A high-strength alloy material based on rail transit vehicles and its processing technology

Abstract

The present invention relates to the technical field of alloy materials, and specifically to a high-strength alloy material based on rail transit vehicles and its processing technology. In the present invention, raw materials are melted and cast to obtain an ingot; the ingot is successively subjected to solution treatment and aging treatment to obtain an alloy material; a composite, mica powder, a curing agent and an epoxy diluent are uniformly mixed, and epoxy resin, an antifoaming agent and a leveling agent are added, followed by ultrasonic treatment to obtain a corrosion-resistant coating; after the surface of the alloy material is successively polished, buffed, cleaned and dried, the corrosion-resistant coating is applied, and after curing, a corrosion-resistant coating is formed to obtain a high-strength alloy material. The high-strength alloy material prepared by the present invention has excellent mechanical properties, and at the same time has excellent corrosion resistance and hydrophobic properties, meeting the application requirements of rail transit vehicles.

Description

Technical Field

[0001] The present invention relates to the technical field of alloy materials, and particularly to a high-strength alloy material for rail transit vehicles and its processing technology. Background Art

[0002] With the increasingly urgent demand for weight reduction of high-speed train car bodies and key components, traditional materials such as aluminum alloys and stainless steels have gradually been replaced by new light metal materials. As an important light metal material, magnesium alloy has a density only 2 / 3 of that of aluminum alloy, and its mechanical properties are comparable to those of aluminum alloy, showing great application potential.

[0003] However, magnesium alloy faces many challenges in application technology. Due to its low potential and active chemical properties, magnesium alloy is prone to corrosion, resulting in a relatively fast degradation rate. Especially in humid or salt spray environments, it is easy to corrode, affecting its service life and limiting its popularization and application. Therefore, effective surface treatment is required. In addition, the ignition point of magnesium alloy is relatively low, significantly increasing the difficulty of fire safety design for rail transit vehicles; the plasticity of high-strength magnesium alloy is poor during forming processing, especially at high temperatures, its forming performance will be limited, resulting in low production efficiency.

[0004] Magnesium alloy has poor thermal conductivity, a large coefficient of thermal expansion, and is easy to oxidize. During the welding process, it is prone to defects such as coarse grains, large thermal stress, and oxidation inclusions. At the same time, its process adaptability for welding with dissimilar metals is poor, thus limiting its application in large components.

[0005] Therefore, we propose a high-strength alloy material for rail transit vehicles and its processing technology. Summary of the Invention

[0006] The purpose of the present invention is to provide a high-strength alloy material for rail transit vehicles and its processing technology to solve the problems raised in the prior art.

[0007] To achieve the above purpose, the present invention provides the following technical solutions:

[0008] A processing technology for a high-strength alloy material for rail transit vehicles includes the following steps:

[0009] Step S1: Melting the raw materials at 740 - 760 °C, cooling to 720 - 730 °C after melting, holding for 10 - 20 min, and casting to obtain an ingot;

[0010] Step S2: Sequentially performing solution treatment and aging treatment on the ingot to obtain an alloy material;

[0011] Step S3: Mix the complex, mica powder, curing agent, and epoxy diluent evenly, add epoxy resin, defoamer, and leveling agent, and perform ultrasonic treatment to obtain a corrosion-resistant coating; after the surface of the alloy material is successively polished, buffed, cleaned, and dried, apply the corrosion-resistant coating, and after curing, form a corrosion-resistant coating to obtain a high-strength alloy material.

[0012] Further, the raw materials include the following chemical components by mass percentage: Zn: 1-2%, Y: 3.6-4.2%, Gd: 1.2-1.4%, Zr: 0.4-0.6%, Ca: 0.05-0.10%, Sn: 0.3-0.5%, and the balance is Mg.

[0013] Further, the solution treatment process is to hold at 515-535 °C for 8-12 h and then water quench.

