A laser additive manufacturing process for high-strength large-size component forming

Abstract

The application provides a laser additive manufacturing process for high-strength large-size component forming, which comprises the following steps: dividing a three-dimensional component to be formed into a plurality of two-dimensional slice layers along a height direction; dividing each two-dimensional slice layer into a core and a periphery; performing laser directional energy deposition forming on the core by using core metal powder and a Gaussian laser; and performing laser directional energy deposition forming on the periphery by using peripheral metal powder coated with nano ceramic particles and a high-energy flat-top laser. The laser additive manufacturing process for high-strength large-size component forming in the embodiment of the application uses conventional metal powder and a Gaussian laser deposition process for the core, and uses nano ceramic coated powder and a flat-top laser to improve the performance of the periphery, without post-processing, and the strength, rigidity and low cost are considered.

Description

Technical Field

[0001] This invention relates to the field of laser additive manufacturing technology, and in particular to a laser additive manufacturing process for forming high-strength, large-size components. Background Technology

[0002] Laser-directed energy deposition is an additive manufacturing technology based on the principle of material "discrete-stacking" and is widely used in the forming of large-sized complex metal components.

[0003] In related technologies, Gaussian energy lasers are often used to melt gas-atomized metal powder. Due to the extremely high cooling temperature gradient of the molten pool, grains tend to elongate along the temperature gradient, forming columnar crystals. This results in the component being dominated by martensite, producing significant anisotropy and reducing toughness, making it difficult to simultaneously achieve high strength, high stiffness, and low-cost manufacturing. Although annealing or solution treatment can improve the component's performance, this significantly increases costs. Summary of the Invention

[0004] This invention provides a laser additive manufacturing process for forming high-strength, large-size components, which solves the shortcomings of existing technologies that make it difficult to balance high strength, high rigidity, and low-cost manufacturing, and achieves high-performance, low-cost forming of large-size components.

[0005] This invention provides a laser additive manufacturing process for forming high-strength, large-size components, comprising: The three-dimensional component to be formed is divided into multiple two-dimensional slice layers along the height direction; Each of the two-dimensional slice layers is divided into a core and a periphery; The core is formed by laser-directed energy deposition using core metal powder and a Gaussian laser. The outer metal powder with nano-ceramic particles coated on its surface is laser-directed energy deposition formed by using a high-energy flat-top laser.

[0006] In some embodiments, the peripheral metal powder is prepared by: removing the nano-ceramic particles from the metal ingot, melting the remaining metal ingot and atomizing it into a basic powder, and then using the removed nano-ceramic particles to perform fluidization coating treatment on the basic powder to form the peripheral metal powder.

[0007] In some embodiments, the core metal powder has the same chemical composition as the peripheral metal powder.

[0008] In some embodiments, the particle size of the core metal powder and the peripheral metal powder is 90μm-160μm.

[0009] In some embodiments, the number of the outer forming layers is 1 to 5.

[0010] In some embodiments, the core metal powder is prepared by: melting metal ingots to obtain liquid metal, using a gas atomization device to atomize the liquid metal into metal droplets, and after the metal droplets solidify, forming spherical or planetary metal powder as the core metal powder.

[0011] In some embodiments, the core of all the two-dimensional slice layers is formed first, and then the periphery is formed in sequence.

[0012] In some embodiments, each of the two-dimensional slice layers is formed sequentially, and in each of the two-dimensional slice layers, the core is formed first, and then the periphery is formed.

[0013] This invention presents a laser additive manufacturing process for forming high-strength, large-size components. By employing different powder and laser combinations in the core and periphery of the component, the core and periphery respectively assume the functions of structural support and performance enhancement. The core utilizes conventional processes to ensure controllable forming efficiency and cost. The periphery employs powder coated with nano-ceramic particles and a high-energy flat-top laser, which helps to control the solidification behavior of the molten pool, reduce the tendency to form columnar crystals, and improve the uniformity of the microstructure, thereby enhancing the mechanical properties of the component's surface. Since the high-performance region is limited to a few layers in the periphery, the overall residual stress level is low, avoiding the cracking risk that may arise from using special materials on a large scale. Simultaneously, this method directly optimizes the microstructure during the forming process, eliminating the need for subsequent annealing or solution treatment, reducing the complexity and cost of the manufacturing process, and contributing to achieving the manufacturing requirements of high strength, high stiffness, and low cost. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of the laser additive manufacturing process for forming high-strength, large-size components provided by the present invention.

