A nanoparticle-reinforced 7075 aluminum alloy wire suitable for 3D printing and a preparation method thereof

Abstract

The present invention discloses a nanoparticle-reinforced 7075 aluminum alloy wire suitable for 3D printing and a preparation method thereof. The preparation method comprises the following steps: uniformly mixing 7075 aluminum alloy powder, nano-titanium carbide, and an inorganic salt to obtain a precursor powder A; heating and melting the precursor powder A, followed by ultrasonic dispersion treatment, to obtain a precursor powder B; placing the precursor powder B in water and stirring, allowing the suspension to precipitate, and pouring out the upper suspension to obtain a bottom mixed solution C; filtering and drying the bottom mixed solution C to obtain a nanoparticle-reinforced 7075 aluminum alloy composite powder; mixing the composite powder with 7075 aluminum alloy powder and performing powder metallurgy sintering to obtain a nanoparticle-reinforced 7075 aluminum alloy bulk material; heating the bulk material, placing it in an extruder, extruding it, and then annealing and drawing it to obtain a nanoparticle-reinforced 7075 aluminum alloy wire having a desired diameter and nanoparticle content. The preparation method proposed by the present invention has simple steps, good reproducibility, and can be used for industrial small- and medium-scale production.

Description

Technical Field

[0001] The present invention relates to the technical field of aluminum alloy wire preparation, and in particular to a nanoparticle-reinforced 7075 aluminum alloy wire suitable for 3D printing and a preparation method thereof. Background Art

[0002] 7075 aluminum alloy boasts excellent properties such as low density and high specific strength, and its products are widely used in aviation, aerospace, rail transportation, and other fields. However, some sectors are demanding further improvements in the complex formability and mechanical properties of 7075 aluminum alloy. Therefore, the combination of complex-shape 3D printing technology and 7075 aluminum alloy wire can perfectly meet these performance and complex configuration requirements, significantly expanding the application of 7075 aluminum alloy in complex-shaped components in related fields.

[0003] Ceramic particle-reinforced aluminum-matrix composites (AMCs) are a type of aluminum-based composite material obtained by adding dispersed ceramic particles as a reinforcement phase to an aluminum alloy matrix. The reinforcement phase exhibits high strength, high hardness, and a high melting point. Furthermore, because the reinforcement particles are dispersed throughout the metal matrix, their pinning action effectively reduces dislocation motion within the metal matrix, significantly improving the mechanical properties of the material. Traditional reinforcement materials primarily consist of micron or submicron-sized particles. However, recent studies have demonstrated that nanoparticles of equal mass or volume fraction exhibit a more pronounced strengthening effect within the matrix than conventional micron or submicron-sized particles.

[0004] Titanium carbide ceramics are characterized by high temperature resistance, high strength, and high hardness. Their products are widely used in industries such as metallurgy, electronics, automotive manufacturing, and aerospace. Nano-titanium carbide ceramic particles inherit these advantages, and a small number of patents exist for nano-titanium carbide ceramic particle-reinforced metal-matrix composites. However, there are no public reports on the preparation of nano-titanium carbide ceramic particle-reinforced lightweight metal wires, particularly those suitable for 3D printing. Summary of the Invention

[0005] The present invention provides a nanoparticle-reinforced 7075 aluminum alloy wire suitable for 3D printing and a preparation method thereof. High-strength nano-titanium carbide ceramic particles are introduced into the 7075 aluminum alloy wire via a molten salt-ultrasonic dispersion-cleaning-filtration-powder sintering-hot extrusion-drawing process. The resulting product can be used to fabricate complex-shaped 7075 aluminum alloy components while also improving the material's mechanical properties. Wire materials with varying nano-titanium carbide contents can also be prepared as needed. The method features simple and controllable operating steps, is amenable to scalable production, and offers high batch-to-batch repeatability.

[0006] The present invention aims to provide a method for preparing nanoparticle-reinforced 7075 aluminum alloy wire suitable for 3D printing, comprising the following steps:

[0007] (1) 7075 aluminum alloy powder, nano-titanium carbide and inorganic salt are uniformly mixed and ball-milled, and sieved to obtain precursor powder A; the volume ratio of the 7075 aluminum alloy powder to the nano-titanium carbide is 1:0.01-0.1, and the volume ratio of the sum of the volumes of the 7075 aluminum alloy powder and the nano-titanium carbide to the inorganic salt is v(7075 aluminum alloy powder+nano-titanium carbide):v(inorganic salt)=5-15:85-95; the average particle size of the nano-titanium carbide is 40-60 nm;

[0008] (2) The precursor powder A of step (1) is vacuum heated, and after the powder is melted, the melt is subjected to ultrasonic dispersion treatment, and then cooled, and the resulting block solid is crushed to a powder particle size of less than 5 mm to obtain precursor powder B; the vacuum degree during the vacuum heating is ≤6×10 -2 Pa;

[0009] (3) Dissolve the precursor powder B obtained in step (2) in deionized water and stir, then precipitate the dissolved suspension, pour out the upper suspension, and leave the black granular material at the bottom. Repeat this step 3 to 5 times to obtain the bottom mixed solution C.

[0010] (4) filtering and drying the bottom mixed solution C obtained in step (3), and then crushing and sieving the obtained black powder to obtain the nanoparticle-reinforced 7075 aluminum alloy composite powder, wherein the volume fraction of the nanoparticle content in the composite powder is between 0.68% and 4.50%;

[0011] (5) mixing the composite powder obtained in step (4) with 7075 aluminum alloy powder and then sintering the mixture by powder metallurgy to obtain a bulk material of 7075 aluminum alloy reinforced with nanoparticles, wherein the volume content of the nanoparticles in the sintered bulk material is between 0.5% and 1.0%;

[0012] (6) heating the bulk material of the nanoparticle-reinforced 7075 aluminum alloy obtained in step (5) and placing it into an extruder to obtain a wire material having the nanoparticle-reinforced 7075 aluminum alloy after extrusion;

[0013] (7) The wire material with nanoparticle-reinforced 7075 aluminum alloy obtained in step (6) is subjected to multiple drawing passes to obtain a nanoparticle-reinforced 7075 aluminum alloy wire material with a desired diameter, wherein the volume percentage of the nanoparticle-reinforced phase in the wire material is between 0.5% and 1.0%.

