Nickel-based superalloy with low cracking sensitivity for additive manufacturing

Abstract

Aimed at the cracking problem of nickel-based superalloys for additive manufacturing, the present invention provides a nickel-based superalloy with low cracking sensitivity for additive manufacturing. The microstructure is adjusted and controlled by means of rare-earth microalloying, thereby facilitating the formation of high-density stacking faults, a rare-earth-containing nano second phase, and refined crystal grains and a subcrystal structure in the alloy matrix, increasing the number of isometric crystals, reducing the columnar crystal proportion and the length-to-diameter ratio thereof, decreasing the cracking sensitivity, and greatly improving the strength and plasticity. The method solves the problem of cracking in an additive manufacturing, storage and heat treatment of a nickel-based superalloy, and can be used to prepare a high-performance and crack-free nickel-based superalloy. The present invention has a rational composition design and a simple preparation process, results in a product having excellent performance, and facilitates large-scale industrial production and practical application.

Description

An additively manufactured nickel-based high-temperature alloy with low crack sensitivity Technical Field

[0001] The invention relates to an additively manufactured nickel-based high-temperature alloy with low crack sensitivity, belonging to the field of high-temperature alloys and additive manufacturing. Background Art

[0002] Nickel-based superalloys, with their excellent strength, damage tolerance, and durability, are the preferred structural materials for aerospace hot-end components. However, these alloys are highly susceptible to cracking during additive manufacturing and can even crack during storage and heat treatment.

[0003] A lot of research has been done to address the cracking problem in additively manufactured nickel-based superalloys. Dang [X. Dang, et al. Avoiding cracks in additively manufactured non-weldable directionally solidified Ni-based superalloys, Additive Manufacturing 59 (2022)103095] reduced the crack density and improved the mechanical properties of additively manufactured IN738 nickel-based superalloy by increasing the substrate preheating temperature and reducing the temperature gradient. Xu et al. [J. Xu, et al. Grain refinement and crack inhibition of hard-to-weld Inconel 738 alloy by altering the scanning strategy during selective laser melting, Materials & Design 209 (2021) 109940] used a laser scanning strategy with an interlayer rotation of 67° to produce a local equiaxed structure with almost no cracks. Wei et al. [B. Wei, et al. Microstructure, cracking behavior and mechanical properties of René 104 superalloy fabricated by selective laser melting, Journal of Alloys and Compounds 867 (2021) 158377] optimized the laser power, scanning speed and other process parameters for SLM-fabricated René 104 nickel-based superalloy, improving the relative density and mechanical properties of the formed parts. However, they were unable to eliminate crack defects in the formed parts. Lv et al. [Y Lv, et al. Cracking inhibition behavior and the strengthening effect of TiC particles on the CM247LC superalloy prepared by selective laser melting, Materials Science & Engineering A858 (2022) 144119] eliminated cracks in the SLM-fabricated CM247LC superalloy by adding nano-TiC particles, significantly improving the alloy's strength.Tomus et al. [D. Tomus, et al. Effect of minor alloying elements on crack-formation characteristics of Hastelloy-X manufactured by selective laser melting, Additive Manufacturing 16 (2017) 65-72.] reduced the Si, C, and Mn content in Hastelloy-X alloy, improving the alloy microstructure, effectively suppressing cracking, and enhancing the alloy's mechanical properties. Chinese patent CN202010891107.5 discloses a method for preventing cracking in selective laser-melted nickel-based superalloys. By reducing the low-melting-point phase-forming elements Zr and B in the nickel-based superalloy and adjusting the total Al and Ti content in the alloy to ≤4.5wt%, a component with high relative density, no crack defects, and excellent mechanical properties was produced. Chinese patent CN202010891045.8 discloses a method for eliminating cracks in 3D-printed nickel-based superalloys. Addressing the problem of cracking in 3D-printed γ′-precipitation-strengthened nickel-based superalloys, the method proposes using RE microalloying to reduce the crack sensitivity of 3D-printed γ′-precipitation-strengthened nickel-based superalloys, broaden the 3D printing process window, inhibit cracking during 3D printing, significantly improve the strength and ductility of formed parts, and effectively prevent cracking during subsequent processing, such as storage cracking between processes and subsequent heat treatment. The resulting γ′-precipitation-strengthened nickel-based superalloy, René 104, exhibits no cracks and a relative density exceeding 99.4%. The as-printed samples exhibit yield strength and tensile strength of 935 MPa and 1256 MPa, respectively, with an elongation exceeding 14.0%. Technical issues

