Additive manufacturing forming method and system, storage medium and component

Abstract

The invention relates to an additive manufacturing forming method and system, a storage medium and a component. The forming method comprises the steps that a forming model corresponding to a part is obtained, the forming model comprises a solid part and a skin part, the skin part wraps the solid part, and a core-shell structure with the skin part as a shell and the solid part as a core is formed; part additive manufacturing is conducted according to the forming model, laser sintering forming is conducted on the entity part, laser area melting-solidification forming is conducted on the skin part, and a preliminary forming part is obtained; and carrying out hot isostatic pressing on the primarily formed part to obtain a compact formed part.

Description

Technical Field

[0001] This application relates to the field of additive manufacturing, and more particularly to an additive manufacturing method, system, storage medium, and component. Background Technology

[0002] Additive manufacturing (3D printing) is considered a transformative technology due to its unique manufacturing capabilities (such as high speed, design freedom, and high ability to fabricate complex and irregularly shaped components). Aerospace is a field where breakthroughs in additive manufacturing technology research and industrial applications are expected. Additive manufacturing has developed into a key technology for enhancing aerospace design and manufacturing capabilities, with applications ranging from components to complete aircraft.

[0003] Laser powder bed fusion (LPBF) is a type of laser additive manufacturing that uses a high-energy laser beam to melt metal powder layer by layer on a powder bed in a "point-line-surface" manner to obtain complex structural parts. The complete process includes part design, laser forming, post-processing, and performance testing. The forming process involves localized and drastic changes such as powder melting and rapid solidification under the action of laser processing.

[0004] However, the inventors discovered through long-term practice that due to the complete melting-solidification forming method of LPBF, this technology has a series of problems: the temperature gradient and solidification shrinkage on the formed part will generate strong stress, causing the formed part to warp and crack, increasing the forming difficulty of complex structural parts; the penetration and sintering of molten metal on the surface of the component will cause problems such as missing material and high roughness in the overhanging structure of the component; the solidification characteristics of the LPBF molten pool will make the microstructure and properties of the component have significant anisotropy, which is difficult to eliminate through subsequent heat treatment and other processes.

[0005] To address this, the main methods currently used are to avoid or mitigate the drawbacks of the LPBF melting-solidification forming method by adding and optimizing process parameters, support structures, and optimizing the shape of the formed parts.

[0006] Le et al. reduced part warping by using high laser scanning speed and low energy density (10.1016 / j.ijheatmasstransfer.2020.120284). In one prior art, several Thiessen polygons are constructed within the inner contour region to improve the shape, with random, non-adjacent scanning to reduce thermal stress concentration during the forming process. Improving the temperature distribution of the formed part can effectively reduce the need for supports; Cooper et al. achieved overhanging shape forming by adding non-contact support structures to the bottom of the overhanging structure to improve heat flow (10.3390 / inventions3010002). In another prior art, stress at locations with large areas or significant cross-sectional area changes is reduced by randomly scanning two non-intersecting U-shaped structures within the solid core region.

[0007] Adding support structures is currently the most common technical approach for LPBF (Limited-Balance Fabrication), and the vast majority of LPBF products utilize support structures for forming. By adding support structures to the formed component, deformation can be limited during forming, and overhangs can be supported, ensuring the dimensional accuracy of the component. One existing technology reduces the amount of support by adding strong and weak supports to different structures and optimizing the slice thickness of the strong and weak support structures. However, adding support structures not only increases forming time but also requires an additional support removal process in subsequent processing, further increasing costs.

[0008] Weber et al., through a systematic review of publicly available literature on unsupported additive manufacturing in industry and academia, pointed out that unsupported additive manufacturing has not yet been fully developed, and support structures remain unavoidable in LPBF technology (10.1017 / pds.2021.542). Methods for optimizing the shape of formed parts bypass difficult-to-form structures such as cantilevered and thin-walled structures, avoiding their occurrence at the design stage. Therefore, none of the existing solutions described above have solved the drawbacks of the LPBF melt-solidification forming method.

[0009] Due to the aforementioned defects and shortcomings, this application proposes an additive manufacturing method, system, storage medium, and component to overcome the deformation problem of LPBF caused by the melting-solidification process. Summary of the Invention

[0010] One object of this application is to provide an additive manufacturing method.

[0011] Another object of this application is to provide an additive manufacturing molding system.

[0012] Another object of this application is to provide a computer-readable storage medium.

[0013] Another object of this application is to provide a component.

[0014] An additive manufacturing method according to one aspect of this application includes: obtaining a molding model corresponding to a component, the molding model including a solid portion and a skin portion, the skin portion covering the solid portion to form a core-shell structure with the skin portion as the shell and the solid portion as the core; performing additive manufacturing of the component based on the molding model, wherein the solid portion is laser sintered and the skin portion is laser regional melting-solidification to obtain a preliminary molded part; and hot isostatic pressing is applied to the preliminary molded part to obtain a dense molded part.