[0014] The present invention introduces nano-titanium carbide ceramic particles into a 7075 aluminum alloy matrix, and then obtains a 7075 aluminum alloy wire material reinforced with nano-titanium carbide particles through hot extrusion-drawing. The strengthening effect of the nanoparticles is utilized to improve the mechanical properties and wear resistance of the composite material, which has positive significance for expanding the application of 7075 aluminum alloy composite materials in the industrial field.

[0015] After many experiments, the inventors of the present invention found that if the addition content and particle size of nano-titanium carbide are not properly selected, not only can the preparation of the final wire material not be guaranteed, but the performance may also be weakened: when the particle size of the titanium carbide particles is too large and the particles are too coarse, it is not easy to be introduced into the interior of the 7075 alloy during the mixed melting process, and thus it cannot play a good particle reinforcement role; and if the particle size of the nano-particles is too small, it is difficult to improve the agglomeration defects of the nano-particles, resulting in difficulty in effectively dispersing the nano-particles in the wire after drawing, which is not conducive to improving the material performance. When the relative content of nano-titanium carbide in the precursor powder A is too high, it will cause some nano-particles to agglomerate, resulting in uneven dispersion and reduced nano-particle utilization, thereby reducing the particle dispersion effect and increasing costs. In addition, when the volume content of nano-titanium carbide particles in the designed wire is greater than 1%, in the actual drawing state, in addition to causing the deformation performance of the material to deteriorate rapidly, it will also increase the probability of wire breakage during the drawing process.

[0016] The preparation method of the nanoparticle reinforced 7075 aluminum alloy wire material described in the present invention adopts a molten salt-ultrasonic dispersion-cleaning-filtration-powder sintering-hot extrusion-drawing combined method to prepare the product. The product is prepared by utilizing the characteristics that the molten liquid metal 7075 aluminum alloy, titanium carbide ceramic particles and molten salt are insoluble in each other. The molten salt is used as a dispersion carrier to effectively introduce specific nano-sized solid ceramic particles into the liquid 7075 alloy liquid material, and the reinforcing material particles are uniformly dispersed in the liquid metal through ultrasonic dispersion. Since titanium carbide has the advantages of high strength, high hardness, high temperature resistance and small thermal expansion coefficient, the metal powder material prepared by the method has the characteristics of high hardness, high strength and high wear resistance, which provides raw material guarantees and new ideas for expanding the application of high-strength 7075 aluminum alloy composite materials in the industrial field. At the same time, the nano-titanium carbide particle reinforced 7075 aluminum alloy-based powder material can also expand the application of 7075 aluminum alloy-based composite materials in additive manufacturing, hot isostatic pressing and powder metallurgy. The material preparation method of the present invention has simple operating steps, high repeatability, safety and environmental protection, and can realize industrial small-scale production.

[0017] Preferably, the average particle size of the 7075 aluminum alloy powder in step (1) is 10 to 53 μm, and the average particle size of the inorganic salt is 500 to 650 μm. After multiple comparative experiments, the inventors found that if the amount of nano-titanium carbide added is too large, it may cause the nano-particles to agglomerate on the surface of the liquid metal, resulting in a decrease in ultrasonic dispersion efficiency and failure to achieve the effect of dispersion strengthening. The limitation of the titanium carbide size cannot improve the above defects; if the amount added is too small, the expected performance enhancement effect cannot be achieved. At the above ratio, the dispersion uniformity of the nano-titanium carbide ceramic particles in the melt after ultrasonic dispersion is better, and the mechanical properties of the resulting product are further improved.

[0018] In addition, inorganic salts serve as carriers for 7075 aluminum alloy and reinforcing particles in molten salt dispersion. If the proportion is inappropriate, it will inevitably cause problems with material uniformity and production efficiency.

[0019] Preferably, in step (1), the ball milling medium used for ball milling the 7075 aluminum alloy powder, nano-titanium carbide and inorganic salt is titanium carbide grinding balls, with m (titanium carbide grinding balls): m (7075 aluminum alloy powder + nano-titanium carbide + inorganic salt) = 3 to 5:1; the ball milling time is 12 to 24 hours, and the rotation speed is 250 to 300 r / min.

[0020] The ball milling process is performed using grinding balls made of the same material as the reinforcing material, and the size of the ball milling raw materials and the ball milling parameters are limited, which can effectively improve the ball milling efficiency and is not prone to introducing impurities.

[0021] Preferably, the inorganic salt comprises at least one of potassium chloride and calcium chloride. The two inorganic salts have similar properties and can be mixed in any proportion and effectively used as molten salts and dispersion carriers.

[0022] Preferably, the vacuum heating temperature in step (2) is 800° C. to 830° C. for 5 to 10 minutes, and the ultrasonic dispersion treatment is performed for 2 to 3 minutes at a power of 800 to 1000 W. The object of the ultrasonic dispersion treatment is a molten salt particle mixture, so a specific time and power are required to ensure that the ceramic titanium carbide particles in the melt can be effectively and evenly dispersed into the powder material.

[0023] More preferably, during the ultrasonic dispersion treatment in step (2), the ceramic ultrasonic probe is inserted into the melt for ultrasonic dispersion, and when the ceramic ultrasonic probe is inserted into the melt, the probe tip is located two-thirds below the melt surface.

[0024] Preferably, the precipitation time of the suspension in step (3) is 1 to 2 minutes, and the mass ratio of the deionized water to the precursor powder B is greater than 5:1; and the drying temperature in step (4) is 100°C to 150°C.

[0025] Preferably, in step (5), the composite powder is mixed with 7050 aluminum powder according to the nanoparticle content required by the metal wire, and then sintered, and the powder metallurgy sintering temperature is 560° C. to 580° C.

[0026] Preferably, the heating temperature of the bulk material of the nanoparticle-reinforced 7075 aluminum alloy powder in step (6) is 470° C. to 500° C., and the extrusion ratio of the bulk material is 80 to 150.

[0027] Preferably, the wire material in step (7) needs to be stress-relief annealed at 420°C to 440°C, and needs to be kept warm and annealed before and after each drawing. The annealing and holding temperatures are 420°C to 440°C and 320°C to 350°C, respectively, and the drawing speed is 5 to 20 m / min.