[0004] The present invention proposes to control the microstructure through composite microalloying of RE elements, introducing high-density stacking faults and Lomer-Cottrell locks for the first time into the microstructure of a nickel-based high-temperature alloy sensitive to cracking in additive manufacturing. At the same time, the RE elements react with the Al element to form a second phase containing RE, which refines the grains, increases the number of equiaxed crystals, and reduces the number of columnar crystals and the aspect ratio. The present invention achieves alloy microstructure control, reduces cracking sensitivity, and simultaneously improves the strength and plasticity of the alloy, completely eliminating additive manufacturing cracks in nickel-based high-temperature alloys, and solving the problems of forming, storage, and post-processing cracking in additively manufactured nickel-based high-temperature alloys. A nickel-based high-temperature alloy that is fully suitable for additive manufacturing has been designed. Technical Solutions

[0005] In order to solve the problems of poor formability and processability of nickel-based high-temperature alloys in additive manufacturing, the present invention is based on the previous research of the inventor's team (CN202010891045.8). For the first time, a high-strength and plastic nickel-based high-temperature alloy suitable for additive manufacturing is designed. High-density stacking faults and Lomer-Cottrell locks are formed in the additive manufacturing sample, without crack defects, and the additive manufacturing processability is good, with higher strength and plasticity.

[0006] The present invention provides a high-strength and plastic nickel-based high-temperature alloy for additive manufacturing. Using an RE-containing master alloy as a raw material, the nickel-based high-temperature alloy is subjected to RE microalloying to induce the alloy to form high-density stacking faults and Lomer-Cottrell locks, thereby reducing cracking sensitivity and simultaneously improving strength and plasticity to prepare a completely crack-free nickel-based high-temperature alloy.

[0007] The present invention provides a high-strength and plastic nickel-based high-temperature alloy for additive manufacturing. The nickel-based high-temperature alloy forms a second phase containing RE nano-scale and a fine subgrain structure, the number of equiaxed crystals is significantly increased, and the proportion of columnar crystals and their aspect ratio are greatly reduced.

[0008] The present invention discloses a high-strength and high-plasticity nickel-based high-temperature alloy for additive manufacturing, wherein the nickel-based high-temperature alloy has high-density stacking faults and Lomer-Cottrell locks; the high-density stacking faults refer to: the stacking fault density in the alloy is greater than 1.8×10 11 cm -2 .

[0009] The present invention discloses a high-strength and plastic nickel-based high-temperature alloy for additive manufacturing, which has low cracking sensitivity, does not produce cracks during the alloy preparation process, and does not crack during subsequent storage and heat treatment processes.

[0010] The material component structure of the present invention is reasonably designed, the production process requirements are reduced, and the prepared alloy parts have high relative density and no crack defects, which provides the necessary conditions for its industrialization.

[0011] Compared with Chinese patent CN202010891045.8, the additive manufacturing process performance and mechanical properties of the nickel-based high-temperature alloy provided by the present invention are significantly improved.

[0012] The present invention provides a high-strength and plastic nickel-based high-temperature alloy for additive manufacturing. The nickel-based high-temperature alloy is manufactured by additive manufacturing to obtain a printed product, and the printed product is subjected to heat treatment to obtain a heat-treated product.

[0013] The present invention provides a high-strength and plastic nickel-based high-temperature alloy for additive manufacturing, which comprises the following components in percentage by mass:

[0014] The matrix high temperature alloy content is 99.80-99.92wt.%;

[0015] The RE element content is 0.08-0.20 wt.%, preferably 0.12-0.20 wt.%, and further preferably 0.14 wt.%;

[0016] The base high-temperature alloy is selected from one of IN738LC, CM247LC, CMSX-4, Hastelloy X, and René 104, preferably René 104.

[0017] The RE element is selected from at least one of Sc, Y, La, and Ce, preferably Sc and Y in a mass ratio of 1:1;

[0018] The content of trace elements in the nickel-based high-temperature alloy matrix and rare earth elements is composed of a mass ratio of 13:13-14, and the trace elements are Zr, B, C and other elements.

