Crack-resistant Fe-Cr-Ni based precipitation-strengthened high-temperature alloy and its preparation method and application

Abstract

The present invention belongs to the field of metal additive manufacturing technology, and relates to a crack-resistant Fe-Cr-Ni-based precipitation-strengthened high-temperature alloy, its preparation method and application. The present invention achieves crack-free and high-densification of Fe-Cr-Ni-based precipitation-strengthened high-temperature alloy formed by selective laser melting by regulating the content of C, Si and Co elements, combined with specific composition design. The Fe-Cr-Ni-based precipitation-strengthened high-temperature alloy prepared by the method of the present invention has excellent mechanical properties, with a room temperature yield strength of ≥1103MPa, a tensile strength of ≥1197MPa, and an elongation of ≥9.2%; a high-temperature yield strength of ≥842MPa, a tensile strength of ≥949MPa, and an elongation of ≥10.1% at 650℃.

Description

Technical Field

[0001] The present invention belongs to the technical field of metal additive manufacturing, and relates to a Fe-Cr-Ni based high temperature alloy produced by selective laser melting, and in particular to a crack-resistant Fe-Cr-Ni based precipitation-strengthened high temperature alloy, and a preparation method and application thereof. Background Art

[0002] Due to their excellent high-temperature strength, oxidation resistance, and corrosion resistance, Fe-Cr-Ni-based precipitation-strengthened superalloys are widely used in high-temperature environments such as turbine blades for aircraft engines below 900°C. However, existing Fe-Cr-Ni-based precipitation-strengthened superalloy compositions, such as K438 alloy, are suitable for casting. However, during the selective laser melting process, high cooling rates and concentrated thermal stresses can easily lead to microcracks, resulting in low density of the formed parts, seriously affecting the mechanical properties of the parts and product quality and safety. In existing technologies, cracking is usually alleviated by adding rare earth elements (such as Ce and Y) or adjusting process parameters. However, excessive rare earth elements can form brittle phases, which in turn exacerbate the cracking tendency and make post-processing (such as hot isostatic pressing) expensive and inefficient.

[0003] In view of this, the present invention is proposed. Summary of the Invention

[0004] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a crack-resistant Fe-Cr-Ni based precipitation-strengthened high-temperature alloy and its preparation method and application, so as to solve the problem of cracking in the existing Fe-Cr-Ni based precipitation-strengthened high-temperature alloy powder forming.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] On the one hand, the present invention provides a crack-resistant Fe-Cr-Ni based precipitation-strengthened high-temperature alloy powder, which is composed of the following components, by weight percentage: Cr: 15~15.5wt.%, Co: 9.5~10wt.%, W: 2.4~3wt.%, C: 0.05~0.08wt.%, Al: 3.2~3.7wt.%, Ti: 3~3.5wt.%, Nb: 0.6~1.1wt.%, B: 0.01~0.02wt.%, Zr: 0.05~0.15wt.%, Fe: 0.5~1.5wt.%, Si: 0.05~0.1wt.%, and the total content of impurity elements is ≤0.01wt.%, and the balance is Ni.

[0007] Specifically, the particle size of the high-temperature alloy powder is 15-53 μm, the average particle size is ≤45 μm, the oxygen content is <100 ppm, and the apparent density is ≥4.47 g / cm 3 , tap density ≥5.28g / cm 3 .

[0008] On the other hand, the present invention also provides a method for preparing a crack-resistant Fe-Cr-Ni based precipitation-strengthened high-temperature alloy, comprising the following steps:

[0009] Step 1: pretreating the crack-resistant Fe-Cr-Ni-based precipitation-strengthened high-temperature alloy powder described above in part or in whole to obtain a standby high-temperature alloy powder;

[0010] Step 2: performing selective laser melting on the prepared high-temperature alloy powder to produce a dense master alloy part;

[0011] Step 3: heat-treating the dense intermediate alloy product to obtain a target high-temperature alloy product.

[0012] Furthermore, in step 1, the preparation process of the crack-resistant Fe-Cr-Ni based precipitation-strengthened high-temperature alloy powder is as follows:

[0013] The raw materials of each component are weighed according to the required weight percentage, firstly smelted into a master alloy ingot in a vacuum induction furnace, and then processed into alloy rods, and then a plasma rotating electrode atomization method is used to prepare a crack-resistant Fe-Cr-Ni based precipitation-strengthened high-temperature alloy powder.

