A nickel-based alloy and a preparation method and application thereof

Abstract

The application discloses a nickel-based alloy and a preparation method and application thereof. The preparation method of the nickel-based alloy comprises the following steps: sequentially performing laser selective melting forming treatment and heat treatment on a nickel-based alloy raw material, and the heat treatment comprises first heat treatment, second heat treatment, third heat treatment and fourth heat treatment. According to the preparation method of the nickel-based alloy, the process parameters in the steps of laser selective melting forming and heat treatment are optimized, so that the Hastelloy X alloy containing fine dispersed intracrystalline carbide and continuous thin film-shaped carbide at a grain boundary can be obtained, and the high-temperature mechanical properties and medium-temperature enduring properties of the laser selective melting forming Hastelloy X alloy are effectively improved.

Description

Technical Field

[0001] This invention relates to the field of metal additive manufacturing technology, specifically to a nickel-based alloy, its preparation method, and its application. Background Technology

[0002] Hastelloy X alloy (domestic designations GH3536, K536) is a solid solution strengthened nickel-based superalloy with excellent corrosion resistance and oxidation resistance. This alloy exhibits good high-temperature performance, allowing for long-term use below 900℃, and is primarily used in the manufacture of aero-engine blades, combustion chamber components, and other high-temperature parts. Selective Laser Melting (SLM) technology utilizes a high-energy laser beam to scan and melt pre-placed powder in a powder bed layer by layer, enabling the direct fabrication of near-net-shape parts from a three-dimensional digital model. This technology offers advantages such as low forming constraints, high precision, and low surface roughness, and has been gradually applied in the manufacturing of components with complex shapes or internal cavity structures. Domestic and international companies have begun to use selective laser melting to produce Hastelloy X nickel-based superalloy products in large quantities.

[0003] Selective laser melting (SLM) differs significantly from forging and casting processes, primarily in the following aspects: The molten pool in SLM is small (100–300 μm), with a large temperature gradient and extremely rapid solidification. The temperature gradient roughly follows the deposition direction; when the laser beam scans the powder layer, it remelts the tops of the previously solidified columnar crystals. The unmelted portions of these columnar crystals become nuclei for directional solidification in that layer, allowing the original columnar grains from the previous layer to continue epitaxial growth along the deposition direction. During the forming process, the layer-by-layer deposition leads to rapid and repeated heating of the molten pool, resulting in high residual stress. These characteristics cause significant differences between the microstructure formed by SLM and traditional casting and forging. Therefore, heat treatment regimes suitable for casting and forging of Hastelloy X alloys may not be suitable for Hastelloy X alloys manufactured using selective laser melting.

[0004] Chinese patent CN 111390180 A describes an optimized heat treatment process that ensures the high-temperature creep performance (815℃) of SLM-formed GH3536 alloy meets forging requirements. However, for polycrystalline alloys, the characteristics of grain boundaries and intragranular precipitates have varying effects on the alloy's mechanical properties at different service temperatures. The temperature at which intragranular strength equals grain boundary strength is typically called the equal-strength temperature. Above this temperature, grain boundary strength is lower than intragranular strength, making grain boundaries a weak point; below this temperature, grain boundary strength is higher than intragranular strength, requiring control of intragranular precipitates to improve intragranular strength. Therefore, for different service temperatures of the alloy, it is necessary to develop microstructure control methods based on the characteristics of laser selective melting forming (SLM) to achieve suitable intragranular and grain boundary strengths.

[0005] Currently, engineers are primarily focusing on the high-temperature performance of SLM-formed Hastelloy X alloys. For example, they are optimizing heat treatment processes to improve creep rupture performance at 815°C. Furthermore, related research indicates that fracture above 800°C is mainly intergranular fracture, meaning that grain boundaries are weak points at this temperature. For Hastelloy X alloy components such as aero-engine combustion chamber nozzles and exhaust nozzles, which operate at long-term temperatures in the range of 600°C to 700°C, the mechanical properties (such as creep rupture performance) at this temperature are particularly critical to the reliability of the components.

