Preparation method of oxide dispersion strengthened alloy, forming method of servo valve and servo valve

Abstract

The invention discloses a preparation method of an oxide dispersion strengthened alloy, a forming method of a servo valve and the servo valve, and relates to the technical field of servo valves.The preparation method of the oxide dispersion strengthened alloy comprises the following steps that alloy matrix raw material powder and preset oxide raw material powder are provided to be subjected to preset machining and mixing; mixed powder is obtained; establishing a three-dimensional model, and performing slicing processing on the established three-dimensional model to obtain slicing information; the cycle of laying the mixed powder layer by layer and spraying a preset binder in a preset mode is conducted on the basis of slicing information, and a green body is obtained; and the green body is cured, degreased and sintered in sequence, and the oxide dispersion strengthened alloy is obtained. The oxide dispersion strengthened alloy prepared through the method is stable in structure and good in mechanical property, the use reliability is improved, the oxide dispersion strengthened alloy formed through the method can be applied to structures or equipment in different fields, and the use range is expanded.

Description

Technical Field

[0001] The present invention relates to the technical field of servo valves, and in particular to a method for preparing an oxide dispersion strengthened alloy, a method for forming a servo valve, and a servo valve. Background Art

[0002] At present, the steel types commonly used in servo valves, such as stainless steel and alloy steel, may face problems such as reduced strength and insufficient wear resistance under high temperature and high pressure environments. The performance limitations of these materials under extreme conditions may lead to reduced accuracy and life of the servo valve. Oxide dispersion strengthened steel has excellent high temperature mechanical properties and wear resistance, and can maintain stable mechanical properties in high temperature and high pressure environments. At the same time, its excellent oxidation resistance and creep resistance make it an ideal material choice for servo valves under harsh conditions. This greatly improves the reliability and service life of the servo valve, making it suitable for demanding industrial and aerospace applications.

[0003] However, the current process for producing servo valves using oxide dispersion strengthened steel is usually laser 3D printing. Since this printing process is accompanied by rapid melting and solidification processes, the formed oxide dispersion strengthened steel has many problems such as many microcracks and poor mechanical properties. Summary of the invention

[0004] The main purpose of the present invention is to provide a preparation method of an oxide dispersion strengthened alloy, a forming method of a servo valve and a servo valve, aiming to improve the mechanical properties of the oxide dispersion strengthened steel after forming.

[0005] To achieve the above object, the method for preparing the oxide dispersion strengthened alloy proposed in the present invention comprises the following steps: Providing alloy matrix raw material powder and preset oxide raw material powder for preset processing and mixing to obtain mixed powder; Establishing a three-dimensional model, slicing the established three-dimensional model, and obtaining slicing information; Laying the mixed powder layer by layer based on the slice information and spraying a preset binder in a preset manner to obtain a green body; The green body is solidified, degreased and sintered in sequence to obtain an oxide dispersion strengthened alloy.

[0006] The oxide dispersion strengthened alloy is obtained by printing through this method. The prepared oxide dispersion strengthened alloy has a stable structure and good mechanical properties, which improves the reliability of use. The oxide dispersion strengthened alloy formed by this method can be used in structures or equipment in different fields, expanding the scope of use.

[0007] In one embodiment, laying the mixed powder layer by layer based on the slice information and spraying a preset binder in a preset manner to obtain a green body specifically comprises the following steps: Lay the mixed powder with a preset thickness based on the first-level slice information of the 3D model; Using high pressure spraying of a preset binder on the surface of the paved mixed powder material, so that the preset binder penetrates into the gaps of the mixed powder material; The steps of laying mixed powder and spraying preset binder are cyclically performed in sequence based on different layers until the printing of all layers is completed to obtain a green body.

[0008] The slice thickness can be adjusted through data. After the mixed powder is laid, the preset binder is sprayed with a high-pressure nozzle, so that the binder penetrates into the gap under pressure, so as to better bond the powder and have sufficient mechanical properties; printing layer by layer makes the final oxide dispersion strengthened alloy structure stable and consistent. The mechanical properties are better.

