A graphene-enhanced magnesium alloy, a magnesium alloy prefabricated plate and a preparation method thereof

Abstract

The present invention belongs to the technical field of alloy material preparation, and specifically relates to a graphene-enhanced magnesium alloy, a magnesium alloy prefabricated plate and a preparation method thereof. The graphene-enhanced magnesium alloy comprises graphene and an alloy; wherein the elements in the alloy include 4.7%-5.5% aluminum, 2.7%-3.3% zinc, 1%-2% manganese and the remainder of magnesium and unavoidable impurities according to mass fraction; the addition amount of graphene is 1%-4.5% of the alloy mass. The compressive strength and hardness of the graphene-enhanced magnesium alloy are significantly improved compared with ordinary magnesium alloys, the compressive strength can be increased by about 32%, and the hardness can be increased by about 22.9%; and the toughness and elongation are not affected.

Description

Technical Field

[0001] The present invention belongs to the technical field of alloy material preparation, and in particular relates to a graphene-reinforced magnesium alloy, a magnesium alloy prefabricated plate and a preparation method thereof. Background Art

[0002] As a lightweight and high-strength material, magnesium alloy has broad application prospects in aerospace, automobile manufacturing, electronic communications and other fields. However, the strength and hardness of magnesium alloy are relatively low, which limits its application in some high-demand occasions. In order to improve the mechanical properties of magnesium alloy, researchers have conducted a lot of exploration and practice, including alloying, pressure processing, heat treatment, grain refinement, adding reinforcement materials and other methods.

[0003] Among them, adding reinforcement materials is a relatively common method, which is to add ceramic particles, fibers or whiskers and other reinforcement phases to magnesium alloys, which can significantly improve the strength and elastic modulus of magnesium alloys, improve wear resistance and improve high temperature strength and creep resistance. However, these reinforcement materials often have problems such as poor compatibility with the magnesium alloy matrix and difficulty in processing, which affects the overall performance and application range of magnesium alloys.

[0004] In recent years, graphene, as a new type of nanomaterial, has attracted much attention due to its excellent mechanical, electrical and thermal properties. Graphene has extremely high strength and hardness, as well as good flexibility and ductility, and is considered to be one of the ideal reinforcement materials. Summary of the invention

[0005] Based on this, the present invention uses a suitable dispersant to evenly disperse an appropriate amount of graphene in the alloy, and then prepares the graphene-reinforced magnesium alloy by liquid metallurgy. The prepared reinforced magnesium alloy maintains the excellent flexibility and ductility of the alloy while significantly improving the strength and hardness compared to ordinary magnesium alloys.

[0006] In order to achieve the above object, the present invention can adopt the following technical solutions:

[0007] On one hand, the present invention provides a graphene-enhanced magnesium alloy, comprising graphene and an alloy; wherein the elements in the alloy include, by mass fraction, 4.7%-5.5% aluminum, 2.7%-3.3% zinc, 1%-2% manganese and the remainder of magnesium and unavoidable impurities; and the addition amount of graphene is 1%-4.5% of the alloy mass.

[0008] Preferably, the above-mentioned graphene-enhanced magnesium alloy satisfies one or more of the following conditions: (a) the elements in the alloy include 5% aluminum, 3% zinc, 1.5% manganese and the remainder magnesium and unavoidable impurities in terms of mass fraction; (b) the added amount of graphene is 3% of the alloy mass.

[0009] On the other hand, the present invention provides a method for preparing a graphene-enhanced magnesium alloy, comprising: (1) mixing graphene powder, a dispersant and water to obtain a graphene suspension; (2) mixing the graphene suspension and alloy powder, and pressing to obtain a composite material blank; (3) sintering the composite material blank, and performing a solid solution treatment to obtain a graphene-enhanced magnesium alloy.

[0010] Preferably, the dispersant is selected from one or more of sodium polyacrylate, potassium polyacrylate, polyvinyl alcohol or polyethylene glycol.

