Method and device for controlling the microstructure and properties of alloy components for additive manufacturing

Abstract

The present disclosure provides a method and apparatus for controlling the microstructure and properties of alloy components for additive manufacturing. According to the performance requirements of the alloy component at different locations to be manufactured, the fusion layer used to form the alloy component is divided into performance regions and the target grain characteristics required for each performance region are determined. According to the target grain characteristics, each performance region is divided into a grid shape consisting of multiple sub-regions, and each performance region is set to have a different sub-region size. According to a preset scanning path, a high-energy beam is controlled to sequentially fill and scan the corresponding positions of each sub-region on the powder layer one by one to form a fusion layer with different grain characteristics in each performance region. This makes it possible to achieve grain characteristics that match the required performance in different regions of the alloy component. By adjusting the sub-region size, especially without changing the scanning parameters, only by adjusting the sub-region size, the formation of target grain characteristics such as polycrystalline structure, polycrystalline layered structure, and oriented columnar crystals can be achieved.

Description

Technical Field

[0001] The present disclosure relates to the field of additive manufacturing, and more particularly to a multi-model driven powder bed additive manufacturing method and apparatus. Background Art

[0002] Powder bed additive manufacturing, such as Laser Powder Bed Fusion (LPBF), uses a laser beam to melt and solidify powdered material layer by layer, enabling the manufacture of high-precision parts with complex geometries. This technology offers unique advantages in the manufacture of alloy components, such as reduced material waste, shorter production cycles, and lightweight designs.

[0003] During additive manufacturing, the material's grain characteristics significantly impact the mechanical properties of the final product. For example, grain size and morphology influence the material's strength, ductility, fatigue resistance, and oxidation resistance. Therefore, different components have varying requirements for grain characteristics depending on their operating environment and mechanical requirements.

[0004] For example, nickel-based superalloys, due to their exceptional high-temperature performance, are often used in critical components such as turbine disks and blades in aircraft engines and turbines. These components are subject to complex loads during service, placing extremely high demands on the material's mechanical properties. Turbine disks are subject to multiaxial stresses, requiring an equiaxed grain structure to ensure isotropic performance. Turbine blades, on the other hand, are primarily subject to uniaxial stresses and often require oriented grains, such as single crystals or columnar crystals, to meet high-temperature strength requirements in a specific direction. Currently, there are published reports on grain control in nickel-based superalloys produced by LPBF. These methods employ process parameter adjustments, such as laser power, scanning speed, and scanning spacing, to produce a melt pool with a high depth-to-width ratio at a high energy density, promoting an equiaxed grain structure. Heat treatment is employed to achieve an isotropic grain structure through recrystallization. Interlayer-selective scanning strategies are employed to reduce crystal texture in nickel-based superalloys. Finally, alloy composition design involves the addition of rare earth elements to achieve a grain structure with a high equiaxed fraction.

[0005] However, most existing technologies rely on complex process parameter adjustments or post-processing processes to achieve the regulation of grain characteristics. These methods usually involve the precise control of multiple variables, such as laser power, scanning speed, scanning spacing, etc., to form a specific molten pool morphology and cooling rate, thereby affecting the growth and arrangement of grains. In addition, additional heat treatment may be required after manufacturing to recrystallize or optimize the microstructure of the material. These operations are often cumbersome, increasing the complexity of the process, and the effect may also be limited by the mutual influence of various process parameters. It is difficult to achieve uniform and precise grain control in different areas, resulting in inconsistent performance of the final product or difficulty in meeting the expected standards. Summary of the Invention

[0006] The present disclosure proposes a method and device for controlling the microstructure and properties of alloy components for additive manufacturing, which can achieve grain characteristics matching the required performance in different regions of the alloy component. By adjusting the sub-region size, especially without changing the scanning parameters, different grain characteristics can be formed by adjusting the sub-region size alone.

[0007] A first aspect of the present disclosure provides a method for controlling the microstructure and properties of alloy components for additive manufacturing, wherein the additive manufacturing utilizes a high-energy beam to selectively melt powder layers applied layer by layer to manufacture the alloy component. The method comprises: dividing one or more fusion layers used to form the alloy component into performance regions according to the performance requirements of the alloy component at different positions and determining the target grain characteristics required for each performance region; dividing each performance region into a grid shape consisting of a plurality of sub-regions according to the target grain characteristics and setting each performance region to have a different sub-region size; and controlling the high-energy beam to sequentially fill and scan the corresponding positions of each sub-region on the powder layer according to a preset scanning path to form the one or more fusion layers having different grain characteristics in each performance region.

[0008] According to a preferred embodiment of the first aspect, the filling scan of each sub-region by the high-energy beam is set to have the same scanning parameters.

[0009] According to a preferred embodiment of the first aspect, the scanning parameters include one or more of scanning power, scanning rate, layer thickness, scanning spacing, scanning trajectory and inter-layer rotation degree.

[0010] According to a preferred embodiment of the first aspect, the target grain characteristics include at least two of single crystal structure, polycrystalline structure, polycrystalline layered structure, oriented columnar crystals and equiaxed crystals.