[0009] In one embodiment, the alloy matrix raw material powder includes one or more of stainless steel, mold steel, alloy steel, and carbon steel; the preset oxide raw material powder includes one or more of yttrium oxide, aluminum oxide, titanium dioxide, magnesium oxide, and zirconium dioxide powder.

[0010] Different types of oxide raw materials will result in different mechanical properties of the oxide dispersion strengthened alloy after forming. When multiple oxide raw materials are added, the mechanical properties of the oxide dispersion strengthened alloy will be significantly improved, thereby obtaining an oxide dispersion strengthened alloy with better mechanical properties.

[0011] In one embodiment, the particle size of the alloy matrix raw material powder is 15-100 μm, and the laying thickness of the powder layer is 3-10 times the particle size of the alloy matrix raw material powder.

[0012] The particle size of the alloy raw material powder is determined by the preset processing and mixing process, and the thickness of the laid powder layer is related to the preset sprayed binder. In order to ensure the structure and mechanical properties of the oxide dispersion strengthened alloy after forming, the binder needs to fully penetrate into the gaps of the powder to form adhesion. Through this design, the particle size of the alloy matrix raw material powder is restricted, and the thickness of the powder layer is restricted, so as to obtain a better oxide dispersion strengthened alloy.

[0013] In one embodiment, the predetermined adhesive includes one or more of epoxy resin, phenolic resin, polymer-based adhesive, and water-based adhesive.

[0014] In one embodiment, the saturation of the preset binder is 20%-80%, each slice is paved with at least one layer of powder, and the thickness of the powder is inversely proportional to the saturation of the preset binder.

[0015] The preset binder saturation is the proportion of the binder filling the powder gaps. It is also a factor that affects the powder bonding performance and the difficulty of removing the binder in post-processing. By determining the relationship between the powder layer laying thickness and the binder saturation through this design, the operating difficulty and efficiency of the process can be intuitively controlled, while also ensuring the mechanical properties of the final oxide dispersion strengthened alloy.

[0016] The present invention also provides a forming method of a servo valve, which specifically comprises the following steps: Providing alloy matrix raw material powder and preset oxide raw material powder for preset processing and mixing to obtain mixed powder; Establishing a servo valve three-dimensional model, slicing the established servo valve three-dimensional model, and obtaining all slicing information; Laying the mixed powder layer by layer based on the slice information and spraying a preset binder in a preset manner to obtain a green body; The servo valve green body is sequentially subjected to powder cleaning, solidification, degreasing and sintering to obtain the required servo valve.

[0017] The forming method of the servo valve has the same beneficial effects as the preparation method of the oxide dispersion strengthened alloy described above, and will not be described in detail here.

[0018] In one embodiment, the preset oxide raw material powder accounts for 0.1%-49% of the mass percentage of the alloy matrix raw material powder; Degreasing is performed under gas circulation, wherein the degreasing temperature of the green body is in the range of 300°C to 900°C, the single degreasing time is in the range of 0.5 h to 24 h, and the degreasing cycle is 1 to 10 times; The sintering is carried out in a vacuum or inert atmosphere under pressure. The sintering temperature of the green body is in the range of 1000°C to 1550°C, the single sintering time is in the range of 0.5 h to 24 h, and the sintering cycle is in the range of 1 to 10 times.

[0019] The mass percentages of the oxide raw materials and the alloy matrix raw materials are different, and the types used are different. The mechanical properties and high-temperature properties of the oxide dispersion-strengthened alloys finally formed are different. Therefore, the mass percentages of the oxide raw materials and the alloy matrix raw materials are limited, so that the oxide dispersion-strengthened alloys with the best performance can be obtained for different types, and the best performance results can be obtained when used on the forming servo valve; the setting of various parameters for green body degreasing and sintering helps to quickly remove the binder from the green body and form a solid bond between the powder particles through high-temperature sintering, so as to obtain a product with better density.

