Titanium alloy-nickel-titanium alloy heterogeneous material adopting bionic shell microstructure interface and preparation method of titanium alloy-nickel-titanium alloy heterogeneous material
By using biomimetic seashell microstructure interfaces and laser powder bed melting technology, the problem of low bonding strength between titanium alloys and nickel-titanium alloys has been solved, realizing the forming of heterogeneous materials with high bonding strength, which is suitable for aerospace and medical equipment fields.
Patent Information
- Application Number
- CN202510921444.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-04
- Publication Date
- 2025-11-21
AI Technical Summary
Titanium alloys and nickel-titanium alloys have differences in thermal and chemical properties at the interface, resulting in low interfacial bonding strength and easy formation of inclusions, cracks and brittle intermetallic compounds, making it difficult to achieve high bonding strength in the forming of heterogeneous material components using existing processes.
By employing a biomimetic seashell microstructure interface, titanium alloys and nickel-titanium alloys are formed layer by layer using laser powder bed melting technology. The periodicity and isotropic characteristics of the biomimetic seashell microstructure are utilized to disperse interfacial thermal stress, reduce cracks and defects, and achieve a good metallurgical bond.
It effectively disperses interfacial thermal stress, improves interfacial bonding strength, reduces cracks and defects, and enables the forming of titanium alloy-nickel titanium alloy heterostructures with high bonding strength, which are suitable for aerospace, medical equipment and other fields.
Smart Images
Figure CN120984894A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of additive manufacturing technology for metal components, specifically relating to a titanium alloy-nickel titanium alloy heterostructure material with a biomimetic seashell microstructure interface and its preparation method. Background Technology
[0002] NiTi shape memory alloys possess shape memory effect, superelasticity, and high damping properties, making them widely used in biomedicine, aerospace, and seismic damping devices. In addition to these properties, NiTi alloys also exhibit good fatigue resistance and corrosion resistance, further enhancing their applicability. Titanium alloys, due to their excellent strength, toughness, fatigue resistance, corrosion resistance, and biocompatibility, can also be applied in the aforementioned fields. Ti6Al4V is the most widely used titanium alloy in aerospace, civilian, chemical, and biomedical fields. Therefore, these two materials can be integrated into complex structural components from multiple parts in biomedical applications, leading to the development of titanium alloy-nickel-titanium alloy heterostructures. However, forming titanium alloy-nickel-titanium alloy heterostructures presents numerous challenges.
[0003] Titanium alloys and nickel-titanium alloys differ significantly in their thermophysical and chemical properties, and currently used titanium alloy-nickel-titanium alloy joining processes often face the following challenges: ①Titanium is a reactive metal, and its surface is easily oxidized to form dense TiO2, which can easily produce defects such as inclusions and cracks, reducing the metallurgical bonding strength of the interface. ②The lattice type, lattice parameters and atomic structure of titanium alloys and nickel-titanium alloys are significantly different, which leads to significant differences in the coefficient of linear expansion and thermal conductivity of the two alloys. The interface is difficult to bond and is prone to interfacial cracks. ③ Metallurgical reactions occur at the titanium alloy-nickel titanium alloy interface, which readily generate brittle intermetallic compounds such as Ti2Ni, Ti3Ni and Al3Ti. The properties and thickness of the brittle intermetallic compounds directly determine the interfacial bonding strength of the titanium alloy-nickel titanium alloy.
[0004] These challenges urgently require new processes to solve, and further development of applications for titanium alloy-nickel titanium alloy heterogeneous material components.
[0005] In recent years, Laser Powder Bed Fusion (LPBF) has demonstrated unique advantages over other additive manufacturing processes in forming metal components. LPBF can manufacture high-precision metal components, meeting the high-precision machining requirements of complex parts; it allows for precise control of processing parameters, ensuring the quality and performance of the formed parts; it can produce metal components with complex structures, meeting the needs of aerospace and other fields; it offers rapid production speeds, reducing product production cycles and improving production efficiency; and it allows for precise control and utilization of materials, reducing material waste and saving production costs. However, due to the differences in thermal properties between titanium alloys and nickel-titanium alloys, there is an urgent need to research a new forming method to meet the requirements of LPBF forming of titanium alloy-nickel-titanium alloy heterogeneous material components. Summary of the Invention
[0006] Technical Problem Solved: To address the aforementioned technical problems, this invention provides a titanium alloy-nickel titanium alloy heterostructure material with a biomimetic shell microstructure interface and its preparation method. This solves the interface problems caused by excessive residual stress at the interface of the titanium alloy-nickel titanium alloy heterostructure material during laser powder fusion, which leads to cracks and defects in the intermetallic compound at the interface. The final product is a titanium alloy-nickel titanium alloy heterostructure material with good metallurgical bonding, no cracks, and high bonding strength.