[0011] According to a preferred embodiment of the first aspect, when the target grain characteristics are polycrystalline structure, polycrystalline layered structure and oriented columnar crystal, the sub-region size of the performance region corresponding to the polycrystalline structure is smaller than the sub-region size of the performance region corresponding to the polycrystalline layered structure, and the sub-region size of the performance region corresponding to the polycrystalline layered structure is smaller than the sub-region size of the performance region corresponding to the oriented columnar crystal.

[0012] According to a preferred embodiment of the first aspect, the width of the sub-region of the polycrystalline structure corresponding to the performance region is 200 to 400 μm.

[0013] According to a preferred embodiment of the first aspect, the method further includes: adjusting the size of the sub-region so that the molten pool generated during the scanning process merges along the scanning spacing direction to form a molten pool similar in size and shape to the sub-region, so as to refine the grains and weaken the texture.

[0014] According to a preferred embodiment of the first aspect, the method further comprises: dividing at least one performance region into a plurality of performance gradient regions and setting each performance gradient region to have a gradually varying sub-region size.

[0015] According to a preferred embodiment of the first aspect, the division of the multiple performance gradient regions includes: dividing the at least one performance region within the cross section to achieve a grain characteristic gradient distribution between the same levels, and / or, superimposing and dividing the at least one performance region layer by layer in the longitudinal direction corresponding to the multiple fusion layers to achieve a grain characteristic gradient distribution between different levels.

[0016] According to a preferred embodiment of the first aspect, when forming the performance region of the oriented columnar crystals, the method further comprises: adjusting the incident angle of the high-energy beam so that the growth direction of the oriented columnar crystals is consistent with the solidification direction of the molten pool.

[0017] A second aspect of the present disclosure provides an alloy component obtained by the method described in any one of the first aspects.

[0018] A third aspect of the present disclosure provides a device for controlling the organizational properties of alloy components manufactured by additive manufacturing, wherein the additive manufacturing utilizes a high-energy beam to selectively melt powder layers applied layer by layer to manufacture the alloy components, and the device comprises: a performance region division module, configured to divide the performance regions of one or more fusion layers used to form the alloy component according to the performance requirements of the alloy component at different positions to be manufactured; a target grain feature determination module, configured to determine the target grain features required for each performance region according to the performance requirements; a sub-region division module, configured to divide each performance region into a grid shape consisting of multiple sub-regions according to the target grain features and set each performance region to have a different sub-region size; and a scanning control module, configured to control the high-energy beam to fill and scan the corresponding positions of each sub-region on the powder layer one by one according to a preset scanning path to form the one or more fusion layers with different grain features in each performance region. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate one or more embodiments of the disclosure and, together with the description, serve to explain the principles of the disclosure and to enable one of ordinary skill in the relevant art to make and use the disclosure.

[0020] Figure 1 FIG2 shows a schematic diagram of sub-region division of an alloy component according to an embodiment of the present disclosure;

[0021] Figure 2A schematic diagram of different sub-region width scanning strategies according to an embodiment of the present disclosure is shown;

[0022] Figure 3 The cross-sectional grain characteristic morphology of the nickel-based high-temperature alloy sample obtained according to Comparative Example 1 is shown;

[0023] Figure 4 shows the morphology of the molten pool of the nickel-based high-temperature alloy sample obtained according to Example 1;

[0024] Figure 5 The topography of the cross-section grain characteristics of the nickel-based high-temperature alloy sample obtained according to Example 1 is shown;

[0025] Figure 6 shows a morphology of the cross-sectional grain characteristics of the nickel-based high-temperature alloy sample obtained according to Example 1.1;

[0026] Figure 7 Shows the morphology of the cross-sectional grain characteristics of the nickel-based high-temperature alloy specimens obtained according to Comparative Example 2 (top) and Example 2 (bottom);

[0027] Figure 8 Shows the morphology of the cross-sectional grain characteristics of the nickel-based high-temperature alloy specimens obtained according to Comparative Example 3 (top) and Example 3 (bottom);

[0028] Figure 9 The tensile properties curves of the nickel-based high-temperature alloy samples obtained according to Comparative Example 2 and Example 2 at room temperature are shown;

[0029] Figure 10 A schematic diagram of a structure and performance control device for additively manufacturing alloy components according to the present disclosure is shown;

[0030] Figure 11 A schematic diagram of a framework of an electronic device according to the present disclosure is shown. DETAILED DESCRIPTION

[0031] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments may be implemented in a variety of forms and should not be construed as limited to the examples set forth herein; rather, the description of these embodiments is intended to make this disclosure more comprehensive and complete and to fully convey the concepts of the example embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to provide a deeper understanding of the embodiments of the present disclosure.

[0032] The term "additive manufacturing" as used in this disclosure refers to 3D printing technology, which creates three-dimensional objects by adding powdered materials layer by layer and melting them with a high-energy beam (such as a laser or electron beam). This technology uses digital models generated by computer-aided design (CAD) software to precisely control the melting and solidification of powdered materials, thereby building complex three-dimensional objects layer by layer. In practical applications, these three-dimensional objects can be functional parts, structural components, tools, or any other physical objects, and their design and manufacturing can be customized to the specific needs of their end use.