[0028] Compared with patent CN115889762A (a nano-ceramic particle reinforced 7075 aluminum alloy composite powder and its preparation method and application), there are obvious differences in the nanoparticle content in the material due to different application scenarios. In order to solve the problem of stress in welded joints, the material disclosed in patent CN115889762A needs to use a composite material with a higher particle content, and the volume fraction of its particle content is greater than 4%. At this volume fraction, the material cannot be drawn and cannot be prepared into aluminum alloy wire suitable for printing. The wire prepared by the present invention has a volume fraction of particle content not higher than 1%. Under this condition, the material can be drawn into wire after extrusion.

[0029] Furthermore, compared to pure 7050 aluminum, the addition of nano-ceramic particles generates greater internal stress after extrusion and drawing, making direct drawing or multi-pass continuous drawing impossible and requiring annealing. Therefore, this differs from the continuous drawing of 7050 aluminum wire.

[0030] The present invention also protects the nanoparticle-reinforced 7075 aluminum alloy wire suitable for 3D printing prepared by the above preparation method.

[0031] The present invention also protects the use of the nanoparticle-reinforced 7075 aluminum alloy wire in 3D printing. Compared to existing 7075 wire materials, the nanoparticle-reinforced 7075 aluminum alloy wire material prepared by the present invention has higher mechanical strength and hardness in printed components. Compared with existing 7075 wire materials, the nanoparticle-reinforced 7075 aluminum alloy wire material proposed by the present invention has a mechanical strength increase of more than 15% and a hardness increase of more than 10%.

[0032] Compared with the prior art, the present invention has the following advantages: It provides a nanoparticle-reinforced 7075 aluminum alloy wire suitable for 3D printing and a preparation method thereof. The preparation method utilizes molten salt-ultrasonic dispersion-cleaning-filtration-powder sintering-hot extrusion-drawing steps to prepare the product. Utilizing the mutually insoluble nature of the melted 7075 aluminum alloy powder, titanium carbide ceramic particles, and molten salt, the molten salt serves as a dispersion carrier to effectively introduce specific nano-sized solid ceramic particles into the 7075 aluminum alloy material. Ultrasonic dispersion is then used to uniformly disperse the reinforcing material particles in the liquid metal. The resulting nanoparticle-reinforced 7075 aluminum alloy composite powder, obtained after cooling, is metallurgically sintered with 7075 aluminum alloy powder to produce a nanoparticle-reinforced 7075 aluminum alloy bulk composite material. This is then hot-extruded to produce the desired nanoparticle-reinforced 7075 aluminum alloy wire material. This is then drawn to produce a particle-reinforced 7075 aluminum alloy wire material with a specified diameter suitable for 3D printing. Because titanium carbide has the advantages of high strength, high hardness, and high temperature resistance, the 7075 aluminum alloy wire material prepared by the method has the advantages of high strength, high operating temperature, and good wear resistance, providing a new idea for expanding the application of 7075 aluminum alloy-based composite materials in the field of industrial 3D printing. In addition, the reinforcing phase of the nano-titanium carbide reinforced 7075 aluminum alloy wire material, that is, the nano-titanium carbide content, can be adjusted within a certain range to obtain wire materials with different properties, thereby selecting the appropriate wire material according to the component requirements. The material preparation method of the present invention has simple operating steps, high repeatability, safety and environmental protection, and can achieve industrial small-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is an optical image of the nanoparticle-reinforced 7075 aluminum alloy wire material prepared in Example 1 of the present invention;

[0034] Figure 2 This is an optical photograph of the nanoparticle-reinforced 7075 aluminum alloy wire prepared in Comparative Example 2 of the present invention after being broken;

[0035] Figure 3 This is the SEM image of the interior of the nanoparticle-reinforced 7075 aluminum alloy wire material prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0036] The present invention will be described in further detail below with reference to the examples. These examples are intended to illustrate the present invention only and are not intended to limit the scope of the present invention. The experimental methods in the following examples, for which specific conditions are not specified, are generally based on conventional conditions in the art or the conditions recommended by the manufacturer; the raw materials and reagents used, unless otherwise specified, are deemed to be raw materials and reagents that can be obtained through commercial channels such as conventional markets. Any non-substantial changes and substitutions made by those skilled in the art on the basis of the present invention fall within the scope of protection claimed in the present invention.

[0037] Example 1

[0038] An embodiment of a nanoparticle-reinforced 7075 aluminum alloy wire suitable for 3D printing and a method for preparing the same, according to the present invention, comprises the following steps:

[0039] (1) 7075 aluminum alloy powder, nano-titanium carbide and potassium chloride are placed in a mixing bottle in an argon-protected glove box, titanium carbide grinding balls are added, the bottle is sealed and placed on a mixer for ball milling, and sieved to obtain precursor powder A; the volume ratio of 7075 aluminum alloy powder, nano-titanium carbide and calcium chloride is: v (7075 aluminum alloy powder): v (nano-titanium carbide): v (inorganic salt) = 9.5:0.5:90; the average particle size of nano-titanium carbide is 50nm; the average particle size of 7075 aluminum alloy powder is 40μm, and the average particle size of inorganic salt is 500μm; the mass ratio of titanium carbide grinding balls to 7075 aluminum alloy powder, nano-titanium carbide and inorganic salt is 4:1; the ball milling time is 24h, and the rotation speed is 300r / min;

[0040] (2) The precursor powder A of step (1) was vacuum heated for 10 min. After the powder melted, the obtained melt was inserted into a ceramic ultrasonic probe with the probe tip located two-thirds below the melt surface. Ultrasonic dispersion was performed at a power of 500 W for 3 min. The powder was poured into a ceramic boat for cooling. The obtained block solid was crushed to a powder particle size of <5 mm to obtain precursor powder B. The vacuum degree during vacuum heating was ≤6×10 -2 Pa; the heating temperature is 820°C;

[0041] (3) The precursor powder B obtained in step (2) was placed in deionized water and dissolved with stirring, and then the dissolved suspension was precipitated for 2 minutes, and the upper suspension was poured out, leaving the bottom black granular material, and this step was repeated three times to obtain the bottom mixed solution C; the mass ratio of the deionized water to the precursor powder B was 8:1;

[0042] (4) The bottom mixed solution C obtained in step (3) is filtered and dried at 120° C., and the resulting black powder is crushed and sieved in sequence to obtain the nanoparticle-reinforced 7075 aluminum alloy powder composite material, wherein the volume fraction of the nanoparticles in the composite powder is 2.5%;