[0007] Technical solution: A method for preparing titanium alloy-nickel titanium alloy heterostructure materials using a biomimetic seashell microstructure interface, comprising the following steps: S1. Establish a model of the titanium alloy base part. Take several seed points in the top surface area of the part. Connect two adjacent seed points and draw a perpendicular bisector on the connection line. The intersection of the perpendicular bisectors is used as the vertex of the biomimetic shell microstructure. The intersection of the perpendicular bisector and the boundary of the top surface area of the part is also used as the vertex of the biomimetic shell microstructure. Connect all vertices along the direction of the perpendicular bisector to obtain several closed graphic units. The overall pattern formed by all the closed graphic units is used as the interface pattern of the biomimetic shell microstructure. Extrude the area where some of the closed graphic units are located to obtain a complete three-dimensional model of the titanium alloy part. S2. Stretch the area containing the other closed graphic units that were not stretched in S1 to the same height to obtain a three-dimensional model of the biomimetic shell microstructure. On the three-dimensional model of the biomimetic shell microstructure, build a three-dimensional model of the nickel-titanium alloy part. S3. Laser path planning was performed on the 3D models of titanium alloy parts, biomimetic shell microstructures, and nickel-titanium alloy parts to obtain three processing files: titanium alloy, biomimetic shell microstructure, and nickel-titanium alloy. S4. Import the three processing files into the laser powder bed system, read the titanium alloy processing file, and melt and solidify the laid titanium alloy powder layer by layer with laser to form a titanium alloy part. S5. Clean the titanium alloy powder into the recovery cylinder of the laser powder bed, then spread nickel-titanium alloy powder, read the biomimetic shell microstructure processing file, and melt and solidify part of the nickel-titanium alloy powder layer by layer by laser to form the biomimetic shell microstructure part. S6. Read the nickel-titanium alloy processing file, and use laser to melt and solidify the remaining nickel-titanium alloy powder layer by layer to form a nickel-titanium alloy part, thereby obtaining the titanium alloy-nickel-titanium alloy heteromaterial.
[0008] Preferably, in step S1, the number of seed points is 28, and the seed point distribution is selected as a regular distribution.
[0009] Preferably, in S1, the distribution positions of some closed graphic units are randomly distributed.
[0010] Preferably, in S1, the total area occupied by the partially enclosed graphic units is half the area of the top surface of the part.
[0011] Preferably, in S1 and S2, the stretching height is 30 μm.
[0012] Preferably, in step S4, the laser power used to melt and solidify the titanium alloy powder in the laser powder bed is 175W, the laser scanning speed is 950mm / s, the scanning spacing is 50μm, and the powder thickness is 30μm.
[0013] Preferably, in S5 and S6, the laser power used to melt and solidify the nickel-titanium alloy powder in the laser powder bed is 105W, the laser scanning speed is 1400mm / s, the scanning spacing is 50μm, and the powder thickness is 30μm.
[0014] The titanium alloy-nickel titanium alloy heterostructure material with a biomimetic shell microstructure interface was prepared by the above method.
[0015] Beneficial effects: This invention uses a biomimetic shell-layer heterogeneous material microstructure to disperse interfacial thermal stress at the titanium alloy-nickel-titanium alloy interface, solving the interfacial problems such as cracks and defects caused by excessive residual stress at the titanium alloy-nickel-titanium alloy heterogeneous material interface during laser powder fusion, and ultimately forming a titanium alloy-nickel-titanium alloy heterogeneous material with good metallurgical bonding, no cracks and high bonding strength.