[0006] As mentioned earlier, for polycrystalline alloys, the characteristics of grain boundaries and intragranular precipitates have different effects on the mechanical properties of the alloy at different service temperatures, and the control strategies for intragranular and grain boundary properties differ significantly above and below the isothermal temperature. At relatively low temperatures, such as in the range of 600℃ to 700℃, the characteristics of grain boundary strength and intragranular strength differ from those at high temperatures. That is, heat treatment regimes optimized for high-temperature creep performance may not be suitable for the performance requirements of medium-temperature service environments. Therefore, for components operating in medium-temperature environments, it is necessary to develop forming and heat treatment processes for these temperatures to extend their service life and improve creep performance. Summary of the Invention

[0007] The technical problem to be solved by this invention is to overcome the shortcomings of existing nickel-based alloys, such as poor high-temperature mechanical properties, unsuitability for temperatures of 600–700°C, and poor mid-temperature creep rupture performance. This invention provides a nickel-based alloy, its preparation method, and its applications. The preparation method of this invention optimizes the process parameters in the laser selective melting and heat treatment steps to obtain a Hastelloy X alloy containing finely dispersed, continuous, thin-film carbides at grain boundaries, effectively improving the high-temperature mechanical properties and mid-temperature creep rupture performance of the laser selective melting Hastelloy X alloy.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] One of the technical solutions provided by this invention is: a method for preparing a nickel-based alloy, comprising the following steps: sequentially subjecting the nickel-based alloy raw material to laser selective melting forming treatment and heat treatment;

[0010] The heat treatment includes a first heat treatment, a second heat treatment, a third heat treatment, and a fourth heat treatment;

[0011] The heating temperature of the first heat treatment is 1160-1180℃, and the heating time is maintained at the heating temperature for 0.9-1.1 hours; after maintaining the heating temperature of the first heat treatment for 0.9-1.1 hours, cooling is performed; the cooling temperature is below 400℃.

[0012] The second heat treatment is carried out at a heating temperature of 1165-1185℃ for 1.9-2.1 hours; the pressure at which the heating temperature is maintained is 160 MPa; after maintaining the second heat treatment at the heating temperature for 1.9-2.1 hours, cooling is performed; the cooling temperature is below 400℃.

[0013] The heating temperature of the third heat treatment is 1165-1185℃, and the heating time is maintained at the heating temperature for 0.9-1.1 hours; after maintaining the heating temperature of the third heat treatment for 0.9-1.1 hours, cooling is performed; the cooling temperature is 30-40℃.

[0014] The heating temperature of the fourth heat treatment is 750-770℃, and the heating time is maintained at the heating temperature for 0.4-0.6h; after maintaining the heating temperature of the fourth heat treatment for 0.4-0.6h, cooling is performed; the cooling temperature is 30-40℃.

[0015] In this invention, the nickel-based alloy raw material can be a conventional alloy powder in the art, generally including Cr, Co, Nb, Ti, Al, Ta, Ni, and B. The average particle size of the alloy powder can be conventional in the art, for example, 15–45 μm.

[0016] In this invention, during the laser selective melting and forming process, the laser power is 245-260W, preferably 250-255W. The spot diameter is 0.1mm. The scanning speed is 950-1150mm / s, preferably 1000-1100mm / s, for example, 1050mm / s. The scanning spacing can be 0.09-0.1mm. The powder layer thickness can be 0.04mm.

[0017] In this invention, the laser selective melting forming can generally be performed in an argon atmosphere. The purity of the argon gas in the argon atmosphere can be above 99.99 wt%.

[0018] In the laser selective melting forming process, the oxygen content in the forming chamber can be below 0.1%.

[0019] In this invention, after laser selective melting and forming, an alloy sample with a shaped microstructure density exceeding 99.5% can generally be obtained.

[0020] In this invention, the heat treatment can generally be carried out under vacuum conditions or a protective atmosphere.

[0021] In this invention, the heating temperature of the first heat treatment is preferably 1175°C, and the time for maintaining the heating temperature is preferably 1 hour.

