A method for reinforcing copper matrix composites based on MAX phase

Abstract

A method for reinforcing copper-based composite materials based on the MAX phase includes the following steps: (1) powder pretreatment; (2) high-temperature reduction; and (3) spark plasma sintering. This invention incorporates the MAX phase Ti4AlN3, which enhances the mechanical properties of copper-based alloys due to its high elastic modulus, good high-temperature plasticity, and thermal shock resistance. Traditional ball milling easily generates a large amount of heat, and the relatively soft copper material causes copper powder to agglomerate, resulting in a large particle size. This invention replaces the powder with a suspension, transferring the heat generated during ball milling by adding ethanol and isolating it from air. Sodium dodecylbenzoate is used as a dispersant, reducing the powder's agglomeration ability and accelerating the ball milling process. The combined effect of plasma activation and sintering densification refines the grain size of the alloy, ultimately producing a dense Cu-Ti4AlN3 composite material with superior mechanical properties and wider applications.

Description

Technical Field

[0001] This invention belongs to the field of copper-based tensile materials technology, specifically relating to a method for copper-based composite materials reinforced with MAX phase. Background Technology

[0002] Copper-based alloys are widely used in various electronic components due to their excellent electrical properties, but their poor mechanical properties limit their application in many emerging fields. In order to meet the high-performance requirements brought about by the progress of the times, it is necessary to further improve the comprehensive mechanical properties of copper alloys.

[0003] MAX phase is a novel type of ternary layered ceramic material with the chemical formula M n + 1 AX n With n = 1, 2, or 3, MAX phase materials combine the advantages of metals and ceramics, exhibiting excellent thermal conductivity, electrical conductivity, and thermal shock resistance. They maintain plasticity at high temperatures and can be processed like metals and graphite. Furthermore, they possess high yield strength, high melting point, high thermal stability, and excellent oxidation and corrosion resistance. Ti4AlN3 possesses a series of superior properties of MAX phases, such as high elastic modulus, good high-temperature plasticity, and thermal shock resistance; therefore, using Ti4AlN3 to strengthen a copper matrix is ​​a promising approach.

[0004] Currently, the commonly used methods for preparing MAX phase-reinforced copper matrices include powder metallurgy, spark plasma sintering, and hot pressing sintering. However, these methods have some problems, such as poor wettability between the MAX phase and the copper matrix, resulting in low bonding strength at the interface and easy cracking at the interface under stress; as well as insufficient material density, increased porosity, or grain growth in the copper matrix. Summary of the Invention

[0005] The purpose of this invention is to provide a method for reinforcing copper-based composite materials based on the MAX phase, which significantly improves the mechanical properties of the prepared Cu-Ti4AlN3 composite material.

[0006] To achieve the above objectives, the present invention employs the following technical solutions:

[0007] A method for reinforcing copper-based composite materials based on MAX phases specifically includes the following steps:

[0008] (1) Powder pretreatment

[0009] Weigh out high-purity Cu powder and Ti4AlN3 powder respectively and add them to beakers in sequence. Add anhydrous ethanol until the powder is completely submerged. Then add dispersant. Place the beaker in a magnetic stirrer and heat and stir. After stirring thoroughly, add anhydrous ethanol again until the powder is submerged. Put the slurry into a ball mill jar, add hard alloy balls. After assembly, fix the ball mill jar in a planetary ball mill for ball milling.

[0010] (2) High-temperature reduction

[0011] Take out the slurry after ball milling in step (1) and place it in a beaker. Place the beaker in a drying oven to dry it. Grind the dried powder evenly and spread it on a ceramic firing boat. Then place it in a tube furnace. Set the program and carry out reduction treatment in a hydrogen atmosphere to finally obtain Cu-Ti4AlN3 composite powder.

[0012] (3) Spark plasma sintering

[0013] The Cu-Ti4AlN3 composite powder that has been reduced in step (2) is ground and added to a graphite mold. The graphite mold is placed in the furnace cavity of a spark plasma sintering furnace for pre-compactment. After setting the program, the furnace cavity is vacuum treated and then sintered. After sintering, Cu-Ti4AlN3 composite material is obtained.

[0014] In step (1), the mass fraction of Ti4AlN3 powder is 0.5-1.0%, and the remainder is high-purity Cu powder. The Cu powder is high-purity electrolytic Cu powder, which is grape-like in shape, with a purity of 99.999% and a particle size of 1-3μm. The purity of Ti4AlN3 powder is 98%, and the particle size is 700-800 mesh.

