oxide inclusions on the surface of the aluminum alloy liquid by slag skimming, effectively reduces the impurity content, improves the purity of the aluminum alloy liquid, and makes the performance of the high-strength and tough Al-V-Ti-Mn-Mg series aluminum alloy more stable.

[0053] S3: The metal melt is subjected to extrusion casting and aging treatment to obtain the high-strength and toughness Al-V-Ti-Mn-Mg aluminum alloy.

[0054] In some embodiments, during the extrusion casting, the temperature of the metal melt is 730-740° C.; and / or the pressure of the extrusion casting is 50-100 MPa; and / or the holding time of the extrusion casting is 15-30 s.

[0055] In some embodiments, during the squeeze casting process, the mold is preheated to 250°C.

[0056] The invention prepares a high-strength and tough Al-V-Ti-Mn-Mg series aluminum alloy with dense structure, excellent performance and high surface quality through an extrusion casting near-net-shape process. This is because in extrusion casting, the use of high pressure can force the aluminum alloy liquid to fill the mold accurately and quickly, which is conducive to the one-time net forming of thin-walled, deep-cavity, complex and other structural parts. The prepared components have low porosity and high dimensional accuracy, thereby saving subsequent cutting processing costs; at the same time, the present invention uses high pressure in extrusion casting, which helps to increase the solid solubility of elements such as V, Ti, Mn, Mg in the aluminum matrix when the aluminum alloy liquid solidifies, achieves supersaturation of strengthening elements and rapid cooling of the metal melt, is beneficial to grain size refinement, and promotes uniform distribution of precipitated phase grains, thereby achieving the effect of inhibiting component segregation and reducing the content of coarse second-phase grains; and compared with traditional casting processes, extrusion casting can also inhibit the generation of surface oxide scale and cold shut defects of high-strength and tough Al-V-Ti-Mn-Mg aluminum alloys, so that the surface quality of the prepared high-strength and tough Al-V-Ti-Mn-Mg aluminum alloys is high, thereby simplifying the pre-treatment required for anodizing.

[0057] In some embodiments, the aging treatment comprises: heating up after a first aging treatment and performing a second aging treatment.

[0058] In some embodiments, the first aging treatment temperature is 120-140° C.; and / or the first aging treatment time is 1-2 hours.

[0059] The first aging of the present invention adopts low-temperature pre-aging treatment to form a high-density GP zone in the high-strength and tough Al-V-Ti-Mn-Mg aluminum alloy, providing nucleation sites for the subsequent precipitation of strengthening phase grains.

[0060] In some embodiments, the heating rate of the heating is 5-10° C. / min; and / or the second aging treatment temperature is 300-330° C.; and / or the second aging treatment time is 2-4 hours.

[0061] The second aging of the present invention adopts high-temperature aging treatment to promote the uniform precipitation of Al3 (Sc, Zr, Er) nanophase grains in the high-strength and tough Al-V-Ti-Mn-Mg aluminum alloy, effectively improving the mechanical properties of the high-strength and tough Al-V-Ti-Mn-Mg aluminum alloy.

[0062] Due to the composition design of the present invention, elements such as V, Ti, Mn, and Mg are already supersaturated in the aluminum matrix and can be directly subjected to aging treatment, eliminating the solution quenching step in the traditional T6 heat treatment, thereby avoiding the problems of warping and high residual stress caused by high-strength and tough Al-V-Ti-Mn-Mg series aluminum alloy thin-walled parts due to high-temperature quenching, while simplifying the process and saving costs. In addition, the present invention adopts a solution-free treatment, which can suppress the segregation of impurity elements at the grain boundaries, thereby reducing the subsequent microporosity of the anodic oxide film, making the oxide film dense, and then uniformly colored. Compared with traditional aging treatment, the present invention promotes the uniform precipitation of Al3 (Sc, Zr, Er) nanophases through a low-temperature pre-aging treatment combined with a high-temperature aging treatment, thereby achieving a synergistic improvement in the strength and toughness of the high-strength and tough Al-V-Ti-Mn-Mg series aluminum alloy.

[0063] In some embodiments, the preparation method includes: performing anodizing after the aging treatment.

[0064] In some embodiments, the preparation method includes: performing a pretreatment before the anodizing; the pretreatment includes degreasing and pickling.