[0020] In one embodiment, the components of the servo valve are integrally formed or individually formed, and each component is printed using mixed powders having the same or different mass percentages of oxide materials.

[0021] The performance requirements of various components of the servo valve are different during use. Through this design, the mass percentage of oxide raw materials and alloy matrix raw materials is purposefully selected to generate components, which can improve the performance required by the component in a targeted manner. For components that do not require excessive performance, the raw material requirements during production can be reduced, thereby saving costs.

[0022] The present invention also provides a servo valve, which is formed using the servo valve forming method as described above.

[0023] The servo valve has the same beneficial effects as the forming method of the servo valve described above, which will not be described in detail here. The technical solution of the present invention adopts single-layer printing that slices the three-dimensional model, lays powder layer by layer, and sprays a binder, so as to avoid the problems of many microcracks and poor mechanical properties of the oxide dispersion strengthened steel after forming caused by the use of laser printing. Finally, the binder is removed through post-treatment such as powder cleaning, curing, degreasing and sintering, and the structure of the mixed powder after forming is retained. As the required oxide dispersion strengthened alloy, the oxide dispersion strengthened alloy can be used in other application fields through the 3D printing method to improve or even enhance its structural performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0025] Figure 1 A flow chart of the steps of the method for preparing the oxide dispersion strengthened alloy provided by the present invention; Figure 2 A flow chart of step S3 in the method for preparing the oxide dispersion strengthened alloy provided by the present invention; Figure 3 A flow chart of the steps of the forming method of the servo valve provided by the present invention; Figure 4 A schematic diagram of the microstructure of the mixed powder in the forming method of the servo valve provided by the present invention; Figure 5 A schematic diagram of the microstructure of the green body after sintering in the forming method of the servo valve provided by the present invention; Figure 6 This is a schematic structural diagram of the servo valve provided by the present invention.

[0026] Description of Figure Numbers: 100. Servo valve. The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] It should be noted that if there are directional indications (such as up, down, left, right, front, back, etc.) involved in the embodiments of the present invention, the directional indication is only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly. Unless otherwise clearly specified and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, and it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0029] In addition, if there are descriptions related to "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" can explicitly or implicitly include at least one of the features. Moreover, the terms "include", "comprise", or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article, or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article, or device. In the absence of more restrictions, the elements defined by the sentence "include one..." do not exclude the existence of other identical elements in the process, method, article, or device including the elements. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel schemes, taking "A and / or B" as an example, including scheme A, or scheme B, or schemes that A and B meet at the same time. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0030] Servo valves are used in aerospace and industrial fields such as inside aircraft engines, rocket propulsion systems, and high-temperature processing equipment. They need to be able to operate stably and for a long time under high temperature and high pressure conditions. Therefore, it is necessary to select suitable materials and optimize the design to enhance their high-temperature mechanical properties.

[0031] At present, the steel types commonly used in servo valves, such as stainless steel and alloy steel, may face problems such as reduced strength and insufficient wear resistance under high temperature and high pressure environments. The performance limitations of these materials under extreme conditions may lead to reduced accuracy and life of the servo valve. ODS steel has excellent high-temperature mechanical properties and wear resistance, and can maintain stable mechanical properties in high temperature and high pressure environments. At the same time, its excellent oxidation resistance and creep resistance make it an ideal material choice for servo valves under harsh conditions. This greatly improves the reliability and service life of the servo valve, making it suitable for demanding industrial and aerospace applications.

[0032] However, the current process for producing servo valves using ODS steel is usually laser 3D printing. Due to the rapid melting and solidification process, the main problems of the formed ODS steel, such as many microcracks and poor mechanical properties, have not been effectively solved.

[0033] The invention provides a method for preparing an oxide dispersion strengthened alloy.

