IN718 modified coating and preparation method thereof
Through the Ti and B composite modified IN 718 alloy coating, the problem of insufficient mechanical properties and corrosion resistance of traditional IN 718 alloy at high temperatures is solved, and the application in the fields of aerospace and energy power is achieved.
Patent Information
- Application Number
- CN202510836292.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-21
- Publication Date
- 2025-08-15
AI Technical Summary
The mechanical properties and corrosion resistance of traditional IN 718 alloys at high temperatures are difficult to meet the extreme operating conditions requirements in cutting-edge fields such as aerospace and energy power, especially the addition of Ti will aggravate the oxidation rate and reduce the oxidation resistance of the alloy.
Using Ti and B composite modified IN 718 alloy, a coating was prepared on the steel substrate through a plasma cladding process, the ratio and particle size of Ti and B were adjusted, and the cladding parameters were optimized to form a modified coating.
It improves the mechanical properties and oxidation resistance of the coating at high temperatures, making it more suitable for extreme working conditions and extends its service life.
Smart Images
Figure CN120485767A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of IN 718 coating modification, and in particular to an IN 718 modified coating and a preparation method thereof. Background Art
[0002] Inconel 718 (IN 718) alloy is currently the most widely used nickel-based high-temperature alloy both domestically and internationally. This alloy boasts excellent high-temperature strength, oxidation resistance, and corrosion resistance, and is widely used in a wide range of fields, including aerospace, energy and chemical engineering, and the nuclear industry. However, numerous studies have shown that above 600°C, the alloy's mechanical properties and corrosion resistance decrease significantly with increasing temperature. This impacts the overall service life of the coating and makes it difficult to exceed the upper service temperature limit of IN 718 alloy.
[0003] Furthermore, with the rapid technological advancements in cutting-edge fields like aerospace and energy, next-generation engineering equipment is increasingly operating in extreme environments. This requires critical load-bearing components to operate reliably under increasingly demanding conditions of high temperature and high stress, placing unprecedented demands on the overall performance of materials. Against this backdrop, optimizing the composition, microstructure, and properties of IN 718 alloy to overcome the service life limitations of currently used IN 718 high-temperature alloys is of high research value.
[0004] Currently, researchers at home and abroad have conducted extensive research on the mechanical properties and oxidation resistance of IN 718 superalloy. Cruchley et al. studied the oxidation behavior of RR1000 nickel-based superalloy in the temperature range of 600-900°C for 5000 h, specifically the oxidation kinetics of the alloy and the role of Ti in the oxidation process. Their results showed that Ti, as a high-valent dopant, disrupts the electrical balance of the Cr2O3 oxide layer, forcing the system to generate Cr vacancies to neutralize the charge. However, the generation of Cr vacancies intensifies the diffusion of elements in the oxide layer, thereby increasing the oxidation rate of the system. Shi et al. studied the effect of Ti on the microstructure and properties of GH4710 nickel-based superalloy. The results showed that high concentrations of Ti promote the formation of non-metallic inclusions in the alloy structure and intensify microsegregation and harmful phase precipitation in the alloy, which is theoretically not conducive to improving the mechanical properties of the alloy. Research by Bennett et al. has shown that Ti negatively impacts both the oxidation resistance and mechanical properties of Ni-based superalloys. Ti forms rutile TiO₂ during oxidation. Rutile formation typically occurs at grain boundaries within the oxide scale. Its growth and aggregation can induce stress within the scale, leading to cracking and flaking, thus reducing the alloy's oxidation resistance. Furthermore, the formation and distribution of rutile particles alter the scale's microstructure, making it more porous and thus reducing its protective properties. Furthermore, Ti's high hardness and strength make the alloy susceptible to brittleness during processing, resulting in reduced plasticity. Furthermore, Ti's oxidation and precipitation can create stress concentration areas within the alloy, increasing the risk of crack formation. Especially at high temperatures, Ti's oxidation and precipitation can further exacerbate thermal fatigue and creep, reducing the alloy's service life. Summary of the Invention
[0005] The purpose of the present invention is to propose an IN 718 modified coating and a preparation method thereof, aiming to solve the problem that the mechanical properties and corrosion resistance of traditional IN718 alloy at high temperatures are difficult to apply to cutting-edge fields such as aerospace, energy and power.