[0065] In some embodiments, the degreasing agent comprises an alkaline degreasing agent; and / or, the alkaline degreasing agent comprises: NaOH with a mass volume concentration of 30 to 50 g / L, and Na2CO3 with a mass volume concentration of 20 to 30 g / L; and / or, the degreasing temperature is 50 to 60°C; and / or, the degreasing time is 3 to 5 minutes.

[0066] Compared with traditional high-temperature and high-pressure degreasing processes, the alkaline degreasing process provided by the present invention only requires lower temperatures and shorter times to effectively remove surface oil stains and slight oxides from high-strength and tough Al-V-Ti-Mn-Mg aluminum alloys, thereby improving their surface quality and facilitating subsequent anodizing and coloring processes.

[0067] In some embodiments, the pickling solution contains HNO 3 with a volume fraction of 10 to 15%; and / or the pickling time is 0.5 to 1 min.

[0068] The present invention adopts acid washing after alkaline degreasing, which can effectively remove residual alkali solution on the surface of the aluminum alloy and activate the surface, which is beneficial to the subsequent anodizing and coloring processes.

[0069] In some embodiments, the temperature of the anodization is 18 to 22° C.; and / or the time of the anodization is 30 to 60 min; and / or the current density of the anodization is 1.0 to 1.5 A / dm 2 ; and / or, the voltage of the anodic oxidation is 12 to 18 V; and / or, the anodic oxidation uses direct current.

[0070] In some embodiments, the agitation method of the anodizing is air agitation or mechanical agitation. The present invention can effectively avoid problems such as ablation caused by local overheating and degradation of the oxide film layer quality by stirring during the anodizing process.

[0071] In some embodiments, the preparation method includes: after the anodizing, further performing coloring, and the colored electrolyte contains SnSO4 with a mass volume concentration of 10 to 15 g / L and NiSO4 with a mass volume concentration of 5 to 8 g / L.

[0072] In some embodiments, the coloring is performed using alternating current; and / or the current density of the alternating current is 0.2 to 0.5 A / dm 2 ; and / or, the voltage of the alternating current is 10 to 15 V; and / or, the coloring temperature is 20 to 25° C.; and / or, the coloring time is 2 to 5 min.

[0073] During the anodizing process, SnSO4 can make the aluminum alloy appear bronze-colored, and NiSO4 can make the aluminum alloy appear yellow, bronze, and black. The present invention optimizes the electrolytic coloring process by combining SnSO4 and NiSO4, so that the high-strength and toughness Al-V-Ti-Mn-Mg aluminum alloy oxide film can stably present richer colors. Compared with traditional electrolytic coloring, the color difference is significantly reduced, thereby preparing high-strength and toughness Al-V-Ti-Mn-Mg aluminum alloy with rich and uniform appearance, which can meet a variety of application scenarios, such as applications in consumer electronics, automobile manufacturing and other fields.

[0074] In some embodiments, the preparation method comprises: performing a sealing treatment after the coloring.

[0075] In some embodiments, the sealing treatment comprises hot water sealing; and / or the temperature of the hot water sealing is 80-95° C.; and / or the time of the hot water sealing is 20-30 minutes.

[0076] The present invention uses hot water sealing to make the aluminum oxide on the aluminum alloy react with water to generate boehmite AlO(OH), thereby sealing the pores of the oxide film and effectively improving the corrosion resistance and color stability of the high-strength and tough Al-V-Ti-Mn-Mg aluminum alloy.

[0077] The present application obtains high-toughness Al-V-Ti-Mn-Mg series aluminum alloy with uniform oxide film thickness, rich and uniform appearance color, and high strength, which meets various application scenarios; meanwhile, the present application shortens the overall oxidation and coloring process time and improves process efficiency. Further, the present application precisely controls the parameters of pretreatment-oxidation-coloring-closing each link by designing aluminum alloy composition, so that the prepared high-toughness Al-V-Ti-Mn-Mg series aluminum alloy has uniform oxide film thickness, thereby significantly improving the corrosion resistance of high-toughness Al-V-Ti-Mn-Mg series aluminum alloy and reducing coloring color difference.