[0019] The present invention provides a high-strength and plastic nickel-based high-temperature alloy for additive manufacturing, which is prepared by the following steps:

[0020] Step 1: preparing a nickel-containing master alloy A from a high-melting-point element in a nickel-based high-temperature alloy, wherein the high-melting-point element is selected from at least one of Nb, Ta, W, Mo, Cr, and Zr, and the melting temperature of the nickel-containing master alloy A is less than 1600°C;

[0021] The RE element is designed to be an intermediate alloy B; the absolute value of the difference between the melting temperature of alloy B and the melting temperature of alloy A is less than or equal to 200°C;

[0022] Step 2: Using master alloys A and B and other designed components as raw materials, prepare atomized nickel-based high-temperature alloy powder; the atomized alloy powder is sieved to obtain a standby alloy powder for additive manufacturing;

[0023] Step 3: Use the spare alloy powder as raw material to perform additive manufacturing (3D printing) to obtain a printed product.

[0024] The present invention discloses a high-strength and plastic nickel-based high-temperature alloy for additive manufacturing. In combination with a binary alloy phase diagram, W, Ta, Nb, Mo, and Ni metal elements with relatively high melting points are weighed; and Ni-W, Ni-Ta, Ni-Nb, and Ni-Mo binary master alloys are prepared with metallic nickel by suspension melting or arc melting to obtain the nickel-containing alloy A.

[0025] Alloy B is prepared by the following steps: according to the binary alloy phase diagram, according to the operation content in step 1, rare earth elements are added to molten metal Al liquid to prepare Al-RE master alloy B containing rare earth elements;

[0026] During the preparation process, smelting is carried out under protective gas conditions;

[0027] The protective gas is the inert gas, which is helium, argon, or a mixture of argon and helium, with a purity of 99.99 wt.%, wherein the oxygen content is less than 0.0001 wt.%.

[0028] The present invention provides a high-strength and plastic nickel-based high-temperature alloy for additive manufacturing, wherein the melting temperature of alloy B minus the melting temperature of alloy A is less than or equal to 200°C, preferably less than or equal to 150°C.

[0029] The present invention discloses a high-strength and plastic nickel-based high-temperature alloy for additive manufacturing. The atomized alloy powder for additive manufacturing is prepared by an argon atomization method or a plasma rotating electrode atomization method. The particle size of the powder ranges from 10 to 53 μm.

[0030] The present invention provides a high-strength and plastic nickel-based high-temperature alloy for additive manufacturing, wherein the additive manufacturing technology is selected from one of laser powder bed fusion (LPBF), electron beam melting, or laser coaxial powder feeding laser forming.

[0031] During additive manufacturing, in order to ensure sufficient laser energy input, increase the fluidity of the molten metal in the molten pool, promote the uniform distribution of elements in the molten metal and the formation of a uniform molten pool structure, the laser beam spot diameter used is 80-100 μm.

[0032] During additive manufacturing, the substrate preheating temperature is controlled to be 150-200°C, the scanning interlayer rotation angle is controlled to be 67°, the laser input power is controlled to be 200-400 W, preferably 320-400 W, and more preferably 345-355 W, the scanning speed is controlled to be 200-1200 mm / s, preferably 750-1200 mm / s, and more preferably 780-820 mm / s, the overlap spacing is controlled to be 70-120 μm, and the powder layer thickness is controlled to be 35-60 μm.

[0033] In the present invention, the protective atmosphere used in additive manufacturing is preferably an argon atmosphere, and scanning is performed using a serpentine scanning method.

[0034] The present invention provides a high-strength and plastic nickel-based high-temperature alloy for additive manufacturing, wherein the average grain size of the printed product is less than 68.3 μm.

[0035] The average size of subcrystals in the printed product is less than 420 nm.

[0036] This invention uses laser powder bed fusion forming, with the substrate temperature adjusted to 170°C, the inter-layer rotation angle set to 67°, the laser input power to 350 W, the scanning speed to 800 mm / s, the overlap spacing to 90 μm, and the powder layer thickness to 40 μm. The laser spot diameter used was 100 μm, the scanning method was serpentine scanning, and argon gas was introduced to produce crack-free prints. The resulting prints had a relative density of 99.81%, a room-temperature yield strength and tensile strength of 1059 MPa and 1405 MPa, respectively, and an elongation of 28.8%.