[0006] In a first aspect, the present invention provides a method for preparing an IN 718 modified coating, the method comprising: Obtaining a steel base plate and pre-treating the surface of the steel base plate; Commercial IN 718 alloy powder, Ti powder, and B powder are selected and uniformly mixed in a certain proportion to obtain a mixed powder; The pretreated steel substrate plate is placed horizontally on the workbench of the plasma cladding machine, and the mixed powder is put into the powder barrel of the plasma cladding equipment. Under an argon atmosphere, the mixed powder is fed synchronously during the cladding process. After the cladding is completed, the water cooling equipment is immediately turned on to finally obtain the modified IN 718 modified coating.
[0007] Furthermore, the mixed powder includes: 1.5wt% to 2.5wt% Ti powder, 0.01wt% to 0.1wt% B powder, and the rest is commercial IN 718 alloy powder.
[0008] Furthermore, the particle sizes of the commercial IN 718 alloy powder, the Ti powder and the B powder are all 100-200 meshes.
[0009] Furthermore, the purity of the Ti powder and the B powder is greater than 99.9%.
[0010] Furthermore, the commercial IN 718 alloy powder, Ti powder and B powder are selected and uniformly mixed in a certain proportion to obtain a mixed powder; the process comprises: The mixed powder was placed in a vacuum drying oven at 80-120°C and dried for 0.5-1.5h.
[0011] Furthermore, the cladding parameters include: spray gun height 9-10 mm, powder feeding gas flow rate 2-3 L / min, ion gas flow rate 2-3 L / min, shielding gas flow rate 2-3 L / min, and cladding current 110A-120A.
[0012] Furthermore, the step of obtaining a steel base plate and pre-treating the surface of the steel base plate comprises: The steel substrate plate is polished smooth, and then its surface is cleaned with alcohol. The cleaned steel substrate plate is then placed in a vacuum drying oven at 80-120°C and dried for 10-30 minutes.
[0013] In a second aspect, the present invention provides an IN 718 modified coating prepared according to the above-mentioned method for preparing the IN 718 modified coating.
[0014] Compared with the prior art, the present invention has the following advantages: By designing an IN 718 alloy modified with Ti and B, and establishing a complete set of plasma cladding process parameters, the controllable preparation of high-quality IN 718 coatings was achieved. The resulting IN 718 modified coating has excellent mechanical properties and oxidation resistance at high temperatures, and can be better applied to extreme working conditions in aerospace, energy and power and other fields. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The accompanying drawings, which constitute part of the present invention, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings: Figure 1 (a) is a schematic diagram of the structure of the plasma cladding water cooling device. Figure 1 (b) is a schematic diagram of the structure inside the water-cooling plate; Figure 2 (a) Figure 2 (b) Figure 2 (c) Macroscopic images of the coatings prepared in Comparative Example 2, Comparative Example 1, and Example 1, respectively; Figure 3 (a) Figure 3 (b) Figure 3 (c) Metallographic images of the coatings prepared in Comparative Example 2, Example 1, and Comparative Example 1, respectively; Figure 4 XRD patterns of the coatings prepared in Comparative Example 2, Example 1, and Comparative Example 1; Figure 5 The oxidation weight gain curves of the coatings prepared in Comparative Example 2, Example 1, and Comparative Example 1 at 1000°C are shown; Figure 6 (a) Figure 6 (b) Figure 6 (c) (100), (110) and (111) surface models of the γ phase, respectively; Figure 6 (d) Figure 6 (e) Figure 6 (f) Schematic diagram of the adsorption sites of O on the (100), (110) and (111) surfaces of the γ phase; Figure 7 (a) Figure 7 (b) Tensile curves of the coatings prepared in Example 1 and Comparative Example 2 at room temperature and 600°C, respectively; Figure 8 (a) Figure 8 (b) Compression curves of the coatings prepared in Example 1 and Comparative Example 2 at room temperature and 600°C, respectively. DETAILED DESCRIPTION
[0016] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments. It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other.
