Aluminum alloy heterostructure integrated forming method based on transition layer prefabrication
By introducing a high-strength aluminum alloy transition layer into aluminum-based silicon carbide materials and combining it with laser selective melting technology, the interface stress problem when connecting low-score and high-score aluminum-based silicon carbide materials is solved, and the manufacturing of high-precision integrated gradient structures of aluminum-based silicon carbide composite materials is achieved, which is suitable for aerospace and other fields.
Patent Information
- Application Number
- CN202510970378.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-15
- Publication Date
- 2025-09-05
AI Technical Summary
In the existing technology, when low-score and high-score aluminum-based silicon carbide materials are directly connected, the interface stress is large and the bonding strength is limited. Especially in high-temperature and high-stress environments, they are prone to breakage, making it difficult to achieve high-precision integrated gradient structures of aluminum-based silicon carbide composite materials.
By adopting the transition layer prefabrication method, the multi-material component structure is designed in finite element software, and the high-strength aluminum alloy transition layer is used to connect the high-score and low-score silicon carbide. 3D printing is performed in combination with laser selective melting technology to prepare aluminum alloy heterogeneous structures, including forming the matrix silicon carbide skeleton and infiltrating aluminum, and forming the transition layer layer by layer to achieve integrated forming.
The overall performance of low-score-high-score aluminum-based silicon carbide composites is achieved, interface stress and poor fusion are avoided, forming accuracy and design freedom are improved, and it is suitable for mass production of geometric gradient structures of high-low-score SiC/Al-based composites.
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Figure CN120587487A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of additive manufacturing, and in particular relates to an integrated forming method of an aluminum alloy heterogeneous structure based on prefabrication of a transition layer. Background Art
[0002] Aluminum-based silicon carbide composites hold significant promise for applications in advanced technologies such as aerospace and military applications due to their lightweight, high specific strength, high corrosion resistance, high elastic modulus, high wear resistance, and low thermal expansion coefficient. However, as service requirements for material structures increase, different materials often need to be selected for fabrication based on the varying load-bearing requirements of different component locations. Therefore, integrated gradient structures of low- and high-score aluminum-based silicon carbide materials present significant application value. The significant difference in SiC content between low-score (≤10 vol.%) and high-score (45 vol.%–60 vol.%) aluminum-based silicon carbide materials results in significant differences in thermophysical properties. Direct bonding generates significant interfacial stresses, which are detrimental to the performance of gradient components. Currently, brazing is often used to join dissimilar materials, but joint strength is affected by the physical properties of the brazing filler metal and the base metal, as well as the process parameters. Consequently, the performance of the joint is often inferior to that of the base metal itself, especially in high-temperature and high-stress environments, where fracture and failure may occur at this location. Therefore, the application of additive manufacturing technology to the fabrication of gradient materials is highly desirable. Additive manufacturing can achieve highly complex and customized geometric structures, free from the limitations of traditional processing methods, and has a high degree of design freedom. It can also achieve high-precision manufacturing and more accurate dimensional control of complex shapes and details. Summary of the Invention
[0003] The technical problem to be solved by the present invention is to provide an integrated forming method of aluminum alloy heterogeneous structure based on transition layer prefabrication in view of the deficiencies in the above-mentioned prior art.