[0037] The present invention discloses a high-strength and plastic nickel-based high-temperature alloy for additive manufacturing. The alloy is stored indoors at normal temperature and pressure for 730 days, and a long-term storage sample is obtained without cracks.

[0038] The present invention provides a high-strength and plastic nickel-based high-temperature alloy for additive manufacturing. The printed product is heat-treated at a temperature greater than or equal to 1170°C, preferably 1170-1200°C, to obtain a heat-treated product without cracks.

[0039] The present invention provides a high-strength and plastic nickel-based high-temperature alloy for additive manufacturing. The heat treatment time of the printed product is 1 to 8 hours, preferably 1 to 6 hours, more preferably 2 to 4 hours, and even more preferably 2 to 3 hours.

[0040] The present invention discloses a high-strength and plastic nickel-based high-temperature alloy for additive manufacturing. The printed product has no cracking phenomenon. The product has a yield strength of 1012 to 1060 MPa, preferably 1040 to 1060 MPa, a tensile strength of 1370 to 1410 MPa, preferably 1380 to 1410 MPa, and an elongation of 23 to 29%, preferably 27.6 to 28.8%.

[0041] After the printed product is heat treated at 1170-1180°C, the yield strength of the obtained heat-treated product is 1115-1280 MPa, preferably 1124-1280 MPa, the tensile strength is 1510-1585 MPa, and the elongation is 14-20%, preferably 18-20%; the obtained heat-treated product has no cracking phenomenon. Beneficial effects

[0042] This invention, for the first time, designs a high-strength and high-ductility nickel-based superalloy for additive manufacturing (AM) with a high density of stacking faults and Lomer-Cottrell locks. By inducing high-density stacking faults and Lomer-Cottrell locks in the alloy through RE microalloying, the invention achieves a significant increase in the strength and ductility of the AM nickel-based superalloy, as well as significant improvements in formability. All nickel-based superalloy parts produced using various AM process parameters remain crack-free in all conditions, including AM, long-term storage, and heat treatment. Stress relief annealing is not required, and cracking does not occur even after direct high-temperature heat treatment or long-term storage.

[0043] (1) The present invention proposes to use a low-melting-point intermediate alloy as a raw material to prepare nickel-based high-temperature alloy powder for additive manufacturing, thereby reducing the RE element loss during the powder preparation process and obtaining a crack-free nickel-based high-temperature alloy prepared by additive manufacturing.

[0044] (2) The present invention forms a nano-second phase containing RE in a nickel-based high-temperature alloy through RE microalloying. The RE-containing second phase acts as a nucleating agent, refines the grain and subgrain structure, increases the number of equiaxed crystals, inhibits the growth of columnar crystals, and reduces the proportion of columnar crystals and their aspect ratio.

[0045] (3) The product obtained by the present invention forms high-density stacking faults and Lomer-Cottrell locks, nano-second phases, fine subgrain structures, equiaxed crystals, and low aspect ratio columnar crystals, which greatly reduce the cracking sensitivity of the alloy and simultaneously improve the strength and plasticity of the alloy.

[0046] (4) The nickel-based high-temperature alloy powder prepared by the present invention by combining the designed components with the powder making process has no cracks in the printed parts prepared using various additive manufacturing process parameters, effectively suppressing the cracking of the alloy during additive manufacturing, long-term storage and heat treatment.

[0047] (5) The nickel-based high-temperature alloy designed by the present invention does not need to undergo low-temperature stress relief annealing treatment and can be directly subjected to high-temperature heat treatment without cracking. While its strength is greatly improved, it can also maintain good plasticity.

