Anti-crack Fe-Cr-Ni-based precipitation strengthening high-temperature alloy and preparation method and application thereof

Abstract

The invention belongs to the technical field of metal additive manufacturing, and relates to an anti-crack Fe-Cr-Ni-based precipitation strengthening high-temperature alloy and a preparation method and application thereof. By regulating and controlling the contents of C, Si and Co elements and combining specific component design, crack-free and high-compactness of the Fe-Cr-Ni-based precipitation strengthening high-temperature alloy formed through selective laser melting is achieved. The Fe-Cr-Ni-based precipitation strengthening high-temperature alloy prepared through the method is excellent in mechanical property, the room-temperature yield strength is larger than or equal to 1103 MPa, the tensile strength is larger than or equal to 1197 MPa, and the ductility is larger than or equal to 9.2%; the yield strength at the high temperature of 650 DEG C is not less than 842 MPa, the tensile strength is not less than 949 MPa, and the ductility is not less than 10.1%.

Description

Technical Field

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

[0002] Fe-Cr-Ni based precipitation-strengthened superalloys are widely used in high-temperature environments such as turbine working blades of aeroengines below 900°C due to their excellent high-temperature strength, oxidation resistance, and corrosion resistance. However, the existing Fe-Cr-Ni based precipitation-strengthened superalloy compositions are suitable for casting, such as K438 alloy. During the selective laser melting process, due to high cooling rates and thermal stress concentration, microcracks are extremely likely to occur, resulting in low density of the formed parts, seriously affecting the mechanical properties of the parts and the quality and safety of the products. In the prior art, cracking is usually alleviated by adding rare earth elements (such as Ce, Y) or adjusting process parameters. However, excessive rare earths will form brittle phases, which will instead exacerbate the crack tendency, leading to high costs and low efficiency in post-treatment (such as hot isostatic pressing).

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

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

[0005] To achieve the above purpose, the present invention provides the following technical solutions: On the one hand, the present invention provides a crack-resistant Fe-Cr-Ni based precipitation-strengthened superalloy powder, which is composed of the following components by weight percentage: Cr: 15~15.5 wt.%, Co: 9.5~10 wt.%, W: 2.4~3 wt.%, C: 0.05~0.08 wt.%, Al: 3.2~3.7 wt.%, Ti: 3~3.5 wt.%, Nb: 0.6~1.1 wt.%, B: 0.01~0.02 wt.%, Zr: 0.05~0.15 wt.%, Fe: 0.5~1.5 wt.%, Si: 0.05~0.1 wt.%, the total content of impurity elements ≤ 0.01 wt.%, and the balance is Ni.

[0006] Specifically, the particle size of the superalloy powder is 15~53 μm, the average particle size ≤ 45 μm, the oxygen content < 100 ppm, the loose bulk density ≥ 4.47 g / cm 3 , and the tapped density ≥ 5.28 g / cm 3 .

[0007] On the other hand, the present invention also provides a method for preparing a crack-resistant Fe-Cr-Ni-based precipitation-strengthened superalloy, comprising the following steps: Step 1: Pretreat the crack-resistant Fe-Cr-Ni-based precipitation-strengthened superalloy powder described above in part or in whole to obtain standby superalloy powder; Step 2: Selective laser melting and forming of the standby superalloy powder to obtain a dense intermediate alloy part; Step 3: Heat-treat the dense intermediate alloy part to obtain the target superalloy part.

[0008] Further, in Step 1, the preparation process of the crack-resistant Fe-Cr-Ni-based precipitation-strengthened superalloy powder is as follows: Weigh each component raw material according to the required weight percentage, first melt it into a master alloy ingot using a vacuum induction furnace, process the master alloy ingot into an alloy rod, and then use the plasma rotating electrode atomization method to obtain the crack-resistant Fe-Cr-Ni-based precipitation-strengthened superalloy powder.

[0009] Further, the process of obtaining the standby superalloy powder in Step 1 is as follows: Screen and dry the obtained crack-resistant Fe-Cr-Ni-based precipitation-strengthened superalloy powder to obtain standby superalloy powder with a particle size of 15 - 53 μm.

[0010] Further, when using the plasma rotating electrode atomization method to prepare the crack-resistant Fe-Cr-Ni-based precipitation-strengthened superalloy powder, the relevant parameters are as follows: the vacuum degree ≤ 2.5×10 -2 Pa, the pressure rise rate < 2.5 Pa / min, the rotation speed is 34000 ± 100 r / min, and the feeding speed is 15 - 40 mm / min.

