A method for improving the bonding strength of cold spray additive manufacturing

Abstract

The present application relates to a method for improving the bonding strength of cold spray additive manufacturing, which includes: obliquely cutting the additive interface of the cavity part to obtain a cutting opening; cold spraying elemental powder of the additive raw material into the cutting opening to form an internal additive component that propping against the inner wall of the top of the cavity part; cold spraying elemental powder of the additive raw material on the outer surface of the cavity part to form an external additive component; performing heat treatment on the internal additive component and the external additive component to alloy the elemental powder of the additive raw material. By forming a part of the additive component inside the part, an additional interface is added inside the part, resulting in a higher bonding strength between the additive component and the part, reducing the problem of high brittleness in direct cold spray additive manufacturing on the surface. Then, cold spraying is carried out on the outside, and the formed external additive component and the internal additive component are heat-treated together to finally obtain a high-strength additive component coating, which has stronger toughness and bonding strength with the part.

Description

Technical Field

[0001] This application relates to the technical field of cold spray additive manufacturing, and particularly to a method for improving the bonding strength of cold spray additive manufacturing. Background Art

[0002] The existing additive manufacturing technologies at home and abroad mainly focus on metal material additive manufacturing technologies, which are mainly applied in the fields of aerospace, biomedicine, transportation, clothing and jewelry, etc. With the increasing application scope of additive manufacturing technologies, people's requirements for additive manufacturing technologies have gradually increased. The previous use of single-element metals for additive manufacturing can no longer meet the process requirements. Nowadays, people have developed alloys formed by a variety of mixed metals for additive manufacturing.

[0003] For TiAl alloy materials, Ti2AlNb materials have been applied to additive manufacturing technologies. However, in the process of additive manufacturing of structural parts using Ti2AlNb, a direct additive manufacturing method is usually adopted. However, when directly adding materials to parts, there is a problem of fragile additive interface structure. Summary of the Invention

[0004] The embodiments of this application provide a method for improving the bonding strength of cold spray additive manufacturing to solve the problem of fragile additive interface structure existing in directly adding materials to parts in related technologies.

[0005] The embodiments of this application provide a method for improving the bonding strength of cold spray additive manufacturing, which includes:

[0006] Obliquely cutting the additive interface of the cavity part (1) to obtain a cutting opening (2);

[0007] Cold spraying elemental powder of additive raw materials into the cutting opening (2) to form an internal additive component (3) that propping against the inner wall of the top of the cavity part (1);

[0008] Cold spraying elemental powder of additive raw materials on the outer surface of the cavity part (1) to form an external additive component (4);

[0009] Performing heat treatment on the internal additive component (3) and the external additive component (4) to alloy the elemental powder of the additive raw materials.

[0010] In some embodiments, performing heat treatment on the internal additive component (3) and the external additive component (4) to alloy the elemental powder of the additive raw materials includes the following steps:

[0011] Performing a first heat treatment on the internal additive component (3) and the external additive component (4) to partially alloy the elemental powder of the additive raw materials to obtain an intermediate;

[0012] Performing machining on the intermediate;

[0013] The intermediate product after machining is subjected to a second heat treatment to fully alloy the elemental powders of the additive raw materials.

[0014] In some embodiments, the temperature of the first heat treatment is 300°C to 500°C, and the time is 1 h to 2 h.

[0015] In some embodiments, the temperature of the second heat treatment is 500°C to 600°C, and the time is 1 h to 2 h.

[0016] In some embodiments, after the first heat treatment, the mass fraction of alloyed elemental powders of the additive raw materials is 50% to 80%.

[0017] In some embodiments, the elemental powders of the additive raw materials include Ti powder, Al powder, and Si powder, and the alloying product of the elemental powders of the additive raw materials is Ti2AlNb alloy.

[0018] In some embodiments, the oblique cutting angle β of the cutting opening (2) is 43° to 47°;

[0019] and / or, the size range of the oblique cutting is 3 mm to 5 mm.

[0020] In some embodiments, the inclination angle γ of the internal additive member (3) is 20° to 25°;

[0021] and / or, the thickness h of the internal additive member (3) is 3 mm to 5 mm.

[0022] In some embodiments, before cold spraying the elemental powders of the additive raw materials into the cutting opening (2), the following steps are further included:

[0023] The additive interface and the cutting opening (2) are surface-treated to reach a preset roughness.