[0004] To solve the above technical problems, the present invention adopts a technical solution: a method for integrated forming of an aluminum alloy heterogeneous structure based on prefabrication of a transition layer, characterized in that the method comprises the following steps: Step 1: Design the multi-material component structure: Construct the high-score silicon carbide and low-score silicon carbide of the multi-material component in finite element software, and use a transition layer to connect the high-score silicon carbide and the low-score silicon carbide; Step 2: Forming a matrix silicon carbide skeleton and infiltrating aluminum alloy to form high-score silicon carbide: Determine a homogeneous or gradient matrix silicon carbide skeleton, select silicon carbide particles in the additively manufactured silicon carbide blank according to the required silicon carbide solid content, select a binder, form a homogeneous or gradient matrix silicon carbide skeleton layer by layer, and infiltrate the obtained homogeneous or gradient matrix silicon carbide skeleton with aluminum alloy to obtain a homogeneous or gradient high-score silicon carbide with a designed aluminum alloy volume fraction; Step 3: Prefabricate a transition layer according to the component structure: prefabricate a transition layer at the interface where the high-score silicon carbide and the low-score silicon carbide are to be connected, wherein the transition layer is a high-strength aluminum alloy transition layer; Step 4: SLM forming of low-score silicon carbide aluminum-based composite materials: Using a high-strength aluminum alloy transition layer as the forming substrate, the low-score silicon carbide aluminum-based composite powder is clad on the prefabricated transition layer using laser selective melting technology for 3D printing.
[0005] The above-mentioned method for integrated forming of aluminum alloy heterogeneous structures based on prefabrication of a transition layer is characterized in that: in step 1, high-score silicon carbide and low-score silicon carbide of a multi-material component are constructed in finite element software, and the high-score silicon carbide and low-score silicon carbide are connected by a transition layer. The process of preparing the transition layer includes the following steps: Step 101: Determine the process parameters of the selective laser melting technology in step 4, wherein the process parameters of the selective laser melting technology include laser power, scanning speed, scanning spacing, and powder layer thickness; Step 102: According to the formula , determine the thickness of the transition layer ,in, is the correlation coefficient, is the laser input energy density and , is the laser power, is the scanning speed, is the scanning distance, To make the powder layer thick; Determine the thickness of the transition layer When constructing a multi-material component with high-score silicon carbide and low-score silicon carbide in the finite element software, the high-score silicon carbide and low-score silicon carbide are connected using a transition layer with a gradient thickness. The boundary conditions of the constructed connected multi-material components are input to determine the trend and range of the correlation coefficient, and then the thickness of the transition layer is determined. The limiting boundaries include the size of the multi-material component, the mass of the multi-material component, the temperature transfer effect of the multi-material component and the overall performance of the multi-material component.
[0006] The above-mentioned aluminum alloy heterostructure integrated forming method based on transition layer prefabrication is characterized in that: in step 2, the process of forming the matrix silicon carbide skeleton and infiltrating the aluminum alloy to form high-scoring silicon carbide includes the following steps: Step 201: Selecting the solid content W of SiC in the additively manufactured SiC blank as w vol % (45<w<60) as needed; Step 202: Designing a SiC skeleton structure to be printed, wherein the skeleton is a lattice structure, a lattice structure, or a frame structure; Step 203: Select raw materials SiC particles, binder, and resin, introduce the designed SiC skeleton into the additive manufacturing equipment system, and form the SiC blank of the desired structure layer by layer. The forming technology includes light-stereolithography 3D printing, selective laser sintering, ink direct writing, and fused deposition modeling; Step 204: Degreasing and sintering the SiC skeleton body formed by additive manufacturing in step 203, wherein the degreasing temperature is 400° C. to 650° C., the heating rate in the degreasing stage shall not exceed 1.5° C. / min, the sintering temperature is 1200° C. to 1600° C., the sintering time is 1 hour to 3 hours, and the degreasing and sintering atmosphere is a single gas or a mixed gas of nitrogen, argon, and air; Step 205: performing surface strengthening treatment on the SiC skeleton, wherein the treatment methods include oxidation treatment and chemical vapor infiltration; Step 206: The SiC skeleton obtained in step 205 is subjected to aluminum alloy infiltration treatment to obtain homogeneous or gradient high-fraction silicon carbide with a designed aluminum alloy volume fraction.
[0007] The above-mentioned aluminum alloy heterogeneous structure integrated forming method based on transition layer prefabrication is characterized in that: in step 3, when the transition layer is prefabricated at the interface position of high-score silicon carbide and low-score silicon carbide to be connected, the high-score silicon carbide at the corresponding position in step 2 is aluminized in place and then aluminized processing is continued to obtain an integrated aluminized processing allowance as a high-strength aluminum alloy transition layer, and the thickness of the high-strength aluminum alloy transition layer is the transition layer thickness determined in step 1 If the thickness of the integral aluminizing machining allowance is greater than When grinding, the transition layer thickness is reduced to Meet the requirements.