[0022] In this invention, the heating temperature of the second heat treatment is preferably 1175°C. The time for maintaining the heating temperature is preferably 2 hours.

[0023] The second heat treatment is preferably hot isostatic pressing.

[0024] In this invention, the heating temperature of the third heat treatment is preferably 1175°C. The time for maintaining the heating temperature is preferably 1 hour.

[0025] In this invention, the heating temperature of the fourth heat treatment is preferably 760°C. The time for maintaining the heating temperature is preferably 0.5 h.

[0026] In this invention, the heat treatment preferably includes:

[0027] First heat treatment: The alloy is heated to 1160-1180℃ in the furnace, held for 1 hour, and then the furnace is cooled to below 400℃.

[0028] Second hot isostatic pressing treatment: The sample after the first heat treatment is heated to 1175℃ in the furnace and held at 160MPa for 2 hours, and then cooled to below 400℃ in the furnace.

[0029] Third heat treatment: The sample after the second hot isostatic pressing treatment is heated to 1175℃ in the furnace, held for 1 hour, and then air-cooled until room temperature (30~40℃).

[0030] Fourth heat treatment: The sample after the third heat treatment is heated to 760℃ in the furnace, held at that temperature for 0.5h, and then air-cooled until room temperature (30~40℃).

[0031] The second technical solution provided by the present invention is: a nickel-based alloy, which is prepared by the above-mentioned method for preparing nickel-based alloys.

[0032] In this invention, the nickel-based alloy can be conventional in the art, such as a nickel-based alloy with the grade Hastelloy X.

[0033] In this invention, the nickel-based alloy contains finely dispersed, continuous, thin-film carbides within the grains and at the grain boundaries.

[0034] The third technical solution provided by the present invention is: the application of the nickel-based alloy in hot-end components of aero-engines and gas turbines.

[0035] Based on common knowledge in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of the present invention.

[0036] The reagents and raw materials used in this invention are all commercially available.

[0037] The positive and progressive effects of this invention are as follows:

[0038] By optimizing the process parameters in the laser selective melting and heat treatment steps, the nickel-based alloy preparation method of this invention can produce Hastelloy X alloy containing finely dispersed intragranular and continuous thin-film carbides at grain boundaries. Furthermore, the defects such as voids and cracks in the formed Hastelloy X alloy are significantly reduced, residual stress and harmful phases are eliminated, and the microstructure is uniform and dense, effectively improving the high-temperature mechanical properties and mid-temperature creep rupture properties of the laser selective melting Hastelloy X alloy.

[0039] By using laser selective melting forming technology, short-cycle manufacturing of complex Hastelloy X alloy structural parts is achieved, and the high-temperature mechanical properties exceed the standard requirements for forgings, further improving the performance and durability of Hastelloy X alloy structural parts.

[0040] The method for preparing nickel-based alloys in this invention can adjust the grain size of Hastelloy X alloys, control the morphology and distribution of intragranular precipitates, and improve intragranular strength; it can also regulate the morphology and content of grain boundary precipitates and improve grain boundary bonding. Attached Figure Description

[0041] Figure 1 SEM images of the heat-treated / hot isostatic pressing microstructure of Hastelloy X alloy prepared by SLM in Example 1.

[0042] Figure 2 SEM images of the heat-treated / hot isostatically pressed microstructure of Hastelloy X alloy prepared by SLM in Comparative Example 1.

[0043] Figure 3 SEM images of the heat-treated microstructure of Hastelloy X alloy prepared by SLM in Comparative Example 2.

[0044] Figure 4 SEM images of the heat-treated microstructure of Hastelloy X alloy prepared by SLM in Comparative Example 3. Detailed Implementation

[0045] The present invention is further illustrated below by way of embodiments, but the invention is not limited to the scope of the embodiments described herein. Experimental methods in the following embodiments that do not specify specific conditions were performed according to conventional methods and conditions, or as selected according to the product instructions.

