Nickel-based high-temperature alloy powder, nickel-based high-temperature alloy part and preparation method of nickel-based high-temperature alloy part

Abstract

The invention relates to nickel-based high-temperature alloy powder, a nickel-based high-temperature alloy part and a preparation method of the nickel-based high-temperature alloy part, and relates to the technical field of nickel-based high-temperature alloys. According to the main technical scheme, the preparation method of the nickel-based high-temperature alloy powder comprises the following steps that a nickel-based high-temperature alloy master alloy ingot is prepared into alloy powder; the alloy powder is subjected to ball milling treatment, alloy powder subjected to ball milling treatment is obtained, and the particle size of the alloy powder subjected to ball milling treatment ranges from 5 micrometers to 60 micrometers; the alloy powder obtained after ball milling treatment is screened out, and alloy powder of various particle sizes is screened out; then, the alloy powder of various particle sizes is mixed so as to reduce gaps among the alloy powder, and nickel-based high-temperature alloy powder is obtained; after the nickel-based high-temperature alloy powder prepared by the method is molded by an additive technology, uniform and compact parts with excellent mechanical properties can be obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of nickel-based high-temperature alloys, and in particular to nickel-based high-temperature alloy powder, a nickel-based high-temperature alloy part and a preparation method thereof. Background Art

[0002] Nickel-based superalloys have excellent creep properties, fatigue strength, good corrosion resistance and environmental stability, and are widely used in hot-end components in the aerospace field, especially engine turbines. Nickel-based superalloys mainly rely on solid solution strengthening and γ′ precipitation strengthening to improve their mechanical properties. Since nickel-based superalloys can obtain a large amount of high-cubic γ′ precipitation phase after solid solution treatment and aging treatment, they still have high fatigue strength and tensile strength without forging. At present, they have become an irreplaceable key material in aero engines.

[0003] With the increasing maturity of additive manufacturing technology and the significant reduction in costs, its application scope, depth and scale are constantly breaking through, and it has gradually been applied to the aerospace field. Among them, the use of additive manufacturing technology to prepare nickel-based high-temperature alloy parts is the most widely used. Compared with traditional cast and forged high-temperature alloys, high-temperature alloy parts prepared from nickel-based high-temperature alloy powders by additive manufacturing technology have the advantages of uniform organization, no macroscopic segregation, high yield strength, and good fatigue performance. They overcome the segregation caused by conventional processes. Each particle of the pre-alloyed powder used is a "microscopic ingot". Alloy segregation can only occur within a small range of powder particles, which can improve the comprehensive performance of the alloy, reduce the amount of cutting processing, and improve the utilization rate of the alloy. Especially with the increasingly complex composition of high-temperature alloys and the increasing size of parts, powder metallurgy high-temperature alloys show greater superiority.

[0004] The size and uniformity of nickel-based high-temperature alloy powder directly determine the density and mechanical properties of parts after additive manufacturing. Therefore, how to adjust the powder size and uniformity of nickel-based high-temperature alloy is the key to high-temperature alloy additive manufacturing. Summary of the invention

[0005] In view of this, the present invention provides a nickel-based high-temperature alloy powder, a nickel-based high-temperature alloy part and a preparation method thereof, the main purpose of which is to prepare a nickel-based high-temperature alloy powder with a small powder void ratio, so as to obtain a highly dense nickel-based high-temperature alloy part through additive manufacturing, thereby greatly improving its mechanical properties.

[0006] In order to achieve the above object, the present invention mainly provides the following technical solutions:

[0007] In one aspect, an embodiment of the present invention provides a method for preparing a nickel-based high-temperature alloy powder, comprising the following steps:

[0008] Powder making step: preparing nickel-based high-temperature alloy master alloy ingot into alloy powder;

[0009] Ball milling step: ball milling the alloy powder to obtain the alloy powder after ball milling; wherein the particle size of the alloy powder after ball milling is 5-60 μm;

[0010] Screening and mixing step: Screening the alloy powder after ball milling to screen out alloy powders of various particle sizes; then, mixing the alloy powders of various particle sizes to reduce the gaps between the alloy powders to obtain nickel-based high-temperature alloy powder.

[0011] Preferably, the alloy powders of the plurality of particle sizes include a first particle size grade alloy powder, a second particle size grade alloy powder, and a third particle size grade alloy powder; wherein, the particle size D1 of the first particle size grade alloy powder is: 10<D1≤20μm; the particle size D2 of the second particle size grade alloy powder is: 20<D2≤40μm; the particle size D3 of the third particle size grade alloy powder is: 40<D3≤50μm; preferably, the mass proportion of the first particle size grade alloy powder in the nickel-based high-temperature alloy powder is 30-35%; the mass proportion of the second particle size grade alloy powder in the nickel-based high-temperature alloy powder is 45-50%; the mass proportion of the third particle size grade alloy powder in the nickel-based high-temperature alloy powder is 20-25%.

[0012] Preferably, the particle size D1 of the first size grade alloy powder and the particle size D2 of the second size grade alloy powder are calculated by the following formula.

[0013]

[0014] The powder particle size calculated according to the above formula can achieve the densest stacking state, thereby improving the density and strength of the parts after forming. The D3 grade uses a relatively large particle size mainly to improve the fluidity of the powder and prevent the powder from agglomerating during the forming process, resulting in uneven powder spreading.

[0015] It should be noted that the particle size calculation formulas for D1 and D2 meet the requirements of the most dense packing, and the particle size of D3 provides fluidity. Therefore, the theoretical packing model ratio obtained according to the above formula is D1:D2:D3≈3:4:2 (i.e., the particle size ratios of each level are approximately equal to 30-35%, 45-50%, and 20-25%, respectively).

[0016] Preferably, the chemical composition of the nickel-based high-temperature alloy powder is as follows, in terms of weight percentage: C: 0.12-0.16wt%, Cr: 8.00-9.50wt%, Co: 9.00-10.50wt%, Mo: 1.20-2.40wt%, Al: 5.10-5.70wt%, Ti: 2.00-2.90wt%, W: 9.50-11.00wt%, Nb: 0.80-1.20wt%, rare earth elements: 0.015-0.03wt%; grain boundary strengthening elements: 0.015-0.035wt%, and the balance is Ni;

[0017] Preferably, the rare earth elements include Y and Ce; wherein, in the nickel-based high-temperature alloy powder, the mass fraction of the Y element is 0.005-0.01wt%, and the mass fraction of the Ce element is 0.01-0.02wt%;

[0018] Preferably, the grain boundary strengthening element includes element B; wherein, in the nickel-based high-temperature alloy powder, the mass fraction of element B is 0.015-0.035wt%.

