Aluminum alloy material and preparation method thereof and aluminum alloy structural part

Abstract

The present invention discloses an aluminum alloy material, a preparation method thereof and an aluminum alloy structural part. The aluminum alloy material comprises: an aluminum alloy substrate; a protective layer, the protective layer is arranged on the surface of the aluminum alloy substrate, the protective layer comprises a plurality of aluminum oxide layers and metal M oxide layers which are alternately stacked in sequence, and the metal M is selected from at least one of titanium, niobium, zirconium and tantalum; wherein the surface of the aluminum alloy substrate is in contact with the aluminum oxide layer, and the outermost layer of the aluminum alloy material is the oxide layer of the metal M. The present invention significantly improves the surface density and salt corrosion resistance of the aluminum alloy material, and also significantly improves the wear resistance and hardness of the aluminum alloy material, and the protective layer of the present invention has good adhesion to the aluminum alloy substrate.

Description

Technical Field

[0001] The present invention belongs to the technical field of metal materials, and in particular relates to an aluminum alloy material and a preparation method thereof, and an aluminum alloy structural part. Background Art

[0002] Metal materials have always played a vital role in the development of human science and technology. It is no exaggeration to say that the application of metal materials and technological progress have directly promoted the development of human society. With the development of human science and technology, the performance requirements for metal materials are getting higher and higher. Among them, the most common problem is the corrosion of metals, which directly affects the service life of workpieces and even causes many major losses. According to statistics, no less than 1 / 10 of metal materials are forced to be scrapped due to corrosion problems every year. Aluminum alloy, as an alloy material with low density, high strength, good conductivity and high plasticity, has received widespread attention and application in recent years. Aluminum is a metal with strong chemical activity. It is very easy to react with oxygen in the air to form a layer of oxide film to prevent further oxidation of the metal aluminum inside. However, this oxide film cannot resist the penetration corrosion of chloride ions in salt spray, which seriously limits the application of aluminum alloy in the fields of ships, electronic instruments, chemical industry, etc.

[0003] At present, the anti-corrosion layer is widely prepared by chemical treatment of aluminum alloy surface, which is costly and polluting, and is not conducive to industrial promotion. Or other alloy materials are directly sputtered on the aluminum alloy surface. The salt corrosion-resistant layer prepared by this method has poor adhesion and has problems such as excessive stress, which leads to cracking of the edge and micro-crack corrosion, which leads to film shedding. Summary of the invention

[0004] The present invention aims to solve one of the technical problems in the related art to at least a certain extent. To this end, one object of the present invention is to provide an aluminum alloy material and a preparation method thereof and an aluminum alloy structural part. The present invention significantly improves the surface density and salt corrosion resistance of the aluminum alloy material, and also significantly improves the wear resistance and hardness of the aluminum alloy material, and the protective layer of the present invention has good adhesion to the aluminum alloy substrate.

[0005] In one aspect of the present invention, the present invention provides an aluminum alloy material. According to an embodiment of the present invention, the aluminum alloy material comprises:

[0006] Aluminum alloy substrate;

[0007] A protective layer, the protective layer is arranged on the surface of the aluminum alloy substrate, the protective layer comprises a plurality of aluminum oxide layers and metal M oxide layers alternately stacked in sequence, the metal M is selected from at least one of titanium, niobium, zirconium and tantalum;

[0008] Wherein, the surface of the aluminum alloy substrate is in contact with the aluminum oxide layer, and the oxide layer of the metal M is arranged on the outermost layer of the aluminum alloy material.

[0009] According to the aluminum alloy material of the embodiment of the present invention, by stacking an oxide layer of metal M with good ductility on the surface of the aluminum oxide layer, the oxide of metal M fills the microporous structure on the surface of the aluminum oxide layer, thereby significantly improving the surface density and salt corrosion resistance of the protective layer. The stacked structure uses the aluminum oxide layer as the base layer to improve the adhesion of the protective layer to the aluminum alloy substrate; the oxide of metal M with good surface density is used as the outermost layer to improve the overall corrosion resistance of the protective layer. At the same time, the wear resistance and hardness of the aluminum alloy material are significantly improved by the structure in which the aluminum oxide layer and the oxide layer of metal M are alternately stacked in sequence.

