Spherical high-temperature alloy powder for additive manufacturing and preparation method thereof

Abstract

The present invention relates to the technical field of additive manufacturing, and in particular to a spherical high-temperature alloy powder for additive manufacturing and a preparation method thereof. The spherical high-temperature alloy powder for additive manufacturing of the present invention comprises the following raw material components by weight percentage: Cr 12-14%, Co 8-9%, Al 3.8-4.2%, Ti 3.8-4.2%, W 2.4-2.8%, Ta 1.9-2.1%, Mo 1.6-2.0%, Nb 1.0-1.2%, Fe 0.1-5.0%, doped Si3N 4 0.2‑1%, C 0.08‑0.12%, Mn≤0.02%, Zr<0.03%, and the balance is Ni and impurity elements. By introducing Sr and Tb elements into the matrix, it has excellent durability, hot working performance and thermoplasticity under high temperature conditions, which can make the subsequent processing of the high-temperature alloy simpler, expand the application field, and has broad application prospects and significant impact significance.

Description

Technical Field

[0001] The present invention relates to the technical field of additive manufacturing, and in particular to a spherical high-temperature alloy powder for additive manufacturing and a preparation method thereof. Background Art

[0002] Additive Manufacturing, also known as 3D printing technology, is a new type of digital controlled material processing and manufacturing technology that has developed rapidly in recent years. The three-dimensional computer model of the part is divided into discrete two-dimensional slice data through professional layering software, and then the two-dimensional structure is stacked layer by layer through digitally controlled 3D printing processing equipment to finally complete the production of the part. Compared with traditional manufacturing technology, AM technology has the advantages of no mold, flexibility, and high material utilization. Most importantly, this advanced manufacturing technology provides an efficient and feasible solution for the production of parts with complex internal and external structures.

[0003] Nickel-based superalloys have excellent tensile strength, creep resistance, fatigue resistance and oxidation resistance in the temperature range of 540-1000℃, and are the must-have materials for key high-temperature components in core components such as aircraft engines and gas turbines. Obtaining high-quality nickel-based alloy powder is the basis and guarantee for obtaining high-performance nickel-based superalloys.

[0004] Patent technical document CN202111671842.6 discloses a method for manufacturing nickel-based high-temperature alloy performance through carbide-enhanced additive manufacturing, nickel-based high-temperature alloy powder and its application. The invention uses nickel-based high-temperature alloy powder as raw material, mechanically mixes TiC powder, and forms it through additive manufacturing technology; wherein the TiC powder exists in a mass fraction of 9.5-10%. The carbide-enhanced nickel-based high-temperature alloy formed parts prepared by this invention have the characteristics of high density, high microhardness, low friction coefficient and low wear rate. Compared with the unreinforced nickel-based alloy formed by selective laser melting, its mechanical properties are significantly improved. However, it ignores the problem of poor compatibility between the ceramic reinforcement phase and the matrix, which will affect the mechanical properties of the printed parts.

[0005] Patent technology document CN202110078587.8 discloses a high-γ′ content nickel-based high-temperature alloy powder for additive manufacturing, a method of using the same, and a nickel-based high-temperature alloy component. Using this high-temperature alloy powder, a dense, crack-free, complex component that meets the strength requirements in an ultra-high temperature environment can be printed through selective laser melting technology. However, it does not take into account that the hardness of the alloy is too high under high temperature conditions, which will greatly affect its processing performance. Summary of the invention

[0006] In view of this, the purpose of the present invention is to propose a spherical high-temperature alloy powder for additive manufacturing and a preparation method thereof, so as to provide a spherical high-temperature alloy powder for additive manufacturing that does not affect its mechanical properties under high temperature conditions and also has good plasticity.

[0007] Based on the above purpose, the present invention provides a spherical high-temperature alloy powder for additive manufacturing, which includes the following raw material components by weight percentage: Cr12-14%, Co8-9%, Al3.8-4.2%, Ti3.8-4.2%, W2.4-2.8%, Ta1.9-2.1%, Mo1.6-2.0%, Nb1.0-1.2%, Fe0.1-5.0%, doped Si3N40.2-1%, C0.08-0.12%, Mn≤0.02%, Zr<0.03%, and the balance is Ni and impurity elements;

[0008] Preferably, the purity of the above raw materials is not less than 3N.