[0015] In one or more embodiments of the additive manufacturing forming method, the step of obtaining the forming model includes dividing the solid portion into multiple solid portion partitions, including at least a first solid portion partition and a second solid portion partition. The first solid portion partition and the second solid portion partition correspond to different process parameters, with the first solid portion partition corresponding to a first process parameter and the second solid portion partition corresponding to a second process parameter.

[0016] In one or more embodiments of the additive manufacturing forming method, the step of obtaining the formed model includes: for the skin portion, the thickness is less than 2 mm; wherein, for the skin portion with an angle of less than 45° with the substrate, the thickness is less than 1 mm; the transition interface between the skin portion and the solid portion is an additive manufacturing melt flow overlap structure.

[0017] In one or more embodiments of the additive manufacturing method, the process parameters for laser sintering the solid portion include a laser power P ranging from 20 to 80 W, a laser scanning rate v ranging from 100 to 800 mm / s, a layer thickness of 20 to 40 μm, a scanning trajectory spacing of 0.07 to 0.12 mm, and a P / v ratio ranging from 0.05 to 0.25 W / (mm / s).

[0018] In one or more embodiments of the additive manufacturing method, the process parameters for laser regional melting-solidification forming of the skin portion include: laser power 280-320W, laser scanning rate 900-1100mm / s, layer thickness 20-40μm, and scanning trajectory spacing 0.07-0.12mm.

[0019] In one or more embodiments of the additive manufacturing method, the process parameters for hot isostatic pressing of the preliminary molded part include: temperature T≥1100℃, holding time t≥60min, pressure ≥140MPa, and T×t≥7.2×104min·℃.

[0020] In one or more embodiments of the additive manufacturing method, the densely formed part is further machined to obtain the target component.

[0021] In one or more embodiments of the additive manufacturing forming method, the forming model has no support structure.

[0022] In one or more embodiments of the additive manufacturing forming method, the forming model has a support structure, and the component is additively manufactured according to the forming model, wherein the solid part is laser sintered, the skin part is laser regional melting-solidification formed, and the support structure is removed to obtain the preliminary formed part.

[0023] An additive manufacturing system according to one aspect of this application includes: a memory for storing instructions executable by a processor; and a processor for executing the instructions to implement the steps of the additive manufacturing method described above, which can be implemented by a computer program.

[0024] According to one aspect of this application, a computer-readable storage medium is used to execute a program that implements the steps of the additive manufacturing method described above, which can be implemented by a computer program.

[0025] A component according to one aspect of this application is manufactured by the additive manufacturing method described above, wherein the component has a microstructure density of 99% or more corresponding to the solid portion.

[0026] The beneficial effects of the above-described embodiments include, but are not limited to: the components are metal parts, including gas turbine engine blades, impellers, shield blocks, fuel nozzles, casings, and bearing seats.

[0027] By setting a solid part and a skin part in the part, and sintering the solid part and melting the skin part, it is possible to achieve high density while having a lower stress level and a higher forming limit. Specifically, the principle is that by sintering the solid part, the internal stress of laser powder bed additive manufacturing is reduced, the deformation of complex components during the laser forming stage is alleviated, and the number of supports required in the process of laser powder bed additive manufacturing of complex components is reduced. The parts can be made without stress-relief annealing, achieving the optimization effect of reducing the processing time of subsequent processes. Furthermore, by melting and densifying the skin part to obtain a closed "core-shell" structure, the component has high density and low residual porosity after subsequent hot isostatic pressing. The grains in the main body area (core area) of the part are close to the sintered state, with uniform structure and isotropic characteristics. The mechanical properties of the formed component are no less than those of laser selective melting forming (SLM) parts prepared by conventional melting methods. In addition, by melting and densifying the skin part to obtain a closed "core-shell" structure, the surface of the formed component adopts dense skin forming parameters, ensuring that the surface of the part has low roughness. The surface quality of the parts obtained by this method is high. Attached Figure Description

[0028] The above and other features, properties and advantages of this application will become more apparent from the following description taken in conjunction with the accompanying drawings and embodiments, wherein:

[0029] Figure 1 This is a flowchart of an additive manufacturing method according to one embodiment.

[0030] Figure 2 This is a schematic diagram of the solid part and the skin part of the part to be formed according to an additive manufacturing method according to an embodiment.

[0031] Figure 3 This is a flowchart of an additive manufacturing method according to another embodiment.

[0032] Figure 4 This is a schematic block diagram of an additive manufacturing system according to an embodiment.

[0033] Figure 5 These are typical micrographs of deposited samples corresponding to the process parameters and scanning strategy of the additive manufacturing method according to the first embodiment.

