High-temperature alloy powder applied to 3D printing, preparation method and molded product of high-temperature alloy powder

Abstract

The invention belongs to the technical field of metal powder processing and alloy, and particularly relates to high-temperature alloy powder applied to 3D printing, a preparation method and a molded product of the high-temperature alloy powder. The high-temperature alloy powder provided by the invention comprises the following components in percentage by weight: 0.05 to 0.09 percent of C element, 0.20 to 0.35 percent of Si element, 0.05 to 0.10 percent of La element, 20 to 24 percent of Cr element, 20 to 24 percent of Ni element, 13 to 16 percent of W element, less than or equal to 3 percent of Fe element, less than or equal to 1.25 percent of Mn element and the balance of Co element, the sphericity degree of the high-temperature alloy powder is not less than 0.92, the flowability of the powder is not higher than 20s / 50g, and non-metallic inclusions are less than 3 per 100g. The preparation method of the high-temperature alloy powder, process parameters of 3D printing and the like are further optimized, the problem that printing forming of aviation and aerospace hot end complex components is prone to cracking is effectively solved, and a 3D printing forming product with good compactness and excellent high-temperature service performance is obtained.

Description

Technical Field

[0001] The present invention belongs to the field of metal powder processing and alloy technology, and specifically relates to a high-temperature alloy powder used in 3D printing, a preparation method and a molded product thereof. Background Art

[0002] High-temperature alloys are a type of material that has excellent mechanical properties, oxidation resistance and creep resistance in high-temperature environments. They are widely used in aerospace, gas turbines, nuclear energy and other fields. Among them, GH5188 is a solid solution-strengthened cobalt-based high-temperature alloy. Due to its good high-temperature thermal strength, high-temperature oxidation resistance and high-temperature creep resistance and other comprehensive properties, this alloy has been widely and maturely used in the manufacture of hot-end components such as aircraft engine combustion chamber flame tubes, tail nozzles, guide vanes, etc. The traditional methods for manufacturing high-temperature alloy components mainly include forming processes such as precision casting, hot forging and machining. However, with the increasing complexity of the structure of the application-end components, these methods have been difficult to meet the structural and performance requirements of material components in high-end fields such as aerospace.

[0003] 3D printing technology has become one of the most widely used additive manufacturing technologies due to its advantages such as being able to form parts with complex shapes or structures in one go, shortening processing cycles, and improving material utilization. However, the GH5188 alloy powder currently used within the traditional composition range is very likely to cause printing cracking during the 3D printing laser forming process. This is due to the local rapid solidification characteristics of the additive manufacturing process, which can easily lead to excessive stress in the molded parts, inducing cracks to initiate and expand at phase boundaries and grain boundaries, leading to material cracking and failure. Therefore, in order to overcome the above challenges, it is of great significance to develop a cobalt-based high-temperature alloy powder specifically for 3D printing and its molded products.

[0004] Chinese patent CN112024869A discloses a SMTGH5188 spherical powder for 3D printing, its preparation method and application. By optimizing the composition of the alloy powder, the hollow powder ratio of the spherical powder is increased. Although the powder has no microcracks in the structure of the formed part after laser powder 3D printing and the density is not less than 99.30%, it has very strict requirements on the laser particle size ratio of the raw materials. Chinese patent CN118773483A discloses a cobalt-based high-temperature alloy powder for 3D printing, its preparation method and application. Through the design of alloy powder composition and the optimization of smelting process, the uniform distribution of γ′ strengthening phase in the cobalt-based high-temperature alloy can be achieved, reducing the risk of stress cracking. However, the composition design of the high-temperature alloy powder in this method cannot completely guarantee that there are no cracks in the product. In summary, although the above patents have their own advantages and disadvantages, the mechanical properties of the molded products processed by alloy powder at high temperatures still need to be improved. Summary of the invention

[0005] In order to solve the above technical problems existing in the prior art, the present invention provides a high-temperature alloy powder, a preparation method and a molded product thereof for 3D printing. By optimizing the composition and content ratio of the high-temperature alloy powder and adaptively optimizing its preparation method, the problems of cracks, pores and poor mechanical properties of the molded products occurring during 3D printing can be solved.

[0006] First, the present invention provides a high-temperature alloy powder for 3D printing, the components of which include: 0.05-0.09wt% of C element, 0.20-0.35wt% of Si element, 0.05-0.10wt% of La element, 20-24wt% of Cr element, 20-24wt% of Ni element, 13-16wt% of W element, ≤3wt% of Fe element, ≤1.25wt% of Mn element and the balance of Co element.

[0007] Further, the high temperature alloy powder may include any content range of C element in 0.05-0.09wt%, 0.06-0.09wt%, 0.07-0.09wt%, 0.08-0.09wt%, 0.05-0.08wt%, 0.05-0.07 wt%, 0.05-0.06 wt%, 0.06-0.07wt%, 0.06-0.08 wt%, 0.07-0.08 wt%, 0.08-0.09 wt%. The present invention limits the carbon element range to 0.05-0.09 wt%, limits the upper limit of the carbon element content, and further limits the total amount of carbides, reduces the brittleness of the alloy, and reduces the tendency of the material to crack.