[0033] The "alloy components" referred to in this disclosure are metal or metal-matrix composite components manufactured using additive manufacturing techniques for various engineering and industrial applications. Alloy components can be made from a single type of alloy powder or from a blend of multiple alloy powders to create components with specific mechanical and chemical properties.

[0034] The "fused layers" referred to in this disclosure are cross-sectional layers of metal or alloy formed by melting and solidifying powdered material layer by layer. Each fused layer represents a cross-section of a component and forms the basis of its final geometry and internal structure. As the high-energy beam sweeps through and melts the powdered material layer by layer, these fused layers gradually accumulate, ultimately forming a complete three-dimensional object.

[0035] The present disclosure provides a method for regulating the microstructure and properties of an alloy component during additive manufacturing, which is also a method for additive manufacturing of an alloy component. The method mainly includes two stages: a process configuration stage and a forming and construction stage.

[0036] During the process configuration phase, the performance regions of one or more fusion layers used to form the alloy component are first divided according to the performance requirements of the alloy component at different locations. Then, for each performance region, the target grain characteristics required are determined. Based on these target grain characteristics, each performance region is further divided into a grid consisting of multiple sub-regions, and different sub-region sizes are set for each performance region. During the forming and construction phase, the high-energy beam is controlled according to the preset scanning path to fill and scan the corresponding positions of each sub-region on the powder layer one by one to form the one or more fusion layers with different grain characteristics in each performance region. Powder is spread and scanned layer by layer to obtain other fusion layers, and finally the desired alloy component is formed.

[0037] In order for the final manufactured alloy components to meet their functional requirements in actual applications, it is first necessary to analyze the performance required of the components at different locations, including a comprehensive understanding of the working environment of the components, the mechanical loads they are subjected to, thermal loads, corrosion resistance, and other specific requirements. For example, for turbine disks used in aircraft engines, which operate in high-temperature and high-pressure environments, the outer edge needs to have high heat resistance and creep resistance, while the inner edge requires higher toughness and fatigue resistance. Based on these performance requirements at different locations, the performance zones of the components at different locations can be reasonably divided, and the target grain characteristics required for each performance zone can be further determined.

[0038] Figure 1 A schematic diagram illustrates the sub-regional division of an alloy component according to an embodiment of the present disclosure. This division is crucial for microstructural control during additive manufacturing. After determining the performance requirements for alloy component 11 at different locations, its 3D model is first sliced ​​to obtain fused layers 11A-11E. It should be noted that these fused layers are merely examples and do not reflect the full number of layers involved in an actual manufacturing process.

[0039] After obtaining these fusion layers, all or part of the layers covered by them in the fusion layers 11A-11E are divided into performance regions according to the performance requirements distribution of the alloy component 11. Taking the fusion layer 11A as an example, the division results for the fusion layer 11A are Figure 1 The first performance region 12A, the second performance region 12B and the third performance region 13B are shown, and it is determined that the first performance region 12A corresponds to the first target grain characteristic, the second performance region 12B corresponds to the second target grain characteristic, and the third performance region 12C corresponds to the third target grain characteristic.

[0040] After determining these performance regions and their corresponding target grain characteristics, each performance region is further divided into a grid structure consisting of multiple sub-regions. For example, each performance region of the fusion layer 11A is divided into multiple sub-regions, that is, the first performance region 12A is divided into sub-regions 12A1-12A n The second performance area 12B is divided into sub-areas 12B1-12B n The third performance area 12C is divided into sub-areas 12C1-12C nThe structure is constructed such that different sub-region sizes are set for each performance region. For example, the grid width of the first performance region 12A is set to W1, the grid width of the second performance region 12B is set to W2, and the grid width of the third performance region 12C is set to W3. The sizes of these sub-regions can be set according to the desired grain characteristics, thereby achieving microstructural control within different performance regions through filling scanning with a high-energy beam during the additive manufacturing process.

[0041] Figure 2 Schematic diagram of different sub-area width scanning strategies according to an embodiment of the present disclosure is shown. Figure 2 In the example of FIG. 5 , the sub-region width of the first performance region 12A is set to 200 μm, the sub-region width of the second performance region 12B is set to 500 μm, and the sub-region width of the third performance region 12C is set to 1400 μm.

[0042] During the forming and construction phase, the high-energy beam is controlled to sequentially scan and fill the corresponding locations 12A-12C on the powder layer according to a preset scanning path, forming a fused layer 12A-12C with different grain characteristics. The order in which these areas are scanned is not fixed and depends on the specific path design. The high-energy beam can scan sub-area 12A first, or 12B or 12C first, as long as all sub-areas are ultimately uniformly filled. This scanning sequence optimizes forming efficiency and material utilization without affecting the final grain characteristics, ensuring that areas with different grain characteristics are formed within the same layer, thereby meeting the performance requirements of the alloy component at different locations.

[0043] In the description of "the high-energy beam being controlled to sequentially scan and fill the corresponding positions 12A-12C on the powder layer according to a preset scanning path," it should be understood that the setting of the preset scanning path is not limited to any specific regular pattern. Although in traditional laser powder bed fusion (LPBF) processes, the scanning path is usually performed in a certain order, such as a linear arrangement from left to right or from top to bottom, in actual applications, especially to optimize microstructural properties and reduce residual stress, the scanning path can adopt a random scanning order, so that the high-energy beam scans these sub-areas in an irregular order during the process of filling and scanning the positions on the powder layer one by one, thereby reducing heat concentration and improving the quality of the final formed part. In addition, the random scanning order can also break up the periodic texture structure that may be formed in the component, making the grain structure of the material more refined and uniform.