[0043] (5) The composite powder obtained in step (4) is converted with 7075 aluminum alloy powder according to the volume fraction of ceramic particles in the 7075 aluminum alloy wire being 1%, and the composite powder and 7075 aluminum alloy powder are mixed. After the mixing is uniform, the mixed powder is subjected to powder metallurgy sintering at 580° C. / 30 MPa using SPS to obtain the bulk material of the nanoparticle-reinforced 7075 aluminum alloy;

[0044] (6) The bulk material of the nanoparticle-reinforced 7075 aluminum alloy obtained in step (5) is heated and kept at 490° C. After keeping the heat for 20 minutes, the bulk material is placed in an extruder and extruded at an extrusion ratio of 1:90. After extrusion, a wire material having a diameter of 6 mm and nanoparticle-reinforced 7075 aluminum alloy is obtained;

[0045] (7) The wire material of the nanoparticle-reinforced 7075 aluminum alloy obtained in step (6) is first annealed at 420° C. for 2 h. After the wire material is cooled to 330° C., it is drawn at a speed of 15 m / min. After the drawing is completed, the above steps are repeated until a wire material of the desired diameter is obtained. At this time, the volume fraction of the ceramic particles in the 7075 aluminum alloy wire material is 1%.

[0046] The obtained product was placed under an optical camera for observation, and the results were as follows: Figure 1 As shown. SEM spectrum is as Figure 3 shown.

[0047] Example 2

[0048] The only difference between this embodiment and embodiment 1 is that the steps are:

[0049] (1) 7075 aluminum alloy powder, nano-titanium carbide and calcium chloride are placed in a mixing bottle in an argon-protected glove box, titanium carbide grinding balls are added, the mixture is sealed and placed on a mixer for ball milling, and sieved to obtain precursor powder A; the volume ratio of the 7075 aluminum alloy powder, nano-titanium carbide and calcium chloride is: v (7075 aluminum alloy powder): v (nano-titanium carbide): v (inorganic salt) = 9.1:0.9:90; the average particle size of nano-titanium carbide is 40 nm; the average particle size of the 7075 aluminum alloy powder is 40 μm, and the average particle size of the inorganic salt is 500 μm; the mass ratio of titanium carbide grinding balls to the three raw materials of 7075 aluminum alloy powder, nano-titanium carbide and inorganic salt is 4:1; the ball milling time is 24 h, and the rotation speed is 300 r / min;

[0050] (2) The precursor powder A described in step (1) was vacuum heated for 10 min. After the powder melted, the obtained melt was inserted into a ceramic ultrasonic probe with the probe tip located two-thirds below the melt surface. Ultrasonic dispersion was performed at 800 W power for 3 min. The powder was poured into a ceramic boat for cooling. The obtained block solid was crushed to a powder particle size of <5 mm to obtain precursor powder B. The vacuum degree during vacuum heating was ≤6×10 -2 Pa; heating temperature is 810℃;

[0051] (3) The precursor powder B obtained in step (2) was placed in deionized water and dissolved with stirring, and then the dissolved suspension was precipitated for 2 minutes, and the upper suspension was poured out, leaving the bottom black granular material, and this step was repeated three times to obtain the bottom mixed solution C; the mass ratio of deionized water to precursor powder B was 8:1;

[0052] (4) The bottom mixed solution C obtained in step (3) is filtered and dried at 120° C., and the resulting black powder is crushed and sieved in sequence to obtain the nanoparticle-reinforced 7075 aluminum alloy powder composite material, wherein the volume fraction of the nanoparticles in the composite powder is 4.5%;

[0053] (5) The composite powder obtained in step (4) is converted to 7075 aluminum alloy powder according to the volume fraction of ceramic particles in the 7075 aluminum alloy wire being 0.75%, and the composite powder and 7075 powder are mixed. After mixing evenly, the mixed powder is subjected to powder metallurgy sintering at 570°C / 20MPa using SPS to obtain the bulk material of the nanoparticle-reinforced 7075 aluminum alloy;

[0054] (6) heating the bulk material of the nanoparticle-reinforced 7075 aluminum alloy obtained in step (5) at 480° C. for 20 minutes, placing the bulk material into an extruder, and extruding it at an extrusion ratio of 1:150 to obtain a wire material having nanoparticle-reinforced 7075 aluminum alloy;

[0055] (7) The wire material of the nanoparticle-reinforced 7075 aluminum alloy obtained in step (6) is first annealed at 420° C. for 2 h. After the wire is cooled to 350° C., it is drawn at a speed of 10 m / min. After the drawing is completed, the above steps are repeated until a wire material of the desired diameter is obtained. At this time, the volume fraction of the ceramic particles in the 7075 aluminum alloy wire is 0.75%.

[0056] Example 3

[0057] The only difference between this embodiment and embodiment 1 is that the steps are:

[0058] (1) 7075 aluminum alloy powder, nano-titanium carbide and potassium chloride are placed in a mixing bottle in an argon-protected glove box, titanium carbide grinding balls are added, the mixture is sealed and placed on a mixer for ball milling, and sieved to obtain precursor powder A; the volume ratio of 7075 aluminum alloy powder, nano-titanium carbide and potassium chloride is: v (7075 aluminum alloy powder): v (nano-titanium carbide): v (inorganic salt) = 9.2:0.8:90; the average particle size of nano-titanium carbide is 60 nm; the average particle size of 7075 aluminum alloy powder is 40 μm, and the average particle size of inorganic salt is 650 μm; the mass ratio of titanium carbide grinding balls to 7075 aluminum alloy powder, nano-titanium carbide and inorganic salt is 4:1; the ball milling time is 24 h, and the rotation speed is 300 r / min;

[0059] (2) The precursor powder A of step (1) was vacuum heated for 10 min. After the powder melted, the obtained melt was inserted into a ceramic ultrasonic probe with the probe tip located two-thirds below the melt surface. Ultrasonic dispersion was performed at 800 W power for 3 min. The powder was poured into a ceramic boat for cooling. The obtained block solid was crushed to a powder particle size of <5 mm to obtain precursor powder B. The vacuum degree during vacuum heating was ≤6×10 -2 Pa; heating temperature is 820℃;

[0060] (3) The precursor powder B obtained in step (2) was placed in deionized water and dissolved with stirring, and then the dissolved suspension was precipitated for 2 minutes, and the upper suspension was poured out, leaving the bottom black granular material, and this step was repeated three times to obtain the bottom mixed solution C; the mass ratio of deionized water to precursor powder B was 8:1;