[0010] In addition, the aluminum alloy material according to the above embodiment of the present invention may also have the following additional technical features:

[0011] In some embodiments of the present invention, the thickness of a single layer of the aluminum oxide layer is no more than 50 nm.

[0012] In some embodiments of the present invention, the thickness of a single layer of the oxide layer of the metal M is no more than 50 nm.

[0013] In some embodiments of the present invention, the difference between the thickness of the single-layer aluminum oxide layer and the thickness of the single-layer oxide layer of the metal M is no more than 30 nm.

[0014] In some embodiments of the present invention, the ratio of the thickness of the single-layer aluminum oxide layer to the thickness of the single-layer oxide layer of the metal M is (3:1) to (1:3), preferably 1:1.

[0015] In some embodiments of the present invention, the thickness of a single layer of the aluminum oxide layer is 10-20 nm.

[0016] In some embodiments of the present invention, the thickness of a single layer of the oxide layer of the metal M is 10-20 nm.

[0017] In some embodiments of the present invention, the total thickness of the protective layer is 350-800 nm.

[0018] In some embodiments of the present invention, the total number of the aluminum oxide layers and the oxide layers of the metal M that are alternately stacked in sequence is 20 to 40 layers.

[0019] In some embodiments of the present invention, the hardness of the aluminum alloy material is 15-25 GPa.

[0020] In another aspect of the present invention, the present invention provides a method for preparing the above-mentioned aluminum alloy material. According to an embodiment of the present invention, the method comprises:

[0021] An electron beam coating method is used to form a plurality of aluminum oxide layers and metal M oxide layers which are alternately stacked in sequence on the surface of the aluminum alloy substrate.

[0022] According to the method for preparing the above-mentioned aluminum alloy material in an embodiment of the present invention, a plurality of aluminum oxide layers and metal M oxide layers that are alternately stacked in sequence are formed on the surface of the aluminum alloy substrate by an electron beam plating method, thereby improving the edge coverage and overall uniformity of the aluminum alloy substrate, and further improving the overall salt corrosion resistance of the aluminum alloy material.

[0023] In addition, the method according to the above embodiment of the present invention may also have the following additional technical features:

[0024] In some embodiments of the present invention, the evaporation rate of the aluminum oxide layer is The evaporation rate of the oxide layer of the metal M is

[0025] In a third aspect of the present invention, the present invention provides an aluminum alloy structural part. According to an embodiment of the present invention, the aluminum alloy structural part has the aluminum alloy material described in the above embodiment. Therefore, the aluminum alloy structural part has all the advantages of the aluminum alloy material in the above embodiment, specifically, the surface density, salt corrosion resistance, wear resistance and hardness of the aluminum alloy structural part are significantly improved.

[0026] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0028] Figure 1 A schematic diagram of the structure of an aluminum alloy material according to an embodiment of the present invention;

[0029] Figure 2 It is a schematic diagram of the results of the aluminum alloy materials of Examples 1-2 of the present invention and Comparative Example 1 after 96 hours of salt spray corrosion.

[0030] The accompanying drawings are labeled: 100 - aluminum alloy substrate, 200 - protective layer, 201 - aluminum oxide layer, 202 - oxide layer of metal M. DETAILED DESCRIPTION

