A method for performance regulation of additive manufacturing of aluminum-silicon alloy

Abstract

This invention discloses a method for performance control of additively manufactured aluminum-silicon alloys, belonging to the field of aluminum alloy additive manufacturing technology. The method includes the following steps: S1: preparing Al-Si alloy powder; S2: forming a component from the Al-Si alloy powder using selective laser melting; S3: subjecting the component to direct aging heat treatment. This invention improves the microstructure of additively manufactured Al-Si alloys through direct aging heat treatment, thereby improving the alloy's thermal conductivity while imparting superior mechanical strength. This method can be used to solve the current heat dissipation problems of high-power devices and is of great significance for the development of efficient and lightweight heat sinks and their application in aerospace, automotive, and other related fields.

Description

Technical Field

[0001] This invention belongs to the field of aluminum alloy additive manufacturing technology, and specifically relates to a method for performance control of additive manufacturing aluminum-silicon alloys. Background Technology

[0002] With the acceleration of industrialization and the continuous increase in the power density of electronic devices, the heat dissipation of instruments and equipment faces greater challenges. However, due to the limitations of traditional manufacturing methods such as casting and machining, the complex structural design of heat sinks is restricted, making it difficult to further improve heat dissipation efficiency. Metal additive manufacturing technology brings greater freedom to the lightweight design and manufacturing of heat sinks, and is particularly suitable for the forming and preparation of complex structures such as irregular shapes, integrated structures, and lattice structures.

[0003] Thermal conductivity and strength are two key performance indicators in radiator design; although thermal conductivity is generally considered the primary material property determining radiator performance, mechanical strength is even more important in additive manufacturing applications. High mechanical strength not only ensures the stability of the radiator under various mechanical stresses but also allows for thinner wall thickness designs. This design can increase the heat exchange area and shorten the heat transfer path, significantly improving the overall performance of the radiator.

[0004] Aluminum alloys are used as thermal conductive materials due to their low density, high specific strength, corrosion resistance, and excellent electrical and thermal conductivity. The 6063 wrought aluminum alloy, commonly used in current thermal management structures, has a thermal conductivity of approximately 200 W / (m·K) at room temperature, but its additive manufacturing formability is poor. In contrast, eutectic / near-eutectic aluminum-silicon alloys exhibit good processability through selective laser melting (SLM) and are widely used in additive manufacturing. The unique non-equilibrium solidification of SLM results in excellent mechanical strength in Al-Si alloys, but their thermal conductivity is significantly lower than that of cast alloys of the same composition, and they also generate substantial residual stress. Currently, components are typically subjected to T6 or annealing followed by heat treatment.

[0005] However, both of the aforementioned heat treatments destroy the network structure characteristics produced by selective laser melting, significantly reducing mechanical strength and thus affecting the use of thin-walled heat sinks. Balancing the thermal conductivity and mechanical strength of the alloy is a crucial issue currently facing lightweight and efficient heat sinks. Summary of the Invention

[0006] In order to overcome the above-mentioned shortcomings in the prior art, the present invention aims to provide a method for performance control of additive manufacturing aluminum-silicon alloys, so as to solve the problem that it is difficult to balance thermal conductivity and mechanical strength in the prior art.

[0007] To achieve the above objectives, the present invention employs the following technical solution: A method for performance control of additive manufacturing aluminum-silicon alloys includes the following steps: S1: Preparation of Al-Si alloy powder; S2: Based on the Al-Si alloy powder, a component is formed using a selective laser melting process; S3: Perform aging heat treatment on the component.

[0008] A further improvement of the present invention is that: Preferably, in S1, the Al-Si alloy powder composition, by mass percentage, is: Si content 9-11 wt%, Mg content 0.20-0.45 wt%, Fe content ≤0.55 wt%, Mn content ≤0.45 wt%, and the balance is Al.

[0009] Preferably, in S1, Al-Si alloy powder is prepared using a vacuum atomization process.

[0010] Preferably, in S1, the particle size of the Al-Si alloy powder is 15µm-53µm.

[0011] Preferably, in S2, during the selective laser melting process, the laser power is 330-350W and the laser scanning speed is 1300-1500mm / s.

