Simulation and structure optimization method of nickel-based superalloy selective laser melting forming

Abstract

The application discloses a method for simulating and optimizing the structure of nickel-based high-temperature alloy selected area laser melting forming, which comprises the following steps: establishing a three-dimensional model of a part in a 3D modeling software and exporting the three-dimensional model as an STL file; adding support to the model in additive manufacturing software; importing the model into simulation software and setting relevant parameters to start running the simulation software; solving to obtain displacement deformation and stress distribution of the part generated in the laser additive manufacturing process; analyzing the solving result to perform structural optimization design on the part to avoid forming failure; and the simulation software is adopted to simulate the displacement deformation and stress distribution of the laser additive manufacturing GH3536 nickel-based high-temperature alloy part, thereby providing technical guidance for successfully forming the aerospace high-performance part by laser additive manufacturing, and being favorable to reducing the trial and error cost and improving the forming quality.

Description

Technical Field

[0001] This invention relates to the field of metal additive manufacturing, and in particular to a method for simulation and structural optimization of selective laser melting forming of nickel-based superalloys. Background Technology

[0002] Nickel-based superalloys not only possess high high-temperature strength and oxidation resistance but also excellent fatigue resistance, thus holding a pivotal position in the entire field of superalloys and being widely used in the aerospace industry. GH3536, as a typical solid solution-strengthened nickel-based superalloy, exhibits good high-temperature creep resistance below 900℃, and is therefore used in the manufacture of aero-engine combustion chambers and other components operating at high temperatures. In recent years, competition among major powers in the aerospace field has intensified, leading to increasingly higher demands for lightweight, high-strength structures, which has placed enormous pressure on traditional manufacturing industries.

[0003] Selective laser melting (SLM), as an advanced near-net-shape forming technology, can solve the problems of manufacturing complex structural parts and ultrafine grain structures that are difficult to achieve with traditional processing methods. Therefore, SLM is considered the optimal solution for manufacturing nickel-based superalloy parts. However, due to the high temperature gradient and rapid solidification characteristics of SLM, metallurgical defects such as cracks and porosity can occur during the forming process, which significantly affects the mechanical properties of the parts. Furthermore, due to the principles and processes of SLM, cracking and deformation will greatly affect the printing effect of the next layer of powder, directly leading to the failure of the forming process.

[0004] CN109439962A discloses a method for selective laser melting forming of nickel-based superalloys. This method uses powder bed selective laser melting forming technology to prepare nickel-based superalloy forming parts with high density, good internal quality, few defects, and excellent mechanical properties. However, the method uses selective laser melting technology, and metallurgical defects such as cracks and pores may occur in the nickel-based superalloy material during the forming process. This significantly affects the mechanical properties of the parts. In addition, due to the principle and process of selective laser melting technology, cracking and deformation will greatly affect the printing effect of the next layer of powder, which will directly lead to the failure of the forming process.

[0005] Therefore, this invention provides a method for simulation and structural optimization of selective laser melting forming of nickel-based high-temperature alloys, so as to reduce trial and error costs and improve the forming quality of complex parts. Summary of the Invention

[0006] The purpose of this invention is to propose a method for simulation and structural optimization of selective laser melting forming of nickel-based high-temperature alloys. This method can simulate the stress and displacement deformation of parts generated during the laser additive manufacturing process. Based on the results, the part model can be optimized to improve the compatibility of the part with additive manufacturing technology, effectively reduce trial and error costs, and improve the forming quality of the part.

[0007] The present invention adopts the following specific technical solution:

[0008] A method for simulation and structural optimization of selective laser melting forming of nickel-based superalloys, characterized in that the method includes the following steps:

[0009] S1: Use 3D modeling software to create part models according to CAD drawings, and export the models as STL format;

[0010] S2: The support for the model of the part is generated using additive manufacturing software, and the support type and support density are manually modified according to the characteristics of the part.

[0011] S3: Use simulation software to perform voxel division on the models of parts and supports;

[0012] S4: Set the support type and parameters, material configuration and required output results in the simulation software, and start running the simulation software;

[0013] S5: Based on step S4, simulation software is used to obtain the stress distribution and displacement deformation results of the forming of nickel-based superalloys by laser additive manufacturing.

[0014] Furthermore, in step S1, the tolerance of the part model is set to 0.001 mm during the format conversion process. There will inevitably be a certain deviation during the format conversion. This deviation is the maximum distance between the originally created surface or solid and the mesh that needs to be created in STL format. In order to ensure that the part is not distorted during the format conversion process, it is important to set the tolerance to 0.001 mm.

