A method for eliminating cracks in heterogeneous alloys based on bionic structure

Abstract

The present invention discloses a method for eliminating cracks in heterogeneous alloys based on a bionic structure, which relates to the technical field of additive manufacturing and comprises the following steps: step 1: obtaining the material type and density distribution information of the heterogeneous alloy at the crack, and adopting a bionic heterogeneous structure with corresponding parameters; step 2: obtaining the crack size, generating a three-dimensional model of the bionic heterogeneous structure for eliminating the crack in combination with the bionic heterogeneous structure parameters, performing printing preprocessing, and generating layered contour data and a deposition working path; step 3: according to the generated layered contour data and deposition working path, delivering the corresponding metal material in real time, performing directed energy deposition forming layer by layer, and repairing the original crack to a complete surface with a bionic heterogeneous structure; after eliminating the crack using this method, the crack can be effectively suppressed from continuing to extend in other directions, and at the same time, the surface strength of the material can be enhanced to a certain extent, which can effectively solve the cracking problem of heterogeneous alloys manufactured by laser cladding.

Description

Technical Field

[0001] The present application relates to the field of additive manufacturing technology, and in particular to a method for eliminating cracks in heterogeneous alloys based on a bionic structure. Background Art

[0002] Directed energy deposition (DED) (laser cladding) is a laser additive manufacturing process in which a feedstock in the form of powder or wire is fed onto a substrate simultaneously focused with an energy source such as a laser beam, electron beam, or plasma arc. This creates a small molten pool, upon which material is deposited layer by layer. Heterogeneous alloys, composed of two or more dissimilar metals, possess unique physical and chemical properties not found in conventional alloys. The performance of these alloys depends on their metallic composition and unique internal structure. These unique structures are difficult to achieve using traditional manufacturing methods. However, DED, due to its molten pool-forming manufacturing principle, is highly applicable for the repair and fabrication of heterogeneous alloys. Numerous studies have demonstrated the use of DED to create uniform and precise heterogeneous alloy structures, significantly improving the performance of these materials. Metal materials manufactured and remanufactured using laser cladding can be reinforced with superior properties such as increased strength and ductility, offering significant potential for application across various industrial sectors.

[0003] In practical engineering applications, cracking is a common problem in the manufacture of heterogeneous alloys and in welded joints. In particular, the liquefaction cracking, solidification cracking, and solid-state cracking that occur during the manufacturing process of space heterogeneous alloys severely impact their application. Therefore, preventing and eliminating these cracks is a key research focus. In recent years, with the advancement of research on biomimetic heterostructures, heterogeneous alloy crack elimination technologies that mimic biological heterostructures have shown promise in effectively repairing cracks. Summary of the Invention

[0004] In order to solve the above technical problems, the present application provides a method for eliminating cracks in heterogeneous alloys based on a bionic structure. The present invention constructs a bionic heterogeneous structure at the crack through a laser cladding manufacturing method, which can effectively eliminate the cracks in the heterogeneous alloy. After repair, the structure has good stability and can better solve the above problems.

[0005] A method for eliminating cracks in heterogeneous alloys based on a bionic structure comprises the following steps:

[0006] Step 1: Obtain the material type and density distribution information of the heterogeneous alloy at the crack, and adopt a bionic heterostructure with corresponding parameters;

[0007] Step 2: Obtain the crack size, combine the bionic heterostructure parameters to generate a three-dimensional model of the bionic heterostructure for eliminating the crack, and perform printing preprocessing to generate layered contour data and deposition work path;

[0008] Step 3: Based on the generated layered profile data and deposition work path, the corresponding metal material is delivered in real time, and directed energy deposition is performed layer by layer to repair the original cracks into an intact surface with a bionic heterogeneous structure;

[0009] Step 4: After cooling, perform crack inspection on the crack-eliminated surface to ensure the crack elimination effect. If cracks still exist, repeat steps 1 to 3.