[0014] Further, the aging treatment process is to hold at 220-260 °C for 10-14 h and then air cool.

[0015] Further, the corrosion-resistant coating includes the following weight components: 50-60 parts of epoxy resin, 5-15 parts of complex, 10-20 parts of mica powder, 10-20 parts of epoxy diluent, 8-12 parts of curing agent, 0.2-0.3 parts of defoamer, and 0.1-0.2 parts of leveling agent.

[0016] Further, the epoxy resin is E51 epoxy resin.

[0017] Further, the preparation method of the complex is as follows:

[0018] Step (1): Mix polyethyleneimine and phosphate buffer evenly, adjust the pH of the system to 5.0-5.5 with nitric acid, add caffeic acid and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, react for 2-3 h to obtain a modified polyethyleneimine solution, dropwise add a mixed solution of graphene oxide and DMF, finish dropping in 30-50 min, react for 6-8 h, cool to room temperature, and after filtration, washing, and drying, obtain modified graphene oxide;

[0019] Step (2): Under nitrogen protection, mix salicylaldehyde and absolute ethanol evenly, dropwise add ethylenediamine, finish dropping in 30-50 min, react at 70-80 °C for 3-5 h, cool to room temperature, and after filtration, washing, and drying, obtain a hydroxyl-containing monomer; under nitrogen protection, mix the hydroxyl-containing monomer, castor oil triglycidyl ether, and tetrabutylammonium bromide evenly, react at 70-80 °C for 4-6 h, cool to room temperature, and after filtration, washing, and drying, obtain a hyperbranched epoxy compound;

[0020] Step (3): Ultrasonically disperse the modified graphene oxide in deionized water, adjust the pH to 9 - 10 using sodium hydroxide, add the hyperbranched epoxide and mix evenly. React for 6 - 8 h, then add octadecanethiol, perfluorodecanethiol and 2-hydroxy-2-methylpropiophenone and mix evenly. After ultraviolet irradiation, washing, filtration and drying, a composite is obtained.

[0021] In the above technical solution, the amino group in polyethyleneimine reacts with the carboxyl group in caffeic acid to introduce a catechol group with adhesion properties. Then, using polyethyleneimine containing a large number of amino groups as a bridge, it reacts with the epoxy group in graphene oxide to introduce amino groups onto the graphene oxide, obtaining modified graphene oxide. Then, the amino group on the modified graphene oxide reacts with the hyperbranched epoxide. Finally, octadecanethiol and perfluorodecanethiol are added, and through thiol-ene click reaction, hydrophobic long-chain alkyl groups and fluorine-containing groups are introduced to obtain a composite with anti-corrosion and hydrophobic properties.

[0022] Further, in the step (1), the mass ratio of polyethyleneimine, phosphate buffer, caffeic acid and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide is 1:(15 - 20):(0.5 - 0.7):(0.9 - 1.0), and the concentration of nitric acid is 1 M.

[0023] Further, in the step (1), the concentration of the mixed solution is 10 mg / mL, and its mass is 100 - 120 times the mass of polyethyleneimine.

[0024] Further, in the step (2), the mass ratio of salicylaldehyde, absolute ethanol and ethylenediamine is 1:(8 - 10):(0.25 - 0.30).

[0025] Further, in the step (2), the mass ratio of the hydroxyl-containing monomer, castor oil triglycidyl ether and tetrabutylammonium bromide is 1:(8 - 10):(0.1 - 0.3).

[0026] Further, in the step (3), the mass ratio of the modified graphene oxide, deionized water and hyperbranched epoxide is 1:(200 - 300):(0.4 - 0.6).

[0027] Further, in the step (3), the mass ratio of the hyperbranched epoxide, octadecanethiol, perfluorodecanethiol and 2-hydroxy-2-methylpropiophenone is 1:(0.5 - 1.0):(1 - 2):(0.1 - 0.3).

