A method for preparing an aluminum bronze matrix composite by remelting dilution and an aluminum bronze matrix composite

Abstract

The application provides a method for preparing an aluminum-bronze-based composite material by remelting dilution and the aluminum-bronze-based composite material, and the method comprises the following steps: putting an aluminum-based composite material into a copper melt to obtain the aluminum-bronze-based composite material. The mass ratio of the aluminum-based composite material to the copper melt is 2-8:98-92. The aluminum-based composite material comprises 2-10 wt% TiB2 particles and the balance of aluminum. Compared with the in-situ self-formation method in the copper melt, the method for preparing the aluminum-bronze-based composite material by remelting dilution can greatly reduce the agglomeration of the particles, so that the tensile strength and elongation of the prepared aluminum-bronze-based composite material are significantly improved. In addition, the application simplifies the smelting process, has the advantages of energy saving, high efficiency, green and no pollution.

Description

Technical Field

[0001] This invention relates to aluminum bronze matrix composite technology, and more particularly to a method for preparing aluminum bronze matrix composites by remelting and dilution, and the aluminum bronze matrix composites thereof. Background Technology

[0002] Copper and its alloys possess excellent electrical and thermal conductivity, as well as corrosion resistance, playing a vital role in modern industry. However, copper's low yield strength and poor wear resistance limit the further application of copper alloys. Alloying methods induce lattice distortion or age-induced precipitation strengthening in the aluminum bronze matrix, improving the properties of copper alloys. However, copper alloys lack load-bearing particles, resulting in poor wear resistance, and high temperatures can cause the precipitated phase to dissolve, leading to material failure. Aluminum bronze matrix composites can retain the electrical and thermal conductivity of copper alloys while improving the material's mechanical and tribological properties. Because copper in aluminum bronze matrix composites has poor wettability and bonding with most particles, fracture occurs at the particle level. Therefore, the ideal state for aluminum bronze matrix composites is a fine and dispersed second phase distributed throughout the matrix.

[0003] Aluminum bronze matrix composites are typically prepared by adding a second phase, usually ceramic particles, to pure copper or copper alloys. Preparation methods for aluminum bronze matrix composites include self-propagating high-temperature synthesis, spray deposition, and mechanical alloying. These newer methods have addressed the agglomeration problem in aluminum bronze matrix composites to some extent, but their high energy consumption and low efficiency are significant limitations. Therefore, casting remains a method we are researching for improvement. In-situ self-generation is a common method for introducing second-phase particles during casting. Particles prepared by this method have good wettability with the matrix, but due to the high temperature of the copper melt, the particle agglomerates are relatively large. Particle agglomeration deteriorates the composite material's properties and reduces its wear resistance. Therefore, a new preparation process is needed to improve the particle agglomeration problem in composite materials. Summary of the Invention

[0004] The purpose of this invention is to address the problem that traditional methods for preparing aluminum bronze matrix composites result in large particle agglomerates, leading to deterioration in composite material performance. This invention proposes a remelting and dilution method for preparing aluminum bronze matrix composites. Compared to the in-situ self-generation method in molten copper, this method significantly reduces particle agglomeration, thus resulting in a substantial improvement in the tensile strength and elongation of the prepared aluminum bronze matrix composite. Furthermore, this invention simplifies the smelting process and offers advantages such as energy efficiency, high performance, and environmental friendliness.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is: a method for preparing aluminum bronze-based composite materials by remelting and dilution, comprising the following steps:

[0006] Aluminum bronze-based composite materials were prepared by adding aluminum-based composite materials into copper melt.

[0007] Furthermore, aluminum-based composite materials are added to the copper melt and kept at a certain temperature for a certain period of time; after cooling, aluminum bronze-based composite materials are prepared by casting.

[0008] Furthermore, the mass ratio of the aluminum-based composite material to the copper melt is 2-8:98-92, preferably 4-6:96-94.

[0009] Furthermore, the temperature of the copper melt during the addition of the aluminum-based composite material is 1220℃~1280℃.