[0011] Preferably, in the above graphene suspension, the mass percentage of graphene powder is 1%-4.5%, and the mass percentage of dispersant is 0.5%-1.5%.

[0012] More preferably, in the above graphene suspension, the mass percentage of graphene powder is 3%, and the mass percentage of dispersant is 1%.

[0013] Preferably, the above preparation method satisfies one or more of the following conditions: (i) in step (1), ultrasound is used to assist in the mixing process; (ii) in step (2), the pressing pressure is 2000 N / cm 2 -2500N / cm 2 ; (iii) in step (3), the sintering temperature is 650℃-750℃; (iv) in step (3), the solution treatment temperature is 550℃-650℃.

[0014] More preferably, the frequency of the ultrasound is 15kHz-25kHz.

[0015] In another aspect, the present invention provides a magnesium alloy prefabricated plate, which is prepared from the graphene-reinforced magnesium alloy of the present invention.

[0016] The beneficial effects of the present invention include: the graphene-enhanced magnesium alloy provided by the present invention has significantly improved compressive strength and hardness compared with ordinary magnesium alloys (not enhanced by graphene), the compressive strength can be increased by about 32%, and the hardness can be increased by about 22.9%; and the graphene-enhanced magnesium alloy does not affect the toughness and elongation of ordinary magnesium alloys. DETAILED DESCRIPTION

[0017] The examples are provided to better illustrate the present invention, but the present invention is not limited to the examples. Therefore, those skilled in the art may make non-essential improvements and adjustments to the implementation scheme according to the above invention content, which still fall within the protection scope of the present invention.

[0018] The terms used herein are only used to describe specific embodiments and are not intended to limit the present disclosure. Unless the context has a significantly different meaning, expressions in the singular include expressions in the plural. As used herein, it should be understood that terms such as "include", "have", "include" are intended to indicate the presence of features, numbers, operations, components, parts, elements, materials or combinations. The terms of the present invention are disclosed in the specification, and are not intended to exclude the possibility that one or more other features, numbers, operations, components, parts, elements, materials or combinations thereof may exist or may be added. As used herein, " / " may be interpreted as "and" or "or", depending on the circumstances.

[0019] An embodiment of the present invention provides a graphene-enhanced magnesium alloy, comprising graphene and an alloy; wherein the elements in the alloy include, by mass fraction, 4.7%-5.5% aluminum, 2.7%-3.3% zinc, 1%-2% manganese and the remainder of magnesium and unavoidable impurities; the added amount of graphene is 1%-4.5% of the alloy mass.

[0020] It should be noted that the present invention uses a suitable dispersant to evenly disperse an appropriate amount of graphene in the alloy, and then prepares a graphene-enhanced magnesium alloy by liquid metallurgy. The prepared enhanced magnesium alloy maintains the excellent flexibility and ductility of the alloy while greatly improving the strength and hardness compared with ordinary magnesium alloys; wherein, the amount of graphene added is 1%-4.5% of the alloy mass, such as 1.2%, 1.5%, 2%, 2.5%, 3%, 3.5% or 4%, etc. If the amount of graphene added is too little, the improvement effect is not significant. If the amount of graphene added is too much, the graphene is difficult to be evenly dispersed, which will affect the performance of the alloy; in addition, the aluminum in the alloy of the present invention can be 4.7%-5.5%, such as 5%, 5.2% or 5.4%, etc., zinc can be 2.7%-3.3%, such as 3%, 3.1% or 3.2%, etc., and manganese can be 1%-2%, such as 1.2%, 1.5% or 1.7%, etc.

[0021] In some specific examples, the above-mentioned graphene-enhanced magnesium alloy satisfies one or more of the following conditions: (a) the elements in the alloy include 5% aluminum, 3% zinc, 1.5% manganese and the remainder magnesium and unavoidable impurities by mass fraction; (b) the added amount of graphene is 3% of the alloy mass.