[0028] Further, in the step (3), the process conditions for ultraviolet irradiation are: irradiation wavelength 360 - 400 nm, irradiation time 0.5 - 1.0 h, irradiation intensity 20 - 35 mW / cm 2 .

[0029] Further, the epoxy diluent is 1,6 - hexanediol diglycidyl ether.

[0030] Further, the curing agent is isophorone diamine curing agent.

[0031] Further, the thickness of the corrosion - resistant coating is 50 - 100 μm.

[0032] Further, the curing process conditions are curing at 120 - 150 °C for 4 - 8 h.

[0033] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0034] 1. For a high - strength alloy material and its processing technology based on rail transit vehicles of the present invention, through the reaction of amino groups in polyethyleneimine with carboxyl groups in caffeic acid, catechol groups and double bonds with adhesion performance are introduced. These can not only chelate with metal ions but also increase the cross - linking density inside the coating, resulting in a rough surface morphology. This roughness helps to enhance the adhesion between the coating and the substrate, thereby preparing a polymer anti - corrosion coating with continuous and long - lasting adhesion performance, significantly improving the anti - corrosion effect. Then, using polyethyleneimine containing a large number of amino groups as a bridge, it reacts with epoxy groups in graphene oxide to introduce amino groups onto the surface of graphene oxide, obtaining modified graphene oxide.

[0035] Based on the condensation reaction of salicylaldehyde and ethylenediamine, an A2 monomer with two functional groups, namely a hydroxyl - containing monomer, is obtained. Introducing heteroatoms (N atoms) provides a basis for subsequent rapid curing and anti - corrosion performance. Then, the hydroxyl - containing monomer and castor oil triglycidyl ether undergo a ring - opening reaction through proton - transfer polymerization, thereby generating a macromolecular structure with less intermolecular chain entanglement and low viscosity, obtaining a hyperbranched epoxy compound with double bonds. Then, through the reaction of amino groups on the modified graphene oxide with the hyperbranched epoxy compound, the compatibility between the modified graphene oxide and the epoxy resin matrix can be improved. Finally, octadecanethiol and perfluorodecanethiol are added, and through thiol - ene click reaction, hydrophobic long - chain alkyl groups and fluorine - containing groups are introduced, significantly improving the hydrophobicity of the material, helping to reduce the penetration of moisture and enhancing the anti - corrosion performance, especially the application effect in humid environments.

[0036] 2. A high-strength alloy material based on rail transit vehicles and its processing technology according to the present invention. The addition of Zn element can increase the fluidity of the alloy liquid, better realize the formability of the material, and reduce the occurrence of defects; Y can enhance the high-temperature resistance and oxidation resistance of the magnesium alloy, and improve the stability of the alloy in high-temperature environments. At the same time, Y can also improve the corrosion resistance of the alloy and extend its service life; Gd can be used as a strengthening element in the alloy to promote the precipitation of the second phase, improve the strength and toughness of the alloy, especially showing good performance under high-temperature conditions, thereby further enhancing the mechanical properties of the material; Zr element can effectively refine the grains and improve the tensile strength and toughness of the material; the addition of Ca element can significantly improve the flame retardancy of the magnesium alloy, making the material remain relatively intact under high-temperature oxidation conditions, which is beneficial to improving safety; the addition of Sn element can significantly refine the grains of the as-cast alloy, promote the precipitation of the second phase, help improve the strength and fatigue resistance of the material, and improve the overall mechanical properties. By reasonably adding these elements, the high-strength alloy material prepared by the present invention has excellent performance in terms of mechanical properties, flame retardancy, corrosion resistance, etc., meeting the application requirements of rail transit vehicles. Specific Embodiments

[0037] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0038] In this embodiment, Mg: pure magnesium ingot, grade Mg99.98; Zn: pure zinc ingot, grade Zn99.995; Y: Mg-Y master alloy, grade MgY30; Gd: Mg-Gd master alloy, grade MgGd30; Zr: Mg-Zr master alloy, grade MgZr25; Ca: Mg-Ca master alloy, grade magnesium calcium 30; Sn: Mg-Sn master alloy, grade MgSn20;; Epoxy resin: grade E51; Polyethyleneimine: CAS No. 9002-98-6; Graphene oxide: thickness 1-3 nm, diameter 4-7 μm, number of layers 2-5 layers; Mica powder: particle size of 1250 mesh; Defoaming agent: BYK-057; Levelling agent: BYK-333.