[0024] In some embodiments, the preset roughness Ra is 3.2 to 6.3.

[0025] The beneficial effects brought by the technical solution provided in this application include:

[0026] The embodiment of the present application provides a method for improving the bonding strength of cold spray additive manufacturing. The present application combines the cold spray additive manufacturing technology with interface design and is used for workpieces that require additive manufacturing of parts. A part of the additive component is formed inside the part, so that an interface is also added inside the part, which can effectively enhance the structure of the additive component, endow it with a certain torsional resistance, make the bonding strength between the additive component and the part higher, and reduce the problem of high brittleness in direct surface cold spray additive manufacturing. Then, the powder after mixing elemental raw materials for additive manufacturing is cold sprayed externally, and the formed external additive component and the internal additive component are heat treated together to finally obtain a high-strength additive component coating, which has stronger toughness and bonding strength with the part.

[0027] The present application uses elemental powders to make ratios according to the molecular formula for cold spray additive manufacturing, and then uses heat treatment to achieve a balanced effect. The additive component obtained by this method has both a certain strength and a certain plasticity, which is convenient for machining the additive component.

[0028] This type of additive manufacturing technology is used for additive manufacturing of large-sized structural parts. Coupled with the cold spray additive manufacturing technology, it shortens the construction period of direct casting and reduces complexity. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for description in the embodiments. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0030] Figure 1 It is a flowchart of the method for improving the bonding strength of cold spray additive manufacturing provided by the embodiment of the present application;

[0031] Figure 2 It is a schematic diagram of a cavity part provided by the embodiment of the present application

[0032] Figure 3 It is a schematic diagram of the cavity part after being obliquely cut provided by the embodiment of the present application;

[0033] Figure 4 It is a schematic diagram of the cavity part after cold spraying provided by the embodiment of the present application;

[0034] Figure 5 For Figure 4 It is a schematic diagram after passing through the first heat treatment, machining, and the second heat treatment in sequence.

[0035] In the figure: 1. Cavity part; 2. Cutting edge; 3. Internal additive component; 4. External additive component. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0036] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the following will clearly and completely describe the technical solutions in the embodiments of this application with reference to the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are some, but not all, of the embodiments of this application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this application without creative efforts fall within the scope of protection of this application.

[0037] See Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, the embodiments of this application provide a method for improving the bonding strength of cold spray additive manufacturing, which includes the following steps:

[0038] 101: Since directly performing additive manufacturing on the cavity part 1 will result in a problem of high brittleness between the additive component and the cavity part, therefore, first, the additive interface of the cavity part 1 is obliquely cut to obtain a cut 2.

[0039] See Figure 2 As shown, taking the cavity part 1 as a square as an example, the two corner parts of the cavity part 1 can be obliquely cut to form the cut 2.

[0040] Among them, the cutting range of the cut 2 can be determined according to the size of the cavity part 1. For example, as an example, the size range of the oblique cut is 3 mm to 5 mm.

[0041] Furthermore, the oblique cut angle β of the cut 2 can be determined according to the actual situation. For example, the oblique cut angle β of the cut 2 can be 43° to 47°, and more preferably, the oblique cut angle β of the cut 2 is 45°.

[0042] To improve the activity of the additive interface of the cavity part 1 and improve the bonding strength between the additive component and the cavity part, preferably, after the oblique cut, the following steps are further included: surface treatment of the additive interface and the cut 2 to reach a preset roughness. Among them, the surface treatment includes grinding and polishing the additive interface and the cut.

[0043] The size of the above-mentioned preset roughness can be determined according to actual needs. For example, as an example, the preset roughness Ra is 3.2 to 6.3.

[0044] 102: Cold spray the elemental powder of the additive raw material into the cut 2 to form an internal additive component 3 that propping against the inner wall of the top of the cavity part 1.

[0045] In this step, the elemental powder of the additive raw material is proportioned by molecular formula, and then the inside of the cut 2 is cold-sprayed using cold spraying technology.

[0046] The above-mentioned elemental powder of the additive raw material can adopt the raw material powder commonly used in cold spraying.

[0047] For example, as an example, the elemental powder of the additive raw material includes Ti powder, Al powder and Si powder, and the alloying product of the elemental powder of the additive raw material is Ti2AlNb alloy.