[0046] Example 1

[0047] 1. The equipment involved in the preparation method of Hastelloy X alloy includes:

[0048] (A) Stainless steel alloy substrate, used as a prefabricated substrate in the forming process;

[0049] (B) A circulating filtration system to prevent oxidation during the forming process in the forming chamber;

[0050] (C) A semiconductor laser is used as a laser source to melt metal powder;

[0051] (D) Powder bed system to ensure continuous forming process;

[0052] (E) Scanning galvanometer system to ensure the formed shape and size;

[0053] (F) Vacuum heat treatment furnace, used to perform vacuum heat treatment on the formed block;

[0054] (G) Hot isostatic pressing furnace, used to perform hot isostatic pressing on the sample.

[0055] 2. The preparation method of Hastelloy X alloy includes the following steps:

[0056] The nickel-based alloy raw material can be subjected to laser selective melting and heat treatment in sequence.

[0057] The laser selective melting forming process involves: in an argon-filled inert atmosphere chamber, using a semiconductor laser as the laser source, continuously melting and depositing Hastelloy X alloy powder pre-placed in a powder bed onto a stainless steel alloy substrate layer by layer. By controlling the process parameters and deposition zone size during the deposition process, Hastelloy X is prepared by laser selective melting forming. The laser power is 250W; the spot diameter is 0.1mm; the scanning speed is 1050mm / s; the scanning spacing is 0.1mm; and the powder layer thickness can be 0.04mm.

[0058] The heat treatment includes four stages:

[0059] First heat treatment: The alloy is heated to 1160-1180℃ in the furnace, held for 1 hour, and then the furnace is cooled to below 400℃.

[0060] Second hot isostatic pressing treatment: The sample after the first heat treatment is heated to 1175℃ in the furnace and held at 160MPa for 2 hours, and then cooled to below 400℃ in the furnace.

[0061] Third heat treatment: The sample after the second hot isostatic pressing treatment is heated to 1175℃ in the furnace, held for 1 hour, and then air-cooled until room temperature (30~40℃).

[0062] Fourth heat treatment: The sample after the third heat treatment is heated to 760℃ in the furnace, held at that temperature for 0.5h, and then air-cooled until room temperature (30~40℃).

[0063] Specifically, the method includes the following steps:

[0064] Step 1: Place Hastelloy X alloy powder with a particle size of 15-45μm into the powder supply hopper;

[0065] Step 2: Place the stainless steel substrate into the argon-filled inert atmosphere processing chamber and fix it on the worktable;

[0066] Step 3: Turn on the circulating filtration system to reduce the oxygen content in the processing chamber until the oxygen content is below 1000ppm, and then start the high-temperature alloy additive manufacturing process.

[0067] Step 4: Using a powder bed system, Hastelloy X alloy powder is pre-placed on the substrate. A semiconductor laser is used as the laser source, and a scanning galvanometer system melts and shapes the powder on the substrate according to a pre-set path. For each layer formed, the substrate descends 40 μm, the powder bed system again pre-places Hastelloy X alloy powder on the substrate, and the laser melts the powder according to the pre-set path. This process is repeated until the pre-set procedure is complete.

[0068] Step 5: After deposition is complete, open the argon-filled inert atmosphere protection chamber and remove the alloy parts;

[0069] Step 6: Perform the above four heat treatments on the alloy parts.

[0070] 3. Perform performance tests on the heat-treated Hastelloy X alloy parts.

[0071] (1) The medium-temperature creep performance was measured by a high-temperature creep tester, and the test results are shown in Table 1 below.

[0072] Table 1

[0073]

[0074] The microstructure of the Hastelloy X alloy after quadruple heat treatment in Example 1 is shown in the figure below. Figure 1 As shown.

[0075] From Table 1 and Figure 1 It is evident that obtaining Hastelloy X samples containing finely dispersed intracrystalline and continuously distributed thin-film carbides at grain boundaries through quadruple heat treatment can significantly improve the mid-temperature creep performance of Hastelloy X formed by laser selective melting.