[0009] The preparation steps of the doped Si3N4 are as follows:

[0010] Sr3N2, Si3N4 and Tb4O7 are mixed and then ground under a nitrogen atmosphere to obtain a mixed powder; the mixed powder is then calcined at 1300-1600°C under a reducing atmosphere to obtain doped Si3N4.

[0011] Preferably, the particle size of the Si3N4 is 20-40 nm.

[0012] Preferably, the particle size of the Sr3N2 is 50-100 nm.

[0013] Preferably, the particle size of Tb4O7 is 30-80nm.

[0014] Preferably, the reducing atmosphere is a mixture of 10 vol.% H2 and 90 vol.% N2.

[0015] Preferably, the calcination time is 7-9h.

[0016] Preferably, the weight ratio of Sr3N2, Si3N4 and Tb4O7 is 1-5:10-15:0.1-0.3.

[0017] Furthermore, the present invention also provides a method for preparing spherical high-temperature alloy powder for additive manufacturing, and the specific preparation steps are as follows:

[0018] (1) Under an argon atmosphere, adding the raw material components into a melting furnace according to proportions, melting, and obtaining a composite alloy melt;

[0019] (2) The composite alloy melt is broken into fine droplets by gas atomization, and the composite alloy powder is obtained after solidification;

[0020] (3) The composite alloy powder is screened and dried to obtain spherical high-temperature alloy powder for additive manufacturing.

[0021] Preferably, the smelting temperature in step (1) is 1400-1600°C.

[0022] Preferably, the gas flow of the atomization method in step (2) is high-purity argon gas, with a pressure of 8 MPa-10 MPa and a velocity of 300-700 m / s.

[0023] Preferably, the particle size of the spherical high-temperature alloy powder for additive manufacturing in step (3) is 15-53 μm.

[0024] Preferably, the drying temperature in step (3) is 55-115° C., the vacuum degree is ≤1000 Pa, and the drying time is 6-8 h.

[0025] Beneficial effects of the present invention:

[0026] The spherical high-temperature alloy powder for additive manufacturing of the present invention introduces Sr and Tb elements into a nickel alloy matrix, thereby improving the durability and thermoplasticity of the nickel alloy under high temperature conditions.

[0027] The spherical high-temperature alloy powder for additive manufacturing of the present invention is prepared by introducing Sr and Tb elements into a nickel alloy matrix. The two elements have a synergistic effect on each other and jointly promote the durability and thermoplasticity of the nickel alloy under high temperature conditions.

[0028] The spherical high-temperature alloy powder for additive manufacturing of the present invention introduces Sr and Tb elements by doping rather than simply mixing, so that the durability and hot working performance of the nickel alloy under high temperature conditions are improved. DETAILED DESCRIPTION

[0029] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.

[0030] The sources or properties of the raw materials used in the present invention are as follows: Si3N4 was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. with the item number S431557 and a particle size of 30 nm; Sr3N2 was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. with the item number S302598 and a particle size of 80 nm; Tb4O7 was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. with the item number T124754 and a particle size of 50 nm.

[0031] Example 1: A spherical high-temperature alloy powder for additive manufacturing, the specific preparation steps are as follows:

[0032] (1) In a nitrogen atmosphere, 1 kg Sr3N2, 10 kg Si3N4 and 0.1 kg Tb4O7 were mixed and ground to obtain a mixed powder, and then the mixed powder was calcined at 1300 ° C for 7 h in a reducing atmosphere (10 vol.% H2 and 90 vol.% N2) to obtain doped Si3N4;

[0033] (2) Add 10 kg of Cr12%, Co8%, Al3.8%, Ti3.8%, W2.4%, Ta1.9%, Mo1.6%, Nb1.0%, Fe0.1%, doped Si3N40.2%, C0.08%, Mn0.01%, Zr0.01% and the rest of nickel into a melting furnace and melt at 1400°C to obtain a composite alloy melt;

[0034] (3) In an argon atmosphere, the composite alloy melt is blown out by a gas atomization method, the gas flow is high-purity argon gas, the pressure is 8 MPa, and the speed is 300 m / s, and the composite alloy powder is obtained after cooling;

[0035] (4) The composite alloy powder was sieved and dried at 55°C and a vacuum degree of 900 Pa for 6 h to obtain a spherical high-temperature alloy powder for additive manufacturing with a particle size of 15-53 μm.

