Method for enhancing performance of 3D printing metal component based on large current density

Abstract

The invention belongs to the technical field of additive manufacturing, and particularly relates to a method for enhancing the performance of a 3D printing metal component based on large current density. According to the method, the high current density is applied in the 3D printing strengthening process, the microstructure of the metal component is modified through the Joule heating effect of the high-current-density direct current and the synergistic effect that the electric field force is rapidly loaded to the metal defect structure, the mechanical property of the additive manufacturing part is improved, and the application range of the additive manufacturing process is expanded. The process is suitable for various metal materials such as stainless steel, titanium alloy, nickel-based alloy and aluminum alloy, has a wide application range, and meets the strengthening requirements of different materials and workpieces.

Description

Technical Field

[0001] This invention belongs to the field of additive manufacturing technology, specifically relating to a method for enhancing the performance of 3D printed metal components based on high current density. Background Technology

[0002] With the rapid development of modern industry, metal components are increasingly widely used in critical fields such as aerospace, automobile manufacturing, marine engineering, and energy equipment. These demanding fields place extremely high demands on the mechanical properties and service life of metal components. However, in actual operation, metal components often have to withstand the combined effects of complex alternating stresses and harsh environmental media, making them prone to surface cracks and other damage defects. If these damages are not effectively repaired and strengthened in a timely manner, microcracks will continue to propagate, eventually leading to component failure and even serious safety accidents.

[0003] Currently, traditional strengthening methods for metal components mainly include welding, thermal spraying, and laser cladding. Although these technologies are used to some extent, they generally have limitations such as a wide heat-affected zone, limited strengthening precision, and low processing efficiency, making it difficult to meet the repair needs of high-precision, high-performance components.

[0004] In recent years, additive manufacturing technology, represented by 3D printing, has provided a new technological path for strengthening and repairing metal components due to its advantages such as high precision, high flexibility, and high material utilization. However, additive manufacturing technology itself still has certain problems in the process of preparing metal parts: the cooling rate of the molten pool is too fast, which can easily form coarse columnar crystal structures inside materials such as titanium alloys; at the same time, unmelted metal powder may remain in the process. These microstructural defects often result in the density and mechanical properties of the final formed parts being lower than those of traditional forgings, which restricts the further promotion and application of this technology in critical load-bearing components. Summary of the Invention

[0005] To address the technical problems of existing additive manufacturing technologies in the preparation of metal parts, such as excessively rapid cooling of the molten pool, which easily leads to the formation of coarse columnar crystal structures within the material and the presence of incompletely melted metal powder, resulting in low density and mechanical properties of the formed parts, this invention provides a method for enhancing the performance of 3D printed metal components based on high current density.

[0006] This invention modifies the microstructure of metal components by applying a high-current-density direct current (DC) during the 3D printing strengthening process. The synergistic effect of the Joule heating effect and the rapid loading of an electric field onto the defective metal structure utilizes this DC to generate rapid and uniform heat, promoting a quick annealing process that releases residual stress within the material. Simultaneously, the potential difference generated by the high current is rapidly applied to dislocations and grain boundaries, breaking up coarse columnar crystals and promoting the formation of equiaxed or twinned crystals, ultimately improving the density and mechanical properties of the metal component.

[0007] The purpose of this invention is to provide a method for enhancing the performance of 3D printed metal components based on high current density, comprising the following steps: Metal powder is melted and deposited layer by layer in a powder bed melting method to prepare a preliminary metal component. A direct current of 500A to 2000A is applied to the preliminary metal component to break up columnar crystals, form twins, and combine the incompletely melted powder with the preliminary metal component to obtain a 3D printed metal component.

[0008] Preferably, the DC processing time is 10 to 100 seconds.

[0009] Preferably, the fracture type of the 3D printed metal component is ductile fracture, and the fracture surface has dimples, tear ridges and cleavage surfaces.

[0010] Preferably, the particle size range of the metal powder is 1 μm to 100 μm.

[0011] Preferably, the metal powder is at least one of stainless steel, titanium alloy, nickel-based alloy and aluminum alloy.

[0012] Preferably, the heat source used in the powder bed melting method is a laser or an electron beam.

[0013] Preferably, the powder bed melting method adopts selective laser melting with a laser power of 1200W, a scanning speed of 8mm / s, and a thickness of 500μm for each layer of metal powder.

[0014] Compared with the prior art, the present invention has the following technical effects: 1. This invention modifies the microstructure of metal components by applying a high-current-density direct current during the 3D printing strengthening process. The Joule heating effect of the high-current-density direct current, combined with the synergistic effect of the electric field force rapidly loading the defective metal structure, is utilized. The Joule heating effect generates rapid and uniform heat energy, promoting a rapid annealing process that releases residual stress within the material. Simultaneously, the potential difference generated by the high current is rapidly applied to dislocations and grain boundaries, thereby breaking up coarse columnar crystals and promoting the formation of equiaxed or twinned crystals, ultimately improving the density and mechanical properties of the metal components.