[0015] In step (1), the magnetic stirrer is a DF-101S type heat-collecting magnetic stirrer with a stirring temperature of 25-35℃ and a stirring time of 6-8 h. In addition to an appropriate amount of anhydrous ethanol, sodium dodecyl benzoate is added to the beaker as a dispersant. The amount added depends on the dispersion of the mixed powder to promote more uniform powder dispersion.

[0016] In step (1), the planetary ball mill is the Nanjing University Instruments QM-QX4 omnidirectional planetary ball mill with a ball milling speed (rotation speed) of 600 rpm, a ball-to-material ratio of 5:1, a ball milling time of 4 h, and the ball tank and the ball milling media balls are all made of hard alloy.

[0017] In step (2), the slurry after ball milling is taken out and placed in a beaker. The slurry residue on the ball milling tank wall and the surface of the alloy balls is repeatedly rinsed with anhydrous ethanol and then placed in a drying oven. The model of the drying oven is DHG-9000-9005, the drying temperature is 50-60 ℃, and the drying time is 12 h.

[0018] In step (2), the high-temperature tubular furnace is model GSL-1200X, and the program is set as follows: the temperature is increased from room temperature to 600 ℃ at 10 ℃ / min, held for 2 h, and then decreased to 500 ℃ at 10 ℃ / min, and then cooled to room temperature with the furnace.

[0019] The gas introduced in step (2) is 10% H2-90% Ar, and the introduction rate is 300-350 ml / min.

[0020] In step (3), the inner diameter of the graphite mold is 20 mm, the outer diameter is 60 mm, and the height is 70 mm. Carbon paper is used to separate the Cu-Ti4AlN3 composite powder from the graphite mold to facilitate sampling and demolding after sintering.

[0021] In step (3), the discharge plasma sintering furnace is model LaboxTM-300, and thermocouple temperature measurement is used. The front end of the thermocouple is inserted into the temperature measuring hole of the graphite mold.

[0022] The discharge plasma sintering program in step (3) is as follows: the temperature is raised from room temperature to 550-600 ℃ and held for 5 min, then the temperature is raised to 850-900 ℃ and held for 5 min. The heating rate is 80-100 ℃ / min, the pre-pressure is 10 MPa, and the pressure is raised to 50 MPa during the second heating process. After holding for 5 min, the temperature is cooled with the furnace.

[0023] The innovation of this invention lies in:

[0024] In terms of material design: Cu powder and Ti4AlN3 powder are mixed in a certain proportion, and the high elastic modulus, good high-temperature plasticity and thermal shock resistance of Ti4AlN3 are fully utilized to achieve the reinforcement effect on the copper matrix.

[0025] Regarding the preparation method: The preparation method of the present invention consists of wet dispersion, ball milling, drying, reduction and spark plasma sintering processes, which gives the material a specific crystal structure and phase composition, thereby improving the material's performance. This preparation method makes it possible to mass-produce this high-performance electrical contact material.

[0026] In terms of performance optimization: by reinforcing copper-based composite materials with Ti4AlN3, the mechanical properties of copper-based alloys are further improved while maintaining excellent electrical conductivity, exhibiting excellent overall performance.

[0027] Compared with existing technologies, the present invention has at least the following advantages:

[0028] This invention incorporates the MAX phase Ti4AlN3, which enhances the mechanical properties of copper-based alloys due to its high elastic modulus, good high-temperature plasticity, and thermal shock resistance. Traditional ball milling easily generates a large amount of heat, and because copper is relatively soft, copper powder tends to agglomerate, resulting in large particle sizes. This invention replaces powder with a suspension, using ethanol to transfer the heat generated during ball milling and isolating it from air. Sodium dodecylbenzoate is used as a dispersant to reduce powder agglomeration and accelerate the ball milling process. Spark plasma sintering technology refines the grain size of the alloy through the combined effects of plasma activation and sintering densification, ultimately producing a dense Cu-Ti4AlN3 composite material with superior mechanical properties and wider applications. Attached Figure Description

[0029] Figure 1 This is a surface morphology diagram of the raw material, high-purity copper powder.