[0008] The above-mentioned method for integrated forming of aluminum alloy heterostructures based on transition layer prefabrication is characterized in that: in step 4, the volume fraction of silicon carbide in the low-score silicon carbide aluminum-based composite powder is in the range of 5 vol% to 10 vol%.
[0009] The above-mentioned aluminum alloy heterostructure integrated forming method based on prefabricated transition layer is characterized in that: before starting step 4, the mixed powder is dried in a vacuum drying oven at 120°C for 3 hours in preparation for use, the surface of the forming substrate is cleaned with anhydrous ethanol to remove oil stains, and the forming substrate is preheated to 80°C to reduce the influence of stress; The remelting technology SLM is used to form low-score silicon carbide aluminum-based composite materials. The angle between each laser scanning path in the remelting path and the previous scanning path differs by 67°. This is used to eliminate the strip protrusions caused by the overlap of the remelting path and the previous scanning path, which in turn causes tool jamming failure and eliminates residual stress in the sample. The remelting parameter selection scanning speed is 200 mm / s higher than the previous cladding scanning speed. The other parameters are consistent with the process parameters of the laser selective melting technology determined in step one. Finally, a multi-material integrated gradient formed component based on a prefabricated transition layer is obtained. The beneficial effects of the present invention are that, according to the component structure, a transition layer is prefabricated at the interface position of the high-score silicon carbide and the low-score silicon carbide to be connected, the transition layer is a high-strength aluminum alloy transition layer, which has efficient heat conduction while meeting the overall performance of the multi-material component, and realizes the integrated gradient forming of the low-score-high-score aluminum-based silicon carbide composite material, avoids defects such as interface stress and poor interface fusion caused by direct connection through additive manufacturing technology, is not restricted by traditional processing methods, has a high degree of design freedom, and a wide range of applications. It can realize the mass production of high-low-score SiC / Al-based composite material geometric gradient structures, has high production efficiency and high forming accuracy, has good application prospects, and is easy to promote and use.
[0010] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Figure 1 It is a flowchart of the method of the present invention. DETAILED DESCRIPTION
[0012] like Figure 1 As shown, the present invention provides an integrated forming method of an aluminum alloy heterogeneous structure based on prefabrication of a transition layer, comprising the following steps: Step 1: Design the multi-material component structure: Construct the high-score silicon carbide and low-score silicon carbide of the multi-material component in finite element software, and use a transition layer to connect the high-score silicon carbide and the low-score silicon carbide; Step 2: Forming a matrix silicon carbide skeleton and infiltrating aluminum alloy to form high-score silicon carbide: Determine a homogeneous or gradient matrix silicon carbide skeleton, select silicon carbide particles in the additively manufactured silicon carbide blank according to the required silicon carbide solid content, select a binder, form a homogeneous or gradient matrix silicon carbide skeleton layer by layer, and infiltrate the obtained homogeneous or gradient matrix silicon carbide skeleton with aluminum alloy to obtain a homogeneous or gradient high-score silicon carbide with a designed aluminum alloy volume fraction; Step 3: Prefabricate a transition layer according to the component structure: prefabricate a transition layer at the interface where the high-score silicon carbide and the low-score silicon carbide are to be connected, wherein the transition layer is a high-strength aluminum alloy transition layer; Step 4: SLM forming of low-score silicon carbide aluminum-based composite materials: Using a high-strength aluminum alloy transition layer as the forming substrate, the low-score silicon carbide aluminum-based composite powder is clad on the prefabricated transition layer using laser selective melting technology for 3D printing.