[0039] In the following examples and comparative examples, 1 part is equal to 10 g.

[0040] Example 1: A processing technology for a high-strength alloy material based on rail transit vehicles, including the following processes:

[0041] Step S1: Melting the raw materials at 740 °C, cooling to 720 °C after melting, holding for 10 min, and casting to obtain an ingot;

[0042] Step S2: Subjecting the ingot to solution treatment (holding at 515 °C for 8 h, water quenching) and aging treatment (holding at 220 °C for 10 h, air cooling) in sequence to obtain an alloy material;

[0043] Step S3: Mixing 5 parts of the composite, 10 parts of mica powder, 8 parts of curing agent, and 10 parts of epoxy diluent evenly, adding 50 parts of epoxy resin, 0.2 part of defoaming agent, and 0.1 part of leveling agent, and performing ultrasonic treatment to obtain a corrosion-resistant coating; After the surface of the alloy material is polished, polished, cleaned, and dried in sequence, the corrosion-resistant coating is applied, and after curing (curing at 120 °C for 8 h), a corrosion-resistant coating is formed to obtain a high-strength alloy material; The raw materials include the following chemical components by mass percentage: Zn: 1%, Y: 3.6%, Gd: 1.2%, Zr: 0.4%, Ca: 0.05%, Sn: 0.3%, and the balance is Mg;

[0044] The preparation method of the composite is as follows:

[0045] Step (1): Mixing 5 parts of polyethyleneimine and 75 parts of phosphate buffer evenly, adjusting the pH of the system to 5.0 with 1 M nitric acid, adding 2.5 parts of caffeic acid and 4.5 parts of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, reacting for 2 h to obtain a modified polyethyleneimine solution, dropping 500 parts of a mixed solution of 10 mg / mL graphene oxide and DMF, dropping it within 1 h, reacting for 6 h, cooling to room temperature, and obtaining modified graphene oxide after filtration, washing, and drying;

[0046] Step (2): Under nitrogen protection, mixing 1 part of salicylaldehyde and 8 parts of absolute ethanol evenly, dropping 0.25 part of ethylenediamine, dropping it within 30 min, reacting at 70 °C for 3 h, cooling to room temperature, and obtaining a hydroxyl-containing monomer after filtration, washing, and drying; Under nitrogen protection, mixing 0.25 part of the hydroxyl-containing monomer, 2 parts of castor oil triglycidyl ether, and 0.025 part of tetrabutylammonium bromide evenly, reacting at 70 °C for 4 h, cooling to room temperature, and obtaining a hyperbranched epoxy compound after filtration, washing, and drying;

[0047] Step (3): Ultrasonically dispersing 5 parts of modified graphene oxide in 1000 parts of deionized water, adjusting the pH to 9 with sodium hydroxide, adding 2 parts of hyperbranched epoxy compound and mixing evenly, reacting for 6 h, then adding 1 part of octadecanethiol, 2 parts of perfluorodecanethiol, and 0.2 part of 2-hydroxy-2-methylpropiophenone and mixing evenly, and subjecting it to ultraviolet light irradiation (irradiation wavelength 360 nm, irradiation time 0.5 h, irradiation intensity 20 mW / cm 2 ), washing, filtering, and drying to obtain the composite.