[0014] Furthermore, the process of obtaining the spare high-temperature alloy powder in step 1 is as follows: the prepared crack-resistant Fe-Cr-Ni based precipitation-strengthened high-temperature alloy powder is sieved and dried to obtain the spare high-temperature alloy powder with a particle size of 15~53μm.

[0015] Furthermore, when the plasma rotating electrode atomization method is used to prepare the crack-resistant Fe-Cr-Ni based precipitation-strengthened high-temperature alloy powder, the relevant parameters are as follows: vacuum degree ≤ 2.5×10 -2 Pa, pressure rise rate <2.5Pa / min, rotation speed is 34000±100r / min, and feed speed is 15~40mm / min.

[0016] Furthermore, the step 2 is specifically as follows:

[0017] Step 2.1: Use Materialise Magics software to create a 3D model layer by layer with a layer thickness of 0.03-0.05 mm. Import the determined 3D model parameters into the selective laser melting equipment.

[0018] Step 2.2: Add the spare high-temperature alloy powder to the feed bin, clean the substrate and preheat it to 100-180°C, and introduce argon gas to make the oxygen content ≤200ppm;

[0019] Step 2.3: Scan layer by layer according to the set parameters to complete the selective laser melting process. After forming, cool to room temperature, remove the substrate, and obtain a dense, crack-free intermediate alloy part. The set parameters are as follows: laser power of 200-350 W, scanning speed of 800-1200 mm / s, scanning pitch of 0.11 mm, layer-by-layer printing, and an inter-layer rotation angle of 67°.

[0020] Furthermore, the step 3 is specifically as follows:

[0021] Step 3.1, performing solution heat treatment on the dense master alloy product, the heat treatment schedule is as follows: 1180~1240℃ / 2h / AC;

[0022] Step 3.2: Perform aging heat treatment on the dense master alloy product after solution heat treatment. The heat treatment system is as follows: 650-750°C / 24h / AC.

[0023] In addition, the present invention also provides a crack-resistant Fe-Cr-Ni based precipitation-strengthened high-temperature alloy prepared based on the preparation method described above, and the mechanical properties of the crack-resistant Fe-Cr-Ni based precipitation-strengthened high-temperature alloy are as follows: room temperature yield strength ≥1103MPa, tensile strength ≥1197MPa, elongation ≥9.2%; 650℃ high temperature yield strength ≥842MPa, tensile strength ≥949MPa, elongation ≥10.1%.

[0024] Finally, the present invention also provides the application of the crack-resistant Fe-Cr-Ni based precipitation-strengthened high-temperature alloy prepared based on the preparation method as described above in the forming of high-temperature complex structural parts in aviation and aerospace.

[0025] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0026] 1) The crack-resistant Fe-Cr-Ni-based precipitation-strengthened high-temperature alloy powder provided by the present invention, through a low Si, low C, and high Co composition design, inhibits Si segregation at grain boundaries, significantly reduces the tendency of brittle silicides to form at grain boundaries, and controls the chemical ratio of carbide-forming elements and C to avoid the splitting effect of large-sized blocky carbides (>1μm) on grain boundaries. The high solid solution strengthening coefficient of Co enhances matrix strength, while Co and Cr form a short-range ordered structure, raising the solidus-liquid line temperature and lowering the solidification range to approximately 80°C (conventional alloys are approximately 120°C), effectively inhibiting the initiation of hot cracks.

[0027] 2) The preparation method provided by the present invention can reduce thermal stress accumulation by optimizing laser melting parameters and matching the solidification characteristics of Fe-Cr-Ni-based precipitation-strengthened high-temperature alloys. In addition, during the heat treatment process, the heating rate in the medium and low temperature sections is controlled at 20-30°C / min, which is conducive to quickly passing through the medium-temperature deplasticization temperature range and alleviating the generation of strain aging cracks. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings are incorporated in and constitute a part of this specification and, together with the description, serve to explain the principles of the invention.