[0013] It should be noted that, according to the component structure, a transition layer is prefabricated at the interface between high-score silicon carbide and low-score silicon carbide to be connected. The transition layer is a high-strength aluminum alloy transition layer, which can efficiently conduct heat while meeting the overall performance of the multi-material component, realizing the integrated gradient forming of low-score-high-score aluminum-based silicon carbide composite materials, avoiding defects such as interface stress and poor interface fusion caused by direct connection through additive manufacturing technology, and is not restricted by traditional processing methods. It has a high degree of design freedom and a wide range of applications. It can realize mass production of geometric gradient structures of high-low-score SiC / Al-based composite materials with high production efficiency and high forming accuracy, and has good application prospects.
[0014] In this embodiment, in step 1, high-score silicon carbide and low-score silicon carbide of a multi-material component are constructed in finite element software, and a transition layer is used to connect the high-score silicon carbide and the low-score silicon carbide. The process of preparing the transition layer includes the following steps: Step 101: Determine the process parameters of the selective laser melting technology in step 4, wherein the process parameters of the selective laser melting technology include laser power, scanning speed, scanning spacing, and powder layer thickness; Step 102: According to the formula , determine the thickness of the transition layer ,in, is the correlation coefficient, is the laser input energy density and , is the laser power, is the scanning speed, is the scanning distance, To make the powder layer thick; Determine the thickness of the transition layer When constructing a multi-material component with high-score silicon carbide and low-score silicon carbide in the finite element software, the high-score silicon carbide and low-score silicon carbide are connected using a transition layer with a gradient thickness. The boundary conditions of the constructed connected multi-material components are input to determine the trend and range of the correlation coefficient, and then the thickness of the transition layer is determined. The limiting boundaries include the size of the multi-material component, the mass of the multi-material component, the temperature transfer effect of the multi-material component and the overall performance of the multi-material component.
[0015] In this embodiment, in step 2, the process of forming a matrix silicon carbide skeleton and infiltrating aluminum alloy to form high-scoring silicon carbide includes the following steps: Step 201: Selecting the solid content W of SiC in the additively manufactured SiC blank as w vol % (45<w<60) as needed; Step 202: Designing a SiC skeleton structure to be printed, wherein the skeleton is a lattice structure, a lattice structure, or a frame structure; Step 203: Select raw materials SiC particles, binder, and resin, introduce the designed SiC skeleton into the additive manufacturing equipment system, and form the SiC blank of the desired structure layer by layer. The forming technology includes light-stereolithography 3D printing, selective laser sintering, ink direct writing, and fused deposition modeling; Step 204: Degreasing and sintering the SiC skeleton body formed by additive manufacturing in step 203, wherein the degreasing temperature is 400° C. to 650° C., the heating rate in the degreasing stage shall not exceed 1.5° C. / min, the sintering temperature is 1200° C. to 1600° C., the sintering time is 1 hour to 3 hours, and the degreasing and sintering atmosphere is a single gas or a mixed gas of nitrogen, argon, and air; Step 205: performing surface strengthening treatment on the SiC skeleton, wherein the treatment methods include oxidation treatment and chemical vapor infiltration; Step 206: The SiC skeleton obtained in step 205 is subjected to aluminum alloy infiltration treatment to obtain homogeneous or gradient high-fraction silicon carbide with a designed aluminum alloy volume fraction.
[0016] It should be noted that a transition layer is prefabricated at the interface between high-score silicon carbide and low-score silicon carbide to be connected. The stress concentration phenomenon corresponding to different thicknesses under heat input is different. Experiments are carried out on different epitaxial aluminum alloy thicknesses. The transition layer has different bonding conditions with the high-score aluminum-based composite. When the transition layer is too thin, warping and deformation occur, and the transition layer is separated from the high-score aluminum-based composite. When the transition layer is too thick, the overall performance of the multi-material component decreases. Therefore, the thickness of the transition layer is determined. It is crucial to use a transition layer with a gradient thickness to connect high-score silicon carbide and low-score silicon carbide, which can intuitively determine the trend and range of the correlation coefficient at one time, and then determine the thickness of the epitaxial growth transition layer. scope.