[0008] Further, the high temperature alloy powder can be selected from 0.20-0.35wt%, 0.20-0.33wt%, 0.20-0.32wt%, 0.20-0.31wt%, 0.20-0.30wt%, 0.20-0.29wt%, 0.20-0.28wt%, 0.20-0.26wt%, 0.20-0.25wt%, 0.20-0.23wt%, 0.20-0.22wt%, 0.22-0.25wt%, 0.22-0.27wt%, 0.22-0.29wt%, 0.22-0.30wt%, 0.22-0.33wt%, 0.22-0.35wt%, 0.25-0.28wt%, 0.25-0.30wt%, 0.25-0.35 wt%, 0.28-0.30 wt%, 0.28-0.33 wt%, 0.28-0.35 wt%, 0.30-0.35wt%, 0.30-0.33 wt%. The upper limit of silicon content is reduced, the possibility of Laves phase formation during printing is reduced, and the crack resistance of the alloy is increased.

[0009] Furthermore, the high temperature alloy powder may contain any content of La in the range of 0.05-0.10wt%, 0.05-0.09wt%, 0.05-0.08wt%, 0.05-0.07wt%, 0.05-0.06wt%, 0.06-0.09wt%, 0.06-0.08wt%, 0.06-0.07wt%, 0.07-0.08wt%, 0.07-0.09wt%, and 0.08-0.09wt%. Strictly adding a specified amount of the rare earth element lanthanum can improve the purity of the alloy liquid during the alloy smelting process, make the carbides in the additive manufacturing molded parts dispersed and precipitated finely, refine the alloy structure, and ensure the high temperature tensile strength, yield and durability of the alloy.

[0010] Furthermore, the high-temperature alloy powder includes 0.05-0.09wt% of C element, 0.20-0.35wt% of Si element, 0.05-0.10wt% of La element, 21-22wt% of Cr element, 22-23wt% of Ni element, 13-15wt% of W element, ≤1wt% of Fe element, ≤0.015wt% of B element, ≤0.5wt% of Mn element and the balance of Co element.

[0011] Furthermore, the method for preparing high-temperature alloy powder for 3D printing includes the following steps: melting the alloy raw materials to 1400-1600°C and fully mixing, transferring to the atomization chamber and atomizing by argon gas at a nozzle pressure of 3.0-4.0MPa, and finally screening and grading the obtained metal powder. When the smelting temperature is too low, the refractory elements in the alloy cannot be fully dissolved, which can easily lead to segregation of the powder components, forming local defects such as segregation and brittle phases during the 3D printing process in subsequent applications, and the melt viscosity is high. It is difficult to break into fine droplets during atomization, resulting in coarse powder particle size, poor sphericity, and high hollow powder content. When the smelting temperature is too high, the fusible body is severely burned, which can easily lead to deviations in the alloy elements from the composition.

[0012] Furthermore, in the preparation method, the alloy raw material components are melted to 1400-1500° C. and the components are mixed evenly, and then the temperature is increased to 1500-1600° C. for transfer to compensate for the temperature loss of the alloy liquid during the transfer process, and then atomization is performed.

[0013] Furthermore, the vacuum degree of the atomization chamber is ≥30Pa, and the nozzle pressure is 3.3-3.6MPa. The nozzle pressure directly affects the kinetic energy of the atomization medium. The higher the pressure, the more complete the melt flow is broken. Too high pressure will increase the probability of droplet collision, increase the satellite particle rate, and may increase air flow turbulence, leading to local oxidation; too low pressure will coarsen the powder particle size, affect the powder recovery rate of the printing section, and increase the alloy cost.

[0014] Furthermore, the particle size of the high-temperature alloy powder is normally distributed, wherein a particle size range of 15-150 μm is suitable for additive manufacturing needs; preferably 15-53 μm or 53-150 μm; high-temperature alloy powder with a particle size of 15-53 μm is used for laser selective melting, and high-temperature alloy powder with a particle size of 53-150 μm is used for directed energy deposition.

[0015] Furthermore, the sphericity of the high-temperature alloy powder is not less than 0.92, the powder fluidity is not higher than 20s / 50g, and the non-metallic inclusions are less than 3 particles / 100g.

[0016] Secondly, the present invention provides a laser selective melting 3D printed molded product, the raw material for preparing the molded product includes the above-mentioned high-temperature alloy powder. The molded product has no printing cracks, a density of ≥99.6%, and a number of pores ≤3 / mm 2 , tensile strength ≥ 200MPa, yield strength ≥ 150MPa, elongation ≥ 50% at 980℃; the alloy matrix structure of the molded product is austenite phase, and the grain boundary phase includes M 23 C6 phase, M 23 The C6 phase is dispersed at the grain boundaries, where M includes Cr, W, etc. A small amount of fine M 23The C6 phase is dispersed at the grain boundaries, which can hinder dislocation movement, strengthen grain boundaries, and improve the strength, hardness and creep resistance of the alloy.

[0017] Furthermore, the molded product is prepared using the high-temperature alloy powder with a particle size range of 15 to 53 μm provided by the present invention.