[0048] In summary, the present invention, a high-strength and plastic nickel-based high-temperature alloy for additive manufacturing, proposes for the first time the use of a low-melting-point master alloy to add RE microalloying elements, inducing the alloy to form high-density stacking faults and Lomer-Cottrell locks, as well as RE-containing second phases, fine grains and subgrains, increasing equiaxed crystals, inhibiting the growth of columnar crystals, reducing the proportion of columnar crystals and their aspect ratio, achieving a significant simultaneous improvement in the alloy's strength and plasticity, reducing the alloy's cracking sensitivity, and ensuring that the alloy is crack-free in all states, including additive manufacturing, long-term storage, and heat treatment. The present invention completely eliminates the cracking problem of nickel-based high-temperature alloy additive manufacturing and subsequent processes, providing a new method for developing high-performance nickel-based high-temperature alloys for additive manufacturing and other alloy materials for additive manufacturing. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] FIG1 is a metallographic microstructure of a nickel-based high-temperature alloy formed by LPBF in Example 1;

[0050] FIG2 is a metallographic microstructure of the nickel-based high-temperature alloy prepared using all series of process parameters in Example 2;

[0051] FIG3 is a TEM image of the microstructure of the formed part with the optimal process parameters in Example 2;

[0052] FIG4 is a metallographic microstructure diagram of the formed part in Example 3;

[0053] FIG5 is a metallographic microstructure of the sample after 730 days of storage in Example 4;

[0054] FIG6 is a metallographic microstructure of the sample after heat treatment in Example 5;

[0055] FIG7 is a metallographic microstructure of the sample after heat treatment in Example 6;

[0056] FIG8 is a metallographic microstructure of the sample after heat treatment in Example 7;

[0057] FIG9 is a metallographic microstructure of the sample after heat treatment in Example 8;

[0058] FIG10 is a metallographic microstructure of the sample in Comparative Example 1;

[0059] FIG11 is a metallographic microstructure diagram of the sample in Comparative Example 2. Modes for Carrying Out the Invention

[0060] The alloy powder used in the additive manufacturing (including LPBF) of the present invention is prepared by the following steps:

[0061] Step 1: preparing a nickel-containing master alloy A from a high-melting-point element in a nickel-based high-temperature alloy, wherein the high-melting-point element is selected from at least one of Nb, Ta, W, Mo, Cr, and Zr, and the melting temperature of the nickel-containing master alloy A is less than 1600°C;

[0062] The RE element is designed to be an intermediate alloy B; the absolute value of the difference between the melting temperature of alloy B and the melting temperature of alloy A is less than or equal to 200°C;

[0063] Step 2: Using master alloys A and B and other designed components as raw materials, atomized nickel-based high-temperature alloy powder is prepared according to the designed composition; the atomized alloy powder is sieved to obtain a spare alloy powder for additive manufacturing.

[0064] Example 1:

[0065] A nickel-based superalloy powder (measured composition) with a total rare earth RE addition of 0.13 wt.% was prepared by argon atomization. The alloy powder for LPBF was obtained after sieving. The specific composition of the alloy powder for LPBF is (wt.%): Co: 20.6%; Cr: 13%; Al: 3.4%; Ti: 3.9%; Mo: 3.8%; W: 2.1%; Ta: 2.4%; Nb: 0.9%; Zr: 0.05%; B: 0.03%; C: 0.05%; RE: 0.13 wt.% (RE is composed of Sc and Y in a mass ratio of 1:1); the balance is Ni.

[0066] The particle size of the nickel-based high-temperature alloy powder used for LPBF forming is 10-53 μm;

[0067] LPBF forming was performed using a substrate preheating temperature of 170°C. The inter-scanning layer rotation angle was set to 67°, the laser input power was 320 W, the scanning speed was 800 mm / s, the overlap spacing was 90 μm, and the powder layer thickness was 40 μm. The laser spot diameter was 100 μm, and the forming scanning method was a serpentine scan. Argon gas was introduced into the working chamber until the oxygen content was below 100 ppm before printing began. The microstructure of the formed part is shown in Figure 1. As can be seen, only a few pores were observed within the printed part, with no cracks. The printed part (i.e., as-printed) had a relative density of 99.7% and was crack-free. The room-temperature yield strength and tensile strength were 1012 MPa and 1375 MPa, respectively, and the elongation was 23.2%.

[0068] Example 2:

[0069] A nickel-based superalloy powder (measured composition) with a total rare earth (RE) addition of 0.14 wt.% was prepared using argon atomization. Sieving yielded an alloy powder for LPBF. The specific composition (wt.%) of the alloy powder for LPBF is: Co: 20.6%; Cr: 13%; Al: 3.4%; Ti: 3.9%; Mo: 3.8%; W: 2.1%; Ta: 2.4%; Nb: 0.9%; Zr: 0.07%; B: 0.03%; C: 0.05%; RE: 0.14 (RE consists of Sc and Y in a mass ratio of 1:1); the balance is Ni. A nickel-based superalloy powder (measured composition) with a total rare earth (RE) addition of 0.14 wt.% was prepared using the same powder preparation method as in Example 1.