[0048] Example 2: A processing technology for a high-strength alloy material based on rail transit vehicles, including the following processes:

[0049] Step S1: Melting the raw materials at 750 °C, cooling to 725 °C after melting, holding for 15 min, and casting to obtain an ingot;

[0050] Step S2: Subjecting the ingot to solution treatment (holding at 520 °C for 10 h, water quenching) and aging treatment (holding at 240 °C for 12 h, air cooling) in sequence to obtain an alloy material;

[0051] Step S3: Mixing 10 parts of a composite, 15 parts of mica powder, 10 parts of a curing agent, and 15 parts of an epoxy diluent evenly, adding 55 parts of epoxy resin, 0.25 parts of an antifoaming agent, and 0.15 parts of a leveling agent, and performing ultrasonic treatment to obtain a corrosion-resistant coating; after the surface of the alloy material is polished, polished, cleaned, and dried in sequence, the corrosion-resistant coating is coated, and after curing (curing at 140 °C for 6 h), a corrosion-resistant coating is formed to obtain a high-strength alloy material; the raw materials include the following chemical components by mass percentage: Zn: 1.5%, Y: 4%, Gd: 1.3%, Zr: 0.5%, Ca: 0.08%, Sn: 0.4%, and the balance is Mg;

[0052] The preparation method of the composite is as follows:

[0053] Step (1): Mixing 10 parts of polyethyleneimine and 180 parts of phosphate buffer evenly, adjusting the pH of the system to 5.3 with nitric acid, adding 6 parts of caffeic acid and 9.5 parts of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, reacting for 2.5 h to obtain a modified polyethyleneimine solution, dropping 1100 parts of a mixed solution of 10 mg / mL graphene oxide and DMF, dropping it in 1.5 h, reacting for 7 h, cooling to room temperature, and after filtration, washing, and drying, obtaining modified graphene oxide;

[0054] Step (2): Under nitrogen protection, mixing 1 part of salicylaldehyde and 9 parts of absolute ethanol evenly, dropping 0.28 parts of ethylenediamine, dropping it in 40 min, reacting at 75 °C for 4 h, cooling to room temperature, and after filtration, washing, and drying, obtaining a hydroxyl-containing monomer; under nitrogen protection, mixing 0.6 parts of the hydroxyl-containing monomer, 5.4 parts of castor oil triglycidyl ether, and 0.12 parts of tetrabutylammonium bromide evenly, reacting at 75 °C for 5 h, cooling to room temperature, and after filtration, washing, and drying, obtaining a hyperbranched epoxy compound;

[0055] Step (3): Ultrasonically disperse 10 parts of modified graphene oxide in 2500 parts of deionized water, adjust the pH to 9.5 using sodium hydroxide, add 5 parts of hyperbranched epoxy compound and mix evenly, react for 7 h, then add 4 parts of octadecanethiol and 7.5 parts of 2-hydroxy-2-methylpropiophenone and mix evenly. After ultraviolet light irradiation (irradiation wavelength 380 nm, irradiation time 0.8 h, irradiation intensity 25 mW / cm 2 ), washing, filtration, and drying, a composite is obtained.

[0056] Example 3: A processing technology for a high-strength alloy material based on rail transit vehicles, including the following processes:

[0057] Step S1: Melting the raw materials at 760 °C, cooling to 730 °C after melting, holding for 20 min, and casting to obtain an ingot;

[0058] Step S2: Sequentially performing solution treatment (holding at 535 °C for 12 h, water quenching) and aging treatment (holding at 260 °C for 14 h, air cooling) on the ingot to obtain an alloy material;

[0059] Step S3: Mix 15 parts of the composite, 20 parts of mica powder, 12 parts of curing agent, and 20 parts of epoxy diluent evenly, add 60 parts of epoxy resin, 0.3 part of defoaming agent, and 0.2 part of leveling agent, and perform ultrasonic treatment to obtain a corrosion-resistant coating; after sequentially grinding, polishing, cleaning, and drying the surface of the alloy material, coat the corrosion-resistant coating, and after curing (curing at 150 °C for 4 h), a corrosion-resistant coating is formed to obtain a high-strength alloy material; the raw materials include the following chemical components by mass percentage: Zn: 2%, Y: 4.2%, Gd: 1.4%, Zr: 0.6%, Ca: 0.10%, Sn: 0.5%, and the balance is Mg;