[0031] Embodiments of the present invention are described in detail below, examples of the above embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0032] In one aspect of the present invention, the present invention provides an aluminum alloy material. Figure 1 , the aluminum alloy material comprises: an aluminum alloy substrate 100; a protective layer 200, the protective layer 200 is arranged on the surface of the aluminum alloy substrate 100, the protective layer 200 comprises a plurality of aluminum oxide layers 201 and metal M oxide layers 202 which are alternately stacked in sequence, and the metal M is selected from at least one of titanium, niobium, zirconium and tantalum; wherein the surface of the aluminum alloy substrate 100 is in contact with the aluminum oxide layer 201, that is, the aluminum oxide layer 201 is in close contact with the surface of the aluminum alloy substrate 100, and the oxide layer 202 of the metal M is arranged on the outermost layer of the aluminum alloy material. The present invention significantly improves the surface density and salt corrosion resistance of the aluminum alloy material, and also significantly improves the wear resistance and hardness of the aluminum alloy material, and the protective layer 200 of the present invention has good adhesion to the aluminum alloy substrate 100. The aluminum alloy material according to the embodiment of the present invention is further described in detail below.

[0033] Specifically, the aluminum oxide layer, as a protective layer of the aluminum alloy substrate, has good adhesion to the aluminum alloy substrate and has a certain effect of preventing oxidation, but this oxide film cannot resist the penetration corrosion of chloride ions in salt spray, which seriously limits the application of aluminum alloy in the fields of ships, electronic instruments, chemical industry, etc. If other alloy materials are directly sputtered on the surface of the aluminum alloy, the salt corrosion-resistant layer prepared by this method has poor adhesion and there are problems such as excessive stress causing the edge to crack and micro-crack corrosion, which in turn causes the film to fall off. In view of this, the present invention stacks an oxide layer of metal M with good ductility on the surface of the aluminum oxide layer, so that the oxide of metal M fills the microporous structure on the surface of the aluminum oxide layer, and the oxide of metal M plays a role in sealing the aluminum oxide material, hindering the penetration corrosion of chloride ions, thereby significantly improving the surface density and salt corrosion resistance of the protective layer. The stacked structure uses an aluminum oxide layer as a base layer, and the aluminum oxide layer can be well combined with the aluminum alloy surface, which improves the adhesion of the protective layer to the aluminum alloy substrate; the oxide of metal M with good surface density is used as the outermost layer, which improves the overall corrosion resistance of the protective layer. At the same time, the structure in which the aluminum oxide layer and the oxide layer of the metal M are alternately stacked in sequence significantly improves the wear resistance and hardness of the aluminum alloy material.

[0034] Since the single-layer metal M oxide layer has a large internal stress that is easy to expand outward as the thickness increases, stress release is easy to occur at the edge of the film layer, resulting in microcracks, and then micro-crack corrosion, which is unacceptable for the corrosion-resistant protective layer. Therefore, the present invention innovatively proposes an overlapping structure of an aluminum oxide layer and a metal M oxide layer as an aluminum alloy protective layer, thereby overcoming the stress release problem caused by the excessive thickness of the single-layer metal M oxide layer. In addition, this overlapping structure of an aluminum oxide layer and a metal M oxide layer also significantly improves the wear resistance and hardness of the aluminum alloy material. The inventor found that, under the premise that the total thickness of the protective layer is the same, the more total layers of the aluminum oxide layer and the metal M oxide layer, the greater the hardness of the protective layer and the better the wear resistance of the protective layer.

[0035] In the embodiment of the present invention, the oxide layer of metal M is selected from at least one of titanium oxide layer, niobium oxide layer, zirconium oxide layer and tantalum oxide layer, and the surface density of the above-mentioned oxide layer is good, thereby significantly improving the salt corrosion resistance of the protective layer. At the same time, the ductility of the above-mentioned oxide layer is good, so that the oxide of metal M fills the microporous structure on the surface of the aluminum oxide layer, which not only improves the surface density and salt corrosion resistance of the aluminum oxide layer, but also makes the aluminum oxide layer and the oxide layer of metal M have good adhesion.

[0036] As mentioned above, since the single-layer metal M oxide layer has a larger internal stress as the thickness increases, in order to avoid the problem of micro cracks caused by excessive internal stress, the thickness of the single-layer metal M oxide layer should not be too large. According to some specific embodiments of the present invention, the thickness of the single-layer metal M oxide layer is not greater than 50nm. At the same time, if the thickness of the single-layer metal M oxide layer is too large, then under the premise that the total thickness of the protective layer is the same, the total number of aluminum oxide layers and metal M oxide layers will inevitably decrease, and the hardness and wear resistance of the protective layer will inevitably decrease. In other words, if the thickness of the single-layer metal M oxide layer is too large, it is not conducive to improving the hardness and wear resistance of the protective layer.