[0034] See also Figure 1 In one embodiment of the present invention, the method for preparing the oxide dispersion strengthened alloy comprises the following steps: S1: providing alloy matrix raw material powder and preset oxide raw material powder for preset processing and mixing to obtain mixed powder; S2: Establishing a three-dimensional model, slicing the established three-dimensional model, and obtaining slicing information; S3: laying the mixed powder layer by layer based on the slice information, spraying a preset binder in a preset manner, and obtaining a green body; S4: The green body is solidified, degreased and sintered in sequence to obtain an oxide dispersion strengthened alloy.

[0035] It should be noted that the preset processing and mixing of the alloy matrix raw material powder and the preset oxide raw material powder is specifically to ball mill the alloy matrix raw material powder and the preset oxide raw material powder until the two powders are evenly dispersed, so that the preset oxide raw material powder adheres to the surface of the alloy matrix raw material powder, thereby obtaining a mixed powder.

[0036] Specifically, the particle size of the alloy matrix raw material powder is 15-100 μm, and the particle size of the preset oxide raw material powder is 10-100 nm.

[0037] Preferably, the particle size of the alloy matrix raw material powder is 15-53 μm, and the particle size of the preset oxide raw material powder is 10-50 nm.

[0038] It can be understood that the oxide dispersion strengthened alloy obtained by printing through this method, the prepared oxide dispersion strengthened alloy (hereinafter referred to as ODS steel) has a stable structure, good thermal and mechanical properties, and improved reliability of use. The oxide dispersion strengthened alloy formed by this method can be used in structures or equipment in different fields, expanding the scope of use.

[0039] See also Figure 2 In one embodiment, the mixed powder is laid layer by layer based on the slice information, and a preset binder is sprayed in a preset manner to obtain a green body, which specifically includes the following steps: S31: Based on the first-level slice information of the three-dimensional model, laying the mixed powder with a preset thickness; S32: using high pressure spraying of a preset binder on the surface of the paved mixed powder material, so that the preset binder penetrates into the gaps of the mixed powder material; S33: Based on different layers, the steps of laying mixed powder and spraying preset binder are cyclically performed in sequence until the printing of all layers is completed to obtain a green body.

[0040] Understandably, the slice thickness can be adjusted through data, and after the mixed powder is laid, a preset binder is sprayed with a high-pressure nozzle, so that the binder penetrates into the gap under pressure, thereby better bonding the powder and having sufficient mechanical properties; printing layer by layer makes the final oxide dispersion strengthened alloy structure stable and consistent. The mechanical properties are better.

[0041] In one embodiment, each slice is paved with at least one layer of powder.

[0042] It should be noted that there is no limit on the number of times each level of slicing is applied with powder. Powder of a preset thickness can be applied at one time, or powder of proportional thickness can be applied in batches.

[0043] Specifically, in a specific embodiment of the present invention, each level of slices is powdered once, and after powdering, the preset binder is sprayed once.

[0044] This design can reduce the number of slices and save the time required for slicing. At the same time, it can reduce the number of times of powdering and save the time of powdering, thereby improving work efficiency.

[0045] In one embodiment, the alloy matrix raw material powder includes one or more of stainless steel, mold steel, alloy steel, and carbon steel; the preset oxide raw material powder includes one or more of yttrium oxide, aluminum oxide, titanium dioxide, magnesium oxide, and zirconium dioxide powder.

[0046] It should be noted that the preset oxide raw material powders can be used alone as oxides. If multiple raw materials need to be mixed, yttrium titanium oxide (Y-Ti-O) and aluminum magnesium oxide (Al-Mg-O) are usually selected. Both can be obtained by mixing yttrium trioxide (Y2O3) with titanium dioxide (TiO2), or by mixing aluminum trioxide (Al2O3) with magnesium oxide (MgO). The oxide dispersion strengthened alloy obtained by this mixture has better performance.