[0010] Furthermore, the aluminum-based composite material is dried before melting at a temperature of 250℃ to 350℃ for a time of 30 min to 90 min.

[0011] Furthermore, the heat preservation time is 10-20 minutes.

[0012] Furthermore, the cooling method is circulating water cooling, and the temperature of the circulating water is room temperature.

[0013] Furthermore, the casting temperature is 1180℃~1220℃.

[0014] Furthermore, the method for preparing the copper melt includes the following steps: electrolytic copper smelting and refining.

[0015] Furthermore, the purity of the electrolytic copper is ≥99.97%.

[0016] Furthermore, the electrolytic copper smelting temperature is 1200℃~1300℃.

[0017] Furthermore, the atmosphere for the electrolytic copper smelting is a vacuum filled with argon gas.

[0018] Furthermore, the refining temperature is 1240℃~1260℃, and the refining time is 5min~15min.

[0019] Furthermore, the aluminum-based composite material is an aluminum-based TiB2 particle composite material.

[0020] Furthermore, the aluminum-based composite material comprises 2-10 wt% TiB2 particles and the balance aluminum.

[0021] Furthermore, the preparation method of the aluminum-based composite material includes the following steps:

[0022] K2TiF6 and KBF4 were mixed with a Ti:B stoichiometric ratio of 1:2, and the mixture was preheated at 250-350℃ for 1-3 hours to remove moisture, thus obtaining a mixed fluoride salt.

[0023] At 800-900℃, mixed fluoride salts are added to the Al melt, held at this temperature for 20-60 minutes, slag is removed, the mixture is stirred, refined and degassed, and then cast to obtain an aluminum-based composite material.

[0024] Furthermore, the Al is of commercial purity, 99.85%.

[0025] Furthermore, the K2TiF6 has an analytical purity of 99%.

[0026] Furthermore, the KBF4 is of analytical purity, 99%.

[0027] Another object of the present invention discloses an aluminum bronze-based composite material prepared by the above method.

[0028] Furthermore, the aluminum bronze-based composite material comprises 2-8 wt% aluminum-based composite material, with the balance being Cu and unavoidable impurities.

[0029] Furthermore, the aluminum bronze-based composite material comprises 4-6 wt% aluminum-based composite material, with the balance being Cu and unavoidable impurities.

[0030] Furthermore, the aluminum bronze matrix composite material has a microhardness of 200~220Hv, a tensile strength of 750~770MPa, a yield strength of 615~635MPa, and an elongation of 7.5~8.5%.

[0031] Furthermore, the size of the TiB2 particles in the aluminum bronze matrix composite material is 0.55±0.05μm.

[0032] The method for preparing aluminum bronze matrix composites by remelting and dilution according to the present invention, and the aluminum bronze matrix composites thereof, have the following advantages compared with the prior art:

[0033] This invention provides a method for preparing aluminum bronze-based composite materials using a remelting and dilution method, comprising: smelting and refining electrolytic copper to obtain a copper melt; and adding an aluminum-based composite material to the melt to obtain the aluminum bronze-based composite material. The aluminum-based composite material consists of 2-10% TiB2 particles by mass and the balance being aluminum. The remelting and dilution method provided by this invention can transfer the particle generation environment from the high-temperature copper melt to the lower-temperature aluminum melt. The particles generated in the aluminum melt have good wettability with the aluminum matrix and are smaller in diameter and more uniformly distributed. This aluminum-based composite material is added to the copper melt and diffuses to a uniform state over a period of time. According to dislocation theory, when the second phase is uniformly distributed in the matrix as fine, dispersed particles, dislocations interact with the hard particles of the second phase. When dislocations encounter the hard particles of the second phase, they are pinned, piled up, and subjected to various resistances, resulting in smaller particle size and increased tensile strength of the material. Compared with the in-situ self-generation method in the copper melt, this invention can significantly reduce particle agglomeration. In addition, this invention simplifies the smelting process, is energy-efficient, and environmentally friendly.