[0022] It should be noted that in the present invention, when the graphene-enhanced magnesium alloy meets the above conditions at the same time, the mechanical properties of the prepared graphene-enhanced magnesium alloy are better than those of other proportions. The compressive strength of the graphene-enhanced magnesium alloy at this ratio can be increased by about 32% and the hardness can be increased by about 22.9% compared with ordinary magnesium alloys.

[0023] The embodiment of the present invention also provides a method for preparing a graphene-enhanced magnesium alloy, comprising: (1) mixing graphene powder, a dispersant and water to obtain a graphene suspension; (2) mixing the graphene suspension and alloy powder, and pressing to obtain a composite material blank; (3) sintering the composite material blank, and solution treating to obtain a graphene-enhanced magnesium alloy.

[0024] It should be noted that the method of adding graphene to the alloy in the present invention is a liquid metallurgical method, in which the graphene is first dispersed by using a suitable dispersant, and then evenly dispersed in the alloy powder, and then pressed, sintered, and solution treated to obtain the graphene-reinforced magnesium alloy; in addition, the above operations are all conventional operating methods in the art and have no specific meaning.

[0025] In some specific examples, the dispersant is selected from one or more of sodium polyacrylate, potassium polyacrylate, polyvinyl alcohol or polyethylene glycol.

[0026] It should be noted that different dispersants suitable for use in the present invention have different effects. Among them, the dispersing effect of sodium polyacrylate and potassium polyacrylate is better than that of polyvinyl alcohol or polyethylene glycol. The graphene-reinforced magnesium alloy prepared based on sodium polyacrylate and potassium polyacrylate has a significantly better effect on improving the strength and hardness of the magnesium alloy than the graphene-reinforced magnesium alloy prepared based on polyvinyl alcohol or polyethylene glycol. In addition, the graphene-reinforced magnesium alloy prepared with sodium polyacrylate dispersant has the best mechanical properties.

[0027] In some specific examples, in the above graphene suspension, the mass percentage of graphene powder is 1%-4.5%, and the mass percentage of dispersant is 0.5%-1.5%.

[0028] It should be noted that when preparing graphene powder into a graphene suspension, the mass percentage of graphene powder is preferably 1%-4.5%, such as 1.5%, 2%, 2.5%, 3%, 3.5% or 4%, and the mass percentage of dispersant is 0.5%-1.5%, such as 0.7%, 1% or 1.2%; preferably, the mass percentage of graphene powder is 3%, and the mass percentage of dispersant is 1%; under this ratio, the graphene dispersion effect is better.

[0029] In some specific examples, the above preparation method satisfies one or more of the following conditions:

[0030] (i) In step (1), ultrasound is used to assist in the mixing process; specifically, when dispersing the graphene powder in the present invention, ultrasound can be used to assist in enhancing the dispersion effect; the frequency of the ultrasound can be 15kHz-25kHz, such as 17kHz, 20kHz or 22kHz;

[0031] (ii) In step (2), the pressing pressure is 2000 N / cm 2-2500N / cm 2 Specifically, the pressing pressure can be 2100N / cm 2 , 2200N / cm 2 or 2400N / cm 2 etc.; the pressing time is generally 1min-10min, such as 3min, 5min or 7min, etc.;

[0032] (iii) in step (3), the sintering temperature is 650°C-750°C, such as 680°C, 700°C or 720°C;

[0033] (iv) In step (3), the temperature of the solution treatment is 550°C-650°C, such as 570°C, 600°C or 620°C.

[0034] The embodiment of the present invention further provides a magnesium alloy prefabricated plate, which is prepared from the graphene-reinforced magnesium alloy of the present invention.

[0035] It should be noted that in the present invention, the graphene-enhanced magnesium alloy can also be prepared into a magnesium alloy prefabricated plate, which is more convenient for use; in addition, the shape or specification of the prefabricated plate can be set according to specific needs; in addition, the preparation method of the prefabricated plate is well known in the art.

[0036] In order to better understand the present invention, the content of the present invention is further explained below in conjunction with specific examples, but the content of the present invention is not limited to the following examples.