[0010] Preferably, the density distribution information of the heterogeneous alloy in step 1 includes the distribution direction and distribution density of the heterogeneous alloy.

[0011] Preferably, the crack size in step 2 includes crack length and crack depth.

[0012] Preferably, the bionic heterostructure used in step 2 is a bionic orientation gradient structure.

[0013] Preferably, in step 3, during the directed energy deposition process, the printing process parameters are:

[0014] The laser spot diameter is 1-3mm, the laser power is 400-600W, the print head scanning speed is 200-400mm / min, the powder feeding rate of the powder feeding bin is 10-30g / min, the protective gas flow rate is 8-12L / min, and the powder carrier gas flow rate is 8-13L / min.

[0015] Preferably, during the directed energy deposition process, the printing direction of the bionic orientation gradient structure of the crack bottom layer and the crack top layer is perpendicular to the crack extension direction.

[0016] Beneficial effects of the present invention:

[0017] The present invention can effectively control the bonding strength and density between multiple metals, providing more convenience for the design of heterogeneous alloys;

[0018] By using the laser cladding manufacturing method, a bionic heterogeneous structure is constructed at the crack, which can effectively eliminate the cracks in the heterogeneous alloy and provide good stability after repair;

[0019] After eliminating cracks using this method, it can effectively inhibit the cracks from continuing to extend in other directions. At the same time, it can enhance the surface strength of the material to a certain extent. It can better solve the cracking problem of heterogeneous alloys manufactured by laser cladding and help promote the application of heterogeneous alloy materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the bionic orientation gradient structure of the present invention;

[0021] Figure 2Schematic diagram of crack elimination of the bionic orientation gradient structure with a material density distribution of 1:1 according to the present invention;

[0022] Figure 3 Schematic diagram of crack elimination of the bionic orientation gradient structure with a material density distribution of 2:1 according to the present invention;

[0023] Figure 4 Schematic diagram of crack elimination of the bionic orientation gradient structure with a material density distribution of 3:1 according to the present invention. DETAILED DESCRIPTION

[0024] In order to make the purpose, processing design scheme and advantages of the embodiments of this application clearer, the design scheme and manufacturing method in the embodiments of this application will be clearly and completely described below in conjunction with the embodiment drawings in this application.

[0025] A method for eliminating cracks in heterogeneous alloys based on a bionic structure comprises the following steps:

[0026] Step 1: Obtain the material type and density distribution information of the heterogeneous alloy at the crack, and adopt a bionic heterostructure with corresponding parameters;

[0027] Step 2: Obtain the crack size, combine the bionic heterostructure parameters to generate a bionic heterostructure 3D model for eliminating the crack, and perform printing preprocessing, i.e., slicing, to generate layered contour data and deposition work path;

[0028] Step 3: According to the generated layered profile data and deposition work path, the corresponding metal material is delivered in real time, and directed energy deposition is performed layer by layer. During the directed energy deposition process, the printing process parameters are:

[0029] Laser spot diameter 1-3mm, laser power 400-600W, print head scanning speed 200-400mm / min, powder feeding rate 10-30g / min, shielding gas flow rate 8-12L / min, powder carrier gas flow rate 8-13L / min;

[0030] Repair the original cracks into a complete surface with a bionic heterogeneous structure;

[0031] Step 4: After cooling, perform crack inspection on the crack-eliminated surface to ensure the crack elimination effect. If cracks still exist, repeat steps 1 to 3.

[0032] Furthermore, the crack size in step 2 includes crack length and crack depth.

[0033] Furthermore, the bionic heterostructure used in step 2 is a bionic orientation gradient structure.

[0034] Preferably, during the directed energy deposition process, the printing direction of the bionic orientation gradient structure of the crack bottom layer and the crack top layer is perpendicular to the crack extension direction.