[0037] According to some further specific embodiments of the present invention, the thickness of the single-layer aluminum oxide layer is not greater than 50 nm. Therefore, limiting the thickness of the single-layer aluminum oxide layer within the above range is conducive to improving the hardness and wear resistance of the protective layer. It can be understood that if the thickness of the single-layer aluminum oxide layer is too large, then under the premise that the total thickness of the protective layer is the same, the total number of aluminum oxide layers and metal M oxide layers will inevitably decrease, and the hardness and wear resistance of the protective layer will inevitably decrease.

[0038] According to some specific embodiments of the present invention, the difference between the thickness of the single-layer aluminum oxide layer and the thickness of the single-layer metal M oxide layer is not greater than 30 nm, which is further conducive to improving the hardness and wear resistance of the protective layer. The inventors have found that, under the premise that the total thickness of the protective layer is the same, the closer the thickness of the aluminum oxide layer and the metal M oxide layer is, the more conducive it is to improving the hardness and wear resistance of the protective layer.

[0039] According to some other specific embodiments of the present invention, the ratio of the thickness of the single-layer aluminum oxide layer to the thickness of the single-layer oxide layer of the metal M is (3:1) to (1:3), which is further beneficial to improving the hardness and wear resistance of the protective layer, preferably 1:1.

[0040] Taking into account factors such as production efficiency and mass production, according to some specific embodiments of the present invention, the thickness of the single-layer aluminum oxide layer is 10 to 20 nm, and the thickness of the single-layer metal M oxide layer is 10 to 20 nm. The thickness of the single-layer aluminum oxide layer and the metal M oxide layer is limited to the above ranges, which fully ensures the improvement of the surface density, salt corrosion resistance, hardness and wear resistance of the protective layer, and fully considers factors such as production efficiency and mass production. It can be understood that although the thinner the thickness of the single-layer aluminum oxide layer and the metal M oxide layer, the more conducive it is to improve the hardness and wear resistance of the protective layer, the production efficiency of the aluminum alloy material is greatly reduced, and its mass production is significantly reduced. Preferably, the total number of layers of the above-mentioned aluminum oxide layer and the above-mentioned metal M oxide layer, which are alternately stacked in sequence, is 20 to 40 layers.

[0041] Under the laminated structure of the present invention, when the total thickness of the protective layer is 350-800nm, the hardness of the surface of the aluminum alloy material can reach 15-25GPa. Compared with the traditional PVD Cr-plating process for protecting aluminum alloy, which requires a 2μm or even thicker protective film, the thickness of the protective film of the present invention is only a few hundred nanometers, which is much lower than the material consumption of traditional PVD, and the protection at the corners of the substrate is much better than the traditional process.

[0042] Specifically, the aluminum alloy matrix can be a cast aluminum alloy, a rolled aluminum alloy, or an extruded aluminum alloy, etc. The above materials have a wide range of sources, low cost, high structural strength, and good processability.

[0043] In another aspect of the present invention, the present invention provides a method for preparing the above-mentioned aluminum alloy material. According to an embodiment of the present invention, the above-mentioned method comprises:

[0044] The electron beam coating method is used to form a plurality of aluminum oxide layers and metal M oxide layers that are alternately stacked in sequence on the surface of the aluminum alloy substrate. Thus, by using the electron beam coating method to form a plurality of aluminum oxide layers and metal M oxide layers that are alternately stacked in sequence on the surface of the aluminum alloy substrate, the edge coverage and overall uniformity of the aluminum alloy substrate are improved, and the overall salt corrosion resistance of the aluminum alloy material is further improved.