[0047] Specifically, the alloy matrix raw material powder includes various steel grades such as 06Cr18Ni11Ti, 102Cr17Mo, 17Cr16Ni2, 05Cr17Ni4Cu4Nb, 05Cr15Ni5Cu4Nb, 04Cr13Ni8Mo2Al, 01Cr12Ni11Mo1Ti, 01Cr12Ni11Mo2Al1.5Ti, 022Cr13Ni8Mo3Al, 02Cr12Ni9Mo4Cu2Al, X3NiCoMoTi18-9-5, and 022Cr17Ni12Mo2.

[0048] It is understandable that different types of oxide raw materials will result in different mechanical properties of the oxide dispersion strengthened alloy after forming. When multiple oxide raw materials are added, the mechanical properties of the oxide dispersion strengthened alloy will be significantly improved, thereby obtaining an oxide dispersion strengthened alloy with better mechanical properties.

[0049] In one embodiment, the predetermined adhesive includes one or more of epoxy resin, phenolic resin, polymer-based adhesive, and water-based adhesive.

[0050] It should be noted that different viscosities of adhesive raw materials will clog the nozzle to different degrees during use, and the temperatures required for final curing and removal of the adhesive are different. The amount of adhesive residue when removed is different, that is, the difficulty of removing the adhesive is different.

[0051] In one embodiment, the thickness of the powder layer is 3-10 times the particle size of the mixed powder.

[0052] The particle size of the alloy raw material powder is determined by the preset processing and mixing process, and the thickness of the laid powder layer is related to the preset sprayed binder. In order to ensure the structure and mechanical properties of the oxide dispersion strengthened alloy after forming, the binder needs to fully penetrate into the gaps of the powder to form adhesion. Through this design, the particle size of the alloy matrix raw material powder is restricted, and the thickness of the powder layer is restricted, so as to obtain a better oxide dispersion strengthened alloy.

[0053] In one embodiment, the saturation of the preset binder is 20%-80%, and the powder coating thickness is inversely proportional to the saturation of the preset binder.

[0054] It should be noted that the saturation of the preset binder is the proportion of the binder filling the powder gaps. It is also a factor that affects the powder bonding performance and the difficulty of removing the binder in post-processing. The thicker the powder layer, the more gaps there are in the powder layer, and the more difficult it is to fill them with sprayed preset binder. Therefore, the saturation of the preset binder is lower.

[0055] Preferably, the saturation of the preset binder is 30%-50%, at which point the bonding performance of the mixed powder is optimal.

[0056] It can be understood that by determining the relationship between the powder layer laying thickness and the binder saturation through this design, the operating difficulty and efficiency of the process can be intuitively controlled, while also ensuring the mechanical properties of the final result of the oxide dispersion strengthened alloy.

[0057] The technical solution of the present invention adopts single-layer printing that slices the three-dimensional model, lays powder layer by layer, and sprays a binder, so as to avoid the problems of many microcracks and poor mechanical properties of the oxide dispersion strengthened steel after forming caused by the use of laser printing. Finally, the binder is removed through post-treatment such as powder cleaning, curing, degreasing and sintering, and the structure of the mixed powder after forming is retained. As the required oxide dispersion strengthened alloy, the oxide dispersion strengthened alloy can be used in other application fields through the 3D printing method to improve or even enhance its structural performance.

[0058] See also Figure 3-Figure 5 The present invention also provides a servo valve forming method, which uses an oxide dispersion strengthened alloy preparation method to form a servo valve, specifically comprising the following steps: S101: providing alloy matrix raw material powder and preset oxide raw material powder for preset processing and mixing to obtain mixed powder; S102: Establishing a servo valve three-dimensional model, and slicing the established servo valve three-dimensional model to obtain all slice information; S103: laying the mixed powder layer by layer based on the slice information, spraying a preset binder in a preset manner, and obtaining a green body; S104: The servo valve green body is solidified, degreased and sintered in sequence to obtain the required servo valve.