[0036] Example 2: A spherical high-temperature alloy powder for additive manufacturing, the specific preparation steps are as follows:

[0037] (1) In a nitrogen atmosphere, 3 kg Sr3N2, 13 kg Si3N4 and 0.2 kg Tb4O7 were mixed and ground to obtain a mixed powder, which was then calcined at 1500 °C for 8 h in a reducing atmosphere (10 vol. % H2 and 90 vol. % N2) to obtain doped Si3N4;

[0038] (2) Add 10 kg of raw materials, including 13% Cr, 8.5% Co, 4% Al, 4% Ti, 2.6% W, 2% Ta, 1.8% Mo, 1.1% Nb, 3.0% Fe, 0.6% doped Si3N4, 0.1% C, 0.01% Mn, 0.01% Zr, and the remainder nickel, into a melting furnace and melt at 1500° C. to obtain a composite alloy melt;

[0039] (3) In an argon atmosphere, the composite alloy melt is blown out by a gas atomization method, the gas flow is high-purity argon gas, the pressure is 9 MPa, and the speed is 500 m / s, and the composite alloy powder is obtained after cooling;

[0040] (4) The composite alloy powder was sieved and dried at 80°C and a vacuum degree of 900 Pa for 7 h to obtain a spherical high-temperature alloy powder for additive manufacturing with a particle size of 15-53 μm.

[0041] Example 3: A spherical high-temperature alloy powder for additive manufacturing, the specific preparation steps are as follows:

[0042] (1) In a nitrogen atmosphere, 4 kg Sr3N2, 12 kg Si3N4 and 0.3 kg Tb4O7 were mixed and ground to obtain a mixed powder, which was then calcined at 1400 °C for 9 h in a reducing atmosphere (10 vol. % H2 and 90 vol. % N2) to obtain doped Si3N4;

[0043] (2) Add 14% Cr, 9% Co, 4.2% Al, 4.2% Ti, 2.8% W, 1.9% Ta, 2.0% Mo, 1.2% Nb, 5.0% Fe, 1% doped Si3N4, 0.12% C, 0.01% Mn, 0.01% Zr, and the remainder nickel, totaling 10 kg, into a melting furnace, and melt at 1500° C. to obtain a composite alloy melt;

[0044] (3) In an argon atmosphere, the composite alloy melt is blown out by a gas atomization method, the gas flow is high-purity argon gas, the pressure is 10 MPa, and the speed is 700 m / s, and the composite alloy powder is obtained after cooling;

[0045] (4) The composite alloy powder was sieved and dried at 100°C and a vacuum degree of 900 Pa for 8 h to obtain a spherical high-temperature alloy powder for additive manufacturing with a particle size of 15-53 μm.

[0046] Example 4: A spherical high-temperature alloy powder for additive manufacturing, the specific preparation steps are as follows:

[0047] (1) In a nitrogen atmosphere, 5 kg Sr3N2, 15 kg Si3N4 and 0.3 kg Tb4O7 were mixed and ground to obtain a mixed powder, which was then calcined at 1600 °C for 9 h in a reducing atmosphere (10 vol. % H2 and 90 vol. % N2) to obtain doped Si3N4;

[0048] (2) Add 10 kg of Cr 14%, Co 9%, Al 4.2%, Ti 4.2%, W 2.8%, Ta 2.1%, Mo 12.0%, Nb 1.2%, Fe 5.0%, doped Si3N41%, C 0.12%, Mn 0.01%, Zr 0.01%, and the remainder nickel into a melting furnace and melt the raw materials at 11600° C. to obtain a composite alloy melt;

[0049] (3) In an argon atmosphere, the composite alloy melt is blown out by a gas atomization method, the gas flow is high-purity argon gas, the pressure is 10 MPa, and the speed is 700 m / s, and the composite alloy powder is obtained after cooling;

[0050] (4) The composite alloy powder was sieved and dried at 115°C and a vacuum degree of 900 Pa for 8 h to obtain a spherical high-temperature alloy powder for additive manufacturing with a particle size of 15-53 μm.