[0034] The aluminum bronze matrix composite material prepared by the remelting and dilution method of this invention has a microhardness of 211Hv, a tensile strength of 764.2MPa, a yield strength of 625.8MPa, and an elongation of 8.0%. Attached Figure Description

[0035] Figure 1 This is a comparison diagram of the microhardness of the aluminum bronze-based composite materials in Example 1 and Comparative Example 1 of the present invention.

[0036] Figure 2 The tensile stress-strain curves of the aluminum bronze matrix composite material in Example 1 and Comparative Example 1 of this invention are shown.

[0037] Figure 3 This is a scanning electron microscope image of the aluminum bronze-based composite material in Example 1 of the present invention.

[0038] Figure 4 This is a scanning electron microscope image of the aluminum bronze-based composite material in Comparative Example 1 of the present invention.

[0039] Figure 5 This is a particle size distribution diagram of TiB2 particles in the aluminum bronze matrix composite material of Example 1 of the present invention.

[0040] Figure 6 The particle size distribution of TiB2 particles in the aluminum bronze matrix composite material in Comparative Example 1 is shown. Detailed Implementation

[0041] The present invention will be further described below with reference to the embodiments:

[0042] This invention provides a method for preparing aluminum bronze-based composite materials by remelting and dilution, comprising:

[0043] Electrolytic copper is smelted and refined to obtain copper melt; an aluminum-based composite material is added to the melt to obtain an aluminum bronze-based composite material. The aluminum-based composite material consists of 2-10% TiB2 particles by mass and the balance being aluminum.

[0044] The remelting and dilution method provided by this invention can transfer the particle generation environment from the high-temperature copper melt to the lower-temperature aluminum melt. Particles generated in the aluminum melt exhibit good wettability with the aluminum matrix and have a smaller diameter and more uniform distribution. This aluminum-based composite material is added to the copper melt and diffuses to homogeneity over a period of time. According to dislocation theory, when the second phase is uniformly distributed in the matrix as fine, dispersed particles, dislocations interact with the hard particles of the second phase. When dislocations encounter the hard particles of the second phase, they are pinned, piled up, and subjected to various forms of resistance. The reduced particle size increases the tensile strength of the material. Compared with the in-situ self-generation method in the copper melt, this invention can significantly reduce particle agglomeration.

[0045] In this invention, the purity of the electrolytic copper is preferably ≥99.97%.

[0046] In this invention, the electrolytic copper is dried before smelting. The purpose of drying is to remove moisture from the surface of the electrolytic copper. The preferred drying temperature in this invention is 250℃~350℃, and the preferred drying time is 30min~90min.

[0047] In this invention, the preferred melting temperature is 1200℃~1300℃. The preferred refining temperature is 1240℃~1260℃, and the preferred refining time is 5min~15min. The refining process is to remove impurities from the copper and further improve the purity of the copper melt.

[0048] In this invention, the preferred smelting atmosphere is a vacuum filled with argon gas. By employing this atmosphere, the invention avoids the introduction of impurities from contact between the molten copper and air.

[0049] In this invention, the aluminum-based composite material is preferably composed of 2-10% TiB2 particles by mass and the balance being aluminum.

[0050] In this invention, the aluminum-based composite material is dried before melting. The purpose of drying is to remove moisture from the surface of the electrolytic copper. The preferred drying temperature in this invention is 250℃~350℃, and the preferred drying time is 30min~90min.

[0051] In this invention, the preferred temperature for adding the aluminum-based composite material is 1220℃~1280℃.

[0052] In this invention, the heat preservation time after the aluminum-based composite material is added is preferably 10-20 minutes. By controlling the heat preservation time within the above range, this invention can ensure that the aluminum-based composite material diffuses uniformly into the copper melt.

[0053] In this invention, the preferred casting temperature is 1180℃~1220℃. By controlling the casting temperature within this range, this invention ensures that particles do not agglomerate excessively during the casting process.

[0054] In this invention, the casting mold is preferably a cast iron mold. By selecting a cast iron mold for casting, this invention enables the aluminum bronze-based composite material melt to dissipate heat rapidly and solidify at a relatively fast rate.