[0018] Furthermore, the method for preparing the molded product includes the step of molding high-temperature alloy powder in a laser melting area.

[0019] In some embodiments, the content of C element in the high-temperature alloy powder is exemplarily any one of 0.05 wt%, 0.055 wt%, 0.06 wt%, 0.065 wt%, 0.07 wt%, 0.075 wt%, 0.08 wt%, 0.085 wt%, and 0.09 wt%.

[0020] In some embodiments, the content of Si element in the high-temperature alloy powder is exemplarily any one of 0.20 wt%, 0.21 wt%, 0.22 wt%, 0.23 wt%, 0.24 wt%, 0.25 wt%, 0.26 wt%, 0.27 wt%, 0.28 wt%, 0.29 wt%, 0.30 wt%, 0.31 wt%, 0.32 wt%, 0.33 wt%, 0.34 wt%, and 0.35 wt%.

[0021] In some embodiments, the content of La element in the high-temperature alloy powder is exemplarily any one of 0.05 wt%, 0.055 wt%, 0.06 wt%, 0.065 wt%, 0.07 wt%, 0.075 wt%, 0.08 wt%, 0.85 wt%, 0.09 wt%, 0.095 wt%, and 0.10 wt%.

[0022] Furthermore, the technical parameters of the 3D printing laser selective melting are: substrate preheating temperature is 90-120°C, laser power is 180-250W, scanning speed is 750-1300mm / s, scanning spacing is 0.05-0.09mm, and powder layer thickness is 0.02-0.06mm.

[0023] Furthermore, the inter-layer scanning angle is tilted by 67°.

[0024] In some embodiments, the substrate preheating temperature of the exemplary laser melting area is any one of 90°C, 92°C, 95°C, 96°C, 97°C, 98°C, 100°C, 112°C, 114°C, 115°C, 117°C, 119°C, and 120°C, preferably 95-115°C, and more preferably 98-112°C. The substrate preheating temperature affects the performance of the molded product in two aspects: one is the residual stress. The substrate preheating can reduce the temperature gradient between the molten pool and the surrounding materials, reduce thermal stress, and thus inhibit printing cracks and warping of the molded product; the second is interlayer bonding. The appropriate preheating temperature can improve the bonding strength between the powder layer and the solidified layer and reduce interface defects caused by temperature difference. When the substrate preheating temperature is too low, the residual stress of the molded product is high, the interlayer bonding is weak, and it is easy to crack, while too high a temperature causes the powder to stick together, affecting the reuse of the powder.

[0025] In some embodiments, the laser power of the exemplary laser melting area is any one of 180 W, 185 W, 190 W, 195 W, 200 W, 201 W, 203 W, 205 W, 208 W, 210 W, 211 W, 212 W, 213 W, 214 W, 215 W, 216 W, 217 W, 218 W, 219 W, 220 W, 230 W, 240 W, and 250 W, preferably 205-215 W, and more preferably 210-212 W. When the laser power is insufficient, the alloy powder is not completely melted, resulting in pores and unfused defects; when the power is too high, the material may be evaporated or the spheroidization effect may be triggered, and the splashing of the molten droplets may be aggravated. It is important that the laser power matches the scanning speed to achieve a suitable energy density to reduce the number of alloy defects.

[0026] In some embodiments, the scanning speed of the exemplary laser melting area is any one of 750 mm / s, 800 mm / s, 850 mm / s, 900 mm / s, 950 mm / s, 1000 mm / s, 1100 mm / s, 1200 mm / s, and 1300 mm / s, preferably 950-1100 mm / s. Too fast a scanning speed may lead to defects such as insufficient energy input, poor interlayer bonding, and local non-fusion; too slow a scanning speed may lead to excessive local heat input, which may easily induce greater thermal stress and increase the risk of alloy cracking.

[0027] In some embodiments, the exemplary scanning spacing is any one of 0.05 mm, 0.06 mm, 0.07 mm, 0.08 mm, and 0.09 mm, preferably 0.07-0.08 mm. When the scanning spacing is too large, adjacent melt paths are not fully overlapped, forming pores; when it is too small, some areas are repeatedly heated, increasing the residual stress of the alloy; in addition, the scanning spacing also affects the uniformity of the melt path overlap, indirectly affecting the fatigue strength of the molded product.

[0028] In some embodiments, the exemplary powder layer thickness is any one of 0.02 mm, 0.03 mm, 0.04 mm, 0.05 mm, and 0.06 mm. When the layer thickness is too large, it is difficult for the heat of the lower layer to penetrate the new powder layer, resulting in unfusion and requiring higher energy input; when the layer thickness is too small, the printing efficiency is low, and multiple thermal cycles may deteriorate the alloy structure.