[0078] The present application coordinates alloy composition design, preparation process, direct aging heat treatment, and subsequent anodic oxidation and coloring process, improves the strength and toughness of high-toughness Al-V-Ti-Mn-Mg series aluminum alloy, effectively avoids the problem of oxide film defects caused by excessive coarse second-phase grain of Mn and Mg elements, resulting in uneven local oxidation rate of anodic oxidation, thereby obtaining high-density and excellent performance oxide film after anodic oxidation, and preparing high-toughness aluminum alloy with excellent corrosion resistance and small coloring color difference; meanwhile, the high-toughness Al-V-Ti-Mn-Mg series aluminum alloy provided by the present application has low cost and strong composition-process adaptability, and has significant competitiveness in the fields of consumer electronics and automobile manufacturing.

[0079] Example 1

[0080] The aluminum alloy composition in Example 1 contains, by mass percentage: 0.5% V, 0.4% Ti, 0.8% Mn, 0.8% Mg, 0.3% Cr, 0.2% Sc, 0.1% Zr, and the balance of Al and unavoidable impurities.

[0081] Preparation of raw materials: according to the composition of the aluminum alloy, prepare the required pure Al, pure Mg, Al-10% V intermediate alloy, Al-5% Ti-B intermediate alloy, Al-10% Mn intermediate alloy, Al-10% Cr intermediate alloy, Al-2% Sc intermediate alloy, Al-10% Zr intermediate alloy, and Al-10% Er intermediate alloy; wherein, considering the burning loss of Mg element, the pure Mg is dosed at a burning loss rate of 15%.

[0082] Preheating: preheat the raw materials to 200℃ to sufficiently remove moisture in the raw materials.

[0083] Melting: put pure Al into a 760℃ resistance furnace and melt to obtain a first melt;

[0084] After cooling the first melt to 750℃, sequentially add Al-10% V intermediate alloy, Al-10% Mn intermediate alloy, and Al-10% Cr intermediate alloy, heat for 20-30 min to melt to obtain a second melt;

[0085] Al-5% Ti-B master alloy, Al-2% Sc master alloy, Al-10% Zr master alloy, and Al-10% Er master alloy are sequentially added, kept warm for 30 to 40 minutes and melted to obtain a third melt;

[0086] After the third melt is cooled to 700° C., pure Mg is pressed into the third melt below its liquid level using a low-carbon steel bell jar and melted by keeping the temperature for 15 to 20 minutes to obtain a fourth melt.

[0087] Refining and degassing: After deslagging with a low-carbon steel deslagging spoon, the fourth melt is heated to 750° C., and then refined and degassed with high-purity argon for 10 to 15 minutes, and then allowed to stand for 15 to 20 minutes to obtain a metal melt after deslagging; during the refining and degassing process, the fourth melt is stirred up and down in an orderly manner to make its composition uniform.

[0088] Squeeze casting: The metal melt is cooled to 730°C, and the metal mold is preheated to 250°C. Then, under the condition of 100 MPa, the metal melt is poured into the preheated metal mold, and then extruded to obtain an aluminum alloy casting.

[0089] Aging treatment: placing the aluminum alloy casting in a box-type aging furnace for aging treatment to obtain an aluminum alloy; wherein the first aging temperature is 140°C and the time is 1.5 hours, and then the temperature is increased to 320°C at 10°C / min, and the second aging treatment is performed for 3 hours.

[0090] Anodizing and coloring the aluminum alloy to obtain an aluminum alloy product; wherein the anodizing and coloring comprises the following steps:

[0091] Use a degreasing agent containing 50g / L NaOH and 30g / L Na2CO3 at 60℃ for 5min;

[0092] Use 15% volume fraction of HNO3 and pickle at room temperature for 30s;

[0093] The volume fraction of H2SO4 was 20%, and the current density was 1.5A / dm 2 , voltage of 18V DC, anodic oxidation for 60min at 22℃ and compressed air stirring;

[0094] A metal salt electrolyte containing 15g / L SnSo4 and 8g / L NiSo4 was used, and the current density was 0.5A / dm 2 , electrolytic coloring at 15V AC for 5min at 20℃;

[0095] Hot water sealing was performed with pure water at 95°C for 30 minutes.

[0096] Example 2

[0097] The difference between Example 2 and Example 1 is that:

[0098] The aluminum alloy composition in Example 2 comprises, by mass percentage, 0.4% V, 0.5% Ti, 0.6% Mn, 0.5% Mg, 0.2% Cr, 0.1% Sc, 0.1% Zr, and 0.1% Er, with the remainder being Al and unavoidable impurities.