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0030] Figure 1 A flow chart of a method for preparing a crack-resistant Fe-Cr-Ni based precipitation-strengthened high-temperature alloy provided by the present invention;

[0031] Figure 2 This is a microstructure diagram of the Fe-Cr-Ni based precipitation strengthened high temperature alloy prepared in Example 1 of the present invention after polishing treatment of the deposited state;

[0032] Figure 3 This is a microstructure diagram of the Fe-Cr-Ni based precipitation-strengthened high-temperature alloy prepared in Example 2 of the present invention after polishing treatment;

[0033] Figure 4 This is the microstructure of the Fe-Cr-Ni based precipitation strengthened high temperature alloy prepared in Example 3 of the present invention after polishing in the deposited state. DETAILED DESCRIPTION

[0034] Here, exemplary embodiments will be described in detail, and the embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Instead, they are only examples consistent with some aspects of the present invention described in detail in the appended claims.

[0035] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. Example 1

[0036] See also Figure 1 As shown, this embodiment provides a method for preparing a crack-resistant Fe-Cr-Ni based precipitation-strengthened high-temperature alloy, comprising the following steps:

[0037] Step 1: pretreating the crack-resistant Fe-Cr-Ni-based precipitation-strengthened high-temperature alloy powder described above in part or in whole to obtain a standby high-temperature alloy powder;

[0038] Step 2: performing selective laser melting on the prepared high-temperature alloy powder to produce a dense master alloy part;

[0039] Step 3: heat-treating the dense intermediate alloy product to obtain a target high-temperature alloy product.

[0040] Furthermore, in step 1, the preparation process of the crack-resistant Fe-Cr-Ni based precipitation-strengthened high-temperature alloy powder is as follows:

[0041] The raw materials of each component are weighed according to the required weight percentage, firstly smelted into a master alloy ingot in a vacuum induction furnace, and then processed into alloy rods, and then a plasma rotating electrode atomization method is used to prepare a crack-resistant Fe-Cr-Ni based precipitation-strengthened high-temperature alloy powder.

[0042] Specifically, step 1 is as follows:

[0043] Step 1.1. Weigh each component raw material according to the required weight percentage. The weight percentage of each component raw material is as follows: Cr: 15.3wt.%, Co: 9.5wt.%, W: 2.6wt.%, C: 0.05wt.%, Al: 3.3wt.%, Ti: 3.2wt.%, Nb: 1.0wt.%, B: 0.01wt.%, Zr: 0.1wt.%, Fe: 1.0 wt.%, Si: 0.05wt.%, the total content of impurity elements is ≤0.01wt.%, and the balance is Ni;

[0044] Step 1.2: using a vacuum induction furnace to melt a master alloy ingot, and processing the master alloy ingot into an alloy rod; wherein the alloy rod has a diameter of Φ60 mm, a length of 700 mm, a surface roughness of less than 2.0 μm, and an end face perpendicularity of less than 0.3 mm;

[0045] Step 1.3: Charge the alloy rods and reduce the vacuum degree of the plasma rotating electrode atomization chamber to ≤2.5×10 -2 Pa, control the pressure rise rate to <2.5Pa / min, set the rotation speed to 34000±100r / min, and the feed speed to 15mm / min, perform centrifugal atomization powder making, and collect the prepared crack-resistant Fe-Cr-Ni based precipitation-strengthened high-temperature alloy powder into a material tank;

[0046] Step 1.4: The crack-resistant Fe-Cr-Ni-based precipitation-strengthened superalloy powder was screened through 15 μm and 53 μm ultrasonic sieves to obtain 15-53 μm Fe-Cr-Ni-based superalloy spherical powder as the spare superalloy powder, i.e., the raw material for the selective laser melting process. Its properties are shown in Table 1 below.

[0047] Table 1 Powder properties of Fe-Cr-Ni based precipitation strengthened superalloy prepared by PREP

[0048]

[0049] Furthermore, the step 2 is specifically as follows:

[0050] Step 2.1: Use Materialise Magics software to create a 3D model layer by layer with a layer thickness of 0.04 mm. Import the determined 3D model parameters into the selective laser melting equipment.

[0051] Step 2.2: Add the alloy powder to the feed bin, clean the substrate, and preheat the substrate to 100°C at a heating rate of 5°C / min. Add argon gas to keep the oxygen content ≤200ppm.