[0044] The target grain characteristics of this disclosure encompass a variety of grain structure types to meet the requirements of different performance regions, including, for example, at least two of single crystal, polycrystalline, polycrystalline lamellar, oriented columnar, and equiaxed grains. By combining these multiple grain characteristics, this disclosure enables targeted microstructural shaping within different performance regions, thereby producing alloy components with complex performance requirements.

[0045] Specifically, a single crystal structure is characterized by a near-invisible grain boundary, offering excellent high-temperature performance and creep resistance, making it suitable for applications requiring high-temperature strength and fatigue resistance. A polycrystalline structure consists of multiple randomly oriented grains, each with a regular atomic arrangement within it, but with some dislocation at the grain boundaries. This polycrystalline structure enables the material to absorb energy under load through slip at grain boundaries and deformation within the grains, resulting in a good balance of strength and toughness. This makes it suitable for applications requiring a balance between load-bearing capacity and impact resistance. A polycrystalline lamellar structure, based on a polycrystalline structure, features a layered grain arrangement, enabling a gradual change in properties between layers, providing excellent crack growth resistance within the material and making it suitable for critical areas requiring crack growth resistance. Directed columnar crystals, characterized by grains growing in a specific direction, exhibit excellent creep resistance and are commonly used in applications requiring high creep resistance, such as components subject to prolonged high-temperature loads. Equiaxed crystals, composed of isotropic grains, exhibit consistent properties in all directions, making them suitable for applications requiring uniform mechanical properties.

[0046] The shape of the sub-regions divided by the present disclosure (i.e., the shape of the grid) can be selected according to the performance requirements of the alloy component, including but not limited to squares, rectangles, and other possible polygonal or curved boundary shapes. Preferably, it is a square, because the square sub-region is simpler in scanning path planning and energy distribution control, and can maintain the uniformity of temperature and energy input within each sub-region, so as to better achieve uniform grain growth and consistent microstructure. In addition, the size of the sub-region (such as the size of the square sub-region is expressed as the sub-region width) can also be adjusted according to specific performance requirements, for example, according to the required grain characteristics, heat conduction path, uniformity of energy input, and geometric accuracy of the final component.

[0047] In some embodiments, the filling and scanning process of the high-energy beam adopted in the present disclosure for each sub-region is set to have the same scanning parameters. The scanning parameters include, but are not limited to, various parameters such as scanning power (e.g., laser power), scanning rate, layer thickness, scanning pitch, scanning trajectory (e.g., serpentine trajectory scanning), and interlayer rotation degree (e.g., 90° interlayer rotation). These parameters remain unchanged throughout the scanning process so that the energy input and heat conduction applied by the high-energy beam to each sub-region are consistent. Adjusting the scanning parameters is a traditional method to achieve different grain characteristics in the fusion layer. The present disclosure provides a new process method, that is, under the same scanning parameters, different grain characteristics can be obtained only by adjusting the size of the sub-region. This simplifies the manufacturing process and also improves the manufacturing efficiency, providing a more efficient implementation method for manufacturing complex alloy components with various grain characteristics.

[0048] In some embodiments, when the target grain characteristics are polycrystalline structure, polycrystalline layered structure, and directional columnar crystal, the size of the sub-region corresponding to the performance region of the polycrystalline structure is smaller than the size of the sub-region corresponding to the performance region of the polycrystalline layered structure, and the size of the sub-region corresponding to the performance region of the polycrystalline layered structure is smaller than the size of the sub-region corresponding to the performance region of the directional columnar crystal. For example, when the target grain characteristic corresponding to the first performance region 12A is polycrystalline structure, the target grain characteristic corresponding to the second performance region 12B is polycrystalline layered structure, and the target grain characteristic corresponding to the third performance region 12C is directional columnar crystal, the width of the sub-region 12A1 - 12A n is set to be smaller than the width of the sub-region 12B1 - 12B n and the width of the sub-region 12B1 - 12B n is set to be smaller than the width of the sub-region 12C1 - 12C n , that is, W1 < W2 < W3. Among them, in order to ensure that polycrystalline structure can be formed, W1 is set to be 200 to 400 μm.

[0049] The implementation and effect verification of the present invention are further described below based on detailed embodiments.

[0050] To verify the influence of sub-region division on the microstructure and properties of nickel-based superalloys, the following comparative examples and embodiments all select nickel-based superalloy specimens as the objects for additive manufacturing. By weight percentage, the powder purity ≥ 99.9%. The composition table of the powder raw materials used is as follows (excluding inevitable impurities):

[0051]

[0052] Comparative Example 1

[0053] The obtained powder feedstock was placed in a laser powder bed fusion (LPBF) apparatus with settings of 250 W laser power, 600 mm / s scan rate, 100 μm scan pitch, 40 μm layer thickness, and a serpentine trajectory scan with 90° rotation between layers. Under these process conditions, additive manufacturing was performed directly without subdividing the component model, ultimately resulting in a nickel-based superalloy specimen.