[0017] The following detailed description is an exemplary description and is intended to provide further detailed description of the present invention. Unless otherwise indicated, all technical terms used in the present invention have the same meaning as those generally understood by those skilled in the art to which the present invention belongs. The terms used in the present invention are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention.
[0018] Example 1 Obtain a steel substrate, polish the steel substrate until smooth, then clean its surface with alcohol, and then place the cleaned steel substrate in a vacuum drying oven at 100°C for 20 minutes; Commercial IN 718 alloy powder, Ti powder, and B powder were selected. The particle size of the commercial IN 718 alloy powder, Ti powder, and B powder were all 150 mesh. The purity of Ti powder and B powder was greater than 99.9%. They were mixed in a mass ratio of 2wt% Ti powder, 0.05wt% B powder, and the rest was commercial IN718 alloy powder to obtain a mixed powder. The mixed powder was placed in a vacuum drying oven at 100°C for 1 hour. The dried steel substrate plate was placed horizontally on the workbench of the plasma cladding machine, and the mixed powder was placed in the powder barrel of the plasma cladding equipment. The cladding parameters were set as follows: spray gun height 9.5 mm, powder feeding gas flow rate 2.5 L / min, ion gas flow rate 2.5 L / min, shielding gas flow rate 2.5 L / min, and cladding current 115 A. Under argon atmosphere, the mixed powder was fed synchronously during the cladding process. After the cladding was completed, the water cooling equipment was immediately turned on to finally obtain the modified IN 718 modified coating.
[0019] Comparative Example 1 Obtain a steel substrate, polish the steel substrate until smooth, then clean its surface with alcohol, and then place the cleaned steel substrate in a vacuum drying oven at 100°C for 20 minutes; Commercial IN 718 alloy powder, Ti powder, and B powder were selected. The particle size of the commercial IN 718 alloy powder, Ti powder, and B powder were all 150 mesh. The purity of Ti powder and B powder was greater than 99.9%. They were mixed in a mass ratio of 2wt% Ti powder, 1wt% B powder, and the rest was commercial IN 718 alloy powder to obtain a mixed powder. The mixed powder was placed in a vacuum drying oven at 100°C for 1 hour. The dried steel substrate plate was placed horizontally on the workbench of the plasma cladding machine, and the mixed powder was placed in the powder barrel of the plasma cladding equipment. The cladding parameters were set as follows: spray gun height 9.5 mm, powder feeding gas flow rate 2.5 L / min, ion gas flow rate 2.5 L / min, shielding gas flow rate 2.5 L / min, and cladding current 115 A. Under argon atmosphere, the mixed powder was fed synchronously during the cladding process. After the cladding was completed, the water cooling equipment was immediately turned on to finally obtain the modified IN 718 modified coating.
[0020] Comparative Example 2 Obtain a steel substrate, polish the steel substrate until smooth, then clean its surface with alcohol, and then place the cleaned steel substrate in a vacuum drying oven at 100°C for 20 minutes; Commercial IN 718 alloy powder was selected. The particle size of the commercial IN 718 alloy powder was 150 mesh. The commercial IN 718 alloy powder was placed in a vacuum drying oven at 100°C for 1 hour. The dried steel substrate was placed horizontally on the workbench of the plasma cladding machine. Commercial IN 718 alloy powder was placed in the powder barrel of the plasma cladding equipment. The cladding parameters were set as follows: spray gun height 9.5 mm, powder feed gas flow rate 2.5 L / min, ion gas flow rate 2.5 L / min, shielding gas flow rate 2.5 L / min, and cladding current 115 A. Under argon atmosphere, mixed powder was fed synchronously during the cladding process. After the cladding was completed, the water cooling equipment was immediately turned on to finally obtain the IN 718 coating.