[0016] Compared to conventional triangular and square microstructures, this invention utilizes a biomimetic shell microstructure to improve the interfacial formability of heterogeneous materials formed by laser additive manufacturing. During laser melting, the sharp corners of triangular microstructures are prone to forming pores due to insufficient melt flow; the right-angled areas of square microstructures are prone to forming pore defects due to incomplete powder melting or spheroidization effects; while the periodicity of the biomimetic shell microstructure units allows for a more uniform distribution of laser energy, thereby improving the formation of interfacial defects.
[0017] Compared to conventional triangular and square microstructures, this invention employs a biomimetic shell microstructure to further alleviate interfacial thermal stress in heterogeneous materials formed by laser additive manufacturing. The radius of curvature at the vertices of triangular microstructures tends to zero, leading to localized stress singularities; square microstructures exhibit both shear stress concentration and normal stress concentration at their right angles, forming combined critical points; while the isotropic nature of the units in the biomimetic shell microstructure results in a low stress concentration factor when loaded in any in-plane direction. Furthermore, this unit can effectively force multiple crack deflections. Therefore, this biomimetic shell microstructure can effectively disperse thermal stress at the interface of heterogeneous materials.
[0018] Compared to traditional welding, riveting, and tenoning processes for joining dissimilar materials, this invention utilizes laser powder bed fusion technology to integrally form dissimilar material components. It fully leverages the high degree of freedom inherent in laser additive manufacturing, reducing the number of connecting parts required for structural components, minimizing processing steps, and shortening production cycles. This achieves lightweight, integral forming of structural components. The formed structural components are suitable for the production of complex, dimensionally precise, and small-batch applications in aerospace, medical equipment, national military, and industrial automotive fields. Attached Figure Description
[0019] Figure 1 This is a schematic diagram of the interface of the titanium alloy-nickel titanium alloy heterostructure sample prepared in Example 1 using a biomimetic seashell microstructure interface. Figure 2 A schematic diagram of the interface of a titanium alloy-nickel titanium alloy heterostructure sample prepared for Comparative Example 1 without using an interlocking pattern interface. Figure 3 A schematic diagram of the interface of the titanium alloy-nickel titanium alloy heterostructure sample with an isotriangular pattern interface prepared for Comparative Example 2. Figure 4 A schematic diagram of the interface of the titanium alloy-nickel titanium alloy heteromaterial sample with a square patterned interface prepared for Comparative Example 3. Figure 5 This is a schematic diagram of the titanium alloy-nickel titanium alloy heterostructure sample prepared in Example 1, which uses a biomimetic seashell microstructure interface. Figure 6 A schematic diagram of the structure of the titanium alloy-nickel titanium alloy heterostructure sample prepared for Comparative Example 1 without using the interlocking pattern interface. Figure 7 A schematic diagram of the structure of the titanium alloy-nickel titanium alloy heterostructure sample with an isotriangular patterned interface prepared for Comparative Example 2. Figure 8 A schematic diagram of the structure of the titanium alloy-nickel titanium alloy heterostructure sample with a square patterned interface prepared for Comparative Example 3. Figure 9 The image shows the interface optical image of the titanium alloy-nickel titanium alloy heterostructure sample with a biomimetic shell microstructure interface prepared in Example 1. Figure 10 Optical images of the interface of the titanium alloy-nickel titanium alloy heterostructure sample prepared for Comparative Example 1 without the use of interlocking patterned interfaces. Figure 11 Optical images of the interface of the titanium alloy-nickel titanium alloy heterostructure sample with an isotriangular patterned interface prepared for Comparative Example 2. Figure 12 An optical image of the interface of a titanium alloy-nickel titanium alloy heterostructure sample with a square patterned interface, prepared for Comparative Example 3. Detailed Implementation
[0020] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.