[0015] 2. Compared to traditional pulsed current strengthening technology, the present invention has a higher current density, which can more efficiently promote the melting and microstructure modification of metal powder. It does not require a complex pulse control device, and the strengthening process is simple to operate. Furthermore, the application time of the high-current-density DC current is only 10 to 100 seconds, which can complete the component strengthening in a short time, significantly shortening the overall production cycle of additive manufacturing and improving production efficiency.

[0016] 3. This invention only requires the use of a low-voltage DC high-power power supply, has no special requirements for the rising and falling edges of the power supply, has low equipment investment costs, and is easy to maintain, making it suitable for industrial promotion.

[0017] 4. This invention leverages the layer-by-layer deposition characteristics of additive manufacturing to reduce material waste. It is applicable to various metal materials such as stainless steel, titanium alloys, nickel-based alloys, and aluminum alloys, meeting the strengthening needs of components in different fields. Furthermore, by applying a high current density during the 3D printing strengthening process, this invention effectively avoids defects such as porosity and inclusions, ensuring the consistency and reliability of the component's mechanical properties. The component's fracture mechanism can be transformed from brittle fracture to elastic fracture, with obvious dimple morphology, significantly improving toughness and tensile strength. Attached Figure Description

[0018] Figure 1 The tensile stress-strain curves of the 3D printed titanium alloy components of Example 1 and Comparative Example 1 are shown.

[0019] Figure 2 The tensile stress-strain curves of the 3D printed titanium alloy components of Example 2 and Comparative Example 1 are shown.

[0020] Figure 3 The tensile stress-strain curves of the 3D printed titanium alloy components of Example 3 and Comparative Example 1 are shown.

[0021] Figure 4 The SEM morphology of the fracture surface of the 3D printed titanium alloy component in Comparative Example 1 is shown in the tensile test.

[0022] Figure 5The tensile fracture surface SEM morphology of the 3D printed titanium alloy component under the process of Example 1 is shown.

[0023] Figure 6 The image shows the SEM morphology of the fracture surface of the 3D printed titanium alloy component under the process of Example 2.

[0024] Figure 7 The tensile fracture surface SEM morphology of the 3D printed titanium alloy component under the process of Example 3 is shown. Detailed Implementation

[0025] To enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0026] Unless otherwise specified, all reagents used in this invention are commercially available, and all methods used are conventional techniques in the art.

[0027] Example 1 A method for enhancing the performance of 3D printed metal components based on high current density includes the following steps: Titanium alloy powder with a particle size range of 1μm to 100μm was selected and dried in a vacuum drying oven at 100℃ for 2 hours to remove moisture and adsorbed impurities from the titanium alloy powder.

[0028] Laser selective melting technology was used, with a laser power of 1200W, a scanning speed of 8mm / s, and a layer thickness of 500μm. The dried titanium alloy powder was deposited layer by layer to form a preliminary titanium alloy component with dimensions of 200mm×300mm×500mm.

[0029] A 500A DC current was applied to the initially formed titanium alloy component for 10 seconds to obtain a 3D printed metal component.

[0030] Example 2 A method for enhancing the performance of 3D printed metal components based on high current density includes the following steps: The difference from Example 1 is as follows: The DC processing time is 50 seconds.

[0031] Titanium alloy powder with a particle size range of 1μm to 100μm was selected and dried in a vacuum drying oven at 100℃ for 2 hours to remove moisture and adsorbed impurities from the titanium alloy powder.

[0032] Laser selective melting technology was used, with a laser power of 1200W, a scanning speed of 8mm / s, and a layer thickness of 500μm. The dried titanium alloy powder was deposited layer by layer to form a preliminary titanium alloy component with dimensions of 200mm×300mm×500mm.

[0033] A 500A DC current was applied to the initially formed titanium alloy component for 50 seconds to obtain a 3D printed metal component.

[0034] Example 3 A method for enhancing the performance of 3D printed metal components based on ultra-high current density includes the following steps: The difference from Example 1 is as follows: The DC processing time is 100 seconds.

[0035] Titanium alloy powder with a particle size range of 1μm to 100μm was selected and dried in a vacuum drying oven at 100℃ for 2 hours to remove moisture and adsorbed impurities from the titanium alloy powder.

[0036] Laser selective melting technology was used, with a laser power of 1200W, a scanning speed of 8mm / s, and a layer thickness of 500μm. The dried titanium alloy powder was deposited layer by layer to form a preliminary titanium alloy component with dimensions of 200mm×300mm×500mm.

[0037] A 500A DC current was applied to the initially formed titanium alloy component for 100 seconds to obtain a 3D printed metal component.

[0038] Comparative Example 1 A method for preparing 3D printed metal components includes the following steps: Titanium alloy powder with a particle size range of 1μm to 100μm was selected and dried in a vacuum drying oven at 100℃ for 2 hours to remove moisture and adsorbed impurities from the titanium alloy powder.

[0039] Laser selective melting technology was used, with a laser power of 1200W, a scanning speed of 8mm / s, and a layer thickness of 500μm. The dried titanium alloy powder was deposited layer by layer to form a preliminary titanium alloy component with dimensions of 200mm×300mm×500mm.