[0034] Figure 6 This is a photograph of the microstructure after step S400 of the additive manufacturing method according to the first embodiment.

[0035] Figure 7 This is a schematic diagram of the external structure of a part corresponding to the additive manufacturing method according to the second embodiment.

[0036] Figure 8 This is a schematic diagram of S100 corresponding to the additive manufacturing method according to the third embodiment. Detailed Implementation

[0037] The present application will be further described below with reference to specific embodiments and accompanying drawings. More details are set forth in the following description in order to provide a full understanding of the present application. However, the present application can obviously be implemented in many other ways different from those described herein. Those skilled in the art can make similar extensions and derivations based on actual application situations without departing from the spirit of the present application. Therefore, the scope of protection of the present application should not be limited by the content of this specific embodiment.

[0038] Furthermore, this application uses specific terms to describe embodiments of the application, such as "an embodiment," "one embodiment," and / or "some embodiments," which refer to a particular feature, structure, or characteristic related to at least one embodiment of the application. Therefore, it should be emphasized and noted that "an embodiment" or "one embodiment" mentioned twice or more in different locations in this specification do not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of the application can be appropriately combined.

[0039] Flowcharts are used in this application to illustrate the operations performed by the system according to embodiments of this application. It should be understood that the preceding or following operations are not necessarily performed in exact order. Other operations may be added to these processes, or one or more operations may be removed from these processes.

[0040] In this application, liquid phase sintering refers to a sintering process in which a liquid phase is generated. For liquid phase sintering of a single alloy material, the sintering temperature is between the liquidus line and the solidus line. Solid phase sintering refers to the process in which powder forms a continuous solid structure through inter-element diffusion at high temperatures. No liquid phase is formed during the sintering process. For solid phase sintering of a single alloy material, the sintering temperature is below the liquidus line.

[0041] This invention provides a laser additive manufacturing method for complex alloy components, solving the problem of deformation easily occurring in complex component structures during laser additive manufacturing. This invention can be used to form various metal parts, such as gas turbine engine blades, impellers, shield blocks, fuel nozzles, casings, bearing housings, etc.

[0042] refer to Figure 1 Laser deposition forming methods may include:

[0043] S100: Obtain the molding model 200 corresponding to part 100. The schematic structure can be referenced. Figure 2As shown, the molded model 200 includes a solid part 1 and a skin part 2, wherein the skin part 2 covers the solid part 1, forming a core-shell structure with the skin part 2 as the shell and the solid part 1 as the core.

[0044] The process of obtaining the forming model 200 involves a hot isostatic pressing (HIP) step, described later, which causes dimensional shrinkage, especially after HIP. Therefore, dimensional pre-correction is performed on the initial part model. This step ensures that the corrected part model, after subsequent processing but before machining, achieves final part dimensions that meet the requirements of the engineering blank and closely approximate the part's design dimensions. Furthermore, as is well known to those skilled in the art, the optimization of the forming model 200 essentially involves mapping the model's features before and after deformation. This mapping model can be an empirical model, an experimental model, a model based on physical principles, or a data-driven model. That is, the model dimensional optimization methods include, but are not limited to, simulation methods such as the finite element method, artificial intelligence methods such as machine learning and neural networks, empirical formulas, and theoretical derivations.

[0045] S200: The component 100 is obtained by additive manufacturing according to the molding model 200, wherein the solid part 1 is laser sintered and the skin part 2 is laser regional melting-solidification to obtain a preliminary molded part.

[0046] Specifically, specific process parameter experiments can be conducted before additive manufacturing to obtain the optimal process parameters. For the skin portion 2, a higher power density is used to achieve melting-solidification forming in this region and obtain a relatively dense structure. Common additively manufactured materials such as nickel-based superalloys can all exist in the process range of relatively dense material structure. The solid portion 1 is formed by laser sintering to achieve solid-phase sintering and liquid-phase sintering under laser energy input. The temperature during the forming process is controlled below the melting point of the forming material, ultimately achieving low-stress forming of the internal solid region. In some embodiments, the step of obtaining the forming model 200 includes dividing the solid portion 1 into multiple solid portion partitions 11, including at least a first solid portion partition 111 and a second solid portion partition 112, but not limited thereto. For example, reference can be made to... Figure 8As shown, there can be four solid partitions: a first solid partition 111, a second solid partition 112, a third solid partition 113, and a fourth solid partition 114. Furthermore, the process parameters corresponding to the first solid partition 111 and the second solid partition 112 are different; the first solid partition 111 corresponds to the first process parameter, and the second solid partition 112 corresponds to the second process parameter. The internal solid region can be further divided into multiple regions prepared using different processes. The size, process, and microstructure density of different process regions are determined according to the specific needs of the part design process engineers. For details, please refer to the content of the third embodiment described later.