[0055] In this invention, the cooling method is circulating water cooling, and the temperature of the circulating water cooling is room temperature.

[0056] The aluminum bronze matrix composite material prepared by the remelting and dilution method provided by this invention exhibits excellent mechanical properties. Furthermore, this invention significantly reduces particle agglomeration compared to the in-situ self-generation method. In addition, this invention simplifies the smelting process, is energy-efficient, and is environmentally friendly and pollution-free.

[0057] The present invention also provides an aluminum bronze-based composite material prepared by the method described above.

[0058] In this invention, the aluminum bronze matrix composite material preferably comprises 2-8% aluminum matrix composite material and the balance copper by mass percentage. The aluminum matrix composite material preferably comprises 2-10% TiB2 particles and the balance aluminum by mass percentage. This invention significantly improves the mechanical properties of the material by alloying the aluminum bronze matrix with the addition of the aluminum matrix composite material and the addition of a second phase.

[0059] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments thereof. The described embodiments are only some examples of the present invention, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the protection scope of the present invention. Example 1

[0060] This embodiment discloses a method for preparing an aluminum bronze-based composite material, specifically: aluminum-based composite material is sequentially added to a copper alloy liquid, and then cast to obtain the aluminum bronze-based composite material; the specific process is as follows:

[0061] (1) Perform two vacuuming operations in the vacuum intermediate frequency furnace and fill it with argon as a protective gas to reduce air contamination of the metal. Place the prepared electrolytic copper block (drying temperature 300℃, drying time 1h) into the crucible, heat it up, and control the melt temperature to about 1250℃. Control the temperature of the melt in the intermediate frequency furnace at 1250℃ and maintain it for 10min.

[0062] (2) The aluminum-based composite material (TiB2 particle content of 6%) was directly added into the refined copper melt and kept at the temperature for 10 minutes.

[0063] By adjusting the frequency, the temperature of the melt is reduced to 1200℃. The heating power of the medium frequency furnace is turned off, and the melt is poured into a steel mold and cooled in the furnace. Once cooled to room temperature, the aluminum bronze-based composite material ingot is removed.

[0064] The aluminum bronze-based composite material prepared by adding aluminum-based composite material to copper melt, by mass percentage, consists of 5.64% aluminum, 0.36% TiB2 particles and the balance copper.

[0065] Comparative Example 1

[0066] The remelting and dilution method with added particles in Example 1 was replaced with the in-situ self-generation method.

[0067] The in-situ self-generating method requires the preparation of an intermediate alloy, which is then sequentially added to molten copper and cast to obtain an aluminum bronze-based composite material. The following two processes are different from those in Example 1, while the remaining technical features are the same as in Example 1.

[0068] (1) Intermediate alloy smelting: The vacuum high-frequency furnace is subjected to two vacuum treatments, and argon is used as the protective gas. This reduces the air in the furnace and prevents the alloy from being contaminated by the air. Cu-B and Cu-Ti intermediate alloys are smelted at around 1300℃.

[0069] (2) Feeding: After the Cu-B master alloy wrapped in copper foil is put into the melt and kept for 5 minutes, the Cu-Ti master alloy is put into the melt and kept for 10 minutes after it has fully reacted.

[0070] The cast aluminum bronze matrix composites prepared in Example 1 and Comparative Example 1 were subjected to hardness testing using a Vickers hardness tester, and the microhardness test results are as follows: Figure 1 As shown.

[0071] The rolled aluminum bronze matrix composites prepared in Example 1 and Comparative Example 1 were subjected to tensile tests, and the resulting stress-strain curves are shown in the figure. Figure 2 As shown.

[0072] The TiB2 particle distribution of the cast aluminum bronze matrix composites prepared in Example 1 and Comparative Example 1 was observed under a scanning electron microscope, and the scanning images are shown below. Figure 3 and Figure 4 As shown.

[0073] The as-cast aluminum bronze matrix composites prepared in Example 1 and Comparative Example 1 were subjected to TiB2 particle size analysis (at least 1000 TiB2 particles were counted), and the particle size distribution diagrams are shown below. Figure 5 and Figure 6 As shown.