[0070] The sieved RE microalloyed alloy powder was dried in a vacuum drying oven at 120 ºC for 4 h. Argon or nitrogen was introduced into the working chamber until the oxygen content was less than 100 ppm. After the substrate was heated to 170 ºC, the preparation of the RE microalloyed René 104 nickel-based superalloy bulk sample was completed.

[0071] The process parameters were: substrate preheat temperature at 170°C, inter-slice rotation angle at 67°, laser powers of 200, 270, 320, 350, and 360 W, and scanning speeds of 600, 700, 800, 900, 1000, and 1100 mm / s. Samples printed using various process parameters showed no crack defects, demonstrating the alloy's low crack susceptibility.

[0072] in:

[0073] When the process parameters are 320 W and 800 mm / s, the yield strength and tensile strength of the printed sample are 1012 MPa and 1375 MPa, respectively, and the elongation is 25.2%.

[0074] When the process parameters are 350 W and 800 mm / s, the yield strength and tensile strength of the printed sample are 1059 MPa and 1405 MPa, respectively, and the elongation is 28.8%.

[0075] When the process parameters are 360 ​​W and 800 mm / s, the yield strength and tensile strength of the printed sample are 1042 MPa and 1387 MPa, respectively, and the elongation is 27.6%.

[0076] The microstructure metallographic characterization of the nickel-based high-temperature alloy prepared by all series of process parameters in Example 2 is shown in Figure 2. As can be seen from Figure 2, no crack defects were observed in the nickel-based high-temperature alloy formed parts prepared by all process parameters in this example, and the nickel-based high-temperature alloy formed parts had excellent mechanical properties.

[0077] Figure 3 shows the microstructure of the formed part produced using the optimal process parameters (i.e., 350 W, 800 mm / s). Figure 3 shows the presence of a high density of stacking faults and Lomer-Cottrell locks, a uniform and fine subgrain structure, and a large number of nano-spherical second phases. The stacking fault density was determined by statistical analysis of the TEM bright-field images and was found to be greater than 1.8×10 11 cm -2 .

[0078] Example 3:

[0079] Using the alloy powder prepared in Example 2 as raw material, printing was performed using the same forming parameters as in Comparative Example 1 in Chinese patent CN202010891045.8. Specifically, the laser spot diameter was 70 μm, the laser power was 400 W, the laser scanning rate was 1200 mm / s, the laser overlap spacing was 90 μm, the powder layer thickness was 30 μm, and a strip scanning strategy was used, with the laser scanning direction rotated 67° between layers. The microstructure of the resulting print is shown in Figure 4. As can be seen from Figure 4, no cracks were observed in the prepared sample.

[0080] After testing, the prepared RE microalloyed René 104 alloy (printed state) has a relative density of 99.5%, a room temperature yield strength of 986 MPa, a tensile strength of 1312 MPa, and an elongation of 19.6%.

[0081] The present invention employs the additive manufacturing process parameters that exhibit cracking and the worst part performance in Comparative Example 1 of Chinese Patent CN202010891045.8, yet still produces high-quality, crack-free parts with excellent mechanical properties. This demonstrates that the powder production process designed in the present invention can reduce the cracking sensitivity of γ′-phase-reinforced nickel-based superalloys and effectively suppress LPBF cracking. It also demonstrates that the present invention offers a wider printing window.

[0082] Example 4:

[0083] The printed product obtained using the optimal printing parameters (350 W and 800 mm / s) in Example 2 was stored indoors at room temperature and pressure for 730 days. Figure 5 shows the microstructure and metallographic characteristics of the sample after 730 days of storage. Figure 5 demonstrates that the nickel-based superalloy prepared by the present invention exhibits no cracking after prolonged storage at room temperature and pressure.

[0084] Embodiment 5:

[0085] The printed product obtained with the optimal printing parameters (350 W and 800 mm / s) of Example 2 was subjected to the following heat treatment process:

[0086] The printed product was directly heated to 1170°C for 2 hours and then air-cooled to obtain a heat-treated nickel-based superalloy. The microstructure and metallographic characteristics of the heat-treated nickel-based superalloy are shown in Figure 6. Figure 6 shows that after heat treatment, the nickel-based superalloy obtained in this example showed no cracking.