[0047] In some embodiments, the step of obtaining the molded model 200 includes: for the skin portion 2, the thickness is less than 2 mm; wherein, for the skin portion 2 with an angle of less than 45° to the substrate, the thickness is less than 1 mm; the transition interface between the skin portion 2 and the solid portion 1 is an additive manufacturing melt-over structure. Additionally, in some embodiments, for the surface shell structure with an angle of not less than 45° to the substrate, the thickness should not exceed 1.5 mm.

[0048] In some embodiments, the process parameters for laser sintering the solid portion 1 include a laser power P ranging from 20-80W, a laser scanning rate v ranging from 100-800mm / s, a layer thickness of 20-40μm, a scanning trajectory spacing of 0.07-0.12mm, and a P / v ratio ranging from 0.05-0.25W / (mm / s). Using the process parameters and skin structure described in the above embodiments, the microstructure of this region can be made dense and crack-free, and the skin portion 2 does not have any through-holes connecting the solid portion 1 to the atmosphere.

[0049] In some embodiments, the process parameters for laser regional melting-solidification forming of the skin portion 2 include: laser power 280-320W, laser scanning rate 900-1100mm / s, layer thickness 20-40μm, and scanning trajectory spacing 0.07-0.12mm. In some embodiments, for nickel-based superalloys, the process parameter combination is: laser power P ranging from 20-80W, laser scanning rate v ranging from 100-800mm / s, layer thickness 40μm, scanning trajectory spacing 0.10mm, and the P / v ratio ranging from 0.10-0.16W / (mm / s).

[0050] In the additive manufacturing process, the established molding model 200 is sliced, and specific process parameters such as laser and scanning paths are input as described above, and converted into corresponding control programs for input to the equipment. Additionally, the equipment prepares the powder and uses inert gas to protect the molding process from oxidation. The laser selective melting equipment moves along a predetermined path, melting layer by layer until the desired part shape is formed. After the molding process is complete, the part is allowed to cool and then removed from the deposited state. Post-molding heat treatment is then performed as needed.

[0051] S300: Hot isostatic pressing is applied to the preliminary formed part to obtain a dense formed part.

[0052] The preliminary formed part can be removed from the substrate by means of wire cutting, etc.; hot isostatic pressing is performed to make the internal solid part 1 dense; in some embodiments, the hot isostatic pressing process should be within the following range: temperature T≥1100℃, holding time t≥60min, pressure≥140MPa, and T×t≥7.2×104min·℃.

[0053] After S300, the resulting component 100 can have a microstructure density of 99% or higher corresponding to the solid part 1.

[0054] As described above, the process described above can achieve a molded model 200 without a support structure, thereby simplifying the structure and saving manufacturing costs. However, if the molded model 200 has a support structure, the component 100 is obtained through additive manufacturing based on the molded model 200. In this process, the solid part 1 is laser sintered, the skin part 2 is laser-melted and solidified, and the support structure is removed to obtain the preliminary molded part, followed by a hot isostatic pressing step.

[0055] refer to Figure 3 As shown, the manufacturing method may further include a post-processing step S400, namely, machining the densely formed part to obtain the target component 100. For example, according to the actual additional requirements of the part, selective operations such as microstructure control, dimensional machining, and surface treatment can be carried out on specific materials and parts. The scope of the microstructure control post-processing includes, but is not limited to, heat treatment, shot blasting, etc., to ultimately obtain a microstructure that meets performance requirements; the scope of the dimensional machining and surface treatment post-processing includes, but is not limited to, grinding, external force straightening, turning, milling, planing, and external surface machining methods such as shot peening, to ultimately meet the requirements of the part design.

[0056] The additive manufacturing method described in the above embodiments divides the forming of complex components into an internal solid part called the "core" and an external skin part called the "shell". The solid part is formed by laser sintering to achieve solid-state sintering and liquid-state sintering, resulting in a highly dense solid. The skin part is formed by melting-solidification to obtain a dense skin. Thus, a complex component composed of a sintered internal solid part called the "core" and a dense skin part called the "shell" is obtained. Then, the formed component is subjected to hot isostatic pressing to achieve densification of the sintered solid part, and finally a completely dense sample is obtained.