[0051] Comparative Example 1: A high temperature alloy powder, the specific preparation steps are as follows:

[0052] The difference from Example 2 is that Sr3N2 is not added to the raw materials.

[0053] Comparative Example 2: A high temperature alloy powder, the specific preparation steps are as follows:

[0054] The difference from Example 2 is that no Tb4O7 is added to the raw materials.

[0055] Comparative Example 3: A high temperature alloy powder, the specific preparation steps are as follows:

[0056] (1) Add 13% Cr, 8.5% Co, 4% Al, 4% Ti, 2.6% W, 2% Ta, 1.8% Mo, 1.1% Nb, 3.0% Fe, 0.11% Sr3N2, 0.48% Si3N4, 0.01% Tb4O7, 0.1% C, 0.01% Mn, 0.01% Zr, and the remainder nickel, totaling 10 kg, into a melting furnace, and melt at 1500° C. to obtain a composite alloy melt;

[0057] (2) In an argon atmosphere, the composite alloy melt is blown out by a gas atomization method, the gas flow is high-purity argon gas, the pressure is 9 MPa, and the speed is 500 m / s, and the composite alloy powder is obtained after cooling;

[0058] (3) The composite alloy powder was sieved and dried at 80°C and a vacuum degree of 900 Pa for 7 h to obtain a spherical high-temperature alloy powder for additive manufacturing with a particle size of 15-53 μm.

[0059] Performance Testing

[0060] Powder flowability:

[0061] The powders obtained in the examples and comparative examples were tested according to GB / T 1482-2010 Standard Funnel Method for Determination of Flowability of Metal Powders (Hall Rheometer). The test results are shown in Table 1.

[0062] The powders obtained in the embodiment and the comparative example were placed in an SLM forming device, 304 stainless steel was selected as a substrate, the substrate was preheated to 120°C, high-purity argon gas with a purity of 99.99wt.% was introduced to make the oxygen content ≤450ppm, and SLM forming was performed. The selective laser melting forming parameters were: laser power of 200W, scanning speed of 800mm / s, processing layer thickness of 40μm, scanning spacing of 53μm, spot diameter of 63μm, and laser linear energy density of 300J / m. The mixed powder was subjected to selective laser melting forming, and the carbide-reinforced nickel-based high-temperature alloy was separated from the substrate by electric spark wire cutting, and heat treatment was performed to obtain a print, and the print was tested for performance:

[0063] Thermal processing performance: The printed parts obtained in the embodiment and the comparative example were subjected to a thermal compression test. They were first heated to 1070°C at a heating rate of 10°C / s, kept at this temperature for 3 minutes, and then heated at a heating rate of 0.001s. -1 Strain rate The printed parts obtained in the embodiment and the comparative example were compressed, and the compression amount was 50% (the true strain was 0.7). To ensure the accuracy of the hot compression test results, each parameter was tested with at least two groups of samples, and the average value was taken. The test results are shown in Table 2.

[0064] Mechanical properties: According to the room temperature tensile standard (GB / T 228.1-2010) and the high temperature tensile standard (GB / T 2039-2012), a double-column electronic universal testing machine was used to perform tensile tests on the printed parts obtained in the embodiment and the comparative example at room temperature (25°C) and high temperature (650°C). The displacement rate of the tensile chuck was 0.3 mm / min before the yield point and 3 mm / min after the yield point. Three samples were tested under each condition, and the results were averaged. The test results are shown in Table 2.

[0065] Durability: According to the high temperature durability standard (GB / T 2039-2012), the durability of the printed parts obtained in the embodiment and the comparative example was tested at 650°C / 890MPa using a double-column electronic universal testing machine. The test results are shown in Table 2.