[0048] The top of the above-mentioned internal additive component 3 abuts against the inner wall of the top of the cavity part 1, so that the reinforcing component has a certain torsional resistance, thereby improving the strength of the additive component.

[0049] When cold-spraying the inside of the cut 2, it can be sprayed obliquely so that the internal additive component 3 is arranged obliquely. The inclination angle γ and thickness h of the internal additive component 3 can be determined according to the actual situation. For example, as an example, the inclination angle γ of the internal additive component 3 is 20° - 25°, and the thickness h of the internal additive component 3 is 3mm - 5mm.

[0050] The bottom of the above-mentioned internal additive component 3 can abut against the side wall inside the cavity part 1, or can be integrated with the subsequent external additive component 4.

[0051] 103: Cold-spray the elemental powder of the additive raw material on the outer surface of the cavity part 1 to form an external additive component 4;

[0052] During cold spraying in step 103, the thickness of the sprayed interface should exceed the outer boundary of the cavity part 1 by 1 - 2mm. Doing so is to ensure that the sprayed material can be fully covered and form a good bond with the cavity part 1. This can ensure that the part after additive manufacturing has better strength and durability, and at the same time can avoid problems such as interface failure.

[0053] 104: Heat-treat the internal additive component 3 and the external additive component 4 to alloy the elemental powder of the additive raw material.

[0054] In step 104, heat-treating the internal additive component 3 and the external additive component 4 to alloy the elemental powder of the additive raw material includes the following steps:

[0055] 201: Conduct the first heat treatment on the internal additive component 3 and the external additive component 4 to partially alloy the elemental powder of the additive raw material to obtain an intermediate;

[0056] In step 201, the simple substances inside the additive component will react as the heat treatment temperature increases to form an alloy, such as Ti2AlNb. After heating to a certain extent, it is ensured that the simple substances inside do not completely react, that is, part of them remains as simple substances and part forms an alloy, making the intermediate in a balanced state including a simple substance phase and an alloy phase. At this time, the intermediate is like a mixed-phase component, which increases the strength and toughness of the material. The advantage of doing this is that the additive component has a certain strength, better machining performance, reduced machining difficulty, and improved additive quality.

[0057] The temperature of the first heat treatment is 300°C to 500°C, and the time is 1h to 2h. If the heat treatment temperature and time are too low, it may have a greater impact on the mechanical properties and corrosion resistance of the additive component, which is not conducive to improving the machining performance. If the heat treatment temperature and time are too high, it will have a greater impact on the mechanical properties of the additive component, which is also not conducive to improving the machining performance.

[0058] After the first heat treatment, the mass fraction of alloying of the simple substance powder of the additive raw material is 50% to 80%, that is, after the first heat treatment, the mass ratio of the simple substance phase is 20% to 50%, and the mass ratio of the alloy phase is 50% to 80%.

[0059] Too low a proportion of the alloy phase may lead to a decrease in the hardness and wear resistance of the material, and too low a proportion of the simple substance phase may lead to a decrease in the plasticity and toughness of the material. Too high a proportion of the alloy phase may lead to problems such as too high a melting point of the alloy and increased mixing difficulty during the preparation process, and too high a proportion of the simple substance phase may lead to problems such as easy peeling and insufficient toughness of the additive component after spraying. By controlling the ratio of the alloy phase to the simple substance phase, it is ensured that the degree of alloying of the mixed-phase component reaches an ideal state, thereby improving its machining performance.

[0060] 202: Machine the intermediate to meet relevant requirements.

[0061] 203: Perform a second heat treatment on the intermediate after machining to completely alloy the simple substance powder of the additive raw material.

[0062] In step 203, heat treatment is performed again to make the simple substances originally present inside react fully and finally be completely alloyed, turning all the simple substance phases in the mixed-phase component including the simple substance phase and the alloy phase into alloy phases, so that the additive has excellent wear resistance and strength.

[0063] The temperature of the second heat treatment is 500°C to 600°C, and the time is 1h to 2h.