[0057] The methods described in the above embodiments cleverly combine laser melting-solidification forming and laser sintering, thus minimizing the deformation problems caused by the melting-solidification method of LPBF. Laser sintering (LS) uses a laser as a heat source to sinter powder particles through solid-state or liquid-state sintering to form components, which differs from the completely melting-solidification forming method of LPBF. While LS can manufacture complex structural parts, the lower laser energy input (i.e., the metal powder is not completely melted, only sintered) results in significantly lower thermal stress during the forming process compared to LPBF. However, the rapid laser movement in LS leads to a short sintering process, resulting in LS components having numerous interconnected pores that are difficult to completely eliminate in subsequent processing steps. LS products suffer from low density, porous surfaces, and high roughness. By bonding powders with binders and subsequently debinding and sintering, or by solder infiltration, such as binder jetting, the effects of avoiding thermal stress deformation and achieving supportless forming can also be achieved. However, this method requires an additional binder removal process, often facing problems such as residual binder element impurities, sintering dimensional shrinkage, and deformation. Therefore, although LS (Laminated Structural Bonding) can achieve a low-stress state and realize supportless structure forming, it faces problems of high porosity and high surface roughness due to insufficient heat input and a large number of interconnected pores, making it difficult to achieve industrial application.

[0058] Regarding the scheme described in the above embodiments, by sintering the solid part, the temperature of the laser-heated area is much lower than that of conventional melting-solidification forming methods. This reduces the internal stress in laser powder bed additive manufacturing and alleviates the deformation of complex components during the laser forming stage. By melting and densifying the skin portion to obtain a closed "core-shell" skin-internal structure, the component achieves high density and low residual porosity after subsequent hot isostatic pressing. The grains in the main body region (core region) are close to the sintered state, exhibiting uniform microstructure and isotropic characteristics. The mechanical properties of the formed component are no less than those of additively manufactured components prepared by conventional melting methods. By melting and densifying the skin portion to obtain a closed "core-shell" structure, the surface of the formed component employs dense skin forming parameters, ensuring low surface roughness and resulting in high surface quality of the parts produced by this method. Compared with the laser additive manufacturing melting process, the embodiment uses laser sintering forming in the solid part, which has a lower stress level and a higher forming limit. Compared with conventional laser sintering, the embodiment's solution designs a dense thin skin on the surface of the part, which achieves higher density after hot isostatic pressing. Compared with binder spraying additive manufacturing, the embodiment's solution does not require debinding and sintering, avoiding residues and uncontrollable dimensional deformation.

[0059] To more clearly and specifically illustrate the content described in the above embodiments, the following describes the additive manufacturing method through specific structures and parameters.

[0060] First Embodiment

[0061] In this embodiment, the component is a cube. To obtain the optimal process parameters, eight 15mm×15mm×15mm cubes are prepared. The preparation steps are as follows:

[0062] Step 1: The model size was corrected using empirical parameters of linear shrinkage during sintering. All sample sizes were enlarged by 20% proportionally, and a block model was designed based on UG NX CAD software. In this model design, the shell thickness was 1.5mm for all samples. The obtained model was sliced ​​and its positions were arranged using Magics software.

[0063] Step two: Set the model process parameters and scanning strategy. A strip scanning strategy is adopted. For the skin region, the microstructure must be dense and crack-free, and there must be no pores connecting the internal solid region to the atmosphere.

[0064] Through testing multiple samples, the following process combinations were obtained for the 1.5mm thick epidermal region in this embodiment: Sample 1: laser power 300W, laser scanning rate 1000mm / s, layer thickness 40μm, scanning trajectory spacing 0.10mm; Sample 2: laser power 280W, laser scanning rate 900mm / s, layer thickness 40μm, scanning trajectory spacing 0.07mm; Samples 3-6: laser power 320W, laser scanning rate 1100mm / s, layer thickness 40μm, scanning trajectory spacing 0.12mm; Samples 7 and 8: laser power 280W, laser scanning rate 900mm / s, layer thickness 20μm, scanning trajectory spacing 0.12mm. For the internal solid portion, the density of the internal solid tissue must be no less than 60% and no more than 90%. The process combinations for the internal solid portions of each sample in this embodiment are shown in Table 1. The shell region was fabricated using a laser with a power of 180W, a scanning speed of 350mm / s, and a layer thickness of 20μm. The fabrication processes for the internal solid regions of each sample are shown in Table 1.

[0065] Table 1. Process of the internal solid region in the first embodiment.

[0066]

[0067] The preparation results show that the density of the internal solid tissue of samples 1-8 is between 60% and 90%. The surface area of ​​the samples is a dense melt-solidification structure, while the internal solid area has a sintered structure. Typical microstructure photographs of the deposited samples are shown below. Figure 5 As shown.

[0068] Step 3, additive manufacturing. An EOS M280 laser was used for fabrication, and an IPG 400 fiber-coupled laser was employed. The pre-processed slice model file from Step 1 was input with specific laser and scanning path process parameters based on the constraints of Step 2, and these parameters were converted into the corresponding control program and input into the equipment. The powder was loaded after undergoing a 1-hour high-temperature vacuum drying treatment at 120°C. An inert gas was used to protect the forming process from oxidation. The forming program was executed. After the forming program was completed, the part was allowed to cool and then removed from the deposited state. The support structure was then removed.