[0017] In this embodiment, in step 3, when a transition layer is prefabricated at the interface position of the high-score silicon carbide and the low-score silicon carbide to be connected, the high-score silicon carbide at the corresponding position in step 2 is aluminized in place and then aluminized processing is continued to obtain an integrated aluminized processing allowance as a high-strength aluminum alloy transition layer. The thickness of the high-strength aluminum alloy transition layer is the thickness of the transition layer determined in step 1. If the thickness of the integral aluminizing machining allowance is greater than When grinding, the transition layer thickness is reduced to Meet the requirements.
[0018] In this embodiment, in step 4, the volume fraction of silicon carbide in the low-score silicon carbide aluminum-based composite powder is in the range of 5 vol% to 10 vol%.
[0019] In this embodiment, before starting step 4, the mixed powder is dried in a vacuum drying oven at 120°C for 3 hours in preparation for use. The surface of the forming substrate is cleaned with anhydrous ethanol to remove oil stains. To reduce the influence of stress, the forming substrate is preheated at 80°C. The remelting technology SLM is used to form low-score silicon carbide aluminum-based composite materials. The angle between each laser scanning path in the remelting path and the previous scanning path differs by 67°. This is used to eliminate the strip protrusions caused by the overlap of the remelting path and the previous scanning path, which in turn causes tool jamming failure and eliminates residual stress in the sample. The remelting parameter selection scanning speed is 200 mm / s higher than the previous cladding scanning speed. The other parameters are consistent with the process parameters of the laser selective melting technology determined in step one. Finally, a multi-material integrated gradient formed component based on a prefabricated transition layer is obtained.
[0020] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent structural change made to the above embodiment based on the technical essence of the present invention shall still fall within the scope of protection of the technical solution of the present invention.
Claims
1. A method for integrated forming of aluminum alloy heterogeneous structures based on prefabrication of transition layers, characterized in that: The method comprises the following steps: Step 1: Design the multi-material component structure: Construct the high-score silicon carbide and low-score silicon carbide of the multi-material component in finite element software, and use a transition layer to connect the high-score silicon carbide and the low-score silicon carbide; Step 2: Forming a matrix silicon carbide skeleton and infiltrating aluminum alloy to form high-score silicon carbide: Determine a homogeneous or gradient matrix silicon carbide skeleton, select silicon carbide particles in the additively manufactured silicon carbide blank according to the required silicon carbide solid content, select a binder, form a homogeneous or gradient matrix silicon carbide skeleton layer by layer, and infiltrate the obtained homogeneous or gradient matrix silicon carbide skeleton with aluminum alloy to obtain a homogeneous or gradient high-score silicon carbide with a designed aluminum alloy volume fraction; Step 3: Prefabricate a transition layer according to the component structure: prefabricate a transition layer at the interface where the high-score silicon carbide and the low-score silicon carbide are to be connected, wherein the transition layer is a high-strength aluminum alloy transition layer; Step 4: SLM forming of low-score silicon carbide aluminum-based composite materials: Using a high-strength aluminum alloy transition layer as the forming substrate, the low-score silicon carbide aluminum-based composite powder is clad on the prefabricated transition layer using laser selective melting technology for 3D printing.
2. The method for integrated forming of an aluminum alloy heterogeneous structure based on prefabrication of a transition layer according to claim 1, characterized in that: In step 1, high-score silicon carbide and low-score silicon carbide of a multi-material component are constructed in finite element software, and a transition layer is used to connect the high-score silicon carbide and the low-score silicon carbide. The process of preparing the transition layer includes the following steps: Step 101: Determine the process parameters of the selective laser melting technology in step 4, wherein the process parameters of the selective laser melting technology include laser power, scanning speed, scanning spacing, and powder layer thickness; Step 102: According to the formula , determine the thickness of the transition layer ,in, is the correlation coefficient, is the laser input energy density and , is the laser power, is the scanning speed, is the scanning distance, To make the powder layer thick; Determine the thickness of the transition layer When constructing a multi-material component with high-score silicon carbide and low-score silicon carbide in the finite element software, the high-score silicon carbide and low-score silicon carbide are connected using a transition layer with a gradient thickness. The boundary conditions of the constructed connected multi-material components are input to determine the trend and range of the correlation coefficient, and then the thickness of the transition layer is determined. The limiting boundaries include the size of the multi-material component, the mass of the multi-material component, the temperature transfer effect of the multi-material component and the overall performance of the multi-material component.