[0052] Step 2.3, scan layer by layer according to the set parameters to complete the selective laser melting forming, cool to room temperature after forming, remove the substrate, and obtain a crack-free dense master alloy part. Figure 2 ; Among them, the setting parameters are as follows: laser power is 285W, scanning speed is 1060mm / s, scanning spacing is 0.11mm, layer-by-layer printing, and inter-layer rotation angle is 67°.

[0053] Furthermore, step 3 is specifically as follows:

[0054] Step 3.1, performing solution heat treatment on the dense master alloy product, the heat treatment schedule is as follows: 1200°C / 2h / AC, i.e., first heating to 900°C at a heating rate of 20°C / min, then heating to 1200°C at a heating rate of 5°C / min, holding at that temperature for 2h, and then air cooling;

[0055] Step 3.2: The dense master alloy product after solution heat treatment was subjected to aging heat treatment. The heat treatment schedule was as follows: 750°C / 24h / AC. That is, when the furnace temperature rose to 750°C, the dense master alloy product after solution heat treatment was placed in the furnace, kept at this temperature for 24h, and then removed from the furnace and air-cooled to obtain the target high-temperature alloy product. The mechanical properties of the product are shown in Table 2 below.

[0056] Table 2 Tensile properties of Fe-Cr-Ni based precipitation strengthened superalloy after heat treatment

[0057] Example 2

[0058] This embodiment provides a method for preparing a crack-resistant Fe-Cr-Ni based precipitation-strengthened high-temperature alloy, comprising the following steps:

[0059] Step 1: pretreating the crack-resistant Fe-Cr-Ni-based precipitation-strengthened high-temperature alloy powder described above in part or in whole to obtain a standby high-temperature alloy powder;

[0060] Step 2: performing selective laser melting on the prepared high-temperature alloy powder to produce a dense master alloy part;

[0061] Step 3: heat-treating the dense intermediate alloy product to obtain a target high-temperature alloy product.

[0062] Furthermore, in step 1, the preparation process of the crack-resistant Fe-Cr-Ni based precipitation-strengthened high-temperature alloy powder is as follows:

[0063] The raw materials of each component are weighed according to the required weight percentage, firstly smelted into a master alloy ingot in a vacuum induction furnace, and then processed into alloy rods, and then a plasma rotating electrode atomization method is used to prepare a crack-resistant Fe-Cr-Ni based precipitation-strengthened high-temperature alloy powder.

[0064] Specifically, step 1 is as follows:

[0065] Step 1.1. Weigh each component raw material according to the required weight percentage. The weight percentage of each component raw material is as follows: Cr: 15.3wt.%, Co: 9.7wt.%, W: 2.6wt.%, C: 0.06wt.%, Al: 3.4wt.%, Ti: 3.2wt.%, Nb: 0.8wt.%, B: 0.01wt.%, Zr: 0.08wt.%, Fe: 1.0wt.%, Si: 0.08wt.%, the total content of impurity elements is ≤0.01wt.%, and the balance is Ni;

[0066] Step 1.2: using a vacuum induction furnace to melt a master alloy ingot, and processing the master alloy ingot into an alloy rod; wherein the alloy rod has a diameter of Φ60 mm, a length of 700 mm, a surface roughness of less than 2.0 μm, and an end face perpendicularity of less than 0.3 mm;

[0067] Step 1.3: Charge the alloy rods and reduce the vacuum degree of the plasma rotating electrode atomization chamber to ≤2.5×10 -2 Pa, control the pressure rise rate to <2.5Pa / min, set the rotation speed to 34000±100r / min, and the feed speed to 15mm / min, perform centrifugal atomization powder making, and collect the prepared crack-resistant Fe-Cr-Ni based precipitation-strengthened high-temperature alloy powder into a material tank;

[0068] Step 1.4: The crack-resistant Fe-Cr-Ni-based precipitation-strengthened superalloy powder was screened through 15 μm and 53 μm ultrasonic sieves to obtain 15-53 μm Fe-Cr-Ni-based superalloy spherical powder as the spare superalloy powder, i.e., the raw material for the selective laser melting process. Its properties are shown in Table 3 below.