[0076] (2) Tensile properties were measured using an MTS Landmark 370.10 testing machine. The test results are shown in Table 2 below.

[0077] Table 2

[0078]

[0079] As shown in Table 2, the Hastelloy X alloys prepared by SLM in Example 1 all meet the Hastelloy X forging standard requirements.

[0080] Comparative Example 1

[0081] 1. The equipment involved in the preparation method of Hastelloy X alloy includes:

[0082] (A) Stainless steel alloy substrate, used as a prefabricated substrate in the forming process;

[0083] (B) A circulating filtration system to prevent oxidation during the forming process in the forming chamber;

[0084] (C) A semiconductor laser is used as a laser source to melt metal powder;

[0085] (D) Powder bed system to ensure continuous forming process;

[0086] (E) Scanning galvanometer system to ensure the formed shape and size;

[0087] (F) Vacuum heat treatment furnace, used to perform vacuum heat treatment on the formed block;

[0088] (G) Hot isostatic pressing furnace, used to perform hot isostatic pressing on the sample.

[0089] 2. The preparation method of Hastelloy X alloy includes the following steps:

[0090] The nickel-based alloy raw material can be subjected to laser selective melting and heat treatment in sequence.

[0091] The laser selective melting forming process involves: in an argon-filled inert atmosphere chamber, using a semiconductor laser as the laser source, continuously melting and depositing Hastelloy X alloy powder pre-placed in a powder bed onto a stainless steel alloy substrate layer by layer. By controlling the process parameters and deposition zone size during the deposition process, Hastelloy X is prepared by laser selective melting forming. The laser power is 250W; the spot diameter is 0.1mm; the scanning speed is 1050mm / s; the scanning spacing is 0.1mm; and the powder layer thickness can be 0.04mm.

[0092] The heat treatment includes two stages:

[0093] First heat treatment: vacuum degree less than 10 -8 The alloy was heated to 1175°C in the furnace and held for 1 hour, then the furnace was cooled to below 400°C.

[0094] Second heat treatment: The sample after the first heat treatment is heated to 1175℃ and held at 160MPa for 2 hours in the furnace, and then cooled to below 400℃ in the furnace.

[0095] Specifically, the method includes the following steps:

[0096] Step 1: Place Hastelloy X alloy powder with a particle size of 15-45μm into the powder supply hopper;

[0097] Step 2: Place the stainless steel substrate into the argon-filled inert atmosphere processing chamber and fix it on the worktable;

[0098] Step 3: Turn on the circulating filtration system to reduce the oxygen content in the processing chamber until the oxygen content is below 1000ppm, and then start the high-temperature alloy additive manufacturing process.

[0099] Step 4: Using a powder bed system, Hastelloy X alloy powder is pre-placed on the substrate. A semiconductor laser is used as the laser source, and a scanning galvanometer system melts and shapes the powder on the substrate according to a pre-set path. For each layer formed, the substrate descends 40 μm, the powder bed system again pre-places Hastelloy X alloy powder on the substrate, and the laser melts the powder according to the pre-set path. This process is repeated until the pre-set procedure is complete.

[0100] Step 5: After deposition is complete, open the argon-filled inert atmosphere protection chamber and remove the alloy parts;

[0101] Step 6: Perform the above two heat treatments on the alloy parts.

[0102] 3. Perform performance tests on the heat-treated Hastelloy X alloy parts.

[0103] (1) The medium-temperature creep performance was measured by a high-temperature creep tester, and the test results are shown in Table 3 below.

[0104] Table 3

[0105]

[0106] The microstructure of Hastelloy X alloy in Comparative Example 1 after double heat treatment is shown in the figure below. Figure 2 As shown.

[0107] From Table 3 and Figure 2 It can be seen that the Hastelloy X sample, which has a small amount of blocky carbide structure within the grains and a large amount of continuous thin film carbide structure at the grain boundaries after two heat treatments, has a lower medium-temperature creep performance than Example 1.