[0054] Example 1

[0055] The obtained powder feedstock was placed in an LPBF machine with settings of 250 W laser power, 600 mm / s scan rate, 100 μm scan pitch, and 40 μm layer thickness. A serpentine trajectory was used for scanning, with 90° rotation between layers. The specimen model was then divided into three sub-regions (square grids) of varying widths, with sub-region widths set to 200 μm, 500 μm, and 1400 μm, respectively. After completing the settings, printing was initiated to obtain a nickel-based superalloy specimen.

[0056] Example 1.1

[0057] Example 1.1 uses the same process parameters as Example 1, except that, in Example 1.1, sub-regions (square grids) of different widths are divided in multiple regions of the sample model at the same time, and the sub-region widths are set to 200 μm, 500 μm, 600 μm, 1000 μm and 1400 μm, respectively.

[0058] Comparative Example 2

[0059] The obtained powder feedstock was placed in an LPBF machine with settings of 160 W laser power, 1310 mm / s scan rate, 76 μm scan pitch, 40 μm layer thickness, a serpentine scanning trajectory, and 90° rotation between layers. Under these process conditions, additive manufacturing was performed directly without subdividing the component model, ultimately resulting in a nickel-based superalloy specimen.

[0060] Example 2

[0061] The obtained powder feedstock was placed in an LPBF machine with settings of 160 W laser power, 1310 mm / s scan rate, 76 μm scan pitch, 40 μm layer thickness, a serpentine scanning trajectory, and 90° inter-layer rotation. Three regions within the specimen model were divided into sub-regions (square grids) of varying widths, with sub-region widths set to 200 μm, 500 μm, and 1400 μm, respectively. After completing the settings, printing was initiated to produce a nickel-based superalloy specimen.

[0062] Comparative Example 3

[0063] The obtained powder feedstock was placed in an LPBF machine with settings of 255 W laser power, 960 mm / s scan rate, 60 μm scan pitch, 40 μm layer thickness, a serpentine scanning trajectory, and 90° rotation between layers. Under these process conditions, additive manufacturing was performed directly without subdividing the component model, ultimately resulting in a nickel-based superalloy specimen.

[0064] Example 3

[0065] The obtained powder feedstock was placed in an LPBF machine with settings of 255 W laser power, 960 mm / s scan rate, 60 μm scan pitch, 40 μm layer thickness, serpentine scanning, and 90° inter-layer rotation. Three regions within the specimen model were divided into sub-regions (square grids) of varying widths, with sub-region widths set to 200 μm, 500 μm, and 1400 μm, respectively. After completing the settings, printing was initiated to produce a nickel-based superalloy specimen.

[0066] Figure 3 The characteristic morphology of the cross-section grain of the nickel-based high-temperature alloy sample obtained according to Comparative Example 1 is shown. In this morphology, it can be observed that the growth direction of the grains is relatively consistent. This is mainly because under the conventional scanning strategy, the molten pool always moves along the speed direction of the laser scanning, resulting in the stability of the heat flow direction. Due to the stability of the heat flow direction, the growth of the grains is also relatively consistent, showing a relatively uniform epitaxial growth pattern. The interface between the grains is relatively obvious, and the overall structure appears to be orderly, but there is also a lack of fine grain formation. This phenomenon shows that the heat flow field under the conventional scanning strategy changes little and the convection intensity is weak, so it will not significantly induce the diversification of grain morphology.

[0067] Figure 4 The following image shows the morphology of the melt pool of a nickel-based superalloy sample obtained according to Example 1. In this example, a sub-region scanning strategy was employed, with the sub-region width set to 200 μm. Under these conditions, the laser scanned the adjacent pass after completing one pass within a sub-region before the melt pool had fully solidified. This resulted in the two adjacent melt pools merging to form a single, larger melt pool approximately 200 μm wide. Figure 4 The melt pool morphology in the image shows that the melt pool is in a state of constant dynamic change from formation to final solidification, with complex variations in the heat flow direction. Compared to conventional scanning, the application of the sub-region partitioning strategy eliminates the shared preferred growth direction of grains within the large melt pool, thereby increasing the diversity of the grain structure.

[0068] Figure 5The topography of the cross-section grain characteristics of the nickel-based high-temperature alloy sample obtained according to Example 1 is shown. In this topography, the influence of the complex thermal flow field caused by the sub-region division strategy on the grain growth direction can be observed. Specifically, Figure 5 The grain growth direction shown in the figure is not consistent, and there is a clear difference in grain orientation at the edge and center of the molten pool. This phenomenon is consistent with the Walton and Chalmers competitive growth selection model. At the edge of the large molten pool, due to the arc shape of the molten pool boundary, the grain orientation deviates from the original grain orientation. <001> The grains in the direction will grow first, while in the center of the molten pool, the grains can grow along <001> direction, and eventually formed a polycrystalline layered structure.