[0015] Furthermore, after the nickel-based superalloy model in S1 is established, the model's closure needs to be verified.

[0016] Furthermore, the inspection model uses an edge detection tool to check the model's closure. If it passes, there are no exposed edges; if exposed edges are shown, it is necessary to check whether the surfaces or meshes near the edges are completely joined.

[0017] Furthermore, the support types mentioned in step S2 include contour support and sheet support.

[0018] Furthermore, the support density is such that the support spacing is 1 to 2 millimeters.

[0019] Furthermore, the voxel mentioned in step S3 is a cube with a small side length, the side length of which is set to 0.25 to 0.5 mm.

[0020] Furthermore, the part model is composed of a large number of voxels.

[0021] Furthermore, in the material configuration of step S4, there is currently no option for nickel-based alloy GH3536, so IN625 alloy, which has similar performance, is selected instead for simulation.

[0022] A method for optimizing the structure of selective laser melting forming of nickel-based superalloys is disclosed. The optimization method includes redesigning the structure of the dangerous areas of the part based on the stress distribution and displacement deformation results obtained from the above-mentioned simulation method. Specifically, the optimization method involves adding or increasing the support density in areas with large overhangs of the part. In addition, the part placement angle is set to 45° to minimize the internal support of the part and fully utilize the principle that the maximum overhang angle is 45° to maximize the surface roughness of the part.

[0023] The beneficial effects of this invention are as follows:

[0024] (1) This invention utilizes simulation to analyze the stress level and deformation displacement of parts during the forming process. Based on the solution results, the model and support are structurally optimized to reduce defects generated during the forming process and improve the success rate of part printing, laying the foundation for the additive manufacturing process of complex parts.

[0025] (2) This invention can improve the success rate of forming complex parts and reduce risk and time costs to a certain extent. Through optimized structural design, it can assist industrial production and promote the large-scale commercial application of simulation software in the field of additive manufacturing. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0027] Figure 1 (a) shows the displacement deformation in an embodiment of the present invention. Figure 1 (b) shows the stress distribution in an embodiment of the present invention.

[0028] Figure 2 (a) shows the displacement deformation of Comparative Example 1 of the present invention. Figure 2(b) shows the stress distribution of Comparative Example 2 of the present invention.

[0029] Figure 3 (a) shows the displacement deformation of Comparative Example 2 of the present invention. Figure 3 (b) shows the stress distribution of Comparative Example 3 of the present invention.

[0030] Figure 4 (a) shows the displacement deformation of Comparative Example 3 of the present invention. Figure 4 (b) shows the stress distribution of Comparative Example 3 of the present invention. Detailed Implementation

[0031] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0032] Many specific details are set forth in the following description to provide a thorough understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below. Furthermore, the term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that excludes other embodiments.

[0033] Example 1

[0034] A simulation method for selective laser melting and forming of nickel-based superalloys, the method comprising the following steps:

[0035] S1: In the 3D modeling software Rhino, create a part model according to the CAD drawing. After the model is created, its closure needs to be verified before exporting it to STL format. The model closure is checked using an edge detection tool. If it passes, there are no exposed edges. If exposed edges are shown, it is necessary to check whether the surfaces or meshes near the edges are completely joined. During format conversion, in order to ensure that the part is not distorted during the format conversion process, the tolerance is set to 0.001 mm.

[0036] S2: Import the part model into the additive manufacturing software Magics to generate supports. Modify the support type and support density manually according to the part characteristics. The support types used include contour supports and sheet supports. The support density is set to a support interval of about 2 mm.

[0037] S3: Import the model of the part and support into the simulation software ANSYS Additive, perform voxel division, and set the side length of the voxels to 0.32 mm according to the memory required for calculation;

[0038] S4: Set the support type to manual input. Since the simulation software lacks data for GH3536 nickel-based superalloy, the material configuration needs to be IN625 alloy. This is because the minimum tensile strength of IN625 alloy at room temperature is 760MPa, while the strength of laser additive manufacturing GH3536 nickel-based superalloy is above 750MPa. The room temperature properties of the two alloys are similar. Set the required output results to displacement deformation and stress distribution, and start running the simulation software.

[0039] S5: Based on step S4, simulation software is used to obtain the stress distribution and displacement deformation results of the forming of nickel-based superalloys by laser additive manufacturing.