[0099] The second melt is heated to 760°C, and Al-5%Ti-B master alloy, Al-2%Sc master alloy, Al-10%Zr master alloy, and Al-10%Er master alloy are added in sequence, and the mixture is kept at this temperature for 35 to 45 minutes to melt.

[0100] The refining and degassing time is 15 to 20 minutes;

[0101] The pressure of squeeze casting is 50MPa;

[0102] In the aging treatment, the first aging treatment temperature is 130℃, the time is 2h, the heating rate is 8℃ / min, and the second aging treatment temperature is 330℃, the time is 2h;

[0103] Degreasing agent containing 40g / L NaOH and 25g / L Na2CO3 was used for degreasing at 50℃;

[0104] The pickling time is 40s;

[0105] At a current density of 1.2 A / dm 2 , voltage 15V, 20℃, anodic oxidation for 60min under mechanical stirring conditions;

[0106] A metal salt electrolyte containing 12g / L SnSO4 and 5g / L NiSO4 was used at a current density of 0.4A / dm 2 , electrolytic coloring under the condition of voltage of 12V;

[0107] Hot water sealing was performed with pure water at 90°C for 25 min;

[0108] The remaining operations refer to Example 1.

[0109] Example 3

[0110] The difference between Example 3 and Example 1 is that:

[0111] Measured by mass percentage, the aluminum alloy composition in Example 3 includes: 0.35% V, 0.35% Ti, 0.4% Mn, 0.6% Mg, 0.3% Cr, 0.1% Zr, 0.2% Er, and the balance is Al and unavoidable impurities.

[0112] The second melt is heated to 760°C, and Al-5%Ti-B master alloy, Al-10%Zr master alloy, and Al-10%Er master alloy are added in sequence, and the mixture is kept at this temperature for 25 to 35 minutes to melt.

[0113] The pressure of squeeze casting is 50MPa;

[0114] In the aging treatment, the first aging treatment temperature is 120℃, the time is 2h, the heating rate is 5℃ / min, and the second aging treatment temperature is 310℃, the time is 2h;

[0115] Use a degreasing agent containing 30g / L NaOH and 20g / L Na2CO3 at 50℃ for 4min;

[0116] The pickling time is 40s;

[0117] Using H2SO4 with a volume fraction of 15%, at a current density of 1.1A / dm 2 , voltage 13V, 18℃, anodic oxidation for 40min under mechanical stirring conditions;

[0118] A metal salt electrolyte containing 10g / L SnSo4 and 5g / L NiSO4 was used at a current density of 0.3A / dm 2 , electrolytic coloring for 3 minutes at a voltage of 15V and a temperature of 22℃;

[0119] Hot water sealing was performed with pure water at 80°C for 20 min;

[0120] The remaining operations refer to Example 1.

[0121] Example 4

[0122] The difference between Example 4 and Example 1 is that:

[0123] Measured by mass percentage, the aluminum alloy composition in Example 4 includes: 0.3% V, 0.3% Ti, 0.8% Mn, 0.8% Mg, 0.3% Cr, 0.15% Zr, 0.15% Er, and the balance is Al and unavoidable impurities.

[0124] The second melt is heated to 760°C, and Al-5%Ti-B master alloy, Al-10%Zr master alloy, and Al-10%Er master alloy are added in sequence, and then kept at this temperature for 20 to 30 minutes to melt.

[0125] In the aging treatment, the first aging treatment temperature is 120 ° C, the time is 2 h, and the heating rate is 8 ° C / min;

[0126] Use a degreasing agent containing 30g / L NaOH and 20g / L Na2CO3 at 50℃ for 4min;

[0127] The pickling time is 40s;

[0128] Using H2SO4 with a volume fraction of 15%, at a current density of 1.1A / dm 2 , voltage 13V, 18℃, anodic oxidation for 40min under mechanical stirring conditions;

[0129] A metal salt electrolyte containing 10g / L SnSO4, 5g / L NiSO4, and 25g / L boric acid H3Bo3 was used at a current density of 0.4A / dm 2 , electrolytic coloring at 22℃ for 3min;

[0130] Hot water sealing was performed with pure water at 80°C for 20 min;

[0131] The remaining operations refer to Example 1.