[0061] (4) The bottom mixed solution C obtained in step (3) was filtered and dried at 120° C., and the obtained black powder was crushed and sieved in sequence to obtain the nanoparticle-reinforced 7075 aluminum alloy powder composite material. At this time, the volume fraction of the nanoparticle content in the composite powder was 4.2%;

[0062] (5) The composite powder obtained in step (4) is converted to 7075 aluminum alloy powder according to the volume fraction of ceramic particles in the 7075 aluminum alloy wire being 0.5%, and the composite powder and 7075 powder are mixed. After mixing evenly, the mixed powder is subjected to powder metallurgy sintering at 580° C. / 20 MPa using SPS to obtain the bulk material of the nanoparticle-reinforced 7075 aluminum alloy;

[0063] (6) The bulk material of the nanoparticle-reinforced 7075 aluminum alloy obtained in step (5) is heated and kept warm at 490° C. After keeping warm for 20 minutes, the bulk material is placed in an extruder and extruded at an extrusion ratio of 1:120 to obtain a wire material having nanoparticle-reinforced 7075 aluminum alloy;

[0064] (7) The wire material of the nanoparticle-reinforced 7075 aluminum alloy obtained in step (6) is first annealed at 440°C for 2 hours. After the wire is cooled to 320°C, it is drawn at a speed of 20 m / min. After the drawing is completed, the above steps are repeated until a wire material of the desired diameter is obtained. At this time, the volume fraction of the ceramic particles in the 7075 aluminum alloy wire is 0.5%.

[0065] Example 4

[0066] The only difference between this embodiment and embodiment 1 is that the steps are:

[0067] (1) 7075 aluminum alloy powder, nano-titanium carbide, potassium chloride and calcium chloride are placed in a mixing bottle in an argon-protected glove box, titanium carbide grinding balls are added, the bottle is sealed and placed on a mixer for ball milling, and sieved to obtain precursor powder A; the volume ratio of 7075 aluminum alloy powder, nano-titanium carbide, potassium chloride and calcium chloride is: v(7075 aluminum alloy powder):v(nano-titanium carbide):v(potassium chloride):v(calcium chloride)=9.4:0.6:20:70; the average particle size of nano-titanium carbide is 50nm; the average particle size of 7075 aluminum alloy powder is 26μm, the average particle size of potassium chloride is 500μm; the average particle size of calcium chloride is 650μm; the mass ratio of titanium carbide grinding balls to 7075 aluminum alloy powder, nano-titanium carbide and inorganic salt is 4:1; the ball milling time is 24h, and the rotation speed is 300r / min;

[0068] (2) The precursor powder A of step (1) is vacuum heated for 10 minutes. After the powder is melted, the obtained melt is inserted into a ceramic ultrasonic probe with the probe tip located two-thirds below the melt surface. Ultrasonic dispersion treatment is performed at 800W power for 3 minutes. The powder is poured into a ceramic boat for cooling. The obtained block solid is crushed to a powder particle size of less than 5 mm to obtain precursor powder B. The vacuum degree during the vacuum heating is ≤6×10-2 Pa; the heating temperature is 830°C;

[0069] (3) The precursor powder B obtained in step (2) was placed in deionized water and dissolved with stirring, and then the dissolved suspension was precipitated for 2 minutes, and the upper suspension was poured out, leaving the bottom black granular material, and this step was repeated three times to obtain the bottom mixed solution C; the mass ratio of the deionized water to the precursor powder B was 8:1;

[0070] (4) The bottom mixed solution C obtained in step (3) was filtered and dried at 120° C., and the obtained black powder was crushed and sieved in sequence to obtain the nanoparticle-reinforced 7075 aluminum alloy powder composite material, wherein the volume fraction of the nanoparticles in the composite powder was 3.0%;

[0071] (5) The composite powder obtained in step (4) is converted to 7075 aluminum alloy powder according to the volume fraction of ceramic particles in the 7075 aluminum alloy wire being 1%, and the composite powder and 7075 powder are mixed. After mixing evenly, the mixed powder is subjected to powder metallurgy sintering at 560° C. / 30 MPa using SPS to obtain the bulk material of the nanoparticle-reinforced 7075 aluminum alloy;

[0072] (6) The bulk material of the nanoparticle-reinforced 7075 aluminum alloy obtained in step (5) is heated and kept warm at 500° C. After keeping warm for 20 minutes, the bulk material is placed in an extruder and extruded at an extrusion ratio of 1:80 to obtain a wire material having nanoparticle-reinforced 7075 aluminum alloy;

[0073] (7) The wire material of the nanoparticle-reinforced 7075 aluminum alloy obtained in step (6) is first annealed at 420° C. for 2 h. After the wire material is cooled to 350° C., it is drawn at a speed of 5 m / min. After the drawing is completed, the above steps are repeated until a wire material of the desired diameter is obtained. At this time, the volume fraction of the ceramic particles in the 7075 aluminum alloy wire material is 1%.

[0074] Example 5

[0075] The only difference between this embodiment and embodiment 1 is that the steps are:

[0076] (1) 7075 aluminum alloy powder, nano-titanium carbide, potassium chloride and calcium chloride are placed in a mixing bottle in an argon-protected glove box, titanium carbide grinding balls are added, the mixture is sealed and placed on a mixer for ball milling, and sieved to obtain precursor powder A; the volume ratio of 7075 aluminum alloy powder, nano-titanium carbide, potassium chloride and calcium chloride is: v(7075 aluminum alloy powder): v(nano-titanium carbide): v(potassium chloride): v(calcium chloride) = 9.9:0.1:40:50; the average particle size of nano-titanium carbide is 50 nm; the average particle size of 7075 aluminum alloy powder is 26 μm, the average particle size of potassium chloride is 500 μm; the average particle size of calcium chloride is 500 μm; the mass ratio of titanium carbide grinding balls to the three raw materials of 7075 aluminum alloy powder, nano-titanium carbide and inorganic salt is 4:1; the ball milling time is 24 h, and the rotation speed is 300 r / min;