[0019] Preferably, the preparation steps of the nickel-based high-temperature alloy master alloy ingot are as follows:

[0020] According to the chemical composition, the first raw material is charged into the furnace and vacuumed. When the vacuum degree is less than 50Pa, power is supplied to start melting until the first raw material is completely melted; then the first refining treatment is carried out; after the first refining treatment, the power is turned off and the temperature is lowered to the metal liquid condensation film state, and the second raw material is added to the alloy liquid through the side feeding bin, and then the second refining treatment is carried out; after the second refining treatment is completed, the temperature is raised to the pouring temperature for pouring to obtain a nickel-based high-temperature alloy mother alloy ingot; preferably, the order of charging the first raw material into the furnace is: cobalt, carbon, tungsten, molybdenum, niobium, chromium, nickel; preferably, the order of adding the second raw material is: aluminum, aluminum yttrium, nickel cerium, titanium, nickel boron.

[0021] Preferably, the temperature of the high temperature refining treatment is 1500±30°C, and the time of the high temperature refining treatment is 50±10min; preferably, the temperature of the low temperature refining treatment is 1400±30°C, and the time of the low temperature refining treatment is 50±10min; preferably, the pouring temperature is 1450±30°C. Preferably, in the powder making step: the nickel-based high temperature alloy master alloy ingot is made into alloy powder by vacuum gas atomization; preferably, the particle size of the alloy powder is 7-68μm; preferably, the morphology of the alloy powder is an irregular sphere with edges and corners; preferably, the atomization pressure is 3.5±0.5MPa, and the atomization gas temperature is 100±10°C.

[0022] Preferably, in the ball milling step: the diameter of the grinding balls is 3-5 mm, the ball-to-material ratio is (15-17):1, the ball milling time is 2±0.2 h, and the rotation speed is 280±20 r / min; and / or a planetary vacuum ball mill is used to ball mill the alloy powder to prevent oxidation of the alloy powder and introduction of impurity gases during the ball milling exothermic process; and / or the morphology of the alloy powder after ball milling is roughly spherical without edges and corners.

[0023] Preferably, in the screening and mixing steps: the alloy powders of various particle sizes are added to the mixing container, and the alloy powders of various particle sizes are mixed using a vacuum airflow mixing method. At the same time, the order and amount of adding powders of different particle sizes are controlled during mixing to achieve the purpose of fully mixing powders of each level. First, the alloy powder of the third particle size is added; secondly, the alloy powder of the second particle size is slowly added; finally, the alloy powder of the first particle size is slowly added, so that the powder is mixed while being added to ensure that the powder is fully mixed and uniform. Here, the present invention strictly controls the particle size of the powder and the proportion of different particle sizes, and controls the order and amount of adding during mixing; in addition, in order to improve the bonding force and uniformity between the powders, the prior art adds a certain amount of binder to the powder, and the addition of the binder will affect the density and mechanical properties of the parts after molding, while the present invention does not need to add a binder, and through reasonable process parameter design, low-cost and excellent performance parts can be obtained.

[0024] On the other hand, an embodiment of the present invention provides a nickel-based high-temperature alloy powder, wherein the nickel-based high-temperature alloy powder is mixed by alloy powders of multiple particle sizes: preferably, the nickel-based high-temperature alloy powder is mixed by alloy powder of a first particle size, alloy powder of a second particle size, and alloy powder of a third particle size; wherein the particle size D1 of the alloy powder of the first particle size is: 10 μm<D1≤20 μm; the particle size D2 of the alloy powder of the second particle size is: 20 μm<D2≤40 μm, and the particle size D3 of the alloy powder of the third particle size is: 40 μm< D3≤50μm; wherein, the mass proportion of the first particle size grade alloy powder in the nickel-based high-temperature alloy powder is 30-35%; the mass proportion of the second particle size grade alloy powder in the nickel-based high-temperature alloy powder is 45-50%; the mass proportion of the third particle size grade alloy powder in the nickel-based high-temperature alloy powder is 20-25%; preferably, the morphology of the nickel-based high-temperature alloy powder is roughly spherical without edges and corners. Preferably, the nickel-based high-temperature alloy powder is prepared by the preparation method of the nickel-based high-temperature alloy powder described in any one of the above items.

[0025] In another aspect, an embodiment of the present invention provides a method for preparing a nickel-based high-temperature alloy part, wherein the preparation method comprises the following steps:

[0026] Step 1): using additive manufacturing technology to mold the above-mentioned nickel-based high-temperature alloy powder to obtain a nickel-based high-temperature alloy molded part;

[0027] Step 2): heat treating the nickel-based high-temperature alloy molded part to obtain a nickel-based high-temperature alloy part.

[0028] Preferably, the additive manufacturing technology uses selective laser melting technology; preferably, the process parameters of the selective laser melting technology are set as follows: laser power is 150-300W, laser scanning rate is 100-350mm / s, laser scanning spacing is 20-100μm, and powder layer thickness is 30-50μm.

[0029] Preferably, the step 2) comprises:

[0030] Solution treatment: The nickel-based high-temperature alloy molded part is subjected to solution treatment, and after cooling, a nickel-based high-temperature alloy molded part after solution treatment is obtained;

[0031] First aging treatment: performing a first aging treatment on the nickel-based high-temperature alloy molded part after the solid solution treatment, and obtaining the nickel-based high-temperature alloy molded part after the first aging treatment after cooling;

[0032] Second aging treatment: performing a second aging treatment on the nickel-based high-temperature alloy molded part after the second aging treatment, and obtaining a nickel-based high-temperature alloy part after cooling;

[0033] Preferably, the temperature of the solution treatment is 1220±10°C, and the holding time at the temperature of the solution treatment is 2±0.5h;

[0034] Preferably, the temperature of the first aging treatment is 1050±10°C, and the holding time at the temperature of the first aging treatment is 4±0.5h;

[0035] Preferably, the temperature of the second aging treatment is 840±10°C, and the holding time at the temperature of the second aging treatment is 16±0.5h;

[0036] Preferably, in the steps of solution treatment, first aging treatment and second aging treatment, the cooling method is: cooling to room temperature by passing argon gas.

[0037] On the other hand, an embodiment of the present invention provides a nickel-based high-temperature alloy part, characterized in that the nickel-based high-temperature alloy part is prepared by any of the above-mentioned methods for preparing nickel-based high-temperature alloy parts; preferably, the density of the nickel-based high-temperature alloy part is above 99.5%, and the average grain size is 30-35μm. Preferably, the size of the γ′ precipitated phase in the nickel-based high-temperature alloy part is 0.6-0.7μm, presents a nearly cubic structure, and is uniformly dispersed in the matrix.

[0038] Compared with the prior art, the nickel-based high-temperature alloy powder, nickel-based high-temperature alloy part and preparation method thereof of the present invention have at least the following beneficial effects:

[0039] The existing conventional process for the preparation of nickel-based high-temperature alloy powder is: after the raw materials are cast into alloy ingots, the nickel-based high-temperature alloy powder is obtained by vacuum gas atomization, and then the obtained powder is directly 3D printed. The nickel-based high-temperature alloy powder obtained by this process is large in size, poor in spheroidization state, and uneven in morphology, which directly affects the density and mechanical properties of the parts after forming.

