Method for eliminating heterogeneous alloy cracks based on bionic structure

Abstract

The invention discloses a method for eliminating a heterogeneous alloy crack based on a bionic structure, and relates to the technical field of additive manufacturing, and the method comprises the following steps: step 1, obtaining the material type and density distribution information of a heterogeneous alloy at the crack, and adopting a bionic heterostructure with corresponding parameters; 2, the crack size is obtained, a bionic heterostructure three-dimensional model used for eliminating cracks is generated in combination with bionic heterostructure parameters, printing pretreatment is conducted, and layered contour data and a deposition working path are generated; 3, according to the generated layered contour data and the deposition working path, corresponding metal materials are conveyed in real time, directional energy deposition forming is carried out layer by layer, and the original crack position is repaired to be an intact surface with a bionic heterostructure; after the crack is eliminated by adopting the method, the crack can be effectively inhibited from continuously extending towards other directions, meanwhile, the surface strength of the material can be enhanced to a certain extent, and the problem of cracking of heterogeneous alloy manufactured by laser cladding can be well solved.

Description

Technical Field

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

[0002] Directed energy deposition (laser cladding) is a laser additive manufacturing process in which raw materials in the form of powder or wire are delivered to a substrate that simultaneously focuses an energy source such as a laser beam, electron beam, or plasma arc to form a small molten pool and continuously deposit materials layer by layer. Heterogeneous alloy materials are materials composed of two or more different metals and have unique physical and chemical properties that ordinary alloys do not have. The performance of heterogeneous alloy materials depends on their metal composition and the unique internal structure. The unique structure of heterogeneous alloys is difficult to achieve through traditional manufacturing methods, and directed energy deposition has strong applicability in repairing and manufacturing heterogeneous alloys due to its manufacturing principle of forming a molten pool. At present, many studies have used the manufacturing method of directed energy deposition to manufacture alloys with uniform and precise heterogeneous structures, achieving a huge improvement in the performance of heterogeneous alloy materials. Metal materials manufactured and remanufactured by laser cladding technology can form reinforced materials with excellent properties such as higher strength and better ductility, and have far-reaching application potential in various industrial fields.

[0003] In actual engineering applications, many heterogeneous alloy manufacturing and heterogeneous alloy welding joints have cracking problems. In particular, the liquefaction cracks, solidification cracks, and solid cracks that occur in the manufacturing process of space heterogeneous alloys have seriously affected the application of heterogeneous alloy materials. Therefore, avoiding and eliminating its cracks is also the focus of related research. In recent years, with the development of bionic heterostructure research, heterogeneous alloy crack elimination technology that imitates biological heterostructures is expected to efficiently repair 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 cracks in heterogeneous alloys. 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: Step 1: Obtain the material type and density distribution information of the heterogeneous alloy at the crack, and adopt a bionic heterogeneous structure with corresponding parameters; Step 2: Obtain the crack size, generate a bionic heterostructure three-dimensional model for eliminating cracks in combination with bionic heterostructure parameters, and perform printing preprocessing to generate layered contour data and deposition work path; Step 3: According to the generated layered profile data and deposition work path, the corresponding metal material is transported in real time, and directed energy deposition is performed layer by layer to repair the original cracks into a complete surface with a bionic heterogeneous structure; 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.

[0006] Preferably, the density distribution information of the heterogeneous alloy in step 1 includes the distribution direction and distribution density of the heterogeneous alloy.

[0007] Preferably, the crack size in step 2 includes crack length and crack depth.

[0008] Preferably, the bionic heterostructure used in step 2 is a bionic orientation gradient structure.

[0009] Preferably, 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.

[0010] 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.