[0059] It should be noted that before or after solidifying the servo valve green body, the mixed powder on the green body surface is also removed, that is, the powder cleaning step. Specifically, after the green body is obtained by printing layer by layer based on the slice information using the mixed powder, some mixed powder will usually remain on the green body surface, so the residual mixed powder needs to be removed; Since the green body has just been formed, its overall performance is poor and not as good as the performance of the final product after post-processing. Therefore, when performing the powder cleaning step, it is necessary to prioritize ensuring that the overall structure of the green body is not damaged. The green body solidification step uses equipment to quickly solidify the green body into a harder texture. At this time, removing the surface powder of the solidified green body will greatly reduce the difficulty of powder cleaning.

[0060] In summary, there is no specific limitation on the powder cleaning process of the servo valve green body, which can be performed before or after solidification, as long as the powder cleaning step does not damage the shape and structure of the servo valve green body.

[0061] Preferably, in a specific embodiment of the invention, the powder cleaning step is arranged between solidification and degreasing, with the purpose of more efficiently cleaning the powder on the surface of the green body after solidification and improving the powder cleaning efficiency.

[0062] The forming method of the servo valve has the same beneficial effects as the preparation method of the oxide dispersion strengthened alloy described above, and will not be described in detail here.

[0063] In one embodiment, the preset oxide raw material powder accounts for 0.1%-49% of the alloy matrix raw material powder by mass.

[0064] Preferably, the preset oxide raw material powder accounts for 0.1%-25% of the alloy matrix raw material powder by mass.

[0065] In one embodiment, debinding is performed under gas circulation, the debinding temperature of the green body is in the range of 200°C to 950°C, the single debinding time is in the range of 0.5 h to 24 h, and the debinding cycle is 5 times; Preferably, debinding is performed under gas circulation, the debinding temperature of the green body is in the range of 300°C-900°C, the single debinding time is in the range of 0.5 h-24 h, and the debinding cycle is 1-10 times.

[0066] In one embodiment, sintering is performed in a vacuum or inert atmosphere under pressure, the sintering temperature of the green body is in the range of 980° C.-1600° C., the single sintering time is in the range of 0.5 h-24 h, and the sintering cycle is 1-10 times.

[0067] Preferably, the sintering is carried out in an inert atmosphere under pressure, the sintering temperature of the green body is in the range of 1000°C-1550°C, the single sintering time is in the range of 0.5 h-24 h, and the sintering cycle is 5 times.

[0068] It should be noted that the mass percentages of the oxide raw material and the alloy matrix raw material are different, and the types used are different, so the mechanical properties and high-temperature properties of the final oxide dispersion-strengthened alloy are different; the preset oxide raw material is coated on the outer surface of the alloy matrix raw material powder after ball milling. Therefore, the greater the mass percentage of the oxide raw material, the larger the area of ​​the coated alloy matrix material, and the more the mechanical properties and high-temperature properties of the final oxide dispersion-strengthened alloy are improved.

[0069] Therefore, the mass percentage ratio of the oxide raw material and the alloy matrix raw material is limited, so that even if the oxide raw material and the alloy matrix raw material are of different types, the oxide dispersion strengthened alloy with the best performance can be obtained by adjusting the mass percentage ratio, and the best performance can be obtained by using it on the forming servo valve. The setting of various parameters for green body debinding and sintering helps to quickly remove the binder from the green body and form a solid bond between the powder particles through high-temperature sintering, thereby obtaining a product with better density.