[0040] Different from the prior art, the present invention provides a method for preparing a nickel-based high-temperature alloy, comprising the following steps: preparing a nickel-based high-temperature alloy master alloy ingot into an alloy powder; ball-milling the alloy powder to obtain a ball-milled alloy powder; screening the ball-milled alloy powder to screen out alloy powders of multiple particle sizes; then, mixing the alloy powders of multiple particle sizes according to the proportion and the order of adding materials to reduce the gaps between the alloy powders to obtain a nickel-based high-temperature alloy powder; in this invention, the alloy powder is ball-milled and then screened to screen out alloy powders of different particle sizes, and the alloy powder has a good morphology, and the different particle sizes are mixed in multiple levels to make the particle size distribution more reasonable, reduce the gap rate between the powders, and refine the organization. Based on the use of the powder, through the synergistic effect of optimizing multiple process parameters, uniform and dense parts with excellent mechanical properties can be obtained after forming by additive technology.

[0041] Furthermore, the alloy powders of multiple particle sizes include a first particle size grade alloy powder, a second particle size grade alloy powder, and a third particle size grade alloy powder; wherein the particle size D1 of the first particle size grade alloy powder is 10μm<D1≤20μm, the particle size D2 of the second particle size grade alloy powder is 20μm<D2≤40μm, and the particle size D3 of the third particle size grade alloy powder is 40μm<D3≤50μm; wherein the mass proportion of the first particle size grade alloy powder in the nickel-based high-temperature alloy powder is 30-35%; the mass proportion of the second particle size grade alloy powder in the nickel-based high-temperature alloy powder is 45-50%; and the mass proportion of the third particle size grade alloy powder in the nickel-based high-temperature alloy powder is 20-25%. It should be noted that if there is too much fine powder or coarse powder, a good gradation state cannot be achieved. The above-mentioned mixing scheme provided by the present invention has a continuous distribution of powders from small to large, and each level has an appropriate proportion, which belongs to continuous gradation. The gaps of coarse powder are filled with medium powder, and the gaps of medium powder are filled with fine powder. Such step-by-step filling makes the powder form the most dense stacking state, the void ratio reaches the minimum value, and the stacking density reaches the maximum value, thereby improving the density after molding. Here, the nickel-based alloy powder obtained by mixing the above-mentioned first-grade alloy powder, the second-grade alloy powder, and the third-grade alloy powder according to the above-mentioned proportion can be molded into a nickel-based high-temperature alloy part with a density of more than 99.5%, an average grain size of 30μm, and better mechanical properties.

[0042] On the other hand, an embodiment of the present invention provides a method for preparing a nickel-based high-temperature alloy part. According to the characteristics of the above-mentioned nickel-based high-temperature alloy powder, the present invention adjusts the process parameters of the selective melting, changes the solidification rate of the powder molding, reduces the tendency of the alloy to crack during the 3D printing process, improves the bonding strength and density of the parts after molding, and solves the problem that the alloy is prone to cracking during the additive manufacturing process, thereby greatly improving the mechanical properties of the parts after molding.

[0043] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 The particle size and morphology of the alloy powder after high-energy ball milling for different times. Figure 1 Figure (a) shows the particle size and morphology of the alloy powder after high-energy ball milling for 1 hour; Figure 1 Figure (b) shows the particle size and morphology of the alloy powder after high-energy ball milling for 2 hours;

[0045] Figure 2The microstructure pictures of the nickel-based high-temperature alloy parts prepared in Example 1 and Comparative Example 1 are shown respectively. Figure 2 Figure (a) is a microstructure image of the nickel-based high-temperature alloy part of Example 1 (corresponding to ratio 1); Figure 2 Figure (b) is a microstructure image of the nickel-based high-temperature alloy part of Comparative Example 1 (corresponding to ball milling for 2 hours).

[0046] Figure 3 The fracture morphology and crack distribution of the nickel-based high-temperature alloy specimens prepared in Example 1 and Comparative Example 1 after stretching. Figure 3 Figure (a) shows the fracture morphology and crack distribution of the nickel-based high-temperature alloy sample (corresponding to ratio 1) prepared in Example 1 after stretching; Figure 3 Figure (b) shows the fracture morphology and crack distribution of the nickel-based high-temperature alloy specimen prepared in Comparative Example 1 (corresponding to ball milling for 2 hours) after stretching.

[0047] Figure 4 The distribution is the size and morphology of the precipitated phase of the nickel-based high-temperature alloy sample prepared in Example 1 and Comparative Example 1 after heat treatment; wherein, Figure 4 Figure (a) is a picture of the size and morphology of the precipitated phase after heat treatment of the nickel-based high-temperature alloy sample (corresponding to ratio 1) prepared in Example 1; Figure 4 Figure (b) is a picture of the precipitated phase size and morphology of the nickel-based high-temperature alloy sample prepared in Comparative Example 1 (corresponding to ball milling for 2 hours) after heat treatment. DETAILED DESCRIPTION

[0048] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation methods, structures, features and effects of the present invention application are described in detail below in conjunction with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures, or characteristics in one or more embodiments may be combined in any suitable form.

[0049] The embodiment of the present invention mainly provides a nickel-based high-temperature alloy powder, a nickel-based high-temperature alloy part and a preparation method thereof. The inventive concept is: by screening the alloy powder after ball milling to obtain powders of different particle sizes, the powders of different particle sizes are reasonably proportioned and mixed to make their particle size distribution more reasonable, reduce the gap ratio between powders, improve the bonding strength and density of parts after molding, solve the disadvantage that the alloy is prone to cracks in the additive manufacturing process, thereby greatly improving the mechanical properties of the parts after molding.

[0050] Furthermore, the raw materials are smelted into alloy ingots, and then the atomization parameters of the vacuum air atomization method are reasonably set to obtain nickel-based high-temperature alloy powder. The obtained alloy powder is subjected to high-energy ball milling, and the appropriate grinding ball diameter and ball-to-material ratio are selected, and the ball milling time is adjusted, so as to make the nickel-based high-temperature alloy powder more refined and uniform. The powder is then sieved to obtain powders of different particle sizes, which are then mixed and the mixing ratio is adjusted to eliminate cracks generated during molding, thereby greatly improving the density and mechanical properties of the parts after molding.

[0051] The technical solution of the present invention is as follows:

[0052] On the one hand, an embodiment of the present invention provides a method for preparing a nickel-based high-temperature alloy powder, which mainly comprises the following steps:

[0053] Preparation steps of nickel-based high-temperature alloy master alloy ingot: In this step, the master alloy ingot is smelted according to the chemical composition of the alloy.

[0054] The chemical composition of the nickel-based high-temperature alloy master alloy ingot is as follows, in terms of weight percentage:

[0055] C: 0.12-0.16wt%, Cr: 8.00-9.50wt%, Co: 9.00-10.50wt%, Mo: 1.20-2.40wt%, Al: 5.10-5.70wt%, Ti: 2.00-2.90wt%, W: 9.50-11.00wt%, Nb: 0.80-1.20wt%, rare earth elements: 0.015-0.03wt%; grain boundary strengthening elements: 0.015-0.035wt%, and the balance is Ni.