[0108] (2) Tensile properties were measured using an MTS Landmark 370.10 testing machine. The test results are shown in Table 4 below.

[0109] Table 4

[0110]

[0111]

[0112] As can be seen from Table 4, although the Hastelloy X alloys prepared by SLM in Comparative Example 1 all meet the standard requirements for Hastelloy X forgings, their tensile properties are significantly inferior to those in Example 1.

[0113] Comparative Example 2

[0114] 1. The equipment involved in the preparation method of Hastelloy X alloy includes:

[0115] (A) Stainless steel alloy substrate, used as a prefabricated substrate in the forming process;

[0116] (B) A circulating filtration system to prevent oxidation during the forming process in the forming chamber;

[0117] (C) A semiconductor laser is used as a laser source to melt metal powder;

[0118] (D) Powder bed system to ensure continuous forming process;

[0119] (E) Scanning galvanometer system to ensure the formed shape and size;

[0120] (F) Vacuum heat treatment furnace, used to perform vacuum heat treatment on the formed block.

[0121] 2. The preparation method of Hastelloy X alloy includes the following steps:

[0122] The nickel-based alloy raw material can be subjected to laser selective melting and heat treatment in sequence.

[0123] The laser selective melting forming process involves: in an argon-filled inert atmosphere chamber, using a semiconductor laser as the laser source, continuously melting and depositing Hastelloy X alloy powder pre-placed in a powder bed onto a stainless steel alloy substrate layer by layer. By controlling the process parameters and deposition zone size during the deposition process, Hastelloy X is prepared by laser selective melting forming. The laser power is 255W; the spot diameter is 0.1mm; the scanning speed is 1100mm / s; the scanning spacing is 0.09mm; and the powder layer thickness can be 0.04mm.

[0124] The heat treatment includes a first heat treatment:

[0125] First heat treatment: vacuum degree less than 10 -8 The alloy was heated to 1160℃ in the furnace and held for 1 hour, then backfilled with 2 bar Ar and air-cooled to below 400℃.

[0126] Specifically, the method includes the following steps:

[0127] Step 1: Place Hastelloy X alloy powder with a particle size of 15-45μm into the powder supply hopper;

[0128] Step 2: Place the stainless steel substrate into the argon-filled inert atmosphere processing chamber and fix it on the worktable;

[0129] Step 3: Turn on the circulating filtration system to reduce the oxygen content in the processing chamber until the oxygen content is below 1000ppm, and then start the high-temperature alloy additive manufacturing process.

[0130] Step 4: Using a powder bed system, Hastelloy X alloy powder is pre-placed on the substrate. A semiconductor laser is used as the laser source, and a scanning galvanometer system melts and shapes the powder on the substrate according to a pre-set path. For each layer formed, the substrate descends 40 μm, the powder bed system again pre-places Hastelloy X alloy powder on the substrate, and the laser melts the powder according to the pre-set path. This process is repeated until the pre-set procedure is complete.

[0131] Step 5: After deposition is complete, open the argon-filled inert atmosphere protection chamber and remove the alloy parts;

[0132] Step 6: Perform the above-mentioned heat treatment on the alloy parts; for the first heat treatment, the vacuum degree is less than 10-8 bar, the alloy is heated to 1160℃ in the furnace and held for 1 hour, and then backfilled with 2 bar Ar and air cooled to below 400℃.

[0133] 3. The high-temperature creep tester was used to test the creep performance of the heat-treated Hastelloy X alloy parts. The results are shown in Table 5 below.

[0134] Table 5

[0135]

[0136]

[0137] The microstructure of Hastelloy X alloy in Comparative Example 2 after a first heat treatment is shown in the figure below. Figure 3 As shown.

[0138] From Table 5 and Figure 3 It can be seen that the Hastelloy X sample obtained after one heat treatment has little or no carbide structure characteristics in the grains and grain boundaries, and its mid-temperature creep performance is not as good as that of Example 1.