[0045] Specifically, for aluminum alloy substrates with relatively sharp edges, coating on the sharp aluminum alloy substrate surface will cause the problem of sharp corner stress release, which makes the edge easy to crack, and the anodic process used in the prior art for surface strengthening process cannot achieve good edge coverage, which makes the edge easy to crack. The present invention uses electron beam coating method to achieve good coverage in the sharp corner area of ​​the aluminum alloy substrate edge, thereby improving the edge coverage and overall uniformity of the aluminum alloy substrate, and further improving the overall salt corrosion resistance of the aluminum alloy material.

[0046] Furthermore, the above method specifically comprises the following steps:

[0047] (1) placing the aluminum alloy substrate on the fixture of the coating machine, evacuating the substrate, and setting a suitable substrate temperature to reduce outgassing of the aluminum alloy substrate;

[0048] (2) When the vacuum degree of the coating chamber reaches the required level, turn on the ion source to perform ion cleaning on the surface of the substrate;

[0049] (3) Turn on the electron gun to heat and evaporate the aluminum oxide. The evaporation thickness can be set according to actual needs;

[0050] (4) Turn off the electron gun, rotate the crucible plate to the position of the metal M oxide, turn on the electron gun to heat and evaporate the metal M oxide, and the evaporation thickness can be set according to actual needs to complete a single cycle of the overlapping structure;

[0051] (5) Repeat the above steps (3)-(4) for N cycles to complete the evaporation of the protective film;

[0052] (6) After the coating is completed, turn off the power of the electron gun, turn off the power of the ion source, stop the rotation of the turntable, wait for the workpiece to cool down, start the freezer to defrost, and finally inflate it and restore it to atmospheric pressure before taking it out.

[0053] Furthermore, the evaporation rate of the aluminum oxide layer is The evaporation rate of the oxide layer of the metal M is Therefore, the evaporation rates of the aluminum oxide layer and the metal M oxide layer are limited within the above range, and the surface density of the aluminum oxide layer and the metal M oxide layer is further ensured.

[0054] In the third aspect of the present invention, the present invention provides an aluminum alloy structural part. According to an embodiment of the present invention, the aluminum alloy structural part has the aluminum alloy material described in the above embodiment. Therefore, the above aluminum alloy structural part has all the advantages of the aluminum alloy material described in the above embodiment, and significantly improves the surface density, salt corrosion resistance, wear resistance and hardness of the aluminum alloy structural part. Specifically, the above aluminum alloy structural part can be used in the fields of ships, electronic instruments, chemical industry, etc.

[0055] The embodiments of the present invention are described in detail below. It should be noted that the embodiments described below are exemplary and are only used to explain the present invention, and cannot be interpreted as limiting the present invention. In addition, if not explicitly stated, all reagents used in the following embodiments are commercially available, or can be synthesized according to this article or known methods, and the reaction conditions not listed are also easily available to those skilled in the art.

[0056] Example 1

[0057] This embodiment provides a method for preparing an aluminum alloy material, wherein the thickness of a single aluminum oxide layer in a single cycle is 10 nm, and the thickness of a single titanium dioxide layer is 10 nm, and 20 cycles are repeated, i.e., the protective film as a whole has a 40-layer structure with a total thickness of 400 nm. The method comprises the following steps:

[0058] a. Place the aluminum alloy substrate on the fixture of the coating machine and evacuate it, while setting the substrate temperature to 200°C to reduce outgassing of the aluminum alloy substrate;

[0059] b. The vacuum degree of the coating chamber reaches 3×10 -3 Pa, the ion source was turned on to perform ion cleaning on the substrate surface for 8 min;

[0060] c. Turn on the electron gun to heat and evaporate aluminum oxide, and set the evaporation rate to The evaporation thickness is 10nm;

[0061] d. Turn off the electron gun, rotate the crucible plate to the titanium dioxide position, turn on the electron gun to heat and evaporate the titanium dioxide, and set the evaporation rate to The evaporation thickness is 10nm, and a single cycle of overlapping structure is completed;

[0062] e. Repeat the above steps cd for 19 cycles to complete the protective film evaporation;

[0063] f. After the coating is completed, turn off the power of the electron gun, turn off the power of the ion source, stop the rotation of the turntable, wait for the workpiece to cool down, start the freezer to defrost, and finally inflate it and restore it to atmospheric pressure before taking it out.