[0016] Figure 2 This is a schematic diagram of the structure of a component in the laser additive manufacturing process for forming high-strength, large-size components provided by the present invention.

[0017] Figure 3 This is a schematic diagram of the core and periphery of a component in a laser additive manufacturing process for forming high-strength, large-size components, provided by the present invention.

[0018] Figure 4This is a schematic diagram of the structure of the peripheral metal powder in the laser additive manufacturing process for forming high-strength, large-size components provided by the present invention.

[0019] Figure label: 1. Three-dimensional component; 2. Two-dimensional slice layer; 3. Core; 4. Periphery; 5. Core metal powder; 6. Peripheral metal powder; 61. Basic powder; 62. Ceramic coating layer. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0021] The following is combined with Figures 1 to 4 This invention describes a laser additive manufacturing process for forming high-strength, large-size components.

[0022] like Figure 1 As shown, the laser additive manufacturing process for forming high-strength, large-size components according to an embodiment of the present invention includes: dividing the three-dimensional component 1 to be formed into multiple two-dimensional slice layers 2 along the height direction. Each two-dimensional slice layer 2 is divided into a core 3 and a periphery 4. Core metal powder 5 is used to perform laser-directed energy deposition forming on the core 3 with a Gaussian laser. Peripheral metal powder 6 with a surface coated with nano-ceramic particles is used to perform laser-directed energy deposition forming on the periphery 4 with a high-energy flat-top laser.

[0023] The core metal powder 5 is a conventional metal powder, while the outer metal powder 6 is a powder with nano-ceramic particles coated on its surface.

[0024] The specific working process of the laser additive manufacturing process for forming high-strength, large-size components according to embodiments of the present invention is as follows: First, as Figure 2 As shown, the three-dimensional component 1 to be manufactured is subjected to layering to obtain a series of two-dimensional slice layers 2 distributed along the height direction; subsequently, as... Figure 3 As shown, each slice is divided into regions to determine the core 3 and the periphery 4. During the forming process, the core metal powder 5 is first melted using a Gaussian laser to form the main body of the component. Then, in the periphery 4 region, the periphery metal powder 6 with nano-ceramic particles on the surface is melted using a high-energy flat-top laser to complete the deposition of the periphery 4 part.

[0025] The outer metal powder 6, which is fluidized and formed by high-energy flat-top laser, has a fine equiaxed crystal microstructure. Compared with casting, forging and traditional laser forming processes, its mechanical properties are significantly improved.

[0026] In related technologies, Gaussian energy lasers are often used to melt gas-atomized metal powder. Due to the extremely high cooling temperature gradient of the molten pool, grains tend to elongate along the temperature gradient, forming columnar crystals. This results in the component being dominated by martensite, producing significant anisotropy and reducing toughness, making it difficult to simultaneously achieve high strength, high stiffness, and low-cost manufacturing. Although annealing or solution treatment can improve the component's performance, this significantly increases costs.

[0027] This invention presents a laser additive manufacturing process for forming high-strength, large-size components. By employing different powder and laser combinations in the core (3) and periphery (4) of the component, the core (3) and periphery (4) respectively assume the functions of structural support and performance enhancement. The core (3) uses conventional processes to ensure controllable forming efficiency and cost. The periphery (4) utilizes powder coated with nano-ceramic particles and a high-energy flat-top laser, which helps to control the solidification behavior of the molten pool, reduce the tendency to form columnar crystals, and improve the uniformity of the microstructure, thereby enhancing the mechanical properties of the component's surface. Since the high-performance region is limited to several layers of the periphery (4), the overall residual stress level is low, avoiding the cracking risk that may arise from using special materials on a large scale. Simultaneously, this method directly optimizes the microstructure during the forming process, eliminating the need for subsequent annealing or solution treatment, reducing the complexity and cost of the manufacturing process, and contributing to achieving the manufacturing requirements of high strength, high stiffness, and low cost.