[0132] Comparative Example 1

[0133] The difference between Comparative Example 1 and Example 1 is:

[0134] In terms of mass percentage, the aluminum alloy composition in Comparative Example 1 includes: 1.5% Mn, 1.5% Mg, 0.2% Sc, 0.1% Zr, and the balance is Al and unavoidable impurities; the remaining operations are referenced to Example 1.

[0135] The aluminum alloy product prepared in Comparative Example 1 had the film layer peeled off during the cross-cut test.

[0136] Comparative Example 2

[0137] The difference between Comparative Example 2 and Example 1 is:

[0138] In terms of mass percentage, the aluminum alloy composition in Comparative Example 2 includes: 0.5% V, 0.4% Ti, 0.9% Mn, 0.8% Mg, 0.3% Cr, and the balance is Al and unavoidable impurities; the remaining operations refer to Example 1.

[0139] Comparative Example 3

[0140] The difference between Comparative Example 3 and Example 1 is:

[0141] The aluminum alloy composition in Comparative Example 3 comprises, by mass percentage, 0.4% V, 0.5% Ti, 0.6% Mn, 0.5% Mg, 0.2% Cr, 0.1% Sc, 0.1% Zr, and 0.1% Er, with the balance being Al and unavoidable impurities.

[0142] The second melt is heated to 760°C, and Al-5%Ti-B master alloy, Al-2%Sc master alloy, Al-10%Zr master alloy, and Al-10%Er master alloy are added in sequence, and the mixture is kept at this temperature for 35 to 45 minutes to melt.

[0143] The refining and degassing time is 15 to 20 minutes;

[0144] Instead of using squeeze casting, gravity casting is used; the molten metal is poured directly into the metal mold and solidified naturally under the action of gravity;

[0145] In the aging treatment, the first aging treatment temperature is 130℃, the time is 2h, the heating rate is 8℃ / min, and the second aging treatment temperature is 330℃, the time is 2h;

[0146] Degreasing agent containing 40g / L NaOH and 25g / L Na2CO3 was used for degreasing at 50℃;

[0147] The pickling time is 40s;

[0148] At a current density of 1.2 A / dm 2 , voltage 15V, 20℃, anodic oxidation for 60min under mechanical stirring conditions;

[0149] A metal salt electrolyte containing 12g / L SnSO4 and 5g / L NiSO4 was used at a current density of 0.4A / dm 2 , electrolytic coloring under the condition of voltage of 12V;

[0150] Hot water sealing was performed with pure water at 90°C for 25 min;

[0151] The remaining operations refer to Example 1.

[0152] The aluminum alloy prepared in Comparative Example 3 had defects on its surface. During the anodization process, the electrolyte penetrated into the defects, forming corrosion pits with a diameter greater than 50 μm.

[0153] Comparative Example 4

[0154] The difference between Comparative Example 4 and Example 1 is:

[0155] The aluminum alloy composition in Comparative Example 4 contains, by mass percent: 0.35% V, 0.35% Ti, 0.4% Mn, 0.6% Mg, 0.3% Cr, 0.1% Zr, 0.2% Er, with the balance being Al and inevitable impurities.

[0156] The second melt was heated to 760°C, and then Al-5% Ti-B master alloy, Al-10% Zr master alloy, and Al-10% Er master alloy were added successively, and the melt was maintained for 25-35 min;

[0157] The pressure for the squeeze casting was 50 MPa;

[0158] In the aging treatment, the first aging treatment was not performed, and the second aging treatment was performed at 310°C for 2 h;

[0159] Degreasing was performed at 50°C for 4 min using a degreasing agent containing 30 g / L NaOH and 20 g / L Na2CO3;

[0160] The pickling time was 40 s;

[0161] Anodization was performed at 18°C under the conditions of a current density of 1.1 A / dm2, a voltage of 13 V, and mechanical stirring for 40 min using 15% H2SO4 by volume; 2

[0162] Electrolytic coloring was performed at 22°C under the conditions of a current density of 0.3 A / dm2 and a voltage of 15 V for 3 min using a metal salt electrolyte containing 10 g / L SnSO4 and 5 g / L NiSO4; 2

[0163] Hot water sealing was performed at 80°C for 20 min using pure water;

[0164] The remaining operations were performed according to Example 1.