[0040] The difference from Example 1 is that no direct current treatment was performed.

[0041] Tensile tests and fracture morphology analysis were performed on the reinforced 3D printed titanium alloy components obtained in Examples 1 to 3 and the 3D printed titanium alloy component obtained in Comparative Example 1.

[0042] like Figure 1As shown, the tensile strength of the 3D-printed titanium alloy component of Comparative Example 1 without DC current treatment is 682 MPa, and the elongation after fracture is less than 1%. The tensile strength of the 3D-printed titanium alloy component of Example 1 is 949 MPa, and the elongation after fracture is approximately 5%. Compared with Comparative Example 1, the overall mechanical properties of the 3D-printed titanium alloy component obtained after DC current treatment are improved.

[0043] like Figure 2 As shown, the 3D-printed titanium alloy component of Example 2, which was subjected to a 500A DC current treatment for 50 seconds, exhibited a tensile strength of 1081 MPa and an elongation after fracture of approximately 3.6%. Compared to Comparative Example 1, which was not subjected to DC current treatment, the comprehensive mechanical properties of the 3D-printed titanium alloy component obtained after DC current treatment were significantly improved.

[0044] like Figure 3 As shown, the 3D printed titanium alloy component of Example 3, which was subjected to a 500A DC current treatment for 100 seconds, had a tensile strength of 1226MPa and an elongation after fracture of about 3.4%. Compared with Comparative Example 1, which was not subjected to DC current treatment, the comprehensive mechanical properties of the 3D printed titanium alloy component obtained by DC current treatment were significantly improved.

[0045] like Figure 4 As shown, the tensile fracture surface of the 3D printed titanium alloy component of Comparative Example 1, which was not subjected to DC current treatment, is smooth, without obvious dimples, and contains unmelted spherical particles, indicating that the fracture type is brittle fracture.

[0046] like Figure 5 As shown, after a tensile test on the 3D printed titanium alloy component of Example 1, the tensile fracture surface showed a certain amount of dimples and a large number of tear ridges, as well as a large cleavage surface. The fracture type changed from brittle fracture to ductile fracture, and the fracture type was cleavage fracture, indicating that the modification effect was quite obvious.

[0047] like Figure 6 As shown, after the 3D printed titanium alloy component of Example 2 underwent a tensile test, its tensile fracture surface showed a large number of dimples, a small number of tear ridges, and a large cleavage surface. The fracture type was a mixed fracture of micropore aggregation fracture and cleavage fracture.

[0048] Figure 7 After a tensile test was conducted on the 3D-printed titanium alloy component of Example 3, a large number of dimples and tear ridges were found on its tensile fracture surface, and the fracture type was quasi-cleavage fracture.

[0049] Table 1 Mechanical property data of 3D printed titanium alloy components of Examples 1-3 and Comparative Example 1 " / " indicates that no DC power processing was performed.

[0050] As shown in Table 1, with the increase of current application time, the tensile strength and elongation after fracture of the 3D printed titanium alloy component were improved. Compared with the comprehensive mechanical properties of the 3D printed titanium alloy component of Comparative Example 1 without DC current treatment, the comprehensive mechanical properties of the three embodiments were improved.

[0051] It should be noted that when numerical ranges are involved in this invention, it should be understood that the two endpoints of each numerical range, as well as any value between the two endpoints, can be selected. Since the steps and methods used are the same as in the embodiments, preferred embodiments are described in this invention to avoid redundancy. Although preferred embodiments of this invention have been described, those skilled in the art, once they understand the basic inventive concept, can make other changes and modifications to these embodiments, and all such changes and modifications fall within the scope of this invention.

[0052] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. If these modifications and variations fall within the scope of equivalents of this invention, then this invention also intends to include these modifications and variations.

Claims

1. A method for enhancing the performance of 3D printed metal components based on high current density, characterized by, The method comprises the following steps: a preliminary formed metal component is prepared by melting and accumulating metal powder layer by layer through a powder bed melting method; a direct current treatment with a current of 500A-2000A is applied to the preliminary formed metal component to break columnar crystals, form twin crystals, and combine the incompletely melted powder with the preliminary formed metal component, thereby obtaining a 3D printed metal component.

2. The method of claim 1, wherein, The time of the direct current treatment is 10-100 seconds.

3. The method for enhancing the performance of 3D printed metal components based on high current density according to claim 1, characterized in that, The particle size of the metal powder ranges from 1μm to 100μm.

4. The method of claim 1, wherein, The metal powder is at least one of stainless steel, titanium alloy, nickel-based alloy and aluminum alloy.

5. The method of claim 1, wherein, The heat source used in the powder bed melting method is a laser or an electron beam.

6. The method for enhancing the performance of 3D printed metal components based on high current density according to claim 5, characterized in that, The powder bed melting method uses laser selective melting, the laser power is 1200W, the scanning speed is 8mm / s, and the laying thickness of each layer of metal powder is 500μm.

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