[0069] Table 3 Powder properties of Fe-Cr-Ni based precipitation strengthened superalloy prepared by PREP

[0070]

[0071] Furthermore, the step 2 is specifically as follows:

[0072] Step 2.1: Use Materialise Magics software to create a 3D model layer by layer with a layer thickness of 0.04 mm. Import the determined 3D model parameters into the selective laser melting equipment.

[0073] Step 2.2: Add the alloy powder to the feed bin, clean the substrate and preheat it to 120°C at a heating rate of 5°C / min, and introduce argon gas to keep the oxygen content ≤200ppm;

[0074] Step 2.3, scan layer by layer according to the set parameters to complete the selective laser melting forming, cool to room temperature after forming, remove the substrate, and obtain a crack-free dense master alloy part. Figure 3 ; Among them, the setting parameters are as follows: laser power is 285W, scanning speed is 1060mm / s, scanning spacing is 0.11mm, layer-by-layer printing, and inter-layer rotation angle is 67°.

[0075] Furthermore, step 3 is specifically as follows:

[0076] Step 3.1, solution heat treatment is performed on the dense master alloy product. The heat treatment schedule is as follows: 1240°C / 2h / AC, i.e., first heating to 900°C at a heating rate of 25°C / min, then heating to 1240°C at a heating rate of 5°C / min, holding at that temperature for 2h, and then air cooling.

[0077] Step 3.2: The dense master alloy product after the solution heat treatment was subjected to aging heat treatment. The heat treatment schedule was as follows: 650°C / 24h / AC. That is, when the furnace temperature rose to 650°C, the dense master alloy product after the solution heat treatment was placed in the furnace, kept at this temperature for 24h, and then removed from the furnace and air-cooled to obtain the target high-temperature alloy product. The mechanical properties of the product are shown in Table 4 below.

[0078] Table 4 Tensile properties of Fe-Cr-Ni based precipitation strengthened superalloy after heat treatment

[0079] Example 3

[0080] This embodiment provides a method for preparing a crack-resistant Fe-Cr-Ni based precipitation-strengthened high-temperature alloy, comprising the following steps:

[0081] Step 1: pretreating the crack-resistant Fe-Cr-Ni-based precipitation-strengthened high-temperature alloy powder described above in part or in whole to obtain a standby high-temperature alloy powder;

[0082] Step 2: performing selective laser melting on the prepared high-temperature alloy powder to produce a dense master alloy part;

[0083] Step 3: heat-treating the dense intermediate alloy product to obtain a target high-temperature alloy product.

[0084] Furthermore, in step 1, the preparation process of the crack-resistant Fe-Cr-Ni based precipitation-strengthened high-temperature alloy powder is as follows:

[0085] The raw materials of each component are weighed according to the required weight percentage, firstly smelted into a master alloy ingot in a vacuum induction furnace, and then processed into alloy rods, and then a plasma rotating electrode atomization method is used to prepare a crack-resistant Fe-Cr-Ni based precipitation-strengthened high-temperature alloy powder.

[0086] Specifically, step 1 is as follows:

[0087] Step 1.1. Weigh each component raw material according to the required weight percentage. The weight percentage of each component raw material is as follows: Cr: 15.5wt.%, Co: 10wt.%, W: 2.9wt.%, C: 0.08wt.%, Al: 3.7wt.%, Ti: 3.5wt.%, Nb: 0.6wt.%, B: 0.02wt.%, Zr: 0.05wt.%, Fe: 1.5wt.%, Si: 0.1wt.%, the total content of impurity elements is ≤0.01wt.%, and the balance is Ni;

[0088] Step 1.2: using a vacuum induction furnace to melt a master alloy ingot, and processing the master alloy ingot into an alloy rod; wherein the alloy rod has a diameter of Φ60 mm, a length of 700 mm, a surface roughness of less than 2.0 μm, and an end face perpendicularity of less than 0.3 mm;

[0089] Step 1.3: Charge the alloy rods and reduce the vacuum degree of the plasma rotating electrode atomization chamber to ≤2.5×10 -2 Pa, control the pressure rise rate to <2.5Pa / min, set the rotation speed to 34000±100r / min, and the feed speed to 15mm / min, perform centrifugal atomization powder making, and collect the prepared crack-resistant Fe-Cr-Ni based precipitation-strengthened high-temperature alloy powder into a material tank;

[0090] Step 1.4: The crack-resistant Fe-Cr-Ni-based precipitation-strengthened superalloy powder was screened through 15 μm and 53 μm ultrasonic sieves to obtain 15-53 μm Fe-Cr-Ni-based superalloy spherical powder as the spare superalloy powder, i.e., the raw material for the selective laser melting process. Its properties are shown in Table 5 below.