[0040] A method for optimizing the structure of a nickel-based superalloy selective laser melting forming process is disclosed. This optimization method, based on the stress distribution and displacement deformation results obtained from the aforementioned simulation method, redesigns the structure of critical areas in the part. Specifically, the optimization method involves adding or increasing the support density in areas with large overhangs. Additionally, the part is placed at a 45° angle to minimize internal supports, fully utilizing the principle that the maximum overhang angle is 45° to maximize the surface roughness of the part. The optimized structure is then incorporated into the simulation method to obtain displacement deformation and stress distribution diagrams of the part model. Figure 1 (a) and Figure 1 As shown in (b), Figure 1 (a) and Figure 1 (b) are the displacement deformation diagram and stress distribution diagram of the part model, respectively.

[0041] The beneficial effects of this invention are as follows: This invention utilizes simulation to analyze the stress level and deformation displacement of parts during the forming process, and optimizes the structure of the model and support based on the solution results, thereby reducing defects generated during the forming process and improving the success rate of part printing, laying the foundation for the additive manufacturing process of complex parts.

[0042] This invention can improve the success rate of forming complex parts and reduce risk and time costs to a certain extent. Through optimized structural design, it can assist industrial production and promote the large-scale commercial application of simulation software in the field of additive manufacturing.

[0043] Compare with Example 1

[0044] Comparative Example 1 provides a simulation method for selective laser melting and forming of nickel-based superalloys, the method comprising:

[0045] S1: In the 3D modeling software Rhino, create a part model according to the CAD drawing. After the model is created, its closure needs to be verified before exporting it to STL format. The model closure is checked using an edge detection tool. If it passes, there are no exposed edges. If exposed edges are shown, it is necessary to check whether the surfaces or meshes near the edges are completely joined. During format conversion, in order to ensure that the part is not distorted during the format conversion process, the tolerance is set to 0.001 mm.

[0046] S2: In order to explore the changes of unsupported complex parts after forming, the model of the part was imported into the additive manufacturing software Magics and sliced ​​directly without generating supports.

[0047] S3: Import the model of the part and support into the simulation software ANSYS Additive, perform voxel division, and set the side length of the voxels to 0.32 mm according to the memory required for calculation;

[0048] S4: Set the support type to manual input. Since the simulation software lacks data for GH3536 nickel-based superalloy, the material configuration needs to be selected as IN625 alloy, which has similar room temperature performance. Do not process the angle of the part model. Set the required output results to displacement deformation and stress distribution. Start running the simulation software.

[0049] S5: Based on step S4, simulation software is used to obtain the stress distribution and displacement deformation results of the laser additive manufacturing of nickel-based superalloys. The obtained displacement deformation diagram and stress distribution diagram of the part model are shown below. Figure 2 (a) and Figure 2 As shown in (b), Figure 2 (a) and Figure 2 (b) are the displacement deformation diagram and stress distribution diagram of the part model in Comparative Example 1, respectively.

[0050] Compare with Example 2

[0051] Comparative Example 2 provides a simulation method for selective laser melting and forming of nickel-based superalloys, the method comprising:

[0052] S1: In the 3D modeling software Rhino, create a part model according to the CAD drawing. After the model is created, its closure needs to be verified before exporting it to STL format. The model closure is checked using an edge detection tool. If it passes, there are no exposed edges. If exposed edges are shown, it is necessary to check whether the surfaces or meshes near the edges are completely joined. During format conversion, in order to ensure that the part is not distorted during the format conversion process, the tolerance is set to 0.001 mm.

[0053] S2: Import the part model into the additive manufacturing software Magics to generate supports. Modify the support type and support density manually according to the part characteristics. The support types used include contour supports and sheet supports. The support density is set to a support interval of about 2 mm.

[0054] S3: Import the model of the part and support into the simulation software ANSYS Additive, perform voxel division, and set the side length of the voxels to 0.32 mm according to the memory required for calculation;

[0055] S4: Set the support type to manual input. Since the simulation software lacks data for GH3536 nickel-based superalloy, the material configuration needs to be selected as IN625 alloy, which has similar room temperature performance. Do not process the angle of the part model. Set the required output results to displacement deformation and stress distribution. Start running the simulation software.