[0139] Comparative Example 3

[0140] 1. The equipment involved in the preparation method of Hastelloy X alloy includes:

[0141] (A) Stainless steel alloy substrate, used as a prefabricated substrate in the forming process;

[0142] (B) A circulating filtration system to prevent oxidation during the forming process in the forming chamber;

[0143] (C) A semiconductor laser is used as a laser source to melt metal powder;

[0144] (D) Powder bed system to ensure continuous forming process;

[0145] (E) Scanning galvanometer system to ensure the formed shape and size;

[0146] (F) Vacuum heat treatment furnace, used to perform vacuum heat treatment on the formed block;

[0147] (G) Hot isostatic pressing furnace, used to perform hot isostatic pressing on the sample.

[0148] 2. The preparation method of Hastelloy X alloy includes the following steps:

[0149] The nickel-based alloy raw material can be subjected to laser selective melting and heat treatment in sequence.

[0150] The laser selective melting forming process involves: in an argon-filled inert atmosphere chamber, using a semiconductor laser as the laser source, continuously melting and depositing Hastelloy X alloy powder pre-placed in a powder bed onto a stainless steel alloy substrate layer by layer. By controlling the process parameters and deposition zone size during the deposition process, Hastelloy X is prepared by laser selective melting forming. The laser power is 260W; the spot diameter is 0.1mm; the scanning speed is 1000mm / s; the scanning spacing is 0.1mm; and the powder layer thickness can be 0.04mm.

[0151] The heat treatment includes four heat treatments;

[0152] First heat treatment: The alloy is heated to 1175℃ in the furnace and held for 1 hour, then the furnace is cooled to below 400℃;

[0153] Second hot isostatic pressing treatment: The sample after the first heat treatment is heated to 1175℃ in the furnace and held at 160MPa for 2 hours, and then cooled to below 400℃ in the furnace.

[0154] Third heat treatment: After the second hot isostatic pressing treatment, the sample is heated to 1175 °C in the furnace and held for 1 hour, then air-cooled until room temperature.

[0155] Fourth heat treatment: The sample after the third heat treatment was heated to 980℃ in the furnace, held at that temperature for 1 hour, and then air-cooled until room temperature.

[0156] Specifically, the method includes the following steps:

[0157] Step 1: Place Hastelloy X alloy powder with a particle size of 15-45μm into the powder supply hopper;

[0158] Step 2: Place the stainless steel substrate into the argon-filled inert atmosphere processing chamber and fix it on the worktable;

[0159] Step 3: Turn on the circulating filtration system to reduce the oxygen content in the processing chamber until the oxygen content is below 1000ppm, and then start the high-temperature alloy additive manufacturing process.

[0160] Step 4: Using a powder bed system, Hastelloy X alloy powder is pre-placed on the substrate. A semiconductor laser is used as the laser source, and a scanning galvanometer system melts and shapes the powder on the substrate according to a pre-set path. For each layer formed, the substrate descends 40 μm, the powder bed system again pre-places Hastelloy X alloy powder on the substrate, and the laser melts the powder according to the pre-set path. This process is repeated until the pre-set procedure is complete.

[0161] Step 5: After deposition is complete, open the argon-filled inert atmosphere protection chamber and remove the alloy parts.

[0162] Step 6: Perform the above four heat treatments on the alloy parts.

[0163] 3. The creep performance of the heat-treated Hastelloy X alloy parts was tested using a high-temperature creep testing machine. The results are shown in Table 6 below.

[0164] Table 6

[0165]

[0166] The microstructure of Hastelloy X alloy in Comparative Example 3 after quadruple heat treatment is shown in the figure below. Figure 4 As shown.

[0167] From Table 6 and Figure 4 It can be seen that by subjecting the deposited parts to four heat treatments, a Hastelloy X sample with a microstructure characterized by dispersed intragranular and discontinuous grain boundary carbides was obtained, and its mid-temperature creep performance was not as good as that of Example 1.

[0168] As can be seen from the examples and comparative examples, there is a synergistic effect between the various processes and condition parameters of the present invention. When a certain parameter or process step of heat treatment is not within the protection scope of the present invention, the performance of the resulting product is far inferior to that of the present invention.