[0066]

[0067] Data analysis: It can be seen from Table 1 that the spherical high-temperature alloy powder for additive manufacturing of the present invention has good fluidity, indicating that its sphericity is relatively excellent and can meet the requirements of additive printing for powder sphericity.

[0068] It can be seen from Examples 1-4 in Table 2 that the printed parts prepared by using the spherical high-temperature alloy powder for additive manufacturing of the present invention have excellent yield strength both at room temperature and at high temperature, and their endurance performance under high temperature conditions is also relatively excellent, which can reach 1207h at 650°C / 890MPa; most importantly, under high temperature conditions, they have excellent hot processing performance and thermoplasticity, with a cross-sectional shrinkage rate of up to 33.4% and an elongation at break of up to 34.3%.

[0069] It can be seen from Example 2 and Comparative Examples 1-2 that by adding doped Si3N4 to the raw materials, the printed parts can have good yield properties under high temperature conditions while also having excellent hot processing functions and thermoplasticity. This may be because doped Si3N4, while introducing Sr and Tb elements, introduces a new lattice structure and forms a new spatial configuration. This new spatial structure can make the nickel alloy softer and more plastic at high temperatures; and, it can be seen from Example 2 and Comparative Example 3 that the introduction of Sr and Tb into the nickel alloy matrix by doping reduces the content of introduced oxygen and further improves the performance of the nickel alloy matrix.

[0070] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention is limited to these examples. Under the concept of the present invention, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.

Claims

1. A spherical high-temperature alloy powder for additive manufacturing, characterized in that: The raw material components include, by weight percentage: Cr12-14%, Co 8-9%, Al 3.8-4.2%, Ti 3.8-4.2%, W 2.4-2.8%, Ta 1.9-2.1%, Mo 1.6-2.0%, Nb 1.0-1.2%, Fe 0.1-5.0%, doped Si3N40.2-1%, C 0.08-0.12%, Mn≤0.02%, Zr<0.03%, and the balance is Ni and impurity elements; The preparation steps of the doped Si3N4 are as follows: Sr3N2, Si3N4 and Tb4O7 are mixed and then ground under a nitrogen atmosphere to obtain a mixed powder; the mixed powder is then calcined at 1300-1600°C under a reducing atmosphere to obtain doped Si3N4.

2. The spherical high-temperature alloy powder for additive manufacturing according to claim 1, characterized in that: The particle size of the Si3N4 is 50-70nm.

3. The spherical high-temperature alloy powder for additive manufacturing according to claim 1, characterized in that: The particle size of the Sr3N2 is 50-100nm.

4. The spherical high-temperature alloy powder for additive manufacturing according to claim 1, characterized in that: The particle size of the Tb4O7 is 200-500nm.

5. The spherical high-temperature alloy powder for additive manufacturing according to claim 1, characterized in that: The weight ratio of the Sr3N2, Si3N4 and Tb4O7 powders is 1-5:10-15:0.1-0.

3.

6. A method for preparing spherical high-temperature alloy powder for additive manufacturing according to any one of claims 1 to 5, characterized in that: The specific preparation steps are as follows: (1) Under an argon atmosphere, adding the raw material components into a melting furnace according to proportions, melting, and obtaining a composite alloy melt; (2) The composite alloy melt is broken into fine droplets by gas atomization, and the composite alloy powder is obtained after solidification; (3) The composite alloy powder is screened and dried to obtain spherical high-temperature alloy powder for additive manufacturing.

7. The method for preparing spherical high-temperature alloy powder for additive manufacturing according to claim 6, characterized in that: The smelting temperature in step (1) is 1400-1600°C.

8. The method for preparing spherical high-temperature alloy powder for additive manufacturing according to claim 6, characterized in that: The gas flow of the atomization method in step (2) is high-purity argon gas, with a pressure of 8MPa-10MPa and a velocity of 300-700m / s.

9. The method for preparing spherical high-temperature alloy powder for additive manufacturing according to claim 6, characterized in that: The particle size of the spherical high-temperature alloy powder for additive manufacturing described in step (3) is 15-53 μm.

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