[0087] Testing of the mechanical properties of the heat-treated nickel-based superalloy revealed yield strength of 1124 MPa, tensile strength of 1511 MPa, and elongation of 14%. The overall mechanical properties are significantly superior to those of alloys of the same grade and type.

[0088] Example 6:

[0089] Other conditions were identical to those in Example 5, with the exception that the printed product was held at 1170°C for 3 hours and then air-cooled to obtain a heat-treated nickel-based superalloy. The microstructure and metallographic characterization of the resulting heat-treated nickel-based superalloy are shown in Figure 7. Figure 7 shows that no cracking was observed in the heat-treated nickel-based superalloy.

[0090] The mechanical properties of the heat-treated nickel-based high-temperature alloy were tested, and the results showed that the yield strength was 1277 MPa and the tensile strength was 1583 MPa, with significantly improved strength and elongation greater than 18.6%. Its comprehensive mechanical properties were significantly better than those of alloys of the same grade and type.

[0091] Embodiment seven:

[0092] All other conditions were identical to those in Example 5, with the exception that the printed product was held at 1170°C for 4 hours and then air-cooled to obtain a heat-treated nickel-based superalloy. The microstructure and metallographic characterization of the resulting heat-treated nickel-based superalloy are shown in Figure 8. Figure 8 shows that no cracking occurred in the heat-treated nickel-based superalloy.

[0093] The mechanical properties of the heat-treated nickel-based high-temperature alloy were tested, and the results showed that the yield strength was 1119 MPa and the tensile strength was 1501 MPa. Its strength was significantly improved, and the elongation was greater than 13%. Its comprehensive mechanical properties were significantly better than those of alloys of the same grade and type.

[0094] Example 8

[0095] All other conditions were identical to those in Example 5, with the exception that the printed product was held at 1200°C for 3 hours and then air-cooled to obtain a heat-treated nickel-based superalloy. The microstructure and metallographic characterization of the resulting heat-treated nickel-based superalloy are shown in Figure 9. Figure 9 shows that the resulting nickel-based superalloy exhibited no cracking.

[0096] The mechanical properties of the obtained nickel-based high-temperature alloy were tested, and the results showed that the alloy had a yield strength of 1059 MPa and a tensile strength of 1477 MPa, with significantly improved strength and an elongation greater than 19.8%. Its comprehensive mechanical properties were significantly better than those of alloys of the same grade and type.

[0097] Comparative Example 1:

[0098] Prints were prepared using the raw materials and printing parameters described in Example 1 of Chinese Patent CN 202010891045.8 and then stored indoors at room temperature and pressure for 730 days. Figure 10 shows the microstructure of the sample after 730 days of storage. This figure shows the presence of high-density, large-scale cracks after prolonged storage.

[0099] Comparative Example 2:

[0100] Using the alloy powder from Example 3 of Chinese Patent CN 202010891045.8, and the optimal printing parameters from Example 2 of the present invention, a RE microalloyed René 104 nickel-based superalloy print was produced. The print was then subjected to a high-temperature heat treatment at 1170°C for 3 hours. The microstructure and metallographic characterization of the product obtained after the high-temperature heat treatment are shown in Figure 11.

[0101] As shown in Figure 11, the best-performing molded part from Chinese patent CN 202010891045.8 exhibited cracking after high-temperature heat treatment. However, the samples prepared using the present invention (Examples 5-8) did not exhibit this phenomenon and maintained a good combination of strength and plasticity. This demonstrates that the samples prepared using the present invention possess excellent high-temperature stability.