[0056] Preferably, the rare earth elements include Y and Ce; wherein, in the nickel-based high-temperature alloy powder, the mass fraction of the Y element is 0.005-0.01wt%, and the mass fraction of the Ce element is 0.01-0.02wt%;

[0057] Preferably, the grain boundary strengthening element includes element B; wherein, in the nickel-based high-temperature alloy powder, the mass fraction of element B is 0.015-0.035wt%.

[0058] Among them, a small amount of Y, Ce, and B are added. Y and Ce are rare earth elements, and their purpose is to remove impurity elements such as oxygen in the alloy and improve the purity of the alloy. The B element is a grain boundary strengthening element, which can improve the stability of the grain boundary and improve the mechanical properties.

[0059] The raw materials are required to be free of gas adsorption and inclusions. The prepared main materials are loaded into the furnace in the order of cobalt, carbon, tungsten, molybdenum, niobium, chromium and nickel. Small alloy materials are added to the molten steel through the side feeding bin. After the first refining, the power is turned off and the temperature is cooled to the state of metal liquid condensation film, and small alloy materials are added. After that, the secondary refining is carried out. The order of addition is aluminum, aluminum yttrium, nickel cerium, titanium, nickel boron, etc.

[0060] After the charge is loaded, the furnace door is closed and vacuum is drawn. When the vacuum degree is less than 50Pa, power is supplied to start melting until all the charge is melted. Then the first refining treatment is carried out at a refining temperature of 1500±30℃. After the first refining, the temperature is lowered for the second low-temperature refining at a refining temperature of 1400±30℃. After the refining is completed, the power is increased to raise the temperature, and pouring is carried out after the temperature reaches 1450±30℃.

[0061] Powder making step: preparing nickel-based high-temperature alloy master alloy ingot into alloy powder.

[0062] A nickel-based high-temperature alloy master alloy is prepared into alloy powder by vacuum gas atomization.

[0063] The atomization pressure and the atomization gas temperature will affect the particle size and morphology of the powder. Preferably, the atomization pressure is 3.5 MPa and the atomization gas temperature is 100°C.

[0064] Ball milling step: ball milling the alloy powder to obtain ball milled alloy powder.

[0065] The fine and uniform alloy powder can be obtained by adjusting the ball milling parameters. The alloy powder obtained by vacuum gas atomization is subjected to high-energy ball milling to further adjust the particle size and morphology of the alloy powder. The preferred grinding ball diameter is 3-5 mm, the ball-to-material ratio is 15-17:1, and the ball milling time is 1h±0.2 and 2h±0.2h respectively.

[0066] Screening and mixing steps: The alloy powder after ball milling is screened to obtain alloy powders of different particle sizes, and then the alloy powders of different particle sizes are mixed to make the obtained parts have higher bonding strength.

[0067] Among them, in this step, the alloy powders of various particle sizes are screened out and added to the mixing container at one time, and the alloy powders of various particle sizes are mixed using the vacuum airflow mixing method. During mixing, the order and amount of adding powders of different particle sizes are controlled to achieve the purpose of fully mixing the powders of each level. First, the alloy powder of the third particle size is added; secondly, the alloy powder of the second particle size is slowly added; finally, the alloy powder of the first particle size is slowly added, so that the powder is mixed while being added to ensure that the powder is fully mixed and uniform. Using the vacuum airflow mixing method to mix the powder can effectively avoid oxidation of the powder during the mixing process, improve the purity, and thus improve the mechanical properties of the parts.

[0068] Here, the alloy powder after atomization treatment has a more uniform and non-angular morphology after ball milling, which avoids stress concentration on parts and reduces the tendency of crack initiation; the powder after ball milling is then screened and mixed, so that the powders can be better combined, the porosity is smaller, the density and performance are higher.

[0069] Specifically, the alloy powder after ball milling is sieved to screen out the first particle size grade alloy powder, the second particle size grade alloy powder and the third particle size grade alloy powder; then, the first particle size grade alloy powder, the second particle size grade alloy powder and the third particle size grade alloy powder are mixed to obtain the nickel-based high temperature alloy powder.

[0070] Among them, the particle size D1 of the first particle size grade alloy powder is: 10μm<D1≤20μm, and preferably, the mass proportion of the first particle size grade alloy powder in the nickel-based high-temperature alloy powder is 30-35%; the particle size D2 of the second particle size grade alloy powder is: 20μm<D2≤40μm, and preferably, the mass proportion of the second particle size grade alloy powder in the nickel-based high-temperature alloy powder is 45-50%; the particle size D3 of the third particle size grade alloy powder is: 40μm<D3≤50μm, and preferably, the mass proportion of the third particle size grade alloy powder in the nickel-based high-temperature alloy powder is 20-25%. It should be noted here that if there is too much fine powder or coarse powder, a good gradation state cannot be achieved. In the above mixing scheme provided by the present invention, the powders are continuously distributed from small to large, and each level occupies an appropriate proportion, which belongs to continuous gradation. The gaps in the coarse powder are filled with medium powder, and the gaps in the medium powder are filled with fine powder. Such step-by-step filling makes the powder form the most dense stacking state, the void ratio reaches the minimum value, the stacking density reaches the maximum value, and the density after molding is improved.

[0071] On the other hand, an embodiment of the present invention provides a nickel-based high-temperature alloy part, which mainly includes the following steps:

[0072] Step 1): The nickel-based high-temperature alloy powder is molded by using additive manufacturing technology to obtain a nickel-based high-temperature alloy molded part.

[0073] Here, the additive manufacturing technology uses the selective laser melting technology; preferably, the process parameters of the selective laser melting technology are set as follows: laser power is 150-300W, laser scanning rate is 100-350mm / s, laser scanning spacing is 20-100μm, and powder layer thickness is 30-50μm. Among them, the laser power used here is more matched with the powder particle size. At this power, most powders of different particle sizes can be melted quickly. At the same time, the thickness of the powder layer is similar to the average particle size of the powder, which reduces the heat affected zone during scanning and is conducive to improving density and bonding strength.

[0074] Step 2): heat treating the nickel-based high-temperature alloy molded part to obtain a nickel-based high-temperature alloy part.

[0075] The nickel-based high-temperature alloy formed parts are subjected to solution treatment, first aging treatment and second aging treatment in sequence, wherein the temperature of the solution treatment is 1220±10℃, kept warm for 2h, and cooled to room temperature by argon gas; the temperature of the first aging treatment is 1050±10℃, kept warm for 4h, cooled to room temperature by argon gas, and the temperature of the second aging treatment is 840±10℃, kept warm for 16h, and cooled to room temperature by argon gas.