[0069] Figure 6 The morphology of the cross-section grain characteristics of the nickel-based superalloy sample obtained according to Example 1.1 is shown. In this example, the sub-region width is increased to 500 μm, and the width of the molten pool is also increased accordingly. Under this condition, the heat flow direction in the center of the large molten pool tends to be consistent, and the grains can grow epitaxially along the construction direction, with the crystal orientation being <001> However, at the edge of the large molten pool, due to the arc shape of the molten pool boundary, the growth direction of the grains will deviate, resulting in differences in the grain orientation between the center and the edge, thus forming a polycrystalline layered structure. It is worth noting that as the width of the sub-region further increases to 1400 μm, the characteristics of the molten pool gradually disappear, and the grains begin to show a clear directional columnar structure, such as Figure 5 shown.

[0070] Figure 7 Figures 2 and 3 show the morphology of the cross-sectional grain characteristics of nickel-based superalloy specimens obtained according to Comparative Example 2 (top) and Example 2 (bottom). In Comparative Example 2, a conventional scanning strategy was adopted, resulting in more pronounced epitaxial growth of the grains and a more consistent preferred growth direction of the grains. In Example 2, however, due to the application of the sub-region partitioning strategy, convection within the molten pool was intensified, leading to the formation of a large number of fine grains. This phenomenon indicates that under a complex thermal flow field, convection in the melt significantly affects the morphology of the grains, thereby enhancing the fine-grained characteristics of the material.

[0071] Figure 8 Figures show the cross-sectional grain characteristics of nickel-based superalloy specimens obtained according to Comparative Example 3 (top) and Example 3 (bottom). In Comparative Example 3, the conventional scanning strategy limited grain growth and blocked epitaxial growth. However, in Example 3, the complex thermal flow field and enhanced melt convection induced by the sub-area division scanning strategy led to heterogeneous nucleation and the formation of a large number of fine grains, especially near the edge of the melt pool, where the number of fine grains increased significantly. Figure 8The significant effects of different scanning strategies on the characteristic morphology of grains are clearly shown, demonstrating the advantages of the sub-region division strategy in controlling grain growth direction and grain refinement.

[0072] Figure 9 The following figure shows the tensile properties of nickel-based superalloy samples obtained according to Comparative Example 2 and Example 2 at room temperature. The yield strength of the Comparative Example 2 sample was 885 MPa, the tensile strength was 1191 MPa, and the elongation was 35%. This indicates that under the conventional scanning strategy, the sample has high ductility but low yield strength. However, after adopting the scanning strategy of Example 2, the yield strength of the sample increased significantly to 993 MPa, the tensile strength increased slightly to 1193 MPa, and the elongation decreased significantly to 12%. This change in performance can be attributed to the fine grain structure introduced by the scanning strategy in Example 2, which increases the material's strength but sacrifices ductility. Specifically, a fine grain structure generally increases the number of grain boundaries, hindering dislocation motion and thus improving the material's strength, but it also reduces the material's plastic deformation capacity, which explains the decrease in elongation. By comparing the performance of the two samples, it can be seen that the scanning strategy of Example 2 effectively optimizes the sample's mechanical properties, particularly improving the yield strength, which is of great significance for improving the load-bearing capacity of nickel-based superalloys in practical applications.

[0073] As can be seen, the disclosed microstructure and property control method effectively controls the microstructure of nickel-based superalloys by adjusting the sub-region width without changing other scanning parameters. Specifically, by controlling the sub-region width, a variety of different crystal structures can be formed under the same process conditions, significantly improving the applicability of superalloys in different application scenarios.

[0074] In some embodiments of the present disclosure, the method for regulating microstructure and properties further involves adjusting the size of the sub-region so that the molten pool generated during the scanning process merges along the scanning spacing direction to form a molten pool similar in size and shape to the sub-region, so as to refine the grains and weaken the texture.

[0075] Specifically, by controlling the size of the subregions, for example, the morphology and behavior of the melt pool during scanning can be influenced, causing it to merge along the scanning pitch. This merging effect is achieved by rationally designing the size and shape of the subregions, so that the melt pool matches the size and shape of the pre-defined subregions. This merging of the melt pools facilitates grain refinement and texture weakening. When the melt pools merge during scanning, the close proximity of the melt pool size to the subregions promotes uniform cooling and solidification within the melt pool, resulting in finer grains. A finer grain structure typically significantly improves the mechanical properties of the material, such as increasing its strength and toughness. Furthermore, the uniform cooling environment created by the merging melt pools also helps to weaken the material's texture effects and reduce the impact of anisotropy on mechanical properties. This allows for optimal control of the material's microstructure simply by adjusting the subregion size, without changing other parameters such as scanning speed and laser power.

[0076] In some embodiments of the present disclosure, the tissue performance regulation method further optimizes the microstructure and mechanical properties of the material, for example, by dividing the performance area to form multiple performance gradient areas, so that the sub-area sizes within them have gradually changing characteristics, thereby achieving a gradual grain structure and performance performance in different parts of the material.