[0021] In the following examples and comparative examples, the titanium alloy powder used was Ti6Al4V, wherein the Al content was 5.5~6.5wt%, the V content was 3.5~4.5wt%, and the balance was Ti; the nickel-titanium alloy powder used was NiTi, wherein the Ni content was 50.5~51.5wt%, and the balance was Ti. Example 1
[0022] This embodiment discloses a method for preparing a titanium alloy-nickel titanium alloy heterostructure material using a biomimetic seashell microstructure interface, including the following steps: S1. First, use Unigraphics software to create a model of the titanium alloy base part. Then, sketch the top surface of the part and take several seed points in the area. Connect two adjacent seed points and draw perpendicular bisectors on the connecting lines. The intersection of the perpendicular bisectors is used as the vertex of the biomimetic shell microstructure. The intersection of the perpendicular bisectors and the boundary of the top surface area of the part is also used as the vertex of the biomimetic shell microstructure. Connect all vertices along the direction of the perpendicular bisectors to obtain several closed graphic units. The overall pattern formed by all the closed graphic units is used as the interface pattern of the biomimetic shell microstructure. Extrude the area where some of the closed graphic units are located to obtain the complete three-dimensional model of the titanium alloy part. The number of seed points is 28, and the distribution of seed points is selected according to a regular distribution. The distribution of some closed graphic units is random, and the total area occupied by some closed graphic units is half of the area of the top surface of the part.
[0023] S2. After the three-dimensional model of the titanium alloy part is established, the area where the other closed graphic units in S1 are not stretched is stretched to the same height to obtain the three-dimensional model of the biomimetic shell microstructure. The three-dimensional model of the nickel-titanium alloy part is then established on the three-dimensional model of the biomimetic shell microstructure. Finally, three three-dimensional models of the titanium alloy-nickel-titanium alloy heteromaterial are obtained and the STL file is output. The stretching height is designed to be 30μm, which allows the stretched titanium alloy and nickel-titanium alloy in S1 and S2 to interlock.
[0024] S3. Import the STL files completed in S2 into Materialise Magics software in sequence. Design the corresponding process parameters and plan the laser path for the three-dimensional models of the titanium alloy parts, the biomimetic shell microstructure, and the nickel-titanium alloy parts respectively, and obtain three processing files: titanium alloy, biomimetic shell microstructure, and nickel-titanium alloy. S4. Import the three processing files obtained in S3 into the laser powder bed system, read the titanium alloy processing file, start the laser, and melt and solidify the laid titanium alloy powder layer by layer through the laser to form the titanium alloy part. The process parameters are as follows: laser power is 175W, laser scanning speed is 950mm / s, scanning spacing is 50μm, and powder thickness is 30μm. S5. After the titanium alloy part is printed, pause printing. Using a vacuum glove and a brush inside the machine, clean the titanium alloy powder in the forming cylinder and on the formed titanium alloy part into the recycling cylinder. Then, spread nickel-titanium alloy powder. Then, read the biomimetic shell microstructure processing file and melt and solidify part of the nickel-titanium alloy powder layer by layer with a laser to form the biomimetic shell microstructure part. The process parameters are as follows: laser power is 105W, laser scanning speed is 1400mm / s, scanning interval is 50μm, and powder thickness is 30μm. S6. After the biomimetic seashell microstructure is printed, pause printing, read the nickel-titanium alloy processing file, and melt and solidify the remaining nickel-titanium alloy powder layer by layer by laser to form the nickel-titanium alloy part. The process parameters are as follows: laser power is 105W, laser scanning speed is 1400mm / s, scanning interval is 50μm, and powder thickness is 30μm.
[0025] S7. After the target part has been formed, allow it to cool naturally. Use an electrical discharge wire cutting device to cut the part from the substrate, and ultrasonically clean the surface stains in machine oil. Finally, obtain a dense, defect-free titanium alloy-nickel titanium alloy heterostructure component with good interface bonding. Its interface and structure are as follows: Figure 1 and Figure 5 As shown.
[0026] The titanium alloy-nickel-titanium alloy heterostructure was ground and polished according to standard metallographic preparation methods. The interface of the titanium alloy-nickel-titanium alloy heterostructure was observed under an optical microscope. Figure 9 As shown. From Figure 9 It can be observed that the titanium alloy-nickel titanium alloy heterogeneous material interface has good bonding and no defects such as cracks or pores. The use of the interface biomimetic shell layer heterogeneous material microstructure can disperse the thermal stress at the interface during the forming process, thereby reducing the residual stress at the interface and avoiding defects such as cracks and pores at the interface, ultimately achieving the goal of improving the comprehensive mechanical properties. Comparative Example 1
[0027] Comparative Example 1 follows essentially the same steps as Example 1, except that the biomimetic shell-layer heterogeneous material microstructure method is not used at the interface. Instead, the nickel-titanium alloy part is formed directly after the titanium alloy part is formed. The interface and structure are as follows: Figure 2 and Figure 6 As shown.