[0029] Furthermore, the preparation method of the molded product also includes a heat treatment step, and the heat treatment procedure is: 1000-1400℃ for 2-8h, cooling to 200℃ with the furnace, and then keeping at 1000-1400℃ for 0.5-2h, and then cooling to 200℃ by gas quenching and taking it out. The thermal stress generated by the sequential rapid melting during 3D printing (especially metal laser melting) will remain in the material, causing deformation, cracking or anisotropy of mechanical properties. By eliminating stress and strengthening by solid solution through heat treatment, the uniformity of the material can be improved and the mechanical properties of the molded product can be improved. However, too high a heat treatment temperature will deteriorate its crystallographic characteristics, resulting in grain coarsening, decreased strength and decreased ductility, etc. When the heat treatment temperature is too low, it is easy to cause the alloy to retain various anisotropic characteristics of the printed state, the alloy solid solution is insufficient, the carbide solid solution and conversion are incomplete, the Laves phase, La-rich phase, and B-rich phase increase the cracking tendency of the alloy, and cannot form a good reinforcement effect, and the mechanical properties fluctuate greatly. Through the two-step heat treatment method, the first step is to fully remelt the M6C carbides and other phases in the structure into the matrix to form fine and dispersed M 23 C6 phase; the second step of heat treatment is implemented to form a uniform austenite phase of appropriate size in the structure to ensure its room temperature and high temperature mechanical properties.

[0030] Preferably, the heat treatment procedure is: keep at 1150-1200°C for 2-8h, cool to 200°C with the furnace, then heat to 1150-1200°C at a rate of 5-15°C / min, keep for 0.5-2h, cool to 200°C with inert gas quenching and take out the sample.

[0031] Preferably, the first step in the heat treatment procedure may be implemented by hot isostatic pressing, with a stress greater than 160 MPa applied to further densify the alloy structure.

[0032] Beneficial effects of the present invention: (1) The present application provides a high-temperature alloy powder suitable for additive manufacturing process, which strictly controls the metal component formula that is different from the existing high-temperature alloy powder, and optimizes the preparation method of the high-temperature alloy powder, the process parameters of 3D printing, and the heat treatment method, effectively solving the molding cracking problem of complex parts in the hot end of aviation and aerospace, and obtaining a 3D printed molding product with good density and excellent high-temperature service performance.

[0033] (2) The composition formula of the high-temperature alloy powder of the present application limits the total amount of carbides, reduces the brittleness of the alloy, and reduces the tendency of the material to crack; reduces the upper limit of the silicon content, reduces the possibility of the formation of Laves phase during the printing process, and increases the crack resistance of the alloy; adds an appropriate amount of rare earth element lanthanum, which can improve the purity of the alloy liquid during the alloy smelting process, making the carbides (such as M 23 C6 phase) is finely dispersed and precipitated to refine the alloy structure and ensure the high temperature tensile strength, yield and durability of the alloy.

[0034] (3) The 3D printing molding process of the present application can produce a suitable energy density by controlling the substrate preheating temperature, laser power, scanning speed, scanning spacing and powder layer thickness to fully melt the raw materials while effectively reducing thermal stress, improving the density of the molded product, avoiding the generation of pores and cracks, and improving the mechanical strength of the molded product.

[0035] (4) The high-temperature alloy powder preparation method of the present application can control the alloy powder to have excellent particle size and sphericity, effectively avoiding the generation of local defects (such as pores and brittle phases) during the 3D printing process. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 : The 3D printed high-temperature alloy powder morphology of Example 1.

[0037] Figure 2 : Microscopic morphology of the 3D printed product of Example 1 in the direction parallel to the deposition substrate.

[0038] Figure 3 : Microscopic morphology of the 3D printed product of Example 1 in the direction perpendicular to the deposition substrate.

[0039] Figure 4 : Backscattered microstructure morphology of the 3D printed product of Example 1 under a scanning electron microscope.

[0040] Figure 5 : Element distribution of the 3D printed product of Example 1.

[0041] Figure 6 : Microscopic morphology of the 3D printed product of Example 2 in the direction parallel to the deposition substrate.

[0042] Figure 7 : Microscopic morphology of the 3D printed product of Example 2 in the direction perpendicular to the deposition substrate.

[0043] Figure 8 : Microscopic morphology of the 3D printed product of Comparative Example 1 in the direction parallel to the deposition substrate.

[0044] Fig. 9: Microscopic morphology of the 3D printed product of Comparative Example 1 in the direction perpendicular to the deposition substrate.

[0045] Fig.10 : Microscopic morphology of the 3D printed product of Comparative Example 2 in the direction parallel to the deposition substrate. DETAILED DESCRIPTION

[0046] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] In one embodiment, a high-temperature alloy powder for 3D printing includes 0.05-0.09wt% of C element, 0.20-0.35wt% of Si element, 0.05-0.10wt% of La element, 21-22wt% of Cr element, 22-23wt% of Ni element, 13-15wt% of W element, ≤1wt% of Fe element, ≤0.015wt% of B element, ≤0.5wt% of Mn element and the balance of Co element.

[0048] The method for preparing the high temperature alloy powder comprises the following steps: melting the alloy raw materials to 1400-1600° C. and fully mixing them, transferring them to an atomization chamber for atomization at a nozzle pressure of 3.0-4.0 MPa, and finally screening and grading the obtained metal powder.