[0035] like Figure 1 As shown, the bionic heterogeneous structure provided by the present application is inspired by the gradient structure of the mantis shrimp's forelimbs, which has extremely strong hardness and impact resistance. It adopts a bionic orientation gradient and forms a bionic orientation gradient structure with a spiral periodic arrangement. Different alloy materials are used between each gradient according to the material density distribution, thereby suppressing the generation of cracks in all directions, enhancing the impact resistance of the material surface, and further reducing the possibility of cracks.

[0036] In order to facilitate the understanding of the present invention, the following examples are given:

[0037] The materials of the bionic orientation gradient structure are metal material A and metal material B;

[0038] Metal material A and metal material B are two metal materials of cracking heterogeneous alloy materials;

[0039] Metal material A and metal material B are deposited on each other to generate a bionic orientation gradient structure;

[0040] Among them, the bionic orientation gradient structure includes ABA bionic orientation gradient structure, AAB bionic orientation gradient structure, and AAAB bionic orientation gradient structure.

[0041] For heterogeneous alloy materials with different distribution densities, different bionic orientation gradient structure parameters are used;

[0042] Figure 2 Example 1 of the present invention is shown, in which metal material A and metal material B are deposited in sequence, the number of deposited layers is 13, and the ratio of metal material A to metal material B is 1:1, that is, ABAB.

[0043] Figure 3 Example 2 of the present invention is shown, in which metal material A and metal material B are deposited in sequence, the number of deposited layers is 13, and the ratio of metal material A to metal material B is 2:1, that is, AABAAB.

[0044] Figure 4 Example 3 of the present invention is shown, in which metal material A and metal material B are deposited in sequence, the number of deposited layers is 13 layers, and the ratio of metal material A to metal material B is 3:1, that is, AAABAAAB.

Claims

1. A method for eliminating cracks in heterogeneous alloys based on a bionic structure, characterized by: The steps include: Step 1: Obtain the material type and density distribution information of the heterogeneous alloy at the crack, and adopt a bionic heterostructure with corresponding parameters. The density distribution information of the heterogeneous alloy includes the distribution direction and distribution density of the heterogeneous alloy; Step 2: Obtain the crack size, combine it with the bionic heterostructure parameters to generate a three-dimensional model of the bionic heterostructure for eliminating the crack, and perform printing preprocessing to generate layered contour data and deposition work path; the crack size includes crack length and crack depth, and the bionic heterostructure is a bionic orientation gradient structure; Step 3: Based on the generated layered profile data and deposition work path, the corresponding metal material is delivered in real time, and directed energy deposition is performed layer by layer to repair the original cracks into an intact surface with a bionic heterogeneous structure; Step 4: After cooling, perform a crack inspection on the crack-eliminated surface to ensure the crack elimination effect. If cracks still exist, repeat steps 1 to 3. A bionic orientation gradient structure is formed by spiral periodic arrangement. Different metal materials are used between each gradient according to the material density distribution. The materials of the bionic orientation gradient structure are metal material A and metal material B. Metal material A and metal material B are two metal materials of cracking heterogeneous alloy materials; Metal material A and metal material B are deposited on each other to generate a bionic orientation gradient structure; The bionic orientation gradient structure includes an ABA bionic orientation gradient structure, an AAB bionic orientation gradient structure or an AAAB bionic orientation gradient structure; During the directed energy deposition process, the printing directions of the bionic orientation gradient structures at the bottom and top layers of the crack are perpendicular to the crack extension direction.

2. The method for eliminating cracks in heterogeneous alloys based on a bionic structure according to claim 1, characterized in that: In step 3, during the directed energy deposition process, the printing process parameters are: The laser spot diameter is 1-3mm, the laser power is 400-600W, the print head scanning speed is 200-400mm / min, the powder feeding rate of the powder feeding bin is 10-30g / min, the protective gas flow rate is 8-12L / min, and the powder carrier gas flow rate is 8-13L / min.

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