[0028] The titanium alloy-nickel-titanium alloy heterostructure was ground and polished according to standard metallographic preparation methods. The interface of the titanium alloy-nickel-titanium alloy heterostructure was observed under an optical microscope. Figure 10 As shown.
[0029] observe Figure 10 and with Example 1 Figure 9 The comparison reveals that when a biomimetic shell-like heterogeneous material microstructure is not employed, directly forming a nickel-titanium alloy on a titanium alloy matrix leads to significant interfacial thermal stress concentration. Specifically, this manifests as significant thermal mismatch stress in the sample interface region, accompanied by severe cracking susceptibility, ultimately resulting in continuous, penetrating macroscopic cracks parallel to the interface direction. Comparative Example 2
[0030] Comparative Example 2 is basically the same as Example 1, except that it uses a microstructure arranged in an equilateral triangular array at the interface. The interface and structure are as follows: Figure 3 and Figure 7 As shown.
[0031] The titanium alloy-nickel-titanium alloy heterostructure was ground and polished according to standard metallographic preparation methods. The interface of the titanium alloy-nickel-titanium alloy heterostructure was observed under an optical microscope. Figure 11 As shown.
[0032] observe Figure 11 and with Example 1 Figure 9The comparison shows that using a microstructure with an equilateral triangular array at the titanium alloy-nickel titanium alloy interface partially releases the interfacial thermal stress during the forming process. Compared to using a biomimetic shell-like heterogeneous material microstructure at the interface, this method reduces the size of interfacial cracks, but still fails to completely suppress crack formation. Comparative Example 3
[0033] Comparative Example 3 is basically the same as Example 1, except that it uses a square array of microstructures at the interface, and its interface and structure are as follows: Figure 4 and Figure 8 As shown.
[0034] The titanium alloy-nickel-titanium alloy heterostructure was ground and polished according to standard metallographic preparation methods. The interface of the titanium alloy-nickel-titanium alloy heterostructure was observed under an optical microscope. Figure 12 As shown.
[0035] observe Figure 12 and with Example 1 Figure 9 The comparison shows that using a square array of microstructures at the titanium alloy-nickel titanium alloy interface further alleviates the thermal stress at the sample interface, and consequently reduces the cracks at the interface, but still fails to completely suppress crack formation.
[0036] In summary, this invention employs a biomimetic shell-like microstructure of heterogeneous materials to disperse interfacial thermal stress at the titanium alloy-nickel-titanium alloy interface. This addresses the interfacial problems caused by excessive residual stress at the titanium alloy-nickel-titanium alloy interface during laser powder fusion, which leads to cracks and defects in the brittle intermetallic compound. Ultimately, this results in a titanium alloy-nickel-titanium alloy heterostructure with good metallurgical bonding, no cracks, and high bonding strength.
[0037] Compared to conventional triangular and square microstructures, this invention utilizes a biomimetic shell microstructure to improve the interfacial formability of heterogeneous materials formed by laser additive manufacturing. During laser melting, the sharp corners of triangular microstructures are prone to forming pores due to insufficient melt flow; the right-angled areas of square microstructures are prone to forming pore defects due to incomplete powder melting or spheroidization effects; while the periodicity of the biomimetic shell microstructure units allows for a more uniform distribution of laser energy, thereby improving the formation of interfacial defects.
[0038] Compared to conventional triangular and square microstructures, this invention employs a biomimetic shell microstructure to further alleviate interfacial thermal stress in heterogeneous materials formed by laser additive manufacturing. The radius of curvature at the vertices of triangular microstructures tends to zero, leading to localized stress singularities; square microstructures exhibit both shear stress concentration and normal stress concentration at their right angles, forming combined critical points; while the isotropic nature of the units in the biomimetic shell microstructure results in a low stress concentration factor when loaded in any in-plane direction. Furthermore, this unit can effectively force multiple crack deflections. Therefore, this biomimetic shell microstructure can effectively disperse thermal stress at the interface of heterogeneous materials.