[0028] In some embodiments, the peripheral metal powder 6 is prepared by: removing nano-ceramic particles from the metal ingot, melting the remaining metal ingot and atomizing it to form a basic powder 61, and then using the removed nano-ceramic particles to perform fluidization coating treatment on the basic powder 61 to form the peripheral metal powder 6.

[0029] In this embodiment, such as Figure 4 As shown, nano-ceramic particles are first separated from the original metal ingot; then the metal ingot after removing the ceramic particles is remelted and a basic powder 61 is obtained through a gas atomization process; finally, the previously separated nano-ceramic particles are used as a coating material and uniformly attached to the surface of the basic powder 61 in a fluidized state to form a ceramic coating layer 62, thereby obtaining the outer metal powder 6.

[0030] The laser additive manufacturing process for forming high-strength, large-size components in this invention uses recycled nano-ceramic particles from the ingot for powder surface modification, avoiding the composition mismatch or interface contamination problems that may be introduced by adding foreign ceramic phases. At the same time, it makes the nano-ceramic particles more uniformly distributed on the powder surface, which helps to control the solidification structure during laser melting and inhibit columnar crystal growth.

[0031] In some embodiments, the core metal powder 5 and the peripheral metal powder 6 have the same chemical composition.

[0032] In this embodiment, the core metal powder 5 is obtained by directly melting and atomizing the original metal ingot containing nano-ceramic particles; while the outer metal powder 6 is obtained by melting and atomizing the remaining metal portion after removing the nano-ceramic particles from the original ingot to form a basic powder 61, and then recoating the surface of the basic powder 61 with the removed nano-ceramic particles. Although the processing methods are different, the metal composition of the two powders remains consistent.

[0033] The laser additive manufacturing process for forming high-strength, large-size components in this embodiment of the invention introduces surface functionalization treatment while ensuring that the core 3 and the outer periphery 4 have the same material composition. This can reduce the stress concentration at the interface caused by the difference in the thermal expansion coefficient or melting point of the materials, which is beneficial to improving the overall forming stability of the component and avoiding the heterogeneous interface from becoming a source of crack initiation.

[0034] In some embodiments, the particle size of the core metal powder 5 and the peripheral metal powder 6 is 90 μm-160 μm. For example, the particle size of the core metal powder 5 and the peripheral metal powder 6 is 90 μm, 120 μm, or 160 μm.

[0035] In this embodiment, the particle size range of both the core metal powder 5 and the peripheral metal powder 6 is controlled between 90 micrometers and 160 micrometers to meet the requirements of laser directional energy deposition process for powder flowability and spreadability.

[0036] In some embodiments, the number of forming layers of the outer periphery 4 is 1 to 5. For example, the number of layers of the outer periphery 4 is 1, 3, or 5.

[0037] The number of forming layers in the outer perimeter 4 refers to the number of times the material is deposited from the inside out on the cross-section of the component.

[0038] Traditional metal powder particles, after fluidized bed treatment and laser-directed energy deposition, have significantly improved mechanical properties, but brittle phases are easily formed within the components. If large-sized components are manufactured, they are prone to fracture due to residual stress accumulation.

[0039] The laser additive manufacturing process for forming high-strength, large-size components in this embodiment of the invention adopts a forming strategy with the core 3 as the main component and the periphery 4 as the auxiliary component. This limits the high-performance forming to a limited thickness of the component surface layer. While improving the impact resistance of the component surface layer, it effectively controls the distribution range of brittle phases and reduces the overall residual stress level. Thus, while avoiding fracture defects, it takes into account both the forming integrity and mechanical performance requirements of large-size components.

[0040] In some embodiments, the core metal powder 5 is prepared by: melting metal ingots to obtain liquid metal, using a gas atomization device to atomize the liquid metal into metal droplets, and after the metal droplets solidify, forming spherical or planetary metal powder as the core metal powder 5.

[0041] In this embodiment, the core metal powder 5 is prepared by a standard gas atomization process: after the metal ingot is melted into a liquid state, it is broken into fine droplets by high-pressure gas impact. The droplets solidify into near-spherical particles during the cooling process and are collected and used directly as core metal powder 5.