[0064] Example 2

[0065] In this embodiment, the thickness of the single-layer aluminum oxide layer in a single cycle is regulated to be 20 nm, and the thickness of the single-layer titanium dioxide layer is 20 nm. After 10 cycles are repeated, the protective film as a whole has a 20-layer structure with a total thickness of 400 nm.

[0066] The other steps are the same as those in Example 1.

[0067] Example 3

[0068] In this embodiment, the thickness of the single-layer aluminum oxide layer in a single cycle is regulated to be 40 nm, and the thickness of the single-layer titanium dioxide layer is 40 nm. Five cycles are repeated, that is, the protective film as a whole has a 10-layer structure with a total thickness of 400 nm.

[0069] The other steps are the same as those in Example 1.

[0070] Example 4

[0071] This embodiment provides a method for preparing an aluminum alloy material, wherein the thickness of a single-layer aluminum oxide layer in a single cycle is regulated to be 100 nm, and the thickness of a single-layer titanium dioxide layer is 100 nm, and two cycles are repeated, so that the protective film as a whole has a four-layer structure.

[0072] The other steps are the same as those in Example 1.

[0073] Example 5

[0074] In this embodiment, the thickness of the single-layer aluminum oxide layer in a single cycle is regulated to be 10 nm, and the thickness of the single-layer titanium dioxide layer is 10 nm. After 10 cycles are repeated, the protective film as a whole has a 20-layer structure with a total thickness of 200 nm.

[0075] The other steps are the same as those in Example 1.

[0076] Example 6

[0077] The difference between this embodiment and embodiment 1 is that the titanium dioxide layer in embodiment 1 is replaced by a niobium pentoxide layer, and the other contents are the same as those in embodiment 1.

[0078] Example 7

[0079] The only difference between this embodiment and embodiment 1 is that the titanium dioxide layer in embodiment 1 is replaced by a zirconium dioxide layer, and the other contents are the same as those in embodiment 1.

[0080] Example 8

[0081] The only difference between this embodiment and embodiment 1 is that the titanium dioxide layer in embodiment 1 is replaced by a tantalum pentoxide layer, and the other contents are the same as those in embodiment 1.

[0082] Comparative Example 1

[0083] A 2000nm thick Cr protective layer was plated on the surface of the aluminum alloy substrate using a magnetron sputtering PVD process.

[0084] Comparative Example 2

[0085] The same method as in Example 1 was used to plate a single-layer aluminum oxide layer with a thickness of 400 nm on the surface of the aluminum alloy substrate.

[0086] Comparative Example 3

[0087] The same method as in Example 1 was used to plate a single-layer titanium dioxide layer with a thickness of 400 nm on the surface of the aluminum alloy substrate.

[0088] The aluminum alloy materials prepared in Example 1 and Comparative Examples 1-3 were placed in a neutral salt spray environment for 96 hours and subjected to salt spray corrosion tests. The results are shown in the attached Figure 2 As shown, Figure 2 a is the substrate prepared in Example 1, Figure 2 b is the substrate prepared in Comparative Example 1, Figure 2 c is the substrate prepared in Comparative Example 2, Figure 2 d is the substrate obtained in Comparative Example 3. Figure 2 It can be seen that the substrate of Example 1 is well protected, with no obvious signs of defect corrosion, that is, titanium dioxide seals the pores of the aluminum oxide material, preventing the penetration and corrosion of chloride ions. The substrate of Comparative Example 1 is obviously salt-corroded at the edge chamfer and the front surface, and the pure aluminum oxide layer of Comparative Example 2 cannot play a protective role. The titanium dioxide layer of Comparative Example 3 can effectively protect the substrate, but there is still film cracking caused by stress release at the corners, which leads to corrosion of the substrate.