[0076] The present invention is further described below by specific examples and comparative examples:

[0077] Example 1

[0078] This embodiment prepares a nickel-based high-temperature alloy powder and a nickel-based high-temperature alloy part, and the main preparation steps are as follows:

[0079] Preparation steps of nickel-based high-temperature alloy master alloy ingot: first, use high-Al dry vibration material to pound the crucible into shape, and carry out pure nickel sintering and furnace washing treatment, weigh the materials according to the requirements of the batching list, use qualified platform scales, balances and other equipment, and the error between the actual addition amount and the calculated addition amount should not exceed ±2%. Since the higher the C element content, the greater the tendency of cracks, the C content here takes the lower limit of the component requirements. In terms of weight percentage, C: 0.12wt%, Cr: 9.00wt%, Co: 10.00wt%, Mo: 2.00wt%, Al: 5.70wt%, Ti: 2.70wt%, W: 10.00wt%, Nb: 1.00wt%, Y: 0.005wt%, Ce: 0.01wt%, B: 0.02wt%, and the balance is Ni. The raw materials are required to have no gas adsorption, no inclusions, etc. The prepared main materials are loaded into the furnace, and the order of distribution is cobalt, carbon, tungsten, molybdenum, niobium, chromium, and nickel. Small alloy materials are added into the molten steel through the side feeding bin, and the order of addition is aluminum, aluminum yttrium, nickel cerium, titanium, nickel boron, etc.

[0080] After the main material is loaded into the furnace, the furnace door is closed and vacuum is drawn. When the vacuum degree is less than 50Pa, power is supplied to start melting until all the charge is melted. Then the first refining treatment is carried out at a refining temperature of 1500℃. After the first refining, the power is turned off and the temperature is lowered to a condensed film state of the metal liquid. Small alloy materials are added to the alloy liquid through the side feeding bin and then the second low-temperature refining is carried out at a refining temperature of 1400℃. After the refining is completed, the power is increased to raise the temperature, and pouring is carried out after the temperature reaches 1450℃.

[0081] Powder making step: The smelted alloy ingot is subjected to vacuum atomization treatment. The atomization pressure and the atomization gas temperature will affect the particle size and morphology of the powder. Within a certain range, the greater the atomization pressure, the smaller the obtained powder. However, excessive atomization pressure will lead to poor powder spheroidization. Therefore, in this embodiment, the atomization pressure is selected to be 3.5 MPa and the atomization gas temperature is selected to be 100°C.

[0082] In this embodiment, the particle size of the atomized alloy powder is 7-68 μm, and the alloy morphology is an irregular spherical shape with edges and corners.

[0083] Ball milling step: In order to further improve the particle size and spheroidization degree of the nickel-based high-temperature alloy powder, the powder obtained by vacuum atomization is subjected to high-energy ball milling. The alloy powder is ball milled using a planetary vacuum ball mill to prevent the alloy powder from being oxidized and introducing impurity gases during the exothermic process of ball milling. In addition, a ball milling time that is too short will have little effect on the particle size of the alloy powder. If the ball milling time is too long, cold welding of the powder will occur during the ball milling process, causing the powder size to become larger and the degree of spheroidization to decrease. Therefore, the ball milling parameters in this embodiment are set as follows: the rotation speed of the planetary ball mill is 280r / min, the ball-to-material ratio is 15:1, the grinding ball diameter is 5mm, and the ball milling time is 2h. Among them, the particle size and morphology of the alloy powder after high-energy ball milling for 2h are shown in FIG. Figure 1 As shown in FIG. 5( b ), the particle size of the alloy powder after ball milling is 5-60 μm, and the morphology of the alloy powder is roughly spherical without edges and corners.

[0084] Screening and mixing steps: Screen the alloy powder after ball milling to screen out the first particle size alloy powder (greater than 10μm, less than or equal to 20μm), the second particle size alloy powder (greater than 20μm, less than or equal to 40μm), and the third particle size alloy powder (greater than 40μm, less than or equal to 50μm), and mix the screened powders (using vacuum airflow mixing method for mixing). When mixing, control the order and amount of adding powders of different particle sizes to achieve the purpose of fully mixing powders of each level. First, add the third particle size alloy powder; secondly, slowly add the second particle size alloy powder; finally, slowly add the first particle size alloy powder, so that the powder is added and mixed at the same time to ensure that the powder is fully mixed and uniform. The mixing ratio is shown in Table 1.

[0085] Table 1 Different ratios of alloy powders

[0086] Particle size / μm Ratio 1 Ratio 2 Ratio 3 Ratio 4 Greater than 10, less than or equal to 20 30％ 80％ 10％ 10％ Greater than 20, less than or equal to 40 50％ 10％ 80％ 10％ Greater than 40, less than or equal to 50 20％ 10％ 10％ 80％

[0087] According to Table 1, four kinds of nickel-based high-temperature alloy powders are prepared in this embodiment: a first nickel-based high-temperature alloy powder (corresponding to ratio 1), a second nickel-based high-temperature alloy powder (corresponding to ratio 2), a third nickel-based high-temperature alloy powder (corresponding to ratio 3), and a fourth nickel-based high-temperature alloy powder (corresponding to ratio 4).

[0088] The four nickel-based high-temperature alloy powders were subjected to selective laser melting to obtain four nickel-based high-temperature alloy parts, wherein the laser power was 300 W, the laser scanning rate was 200 mm / s, the laser scanning interval was 30 μm, and the powder layer thickness was 50 μm.

[0089] Four nickel-based high-temperature alloy parts were heat treated. Specifically, the heat treatment was carried out in a vacuum heat treatment furnace, with a solution treatment temperature of 1220℃±10℃, kept at this temperature for 2 hours, and cooled to room temperature through argon gas; the first aging temperature was 1050℃±10℃, kept at this temperature for 4 hours, cooled to room temperature through argon gas, and the second aging temperature was 840℃±10℃, kept at this temperature for 16 hours, and cooled to room temperature through argon gas.

[0090] The density and mechanical properties of the four nickel-based superalloy samples were tested respectively. It was found that the nickel-based superalloy sample with the corresponding ratio 1 had the best density, which could reach more than 99.5%, and the average grain size could reach 30μm (see Figure 2 (a) in the microstructure); at the same time, the size of the γ′ precipitate in the alloy after heat treatment is 0.6-0.7μm, showing a nearly cubic structure, and is evenly dispersed in the entire matrix. Due to the small size of the precipitate, the precipitation strengthening effect is better (such as Figure 4 As shown in Figure (a) above, its mechanical properties are also the highest, with a yield strength of 1200MPa and a tensile strength of 1346MPa at 800°C.

[0091] In addition, the yield strength of the nickel-based high-temperature alloy samples of Ratio 2, Ratio 3, and Ratio 4 is between 1090-1124MPa, and the tensile strength is between 1200-1230MPa, which are all inferior to the performance of the nickel-based high-temperature alloy sample corresponding to Ratio 1. This is because the ratios of Ratios 2-4 are unreasonable, and their performance is worse than the control example.

[0092] Example 2

[0093] This embodiment prepares a nickel-based high-temperature alloy powder and a nickel-based high-temperature alloy part, which is different from the embodiment 1 in that: in the screening and mixing steps, the alloy powder ratio is shown in Table 2. Other steps and parameters are consistent with the embodiment 1.

[0094] After testing, the nickel-based high-temperature alloy prepared in this embodiment has a yield strength of 1185 MPa and a tensile strength of 1322 MPa.