[0012] Preferably, in S2, during the selective laser melting process, the laser scanning spot spacing is 0.12-0.14 mm; the spot diameter is 0.08 mm.

[0013] Preferably, in S2, during the selective laser melting process, the height of the formed layer is 0.03 mm; and the scanning path adopts a unidirectional scanning path.

[0014] Preferably, in S2, the substrate preheating temperature is 80°C during the selective laser melting process.

[0015] Preferably, in S3, the direct aging heat treatment involves placing the component in a heat-holding furnace and heating it at a temperature of 180℃-200℃ for 8-10 hours, followed by air cooling to room temperature.

[0016] Preferably, the tensile strength of Al-Si alloy components after direct aging heat treatment is 350-410 MPa, and the thermal conductivity reaches 160-175 W / (m·K).

[0017] Compared with the prior art, the present invention has the following beneficial effects: This invention discloses a method for performance control of additive manufacturing aluminum-silicon alloys. The method first prepares Al-Si alloy powder according to the target composition, then fabricates components from the Al-Si alloy powder using selective laser melting (SLM), and directly performs aging heat treatment on the components. This method combines SLM with heat treatment technology, reducing residual stress generated during forming by increasing the substrate preheating temperature and providing an ideal deposited microstructure for subsequent heat treatment steps. Common annealing and T6 heat treatments typically destroy the network structure of the deposited alloy and form large polygonal Si particles, thus significantly impairing the alloy's mechanical properties. This invention employs a direct aging heat treatment process, which effectively preserves the network structure generated during SLM forming and promotes the precipitation of solid solution atoms, reducing the negative impact on the alloy's thermal conductivity. Through this optimized treatment, the alloy's mechanical strength is maintained at a high level, while its thermal conductivity is significantly improved, thus meeting the requirements of relevant engineering applications. Attached Figure Description

[0018] Figure 1 Secondary electron images of Al-Si alloys deposited by selective laser melting, provided as an example of the present invention.

[0019] Figure 2 Low-magnification secondary electron images of the direct-aging state of Al-Si alloys formed by selective laser melting, provided as an example of the present invention.

[0020] Figure 3 High-magnification secondary electron images of the direct aging state of Al-Si alloys formed by selective laser melting, provided as an example of the present invention.

[0021] Figure 4 The room temperature tensile stress-strain curves of Al-Si alloys in the deposited state and the direct aging state provided for examples of the present invention via selective laser melting are shown. Detailed Implementation

[0022] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0023] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”

[0024] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0025] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0026] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.

[0027] This invention discloses a method for performance control of additive manufacturing aluminum-silicon alloys, the method comprising the following steps: S1: Preparation of hypoeutectic Al-Si alloy powder; The composition of Al-Si alloy powder, by mass percentage, includes 9–11 wt% Si; 0.20–0.45 wt% Mg; ≤0.55 wt% Fe; ≤0.45 wt% Mn; with the balance being Al.

[0028] Al-Si alloy powders were prepared using a vacuum atomization process. The particle size of the Al-Si alloy powders ranged from 15 μm to 53 μm. The powder preparation was carried out under vacuum or inert gas protection to avoid alloy oxidation and contamination. The molten alloy was rapidly cooled and solidified into tiny particles by high-pressure gas spraying, forming Al-Si alloy powders of the desired particle size. The particle size range of 15 μm to 53 μm was controlled, which is beneficial for subsequent selective laser melting processes, ensuring good powder flowability and spreadability, as well as the density and precision after melting.

[0029] S2: The hypoeutectic Al-Si alloy powder is used to form components by selective laser melting process; The selective laser melting process parameters are as follows: laser power is 330-350W; laser scanning speed is 1300-1500mm / s; laser scanning spot spacing is 0.12-0.14mm; forming layer height is 0.03mm; spot diameter is 0.08mm; and the scanning path adopts a unidirectional scanning path.

[0030] In this process, limiting the laser power ensures sufficient energy input to melt the powder while avoiding defects caused by overheating. Limiting the laser scanning speed controls the melting rate and cooling rate, affecting the microstructure and properties of the component.

[0031] Preferably, the substrate preheating temperature during the selective laser melting process is 80°C.

[0032] S3: Perform direct aging heat treatment on the component.