[0064] If the heat treatment temperature is too low and the treatment time is too short, the single-phase cannot be completely transformed into the alloy phase, resulting in poor additive wear resistance and strength. If the heat treatment temperature is too high and the treatment time is too long, the alloying elements in the mixed-phase component will dissolve with the elements of the cavity part, leading to grain growth, coarsening of the structure, and even the formation of a liquid phase, thus causing sintering. This will result in a decrease in mechanical properties such as the hardness, tensile strength, and elongation of the additive. Excessive heat treatment temperature and time will also cause changes in the chemical composition of the mixed-phase component. Too much Al element in the Ti2AlNb alloy dissolves into the Ti matrix, which will cause changes in the crystal structures of the α-phase and β-phase, thereby reducing the mechanical properties such as the strength and plasticity of the additive.

[0065] The embodiment of the present application provides a method for improving the bonding strength of cold-sprayed additive. The present application combines the cold-sprayed additive technology with interface design and is used for workpieces that require additive use on parts. A part of the additive component is formed inside the part, adding an interface inside the part, which can effectively enhance the structure of the additive component, endowing it with a certain torsional resistance, making the bonding strength between the additive component and the part higher, reducing the large brittleness problem of directly performing cold-sprayed additive on the surface. Then, the powder after mixing the elemental raw materials for additive is cold-sprayed externally, and the formed external additive component and the internal additive component are heat-treated together to finally obtain a high-strength additive component coating, which has stronger toughness and bonding strength with the part.

[0066] The present application uses elemental powders to be proportioned according to the molecular formula for cold-sprayed additive, and then uses heat treatment to achieve a balanced effect. The additive component obtained by this method has both a certain strength and a certain plasticity, facilitating the machining treatment of the additive component.

[0067] This type of additive technology is used for additive of large-sized structural parts. Coupled with the cold-sprayed additive technology, it shortens the construction period of direct casting and reduces complexity.

[0068] The following details the present application through several examples and comparative examples.

[0069] Example 1

[0070] A method for improving the bonding strength of cold-sprayed additive, which includes the following steps:

[0071] 301: Obliquely cut the additive interface of the cavity part 1 to obtain a cutting edge 2, and the obliquely cutting angle β of the cutting edge 2 is 45°.

[0072] 302: Cold spray Ti powder, Al powder and Si powder into the cutting opening 2 to form an internal additive component 3 that props against the inner wall of the top of the cavity part 1. The inclination angle γ of the internal additive component 3 is 20°, and the thickness h of the internal additive component 3 is 4 mm. The Ti powder, Al powder and Nb powder are proportioned according to a molar ratio of 2:1:1.

[0073] 303: Cold spray Ti powder, Al powder and Si powder on the outer surface of the cavity part 1 to form an external additive component 4. The Ti powder, Al powder and Nb powder are proportioned according to a molar ratio of 2:1:1.

[0074] 304: Conduct the first heat treatment on the internal additive component 3 and the external additive component 4 to partially alloy the Ti powder, Al powder and Si powder to obtain an intermediate.

[0075] The temperature of the first heat treatment is 400 °C, and the time is 1 h.

[0076] 305: Machine the intermediate to meet the relevant requirements.

[0077] 306: Conduct the second heat treatment on the intermediate after machining to fully alloy the elemental powder of the additive raw material.

[0078] The temperature of the second heat treatment is 550 °C, and the time is 1 h.

[0079] Example 2

[0080] The difference between Example 2 and Example 1 is that the time of the first heat treatment is 0.5 h.

[0081] Example 3

[0082] The difference between Example 3 and Example 1 is that the time of the first heat treatment is 2.5 h.

[0083] Example 4

[0084] The difference between Example 4 and Example 1 is that the time of the second heat treatment is 0.5 h.

[0085] Example 5

[0086] The difference between Example 5 and Example 1 is that the time of the second heat treatment is 2.5 h.

[0087] Comparative Example 1

[0088] In Comparative Example 1, additive manufacturing is directly carried out on the surface of the cavity part 1. Among them, the heat treatment temperature is 500 °C, and the time is 2 h, so that all the single-phase components are converted into alloy phases.

[0089] Comparative Example 2

[0090] The difference between Comparative Example 2 and Example 1 is that the Ti powder, Al powder, and Nb powder are proportioned according to a molar ratio of 1:1:1.

[0091] Performance test

[0092] The following performance tests were carried out on the additive products manufactured in Examples 1-5 and Comparative Examples 1-2.

[0093] (1) Plasticity:

[0094] The plasticity test was carried out in accordance with GB / T228.1-2021 "Metallic materials - Tensile testing - Part 1: Method of test at room temperature".