[0039] Compared to traditional welding, riveting, and tenoning processes for joining dissimilar materials, this invention utilizes laser powder bed fusion technology to integrally form dissimilar material components. It fully leverages the high degree of freedom inherent in laser additive manufacturing, reducing the number of connecting parts required for structural components, minimizing processing steps, and shortening production cycles. This achieves lightweight, integral forming of structural components. The formed structural components are suitable for the production of complex, dimensionally precise, and small-batch applications in aerospace, medical equipment, national military, and industrial automotive fields.
Claims
1. A method for preparing a titanium alloy-nickel titanium alloy heterostructure material using a biomimetic seashell microstructure interface, characterized in that, The steps include the following: S1. Establish a model of the titanium alloy base part. Take several seed points in the top surface area of the part. Connect two adjacent seed points and draw a perpendicular bisector on the connection line. The intersection of the perpendicular bisectors is used as the vertex of the biomimetic shell microstructure. The intersection of the perpendicular bisector and the boundary of the top surface area of the part is also used as the vertex of the biomimetic shell microstructure. Connect all vertices along the direction of the perpendicular bisector to obtain several closed graphic units. The overall pattern formed by all the closed graphic units is used as the interface pattern of the biomimetic shell microstructure. Extrude the area where some of the closed graphic units are located to obtain a complete three-dimensional model of the titanium alloy part. S2. Stretch the area containing the other closed graphic units that were not stretched in S1 to the same height to obtain a three-dimensional model of the biomimetic shell microstructure. On the three-dimensional model of the biomimetic shell microstructure, build a three-dimensional model of the nickel-titanium alloy part. S3. Laser path planning was performed on the 3D models of titanium alloy parts, biomimetic shell microstructures, and nickel-titanium alloy parts to obtain three processing files: titanium alloy, biomimetic shell microstructure, and nickel-titanium alloy. S4. Import the three processing files into the laser powder bed system, read the titanium alloy processing file, and melt and solidify the laid titanium alloy powder layer by layer with laser to form a titanium alloy part. S5. Clean the titanium alloy powder into the recovery cylinder of the laser powder bed, then spread nickel-titanium alloy powder, read the biomimetic shell microstructure processing file, and melt and solidify part of the nickel-titanium alloy powder layer by layer by laser to form the biomimetic shell microstructure part. S6. Read the nickel-titanium alloy processing file, and use laser to melt and solidify the remaining nickel-titanium alloy powder layer by layer to form a nickel-titanium alloy part, thereby obtaining the titanium alloy-nickel-titanium alloy heteromaterial.
2. The method for preparing a titanium alloy-nickel titanium alloy heterostructure material using a biomimetic seashell microstructure interface according to claim 1, characterized in that, In S1, the number of seed points is 28, and the seed point distribution is selected as a regular distribution.
3. The method for preparing a titanium alloy-nickel titanium alloy heterostructure material using a biomimetic seashell microstructure interface according to claim 1, characterized in that, In S1, the distribution positions of some closed graphic units are randomly distributed.
4. The method for preparing a titanium alloy-nickel titanium alloy heterostructure material using a biomimetic seashell microstructure interface according to claim 1, characterized in that, In S1, the total area occupied by the partially enclosed graphic units is half the area of the top surface of the part.
5. The method for preparing a titanium alloy-nickel titanium alloy heterostructure material with a biomimetic seashell microstructure interface according to claim 1, characterized in that, In S1 and S2, the stretching height is 30 μm.
6. The method for preparing a titanium alloy-nickel titanium alloy heterostructure material with a biomimetic seashell microstructure interface according to claim 1, characterized in that, In step S4, the laser power used to melt and solidify titanium alloy powder in the laser powder bed is 175W, the laser scanning speed is 950mm / s, the scanning interval is 50μm, and the powder thickness is 30μm.
7. The method for preparing a titanium alloy-nickel titanium alloy heterostructure material with a biomimetic seashell microstructure interface according to claim 1, characterized in that, In S5 and S6, the laser power used to melt and solidify the nickel-titanium alloy powder in the laser powder bed is 105W, the laser scanning speed is 1400mm / s, the scanning spacing is 50μm, and the powder thickness is 30μm.
8. A titanium alloy-nickel titanium alloy heterostructure material with a biomimetic shell microstructure interface, prepared by the method according to any one of claims 1 to 7.