[0077] Specifically, the division of performance gradient regions can be adjusted in two dimensions. First, within the cross-section, at least one performance region can be divided to achieve a gradient distribution of grain characteristics within the same layer. In this case, as the sub-region size gradually changes, the molten pool morphology and cooling rate within different sub-regions also change accordingly, thereby generating a microstructure with different grain characteristics. This gradient distribution can achieve a gradual change in mechanical properties within the same layer and optimize the local performance of the material in different parts. Second, in the longitudinal direction, a gradient distribution of grain characteristics between different layers can be achieved by stacking and dividing multiple fused layers layer by layer. In this case, the sub-region size of each layer can be gradually changed from bottom to top, thereby forming a gradient microstructure between different fused layers. This longitudinal gradient distribution can effectively adjust the mechanical properties of the material in the thickness direction, so that it has targeted optimized structural characteristics at different levels, such as exhibiting different strength and toughness in areas subjected to different stresses.

[0078] By combining these two gradient zoning methods, the present disclosure enables highly customized material grain characteristics and properties, providing an effective technical approach for manufacturing complex, multi-performance high-temperature alloy components. This not only improves the overall performance of the material, but also optimizes fatigue resistance, creep resistance, and high-temperature resistance within specific regions.

[0079] In some embodiments of the present disclosure, in order to optimize the formation effect of oriented columnar crystals, the microstructure and performance control method can also adjust the incident angle of the high-energy beam so that the growth direction of the oriented columnar crystals is consistent with the solidification direction of the molten pool.

[0080] Specifically, in the process of melt manufacturing using, for example, a laser, the morphology and solidification process of the molten pool have a direct impact on the direction of crystal growth. In order to form directional columnar crystals, it is generally required that the growth direction of the crystal is consistent with the cooling direction of the molten pool (i.e., the solidification direction). However, in actual processing, due to the limitations of equipment settings or process parameters, the incident angle of the high-energy beam may deviate from the solidification direction of the molten pool, resulting in a shift in the crystal growth direction, affecting the final columnar crystal orientation and uniformity. In order to solve this problem, the present disclosure can control the incident angle of the high-energy beam to match the solidification direction of the molten pool. For example, according to the shape of the molten pool and the expected growth direction of the columnar crystal, the inclination angle of the high-energy beam relative to the workpiece surface is adjusted to ensure that the heat input of the laser is more evenly distributed in the molten pool, thereby promoting the gradual cooling of the molten pool along a predetermined direction and guiding the crystal to grow along this direction to form ideal directional columnar crystals. This will not only be conducive to the formation of directional columnar crystals with excellent mechanical properties, but also can reduce the number of grain boundaries and reduce the defect density in the material, thereby improving the strength, ductility and high temperature resistance of the material.

[0081] It should be understood that the various processes and steps described above can be implemented by configuring the functional modules of the tissue performance control device (i.e., the additive manufacturing device). Although the specific content of the method has been described in detail, in order to more clearly understand the core part of the tissue performance control device involved in the present disclosure, the following is combined with Figure 10 A brief introduction to its main components is given. Figure 10 A schematic diagram of a framework of a microstructure and property control device for additively manufacturing alloy components according to the present disclosure is shown.

[0082] In some embodiments, the tissue performance control device 20 involved in the present disclosure includes a performance region division module 21 , a target grain feature determination module 22 , a sub-region division module 23 and a scanning control module 24 .

[0083] The performance region division module 21 is configured to divide one or more fusion layers used to form the alloy component into performance regions according to performance requirements of the alloy component at different positions.

[0084] The target grain characteristic determination module 22 is configured to determine the target grain characteristics required for each performance region according to the performance requirements.

[0085] The sub-region division module 23 is configured to divide each performance region into a grid shape consisting of a plurality of sub-regions according to the target grain characteristics and set each performance region to have a different sub-region size.

[0086] The scanning control module 24 is configured to control the high-energy beam to sequentially fill and scan the positions of the sub-regions corresponding to the powder layer according to a preset scanning path to form the one or more fused layers with different grain characteristics in each performance region.

[0087] It should be noted that although the above detailed description mentions several modules that constitute the tissue performance control device 20, this division is not mandatory. In fact, according to embodiments of the present disclosure, the features and functions of two or more modules described above can be embodied in a single module. Conversely, the features and functions of a single module described above can be further divided and embodied by multiple modules.

[0088] Figure 11 A schematic diagram of the framework of an electronic device according to the present disclosure is shown. In some embodiments, the electronic device 30 includes a processor 31 and a memory 32 (wherein the number of the processor 31 and the memory 32 can be one or more). The memory 32 is coupled to the processor 31 and is used to store instructions executed by the processor 31. When executed by the processor 31, the instructions cause the electronic device 30 to perform any of the tissue performance control methods described above.

[0089] Specifically, the processor 31 communicates with the memory 32, and the memory 32 may include a read-only memory and a random access memory to provide instructions and data to the processor 31. In addition, a part of the memory 32 may also include a non-volatile random access memory (NVRAM). In the memory 32, operation instructions, executable modules, data structures or their subsets, or even their extended sets are stored. These operation instructions cover various operations and are used to implement various operations. The organizational performance control method described in the embodiment of the present disclosure can be applied to the processor 31, or implemented by the processor 31. The processor 31 can be any applicable computer processor, such as a central processing unit (CPU), a graphics processing unit (GPU), a programmable logic device (FPGA), etc. In the embodiment of the present disclosure, the processor 31 is responsible for executing each step of the organizational performance control method.

