Aluminum alloy powder for additive manufacturing and preparation method thereof

Abstract

The invention relates to the technical field of metal material additive manufacturing, and particularly discloses aluminum alloy powder for additive manufacturing, which comprises the following components in percentage by mass: 2-6% of silicon carbide powder, 1-2% of copper powder, 0.5-3% of titanium powder and the balance of 6013 aluminum alloy powder. The invention further discloses a preparation method of the aluminum alloy powder for additive manufacturing. The preparation method comprises the following steps that silicon carbide powder, copper powder, titanium powder and 6013 aluminum alloy powder are provided; the first titanium powder and the silicon carbide powder are premixed, and first premixed powder is obtained; second titanium powder and 6013 aluminum alloy powder are mixed, and second premixed powder is obtained; and finally mixing the first premixed powder, the second premixed powder and copper powder to obtain the aluminum alloy powder for additive manufacturing. Through a step-by-step premixing process and composite powder component design, the strength, toughness and wear resistance are synergistically improved, the comprehensive performance is excellent, and the method is suitable for manufacturing precision structural parts in the 3C industry.

Description

Technical Field

[0001] This invention relates to the field of additive manufacturing technology for metallic materials, and more specifically, this invention discloses aluminum alloy powder for additive manufacturing and its preparation method. Background Technology

[0002] Aluminum alloys are widely used in the structural components of consumer electronics (3C) products due to their lightweight, good formability, and certain strength. They are commonly used for components with strict requirements on weight, structure, and appearance, such as mobile phone frames, tablet shells, and laptop casings. 6013 aluminum alloy, a typical Al-Mg-Si-Cu heat-treatable alloy, is one of the commonly used materials. Parts are manufactured using traditional casting, extrusion, or forging processes, followed by machining, heat treatment, and surface treatment to meet structural strength and appearance requirements.

[0003] In existing technologies, to improve the mechanical properties of aluminum alloy parts, especially for 3C products requiring higher drop resistance and surface wear resistance, those skilled in the art typically add reinforcing phases. A typical existing technology involves directly adding a single type of ceramic reinforcing particle, such as silicon carbide or alumina powder, to the aluminum alloy matrix powder. The manufacturing process generally involves mechanically mixing 6013 aluminum alloy powder produced by gas atomization with a predetermined proportion of ceramic powder in a conventional mixing device, followed by selective laser melting (SLM) printing. The printed parts typically undergo solution treatment and artificial aging to obtain the peak strength of the matrix alloy. Another similar existing technology focuses on strengthening by adjusting alloying elements. For example, based on the 6013 aluminum alloy composition, the copper content can be increased, or trace amounts of titanium can be added as a grain refiner. The manufacturing method also involves mixing pre-alloyed powder or corresponding elemental metal powder containing these elements with the matrix powder, followed by SLM printing and subsequent heat treatment to obtain the part.

[0004] However, in practical applications, it still has the following drawbacks: poor bonding between the ceramic reinforcement phase and the metal matrix: During the rapid solidification process of selective laser melting (SLM), ceramic particles (such as silicon carbide powder) and the aluminum alloy matrix have significant differences in physical and chemical properties, which easily leads to weak bonding zones, incomplete fusion, or harmful interfacial reactions at the interface. These microscopic defects can become stress concentration points and crack initiation points, causing the composite material to achieve high hardness while its toughness and impact resistance often decrease simultaneously, making it difficult to meet the requirements of thin-walled structural components with stringent drop resistance performance. Summary of the Invention

[0005] In order to overcome the above-mentioned defects of the prior art, the present invention provides aluminum alloy powder for additive manufacturing and its preparation method, thereby solving the problems mentioned in the background art through the following solutions.

[0006] To achieve the above objectives, the present invention provides the following technical solution: aluminum alloy powder for additive manufacturing, comprising, by total mass of the aluminum alloy powder, the following components: 2%-6% silicon carbide powder, 1%-2% copper powder, 0.5%-3% titanium powder, and the balance being 6013 aluminum alloy powder.

[0007] Preferably, the silicon carbide powder is spherical with a particle size of 5-12 μm.

[0008] Preferably, the copper powder has a particle size of 15-45 μm and a sphericity of ≥85%.