[0049] The preferred melting temperature is 1500-1600°C, the vacuum degree of the atomization chamber is ≥30Pa, and the nozzle pressure is preferably 3.3-3.6MPa.

[0050] The preparation method is further preferably as follows: the alloy is smelted to 1400-1500° C. and the components are mixed uniformly, and then the temperature is increased to 1500-1600° C., the alloy is transferred out of the furnace, and then atomized.

[0051] The particle size of the high temperature alloy powder is 15-150 μm, preferably 15-53 μm.

[0052] The high-temperature alloy powder has a sphericity of not less than 0.92, a powder fluidity of not more than 20s / 50g, and non-metallic inclusions of less than 3 particles / 100g.

[0053] Secondly, this embodiment also provides a laser selective melting 3D printed molded product, the molded product has no printing cracks, a density of ≥99.6%, and a number of pores ≤3 / mm 2, tensile strength ≥ 200MPa, yield strength ≥ 150MPa, elongation ≥ 50% at 980℃, the alloy matrix structure of the molded product is austenite phase, and the grain boundary phase includes M 23 C6 phase, M 23 The C6 phase is dispersed at the grain boundaries.

[0054] The method for preparing the molded product comprises the step of molding the high temperature alloy powder in a laser melting area.

[0055] The technical parameters of the laser melting area are: substrate preheating temperature is 90-120°C, preferably 95-115°C, and more preferably 98-112°C; laser power is 180-250W, preferably 205-215W, and more preferably 210-212W; scanning speed is 750-1300mm / s, preferably 950-1100 mm / s; scanning spacing is 0.05-0.09mm, preferably 0.07-0.08mm; powder layer thickness is 0.02-0.06mm, preferably 0.03-0.04mm; interlayer scanning angle is tilted 67°.

[0056] The preparation method of the molded product also includes a heat treatment step, and the heat treatment procedure is: keep at 1000-1400℃ for 2-8h, cool to 200℃ with the furnace, keep at 1000-1400℃ for 0.5-2h, and air cool. Preferably: keep at 1150-1200℃ for 2-8h, cool to 200℃ with the furnace, then heat to 1150-1200℃ at a rate of 5-15℃ / min, keep for 0.5-2h, use inert gas (such as Ar gas) to cool to 200℃ and take out the sample.

[0057] Example 1

[0058] First, this embodiment provides a high-temperature alloy powder for 3D printing, wherein the components of the high-temperature alloy powder are: 0.052wt% of C element, 0.20wt% of Si element, 0.051wt% of La element, 21.85wt% of Cr element, 22.24wt% of Ni element, 14.35wt% of W element, 0.21wt% of Fe element, 0.005% of B element, 0.36wt% of Mn element and the remainder of Co element.

[0059] The preparation method of the high-temperature alloy powder comprises the following steps: placing the alloy raw material components in a crucible of a vacuum induction furnace for smelting at a smelting temperature of 1500°C for 30 minutes, and heating the raw materials to 1550°C before taking them out of the furnace after fully mixing them. The molten metal is transferred to the atomization chamber through a guide tube, the vacuum degree of the atomization chamber is greater than 30Pa, and atomization and powdering are performed at a nozzle pressure of 3.6MPa. The atomized metal powder is subjected to ultrasonic vibration screening and grading treatment using 250-mesh and 635-mesh sieves to obtain a high-temperature alloy powder with a powder particle size range of 15-53μm. The powder morphology is shown in the attached Figure 1 .

[0060] Secondly, a laser selective melting 3D printed molded product is also provided, and a method for preparing the molded product comprises the following steps: (1) Establish a three-dimensional model of the sample, slice it, and import it into the laser melting area of ​​the EOS-M290 model 3D printer to form the high-temperature alloy powder; The technical parameters of the laser melting area are as follows: substrate preheating temperature is 100°C, laser power is 210W, scanning speed is 1000 mm / s, interlayer scanning angle is tilted 67°, scanning spacing is 0.07mm, and powder layer thickness is 0.04mm.

[0061] (2) The molded product is heat treated. The specific heat treatment procedure is as follows: keep at 1180°C for 4 hours, cool to 200°C in the furnace, then heat to 1180°C at a rate of 10°C / min and keep for 1 hour, quench with inert gas to 200°C and take out for air cooling.

[0062] The metallographic microstructure of the 3D printed product after molding is observed, see attached Figure 2-3 It can be seen that there are very few pores in the molded product, and the number of pores is ≤3 / mm 2 The alloy matrix structure is austenite phase, there is no printing crack, and the density is greater than 99.8%.

[0063] The microstructure analysis and energy spectrum analysis of the 3D printed products after heat treatment are shown in the attached Figure 4-5 It can be seen that the alloy grain structure is equiaxed crystal, and the elements in the crystal are evenly distributed, indicating that the alloy component has obtained a relatively ideal austenite matrix structure after a series of treatments such as powder making, printing, and heat treatment.

[0064] Example 2

[0065] First, this embodiment provides a high-temperature alloy powder for 3D printing, and the components of the high-temperature alloy powder are: the components of the high-temperature alloy powder are: 0.088wt% of C element, 0.34wt% of Si element, 0.099wt% of La element, 21.79wt% of Cr element, 22.52wt% of Ni element, 14.38wt% of W element, 0.24wt% of Fe element, 0.005% of B element, 0.32wt% of Mn element and the remainder of Co element.