[0095] Table 2 Different ratios of alloy powders

[0096] Particle size / μm Ratio Greater than 10, less than or equal to 20 30％ Greater than 20, less than or equal to 40 45％ Greater than 40, less than or equal to 50 25％

[0097] Example 3

[0098] This embodiment prepares a nickel-based high-temperature alloy powder and a nickel-based high-temperature alloy part, which is different from the embodiment 1 in that: in the screening and mixing steps, the alloy powder ratio is shown in Table 3. The other steps and parameters are consistent with the embodiment 1.

[0099] After testing, the nickel-based high-temperature alloy prepared in this embodiment has a yield strength of 1179 MPa and a tensile strength of 1321 MPa.

[0100] Table 3 Different ratios of alloy powder

[0101] Particle size / μm Ratio Greater than 10, less than or equal to 20 35％ Greater than 20, less than or equal to 40 45％ Greater than 40, less than or equal to 50 20％

[0102] Comparative Example 1

[0103] Comparative Example 1 A nickel-based high-temperature alloy powder and a nickel-based high-temperature alloy part are prepared, mainly comprising the following steps:

[0104] Preparation steps of nickel-based high-temperature alloy master alloy ingot: firstly, use high-Al dry vibration material to pound the crucible into shape, and carry out pure nickel sintering and furnace washing treatment, weigh the materials according to the requirements of the batching list, use qualified platform scales, balances and other equipment, and the error between the actual addition amount and the calculated addition amount should not exceed ±2%. In terms of weight percentage, C: 0.12wt%, Cr: 9.00wt%, Co: 10.00wt%, Mo: 2.00wt%, Al: 5.70wt%, Ti: 2.70wt%, W: 10.00wt%, Nb: 1.00wt%, Y: 0.005wt%, Ce: 0.01wt%, B: 0.02wt%, and the balance is Ni. The raw materials are required to have no gas adsorption, no inclusions, etc. The prepared main materials are loaded into the furnace, and the order of distribution is cobalt, carbon, tungsten, molybdenum, niobium, chromium, and nickel. Small alloy materials are added into the molten steel through the side feeding bin, and the order of addition is aluminum, aluminum yttrium, nickel cerium, titanium, nickel boron, etc.

[0105] After the charge is loaded, the furnace door is closed and vacuum is drawn. When the vacuum degree is less than 50Pa, power is supplied to start melting until all the charge is melted. Then the first refining treatment is carried out at a refining temperature of 1500℃±30℃. After the first refining, the power is turned off and the temperature is lowered to a condensed film state of the metal liquid. After adding small alloy materials into the alloy liquid through the side feeding bin, the second low-temperature refining is carried out at a refining temperature of 1400℃±30℃. After the refining is completed, the power is increased to raise the temperature, and pouring is carried out after the temperature reaches 1450℃±30℃.

[0106] Powder making step: The smelted alloy ingot is subjected to vacuum atomization treatment. The atomization pressure and atomization gas temperature will affect the particle size and morphology of the powder. Within a certain range, the greater the atomization pressure, the smaller the obtained powder. However, excessive atomization pressure will lead to poor spheroidization of the powder. Therefore, in this embodiment, the atomization pressure is selected as 3.5MPa and the atomization gas temperature is selected as 100°C. In this embodiment, the particle size of the atomized alloy powder is 7-68μm, and the alloy morphology is an irregular sphere with edges and corners.

[0107] Ball milling step: In order to further improve the particle size and spheroidization degree of the nickel-based high-temperature alloy powder, the powder obtained by vacuum atomization is subjected to high-energy ball milling treatment. If the ball milling time is too short, the particle size of the alloy powder will not be significantly affected. If the ball milling time is too long, the powder will be cold welded during the ball milling process, resulting in the size of the powder becoming larger and the degree of spheroidization being reduced. Therefore, the ball milling parameters in this embodiment are set as follows: the rotation speed of the planetary ball mill is 280r / min, the ball-to-material ratio is 15:1, the grinding ball diameter is 5mm, and the ball milling time is 1h and 2h respectively, to obtain two types of nickel-based high-temperature alloy powders: nickel-based high-temperature alloy powder after ball milling for 1h) and nickel-based high-temperature alloy powder after ball milling for 2h. Among them, the particle size and morphology of the alloy powder after high-energy ball milling for 1h can be found in Figure 1 As shown in Figure (a) in the figure; the particle size and morphology of the alloy powder after high-energy ball milling for 2 hours refer to Figure 1 As shown in Figure (b) in the figure. Figure 1 From Figures (a) and (b), we can see that the ball milling time has a great influence on the morphology and coarseness of the powder.

[0108] The two nickel-based high-temperature alloy powders were subjected to selective laser melting to obtain two nickel-based high-temperature alloy molded parts; wherein the laser power was 300 W, the laser scanning rate was 200 mm / s, the laser scanning interval was 30 μm, and the powder layer thickness was 50 μm.

[0109] The two nickel-based high-temperature alloy parts were heat treated to obtain two nickel-based high-temperature alloy parts. The heat treatment was carried out in a vacuum heat treatment furnace, with a solution treatment temperature of 1220℃±10℃, kept for 2 hours, and cooled to room temperature through argon; the first aging temperature was 1050℃±10℃, kept for 4 hours, cooled to room temperature through argon, and the second aging temperature was 840℃±10℃, kept for 16 hours, and cooled to room temperature through argon.

[0110] The performance of the two nickel-based high-temperature alloy samples obtained after heat treatment was tested. The results showed that at 800°C, the yield strength of the first nickel-based high-temperature alloy (corresponding to ball milling for 1h) and the second nickel-based high-temperature alloy (corresponding to ball milling for 2h) were 1106MPa and 1135MPa, respectively, and the tensile strength was 1227MPa and 1260MPa, respectively. It can be seen that the strength of the second nickel-based high-temperature alloy (corresponding to ball milling for 2h) is slightly higher than that of the first nickel-based high-temperature alloy (corresponding to ball milling for 1h), but both are inferior to the mechanical properties of the embodiment of the present invention after mixing.

[0111] Figure 2 The microstructure pictures of the nickel-based high-temperature alloy parts prepared in Example 1 and Comparative Example 1 are shown respectively. Figure 2 Figure (a) is a microstructure image of the nickel-based high-temperature alloy part (corresponding to ratio 1) of Example 1 (the average grain size is 30 μm); Figure 2 Figure (b) is a microstructure image (average grain size is 50 μm) of the nickel-based high-temperature alloy part (corresponding to ball milling for 2 hours) of Comparative Example 1. It can be seen that the nickel-based high-temperature alloy part prepared in Example 1 has a smaller average grain size and is more dense.