[0009] Preferably, the titanium powder has a particle size of 10-30 μm.

[0010] Preferably, the 6013 aluminum alloy powder is an atomized spherical powder with a particle size of 15-53 μm and a sphericity ≥90%.

[0011] The present invention also provides a method for preparing aluminum alloy powder for additive manufacturing, characterized by comprising the following steps: S1. Provide the aforementioned silicon carbide powder, copper powder, titanium powder and 6013 aluminum alloy powder; S2. The first titanium powder and the silicon carbide powder are premixed to obtain the first premixed powder; S3. Mix the second titanium powder with the 6013 aluminum alloy powder to obtain the second premixed powder; S4. The first premixed powder, the second premixed powder and the copper powder are finally mixed to obtain the aluminum alloy powder for additive manufacturing.

[0012] Preferably, the mass ratio of the first titanium powder to the silicon carbide powder is (0.1-0.3):1.

[0013] Preferably, the final mixing in step S4 is carried out under an inert atmosphere, which is a vacuum or argon atmosphere, and the vacuum degree during the mixing process is ≤1 Pa or the oxygen content is <50 ppm.

[0014] Preferably, in step S4, anhydrous ethanol is added as a dispersant at a mass of 0.1%-0.2% of the silicon carbide powder.

[0015] The technical effects and advantages of this invention are as follows: It solves the problems of weak interfacial bonding and uneven distribution of ceramic reinforcing phases. Through a stepwise premixing process, a portion of titanium powder and silicon carbide powder are premixed to ensure sufficient surface contact. During laser selective melting, a micro-area in-situ reaction between titanium and silicon carbide is preferentially induced, generating a transition layer with good wettability with the aluminum matrix on the surface of the silicon carbide particles. This fundamentally strengthens the interfacial bonding between the ceramic phase and the metal matrix, inhibits the formation of harmful interfacial products, and improves the toughness of the aluminum alloy material. Simultaneously, a suitable ratio of titanium to silicon carbide is selected to avoid the formation of an excessively thick embrittlement layer, which would affect product performance. Attached Figure Description

[0016] Figure 1 This is a process flow diagram of the powder preparation method of the present invention. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] The present invention will be further described in detail below with reference to embodiments, comparative examples and performance test results. These should not be construed as limiting the scope of protection claimed by the present invention.

[0019] It should be noted that the following examples and comparative examples are described in parts by weight to fix the baseline addition amounts of silicon carbide powder, copper powder, second titanium powder, and 6013 aluminum alloy powder, and to explore the effect of the mass ratio of first titanium powder to silicon carbide powder in a single-variable manner. This descriptive method is only for clearly illustrating the experimental design and does not constitute a limitation on the scope of the present invention.

[0020] Example 1 Example 1 provides an aluminum alloy powder for additive manufacturing and a method for preparing the same, and demonstrates the performance of parts printed from this powder. The specific steps are as follows: 1. Powder preparation and pretreatment 1.1 Powder Proportioning Design The aluminum alloy powder comprises the following components in parts by weight: 6013 aluminum alloy powder: 100 parts by weight Silicon carbide powder: 4.3 parts by weight Copper powder: 1.6 parts by weight First titanium powder: 0.8 parts by weight Second titanium powder: 1.2 parts by weight, The mass ratio of the first titanium powder to the silicon carbide powder is approximately 0.186:1.

[0021] Based on the above weight ratio, converted to 100% aluminum alloy powder, the mass percentages of each component are as follows: 6013 aluminum alloy powder approximately 92.7%, silicon carbide powder approximately 4.0%, copper powder approximately 1.5%, second titanium powder approximately 1.1%, and first titanium powder approximately 0.7%.

[0022] 1.2 Powder Parameters and Pretreatment The specific parameters of each component powder are as follows: Silicon carbide powder: Utilizing spherical powder that has undergone high-energy ball milling and spheroidization treatment, its median particle size distribution D... 50 It is 8.0 μm.

[0023] Copper powder: Spherical powder prepared by gas atomization, with a median diameter D in its particle size distribution. 50 It has a diameter of 28.0 μm and a sphericity of ≥88%.