[0037] 1. Preparation of graphene-enhanced magnesium alloy

[0038] Example 1

[0039] (1) Graphene dispersion treatment: 30 g of graphene powder and 10 g of sodium polyacrylate were weighed, water was added to 1000 g, and then ultrasonic (20 kHz) oscillation was performed for 30 min to obtain a graphene suspension.

[0040] (2) Surface treatment of magnesium alloy powder: 905 g of magnesium powder, 50 g of aluminum powder, 30 g of zinc powder and 15 g of manganese powder were weighed and treated with acid (15% by mass sulfuric acid) to remove oxides and other impurities on their surfaces; then they were washed with deionized water, dried and mixed to obtain alloy powder.

[0041] (3) Mixing and pressing: Mix the graphene suspension and alloy powder, and stir to make the graphene evenly distributed in the mixture; then pour the mixture into the mold and press at 2200N / cm 2 The composite material blank was obtained by pressing at a pressure of 3 minutes and performing degassing during the pressing process.

[0042] (4) Sintering and solution treatment: The composite material blank was sintered at 700°C for 5 hours in a nitrogen environment; then, the blank was kept at 600°C for 2 hours for solution treatment to obtain a graphene-reinforced magnesium alloy.

[0043] Example 2

[0044] The difference between Example 2 and Example 1 is that the masses of magnesium powder, aluminum powder, zinc powder and manganese powder in the alloy powder are different. The magnesium powder, aluminum powder, zinc powder and manganese powder in Example 2 are 916g of magnesium powder, 47g of aluminum powder, 27g of zinc powder and 10g of manganese powder respectively; the rest is the same as Example 1, and a graphene-enhanced magnesium alloy is prepared.

[0045] Example 3

[0046] The difference between Example 3 and Example 1 is that the masses of magnesium powder, aluminum powder, zinc powder and manganese powder in the alloy powder are different. The magnesium powder, aluminum powder, zinc powder and manganese powder in Example 3 are 892g of magnesium powder, 55g of aluminum powder, 33g of zinc powder and 20g of manganese powder respectively; the rest is the same as Example 1, and a graphene-enhanced magnesium alloy is prepared.

[0047] Example 4

[0048] The difference between Example 4 and Example 1 is that the amount of graphene powder added is different. The mass of the graphene powder in Example 4 is 10 g. The rest is the same as Example 1, and a graphene-reinforced magnesium alloy is prepared.

[0049] Example 5

[0050] The difference between Example 5 and Example 1 is that the amount of graphene powder added is different. The mass of the graphene powder in Example 5 is 45 g. The rest is the same as Example 1, and a graphene-reinforced magnesium alloy is prepared.

[0051] Example 6

[0052] The difference between Example 6 and Example 1 is that the added amount of sodium polyacrylate is different. The mass of sodium polyacrylate in Example 6 is 5 g. The other conditions are the same as Example 1, and a graphene-reinforced magnesium alloy is prepared.

[0053] Example 7

[0054] The difference between Example 7 and Example 1 is that the added amount of sodium polyacrylate is different. The mass of sodium polyacrylate in Example 7 is 15 g. The other conditions are the same as Example 1, and a graphene-reinforced magnesium alloy is prepared.

[0055] Example 8

[0056] The difference between Example 8 and Example 1 is that potassium polyacrylate is used to replace sodium polyacrylate, and the other steps are the same as Example 1 to prepare a graphene-reinforced magnesium alloy.

[0057] Example 9

[0058] The difference between Example 9 and Example 1 is that polyvinyl alcohol is used to replace sodium polyacrylate, and the other steps are the same as Example 1 to prepare a graphene-reinforced magnesium alloy.

[0059] Example 10

[0060] The difference between Example 10 and Example 1 is that polyethylene glycol is used to replace sodium polyacrylate, and the other steps are the same as Example 1 to prepare a graphene-reinforced magnesium alloy.