[0033] The direct aging heat treatment process parameters are: holding at 180℃-200℃ for 8-10 hours, followed by air cooling to room temperature. Direct aging heat treatment is a heat treatment process that improves the microstructure and properties of alloys by heating and holding at that temperature for a period of time, followed by natural cooling to room temperature. This step is particularly crucial for Al-Si alloy components prepared by SLM, as it effectively releases residual stress generated during the printing process, promotes the formation of precipitates, thereby improving strength and hardness while maintaining good thermal conductivity.

[0034] After aging heat treatment, the final microstructure still retains the characteristics of the deposited network structure. This network structure is mainly composed of Al-Si eutectic phases, and its morphology presents as a dense or dispersed elongated network structure. These network structures divide the Al matrix into multiple regions, thus forming a unique microstructure. Due to its role in hindering dislocations, the network structure helps to improve the tensile strength of the alloy.

[0035] The tensile strength of Al-Si alloy components after direct aging heat treatment is 350-410 MPa, while the thermal conductivity reaches 160-175 W / (m·K).

[0036] The following description, in conjunction with specific embodiments, provides further details.

[0037] Example 1 A method for controlling the thermal conductivity of additively manufactured hypoeutectic Al-Si alloys includes the following steps: S1: Hypoeutectic Al-Si alloy powder was prepared by vacuum atomization. The composition of the obtained hypoeutectic Al-Si alloy powder was as follows (by mass percentage): 10.06 wt% Si, 0.311 wt% Mg, 0.082 wt% Fe, 0.01 wt% Mn, with the balance being Al. The particle size of the obtained hypoeutectic Al-Si alloy powder was 13 μm-53 μm.

[0038] S2: Selective laser melting process is used to form components from the above-mentioned hypoeutectic Al-Si alloy powder; during the selective laser melting process, the selected laser power is 340W; the laser scanning speed is 1400mm / s; the laser scanning spot spacing is 0.13mm; the forming layer height is 0.03mm; the spot diameter is 0.08mm; the scanning path adopts a unidirectional scanning path; the substrate preheating temperature is 80℃.

[0039] S3: The formed component was subjected to direct aging heat treatment; the selected direct aging heat treatment process parameters were: holding at 200℃ for 10 hours, followed by air cooling to room temperature. The tensile strength and thermal conductivity of the alloy in the direct-aged state were 350 MPa and 173.7 W / (m·K), respectively.

[0040] See Figure 1 The microstructure characteristics of aluminum-silicon alloy deposited by selective laser melting are shown in the figure. The dark α-Al matrix and the gray eutectic Si phase distributed in a network around the matrix are visible.

[0041] See Figure 2 and Figure 3 The microstructure changes of aluminum-silicon alloys formed by selective laser melting at different magnifications after direct aging treatment are shown. After aging heat treatment, the network structure of the alloy is still retained, and granular and rod-shaped nanoscale precipitates formed by the desolvation of Si elements appear in the α-Al matrix. The desolvation of Si elements effectively reduces the lattice distortion of the α-Al matrix, thereby improving the thermal conductivity of the alloy.

[0042] See Figure 4 The figures show the room temperature tensile stress-strain curves of the deposited and directly aged alloys in Example 1. Due to the network structure and the presence of nano-precipitates, good alloy tensile strength can still be obtained.

[0043] Example 2 A method for controlling the thermal conductivity of additively manufactured hypoeutectic Al-Si alloys includes the following steps: S1: Hypoeutectic Al-Si alloy powder was prepared by vacuum atomization. The composition of the obtained hypoeutectic Al-Si alloy powder was as follows (by mass percentage): 10.06 wt% Si, 0.311 wt% Mg, 0.082 wt% Fe, 0.01 wt% Mn, with the balance being Al. The particle size of the obtained hypoeutectic Al-Si alloy powder was 13 μm-53 μm.

[0044] S2: Selective laser melting process is used to form components from the above-mentioned hypoeutectic Al-Si alloy powder; during the selective laser melting process, the selected laser power is 340W; the laser scanning speed is 1400mm / s; the laser scanning spot spacing is 0.13mm; the forming layer height is 0.03mm; the spot diameter is 0.08mm; the scanning path adopts a unidirectional scanning path; the substrate preheating temperature is 80℃.