[0024] Titanium powder: prepared by hydrogenation-dehydrogenation (HDH) method, with a median particle size distribution D. 50 It is 18.0 μm.

[0025] 6013 aluminum alloy powder: spherical powder prepared by gas atomization, with a median diameter D in its particle size distribution. 50 The particle size is 38.0 μm, the sphericity is ≥92%, and the oxygen content is ≤800 ppm.

[0026] To strictly control the oxygen content, all titanium powder and copper powder were placed in an argon-protected drying oven (oxygen content < 50 ppm) and dried at 100°C for 1.5 h before use, and then naturally cooled to room temperature for later use.

[0027] 2. Stepwise mixing to prepare alloy powder Using a dual planetary mixer, 10mm diameter zirconia grinding balls were added, and the mixture was carried out in the following steps: S1. Preparation of the first premixed powder: The first titanium powder and all silicon carbide powder are premixed in a mixer. The mixing is carried out under argon protection, first running at a low speed of 80 r / min for 30 min, and then increasing to 180 r / min for 2.0 h to obtain the first premixed powder.

[0028] S2. Preparation of the second premixed powder: The second titanium powder is mixed with all the 6013 aluminum alloy powder in another mixer. First, it is run at 60 r / min for 30 min, and then the speed is increased to 200 r / min for 2.5 h to obtain the second premixed powder.

[0029] S3. Final Mixing: Place the first premixed powder, the second premixed powder, and the copper powder in a mixer. Add anhydrous ethanol at 0.15% of the mass of the silicon carbide powder as a dispersant. Run the mixer at 150 r / min for 3.0 h under a vacuum of ≤1 Pa to obtain aluminum alloy powder.

[0030] 3. Selective Laser Melting (SLM) Printing Printing was performed using an SLM device equipped with a 500W fiber laser under argon protection (oxygen content <50ppm). The substrate was preheated to 160°C, and the powder layer thickness was 30μm.

[0031] The key laser process parameters are: laser power 380W, scanning speed 1100mm / s, and scanning spacing 0.11mm. A 67° rotating island scanning strategy is adopted, with island size of 5mm×5mm, and the printed parts are obtained by printing layer by layer.

[0032] 4. Post-processing The following post-processing steps are performed on the printed parts to optimize performance: Stress-relief annealing: Hold at 300℃ for 2.0h, then cool with the furnace.

[0033] Artificial aging: Hold at 175℃ for 8.0 hours, then air cool after removal from the furnace.

[0034] After the above steps, an aluminum alloy printed part is obtained for subsequent performance testing.

[0035] Example 2-3 Examples 2-3 provide aluminum alloy powders for additive manufacturing and their preparation methods, and demonstrate the performance of parts printed from these powders.

[0036] The above embodiments have the same basic proportions as Embodiment 1, except for the amount of first titanium powder added, as detailed below: Example 2: The aluminum alloy powder comprises the following components in parts by weight: 6013 aluminum alloy powder: 100 parts by weight Silicon carbide powder: 4.3 parts by weight Copper powder: 1.6 parts by weight First titanium powder: 0.5 parts by weight Second titanium powder: 1.2 parts by weight, The mass ratio of the first titanium powder to the silicon carbide powder is approximately 0.116:1.

[0037] Example 3: The aluminum alloy powder comprises the following components in parts by weight: 6013 aluminum alloy powder: 100 parts by weight Silicon carbide powder: 4.3 parts by weight Copper powder: 1.6 parts by weight First titanium powder: 1.0 part by weight, Second titanium powder: 1.2 parts by weight, The mass ratio of the first titanium powder to the silicon carbide powder is approximately 0.233:1.

[0038] In the above embodiments, all other process parameters are exactly the same as in Embodiment 1.

[0039] Comparative Examples 1-3 Comparative Examples 1-3 provide aluminum alloy powders for additive manufacturing and their preparation methods, and demonstrate the performance of parts printed from these powders.