[0095] (2) Abrasion resistance:

[0096] The abrasion resistance test was carried out in accordance with GB / T12444-2006 "Test method for wear of metallic materials - Ring-on-block sliding wear test".

[0097] The test results are shown in Table 1.

[0098] Table 1

[0099]

[0100]

[0101] From the plasticity data and abrasion resistance data in the above Table 1, compared with the results of Comparative Example 1 and Comparative Example 2, by using the method of the present application, the plasticity and abrasion resistance of the additive can be improved. Among them, the yield strength can reach 800 MPa, far higher than 700 MPa of the comparative example, the elongation rate reaches 13%, far higher than 6% of the comparative example, and the wear amount reaches 0.0001 g, far lower than 0.0006 g of the comparative example. It can be seen that the method of the present application uses the method of heating the elemental powders of Ti, Al, and Nb to become Ti2AlNb, proportioned according to the molecular formula, and performing primary heat treatment after cold spraying, so that the powder undergoes an incomplete chemical reaction, and part of the elemental phase is transformed into the Ti2AlNb alloy phase. During the heating process, the internal atoms will diffuse, and the structure formed by Ti2AlNb and the elemental substances of Ti, Al, and Nb in the coating reaches an equilibrium state, increasing the strength and toughness of the material. On this basis, mechanical processing has higher processing performance. Finally, secondary heat treatment is carried out to convert all the remaining elemental phases into alloy phases, so as to obtain a Ti2AlNb coating with excellent abrasion resistance. The method of the present application has stronger plasticity than directly using Ti2AlNb material as the coating, further improving the performance of the workpiece.

[0102] From Examples 1, 2, and 3, compared with Example 1 where the first heat treatment only took 1 hour, Example 2 and Example 3 took 0.5 hour and 2.5 hours respectively. Judging from the performance data, their performance is worse than that of Example 1, but still better than that of Comparative Example 1 and Comparative Example 2. It can be seen that when performing the first heat treatment, if the heat treatment temperature is too low, the treatment time is too short, or the heat treatment temperature is too high and the treatment time is too long, it will have a greater impact on the mechanical properties and corrosion resistance of the additive parts, which is not conducive to improving the processing performance.

[0103] Combined with Examples 1, 4, and 5, compared with Example 1 where the second heat treatment only took 1 hour, Example 2 and Example 3 took 0.5 hour and 2.5 hours respectively. Judging from the performance data, their performance is worse than that of Example 1, but still better than that of Comparative Example 1 and Comparative Example 2. It can be seen that when performing the second heat treatment, if the heat treatment temperature is too low and the treatment time is too short, the single-phase cannot be completely transformed into the alloy phase, resulting in poor wear resistance and strength of the coating; if the heat treatment temperature is too high and the treatment time is too long, the alloying elements in the mixed coating will dissolve with the matrix metal elements, resulting in grain growth and coarser structure, and even liquid phase will be generated, causing sintering phenomenon. This will lead to a decrease in mechanical properties such as the hardness, tensile strength, and elongation of the additive. Excessive heat treatment temperature and time will also change the chemical composition in the mixed coating. Too much Al element in the Ti2AlNb alloy dissolves into the Ti matrix, which will cause changes in the crystal structures of the α-phase and β-phase, thus reducing the mechanical properties such as the strength and plasticity of the additive.

[0104] Example 6

[0105] A method for improving the bonding strength of cold-sprayed additive, which comprises the following steps:

[0106] 301: Obliquely cut the additive interface of the cavity part 1 to obtain a cut 2, and the oblique cutting angle β of the cut 2 is 45°.

[0107] 302: Cold-spray Ti powder, Al powder, and Si powder in the cut 2 to form an internal additive member 3 that propping against the inner wall of the top of the cavity part 1. The inclination angle γ of the internal additive member 3 is 20°, and the thickness h of the internal additive member 3 is 4 mm.

[0108] 303: Cold-spray Ti powder, Al powder, and Si powder on the outer surface of the cavity part 1 to form an external additive member 4.

[0109] 304: Perform the first heat treatment on the internal additive member 3 and the external additive member 4 to partially alloy the Ti powder, Al powder, and Si powder to obtain an intermediate.

[0110] The temperature of the first heat treatment is 400 °C and the time is 1 h.

[0111] 305: Machine process the intermediate to meet the relevant requirements.