[0165] Comparative Example 5

[0166] Comparative Example 5 differs from Example 1 in that:

[0167] The aluminum alloy composition in Comparative Example 5 contains, by mass percent: 0.3% V, 0.3% Ti, 0.8% Mn, 0.8% Mg, 0.3% Cr, 0.15% Zr, 0.15% Er, with the balance being Al and inevitable impurities.

[0168] The second melt was heated to 760°C, and then Al-5% Ti-B master alloy, Al-10% Zr master alloy, and Al-10% Er master alloy were added successively, and the melt was maintained for 20-30 min;

[0169] ​​In the aging treatment, the temperature of the first aging treatment is 120℃, the time is 2h, and the heating rate is 8℃ / min;

[0170] Without degreasing and pickling;

[0171] Using 15% H2SO4 by volume fraction, anodizing for 40min under the conditions of current density of 1.1A / dm 2 , voltage of 13V, 18℃, mechanical stirring;

[0172] Using metal salt electrolyte containing 10g / L SnSO4, 5g / L NiSO4, 25g / L boric acid H3BO3, electrolytic coloring for 3min under the conditions of current density of 0.4A / dm 2 , 22℃;

[0173] Sealing with pure water at 80℃ for 20min;

[0174] The rest of the operation refers to Example 1.

[0175] The aluminum alloy prepared in Comparative Example 5 has a local non-growth phenomenon of the oxide film during anodic oxidation, and there are white spot defects with a diameter of 1-2mm.

[0176] Performance test of Examples 1-4 and Comparative Examples 1-5

[0177] 1. Hardness: measured by microhardness tester FM700.

[0178] 2. Tensile strength, yield strength, elongation: tested according to GB / T 228.1-2021.

[0179] 3. Forming quality: detected by X-ray and counted the defects such as pores or cold shuts of the aluminum alloy sample.

[0180] 4. Oxide film thickness uniformity: the oxide film thickness data of the aluminum alloy sample at different positions were detected by X-ray thickness gauge, and the change value of the obtained data was calculated as the thickness uniformity of the oxide film.

[0181] 5. Color difference ΔE of coloring: detected according to GB / T 12967.6-2022, and compared with RAL standard.

[0182] 6. Salt spray test: tested according to ISO 9227:2022 neutral salt spray test (NSS) standard.

[0183] According to the above method, the hardness, tensile strength, yield strength and elongation of the aluminum alloys prepared in Examples 1 to 4 and Comparative Examples 1 to 5 were tested; the forming quality, oxide film thickness uniformity, color difference ΔE, and salt spray life of the aluminum alloy products prepared in Examples 1 to 4 and Comparative Examples 1 to 5 were tested; the composition and performance test results of the aluminum alloys of Examples 1 to 4 and Comparative Examples 1 to 5 are shown in Table 1.

[0184] Table 1. Aluminum alloy compositions and performance test results of Examples 1 to 4 and Comparative Examples 1 to 5

[0185]

[0186]

[0187] By comparing Table 1 and reference Figure 1 and Figure 2 It can be seen that the aluminum alloy product prepared in Example 1 not only has high strength and toughness, but also has excellent corrosion resistance and a coloring effect with small color difference. This is because the present invention achieves the effect of refining grains and inhibiting component segregation while maintaining the high strength and toughness of the Al-V-Ti-Mn-Mg series aluminum alloy by reasonably matching the components of the high-strength and tough Al-V-Ti-Mn-Mg series aluminum alloy, thereby reducing the coarse second phase grains in the high-strength and tough Al-V-Ti-Mn-Mg series aluminum alloy, thereby effectively reducing the generation of surface defects such as micropores and cracks, and at the same time avoiding the uneven local oxidation rate of anodizing caused by coarse second phase grains, reducing the porosity of the high-strength and tough Al-V-Ti-Mn-Mg series aluminum alloy, and then making the high-strength and tough Al-V-Ti-Mn-Mg series aluminum alloy obtain a highly dense and uniform oxide film after anodizing, significantly improving the corrosion resistance of the high-strength and tough Al-V-Ti-Mn-Mg series aluminum alloy and reducing color difference.