[0021] For any embodiment and any comparative example, the plasma cladding machine used is manufactured by Shanghai Duomu Industrial Co., Ltd., and the model number is DML-VO3AD; the commercial IN 718 alloy powder, Ti powder, and B powder are purchased from the market.
[0022] Figure 2 (a) Figure 2 (b) Figure 2 (c) are macroscopic images of the coatings prepared in Comparative Example 2, Comparative Example 1, and Example 1, respectively. Figure 2 (ac) It can be seen that the surface quality of the three coatings is high, and there are no obvious macroscopic cladding defects such as cracks and holes. It can be seen that the existing process parameters are reasonable to a certain extent.
[0023] Depend on Figure 3 (ac) It can be seen that there are almost no cladding defects such as pores or cracks in the microstructures of the three coatings, indicating that the cladding parameters of the IN 718 coating obtained for the Q235 steel surface in the present invention are relatively reasonable. On the other hand, this also eliminates the influence of cladding defects such as pores or cracks on the mechanical properties and oxidation resistance of the coating. In addition, Figure 3(ac) It can also be found that the metallographic structure of the IN 718 coating prepared in Comparative Example 2 is coarse columnar crystals, while for the coatings prepared in Example 1 and Comparative Example 1, the doping of Ti and B promotes the equiaxed crystal transformation of the IN 718 coating microstructure to varying degrees, which is beneficial to the improvement of the mechanical properties of the coating.
[0024] Figure 4 The XRD patterns of the three coatings are shown in Figure 2. Figure 4 It can be seen that the matrix of the coating before and after doping is γ phase, and the strengthening phase is γ' phase (because the γ phase and γ' phase have the same crystal structure and similar lattice constant, their diffraction peaks are highly overlapped). In particular, in the XRD pattern of the IN718 coating, the diffraction peak of the (100) plane has the highest intensity, indicating that the IN718 coating contains a large area of <100> Oriented grains, in Comparative Example 1, after 2wt% Ti and a large amount of B (1wt%) are doped, the grain orientation of the coating is transformed into <110> In Example 1, after 2wt% Ti and trace amount of B (0.05wt%) were co-doped, the orientation of the coating was changed to <111> In addition, according to Figure 4 As a result, after a specific manufacturing process, the individual IN 718 <100> However, after adding 2wt% Ti and 1wt% B in Comparative Example 1, the coating was <110> Orientation is the main factor, that is, the coating orientation changes during the solidification process through the selection of elements and a small amount of doping, which is not predictable by the existing technology. Furthermore, after adding 2wt% Ti and 0.05wt% B in Example 1, the grain orientation of the coating further changes, and the crystal plane orientation of the coating is <111> Orientation-based.
[0025] Figure 5 is the oxidation weight gain curve of the coating at 1000℃. Figure 5 It can be seen that the oxidation resistance of the coating is ranked as Example 1>Comparative Example 1>Comparative Example 2.
[0026] In addition, the XRD ( Figure 4 ) test, the (100), (110) and (111) surface models of the γ phase of the IN 718 coating matrix were constructed according to the orientation information of the coatings with different compositions, as shown in Figure 2. Figure 6 (ac), and on this basis, the adsorption model of O atoms at different sites on different surfaces of the γ phase was constructed. The specific adsorption sites are as follows: Figure 6(df) is shown. On this basis, the adsorption energy of O atoms in each adsorption model is calculated, as shown in Table 1. People in this field should know that: the lower the adsorption energy of O atoms, the more stable the system after adsorption, and the stronger the oxidation resistance of the system. Table 1 lists the adsorption energy of O at different sites on the surface of the γ phase. Based on this, the average value of the adsorption energy of O on each low-index surface of the γ phase is calculated, as shown in Table 2. It can be seen that in the IN 718 coating, the order of the oxidation resistance of the low-index surface is γ(111)>γ(110)>γ(100).