[0045] S3: The formed component was subjected to direct aging heat treatment; the selected direct aging heat treatment process parameters were: holding at 180℃ for 10 hours, followed by air cooling to room temperature. The tensile strength and thermal conductivity of the alloy in the direct-aged state were 399 MPa and 163.8 W / (m·K), respectively.

[0046] Example 3 A method for controlling the thermal conductivity of additively manufactured hypoeutectic Al-Si alloys includes the following steps: S1: Hypoeutectic Al-Si alloy powder was prepared by vacuum atomization. The composition of the obtained hypoeutectic Al-Si alloy powder was as follows (by mass percentage): 10.06 wt% Si, 0.311 wt% Mg, 0.082 wt% Fe, 0.01 wt% Mn, with the balance being Al. The particle size of the obtained hypoeutectic Al-Si alloy powder was 13 μm-53 μm.

[0047] S2: Selective laser melting process is used to form components from the above-mentioned hypoeutectic Al-Si alloy powder; during the selective laser melting process, the selected laser power is 340W; the laser scanning speed is 1400mm / s; the laser scanning spot spacing is 0.13mm; the forming layer height is 0.03mm; the spot diameter is 0.08mm; the scanning path adopts a unidirectional scanning path; the substrate preheating temperature is 80℃.

[0048] S3: The formed component was subjected to direct aging heat treatment; the selected direct aging heat treatment process parameters were: holding at 180℃ for 8 hours, followed by air cooling to room temperature. The tensile strength and thermal conductivity of the alloy in the direct-aged state were 409 MPa and 160.4 W / (m·K), respectively.

[0049] Example 4 A method for controlling the thermal conductivity of additively manufactured hypoeutectic Al-Si alloys includes the following steps: S1: Hypoeutectic Al-Si alloy powder was prepared by vacuum atomization. The composition of the obtained hypoeutectic Al-Si alloy powder was as follows (by mass percentage): 10.06 wt% Si, 0.311 wt% Mg, 0.082 wt% Fe, 0.01 wt% Mn, with the balance being Al. The particle size of the obtained hypoeutectic Al-Si alloy powder was 13 μm-53 μm.

[0050] S2: Selective laser melting process is used to form components from the above-mentioned hypoeutectic Al-Si alloy powder; during the selective laser melting process, the selected laser power is 340W; the laser scanning speed is 1400mm / s; the laser scanning spot spacing is 0.13mm; the forming layer height is 0.03mm; the spot diameter is 0.08mm; the scanning path adopts a unidirectional scanning path; the substrate preheating temperature is 80℃.

[0051] S3: The formed component was subjected to direct aging heat treatment; the selected direct aging heat treatment process parameters were: holding at 190℃ for 10 hours, followed by air cooling to room temperature. The tensile strength and thermal conductivity of the alloy in the direct-aged state were 378 MPa and 168.8 W / (m·K), respectively.

[0052] Example 5 A method for controlling the thermal conductivity of additively manufactured hypoeutectic Al-Si alloys includes the following steps: S1: Hypoeutectic Al-Si alloy powder was prepared by vacuum atomization. The composition of the obtained hypoeutectic Al-Si alloy powder was as follows (by mass percentage): 10.06 wt% Si, 0.311 wt% Mg, 0.082 wt% Fe, 0.01 wt% Mn, with the balance being Al. The particle size of the obtained hypoeutectic Al-Si alloy powder was 13 μm-53 μm.

[0053] S2: Selective laser melting process is used to form components from the above-mentioned hypoeutectic Al-Si alloy powder; during the selective laser melting process, the selected laser power is 330W; the laser scanning speed is 1300mm / s; the laser scanning spot spacing is 0.12mm; the forming layer height is 0.03mm; the spot diameter is 0.08mm; the scanning path adopts a unidirectional scanning path; the substrate preheating temperature is 80℃.

[0054] S3: The formed component was subjected to direct aging heat treatment; the selected direct aging heat treatment process parameters were: holding at 190℃ for 8 hours, followed by air cooling to room temperature. The tensile strength and thermal conductivity of the alloy in the direct-aged state were 388 MPa and 164.6 W / (m·K), respectively.