[0040] The specific differences between the above comparative examples and Example 1 are as follows: Comparative Example 1: A dual planetary mixer was used, with 10mm diameter zirconia grinding balls added. No stepwise premixing was performed; instead, a single final mixing was conducted. The specific steps are as follows: All silicon carbide powder, copper powder, titanium powder, and 6013 aluminum alloy powder were added to a mixer at once. Anhydrous ethanol, at 0.15% of the mass of the silicon carbide powder, was added as a dispersant. Mixing was carried out under argon protection (oxygen content <50ppm) at a speed of 120 rpm for 5.0 hours to obtain aluminum alloy powder.

[0041] The parameters of this one-time mixing process (120 r / min, 5.0 h) are set to conventional optimized conditions sufficient to ensure macroscopic uniform dispersion of the powder, in order to simulate the typical mechanical mixing method described in the background art.

[0042] Its powder composition is as follows: The aluminum alloy powder comprises the following components in parts by weight: 6013 aluminum alloy powder: 100 parts by weight Silicon carbide powder: 4.3 parts by weight Copper powder: 1.6 parts by weight Titanium powder: 2.0 parts by weight Comparative Example 2: The aluminum alloy powder comprises the following components in parts by weight: 6013 aluminum alloy powder: 100 parts by weight Silicon carbide powder: 4.3 parts by weight Copper powder: 1.6 parts by weight First titanium powder: 0.2 parts by weight Second titanium powder: 1.2 parts by weight, The mass ratio of the first titanium powder to the silicon carbide powder is approximately 0.047:1.

[0043] Comparative Example 3: The aluminum alloy powder comprises the following components in parts by weight: 6013 aluminum alloy powder: 100 parts by weight Silicon carbide powder: 4.3 parts by weight Copper powder: 1.6 parts by weight First titanium powder: 1.4 parts by weight Second titanium powder: 1.2 parts by weight, The mass ratio of the first titanium powder to the silicon carbide powder is approximately 0.326:1.

[0044] In the above comparative examples, all other process parameters are exactly the same as in Example 1.

[0045] Performance testing and results 1. Detection Method The performance of the molded parts prepared by aluminum alloy powder printing using the above embodiments and comparative examples was tested. Mechanical properties, wear resistance, and density were tested using standard specimens machined from the printed parts. To comprehensively evaluate the material's toughness, plate-shaped simulated specimens with thin-walled structural features were additionally printed for impact resistance testing. Specific methods and results are as follows: Mechanical property testing: Standard tensile specimens were machined, and their tensile strength (Rm) and elongation after fracture (A) were determined. The surface hardness of the specimens was tested using a Brinell hardness tester.

[0046] Surface abrasion resistance test: A hard scaffold is used to scratch the sample surface under a constant load, and the maximum depth of the scratch is measured to characterize the material's scratch resistance.

[0047] Density test: The measured density of the sample was measured using the Archimedes displacement method, and its percentage relative to the theoretical density of the material was calculated.

[0048] Impact resistance test: The material was printed into a plate-shaped simulation part (size: 50mm×50mm×1.0mm) with typical thin-walled structural characteristics. It was dropped multiple times from a height of 1.2 meters, and the number of times it did not crack was recorded to evaluate the impact toughness of the material.

[0049] 2. Test Results The key performance test results of the printed parts obtained from each embodiment and comparative example are shown in Table 1 below: Table 1 Performance test results of aluminum alloy printed parts from the examples and comparative examples Based on the test results in Table 1, the analysis is as follows: By comparing Examples 1, 2, and 3, all of which employed a stepwise premixing process, it was found that the mass ratios of the first titanium powder to silicon carbide in all three examples—0.186:1, 0.116:1, and 0.233:1, respectively—all achieved good performance. With the increase in the proportion of the first titanium powder, the tensile strength of the printed parts increased from 428 MPa in Example 2 to 458 MPa in Example 1, and then to 472 MPa in Example 3; the elongation was 9.7%, 9.3%, and 8.6%, respectively, all remaining at a high level; the hardness also increased from 133 HB to 146 HB, and then to 154 HB; simultaneously, the surface scratch depth was optimized from 2.5 μm to 1.2 μm, and then reduced to 1.1 μm; and the density reached 99.38%, 99.42%, and 99.35%, respectively, all remaining at a high level. This set of examples demonstrates that performance can be controlled within a preferred ratio range, and Example 1, with a mass ratio of 0.186:1, achieves a comprehensive balance in terms of tensile strength, elongation, hardness, wear resistance, and toughness.