[0069] Step 4, Hot Isostatic Pressing (HIP). The samples are removed from the substrate using methods such as wire cutting and then subjected to HIP. For samples 1-3, the HIP process is an isothermal temperature of 1100℃, an isothermal time of 66 min, and a pressure of 140 MPa; for samples 4-6, the HIP process is a temperature T ≥ 1200℃, a holding time of 60 min, and a pressure of 140 MPa. After this step, the surface area of ​​the HIP samples exhibits a dense melt-solidification structure with obvious columnar crystals, while the internal solid area has a dense structure with a density exceeding 99%, consisting of fine, uniform equiaxed grains. Typical microstructure photographs of the HIP samples are shown below. Figure 6 As shown.

[0070] Second Embodiment

[0071] In this embodiment, three mechanical property test specimens were prepared, and the steps are as follows:

[0072] Step 1: Design a block model using UG NX CAD software, such as... Figure 7 As shown; the model size was corrected using empirical parameters of linear shrinkage during sintering, with the tensile direction magnified by 1.2 times and the perpendicular tensile direction magnified by 1.3 times; in this model scheme, the shell thickness is 1mm for all parts.

[0073] Step 2: The laser power for the shell area is 290W, the laser scanning rate is 1000mm / s, the layer thickness is 40μm, and the scanning trajectory spacing is 0.1mm; the laser power for the internal solid area is 60W, the laser scanning rate is 500mm / s, the layer thickness is 40μm, and the scanning trajectory spacing is 0.1mm.

[0074] Step 3, additive manufacturing. An EOS M280 laser was used for fabrication, and an IPG 400 fiber-coupled laser was employed. The pre-processed slice model file from Step 1 was input with specific laser and scanning path process parameters based on the constraints of Step 2, and these parameters were converted into the corresponding control program and input into the equipment. The powder was loaded after undergoing a 1-hour high-temperature vacuum drying treatment at 120°C. An inert gas was used to protect the forming process from oxidation. The forming program was then executed. After the forming program was completed, the part was allowed to cool and then removed from the deposited state.

[0075] Step 4, hot isostatic pressing. The hot isostatic pressing process is carried out at a temperature of 1200℃, a holding time of 120min, and a pressure of 140MPa.

[0076] Step 5, post-processing. Following the sample mechanical property testing standards, the sample was machined using a milling machine to remove the outer skin area, resulting in a mechanical property test piece consisting entirely of fine, equiaxed internal structures.

[0077] The quasi-static room temperature tensile mechanical properties of the parts obtained through the above steps are shown in Table 2.

[0078] This embodiment provides a conventional laser powder bed melting-solidification forming sample as a comparative sample (except for the additive manufacturing forming process and forming strategy, other processing procedures of this comparative sample are the same as the processing steps provided by the present invention). The additive manufacturing forming process adopted is a laser power of 290 W, a laser scanning rate of 1000 mm / s, a layer thickness of 40 μm, a scanning track spacing of 0.1 mm, and it undergoes the same hot isostatic pressing process as in Step 4. Through comparison, it can be seen that the parts prepared by the additive manufacturing forming method introduced in the above embodiments have higher quasi-static room temperature tensile strength.

[0079] Table 2 Mechanical properties of the second embodiment and the comparative sample

[0080]

[0081] Third Embodiment

[0082] This embodiment further divides the internal area in terms of process, aiming to illustrate the flexibility of the forming strategy of the present invention.

[0083] Step 1: Design a 15 mm × 15 mm × 15 mm cube model based on UG NX CAD software. The thickness of the shell is all 1 mm; as Figure 8 shown, the internal solid part 1 is further evenly divided into four areas, forming a "field" shape.

[0084] Step 2: For the shell area, the process laser power is 290 W, the laser scanning rate is 1000 mm / s, the layer thickness is 40 μm, and the scanning track spacing is 0.1 mm; for the internal solid area, the process for the first solid part partition 111 is a laser power of 60 W, a laser scanning rate of 500 mm / s, a layer thickness of 40 μm, and a scanning track spacing of 0.1 mm, the process for the second solid part partition 112 is a laser power of 40 W, a laser scanning rate of 300 mm / s, a layer thickness of 40 μm, and a scanning track spacing of 0.1 mm; the process for the third solid part partition 113 is a laser power of 40 W, a laser scanning rate of 400 mm / s, a layer thickness of 40 μm, and a scanning track spacing of 0.1 mm; the process for the fourth solid part partition 114 is a laser power of 70 W, a laser scanning rate of 600 mm / s, a layer thickness of 40 μm, and a scanning track spacing of 0.1 mm.