[0077] (2) The precursor powder A of step (1) was vacuum heated for 10 min. After the powder melted, the obtained melt was inserted into a ceramic ultrasonic probe with the probe tip located two-thirds below the melt surface. Ultrasonic dispersion was performed at a power of 600 W for 3 min. The powder was poured into a ceramic boat for cooling. The obtained block solid was crushed to a powder particle size of <5 mm to obtain precursor powder B. The vacuum degree during vacuum heating was ≤6×10 -2 Pa; heating temperature is 810℃;

[0078] (3) The precursor powder B obtained in step (2) was placed in deionized water and dissolved with stirring, and then the dissolved suspension was precipitated for 2 minutes, and the upper suspension was poured out, leaving the bottom black granular material, and this step was repeated three times to obtain the bottom mixed solution C; the mass ratio of deionized water to precursor powder B was 8:1;

[0079] (4) The bottom mixed solution C obtained in step (3) was filtered and dried at 120° C., and the obtained black powder was crushed and sieved in sequence to obtain the nanoparticle-reinforced 7075 aluminum alloy powder composite material, wherein the volume fraction of the nanoparticles in the composite powder was 0.68%;

[0080] (5) The composite powder obtained in step (4) and the 7075 aluminum alloy powder are converted according to the volume fraction of the ceramic particles in the 7075 aluminum alloy wire being 0.5%, and the composite powder and the 7075 powder are mixed. After mixing evenly, the mixed powder is subjected to powder metallurgy sintering at 570°C / 30MPa using SPS to obtain a bulk material of the nanoparticle-reinforced 7075 aluminum alloy;

[0081] (6) heating the bulk material of the nanoparticle-reinforced 7075 aluminum alloy obtained in step (5) at 480° C. for 20 minutes, placing the bulk material into an extruder, and extruding it at an extrusion ratio of 1:100 to obtain a wire material having nanoparticle-reinforced 7075 aluminum alloy;

[0082] (7) The wire material of the nanoparticle-reinforced 7075 aluminum alloy obtained in step (6) is first annealed at 440°C for 2 hours. After the wire is cooled to 350°C, it is drawn at a speed of 10 m / min. After the drawing is completed, the above steps are repeated until a wire material of the desired diameter is obtained. At this time, the volume fraction of the ceramic particles in the 7075 aluminum alloy wire is 0.5%.

[0083] Example 6

[0084] The only difference between this embodiment and embodiment 1 is that the steps are:

[0085] (1) 7075 aluminum alloy powder, nano-titanium carbide and potassium chloride are placed in a mixing bottle in an argon-protected glove box, titanium carbide grinding balls are added, the mixture is sealed and placed on a mixer for ball milling, and sieved to obtain precursor powder A; the volume ratio of 7075 aluminum alloy powder, nano-titanium carbide and potassium chloride is: v (7075 aluminum alloy powder): v (nano-titanium carbide): v (inorganic salt) = 14.4:0.6:85; the average particle size of nano-titanium carbide is 60 nm; the average particle size of 7075 aluminum alloy powder is 53 μm, and the average particle size of inorganic salt is 650 μm; the mass ratio of titanium carbide grinding balls to 7075 aluminum alloy powder, nano-titanium carbide and inorganic salt is 4:1; the ball milling time is 24 h, and the rotation speed is 300 r / min;

[0086] (2) The precursor powder A of step (1) was vacuum heated for 10 min. After the powder melted, the obtained melt was inserted into a ceramic ultrasonic probe with the probe tip located two-thirds below the melt surface. Ultrasonic dispersion was performed at a power of 700 W for 3 min. The powder was poured into a ceramic boat for cooling. The obtained block solid was crushed to a powder particle size of <5 mm to obtain precursor powder B. The vacuum degree during vacuum heating was ≤6×10 -2 Pa; heating temperature is 810℃;

[0087] (3) The precursor powder B obtained in step (2) was placed in deionized water and dissolved with stirring, and then the dissolved suspension was precipitated for 2 minutes, and the upper suspension was poured out, leaving the bottom black granular material, and this step was repeated three times to obtain the bottom mixed solution C; the mass ratio of deionized water to precursor powder B was 6:1;

[0088] (4) The bottom mixed solution C obtained in step (3) was filtered and dried at 120° C., and the obtained black powder was crushed and sieved in sequence to obtain the nanoparticle-reinforced 7075 aluminum alloy powder composite material, wherein the volume fraction of the nanoparticles in the composite powder was 2.1%;

[0089] (5) The composite powder obtained in step (4) is converted to 7075 aluminum alloy powder according to the volume fraction of ceramic particles in the 7075 aluminum alloy wire being 0.8%, and the composite powder and 7075 powder are mixed. After mixing evenly, the mixed powder is subjected to powder metallurgy sintering at 560°C / 30MPa using SPS to obtain a bulk material of nanoparticle-reinforced 7075 aluminum alloy;

[0090] (6) heating the bulk material of the nanoparticle-reinforced 7075 aluminum alloy obtained in step (5) at 490° C. for 15 minutes, placing the bulk material into an extruder, and extruding it at an extrusion ratio of 1:90 to obtain a wire material having nanoparticle-reinforced 7075 aluminum alloy;

[0091] (7) The wire material of the nanoparticle-reinforced 7075 aluminum alloy obtained in step (6) is first annealed at 420° C. for 2 h. After the wire material is cooled to 330° C., it is drawn at a speed of 20 m / min. After the drawing is completed, the above steps are repeated until a wire material of the desired diameter is obtained. At this time, the volume fraction of the ceramic particles in the 7075 aluminum alloy wire material is 0.8%.