[0188] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form or substance. It should be pointed out that ordinary technicians in this technical field can make several improvements and supplements without departing from the method of the present invention. These improvements and supplements should also be regarded as the scope of protection of the present invention. Any equivalent changes, modifications and evolutions made by technicians familiar with this profession without departing from the spirit and scope of the present invention by using the technical content disclosed above are all equivalent embodiments of the present invention; at the same time, any equivalent changes, modifications and evolutions made to the above embodiments based on the essential technology of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A high-strength and tough Al-V-Ti-Mn-Mg aluminum alloy, characterized in that: Measured by mass percentage, the components of the high-strength and toughness Al-V-Ti-Mn-Mg aluminum alloy include: 0.05-0.5% V, 0.05-0.5% Ti, 0.4-1.2% Mn, 0.3-1.2% Mg, 0.1-0.3% Cr, unavoidable impurity elements ≤0.15%, and at least one of Sc, Zr, and Er, with Sc≤0.2%, Zr≤0.2%, Er≤0.2%, and the balance is A1.

2. The high-strength and tough Al-V-Ti-Mn-Mg aluminum alloy according to claim 1, characterized in that: Measured by mass percentage, the components of the high-strength and toughness Al-V-Ti-Mn-Mg aluminum alloy include: 0.1-0.5% V, 0.3-0.5% Ti, 0.4-0.8% Mn, 0.3-0.8% Mg, 0.1-0.3% Cr, unavoidable impurity elements ≤0.15%, and at least one of Sc, Zr, and Er, with Sc≤0.2%, Zr≤0.2%, Er≤0.2%, and the balance is A1.

3. The high strength and toughness Al-V-Ti-Mn-Mg aluminum alloy according to claim 1 or 2, characterized in that: In the high-strength and tough Al-V-Ti-Mn-Mg aluminum alloy, the sum of the mass percentages of Sc, Zr and Er is less than or equal to 0.3%.

4. A method for preparing a high-strength and tough Al-V-Ti-Mn-Mg aluminum alloy according to any one of claims 1 to 3, characterized in that: The preparation method comprises the following steps: Prepare raw materials according to the composition of the high-strength and toughness Al-V-Ti-Mn-Mg aluminum alloy; Preheating, melting, refining and degassing the raw materials to obtain a metal melt; The metal melt is subjected to extrusion casting and aging treatment to obtain the high-strength and toughness Al-V-Ti-Mn-Mg aluminum alloy, and the aging treatment includes: heating after a first aging treatment and performing a second aging treatment.

5. The method for preparing a high-strength and tough Al-V-Ti-Mn-Mg aluminum alloy according to claim 4, wherein: In the squeeze casting, the temperature of the metal melt is 730-740° C.; and / or The squeeze casting pressure is 50-100 MPa; and / or, The holding time of the squeeze casting is 15 to 30 seconds.

6. The method for preparing a high-strength and tough Al-V-Ti-Mn-Mg aluminum alloy according to claim 4, wherein: The first aging treatment temperature is 120-140° C.; and / or, The first aging treatment time is 1 to 2 hours; and / or, The heating rate of the heating is 5 to 10°C / min; and / or, The second aging treatment temperature is 300-330°C; and / or, The second aging treatment time is 2 to 4 hours.

7. The method for preparing a high-strength and tough Al-V-Ti-Mn-Mg aluminum alloy according to claim 4, wherein: The preparation method comprises: after the aging treatment, further performing anodizing, the anodizing temperature is 18 to 22° C., and the anodizing time is 30 to 60 minutes.

8. The method for preparing a high-strength and tough Al-V-Ti-Mn-Mg aluminum alloy according to claim 7, characterized in that: The current density of the anodic oxidation is 1.0 to 1.5 A / dm 2 and / or, The voltage of the anodic oxidation is 12 to 18V.

9. The method for preparing a high-strength and tough Al-V-Ti-Mn-Mg aluminum alloy according to claim 7, wherein: The preparation method comprises: coloring after the anodizing, wherein the colored electrolyte contains SnSO4 with a mass volume concentration of 10 to 15 g / L and NiSO4 with a mass volume concentration of 5 to 8 g / L.

10. The method for preparing a high-strength and tough Al-V-Ti-Mn-Mg aluminum alloy according to claim 9, characterized in that: The coloring adopts alternating current; and / or, The current density of the alternating current is 0.2 to 0.5 A / dm 2 and / or, The voltage of the alternating current is 10-15V; and / or, The coloring temperature is 20-25°C; and / or, The coloring time is 2 to 5 minutes.

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