[0030] Figure 2 High-magnification morphology of the fracture surface of Cu-1.0%Ti4AlN3 composite material;

[0031] Figure 3 High-magnification morphology of the fracture surface of Cu-0.5%Ti4AlN3 composite material;

[0032] Figure 4 EDS analysis chromatogram of Cu-1.0%Ti4AlN3 composite material;

[0033] Figure 5 EDS analysis results for Cu-0.5%Ti4AlN3 composite material. Detailed Implementation

[0034] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0035] Example 1

[0036] The Cu-Ti4AlN3 composite material in this embodiment is processed by wet dispersion, ball milling, drying, reduction and spark plasma sintering. The mass fraction of Ti4AlN3 is 1.0%, and the remainder is high-purity electrolytic Cu powder in the form of grape bunches with a purity of 99.999% and a particle size of 1-3 μm. The purity of Ti4AlN3 powder is 98% and the particle size is 700-800 mesh.

[0037] The preparation method of Cu-Ti4AlN3 composite material in this embodiment is as follows:

[0038] (1) Powder pretreatment

[0039] Weigh out 49.5g of high-purity Cu powder and 0.5g of Ti4AlN3 powder, add them to a beaker, add anhydrous ethanol until the powder is completely submerged, then add 0.06g of sodium dodecylbenzoate. Place the beaker in a magnetic stirrer and stir at 25-35 ℃ for 6-8 hours. After stirring thoroughly, add anhydrous ethanol again until the powder is submerged. Put the slurry into a ball mill jar, add cemented carbide balls at a ball-to-powder ratio of 5:1. After assembly, fix the ball mill jar in a planetary ball mill and ball mill for 4 hours.

[0040] (2) High-temperature reduction

[0041] The slurry after ball milling was taken out and placed in a beaker. The slurry residue on the ball mill jar wall and the surface of the alloy balls was repeatedly rinsed with anhydrous ethanol. The beaker was then placed in a drying oven for drying at 50-60 ℃ for 12 h. After drying, the obtained powder was ground and evenly spread on a ceramic sintering boat and placed in a tube furnace. A reducing atmosphere was created by passing 10% H2-90% Ar gas through the furnace at a flow rate of 300-350 ml / min. The program was set to raise the temperature from room temperature to 600 ℃ at 10 ℃ / min, hold for 2 h, and then lower the temperature to 500 ℃ at 10 ℃ / min. The furnace was then cooled to room temperature to obtain Cu-Ti4AlN3 composite powder.

[0042] (3) Spark plasma sintering

[0043] The reduced Cu-Ti4AlN3 composite powder was ground and added to a graphite mold (with an inner diameter of 20 mm, an outer diameter of 60 mm, and a height of 70 mm, and the Cu-Ti4AlN3 composite powder was separated from the graphite mold by carbon paper for easy sampling and demolding after sintering) wrapped in carbon paper. The graphite mold was then placed in the furnace cavity of a spark plasma sintering furnace and pre-compacted at a pressure of 10 MPa. The tip of a thermocouple was inserted into the temperature measuring hole of the graphite mold. The furnace door was closed for vacuum treatment. After the furnace cavity reached the vacuum level, sintering was carried out according to the set program as follows: the temperature was raised from room temperature to 550-600 ℃ and held for 5 min, then the temperature was raised to 850-900 ℃ and held for 5 min, with a heating rate of 80-100 ℃ / min. During this process, the pressure was raised to 50 MPa and held for 5 min. After cooling in the furnace, the Cu-Ti4AlN3 composite material was obtained.

[0044] Example 2

[0045] The Cu-Ti4AlN3 composite material in this embodiment is processed by wet dispersion, ball milling, drying, reduction and spark plasma sintering. The mass fraction of Ti4AlN3 is 1.0%, and the remainder is high-purity electrolytic Cu powder in the form of grape bunches with a purity of 99.999% and a particle size of 1-3 μm. The purity of Ti4AlN3 powder is 98% and the particle size is 700-800 mesh.

[0046] The preparation method of Cu-Ti4AlN3 composite material in this embodiment is as follows:

[0047] (1) Powder pretreatment

[0048] Weigh out 49.75g of high-purity Cu powder and 0.25g of Ti4AlN3 powder, add them to a beaker, add anhydrous ethanol until the powder is completely submerged, then add 0.06g of sodium dodecylbenzoate. Place the beaker in a magnetic stirrer and stir at 25-35 ℃ for 6-8 hours. After stirring thoroughly, add anhydrous ethanol again until the powder is submerged. Put the slurry into a ball mill jar, add cemented carbide balls at a ball-to-powder ratio of 5:1. After assembly, fix the ball mill jar in a planetary ball mill and ball mill for 4 hours.