[0112] Figure 3 The fracture morphology and crack distribution of the nickel-based high-temperature alloy specimens prepared in Example 1 and Comparative Example 1 after stretching. Figure 3 Figure (a) shows the fracture morphology and crack distribution of the nickel-based high-temperature alloy sample (corresponding to ratio 1) prepared in Example 1 after stretching; Figure 3 Figure (b) shows the fracture morphology and crack distribution of the nickel-based high-temperature alloy sample (corresponding to ball milling for 2 hours) prepared in Comparative Example 1 after stretching. It can be seen that compared with the nickel-based high-temperature alloy sample (corresponding to ratio 1) of Example 1, the cracks on the nickel-based high-temperature alloy sample (corresponding to ball milling for 2 hours) prepared in Comparative Example 1 are significantly wider and longer.

[0113] See also Figure 4 As shown in (b), the precipitated phase size of the nickel-based high-temperature alloy sample prepared in Comparative Example 1 (corresponding to ball milling for 2h) is between 1-1.5μm, with poor cubicity, and is distributed throughout the matrix.

[0114] Comparative Example 2

[0115] Comparative Example 2 A nickel-based high-temperature alloy powder and a nickel-based high-temperature alloy part are prepared, and the alloy after vacuum atomization is not subjected to ball milling treatment, but directly subjected to mixing treatment, which mainly includes the following steps:

[0116] Preparation steps of nickel-based high-temperature alloy master alloy ingot: firstly, use high-Al dry vibration material to pound the crucible into shape, and carry out pure nickel sintering and furnace washing treatment, weigh the materials according to the requirements of the batching list, use qualified platform scales, balances and other equipment, and the error between the actual addition amount and the calculated addition amount should not exceed ±2%. In terms of weight percentage, C: 0.12wt%, Cr: 9.00wt%, Co: 10.00wt%, Mo: 2.00wt%, Al: 5.70wt%, Ti: 2.70wt%, W: 10.00wt%, Nb: 1.00wt%, Y: 0.005wt%, Ce: 0.01wt%, B: 0.02wt%, and the balance is Ni. The raw materials are required to have no gas adsorption, no inclusions, etc. The prepared main materials are loaded into the furnace, and the order of distribution is cobalt, carbon, tungsten, molybdenum, niobium, chromium, and nickel. Small alloy materials are added into the molten steel through the side feeding bin, and the order of addition is aluminum, aluminum yttrium, nickel cerium, titanium, nickel boron, etc.

[0117] After the main material is loaded into the furnace, the furnace door is closed and vacuum is drawn. When the vacuum degree is less than 50Pa, power is supplied to start melting until all the charge is melted. Then the first refining treatment is carried out at a refining temperature of 1500℃±30℃. After the first refining is completed, power is turned off and the temperature is lowered to a condensed film state of the metal liquid. Small alloy materials are added to the alloy liquid through the side feeding bin and then the second low-temperature refining is carried out at a refining temperature of 1400℃±30℃. After the refining is completed, the power is increased to raise the temperature, and pouring is carried out after the temperature reaches 1450℃±30℃.

[0118] Powder making step: The smelted alloy ingot is subjected to vacuum atomization treatment. The atomization pressure and the atomization gas temperature will affect the particle size and morphology of the powder. Within a certain range, the greater the atomization pressure, the smaller the obtained powder. However, excessive atomization pressure will lead to poor powder spheroidization. Therefore, in this embodiment, the atomization pressure is selected to be 3.5 MPa and the atomization gas temperature is selected to be 100°C.

[0119] In this embodiment, the particle size of the atomized alloy powder is 7-68 μm, and the alloy morphology is an irregular spherical shape with edges and corners.

[0120] Screening and mixing steps: The powder obtained by vacuum atomization is screened to screen out a first-grade alloy powder (greater than 10 μm and less than or equal to 20 μm), a second-grade alloy powder (greater than 20 μm and less than or equal to 40 μm), and a third-grade alloy powder (greater than 40 μm and less than or equal to 50 μm), and the screened powders are mixed (mixed by vacuum airflow mixing method), and the mixing ratio is carried out according to Ratio 1 in Table 1.

[0121] The two nickel-based high-temperature alloy powders were subjected to selective laser melting to obtain two nickel-based high-temperature alloy molded parts; wherein the laser power was 300 W, the laser scanning rate was 2 mm / s, the laser scanning interval was 30 μm, and the powder layer thickness was 50 μm.

[0122] The nickel-based high-temperature alloy molded parts are heat treated to obtain nickel-based high-temperature alloy parts. The heat treatment is carried out in a vacuum heat treatment furnace, the solution treatment temperature is 1220℃±10℃, the temperature is kept for 2 hours, and the argon gas is passed to cool to room temperature; the first aging temperature is 1050℃±10℃, the temperature is kept for 4 hours, the argon gas is passed to cool to room temperature, and the second aging temperature is 840℃±10℃, the temperature is kept for 16 hours, and the argon gas is passed to cool to room temperature.

[0123] The performance of the nickel-based high-temperature alloy specimens after heat treatment was tested. The results showed that at 800°C, the yield strength was 1161MPa and the tensile strength was 1301MPa.

[0124] By comparing the above examples with the comparative examples, it can be seen that the "ball milling treatment" and "screening and mixing treatment" of the vacuum atomized alloy powder have a synergistic effect on the additive manufacturing technology, and the two work together to improve the mechanical properties of nickel-based high-temperature alloy parts. Furthermore, how to mix (i.e. what kind of particle size alloy powder is screened and in what proportion) is also crucial to improving the performance of the alloy. If the mixing is unreasonable, the mechanical properties of the alloy will not be greatly improved.

[0125] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a nickel-based high-temperature alloy powder, characterized in that: It includes the following steps: Powder making step: preparing nickel-based high-temperature alloy master alloy ingot into alloy powder; Ball milling step: ball milling the alloy powder to obtain the alloy powder after ball milling; wherein the particle size of the alloy powder after ball milling is 5-60 μm; Screening and mixing step: Screening the alloy powder after ball milling to screen out alloy powders of various particle sizes; then, mixing the alloy powders of various particle sizes to reduce the gaps between the alloy powders to obtain nickel-based high-temperature alloy powder.

2. The method for preparing nickel-based high-temperature alloy powder according to claim 1, characterized in that: The alloy powder includes a first-size alloy powder, a second-size alloy powder, and a third-size alloy powder; wherein, The particle size D1 of the first particle size grade alloy powder is: 10 μm<D1≤20 μm; The particle size D2 of the second particle size grade alloy powder is: 20 μm<D2≤40 μm; The particle size D3 of the third particle size grade alloy powder is: 40 μm<D3≤50 μm; Preferably, the mass proportion of the first particle size grade alloy powder in the nickel-based high-temperature alloy powder is 30-35%; the mass proportion of the second particle size grade alloy powder in the nickel-based high-temperature alloy powder is 45-50%; the mass proportion of the third particle size grade alloy powder in the nickel-based high-temperature alloy powder is 20-25%; Preferably, the particle size D1 of the first size grade alloy powder and the particle size D2 of the second size grade alloy powder need to satisfy the following relationship:

3. The method for preparing nickel-based high-temperature alloy powder according to claim 1, characterized in that: The chemical composition of the nickel-based high-temperature alloy powder is as follows, in terms of weight percentage: C: 0.12-0.16wt%, Cr: 8.00-9.50wt%, Co: 9.00-10.50wt%, Mo: 1.20-2.40wt%, Al: 5.10-5.70wt%, Ti: 2.00-2.90wt%, W: 9.50-11.00wt%, Nb: 0.80-1.20wt%, rare earth elements: 0.015-0.03wt%; grain boundary strengthening elements: 0.015-0.035wt%, the balance is Ni; Preferably, the rare earth elements include Y and Ce; wherein, in the nickel-based high-temperature alloy powder, the mass fraction of the Y element is 0.005-0.01wt%, and the mass fraction of the Ce element is 0.01-0.02wt%; Preferably, the grain boundary strengthening element includes element B; wherein, in the nickel-based high-temperature alloy powder, the mass fraction of element B is 0.015-0.035wt%.