[0060] The preparation method of the composite is as follows:

[0061] Step (1): Mix 15 parts of polyethyleneimine and 300 parts of phosphate buffer evenly, adjust the pH of the system to 5.5 using nitric acid, add 10.5 parts of caffeic acid and 15 parts of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, react for 3 h to obtain a modified polyethyleneimine solution, dropwise add 1800 parts of a mixed solution of 10 mg / mL graphene oxide and DMF, finish dropping in 2 h, react for 8 h, cool to room temperature, and after filtration, washing, and drying, obtain modified graphene oxide;

[0062] Step (2): Under nitrogen protection, 1 part of salicylaldehyde and 10 parts of absolute ethanol were mixed evenly, 0.3 part of ethylenediamine was added dropwise, and the addition was completed in 50 min. The reaction was carried out at 80 °C for 5 h, and then cooled to room temperature. After filtration, washing, and drying, a hydroxyl-containing monomer was obtained. Under nitrogen protection, 1 part of the hydroxyl-containing monomer, 10 parts of castor oil triglycidyl ether, and 0.3 part of tetrabutylammonium bromide were mixed evenly. The reaction was carried out at 80 °C for 6 h, and then cooled to room temperature. After filtration, washing, and drying, a hyperbranched epoxy compound was obtained.

[0063] Step (3): 15 parts of modified graphene oxide were ultrasonically dispersed in 4500 parts of deionized water, the pH was adjusted to 10 using sodium hydroxide, 9 parts of the hyperbranched epoxy compound were added and mixed evenly, and the reaction was carried out for 8 h. Then, 9 parts of octadecanethiol and 18 parts of 2-hydroxy-2-methylpropiophenone were added and mixed evenly. After ultraviolet light irradiation (irradiation wavelength 400 nm, irradiation time 1.0 h, irradiation intensity 35 mW / cm 2 ), washing, filtration, and drying, a composite was obtained.

[0064] Comparative Example 1: The raw materials included the following chemical components by mass percentage: Zn: 0.5%, Y: 2%, Gd: 0.5%, Zr: 0.2%, Ca: 0.01%, Sn: 0.2%, and the balance was Mg. Other steps and processes were the same as those in Example 1.

[0065] Comparative Example 2: A processing technology for a high-strength alloy material based on rail transit vehicles included the following processes:

[0066] Compared with Example 2, in Comparative Example 2, the composite was replaced with graphene oxide of the same mass, and other steps were the same as those in Example 2.

[0067] Comparative Example 3: A processing technology for a high-strength alloy material based on rail transit vehicles included the following processes:

[0068] Compared with Example 2, Comparative Example 3 did not include Step (2) and did not add the hyperbranched epoxy compound in Step (3), and other steps were the same as those in Example 2.

[0069] Comparative Example 4: A processing technology for a high-strength alloy material based on rail transit vehicles included the following processes:

[0070] The preparation method of the composite was as follows:

[0071] Step (1): Mix 10 parts of polyethyleneimine and 180 parts of phosphate buffer evenly, adjust the pH of the system to 5.3 with nitric acid, add 6 parts of caffeic acid and 9.5 parts of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, react for 2.5 h to obtain a modified polyethyleneimine solution, dropwise add 1100 parts of a mixed solution of 10 mg / mL graphene oxide and DMF, finish dropping in 1.5 h, react for 7 h, cool to room temperature, and after filtration, washing and drying, obtain modified graphene oxide;