[0070] In addition, degreasing can be a long-term operation or multiple short-term operations. In the case of multiple operations, cooling time can be reserved between each two degreasing processes, and the next operation can be performed again after the oxide dispersion strengthened alloy drops to the preset temperature; degreasing by changing the temperature gradient can also be completed without reserving cooling time, thereby achieving a better degreasing effect and improving the efficiency of degreasing; Similarly, sintering can be a long-term operation or multiple short-term operations. In the case of multiple operations, cooling time can be reserved between each two sintering processes, and the next operation can be performed again after the oxide dispersion strengthened alloy drops to the preset temperature; it is also possible to complete the temperature gradient sintering by changing the temperature without reserving a cooling time, thereby achieving a better sintering effect and improving the sintering efficiency; For details, please combine Figure 4-Figure 5 , Figure 4 Schematic diagram of the microstructure of the green body after degreasing. The agglomerated substances that stick to each other in the figure are mixed powders, and the scattered granular substances on the surface of the mixed powders are oxides. Figure 5 This is a schematic diagram of the microstructure of the green body after high-temperature sintering after degreasing. The lumps of matter that are bonded to each other in the figure are the mixed powder, and the matter tightly embedded on the surface of the mixed powder is the oxide.

[0071] In one embodiment, the components of the servo valve are integrally formed or individually formed, and each component is printed using mixed powders having the same or different mass percentages of oxide materials.

[0072] The performance requirements of various components of the servo valve are different during use. Through this design, the mass percentage of oxide raw materials and alloy matrix raw materials is purposefully selected to generate components, which can improve the performance required by the component in a targeted manner. For components that do not require excessive performance, the raw material demand during production can be reduced, thereby reducing the temperature during solidification and sintering, saving solidification and sintering time to improve efficiency.

[0073] Specifically, in a specific embodiment of the present invention, forming a servo valve using ODS steel specifically includes the following steps: Two groups of 316 stainless steel powder with a particle size of 75 μm were weighed and placed in two ball mills, and 0.2 wt% of Y2O3 powder with an average particle size of 20 nm and 0.4 wt% of Y2O3 powder with an average particle size of 20 nm were added respectively; The ratio of grinding balls to powders was set to 10:1, the ball milling speed was 380 r / min, and the ball milling time was 60 h to obtain the desired mixed powder; The models of the servo valve body and valve core are established respectively, and the slices are processed separately using software, and the slice information of each is obtained; Based on the slice information, a powder layer with a thickness of 40 μm is laid, and a phenolic resin binder with a saturation of 30% is sprayed and printed layer by layer to obtain a valve body green body of the servo valve; and, based on the slice information, a powder layer with a thickness of 40 μm is laid, and a phenolic resin binder with a saturation of 35% is sprayed and printed layer by layer to obtain a valve core green body of the servo valve; The two green pieces were cleaned of excess powder on the surface and placed in an oven for curing. The two green pieces after curing were then moved to a sintering furnace and heated to 600℃ for 2 h for complete degreasing. The degreased servo valve body green body is densified and sintered at 1100°C for 2 h, and the servo valve body product is obtained after the sintering furnace is cooled to room temperature; the degreased servo valve core green body is densified and sintered at 1200°C for 2 h, and the servo valve core product is obtained after the sintering furnace is cooled to room temperature.

[0074] See also Figure 6 The present invention further provides a servo valve 100, which is formed using the servo valve forming method as described above.

[0075] The servo valve 100 has the same beneficial effects as the forming method of the servo valve described above, which will not be described in detail herein.

[0076] It should be understood that the "one implementation method" or "one embodiment" mentioned throughout the specification means that the specific features, structures or characteristics related to the embodiment are included in at least one embodiment of the present invention. Therefore, "in one implementation method" or "in one embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. In addition, these specific features, structures or characteristics can be combined in one or more embodiments in any suitable manner. Those skilled in the art should also be aware that the embodiments described in the specification are all optional embodiments, and the actions and modules involved are not necessarily required by the present invention.