[0049] (2) High-temperature reduction

[0050] The slurry after ball milling was taken out and placed in a beaker. The slurry residue on the surface of the ball milling jar and alloy balls was repeatedly rinsed with anhydrous ethanol. The beaker was then placed in a drying oven for drying at 50-60 ℃ for 12 h. After drying, the obtained powder was ground and evenly spread on a ceramic sintering boat and placed in a tube furnace. A reducing atmosphere was created by passing 10% H2-90% Ar gas at a flow rate of 300-350 ml / min. The program was set to raise the temperature from room temperature to 600 ℃ at 10 ℃ / min, hold for 2 h, and then lower the temperature to 500 ℃ at 10 ℃ / min. The furnace was then cooled to room temperature to obtain Cu-Ti4AlN3 composite powder.

[0051] (3) Spark plasma sintering

[0052] The reduced Cu-Ti4AlN3 composite powder was ground and added to a graphite mold (with an inner diameter of 20 mm, an outer diameter of 60 mm, and a height of 70 mm, and the Cu-Ti4AlN3 composite powder was separated from the graphite mold by carbon paper for easy sampling and demolding after sintering) wrapped in carbon paper. The graphite mold was then placed in the furnace cavity of a spark plasma sintering furnace and pre-compacted at a pressure of 10 MPa. The tip of a thermocouple was inserted into the temperature measuring hole of the graphite mold. The furnace door was closed for vacuum treatment. After the furnace cavity reached the vacuum level, sintering was carried out according to the set program as follows: the temperature was raised from room temperature to 550-600 ℃ and held for 5 min, then the temperature was raised to 850-900 ℃ and held for 5 min, with a heating rate of 80-100 ℃ / min. During this process, the pressure was raised to 50 MPa and held for 5 min. After cooling in the furnace, the Cu-Ti4AlN3 composite material was obtained.

[0053] Table 1 below shows Cu, Cu-1.0% Ti4AlN 3， Table of bulk mechanical properties of Cu-0.5%Ti4AlN3. Formed by spark plasma sintering, its tensile strength and hardness are significantly improved compared to pure copper.

[0054] Table 1. Performance of the Sample Block

[0055] from Figure 1 It can be seen that the copper powder is spherical with a particle size of 1-3μm. The powder agglomerates into grape-like clusters and has a smooth surface.

[0056] from Figure 2 , Figure 3 It can be seen that the Cu-1.0%Ti4AlN3 and Cu-0.5%Ti4AlN3 ports exhibit an overall morphology of equiaxed dimples with relatively uniform dimple distribution; at the same time, tearing ridges and some steps were found in the fracture, suggesting a mixed fracture dominated by ductile fracture.

[0057] from Figure 4 , Figure 5 As can be seen, various elemental additions can be found from the energy spectrum analysis.

[0058] This invention incorporates the MAX phase Ti4AlN3, introducing its high elastic modulus and good high-temperature plasticity, thereby enhancing the copper-based composite material and improving the mechanical properties of the copper alloy. Traditional ball milling easily generates a large amount of heat, and due to the softness of copper, copper powder tends to agglomerate, resulting in a large particle size. This invention uses a suspension instead of powder, transferring the heat generated during ball milling by adding ethanol and isolating it from air. Sodium dodecylbenzoate is used as a dispersant, reducing the powder's agglomeration ability and accelerating the ball milling process. Spark plasma sintering technology refines the alloy's grain size through the combined effects of plasma activation and sintering densification, ultimately producing a dense Cu-Ti4AlN3 composite material with superior mechanical properties and wider applications.

[0059] The above embodiments are merely illustrative of specific implementations of this disclosure, but the implementations of this disclosure are not limited to the above content. Any changes, modifications, substitutions, combinations, or simplifications made without substantially departing from the spirit and principle of the inventive concept of this disclosure shall be considered equivalent substitutions and included within the scope of protection defined by the claims.