[0066] The preparation method of the high-temperature alloy powder comprises the following steps: placing the above alloy raw material components in a crucible of a vacuum induction furnace for smelting at a smelting temperature of 1500°C, and removing the raw materials from the furnace at 1600°C after fully mixing the raw materials. The molten metal is transferred to an atomizing barrel, and argon gas is passed to replace the air in the atomizing barrel. The minimum vacuum degree of the atomizing barrel is 30Pa, and atomization is performed at a nozzle pressure of 3.5MPa. The atomized metal powder is subjected to ultrasonic vibration screening and grading treatment using 250-mesh and 635-mesh sieves to obtain a high-temperature alloy powder with a powder particle size range of 15-53μm.

[0067] Secondly, a laser selective melting 3D printed molded product is also provided, and a method for preparing the molded product comprises the following steps: (1) Establish a three-dimensional model of the sample, slice it, and import it into the laser melting area of ​​the EOS-M290 model 3D printer to form the high-temperature alloy powder; The technical parameters of the laser melting area are as follows: substrate preheating temperature is 115°C, laser power is 215W, scanning speed is 1100 mm / s, interlayer scanning angle is tilted 67°, scanning spacing is 0.07mm, and powder layer thickness is 0.04mm.

[0068] (2) The molded product is heat treated. The specific heat treatment procedure is as follows: keep at 1200℃ for 3 hours, cool to 200℃ in the furnace, then heat to 1200℃ at a rate of 15℃ / min and keep for 0.5 hours, cool to 200℃ with inert gas quenching, and take out and air cool.

[0069] The microstructure of the 3D printed product after molding was observed, see attached Figure 6-7 It can be seen that there are a small number of pores in the molded product, with the number of pores ≤ 3 / mm 2 The alloy matrix structure is austenite phase, there is no printing crack, and the density of the molded product is greater than 99.8%.

[0070] Example 3

[0071] First, this embodiment provides a high-temperature alloy powder for 3D printing, wherein the components of the high-temperature alloy powder are: 0.07wt% of C element, 0.30wt% of Si element, 0.082wt% of La element, 21.79wt% of Cr element, 22.17wt% of Ni element, 14.03wt% of W element, 0.23wt% of Fe element, 0.005% of B element, 0.32wt% of Mn element and the remainder of Co element.

[0072] The preparation method of the high-temperature alloy powder comprises the following steps: placing the above alloy raw material components in a crucible of a vacuum induction furnace for smelting at a smelting temperature of 1400°C, and removing the raw materials from the furnace at 1520°C after fully mixing the raw materials. The molten metal is transferred to an atomizing barrel, and argon gas is passed to replace the air in the atomizing barrel. The minimum vacuum degree of the atomizing barrel is 30Pa, and atomization is performed at a nozzle pressure of 3.3MPa. The atomized metal powder is subjected to ultrasonic vibration screening and grading treatment using 250-mesh and 635-mesh sieves to obtain a high-temperature alloy powder with a powder particle size range of 15-53μm.

[0073] Secondly, a laser selective melting 3D printed molded product is also provided, wherein the molded product has no printing cracks and has a pore number of ≤3 / mm 2 The alloy matrix structure is an austenite phase, and the density of the molded product is greater than 99.6%.

[0074] The method for preparing the molded product comprises the following steps: (1) Establish a three-dimensional model of the sample, slice it, and import it into the laser melting area of ​​the EOS-M290 model 3D printer to form the high-temperature alloy powder; Among them, the technical parameters of the laser melting area are: substrate preheating temperature is 95°C, laser power is 205W, scanning speed is 950mm / s, interlayer scanning angle is tilted 67°; scanning spacing is 0.05mm, and powder layer thickness is 0.06mm.

[0075] (2) The molded product is heat treated. The specific heat treatment procedure is as follows: keep at 1150°C for 8 hours, cool to 200°C in the furnace, then heat to 1150°C at a rate of 5°C / min and keep for 2 hours, cool to 200°C with inert gas quenching, and then take out and air cool.

[0076] Example 4

[0077] First, this embodiment provides a high-temperature alloy powder for 3D printing, wherein the components of the high-temperature alloy powder are: 0.052wt% of C element, 0.20wt% of Si element, 0.051wt% of La element, 20.85wt% of Cr element, 20.24wt% of Ni element, 13.35wt% of W element, 0.21wt% of Fe element, 0.005% of B element, 0.36wt% of Mn element and the balance of Co element.

[0078] The preparation method of the high-temperature alloy powder comprises the following steps: placing the above alloy raw material components in a crucible of a vacuum induction furnace for smelting at a smelting temperature of 1500°C, and removing the raw materials from the furnace at 1530°C after fully mixing the raw materials. The molten metal is transferred to an atomizing barrel, and argon gas is passed to replace the air in the atomizing barrel. The minimum vacuum degree of the atomizing barrel is 30Pa, and atomization is performed at a nozzle pressure of 3.6MPa. The atomized metal powder is subjected to ultrasonic vibration screening and grading treatment using 250 mesh and 635 mesh sieves to obtain a high-temperature alloy powder with a powder particle size range of 15-53μm.