[0042] The laser additive manufacturing process for forming high-strength, large-size components according to the present invention uses conventional gas atomization to prepare core powder. The process is mature and low-cost, and the resulting powder has good flowability and packing density, which is suitable for the rapid cladding process of Gaussian laser, ensuring efficient and stable forming of the main body of the component.

[0043] In some embodiments, the core 3 of all two-dimensional slice layers 2 is formed first, and then each peripheral layer 4 is formed in sequence.

[0044] In this embodiment, the entire forming process is divided into two stages: the first stage is to complete the deposition of all core 3 regions layer by layer to form a complete core; the second stage is to deposit coating powder on the outer 4 regions layer by layer from the bottom layer to the top layer.

[0045] The laser additive manufacturing process for forming high-strength, large-size components according to the present invention adopts a staged forming strategy, which can reduce the frequent switching of the laser head between the core 3 and the periphery 4, reduce process complexity, and allow the core 3 to cool down fully without interference from the periphery 4, which helps to control overall heat accumulation and reduce the risk of deformation.

[0046] In some embodiments, each two-dimensional slice layer 2 is formed sequentially, and in each two-dimensional slice layer 2, the core 3 is formed first, and then the periphery 4 is formed.

[0047] In this embodiment, the forming is carried out layer by layer: after the core 3 of each two-dimensional slice layer 2 is deposited, the outer region 4 is deposited on the same layer immediately, and then the next layer is moved on, and the sequence is repeated.

[0048] The laser additive manufacturing process for forming high-strength, large-size components according to the embodiments of the present invention adopts a layer-by-layer "core first, then periphery" forming sequence, which is conducive to achieving good bonding between the core 3 and the periphery 4 in adjacent areas.

[0049] The laser additive manufacturing process for forming high-strength, large-size components according to the embodiments of the present invention can improve mechanical properties without solution treatment, and realize the low-cost manufacturing of high-strength, high-rigidity, large-size components.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A laser additive manufacturing process for forming high-strength, large-size components, characterized in that, include: The three-dimensional component to be formed (1) is divided into multiple two-dimensional slice layers (2) along the height direction; Each of the two-dimensional slice layers (2) is divided into a core (3) and a periphery (4); The core (3) is formed by laser-directed energy deposition using core metal powder (5) and a Gaussian laser. The outer metal powder (6) with nano-ceramic particles on its surface is laser-directed energy deposition formed on the outer periphery (4) using a high-energy flat-top laser.

2. The laser additive manufacturing process for forming high-strength, large-size components according to claim 1, characterized in that, The preparation method of the peripheral metal powder (6) is as follows: remove the nano-ceramic particles from the metal ingot, melt the remaining metal ingot and atomize it into a basic powder (61), and then use the removed nano-ceramic particles to perform fluidization coating treatment on the basic powder (61) to form the peripheral metal powder (6).

3. The laser additive manufacturing process for forming high-strength, large-size components according to claim 1, characterized in that, The core metal powder (5) has the same chemical composition as the peripheral metal powder (6).

4. The laser additive manufacturing process for forming high-strength, large-size components according to claim 1, characterized in that, The particle size of the core metal powder (5) and the peripheral metal powder (6) is 90μm-160μm.

5. The laser additive manufacturing process for forming high-strength, large-size components according to claim 1, characterized in that, The number of forming layers of the outer periphery (4) is 1 to 5.

6. The laser additive manufacturing process for forming high-strength, large-size components according to any one of claims 1-5, characterized in that, The preparation method of the core metal powder (5) is as follows: molten metal ingots are used to obtain liquid metal, and the liquid metal is atomized into metal droplets using a gas atomization device. After the metal droplets solidify, spherical or planetary metal powder is formed as the core metal powder (5).

7. The laser additive manufacturing process for forming high-strength, large-size components according to any one of claims 1-5, characterized in that, First, the core (3) of all the two-dimensional slice layers (2) is formed in sequence, and then the periphery (4) is formed in sequence.

8. The laser additive manufacturing process for forming high-strength, large-size components according to any one of claims 1-5, characterized in that, Each of the two-dimensional slice layers (2) is formed sequentially, and in each of the two-dimensional slice layers (2), the core (3) is formed first, and then the periphery (4) is formed.

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