[0072] Step (2): Under nitrogen protection, mix 1 part of salicylaldehyde and 9 parts of absolute ethanol evenly, dropwise add 0.28 parts of ethylenediamine, finish dropping in 40 min, react at 75 °C for 4 h, cool to room temperature, and after filtration, washing and drying, obtain a hydroxyl-containing monomer; Under nitrogen protection, mix 0.6 parts of the hydroxyl-containing monomer, 5.4 parts of castor oil triglycidyl ether and 0.12 parts of tetrabutylammonium bromide evenly, react at 75 °C for 5 h, cool to room temperature, and after filtration, washing and drying, obtain a hyperbranched epoxy compound;

[0073] Step (3): Ultrasonically disperse 10 parts of modified graphene oxide in 2500 parts of deionized water, adjust the pH to 9.5 with sodium hydroxide, add 1 part of the hyperbranched epoxy compound and mix evenly, react for 7 h, then add 4 parts of octadecanethiol and 7.5 parts of 2-hydroxy-2-methylpropiophenone and mix evenly, and after ultraviolet light irradiation (irradiation wavelength 380 nm, irradiation time 0.8 h, irradiation intensity 25 mW / cm2), washing, filtration and drying, obtain a composite;

[0074] Compared with Example 2, in step (3) of Comparative Example 4, the mass ratio of modified graphene oxide to hyperbranched epoxy compound is 1:0.1, and other steps are the same as those in Example 2.

[0075] Experiment: Take the high-strength alloy materials obtained in Examples 1-3 and Comparative Examples 1-4, prepare specimens, and detect their properties respectively and record the detection results:

[0076] Determine the tensile strength according to GB / T228.1-2010 "Metallic materials - Tensile testing - Part 1: Method of test at room temperature". The specimen size is a bar with a diameter of 16 mm, and the room temperature tensile test is carried out on a CMT-5105 universal testing machine;

[0077] Determine the corrosion resistance according to GB / T 1771-2007 "Paints and varnishes - Determination of resistance to neutral salt spray". Experimental procedure: The specimen size is ϕ10 mm×2 mm. Draw two cross cracks on the coating surface, and then place it in a salt spray test chamber. Under the conditions of a test temperature of (35±2) °C and a pH value of about 6.7 - 7.5, use 5% NaCl solution as the spray medium. After 720 h of salt spray test, evaluate the performance of the specimen.

[0078] The contact angle was measured using a JC2000DM type contact angle measuring instrument, and the volume of deionized water was 2 μL.

[0079] The test results are as follows:

[0080]

[0081] From the data in the above table, the following conclusions can be clearly obtained:

[0082] 1. Compared with Examples 1-3, the tensile strength of the product obtained in Comparative Example 1 decreased, indicating that the performance of the alloy material prepared by the present invention is affected by its component ratio. Selecting the component ratio within the said range results in a product with better performance.

[0083] 2. Compared with Examples 1-3, the hydrophobic and corrosion-resistant properties of the products obtained in Comparative Examples 2 and 3 both decreased, indicating that the composite phase prepared by the present invention is more superior in terms of hydrophobic effect and corrosion resistance than graphene oxide, thus effectively improving the anti-corrosion performance of the magnesium alloy. At the same time, adding hyperbranched epoxide in the present invention can further improve the corrosion resistance and provide more reaction sites, which is beneficial to the grafting of hydrophobic long-chain monomers and fluorine-containing monomers, thereby further enhancing the hydrophobic effect.

[0084] 3. Compared with Examples 1-3, the hydrophobic and corrosion-resistant properties of the product obtained in Comparative Example 4 both decreased, indicating that when the addition amount of hyperbranched epoxide is reduced, the corrosion resistance and hydrophobic properties of the material will decrease.

[0085] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, in any aspect, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present invention.