[0077] In various embodiments of the present invention, it should be understood that the size of the serial numbers of the above-mentioned processes does not mean the necessary order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0078] The flow chart and block diagram in the accompanying drawings of the present invention illustrate the possible architecture, function and operation of the system, method and computer program product according to various embodiments of the present application. In this regard, each box in the flow chart or block diagram can represent a module, a program segment or a part of a code, and the module, the program segment or a part of the code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a sequence different from that marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, which is determined based on the functions involved. It should be particularly noted that each box in the block diagram and / or flow chart, and the combination of the boxes in the block diagram and / or flow chart can be implemented by a dedicated hardware-based system that performs a specified function or operation, or can be implemented by a combination of dedicated hardware and computer instructions.

[0079] The above description is only an exemplary embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for preparing an oxide dispersion strengthened alloy, characterized in that: The steps include: Providing alloy matrix raw material powder and preset oxide raw material powder for preset processing and mixing to obtain mixed powder; Establishing a three-dimensional model, slicing the established three-dimensional model, and obtaining slicing information; Laying the mixed powder layer by layer based on the slice information and spraying a preset binder in a preset manner to obtain a green body; The green body is solidified, degreased and sintered in sequence to obtain an oxide dispersion strengthened alloy.

2. The method for preparing an oxide dispersion strengthened alloy according to claim 1, characterized in that: The mixed powder is laid layer by layer based on the slice information, and a preset binder is sprayed in a preset manner to obtain a green body, which specifically includes the following steps: Lay the mixed powder with a preset thickness based on the first-level slice information of the 3D model; Using high pressure spraying of a preset binder on the surface of the paved mixed powder material, so that the preset binder penetrates into the gaps of the mixed powder material; The steps of laying mixed powder and spraying preset binder are cyclically performed in sequence based on different layers until the printing of all layers is completed to obtain a green body.

3. The method for preparing an oxide dispersion strengthened alloy according to claim 1, characterized in that: The laying thickness of the powder layer is 3-10 times of the particle size of the mixed powder.

4. The method for preparing an oxide dispersion strengthened alloy according to claim 1, wherein: The alloy matrix raw material powder includes one or more of stainless steel, mold steel, alloy steel, and carbon steel; the preset oxide raw material powder includes one or more of yttrium oxide, aluminum oxide, titanium dioxide, magnesium oxide, and zirconium dioxide powder.

5. The method for preparing an oxide dispersion strengthened alloy according to claim 1, characterized in that: The preset adhesive includes one or more of epoxy resin, phenolic resin, polymer-based adhesive and water-based adhesive.

6. The method for preparing an oxide dispersion strengthened alloy according to claim 1, characterized in that: The saturation of the preset binder is 20%-80%, and each slice is paved with at least one layer of powder, and the thickness of the powder is inversely proportional to the saturation of the preset binder.

7. A method for forming a servo valve, characterized in that: The specific steps include: Providing alloy matrix raw material powder and preset oxide raw material powder for preset processing and mixing to obtain mixed powder; Establishing a servo valve three-dimensional model, slicing the established servo valve three-dimensional model, and obtaining all slicing information; Laying the mixed powder layer by layer based on the slice information and spraying a preset binder in a preset manner to obtain a green body; The servo valve green body is solidified, degreased and sintered in sequence to obtain the required servo valve.

8. The method for forming a servo valve according to claim 7, characterized in that: The preset oxide raw material powder accounts for 0.1%-49% of the mass percentage of the alloy matrix raw material powder; Degreasing is performed under gas circulation, wherein the degreasing temperature of the green body is in the range of 300°C to 900°C, the single degreasing time is in the range of 0.5 h to 24 h, and the degreasing cycle is 1 to 10 times; The sintering is carried out in a vacuum or inert atmosphere under pressure. The sintering temperature of the green body is in the range of 1000°C to 1550°C, the single sintering time is in the range of 0.5 h to 24 h, and the sintering cycle is in the range of 1 to 10 times.

9. The method for forming a servo valve according to claim 8, characterized in that: The components of the servo valve are formed in one piece or separately, and the components are printed using mixed powders with the same or different mass percentages of oxide materials.

10. A servo valve, characterized in that: The servo valve is formed using the forming method as described in any one of claims 7 to 9.

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