[0050] Example 1 was compared with Comparative Example 1, which had the same total composition but used a one-time mixing process. The tensile strength of Example 1 (458 MPa) and hardness (146 HB) were significantly higher than those of Comparative Example 1 (318 MPa and 97 HB), due to the strong interfacial bonding achieved through stepwise premixing. The scratch depth of Example 1 (1.2 μm) was significantly better than that of Comparative Example 1 (6.8 μm), indicating improved wear resistance. Example 1 passed all impact tests, while Comparative Example 1 only passed 7. Example 1 achieved improvements in strength, hardness, and elongation, demonstrating a synergistic improvement in strength and toughness. Furthermore, the high density of Example 1 (99.42%) also confirms the role of the stepwise mixing process in improving powder uniformity and printing quality.

[0051] Comparing Example 1 with Comparative Examples 2 and 3, Comparative Example 2 exhibited poor wear resistance due to insufficient interfacial modification of titanium, resulting in a scratch depth of 2.9 μm. Furthermore, its elongation of 7.4% was the lowest among all samples, indicating compromised toughness and significantly inferior overall performance compared to Example 1. Comparative Example 3, on the other hand, suffered from excessive first titanium powder, leading to powder agglomeration and a reduction in its density from 98.3% to the lowest level, thus affecting its overall performance. This indicates that when the mass ratio of first titanium powder to silicon carbide is outside the range of (0.1-0.3):1, both insufficient interfacial modification and deterioration in processability will result in shortcomings in key material properties, preventing the attainment of excellent overall performance.

[0052] In summary, the technical solution of this invention strengthens the interfacial bonding between the ceramic phase and the metal matrix through a stepwise premixing process and a quantitative design of a first titanium powder to silicon carbide mass ratio of (0.1-0.3):1. Example 1, as the preferred embodiment, fully demonstrates the comprehensive advantages of this solution in terms of tensile strength, elongation, wear resistance, excellent toughness, and high density, effectively overcoming the problem of weak interfacial bonding and meeting the stringent requirements of the high-end 3C industry for precision structural component materials.

[0053] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An aluminum alloy powder for additive manufacturing, characterized in that, The aluminum alloy powder comprises, by total mass, the following components: 2%-6% silicon carbide powder, 1%-2% copper powder, 0.5%-3% titanium powder, and the balance being 6013 aluminum alloy powder.

2. The aluminum alloy powder for additive manufacturing according to claim 1, characterized in that, The silicon carbide powder is spherical with a particle size of 5-12 μm.

3. The aluminum alloy powder for additive manufacturing according to claim 1, characterized in that, The copper powder has a particle size of 15-45 μm and a sphericity of ≥85%.

4. The aluminum alloy powder for additive manufacturing according to claim 1, characterized in that, The titanium powder has a particle size of 10-30 μm.

5. The aluminum alloy powder for additive manufacturing according to claim 1, characterized in that, The 6013 aluminum alloy powder is an atomized spherical powder with a particle size of 15-53μm and a sphericity ≥90%.

6. A method for preparing aluminum alloy powder for additive manufacturing, characterized in that, Includes the following steps: S1. Provide silicon carbide powder, copper powder, titanium powder and 6013 aluminum alloy powder according to any one of claims 1-5; S2. The first titanium powder and the silicon carbide powder are premixed to obtain the first premixed powder; S3. Mix the second titanium powder with the 6013 aluminum alloy powder to obtain the second premixed powder; S4. The first premixed powder, the second premixed powder and the copper powder are finally mixed to obtain the aluminum alloy powder for additive manufacturing.

7. The preparation method according to claim 6, characterized in that, The mass ratio of the first titanium powder to the silicon carbide powder is (0.1-0.3):

1.

8. The preparation method according to claim 6, characterized in that, The final mixing in step S4 is carried out under an inert atmosphere, which is a vacuum or argon atmosphere, and the vacuum degree during the mixing process is ≤1 Pa or the oxygen content is <50 ppm.

9. The preparation method according to claim 6, characterized in that, In step S4, anhydrous ethanol is added as a dispersant at a mass of 0.1%-0.2% of the silicon carbide powder.

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