[0085] Step 3, additive manufacturing. An EOS M280 laser was used for fabrication, and an IPG 400 fiber-coupled laser was employed. The pre-processed slice model file from Step 1 was input with specific laser and scanning path process parameters based on the constraints of Step 2, and these parameters were converted into the corresponding control program and input into the equipment. The powder was loaded after undergoing a 1-hour high-temperature vacuum drying treatment at 120°C. An inert gas was used to protect the forming process from oxidation. The forming program was then executed. After the forming program was completed, the part was allowed to cool and then removed from the deposited state.

[0086] Step 4, hot isostatic pressing. The hot isostatic pressing process is carried out at a temperature of 1200℃, a holding time of 120min, and a pressure of 140MPa.

[0087] Through the above steps, the resulting part has a microstructure density of over 99%, and the grain morphology and size are different.

[0088] refer to Figure 4 As shown, another aspect of this application provides an additive manufacturing forming system, including a memory 1001 for storing instructions executable by a processor; and a processor 1002 for executing the instructions to implement the steps of the additive manufacturing forming method described in the above embodiments, which can be implemented by a computer program.

[0089] It should be noted that the memory 1001 and processor 1002 described above are not limited to a specific memory or processor. In some cases, the memory 1001 and processor 1002 can have a distributed structure. For example, they can include a memory and processor located at the additive manufacturing field and a back-end cloud respectively, with the additive manufacturing field and the back-end cloud jointly implementing the additive manufacturing forming method described above. Furthermore, in embodiments employing a distributed structure, the specific execution terminal for each step can be adjusted according to actual conditions, and the specific implementation scheme of each step on a particular terminal should not limit the scope of protection of this application.

[0090] Another aspect of this application provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the additive manufacturing method described in the above embodiments that can be implemented by the computer program. For details, please refer to the description above, which will not be repeated here.

[0091] In addition, it is understood that the aforementioned computer-readable storage medium may also be in the form of a system, that is, including multiple computer-readable storage sub-media, so that the steps of the additive manufacturing method described above can be implemented by a computer program through multiple computer-readable storage media.

[0092] It is understood that another aspect of this application also provides a component 100 manufactured by the additive manufacturing method described in the above embodiments, wherein the component has a microstructure density of 99% or higher corresponding to the solid portion 1. For a gas turbine engine, the component is a metal part, such as a nickel-based superalloy part, and the component may include gas turbine engine blades, impellers, shield blocks, fuel nozzles, casings, bearing seats, etc.

[0093] In summary, the beneficial effects of the additive manufacturing methods, systems, storage media, and components described in the above embodiments include, but are not limited to, setting a solid part and a skin part on the part entity, sintering the solid part and melting the skin part, achieving high density while having a lower stress level, and achieving a higher forming limit. Specifically, the principle is that by sintering the solid part, the internal stress of laser powder bed additive manufacturing is reduced, the deformation of complex components during the laser forming stage is alleviated, and the number of supports required in the process of laser powder bed additive manufacturing of complex components is reduced. The parts can be made without stress-relief annealing, achieving the optimization effect of reducing the processing time of subsequent processes. Furthermore, by melting and densifying the skin part to obtain a closed "core-shell" structure, the component has high density and low residual porosity after subsequent hot isostatic pressing. The grains in the main body area (core area) of the part are close to the sintered state, with uniform structure and isotropic characteristics. The mechanical properties of the formed component are no less than those of laser selective melting forming (SLM) parts prepared by conventional melting methods. In addition, by melting and densifying the skin part to obtain a closed "core-shell" structure, the surface of the formed component adopts dense skin forming parameters, ensuring that the surface of the part has low roughness. The surface quality of the parts obtained by this method is high.

[0094] It is understood that the system in the preceding embodiments may include one or more hardware processors 1002, such as a system-on-a-chip (SOC), microcontroller, microprocessor (e.g., MCU chip or 51 microcontroller), reduced instruction set computer (RISC), application-specific integrated circuit (ASIC), application-specific instruction integrated processor (ASIP), central processing unit (CPU), graphics processing unit (GPU), physical processing unit (PPU), microcontroller unit, digital signal processor (DSP), field-programmable gate array (FPGA), advanced RISC machine (ARM), programmable logic device (PLD), any circuit or processor capable of performing one or more functions, etc.

[0095] The steps of the methods described in conjunction with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of both. The software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to a processor such that the processor can read and write information to / from the storage medium. In an alternative, the storage medium may be integrated into the processor. The processor and storage medium may reside in an ASIC. The ASIC may reside in a user terminal. In an alternative, the processor and storage medium may reside as discrete components in the user terminal.