Claims

1. A processing technology for high-strength alloy materials for rail transit vehicles, characterized in that: The steps include: Step S1: smelting the raw material at 740-760°C, cooling it to 720-730°C after melting, keeping it warm for 10-20 minutes, and casting it to obtain an ingot; Step S2: subjecting the ingot to solution treatment and aging treatment in sequence to obtain an alloy material; Step S3: uniformly mixing the composite, mica powder, curing agent and epoxy diluent, adding epoxy resin, defoaming agent and leveling agent, and performing ultrasonic treatment to obtain a corrosion-resistant coating; grinding, polishing, cleaning and drying the surface of the alloy material in sequence, coating the corrosion-resistant coating, and forming a corrosion-resistant coating after curing to obtain a high-strength alloy material; The raw material comprises the following chemical components in mass percentage: Zn: 1-2%, Y: 3.6-4.2%, Gd: 1.2-1.4%, Zr: 0.4-0.6%, Ca: 0.05-0.10%, Sn: 0.3-0.5%, and the balance is Mg; The preparation method of the composite is as follows: Step (1): uniformly mix polyethyleneimine and phosphate buffer, use nitric acid to adjust the system pH to 5.0-5.5, add caffeic acid and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, react for 2-3 hours to obtain a modified polyethyleneimine solution, add a mixed solution of graphene oxide and DMF dropwise for 1-2 hours, react for 6-8 hours, cool to room temperature, filter, wash and dry to obtain modified graphene oxide; Step (2): under nitrogen protection, salicylaldehyde and anhydrous ethanol are mixed evenly, ethylenediamine is added dropwise for 30-50 minutes, the mixture is reacted at 70-80° C. for 3-5 hours, cooled to room temperature, filtered, washed, and dried to obtain a hydroxyl-containing monomer; the hydroxyl-containing monomer, castor oil triglycidyl ether, and tetrabutylammonium bromide are mixed evenly, the mixture is reacted at 70-80° C. for 4-6 hours, cooled to room temperature, filtered, washed, and dried to obtain a hyperbranched epoxy compound; Step (3): ultrasonically dispersing the modified graphene oxide in deionized water, adjusting the pH to 9-10 with sodium hydroxide, adding a hyperbranched epoxy compound and mixing evenly, reacting for 6-8 hours, then adding octadecyl mercaptan, perfluorodecyl mercaptan and 2-hydroxy-2-methylpropiophenone and mixing evenly, irradiating with ultraviolet light, washing, filtering and drying to obtain a composite; In step (3), the mass ratio of modified graphene oxide, deionized water and hyperbranched epoxy compound is 1:(200-300):(0.4-0.6).

2. The processing technology of high-strength alloy material based on rail transit vehicles according to claim 1 is characterized in that: The solution treatment process is to keep the temperature at 515-535° C. for 8-12 hours and then quench in water.

3. The processing technology of high-strength alloy material for rail transit vehicles according to claim 1 is characterized in that: The aging treatment process is to keep the temperature at 220-260° C. for 10-14 hours and then air cool.

4. The processing technology of high-strength alloy material for rail transit vehicles according to claim 1 is characterized in that: The corrosion-resistant coating comprises the following components by weight: 50-60 parts of epoxy resin, 5-15 parts of compound, 10-20 parts of mica powder, 10-20 parts of epoxy diluent, 8-12 parts of curing agent, 0.2-0.3 parts of defoaming agent and 0.1-0.2 parts of leveling agent.

5. The processing technology of high-strength alloy material based on rail transit vehicles according to claim 4 is characterized in that: The epoxy resin is E51 epoxy resin.

6. The processing technology of high-strength alloy material for rail transit vehicles according to claim 4 is characterized in that: The epoxy diluent is 1,6-hexanediol diglycidyl ether.

7. The processing technology of high-strength alloy material for rail transit vehicles according to claim 1 is characterized in that: In step (2), the mass ratio of the hydroxyl-containing monomer, castor oil triglycidyl ether and tetrabutylammonium bromide is 1:(8-10):(0.1-0.3).

8. A high-strength alloy material for rail transit vehicles obtained by the processing technology according to any one of claims 1 to 7.

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