Claims

1. An additive manufacturing nickel-based superalloy with low cracking sensitivity, characterized in that: In the microstructure of the nickel-based superalloy, there are high-density stacking faults formed, and it includes the following components by mass percentage: Using the nickel-based superalloy as the matrix, adding rare earth RE to the matrix; The matrix superalloy is selected from one of René104, IN738LC, CM247LC, CMSX-4, Hastelloy X, and preferably René 104; The RE element is selected from at least one of Sc, Y, La, Ce, and is preferably composed of Sc and Y in a mass ratio of 1:1; The content of the matrix superalloy is 99.80 - 99.92 wt.%; The content of the RE element is 0.08 - 0.20 wt.%, preferably 0.12 - 0.20 wt.%, and more preferably 0.14 wt.%; The content of trace elements in the nickel-based superalloy matrix and the rare earth element are composed in a mass ratio of 13:13 - 14, and the trace elements are elements such as Zr, B, C, etc.; The nickel-based superalloy is prepared by additive manufacturing to obtain a as-printed product, and the as-printed product is heat-treated to obtain a heat-treated product; The high-density stacking fault refers to a stacking fault density greater than 1.8×10 11 cm -2 .

2. The low-cracking-sensitivity nickel-based superalloy for additive manufacturing according to claim 1, wherein: It includes the following preparation steps: Step 1: Prepare a nickel-containing alloy A from the high-melting-point elements in the nickel-based superalloy. The high-melting-point elements are selected from at least one of Nb, Ta, W, Mo, Cr, Zr, and the melting temperature of the nickel-containing alloy A is less than or equal to 1600 ºC; Design the RE element and the other elements of the nickel-based superalloy into alloy B; the difference between the melting temperature of alloy A and the melting temperature of alloy B is less than or equal to 200 ºC; Step 2: Using the master alloys A, B and other designed components as raw materials, prepare an atomized nickel-based superalloy powder; the atomized alloy powder is screened to obtain a spare alloy powder for additive manufacturing; Step 3: Using the spare alloy powder as the raw material, carry out additive manufacturing (3D printing) to obtain an as-printed product.

3. An additive manufacturing nickel-based superalloy with low cracking sensitivity according to claim 2, characterized in that: The nickel-containing alloy A is prepared through the following steps: Combining the binary alloy phase diagram, weigh the metallic elements of W, Ta, Nb, Mo, Zr, Cr and Ni with higher melting points; adopt the method of levitation melting or arc melting to prepare Ni-W, Ni-Ta, Ni-Nb, Ni-Mo, Ni-Cr, Ni-Zr binary master alloys A with metallic nickel respectively; Alloy B is prepared through the following steps: According to the binary alloy phase diagram, according to the operation content in Step 1, prepare an Al-RE binary alloy from the low-melting-point Al element and the RE element; add the RE element to the molten metal Al liquid to prepare an Al-RE master alloy B containing the RE element; During the preparation process, the melting is carried out in a protective atmosphere; The protective gas is an inert gas helium, argon, or an argon-helium mixed gas, with a purity of 99.99 wt%, and the oxygen content is less than 0.0001 wt%; 4. The additive manufacturing nickel-based superalloy with low cracking sensitivity according to claim 2, characterized in that: The melting temperature of alloy B minus the melting temperature of alloy A is less than or equal to 200 ºC, preferably less than or equal to 150 ºC; the particle size range of the spare alloy powder is 10 - 53 μm; 5. An additive manufacturing nickel-based superalloy with low cracking sensitivity according to claim 2, characterized in that: The additive manufacturing technology is selected from one of laser powder bed fusion, electron beam melting, and coaxial powder feeding laser forming; During additive manufacturing, the spot diameter of the laser beam used is 80 - 120 μm; During additive manufacturing, control the substrate preheating temperature to 150 - 200 °C, control the scanning layer rotation angle to 67°, control the laser input power to 200 - 400 W, control the scanning speed to 200 - 1200 mm / s, control the overlap spacing to 70 - 120 μm, and control the powder layer thickness to 35 - 60 μm.

6. An additive manufacturing nickel-based superalloy with low cracking sensitivity according to claim 2, characterized in that: Perform heat treatment at a temperature of 1170 °C or higher, preferably 1170 - 1200 °C, to obtain a heat-treated product.

7. An additive manufacturing nickel-based superalloy with low cracking sensitivity according to any one of claims 2-6, characterized in that: The as-printed product has no cracking phenomenon. The yield strength of the product is 1012 - 1060 MPa, the tensile strength is 1370 - 1410 MPa, and the elongation is 23 - 29%; After heat-treating the as-printed product at 1170 - 1180 °C, the yield strength of the obtained heat-treated product is 1115 - 1280 MPa, the tensile strength is 1510 - 1585 MPa, and the elongation is 14 - 20%; the obtained heat-treated product has no cracking phenomenon.

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