4. The method for preparing nickel-based high-temperature alloy powder according to any one of claims 1 to 3, characterized in that: The preparation steps of the nickel-based high-temperature alloy master alloy ingot are as follows: According to the chemical composition, the first raw material is charged into the furnace and vacuumed. When the vacuum degree is less than 50Pa, power is supplied to start melting until the first raw material is completely melted; then the first refining treatment is performed; after the first refining treatment, the power is turned off and the temperature is lowered to a metal liquid condensation film state, and the second raw material is added to the alloy liquid through a side feeding bin, and then the second refining treatment is performed; after the second refining treatment is completed, the temperature is raised to a pouring temperature for pouring to obtain a nickel-based high-temperature alloy master alloy ingot; Preferably, the order of charging the first raw materials into the furnace is: cobalt, carbon, tungsten, molybdenum, niobium, chromium, nickel; Preferably, the second raw material is added in the following order: aluminum, aluminum yttrium, nickel cerium, titanium, nickel boron; Preferably, the temperature of the first refining treatment is 1500±30°C, and the time of the first refining treatment is 50±10min; Preferably, the temperature of the second refining treatment is 1400±30°C, and the time of the second refining treatment is 50±10min; Preferably, the pouring temperature is 1450±30°C.

5. The method for preparing nickel-based high-temperature alloy powder according to any one of claims 1 to 4, characterized in that: In the milling step: A nickel-based high-temperature alloy master alloy ingot is made into alloy powder by vacuum gas atomization method; Preferably, the particle size of the alloy powder is 7-68 μm; Preferably, the alloy powder has an irregular spherical shape with edges and corners; Preferably, the atomization pressure is 3.5±0.5 MPa and the atomization gas temperature is 100±10°C.

6. The method for preparing nickel-based high-temperature alloy powder according to any one of claims 1 to 5, characterized in that: In the ball milling step: The diameter of the grinding balls is 3-5 mm, the ball-to-material ratio is (15-17):1, the ball milling time is 2±0.2 h, and the rotation speed is 280±20 r / min; and / or The alloy powder is ball-milled using a planetary vacuum ball mill to prevent oxidation of the alloy powder and introduction of impurity gases during the exothermic process of ball milling; and / or The alloy powder after ball milling is roughly spherical without edges and corners.

7. The method for preparing nickel-based high-temperature alloy powder according to any one of claims 1 to 6, characterized in that: In the screening and mixing steps: The alloy powders of various particle sizes screened out are added into a mixing container, and the alloy powders of various particle sizes are mixed by using a vacuum air flow mixing method; Preferably, during mixing, the third size grade alloy powder is added first; secondly, the second size grade alloy powder is gradually added; finally, the first size grade alloy powder is gradually added, and the powders are mixed while being added so that the powders are fully mixed.

8. A nickel-based high-temperature alloy powder, characterized in that: The nickel-based high-temperature alloy powder is prepared by mixing alloy powders of various particle sizes: Preferably, the nickel-based high-temperature alloy powder is mixed by a first-size alloy powder, a second-size alloy powder and a third-size alloy powder; wherein the particle size D1 of the first-size alloy powder is: 10 μm<D1≤20 μm; the particle size D2 of the second-size alloy powder is: 20 μm<D2≤40 μm; and the particle size D3 of the third-size alloy powder is: 40 μm<D3≤50 μm; The first particle size grade alloy powder accounts for 30-35% by mass in the nickel-based high-temperature alloy powder; the second particle size grade alloy powder accounts for 45-50% by mass in the nickel-based high-temperature alloy powder; the third particle size grade alloy powder accounts for 20-25% by mass in the nickel-based high-temperature alloy powder; Preferably, the nickel-based high-temperature alloy powder has a substantially spherical shape without edges and corners; Preferably, the nickel-based high-temperature alloy powder is prepared by the method for preparing the nickel-based high-temperature alloy powder according to any one of claims 1-7.

9. A method for preparing a nickel-based high-temperature alloy part, characterized in that: The preparation method comprises the following steps: Step 1): using additive manufacturing technology to mold the nickel-based high-temperature alloy powder according to claim 8 to obtain a nickel-based high-temperature alloy molded part; Step 2): heat treating the nickel-based high-temperature alloy molded part to obtain a nickel-based high-temperature alloy part.

10. The method for preparing a nickel-based high-temperature alloy part according to claim 9, characterized in that: The additive manufacturing technology uses selective laser melting technology; Preferably, the process parameters of the selective laser melting technology are set as follows: laser power is 150-300 W, laser scanning rate is 100-350 mm / s, laser scanning spacing is 20-100 μm, and powder layer thickness is 30-50 μm.

11. The method for preparing a nickel-based high-temperature alloy part according to claim 9 or 10, characterized in that: The step 2) comprises: Solution treatment: The nickel-based high-temperature alloy molded part is subjected to solution treatment, and after cooling, a nickel-based high-temperature alloy molded part after solution treatment is obtained; First aging treatment: performing a first aging treatment on the nickel-based high-temperature alloy molded part after the solid solution treatment, and obtaining the nickel-based high-temperature alloy molded part after the first aging treatment after cooling; Second aging treatment: performing a second aging treatment on the nickel-based high-temperature alloy molded part after the second aging treatment, and obtaining a nickel-based high-temperature alloy part after cooling; Preferably, the temperature of the solution treatment is 1220±10°C, and the holding time at the temperature of the solution treatment is 2±0.5h; Preferably, the temperature of the first aging treatment is 1050±10°C, and the holding time at the temperature of the first aging treatment is 4±0.5h; Preferably, the temperature of the second aging treatment is 840±10°C, and the holding time at the temperature of the second aging treatment is 16±0.5h; Preferably, in the steps of solution treatment, first aging treatment and second aging treatment, the cooling method is: cooling to room temperature by passing argon gas.

12. A nickel-based high-temperature alloy part, characterized in that: The nickel-based high-temperature alloy part is prepared by the method for preparing a nickel-based high-temperature alloy part according to any one of claims 8 to 11; Preferably, the density of the nickel-based high-temperature alloy part is above 99.5% and the average grain size is 30-35 μm; Preferably, the size of the γ′ precipitated phase in the nickel-based high-temperature alloy part is 0.6-0.7 μm, presents a nearly cubic structure, and is uniformly dispersed in the matrix.

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