[0079] Secondly, a laser selective melting 3D printed molded product is also provided, wherein the molded product has no printing cracks and has a pore number of ≤3 / mm 2 The alloy matrix structure is an austenite phase, and the density of the molded product is greater than 99.6%.

[0080] The method for preparing the molded product comprises the following steps: (1) Establish a three-dimensional model of the sample, slice it, and import it into the laser melting area of ​​the EOS-M290 model 3D printer to form the high-temperature alloy powder; Among them, the technical parameters of the laser melting area are: substrate preheating temperature is 90°C, laser power is 200W, scanning speed is 900mm / s, interlayer scanning angle is tilted 67°; scanning spacing is 0.08mm, and powder layer thickness is 0.06mm.

[0081] (2) The molded product is heat treated. The specific heat treatment procedure is as follows: keep at 1000°C for 6 hours, cool to 200°C with the furnace, then heat to 1400°C at a rate of 10°C / min and keep for 1 hour, cool to 200°C with inert gas quenching, and take out for air cooling.

[0082] Example 5

[0083] First, this embodiment provides a high-temperature alloy powder for 3D printing, wherein the components of the high-temperature alloy powder are: 0.052wt% of C element, 0.20wt% of Si element, 0.051wt% of La element, 23.82wt% of Cr element, 23.74wt% of Ni element, 15.95wt% of W element, 0.21wt% of Fe element, 0.005% of B element, and 0.36wt% of Mn element.

[0084] The preparation method of the high-temperature alloy powder comprises the following steps: placing the above alloy raw material components in a crucible of a vacuum induction furnace for smelting at a smelting temperature of 1450°C, and removing the raw materials from the furnace at 1550°C after fully mixing the raw materials. The molten metal is transferred to an atomizing barrel, and argon gas is passed to replace the air in the atomizing barrel. The minimum vacuum degree of the atomizing barrel is 30Pa, and atomization is performed at a nozzle pressure of 3.6MPa. The atomized metal powder is subjected to ultrasonic vibration screening and grading treatment using 250 mesh and 635 mesh sieves to obtain a high-temperature alloy powder with a powder particle size range of 15-53μm.

[0085] Secondly, a laser selective melting 3D printed molded product is also provided, wherein the molded product has no printing cracks and has a pore number of ≤3 / mm 2 The alloy matrix structure is an austenite phase, and the density of the molded product is greater than 99.6%.

[0086] The method for preparing the molded product comprises the following steps: (1) Establish a three-dimensional model of the sample, slice it, and import it into the laser melting area of ​​the EOS-M290 model 3D printer to form the high-temperature alloy powder; Among them, the technical parameters of the laser melting area are: substrate preheating temperature is 120°C, laser power is 220W, scanning speed is 1300mm / s, interlayer scanning angle is tilted 67°, scanning spacing is 0.09mm, and powder layer thickness is 0.06mm.

[0087] (2) The molded product is heat treated. The specific heat treatment procedure is as follows: keep at 1400°C for 2 hours, cool to 200°C in the furnace, then heat to 1150°C at a rate of 8°C / min and keep for 2 hours, cool to 200°C with inert gas quenching, and then take out and air cool.

[0088] Comparative Example 1

[0089] This comparative example provides a high-temperature alloy powder and a 3D printed product; they are basically the same as Example 1, except that: the components of the high-temperature alloy powder are: 0.13wt% of C element, 0.40wt% of Si element, 0.12wt% of La element, 21.85wt% of Cr element, 22.24wt% of Ni element, 14.35wt% of W element, 0.21wt% of Fe element, 0.005% of B element, 0.36wt% of Mn element and the balance of Co element.

[0090] The microstructure of the 3D printed product after molding was observed, see attached Figure 8-9 ,It can be seen that there are a small amount of pores in the molded product, but there are a large number of printing cracks, and the alloy density is low.

[0091] Comparative Example 2

[0092] This comparative example provides a high-temperature alloy powder and a 3D printed product; they are basically the same as Example 1, except that: the components of the high-temperature alloy powder are: 0.07wt% of C element, 0.30wt% of Si element, 0.04wt% of La element, 21.85wt% of Cr element, 22.24wt% of Ni element, 14.35wt% of W element, 0.21wt% of Fe element, 0.005% of B element, 0.36wt% of Mn element and the balance of Co element.

[0093] The microstructure of the 3D printed product after molding was observed, see attached Fig.10 , it can be seen that there are a small amount of pores in the molded product and a small amount of printing cracks along the printing direction.

[0094] Comparative Example 3

[0095] This comparative example provides a high-temperature alloy powder and a 3D printed product; it is basically the same as Example 1, except that: the laser power is 260W.

[0096] Comparative Example 4

[0097] This comparative example provides a high-temperature alloy powder and a 3D printed product; it is basically the same as Example 1, except that: the laser power is 260W and the scanning speed is 700mm / s.