[0090] In some embodiments, the present disclosure further provides a computer-readable storage medium storing a computer program, which, when executed by the processor 31, implements the tissue performance control method described in any of the foregoing items. Specifically, a computer-readable storage medium refers to a medium that can be read by a computer system, such as a hard disk, a solid-state drive, an optical disk, a flash drive, etc. In some embodiments of the present disclosure, a computer-readable storage medium stores a set of computer programs, which are executed by the processor 31 to implement the various steps and functions described in the tissue performance control method. These computer programs may include operating systems, embedded software, applications, etc., for controlling and managing the process of the method. By reading and executing programs stored on a computer-readable storage medium, a computer system can effectively implement the tissue performance control method of the present disclosure.

[0091] In some embodiments, the present disclosure further provides a computer program product comprising computer-executable instructions that, when executed by a processor, cause a computer to implement the tissue performance control method described in any of the preceding items. A computer program product is a product that stores computer-executable instructions, the purpose of which is to implement the various steps and functions described in the tissue performance control method when executed by the processor 31 of a computer system. The computer-executable instructions may include an operating system, an application, embedded software, etc., to control and manage the process of the method. By using this computer program product, a user can execute the tissue performance control method of the present disclosure on a computer system.

[0092] Other embodiments of the present disclosure will readily occur to those skilled in the art after considering the specification and practicing the contents disclosed herein. The present disclosure is intended to cover any variations, uses, or adaptations of the present disclosure that follow the general principles of the present disclosure and include common knowledge or customary techniques in the art that are not disclosed in the present disclosure. The description and examples are to be considered as exemplary only, and the present disclosure is not limited to the precise structures described above and shown in the drawings, and various modifications and changes may be made without departing from the scope thereof.

Claims

1. A method for controlling the microstructure and properties of an alloy component in additive manufacturing, wherein the alloy component is manufactured by selectively melting powder layers applied layer by layer using a high-energy beam, wherein: The method comprises: Dividing one or more fused layers used to form the alloy component into performance regions according to performance requirements at different locations of the alloy component to be manufactured and determining target grain characteristics required for each performance region, wherein the target grain characteristics include at least two of single crystal structure, polycrystalline structure, polycrystalline laminar structure, oriented columnar grains, and equiaxed grains; Dividing each performance region into a grid shape consisting of a plurality of sub-regions according to the target grain characteristics and setting each performance region to have a different sub-region size; and Controlling the high-energy beam to sequentially scan the positions of the sub-regions corresponding to the powder layer according to a preset scanning path to form the one or more fused layers having different grain characteristics in each performance region; The filling scan of the high-energy beam for each sub-region is set to have the same scanning parameters; when the target grain characteristics are polycrystalline structure, polycrystalline layered structure and oriented columnar crystal, the sub-region size of the performance region corresponding to the polycrystalline structure is smaller than the sub-region size of the performance region corresponding to the polycrystalline layered structure, and the sub-region size of the performance region corresponding to the polycrystalline layered structure is smaller than the sub-region size of the performance region corresponding to the oriented columnar crystal.

2. The method according to claim 1, wherein the scanning parameters include one or more of scanning power, scanning rate, layer thickness, scanning pitch, scanning trajectory and inter-layer rotation degree. 3 . The method according to claim 1 , wherein a width of a sub-region of the polycrystalline structure corresponding to the performance region is 200 to 400 μm.

4. The method according to claim 1, further comprising: The size of the sub-region is adjusted so that the molten pools generated during the scanning process merge along the scanning pitch direction to form a molten pool similar in size and shape to the sub-region, so as to refine the grains and weaken the texture.

5. The method according to claim 1, further comprising: At least one performance region is divided into a plurality of performance gradient regions, and each performance gradient region is set to have a gradually varying sub-region size.

6. The method according to claim 5, wherein the division of the plurality of performance gradient regions comprises: The at least one performance region is divided in a cross section to achieve a gradient distribution of grain characteristics between the same layers, and / or, the at least one performance region is divided and stacked layer by layer in a longitudinal direction corresponding to multiple fusion layers to achieve a gradient distribution of grain characteristics between different layers.

7. The method according to claim 1, wherein when forming the performance region of oriented columnar crystals, the method further comprises: The incident angle of the high-energy beam is adjusted so that the growth direction of the oriented columnar crystals is consistent with the solidification direction of the molten pool.

8. An alloy component obtained by the method according to any one of claims 1 to 7.

9. A microstructure and property control device for additive manufacturing of the alloy component according to claim 8, wherein the additive manufacturing utilizes a high-energy beam to selectively melt powder layers applied layer by layer to manufacture the alloy component, wherein: The device comprises: a performance region division module configured to divide one or more fusion layers used to form the alloy component into performance regions according to performance requirements of the alloy component at different positions; a target grain characteristic determination module, configured to determine target grain characteristics required for each performance region according to the performance requirements; a sub-region division module configured to divide each performance region into a grid shape consisting of a plurality of sub-regions according to the target grain characteristics and to set each performance region to have a different sub-region size; and The scanning control module is configured to control the high-energy beam to sequentially fill and scan the positions of the sub-regions corresponding to the powder layer according to a preset scanning path to form the one or more fusion layers with different grain characteristics in each performance region.

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