[0112] 306: Perform a second heat treatment on the intermediate after machining to alloy all the elemental powders of the additive raw material.

[0113] The temperature of the second heat treatment is 550 °C and the time is 1 h.

[0114] Example 7

[0115] The difference between Example 7 and Example 6 is that the inclination angle γ of the internal additive member 3 is 22°.

[0116] Example 8

[0117] The difference between Example 8 and Example 6 is that the inclination angle γ of the internal additive member 3 is 24°.

[0118] Example 9

[0119] The difference between Example 9 and Example 6 is that the inclination angle γ of the internal additive member 3 is 25°.

[0120] Comparative Example 3

[0121] In Comparative Example 3, additive manufacturing is directly carried out on the surface of the cavity part 1.

[0122] Performance test

[0123] Perform the following performance tests on Examples 6 - 9 and Comparative Example 3: Test the additive bonding strength according to the test method for the bonding strength of the target and the backplane in GB / T39163 - 2020.

[0124] The test results are shown in Table 2.

[0125] Table 2

[0126] Example 6 Example 7 Example 8 Example 9 Comparative Example 3 Tilt angle γ 20° 22° 24° 25° - Additive bonding strength 83 MPa 81 MPa 80 MPa 80 MPa 76 MPa

[0127] Judging from the additive bonding strength data in Table 2 above, the additive bonding strengths are all higher than that of Comparative Example 3. By using the method of this application, a cutting opening is made on the part, and a part of the additive is formed inside, so that the reinforcing member has a certain torsional resistance, thereby improving the bonding strength of the additive member.

[0128] In the description of the present application, it should be noted that the orientation or positional relationship indicated by terms such as "upper" and "lower" is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present application. Unless otherwise clearly specified and defined, the terms "mounted", "connected" and "coupled" shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0129] It should be noted that in the present application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the said element.

[0130] The above are only specific embodiments of the present application, enabling those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for improving the bonding strength of cold spray additive manufacturing, characterized in that, It includes: Obliquely cutting the additive interface of the cavity part (1) to obtain a cutting opening (2); Cold spraying elemental powder of additive raw material into the cutting opening (2) to form an internal additive component (3) that propping against the inner wall of the top of the cavity part (1); Cold spraying elemental powder of additive raw material on the outer surface of the cavity part (1) to form an external additive component (4); Performing heat treatment on the internal additive component (3) and the external additive component (4) to alloy the elemental powder of additive raw material, and the product of alloying the elemental powder of additive raw material is Ti2AlNb alloy.

2. The cold spraying additive manufacturing bonding strength improvement method according to claim 1, wherein, Performing heat treatment on the internal additive component (3) and the external additive component (4) to alloy the elemental powder of additive raw material, including the following steps: Performing a first heat treatment on the internal additive component (3) and the external additive component (4) to partially alloy the elemental powder of additive raw material to obtain an intermediate; Performing machining on the intermediate; Performing a second heat treatment on the intermediate after machining to completely alloy the elemental powder of additive raw material.

3. The cold spraying additive manufacturing bonding strength improvement method according to claim 2, characterized in that: The temperature of the first heat treatment is 300°C to 500°C, and the time is 1h to 2h.

4. The cold spraying additive manufacturing bonding strength improvement method according to claim 2, wherein: The temperature of the second heat treatment is 500°C to 600°C, and the time is 1h to 2h.

5. The cold spraying additive bonding strength improvement method according to claim 2, wherein: After the first heat treatment, the mass fraction of alloying of the elemental powder of additive raw material is 50% to 80%.

6. The method for improving the bonding strength of cold spraying additive according to claim 1, wherein: The oblique cutting angle β of the cutting opening (2) is 43° to 47°; And / or, the size range of oblique cutting is 3mm to 5mm.

7. The method for improving the bonding strength of cold spraying additive according to claim 1, wherein: The inclination angle γ of the internal additive component (3) is 20° to 25°; And / or, the thickness h of the internal additive component (3) is 3mm to 5mm.

8. The method for improving the bonding strength of cold spraying additive as claimed in claim 1, wherein Before cold spraying elemental powder of additive raw material into the cutting opening (2), the following steps are further included: Performing surface treatment on the additive interface and the cutting opening (2) to reach a preset roughness.

9. The cold spraying additive bonding strength improvement method according to claim 8, characterized in that: The preset roughness Ra is 3.2 to 6.3.

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