[0092] Example 7

[0093] The only difference between this embodiment and embodiment 1 is that the steps are:

[0094] (1) 7075 aluminum alloy powder, nano-titanium carbide, calcium chloride and potassium chloride are placed in a mixing bottle in an argon-protected glove box, titanium carbide grinding balls are added, the mixture is sealed and placed on a mixer for ball milling, and sieved to obtain precursor powder A; the volume ratio of 7075 aluminum alloy powder, nano-titanium carbide, potassium chloride and calcium chloride is: v(7075 aluminum alloy powder): v(nano-titanium carbide): v(potassium chloride): v(calcium chloride) = 9.2:0.8:80:10; the average particle size of nano-titanium carbide is 50 nm; the average particle size of 7075 aluminum alloy powder is 26 μm, the average particle size of potassium chloride is 500 μm; the average particle size of calcium chloride is 600 μm; the mass ratio of titanium carbide grinding balls to the three raw materials of 7075 aluminum alloy powder, nano-titanium carbide and inorganic salt is 4:1; the ball milling time is 24 h, and the rotation speed is 300 r / min;

[0095] (2) The precursor powder A of step (1) was vacuum heated for 10 min. After the powder melted, the melt was inserted into a ceramic ultrasonic probe and ultrasonically dispersed at 800 W for 3 min. The melt was poured into a ceramic boat for cooling. The resulting block solid was crushed to a powder particle size of <5 mm to obtain precursor powder B. The vacuum degree during vacuum heating was ≤6×10 -2 Pa; heating temperature is 820℃;

[0096] (3) The precursor powder B obtained in step (2) was placed in deionized water and dissolved with stirring, and then the dissolved suspension was precipitated for 3 minutes, and the upper suspension was poured out, leaving the bottom black granular material, and this step was repeated 5 times to obtain the bottom mixed solution C; the mass ratio of deionized water to precursor powder B was 6:1;

[0097] (4) The bottom mixed solution C obtained in step (3) was filtered and dried at 150° C., and the resulting black powder was pulverized and sieved in sequence to obtain a nanoparticle-reinforced 7075 aluminum alloy powder composite material. At this time, the volume fraction of the nanoparticle content in the composite powder was 4.2%;

[0098] (5) The composite powder obtained in step (4) is converted to 7075 aluminum alloy powder according to the volume fraction of ceramic particles in the 7075 aluminum alloy wire being 1%, and the composite powder and 7075 powder are mixed. After mixing evenly, the mixed powder is subjected to powder metallurgy sintering at 565° C. / 30 MPa using SPS to obtain the bulk material of the nanoparticle-reinforced 7075 aluminum alloy;

[0099] (6) The bulk material of the nanoparticle-reinforced 7075 aluminum alloy obtained in step (5) is heated and kept warm at 470° C. After keeping warm for 20 minutes, the bulk material is placed in an extruder and extruded at an extrusion ratio of 1:100 to obtain a wire material having nanoparticle-reinforced 7075 aluminum alloy;

[0100] (7) The wire material of the nanoparticle-reinforced 7075 aluminum alloy obtained in step (6) is first annealed at 430° C. for 2 h. After the wire is cooled to 320° C., it is drawn at a speed of 15 m / min. After the drawing is completed, the above steps are repeated until a wire material of the desired diameter is obtained. At this time, the volume fraction of the ceramic particles in the 7075 aluminum alloy wire is 1%.

[0101] Comparative Example 1

[0102] The only difference between this comparative example and Example 1 is that step (1) is:

[0103] 7075 aluminum alloy powder, nano-titanium carbide and potassium chloride were placed in a mixing bottle in an argon-protected glove box, titanium carbide grinding balls were added, the mixture was sealed and placed on a mixer for ball milling, and sieved to obtain precursor powder A; the volume ratio of 7075 aluminum alloy powder, nano-titanium carbide and potassium chloride was: v(7075 aluminum alloy powder):v(nano-titanium carbide):v(inorganic salt)=10:10:80; the average particle size of nano-titanium carbide was 50 nm; the average particle size of 7075 aluminum alloy powder was 26 μm, and the average particle size of inorganic salt was 500 μm; the mass ratio of titanium carbide grinding balls to 7075 aluminum alloy powder, nano-titanium carbide and inorganic salt was 4:1; the ball milling time was 24 h, and the rotation speed was 300 r / min;

[0104] (6) The bulk material of the nanoparticle-reinforced 7075 aluminum alloy obtained in step (5) is heated and kept warm at 480° C. After keeping warm for 20 minutes, the bulk material is placed in an extruder and extruded at an extrusion ratio of 1:200. After extrusion, a wire material having nanoparticle-reinforced 7075 aluminum alloy is obtained.

[0105] Comparative Example 2

[0106] The difference between this comparative example and Example 1 is that the steps are as follows:

[0107] (1) 7075 aluminum alloy powder, nano-titanium carbide and potassium chloride are placed in a mixing bottle in an argon-protected glove box, titanium carbide grinding balls are added, the bottle is sealed and placed on a mixer for ball milling, and sieved to obtain precursor powder A; the volume ratio of 7075 aluminum alloy powder, nano-titanium carbide and calcium chloride is: v (7075 aluminum alloy powder): v (nano-titanium carbide): v (inorganic salt) = 8:2:90; the average particle size of nano-titanium carbide is 50 nm; the average particle size of 7075 aluminum alloy powder is 26 μm, and the average particle size of inorganic salt is 500 μm; the mass ratio of titanium carbide grinding balls to 7075 aluminum alloy powder, nano-titanium carbide and inorganic salt is 4:1; the ball milling time is 24 h, and the rotation speed is 300 r / min;

[0108] (2) The precursor powder A of step (1) is vacuum heated for 10 min. After the powder is melted, the melt is stirred for 3 min, poured into a ceramic boat and cooled, and the resulting block solid is crushed to a powder particle size of less than 5 mm to obtain precursor powder B; the vacuum degree during the vacuum heating is ≤6×10 -2 Pa; the heating temperature is 1695°C;

[0109] (3) The precursor powder B obtained in step (2) was placed in deionized water and dissolved with stirring, and then the dissolved suspension was precipitated for 2 minutes, and the upper suspension was poured out, leaving the bottom black granular material, and this step was repeated three times to obtain the bottom mixed solution C; the mass ratio of the deionized water to the precursor powder B was 6:1;

[0110] (4) The bottom mixed solution C obtained in step (3) is filtered and dried at 120° C., and the obtained black powder is crushed and sieved in sequence to obtain the 7075 aluminum alloy powder composite material.

[0111] (5) The composite powder obtained in step (4) is mixed with 7075 aluminum alloy powder according to a volume fraction of ceramic particles of 1%. After mixing evenly, the mixed powder is subjected to powder metallurgy sintering at 575°C / 20MPa using SPS to obtain the bulk material of the nanoparticle-reinforced 7075 aluminum alloy.

[0112] (6) heating the bulk material of the nanoparticle-reinforced 7075 aluminum alloy obtained in step (5) at 500° C. for 15 minutes, placing the bulk material into an extruder, and extruding it at an extrusion ratio of 1:120 to obtain a welding rod material having nanoparticle-reinforced 7075 aluminum alloy;

[0113] (7) The wire material of the nanoparticle-reinforced 7075 aluminum alloy obtained in step (6) is first annealed at 400°C for 2 hours. After the wire material is cooled to 320°C, it is drawn at a speed of 25 m / min. After the drawing is completed, the above steps are repeated until the wire material of the desired diameter is obtained.