3. The method for integrated forming of an aluminum alloy heterogeneous structure based on prefabrication of a transition layer according to claim 1, characterized in that: In step 2, the process of forming a matrix silicon carbide skeleton and infiltrating aluminum alloy to form high-scoring silicon carbide includes the following steps: Step 201: Selecting the solid content W of SiC in the additively manufactured SiC blank as w vol % (45<w<60) as needed; Step 202: Designing a SiC skeleton structure to be printed, wherein the skeleton is a lattice structure, a lattice structure, or a frame structure; Step 203: Select raw materials SiC particles, binder, and resin, introduce the designed SiC skeleton into the additive manufacturing equipment system, and form the SiC blank of the desired structure layer by layer. The forming technology includes light-stereolithography 3D printing, selective laser sintering, ink direct writing, and fused deposition modeling; Step 204: Degreasing and sintering the SiC skeleton body formed by additive manufacturing in step 203, wherein the degreasing temperature is 400° C. to 650° C., the heating rate in the degreasing stage shall not exceed 1.5° C. / min, the sintering temperature is 1200° C. to 1600° C., the sintering time is 1 hour to 3 hours, and the degreasing and sintering atmosphere is a single gas or a mixed gas of nitrogen, argon, and air; Step 205: performing surface strengthening treatment on the SiC skeleton, wherein the treatment methods include oxidation treatment and chemical vapor infiltration; Step 206: The SiC skeleton obtained in step 205 is subjected to aluminum alloy infiltration treatment to obtain homogeneous or gradient high-fraction silicon carbide with a designed aluminum alloy volume fraction.
4. The method for integrated forming of an aluminum alloy heterogeneous structure based on prefabrication of a transition layer according to claim 2, characterized in that: In step 3, when a transition layer is prefabricated at the interface position of the high-score silicon carbide and the low-score silicon carbide to be connected, the high-score silicon carbide at the corresponding position in step 2 is aluminized in place and then aluminized to obtain an integral aluminized processing allowance as a high-strength aluminum alloy transition layer. The thickness of the high-strength aluminum alloy transition layer is the thickness of the transition layer determined in step 1. If the thickness of the integral aluminizing machining allowance is greater than When grinding, the transition layer thickness is reduced to Meet the requirements.
5. The method for integrated forming of an aluminum alloy heterogeneous structure based on prefabrication of a transition layer according to claim 1, characterized in that: In step 4, the volume fraction of silicon carbide in the low-score silicon carbide aluminum-based composite powder is in the range of 5 vol% to 10 vol%.
6. The method for integrated forming of an aluminum alloy heterogeneous structure based on prefabrication of a transition layer according to claim 5, characterized in that: Before starting step 4, the mixed powder needs to be dried in a vacuum drying oven at 120°C for 3 hours before use. The surface of the forming substrate is cleaned with anhydrous ethanol to remove oil stains. To reduce the influence of stress, the forming substrate is preheated at 80°C. The remelting technology SLM is used to form low-score silicon carbide aluminum-based composite materials. The angle between each laser scanning path in the remelting path and the previous scanning path differs by 67°. This is used to eliminate the strip protrusions caused by the overlap of the remelting path and the previous scanning path, which in turn causes tool jamming failure and eliminates residual stress in the sample. The remelting parameter selection scanning speed is 200 mm / s higher than the previous cladding scanning speed. The other parameters are consistent with the process parameters of the laser selective melting technology determined in step one. Finally, a multi-material integrated gradient formed component based on a prefabricated transition layer is obtained.