[0091] Table 5 Powder properties of Fe-Cr-Ni based precipitation strengthened superalloy prepared by PREP

[0092]

[0093] Furthermore, the step 2 is specifically as follows:

[0094] Step 2.1: Use Materialise Magics software to create a 3D model layer by layer with a layer thickness of 0.04 mm. Import the determined 3D model parameters into the selective laser melting equipment.

[0095] Step 2.2: Add the alloy powder to the feed bin, clean the substrate and preheat it to 180°C at a heating rate of 5°C / min, and introduce argon gas to keep the oxygen content ≤200ppm;

[0096] Step 2.3, scan layer by layer according to the set parameters to complete the selective laser melting forming, cool to room temperature after forming, remove the substrate, and obtain a crack-free dense master alloy part. Figure 4 ; Among them, the setting parameters are as follows: laser power is 350W, scanning speed is 1200mm / s, scanning spacing is 0.11mm, layer-by-layer printing, and inter-layer rotation angle is 67°.

[0097] Furthermore, step 3 is specifically as follows:

[0098] Step 3.1, performing solution heat treatment on the dense master alloy product, the heat treatment schedule is as follows: 1200°C / 2h / AC, i.e., first heating to 900°C at a heating rate of 30°C / min, then heating to 1200°C at a heating rate of 5°C / min, holding at that temperature for 2h, and then air cooling;

[0099] Step 3.2: The dense master alloy product after solution heat treatment was subjected to aging heat treatment. The heat treatment schedule was as follows: 750°C / 24h / AC. That is, when the furnace temperature rose to 750°C, the dense master alloy product after solution heat treatment was placed in the furnace, kept at this temperature for 24h, and then removed from the furnace and air-cooled to obtain the target high-temperature alloy product. The mechanical properties of the product are shown in Table 6 below.

[0100] Table 6 Tensile properties of Fe-Cr-Ni based precipitation strengthened superalloy after heat treatment

[0101]

[0102] In summary, the present invention achieves crack-free, highly densified Fe-Cr-Ni-based precipitation-strengthened superalloys by selective laser melting (SLM) by regulating the C, Si, and Co elemental contents and combining them with specific composition design. The Fe-Cr-Ni-based precipitation-strengthened superalloys prepared by the present method exhibit excellent mechanical properties, including a room temperature yield strength of ≥1103 MPa, a tensile strength of ≥1197 MPa, and an elongation of ≥9.2%; and a high-temperature yield strength of ≥842 MPa, a tensile strength of ≥949 MPa, and an elongation of ≥10.1% at 650°C.

[0103] The foregoing description is intended only to provide specific embodiments of the present invention, which will enable those skilled in the art to understand and implement the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention.

[0104] It should be understood that the present invention is not limited to the above description and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

Claims

1. A method for preparing a crack-resistant Fe-Cr-Ni based precipitation-strengthened high-temperature alloy, characterized in that: The following steps are involved: Step 1. Pretreating crack-resistant Fe-Cr-Ni based precipitation-strengthened high-temperature alloy powder to obtain a standby high-temperature alloy powder; the crack-resistant Fe-Cr-Ni based precipitation-strengthened high-temperature alloy powder is composed of the following components, by weight percentage: Cr: 15-15.5wt.%, Co: 9.5-10wt.%, W: 2.4-3wt.%, C: 0.05-0.08wt.%, Al: 3.2-3.7wt.%, Ti: 3-3.5wt.%, Nb: 0.6-1.1wt.%, B: 0.01-0.02wt.%, Zr: 0.05-0.15wt.%, Fe: 0.5-1.5wt.%, Si: 0.05-0.1wt.%, total impurity element content ≤0.01wt.%, and the balance is Ni; Step 2: Selectively laser melting the prepared high-temperature alloy powder to produce a dense master alloy part; wherein the selective laser melting is performed by scanning the layers according to set parameters, wherein the set parameters are as follows: laser power of 200-350W, scanning speed of 800-1200mm / s, scanning pitch of 0.11mm, layer-by-layer printing, and an inter-layer rotation angle of 67°; Step 3: heat-treating the dense master alloy product to obtain a target high-temperature alloy product; specifically: Step 3.1: Solution heat treatment is performed on the dense master alloy product at the following temperature regime: 1180-1240°C / 2h / AC. The temperature is first raised to 900°C at a heating rate of 20°C / min to facilitate rapid passage through the intermediate plastic loss temperature range and mitigate strain aging cracking. Step 3.2: Perform aging heat treatment on the dense master alloy product after solution heat treatment. The heat treatment system is as follows: 650-750°C / 24h / AC.