[0074] Depend on Figures 1-2 It can be seen that the aluminum bronze matrix composite material prepared by the remelting and dilution method in Example 1 of this invention has a microhardness of 211 Hv, a tensile strength of 764.2 MPa, a yield strength of 625.8 MPa, and an elongation of 8.0%. The aluminum bronze matrix composite material prepared in situ in Comparative Example 1 has a microhardness of 205 Hv, a tensile strength of 738.7 MPa, a yield strength of 545.9 MPa, and an elongation of 7.1%. The microhardness of the aluminum bronze matrix composite material in Comparative Example 1 is not significantly different from that in Example 1, but the tensile strength is increased by 25.5 MPa, the yield strength by 79.9 MPa, and the elongation by 0.9%.

[0075] Compared to the in-situ self-generation method in Comparative Example 1, the TiB2 particles in Example 1, produced by the remelting and dilution method, showed significantly smaller size and more uniform distribution. According to dislocation theory, when the second phase is uniformly distributed in the matrix as fine, dispersed particles, dislocations interact with the hard particles of the second phase. When dislocations encounter these hard particles, they are subjected to various forms of resistance, such as pinning and pile-up. Reducing particle size increases the tensile strength of the material. However, larger ceramic particles are more likely to contain defects, and fracture is more likely to occur at larger particles, thus exhibiting lower plasticity with larger particle sizes.

[0076] Depend on Figure 5 and Figure 6 It can be seen that the average particle size of Example 1 is 1.13 μm, and the average particle size of Comparative Example 1 is 0.58 μm. The size of the particle agglomerates was reduced by 0.55 μm (48.6%).

[0077] Comparative Example 1, using an in-situ self-generated aluminum bronze matrix composite material, exhibited a microhardness of 205 Hv, a tensile strength of 738.7 MPa, a yield strength of 545.9 MPa, and an elongation of 7.1%. Compared to Example 1, the aluminum bronze matrix composite material in Comparative Example 1 showed little change in microhardness, but its tensile strength increased by 25.5 MPa (3.4%), its yield strength by 79.9 MPa (14.6%), and its elongation increased by 0.9% (12.6%). Compared to the in-situ self-generated method in Comparative Example 1, the remelting and dilution method employed in this invention resulted in a significantly smaller and more uniformly distributed TiB2 particle size. The average particle size in Example 1 was 1.13 μm, while the average particle size in Comparative Example 1 was 0.58 μm. The size of the particle agglomerates decreased by 0.55 μm (48.6%).

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method of remelt dilution producing an aluminum bronze based composite material, characterized by, Prepared by the following steps: The preparation of copper melt includes the following steps: electrolytic copper smelting and refining; the electrolytic copper smelting temperature is 1200℃~1300℃; the atmosphere of electrolytic copper smelting is vacuum filled with argon gas; the refining temperature is 1240℃~1260℃, and the refining time is 5min~15min; The preparation method of aluminum-based composite material includes the following steps: K2TiF6 and KBF4 are mixed at a Ti:B stoichiometric ratio of 1:2, preheated at 250-350℃ for 1-3 hours to remove moisture, and mixed fluoride salt is obtained; at 800-900℃, the mixed fluoride salt is slowly added to Al melt, held at 20-60 min, slag is removed, stirred, refined and degassed, and cast to obtain aluminum-based composite material; An aluminum-based composite material is added to molten copper and kept at a certain temperature. After cooling, it is cast to prepare an aluminum bronze-based composite material, wherein the aluminum-based composite material is an aluminum-based TiB2 particle composite material; the aluminum-based composite material includes 2~10 wt% TiB2 particles and the balance aluminum. The mass ratio of the aluminum-based composite material to the copper melt is 2-8:98-92; The temperature of the copper melt during the addition of the aluminum-based composite material is 1220℃~1280℃; The heat preservation time is 10-20 minutes; The casting temperature is 1180℃~1220℃.

2. An aluminium bronze based composite material, characterised in that, It is prepared by the method described in claim 1.

Images