[0027] In summary: First, the addition of trace amounts of B and Ti to IN718 simultaneously improves the oxidation resistance of the coating, which is not found in the prior art. Although B and Ti are present in some coatings in the prior art, their technical effect is not to improve the oxidation resistance. Therefore, this application cannot obtain technical inspiration from the prior art. In addition, the prior art fails to show that adding trace amounts of Ti and B elements to IN718 alloy or other alloys can change the orientation of the coating. In this application, after adding 2Ti1B, a γ(110) crystal plane orientation with better oxidation resistance is obtained, which is an unexpected technical effect. After adjusting the B doping ratio, the orientation of 2Ti0.05B further changes, and the γ(111) crystal plane orientation with the best performance is obtained. The above technical features cannot be technically inspired by the prior art. In addition, this application has achieved unexpected results through doping, changing the crystal plane orientation and greatly improving the oxidation resistance.
[0028] Table 1 O adsorption energies at various low-index surface sites in the γ phase (unit: eV)
[0029] Figure 7 (a) Figure 7 (b) and Figure 8 (a) Figure 8 (b) shows the tensile and compression curves of the coatings from Example 1 and Comparative Example 2 at room temperature and 600°C, respectively. At room temperature, Ti and B doping has little effect on the strength of the IN 718 coating, but it improves its plasticity to varying degrees. This is likely due to the equiaxed grains of the coating after elemental doping. It can also be observed that the co-doping of 2wt% Ti and 0.05wt% B significantly improves both the strength and plasticity of the coating at 600°C.
[0030] It is understood from common technical knowledge that the present invention may be implemented by other embodiments that do not depart from its spirit or essential features. Therefore, the embodiments disclosed above are, in all respects, merely illustrative and not exclusive. All modifications within the scope of the present invention or equivalent to the scope of the present invention are intended to be encompassed by the present invention.
[0031] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the scope of protection of the claims of the present invention.
Claims
1. A method for preparing an IN 718 modified coating, characterized in that: The method comprises: Obtaining a steel base plate and pre-treating the surface of the steel base plate; Commercial IN 718 alloy powder, Ti powder, and B powder are selected and uniformly mixed in a certain proportion to obtain a mixed powder; The pretreated steel substrate plate is placed horizontally on the workbench of the plasma cladding machine, and the mixed powder is put into the powder barrel of the plasma cladding equipment. Under an argon atmosphere, the mixed powder is fed synchronously during the cladding process. After the cladding is completed, the water cooling equipment is immediately turned on to finally obtain the modified IN 718 modified coating.
2. The method for preparing the IN 718 modified coating according to claim 1, wherein: The mixed powder includes: 1.5wt% to 2.5wt% Ti powder, 0.01wt% to 0.1wt% B powder, and the rest is commercial IN 718 alloy powder.
3. The method for preparing the IN 718 modified coating according to claim 2, characterized in that: The particle sizes of the commercial IN 718 alloy powder, the Ti powder and the B powder are all 100-200 meshes.
4. The method for preparing the IN 718 modified coating according to claim 2, characterized in that: The purity of the Ti powder and the B powder is greater than 99.9%.
5. The method for preparing the IN 718 modified coating according to claim 1, characterized in that: The method comprises: selecting commercial IN718 alloy powder, Ti powder and B powder, and uniformly mixing the commercial IN718 alloy powder, Ti powder and B powder in a certain proportion to obtain a mixed powder; The mixed powder was placed in a vacuum drying oven at 80-120°C and dried for 0.5-1.5h.
6. The method for preparing the IN 718 modified coating according to claim 1, characterized in that: The cladding parameters include: spray gun height 9-10 mm, powder feeding gas flow rate 2-3 L / min, ion gas flow rate 2-3 L / min, shielding gas flow rate 2-3 L / min, and cladding current 110A-120A.
7. The method for preparing the IN 718 modified coating according to claim 1, characterized in that: The method of obtaining a steel base plate and pre-treating the surface of the steel base plate comprises: The steel substrate plate is polished smooth, and then its surface is cleaned with alcohol. The cleaned steel substrate plate is then placed in a vacuum drying oven at 80-120°C and dried for 10-30 minutes.
8. An IN 718 modified coating prepared according to the method for preparing an IN 718 modified coating according to any one of claims 1 to 7.