Claims

1. A method for reinforcing copper-based composite materials based on MAX phase, characterized in that: Specifically, the following steps are included: (1) Powder pretreatment Weigh out high-purity Cu powder and Ti4AlN3 powder separately and add them to a beaker in sequence. Add anhydrous ethanol until the powder is completely submerged, then add a dispersant. Place the beaker in a magnetic stirrer and heat and stir. After stirring thoroughly, add anhydrous ethanol again until the powder is submerged. Put the slurry into a ball mill jar, add cemented carbide balls, and after assembly, fix the ball mill jar in a planetary ball mill for ball milling. The mass fraction of Ti4AlN3 powder is 0.5-1.0%, and the remainder is high-purity Cu powder. (2) High-temperature reduction Take out the slurry after ball milling in step (1) and place it in a beaker. Place the beaker in a drying oven to dry it. Grind the dried powder evenly and spread it on a ceramic firing boat. Then place it in a tube furnace. Set the program and carry out reduction treatment in a hydrogen atmosphere to finally obtain Cu-Ti4AlN3 composite powder. The gas introduced is 10% H2-90% Ar and the introduction rate is 300-350 ml / min. (3) Spark plasma sintering The Cu-Ti4AlN3 composite powder reduced in step (2) was ground and added to a graphite mold. The graphite mold was placed in the furnace cavity of a spark plasma sintering furnace for pre-compactment. After setting the program, the furnace cavity was vacuum treated and then sintered. After sintering, Cu-Ti4AlN3 composite material was obtained. The spark plasma sintering program was set as follows: the temperature was raised from room temperature to 550-600℃ and held for 5 min, then the temperature was raised to 850-900℃ and held for 5 min. The heating rate was 80-100℃ / min, the pre-compression pressure was 10 MPa, and the pressure was raised to 50 MPa during the second heating process. After holding for 5 min, the temperature was cooled with the furnace.

2. The method for a copper-based composite material based on MAX phase reinforcement as described in claim 1, characterized in that: In step (1), the Cu powder is high-purity electrolytic Cu powder, which is grape-like in shape, with a purity of 99.999% and a particle size of 1-3μm. The Ti4AlN3 powder has a purity of 98% and a particle size of 700-800 mesh.

3. The method for a copper-based composite material based on MAX phase reinforcement as described in claim 1, characterized in that: In step (1), the magnetic stirrer is a DF-101S type heat-collecting magnetic stirrer with a stirring temperature of 25-35 ℃ and a stirring time of 6-8 h. In addition to an appropriate amount of anhydrous ethanol, sodium dodecyl benzoate is added to the beaker as a dispersant. The amount added depends on the dispersion of the mixed powder to promote more uniform powder dispersion.

4. The method for a copper-based composite material based on MAX phase reinforcement as described in claim 1, characterized in that: In step (1), the planetary ball mill is the Nanjing University Instruments QM-QX4 omnidirectional planetary ball mill with a ball milling speed of 600 rpm, a ball-to-material ratio of 5:1, a ball milling time of 4 h, and the ball tank and the ball milling media balls are all made of hard alloy.

5. The method for a copper-based composite material based on MAX phase reinforcement as described in claim 1, characterized in that: In step (2), the slurry after ball milling is taken out and placed in a beaker. The slurry residue on the ball milling tank wall and the surface of the alloy balls is repeatedly rinsed with anhydrous ethanol and then placed in a drying oven. The model of the drying oven is DHG-9000-9005, the drying temperature is 50-60 ℃, and the drying time is 12 h.

6. The method for a copper matrix composite material based on MAX phase reinforcement as described in claim 1, characterized in that: In step (2), the tubular furnace model is GSL-1200X, and the program is set as follows: the temperature is increased from room temperature to 600 ℃ at 10 ℃ / min, held for 2 h, then decreased to 500 ℃ at 10 ℃ / min, and then cooled to room temperature with the furnace.

7. The method for a copper matrix composite material based on MAX phase reinforcement as described in claim 1, characterized in that: In step (3), the inner diameter of the graphite mold is 20 mm, the outer diameter is 60 mm, and the height is 70 mm. Carbon paper is used to separate the Cu-Ti4AlN3 composite powder from the graphite mold to facilitate sampling and demolding after sintering.

8. The method for a copper matrix composite material based on MAX phase reinforcement as described in claim 1, characterized in that: In step (3), the discharge plasma sintering furnace is model LaboxTM-300, and thermocouple temperature measurement is used. The front end of the thermocouple is inserted into the temperature measuring hole of the graphite mold.

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