[0061] Comparative Example 1

[0062] The difference between Comparative Example 1 and Example 1 is that Comparative Example 1 does not include step (1) (ie, graphene and sodium polyacrylate are not added), and the rest is the same as Example 1 to prepare a graphene-reinforced magnesium alloy.

[0063] 2. Performance test of graphene-enhanced magnesium alloy

[0064] The graphene-reinforced magnesium alloys prepared in Examples 1 to 10 and Comparative Example 1 were tested for tensile strength according to the "GB / T228.1-2021" standard, for Brinell hardness according to the "GB / T231.1-2018" standard, for toughness according to the "GB / T229-2020" standard, and for elongation according to the "GB / T228.1-2021" standard; the test results are shown in Table 1 below.

[0065] Table 1 Properties of graphene-enhanced magnesium alloys prepared in Examples / Comparative Examples

[0066]

[0067] It can be seen from Table 1 above that the tensile strength and hardness of the magnesium alloy treated with graphene are improved compared with the untreated magnesium alloy (Comparative Example 1), among which, the improvement effect of Examples 1 to 8 is better than that of Examples 9 and 10, that is, different dispersants are used in the present invention, and the effects are different; in addition, the toughness and elongation of the alloys of Examples 1 to 10 are not significantly changed compared with Comparative Example 1, indicating that Examples 1 to 10 improve the tensile strength and hardness while maintaining excellent toughness and elongation, among which Example 1 has the best effect, and the tensile strength of Example 1 is improved by about 32% compared with Comparative Document 1, and the hardness is improved by about 22.9%.

[0068] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be covered by the scope of the claims of the present invention.

Claims

1. A graphene-enhanced magnesium alloy, characterized in that: It comprises graphene and alloy; wherein, the elements in the alloy include 4.7%-5.5% aluminum, 2.7%-3.3% zinc, 1%-2% manganese and the remainder magnesium and inevitable impurities according to mass fraction; the added amount of graphene is 1%-4.5% of the alloy mass.

2. The graphene-enhanced magnesium alloy according to claim 1, characterized in that: The graphene enhanced magnesium alloy meets one or more of the following conditions: (a) The elements in the alloy, by mass percentage, include 5% aluminum, 3% zinc, 1.5% manganese and the balance magnesium and unavoidable impurities; (b) The addition amount of graphene is 3% of the alloy mass.

3. The method for preparing a graphene-enhanced magnesium alloy according to claim 1 or 2, characterized in that: include: (1) mixing graphene powder, a dispersant and water to obtain a graphene suspension; (2) mixing the graphene suspension and alloy powder, and pressing to obtain a composite material blank; (3) The composite material blank is sintered and solution treated to obtain graphene-reinforced magnesium alloy.

4. The method for preparing a graphene-enhanced magnesium alloy according to claim 3, characterized in that: The dispersant is selected from one or more of sodium polyacrylate, potassium polyacrylate, polyvinyl alcohol or polyethylene glycol.

5. The method for preparing a graphene-enhanced magnesium alloy according to claim 4, characterized in that: In the graphene suspension, the mass percentage of graphene powder is 1%-4.5%, and the mass percentage of dispersant is 0.5%-1.5%.

6. The preparation method according to claim 5, characterized in that: The mass percentage of graphene powder is 3%, and the mass percentage of dispersant is 1%.

7. The preparation method according to any one of claims 3 to 6, characterized in that: The preparation method meets one or more of the following conditions: (i) in step (1), ultrasound is used to assist the mixing process; (ii) In step (2), the pressing pressure is 2000 N / cm 2 -2500N / cm 2 ; (iii) in step (3), the sintering temperature is 650° C.-750° C.; (iv) In step (3), the temperature of the solution treatment is 550°C-650°C.

8. The preparation method according to claim 7, characterized in that: The frequency of ultrasound is 15kHz-25kHz.

9. A magnesium alloy prefabricated plate, characterized in that: It is prepared from the graphene-reinforced magnesium alloy according to claim 1 or 2.

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