Claims

1. A method of producing a nickel-based alloy, characterized by, The nickel-based alloy is Hastelloy X, which comprises the following steps: sequentially performing laser selective melting forming treatment and heat treatment on a nickel-based alloy raw material, the nickel-based alloy raw material is an alloy powder, the alloy powder comprises Cr, Co, Nb, Ti, Al, Ta, Ni and B; the average particle size of the alloy powder is 15-45 μm; In the laser selective melting forming, the laser power is 250-255 W; And / or, in the laser selective melting forming, the spot diameter is 0.1 mm; And / or, in the laser selective melting forming, the scanning speed is 1000-1100 mm / s; And / or, in the laser selective melting forming, the scanning interval is 0.09-0.1 mm; And / or, in the laser selective melting forming, the powder layer thickness is 0.04 mm; The heat treatment comprises first heat treatment, second heat treatment, third heat treatment and fourth heat treatment; The heating temperature of the first heat treatment is 1160-1180 °C, and the time for maintaining the heating temperature is 0.9-1.1 h; after maintaining the heating temperature for 0.9-1.1 h, cooling is performed; the cooling temperature is below 400 °C; The heating temperature of the second heat treatment is 1165-1185 °C, and the time for maintaining the heating temperature is 1.9-2.1 h; the pressure for maintaining the heating temperature is 160 MPa; after maintaining the heating temperature for 1.9-2.1 h, cooling is performed; the cooling temperature is below 400 °C; The heating temperature of the third heat treatment is 1165-1185 °C, and the time for maintaining the heating temperature is 0.9-1.1 h; after maintaining the heating temperature for 0.9-1.1 h, cooling is performed; the cooling temperature is 30-40 °C; The heating temperature of the fourth heat treatment is 750-770 °C, and the time for maintaining the heating temperature is 0.4-0.6 h; after maintaining the heating temperature for 0.4-0.6 h, cooling is performed; the cooling temperature is 30-40 °C; In the obtained finished nickel-based alloy, there are fine and dispersed intracrystalline carbides and continuous thin film carbides at the grain boundaries.

2. The method of producing a nickel-based alloy according to claim 1, wherein The laser selective melting forming is performed in an argon atmosphere; in the argon atmosphere, the purity of argon is above 99.99 wt%; And / or, in the laser selective melting forming, the oxygen content in the forming bin is below 0.1%.

3. The method of producing a nickel-based alloy according to claim 1, wherein The heat treatment is performed in a vacuum condition or a protective atmosphere.

4. The method of producing a nickel-based alloy according to claim 1, wherein The heating temperature of the first heat treatment is 1175 °C; the time for maintaining the heating temperature is 1 h; And / or, the heating temperature of the second heat treatment is 1175 °C; the time for maintaining the heating temperature is 2 h; And / or, the second heat treatment is a hot isostatic pressing treatment; And / or, the heating temperature of the third heat treatment is 1175 °C; the time for maintaining the heating temperature is 1 h; And / or, the heating temperature of the fourth heat treatment is 760 °C; the time for maintaining the heating temperature is 0.5 h.

5. The method of producing a nickel-based alloy according to claim 1, wherein The heat treatment comprises: First heat treatment: the alloy is heated to 1160-1180℃, and after holding for 1h, the furnace is cooled to below 400℃; Second heat treatment: the sample after the first heat treatment is heated to 1175℃, and after holding for 2h under the condition of 160MPa, the furnace is cooled to below 400℃; Third heat treatment: the sample after the second heat treatment is heated to 1175℃, and after holding for 1h, the sample is air-cooled until 30-40℃; Fourth heat treatment: the sample after the third heat treatment is heated to 760℃, and after holding for 0.5h, the sample is air-cooled until 30-40℃.

6. A nickel-based alloy characterized in that, The nickel-based alloy is prepared by the method of any one of claims 1-5.

7. Use of the nickel-based alloy according to claim 6 in hot end components of aeroengines and gas turbines.

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