[0098] Comparative Example 5

[0099] This comparative example provides a high-temperature alloy powder and a 3D printed molded product; it is basically the same as Example 1, except that: in the heat treatment step of the molded product, the heat treatment procedure is: keep warm at 800°C for 4 hours, cool to 200°C with the furnace, then heat up to 950°C at a rate of 10°C / min and keep warm for 1 hour, cool to 200°C with inert gas quenching, and take out and air cool.

[0100] Performance testing methods and results: The molded products of the embodiment and the comparative example were subjected to a 980°C high temperature tensile mechanical property test. The results are shown in Table 1, where X / Y refers to the direction parallel to the 3D printing substrate, X / Z refers to the deposition direction, i.e., perpendicular to the substrate, Rm represents the tensile strength; R p0.2 The specified plastic extension strength indicates the stress value when the plastic elongation within the extensometer gauge reaches 0.2%; A is the elongation after fracture; and Z is the cross-sectional shrinkage.

[0101] Table 1

[0102] Analysis: It can be seen from the above embodiments and comparative examples that the 3D printed products prepared from the high-temperature alloy powders of Examples 1-2 of the present application have a small amount of pores and no printing cracks, and the 3D printed products of Examples 1-5 have excellent tensile strength, yield strength and elongation at a high temperature of 980°C, which effectively solves the problem of easy cracking of GH5188 alloy printing, and provides a new material and its printing and heat treatment process for the selection and application of additive manufacturing alloys for high-temperature parts in the fields of aerospace and other fields.

[0103] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0104] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A high temperature alloy powder for 3D printing, characterized in that: The components of the high-temperature alloy powder include 0.05-0.09wt% of C element, 0.20-0.35wt% of Si element, 0.05-0.10wt% of La element, 20-24wt% of Cr element, 20-24wt% of Ni element, 13-16wt% of W element, ≤3wt% of Fe element, ≤1.25wt% of Mn element and the balance of Co element; the powder sphericity of the high-temperature alloy powder is not less than 0.92, the powder fluidity is not higher than 20s / 50g, and the non-metallic inclusions are less than 3 particles / 100g.

2. The high temperature alloy powder according to claim 1, characterized in that: The high-temperature alloy powder components include: 0.05-0.09wt% of C element, 0.20-0.35wt% of Si element, 0.05-0.10wt% of La element, 21-22wt% of Cr element, 22-23wt% of Ni element, 13-15wt% of W element, ≤1wt% of Fe element, ≤0.015wt% of B element, ≤0.5wt% of Mn element and the balance of Co element.

3. The method for preparing high temperature alloy powder according to any one of claims 1 to 2, characterized in that: The method comprises the following steps: melting the alloy raw materials to 1400-1600° C. and fully mixing them, transferring them to an atomization chamber and atomizing them with argon gas at a nozzle pressure of 3.0-4.0 MPa, and finally screening and grading the obtained metal powder.

4. The method for preparing high temperature alloy powder according to claim 3, characterized in that: The alloy raw materials are melted to 1400-1500°C and the components are mixed evenly, then the temperature is increased to 1500-1600°C for transfer, and then atomized.

5. The method for preparing high temperature alloy powder according to claim 3, characterized in that: The vacuum degree of the atomization chamber is ≥30Pa, and the nozzle pressure is 3.3-3.6MPa.

6. A 3D printed product, characterized in that: The raw material of the molded product includes the high-temperature alloy powder described in any one of claims 1-2 or the high-temperature alloy powder prepared by any one of the preparation methods of claims 3-5.

7. The 3D printed product according to claim 6, characterized in that: The molded product has no printing cracks, a density of ≥99.6%, and a pore count of ≤3 / mm 2 , tensile strength ≥ 200MPa, yield strength ≥ 150MPa, elongation ≥ 50% at 980℃; the matrix structure of the molded product is austenite phase, and the grain boundary phase includes M 23 C6 phase, M 23 The C6 phase is dispersed at the grain boundaries, where M includes Cr and W.

8. The method for preparing a 3D printed molded product according to claim 6 or 7, characterized in that: The method for preparing the molded product includes the step of molding high-temperature alloy powder in a laser melting area; the technical parameters of the laser melting area are: substrate preheating temperature is 90-120°C, laser power is 180-250W, scanning speed is 750-1300mm / s, scanning spacing is 0.05-0.09mm, and powder laying thickness is 0.02-0.06mm.

9. The method for preparing a 3D printed molded product according to claim 8, characterized in that: The preparation method of the molded product also includes a heat treatment step, and the heat treatment procedure is: keep warm at 1000-1400°C for 2-8h, cool to 200°C with the furnace, keep warm at 1000-1400°C for 0.5-2h, cool to 200°C with inert gas quenching and take out.

10. The method for preparing a 3D printed molded product according to claim 9, characterized in that: The heat treatment procedure is as follows: keep at 1150-1200°C for 2-8h, cool to 200°C with the furnace, then heat to 1150-1200°C at a rate of 5-15°C / min, keep for 0.5-2h, cool to 200°C with inert gas quenching and take out the sample.

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