[0055] Example 6 A method for controlling the thermal conductivity of additively manufactured hypoeutectic Al-Si alloys includes the following steps: S1: Hypoeutectic Al-Si alloy powder was prepared by vacuum atomization. The composition of the obtained hypoeutectic Al-Si alloy powder was as follows (by mass percentage): 10.06 wt% Si, 0.311 wt% Mg, 0.082 wt% Fe, 0.01 wt% Mn, with the balance being Al. The particle size of the obtained hypoeutectic Al-Si alloy powder was 13 μm-53 μm.

[0056] S2: Selective laser melting process is used to form components from the above-mentioned hypoeutectic Al-Si alloy powder; during the selective laser melting process, the selected laser power is 350W; the laser scanning speed is 1500mm / s; the laser scanning spot spacing is 0.14mm; the forming layer height is 0.03mm; the spot diameter is 0.08mm; the scanning path adopts a unidirectional scanning path; the substrate preheating temperature is 80℃.

[0057] S3: The formed component was subjected to direct aging heat treatment; the selected direct aging heat treatment process parameters were: holding at 200℃ for 8 hours, followed by air cooling to room temperature. The tensile strength and thermal conductivity of the alloy in the direct-aged state were 364 MPa and 170.2 W / (m·K), respectively.

[0058] Example 7 A method for controlling the thermal conductivity of additively manufactured hypoeutectic Al-Si alloys includes the following steps: S1: Hypoeutectic Al-Si alloy powder was prepared by vacuum atomization. The composition of the obtained hypoeutectic Al-Si alloy powder was as follows (by mass percentage): 10.06 wt% Si, 0.311 wt% Mg, 0.082 wt% Fe, 0.01 wt% Mn, with the balance being Al. The particle size of the obtained hypoeutectic Al-Si alloy powder was 13 μm-53 μm.

[0059] S2: Selective laser melting process is used to form components from the above-mentioned hypoeutectic Al-Si alloy powder; during the selective laser melting process, the selected laser power is 330W; the laser scanning speed is 1400mm / s; the laser scanning spot spacing is 0.14mm; the forming layer height is 0.03mm; the spot diameter is 0.08mm; the scanning path adopts a unidirectional scanning path; the substrate preheating temperature is 80℃.

[0060] S3: The formed component underwent direct aging heat treatment. The selected direct aging heat treatment process parameters were: holding at 200℃ for 9 hours, followed by air cooling to room temperature. The tensile strength and thermal conductivity of the alloy in the directly aged state were 354 MPa and 171.3 W / (m·K), respectively. (350 MPa and 173.7 W / (m·K) 358 MPa and 170.2 W / (m·K) The above description is merely an 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. A method for performance control of additive manufacturing aluminum-silicon alloys, characterized in that, Includes the following steps: S1: Prepare Al-Si alloy powder; the Al-Si alloy powder has the following composition by mass percentage: Si content 9-11 wt%, Mg content 0.20-0.45 wt%, Fe content ≤0.55 wt%, Mn content ≤0.45 wt%, and the balance is Al; S2: Based on the Al-Si alloy powder, a selective laser melting process is used to form a component; during the selective laser melting process, the laser power is 330-350W; the laser scanning speed is 1300-1500mm / s; During selective laser melting, the substrate preheating temperature is 80℃; During selective laser melting, the laser scanning spot spacing is 0.12-0.14 mm; the spot diameter is 0.08 mm; the forming layer height is 0.03 mm; and a unidirectional scanning path is used. S3: Perform direct aging heat treatment on the component; The direct aging heat treatment involves placing the component in a holding furnace and heating it at a holding temperature of 180℃-200℃ for 8-10 hours, followed by air cooling to room temperature. The tensile strength of Al-Si alloy components after direct aging heat treatment is 350-410 MPa, and the thermal conductivity reaches 160-175 W / (m·K). The aluminum-silicon alloy has a network structure, which is mainly composed of Al-Si eutectic phase and its morphology is a dense or dispersed elongated network structure.

2. The method for performance control of additive manufacturing aluminum-silicon alloys according to claim 1, characterized in that, In S1, Al-Si alloy powder is prepared using a vacuum atomization process.

3. The method for performance control of additive manufacturing aluminum-silicon alloys according to claim 2, characterized in that, In S1, the particle size of the Al-Si alloy powder is 15µm-53µm.

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