[0114] Effect Example 1

[0115] In order to verify the effect of the nanoparticle content on the particle dispersion performance of the nanoparticle-reinforced 7050 aluminum alloy wire of the present invention during the mixing process, the wires prepared in Example 1 and Comparative Example 1 were microstructurally observed. It was found that when the nanoparticle content was too high during the mixing process, it was difficult to effectively disperse the nanoparticles in the composite powder after ultrasound, and effective dispersion of the particles could not be achieved even after multiple drawing.

[0116] Effect Example 2

[0117] In order to verify the effect of the annealing process of the nanoparticle reinforced 7075 aluminum alloy wire material during the drawing process of the present invention, the wire materials prepared in Example 1 and Comparative Example 2 were subjected to tensile comparative observation. The results are as follows: Figure 2When the annealing temperature is too low and the drawing speed is too fast, the internal stress of the drawn material is still too large after annealing, which makes the wire easy to break during the drawing process, especially in small diameter (less than 2mm) materials.

[0118] For those skilled in the art, various other corresponding compositions can be made according to the technical solutions and concepts described above, that is, the generated phase is mainly composed of 7075 aluminum-based composite materials reinforced with nano-titanium carbide particles (TiC np / 7075Al), during this process, the particle size of the raw materials, the proportion of the raw materials, the dispersion process, the ultrasonic power, the changes in the drying process, the changes in the sintering process, the extrusion process, and the drawing process, all of these changes and deformations should fall within the scope of protection of the claims of the present invention.

[0119] The above are merely preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be construed as limiting the present invention, and the scope of protection of the present invention should be determined by the scope defined in the claims. Persons skilled in the art will appreciate that improvements and modifications may be made without departing from the spirit and scope of the present invention, and such improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing nanoparticle-reinforced 7075 aluminum alloy wire suitable for 3D printing, characterized in that: The following steps are involved: (1) 7075 aluminum alloy powder, nano-titanium carbide and inorganic salt are uniformly mixed and ball-milled, and sieved to obtain precursor powder A; the volume ratio of the 7075 aluminum alloy powder to the nano-titanium carbide is 1:0.01-0.1, and the volume ratio of the sum of the volumes of the 7075 aluminum alloy powder and the nano-titanium carbide to the inorganic salt is 5-15:85-95; the average particle size of the nano-titanium carbide is 40-60 nm; (2) The precursor powder A of step (1) is vacuum heated, and after the powder is melted, the melt is subjected to ultrasonic dispersion treatment, and then cooled, and the obtained block solid is crushed to a powder particle size of less than 5 mm to obtain precursor powder B; the vacuum degree during the vacuum heating is ≤6×10 -2 Pa; (3) The precursor powder B obtained in step (2) is placed in deionized water and dissolved and stirred, and then the dissolved suspension is precipitated, and the upper suspension is poured out, leaving the bottom black granular material, and this step is repeated 3 to 5 times to obtain the bottom mixed solution C; (4) The bottom mixed solution C obtained in step (3) is filtered and dried, and the obtained black powder is crushed and sieved in sequence to obtain the nanoparticle-reinforced 7075 aluminum alloy composite powder, wherein the volume fraction of the nanoparticle content in the composite powder is between 0.68% and 4.50%; (5) mixing the composite powder obtained in step (4) with 7075 aluminum alloy powder and then performing powder metallurgy sintering to obtain a bulk material of 7075 aluminum alloy reinforced with nanoparticles, wherein the volume content of the nanoparticles in the sintered bulk material is between 0.5% and 1.0%; (6) The bulk material of the nanoparticle-reinforced 7075 aluminum alloy obtained in step (5) is heated and placed into an extruder, and a wire material having nanoparticle-reinforced 7075 aluminum alloy is obtained after extrusion, wherein the heating temperature of the bulk material of the nanoparticle-reinforced 7075 aluminum alloy powder is 470° C. to 500° C., and the extrusion ratio of the bulk material is 80 to 150; (7) The wire material with nanoparticle-reinforced 7075 aluminum alloy obtained in step (6) is subjected to multiple drawing passes to obtain a nanoparticle-reinforced 7075 aluminum alloy wire material with a desired diameter. The volume percentage of the nanoparticle-reinforced phase in the wire material is between 0.5% and 1.0%. The wire material needs to be stress-relieved annealed at 420°C to 440°C, and needs to be kept warm and annealed before and after each drawing. The annealing and holding temperatures are 420°C to 440°C and 320°C to 350°C, respectively. The drawing speed is 5 to 20 m / min.

2. The preparation method according to claim 1, characterized in that The average particle size of the 7075 aluminum alloy powder in step (1) is 10-53 μm, and the average particle size of the inorganic salt is 500-650 μm.

3. The preparation method according to claim 1 or 2, characterized in that In step (1), the ball milling medium used for the ball milling of the 7075 aluminum alloy powder, nano-titanium carbide and inorganic salt is titanium carbide grinding balls, with a ratio of m (titanium carbide grinding balls): m (7075 aluminum alloy powder + nano-titanium carbide + inorganic salt) = 3-5:1; the ball milling time is 12-24 h, and the rotation speed is 250-300 r / min.

4. The preparation method according to claim 1 or 2, characterized in that The vacuum heating in step (2) is performed at a temperature of 800°C to 830°C for 5 to 10 minutes; the ultrasonic dispersion treatment is performed at a power of 800 to 1000 W for 2 to 3 minutes.

5. The preparation method according to claim 1 or 2, characterized in that The precipitation time of the suspension in step (3) is 1 to 2 minutes; the drying temperature in step (4) is 100°C to 150°C.

6. The preparation method according to claim 1 or 2, characterized in that In step (5), the composite powder is mixed with 7050 aluminum powder according to the nanoparticle content required by the metal wire, and then sintered. The powder metallurgy sintering temperature is 560° C. to 580° C.

7. Nanoparticle-reinforced 7075 aluminum alloy wire suitable for 3D printing, prepared by the preparation method according to claim 1 or 2.

8. Use of the nanoparticle-reinforced 7075 aluminum alloy wire according to claim 7 in 3D printing.

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