[0096] In one or more exemplary embodiments, the described functionality may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software as a computer program product, the functionality may be stored or transmitted as one or more instructions or code on or via a computer-readable medium. A computer-readable medium includes both computer storage media and communication media, encompassing any medium that facilitates the transfer of a computer program from one location to another. A storage medium may be any available medium accessible to a computer. By way of example and not limitation, such a computer-readable medium may include RAM, ROM, EEPROM, CD-ROM or other optical disc storage, disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and is accessible to a computer. Any connection is also legitimately referred to as a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of a medium. As used in this article, disk and disc include compact discs (CDs), laser discs, optical discs, digital multi-purpose discs (DVDs), floppy disks, and Blu-ray discs. Disks typically reproduce data magnetically, while discs reproduce data optically using lasers. Combinations of these should also be included within the scope of computer-readable media.

[0097] While this application discloses preferred embodiments as described above, it is not intended to limit the scope of this application. Any changes and modifications can be made by those skilled in the art without departing from the spirit and scope of this application. Therefore, any modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of this application without departing from the content of the technical solution of this application shall fall within the protection scope defined by the claims of this application.

Claims

1. An additive manufacturing forming method characterized by, The method comprises the following steps: obtaining a forming model (200) corresponding to a component (100), the forming model (200) comprising a solid part (1) and a skin part (2), the skin part (2) covering the solid part (1) to form a core-shell structure with the skin part (2) as the shell and the solid part (1) as the core; obtaining the component (100) by additive manufacturing according to the forming model (200), wherein the solid part (1) is formed by laser sintering, and the skin part (2) is formed by laser zone melting-solidification to obtain a preliminary formed part; performing hot isostatic pressing on the preliminary formed part to obtain a dense formed part.

2. The additive manufacturing forming method of claim 1, wherein, The step of obtaining the forming model (200) comprises partitioning the solid part (1), and the solid part (1) of the forming model (200) comprises a plurality of solid part partitions (11), at least comprising a first solid part partition (111) and a second solid part partition (112), the first solid part partition (111) and the second solid part partition (112) corresponding to different process parameters, the first solid part partition (111) corresponding to a first process parameter, and the second solid part partition (112) corresponding to a second process parameter.

3. The additive manufacturing forming method of claim 1, wherein, The step of obtaining the forming model (200) comprises that the thickness of the skin part (2) is less than or equal to 2 mm, and the thickness of the skin part (2) with an included angle less than 45° with the substrate is less than or equal to 1 mm; and the transition interface between the skin part (2) and the solid part (1) is an additive manufacturing melt channel lap joint structure.

4. The additive manufacturing forming method of claim 1, wherein, The process parameters for laser sintering of the solid part (1) comprise that the laser power P ranges from 20 W to 80 W, the laser scanning speed v ranges from 100 mm / s to 800 mm / s, the layer thickness is 20 μm to 40 μm, the scanning track spacing is 0.07 mm to 0.12 mm, and the ratio of P / v ranges from 0.05 W / (mm / s) to 0.25 W / (mm / s).

5. The additive manufacturing forming method of claim 1, wherein, The process parameters for laser zone melting-solidification forming of the skin part (2) comprise that the laser power is 280 W to 320 W, the laser scanning speed is 900 mm / s to 1100 mm / s, the layer thickness is 20 μm to 40 μm, and the scanning track spacing is 0.07 mm to 0.12 mm.

6. The additive manufacturing forming method of claim 1, wherein, The process parameters for hot isostatic pressing of the preliminary formed part comprise that the temperature T is greater than or equal to 1100°C, the holding time t is greater than or equal to 60 min, the pressure is greater than or equal to 140 MPa, and T×t is greater than or equal to 7.2×104 min·℃.

7. The additive manufacturing forming method of claim 1, wherein, The method further comprises machining the dense formed part to obtain a target component (100).

8. The additive manufacturing forming method of claim 1, wherein, The forming model (200) has no support structure.

9. The additive manufacturing forming method of claim 1, wherein, The forming model (200) has a support structure, and the component (100) is obtained by additive manufacturing according to the forming model (200), wherein the solid part (1) is formed by laser sintering, the skin part (2) is formed by laser zone melting-solidification, and the support structure is removed to obtain the preliminary formed part.

10. An additive manufacturing forming system (1000), characterized by, The method comprises the following steps: a memory (1001) for storing instructions executable by a processor; Processor (1002) for executing the instructions to implement the steps of the additive manufacturing method according to any one of claims 1-9 that can be implemented by a computer program.

11. A computer readable storage medium having a computer program thereon, characterized in that, The program is executed by the processor to implement the steps of the additive manufacturing method according to any one of claims 1-9 that can be implemented by a computer program.

12. A component (100) characterized by The component is a metal piece, including a gas turbine engine blade, a vane, a shroud block, a fuel nozzle, a casing, a bearing seat.

13. The component (100) of claim 12, characterized in that The component is a metal piece, including a gas turbine engine blade, a vane, a shroud block, a fuel nozzle, a casing, a bearing seat.

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