[0011] Beneficial effects of the present invention: The present invention can effectively control the bonding strength and density between various metals, providing more convenience for the design of heterogeneous alloys; By using laser cladding manufacturing method, a bionic heterostructure is constructed at the crack, which can effectively eliminate the cracks in heterogeneous alloys, and the stability is good after repair; After eliminating cracks using this method, the cracks can be effectively inhibited from extending further in other directions. At the same time, the surface strength of the material can be enhanced 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

[0012] Figure 1 This is a schematic diagram of the bionic orientation gradient structure of the present invention; Figure 2 A schematic diagram of crack elimination of a bionic orientation gradient structure with a material density distribution of 1:1 according to the present invention; Figure 3 A schematic diagram of crack elimination of a bionic orientation gradient structure with a material density distribution of 2:1 according to the present invention; Figure 4 Schematic diagram of crack elimination of the bionic orientation gradient structure with a material density distribution of 3:1 in the present invention. DETAILED DESCRIPTION

[0013] In order to make the purpose, processing design scheme and advantages of the embodiments of the present application clearer, the design scheme and manufacturing method in the embodiments of the present application will be clearly and completely described below in conjunction with the embodiment drawings in the present application.

[0014] A method for eliminating cracks in heterogeneous alloys based on a bionic structure comprises the following steps: Step 1: Obtain the material type and density distribution information of the heterogeneous alloy at the crack, and adopt a bionic heterogeneous structure with corresponding parameters; Step 2: Obtain the crack size, combine the bionic heterostructure parameters to generate a bionic heterostructure three-dimensional model for eliminating cracks, and perform printing preprocessing, i.e., slicing processing, to generate layered contour data and deposition work path; 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: Laser spot diameter 1-3mm, laser power 400-600W, print head scanning speed 200-400mm / min, powder feeding rate of powder feeding bin 10-30g / min, protective gas flow rate 8-12L / min, powder carrier gas flow rate 8-13L / min; Repair the original cracks to a sound surface with a bionic heterostructure; 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.

[0015] Furthermore, the crack size in step 2 includes crack length and crack depth.

[0016] Furthermore, the bionic heterostructure used in step 2 is a bionic orientation gradient structure.

[0017] 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.

[0018] like Figure 1As 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 in 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.

[0019] In order to facilitate the understanding of the present invention, the following examples are given: 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; Among them, the bionic orientation gradient structure includes ABA bionic orientation gradient structure, AAB bionic orientation gradient structure, and AAAB bionic orientation gradient structure.

[0020] Different parameters of bionic orientation gradient structure are used for heterogeneous alloy materials with different distribution densities; Figure 2 Embodiment 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 layers, and the ratio of metal material A to metal material B is 1:1, namely ABAB.

[0021] Figure 3 Embodiment 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 layers, and the ratio of metal material A to metal material B is 2:1, that is, AABAAB.

[0022] Figure 4 Embodiment 3 of the present invention is shown, in which metal material A and metal material B are deposited sequentially, 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 in that: The steps include: Step 1: Obtain the material type and density distribution information of the heterogeneous alloy at the crack, and adopt a bionic heterogeneous structure with corresponding parameters; Step 2: Obtain the crack size, generate a bionic heterostructure three-dimensional model for eliminating cracks in combination with bionic heterostructure parameters, and perform printing preprocessing to generate layered contour data and deposition work path; Step 3: According to the generated layered profile data and deposition work path, the corresponding metal material is transported in real time, and directed energy deposition is performed layer by layer to repair the original cracks into a complete surface with a bionic heterogeneous structure; 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.

2. The method for eliminating cracks in heterogeneous alloys based on bionic structure according to claim 1, characterized in that: The density distribution information of the heterogeneous alloy in the step 1 includes the distribution direction and the distribution density of the heterogeneous alloy.

3. The method for eliminating cracks in heterogeneous alloys based on bionic structure according to claim 1, characterized in that: The crack size in step 2 includes crack length and crack depth.

4. The method for eliminating cracks in heterogeneous alloys based on bionic structure according to claim 1, characterized in that: The bionic heterostructure used in step 2 is a bionic orientation gradient structure.

5. The method for eliminating cracks in heterogeneous alloys based on bionic structure according to claim 4, 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.

6. The method for eliminating cracks in heterogeneous alloys based on bionic structure according to claim 5, characterized in that: During the directed energy deposition process, the printing direction of the bionic orientation gradient structure at the bottom and top layers of the crack is perpendicular to the crack extension direction.

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