2. The method for preparing the crack-resistant Fe-Cr-Ni based precipitation-strengthened high-temperature alloy according to claim 1, characterized in that: The particle size of the high-temperature alloy powder is 15-53 μm, the average particle size is ≤45 μm, the oxygen content is <100 ppm, and the apparent density is ≥4.47 g / cm 3 , tap density ≥5.28g / cm 3 .

3. The method for preparing the crack-resistant Fe-Cr-Ni based precipitation-strengthened high-temperature alloy according to claim 1, characterized in that: In step 1, the preparation process of the crack-resistant Fe-Cr-Ni based precipitation-strengthened high-temperature alloy powder is as follows: The raw materials of each component are weighed according to the required weight percentage, firstly smelted into a master alloy ingot in a vacuum induction furnace, and then processed into alloy rods, and then a plasma rotating electrode atomization method is used to prepare a crack-resistant Fe-Cr-Ni based precipitation-strengthened high-temperature alloy powder.

4. The method for preparing the crack-resistant Fe-Cr-Ni based precipitation-strengthened high-temperature alloy according to claim 3, characterized in that: The process of obtaining the spare high-temperature alloy powder in step 1 is as follows: the prepared crack-resistant Fe-Cr-Ni based precipitation-strengthened high-temperature alloy powder is sieved and dried to obtain the spare high-temperature alloy powder with a particle size of 15~53μm.

5. The method for preparing the crack-resistant Fe-Cr-Ni based precipitation-strengthened high-temperature alloy according to claim 3, characterized in that: When using the plasma rotating electrode atomization method to prepare crack-resistant Fe-Cr-Ni based precipitation-strengthened high-temperature alloy powder, the relevant parameters are as follows: vacuum degree ≤ 2.5×10 -2 Pa, pressure rise rate <2.5Pa / min, rotation speed is 34000±100r / min, and feed speed is 15~40mm / min.

6. The method for preparing the crack-resistant Fe-Cr-Ni based precipitation-strengthened high-temperature alloy according to claim 1, characterized in that: The step 2 is specifically as follows: Step 2.1: Use Materialise Magics software to create a 3D model layer by layer, with a layer thickness of 0.03-0.05 mm. Import the determined 3D model parameters into the selective laser melting equipment; Step 2.2: Add the spare high-temperature alloy powder to the feed bin, clean the substrate and preheat it to 100-180°C, and introduce argon gas to make the oxygen content ≤200ppm; Step 2.3: Scan the layer by layer according to the set parameters to complete the selective laser melting forming. After forming, cool to room temperature and remove the substrate to obtain a crack-free dense master alloy part.

7. The crack-resistant Fe-Cr-Ni based precipitation-strengthened high-temperature alloy prepared by the preparation method according to any one of claims 1 to 6, characterized in that: The mechanical properties of the crack-resistant Fe-Cr-Ni based precipitation-strengthened high-temperature alloy are as follows: room temperature yield strength ≥1103 MPa, tensile strength ≥1197 MPa, and elongation ≥9.2%; 650°C high-temperature yield strength ≥842 MPa, tensile strength ≥949 MPa, and elongation ≥10.1%.

8. Application of the crack-resistant Fe-Cr-Ni based precipitation-strengthened high-temperature alloy prepared by the preparation method according to any one of claims 1 to 6 in the forming of high-temperature complex structural parts in aviation and aerospace.

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