[0056] S5: Based on step S4, simulation software is used to obtain the stress distribution and displacement deformation results of the laser additive manufacturing of nickel-based superalloys. The obtained displacement deformation diagram and stress distribution diagram of the part model are shown below. Figure 3 (a) and Figure 3 As shown in (b), Figure 3 (a) and Figure 3 (b) are the displacement deformation diagram and stress distribution diagram of the part model in Comparative Example 2, respectively.

[0057] Compare with Example 3

[0058] Comparative Example 3 provides a simulation method for selective laser melting and forming of nickel-based superalloys, the method comprising:

[0059] S1: In the 3D modeling software Rhino, create a part model according to the CAD drawing. After the model is created, its closure needs to be verified before exporting it to STL format. The model closure is checked using an edge detection tool. If it passes, there are no exposed edges. If exposed edges are shown, it is necessary to check whether the surfaces or meshes near the edges are completely joined. During format conversion, in order to ensure that the part is not distorted during the format conversion process, the tolerance is set to 0.001 mm.

[0060] S2: Import the part model into the additive manufacturing software Magics for direct slicing without generating supports;

[0061] S3: Import the model of the part and support into the simulation software ANSYS Additive, perform voxel division, and set the side length of the voxels to 0.32 mm according to the memory required for calculation;

[0062] S4: Set the support type to manual input. Since the simulation software lacks data for GH3536 nickel-based superalloy, the material configuration needs to be selected as IN625 alloy, which has similar room temperature performance. Do not process the angle of the part model placement. Set the required output results to displacement deformation and stress distribution. Set the part placement angle to 45° and start running the simulation software.

[0063] S5: Based on step S4, simulation software is used to obtain the stress distribution and displacement deformation results of the laser additive manufacturing of nickel-based superalloys. The obtained displacement deformation diagram and stress distribution diagram of the part model are shown below. Figure 4 (a) and Figure 4 As shown in (b), Figure 4 (a) and Figure 4 (b) are the displacement deformation diagram and stress distribution diagram of the part model in Comparative Example 3, respectively.

[0064] By comparing Comparative Example 1 and Comparative Example 2, it can be found that the maximum deformation of the part after adding support is reduced by an order of magnitude compared with the part formed directly without support. The simulation results of the part without support show that the maximum displacement deformation of the part is more than 1 mm, which will obviously cause a serious decrease in the functionality of the part.

[0065] By comparing Comparative Example 1 and Comparative Example 3, it can be found that the area of ​​severe deformation is reduced when the part is placed at a 45° angle. This is because the part itself utilizes a self-supporting structure when the overhang angle is 45°, so no additional support is needed at the 45° overhang angle for successful forming. This indicates that the number and density of required supports can be appropriately reduced.

[0066] By comparing Example 1 and Comparative Example 1, it was found that the displacement and deformation of the part were effectively controlled after adding support and placing it at a 45° angle. It is only necessary to increase the number of supports in the dangerous area to increase the support density, which can effectively fix the suspended part of the part and prevent the part from deforming and collapsing downward.

[0067] This invention simulates the displacement deformation and stress distribution of GH3536 nickel-based superalloy parts manufactured by laser additive manufacturing. Based on the solution results, the necessary structural dimensions of the parts are optimized to adapt to the additive manufacturing industry. This provides technical guidance for the successful forming of high-performance aerospace parts by laser additive manufacturing, which helps to reduce trial and error costs and improve forming quality.

[0068] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for structure optimization of GH3536 nickel-based superalloy selective laser melting forming, characterized in that, The method comprises the following steps: S1, establishing a part model according to a CAD drawing by using a three-dimensional modeling software, and checking the model closure by using an edge detection tool, and exporting the model into an STL format; S2, importing the part model into an additive manufacturing professional software Magics to generate a support, manually modifying the support type and the support density according to the part features, wherein the support type used comprises a contour support and a sheet support, and the support density set is a support interval of 2 mm; S3, importing the part and the support model into a simulation software ANSYS Additive to perform voxel division, and setting the side length of the voxel to be 0.25-0.5 mm; S4, setting the support type and parameters, material configuration and the required output result type in the simulation software, wherein the material configuration adopts an IN625 alloy, and starting to run the simulation software; and S5, obtaining the forming stress distribution and the displacement deformation result of the laser additive manufacturing of the nickel-based superalloy by using the simulation software on the basis of step S4. In the step S1, the tolerance is set to be 0.001 mm in the format conversion process. ​ ​ ​ ​ ​ 2. The method according to claim 1, wherein, ​

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