[0089] The aluminum alloy materials obtained in Examples 1-8 and Comparative Examples 1-3 were subjected to nanoindentation and vibration friction tests, respectively, and the test results are shown in Table 1. As can be seen from Table 1, Examples 1-4 are all 400nm, and the fewer the number of layers, the lower the overall hardness. When the number of cycle layers in Example 4 is reduced to 4 layers, the protective film begins to fail. The single layer thickness of Example 5 is the same as that of Example 1, but the total thickness is reduced to 200nm. The hardness of the material is greatly affected, and the friction resistance and salt spray corrosion resistance are greatly affected. It can be seen from Examples 6-8 that niobium pentoxide, zirconium dioxide and tantalum pentoxide materials can also replace titanium dioxide in composite stacking structure film layers, which play a role in enhancing hardness and salt spray corrosion resistance. The hardness of the material itself has a direct impact on the overall hardness of the film layer. Comparative Example 1 illustrates that the use of materials with poor salt corrosion resistance cannot isolate chloride ion penetration corrosion even if the thickness is increased. Comparative Example 2 has the same thickness as that of Examples 1-4, which shows that the effect of salt corrosion resistance cannot be achieved by aluminum oxide alone. Comparative Example 3 illustrates that pure titanium dioxide (salt spray corrosion resistant material) as a protective layer cannot avoid stress release at the sharp corners of the edges, resulting in microcracks, i.e., porous defects, causing corrosion and ink layer shedding problems.

[0090] Table 1

[0091] Nanohardness(GPa) Vibration friction 2h Salt spray corrosion test 96h Example 1 20.3 OK OK Example 2 19.1 OK OK Example 3 18.5 OK OK Example 4 17.1 There are slight scratches on the surface There are slight corrosion marks on the surface layer and corners Example 5 17.7 There are slight scratches on the surface There are slight corrosion marks on the surface Example 6 16.6 OK OK Example 7 24.1 OK OK Example 8 21.7 OK OK Comparative Example 1 15.5 OK Film peeling occurs on the surface layer and corners Comparative Example 2 16.3 OK The surface layer and corners are seriously peeling off and there are pitting corrosion Comparative Example 3 13.5 NG Surface layer OK, corners and holes corroded

[0092] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0093] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. An aluminum alloy material, It is characterized in that include: Aluminum alloy substrate; A protective layer, the protective layer is arranged on the surface of the aluminum alloy substrate, the protective layer comprises a plurality of aluminum oxide layers and metal M oxide layers alternately stacked in sequence, the metal M is selected from at least one of titanium, niobium, zirconium and tantalum; The surface of the aluminum alloy substrate is in contact with the aluminum oxide layer, and the outermost layer of the aluminum alloy material is an oxide layer of the metal M. The thickness of the single-layer aluminum oxide layer is 10-20 nm, and the thickness of the single-layer oxide layer of the metal M is 10-20 nm; The total number of the aluminum oxide layers and the oxide layers of the metal M that are alternately stacked in sequence is 20 to 40 layers.

2. The aluminum alloy material according to claim 1, It is characterized in that The ratio of the thickness of the single-layer aluminum oxide layer to the thickness of the single-layer oxide layer of the metal M is 1:

1.

3. The aluminum alloy material according to claim 1, It is characterized in that The total thickness of the protective layer is 350-800 nm.

4. The aluminum alloy material according to any one of claims 1 to 3, It is characterized in that The hardness of the aluminum alloy material is 15-25 GPa.

5. A method for preparing the aluminum alloy material according to any one of claims 1 to 4, It is characterized in that include: An electron beam coating method is used to form a plurality of aluminum oxide layers and metal M oxide layers which are alternately stacked in sequence on the surface of the aluminum alloy substrate.

6. The method according to claim 5, It is characterized in that The evaporation rate of the aluminum oxide layer is 5-10Å / s, and the evaporation rate of the oxide layer of the metal M is 1-5Å / s.

7. An aluminum alloy structural part, It is characterized in that The aluminum alloy material according to any one of claims 1 to 4.

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