[0011] Further, Step 2 is specifically as follows: Step 2.1: Use Materialise Magics software to build a three-dimensional model layer by layer with a layer thickness of 0.03 - 0.05 mm, and import the parameters of the determined three-dimensional model into the selective laser melting equipment; Step 2.2: Add the standby superalloy powder to the feed bin, clean the substrate and preheat it to 100 - 180 °C, and introduce argon to make the oxygen content ≤ 200 ppm; Step 2.3: Scan layer by layer according to the set parameters to complete the selective laser melting and forming. After forming, cool it to room temperature, remove the substrate, and obtain a crack-free dense intermediate alloy part; among them, the set parameters are as follows: the laser power is 200 - 350 W, the scanning speed is 800 - 1200 mm / s, the scanning spacing is 0.11 mm, print layer by layer, and the interlayer rotation angle is 67°.

[0012] Further, step 3 is specifically as follows: Step 3.1: Perform solution heat treatment on the dense intermediate alloy workpiece, and the heat treatment regime is as follows: 1180~1240°C / 2h / AC; Step 3.2: Perform aging heat treatment on the dense intermediate alloy workpiece after solution heat treatment, and the heat treatment regime is as follows: 650~750°C / 24h / AC.

[0013] In addition, the present invention also provides a crack-resistant Fe-Cr-Ni-based precipitation-strengthened superalloy prepared by the above-mentioned preparation method. The mechanical properties of the crack-resistant Fe-Cr-Ni-based precipitation-strengthened superalloy are as follows: room temperature yield strength ≥ 1103 MPa, tensile strength ≥ 1197 MPa, elongation ≥ 9.2%; 650°C high temperature yield strength ≥ 842 MPa, tensile strength ≥ 949 MPa, elongation ≥ 10.1%.

[0014] Finally, the present invention also provides the application of the crack-resistant Fe-Cr-Ni-based precipitation-strengthened superalloy prepared by the above-mentioned preparation method in the forming of high-temperature complex structural parts in aviation and aerospace.

[0015] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects: 1) The crack-resistant Fe-Cr-Ni-based precipitation-strengthened superalloy powder provided by the present invention, through the design of low-Si, low-C, and high-Co components, inhibits the segregation behavior of Si at grain boundaries, significantly reduces the formation tendency of brittle silicides at grain boundaries, controls the chemical ratio of carbide-forming elements to C, and avoids the splitting effect of large-sized massive carbides (>1μm) on grain boundaries; by the high solid solution strengthening coefficient of Co, the matrix strength is enhanced, and at the same time, Co and Cr form a short-range ordered structure, the solid-liquidus temperature is increased, and the solidification range is reduced to about 80°C (about 120°C for traditional alloys), effectively inhibiting the initiation of hot cracks; 2) The preparation method provided by the present invention can reduce the accumulation of thermal stress by optimizing the laser melting parameters and matching the solidification characteristics of the Fe-Cr-Ni-based precipitation-strengthened superalloy; in addition, in the heat treatment process, the heating rate in the medium and low temperature sections is controlled at 20~30°C / min, which is beneficial to quickly pass through the medium temperature plastic loss temperature range and relieve the generation of strain aging cracks. Description of the Drawings

[0016] The drawings here are incorporated into the specification and form a part of this specification, and are used together with the specification to explain the principles of the present invention.

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0018] Figure 1 It is a flowchart of a preparation method of a crack-resistant Fe-Cr-Ni-based precipitation-strengthened superalloy provided by the present invention; Figure 2 It is a micrograph of the as-deposited and polished Fe-Cr-Ni-based precipitation-strengthened superalloy prepared in Example 1 of the present invention; Figure 3 It is a micrograph of the as-deposited and polished Fe-Cr-Ni-based precipitation-strengthened superalloy prepared in Example 2 of the present invention; Figure 4 It is a micrograph of the as-deposited and polished Fe-Cr-Ni-based precipitation-strengthened superalloy prepared in Example 3 of the present invention. Detailed implementation manners

[0019] Here, the exemplary embodiments will be described in detail. The implementation manners described in the following exemplary embodiments do not represent all implementation manners consistent with the present invention. On the contrary, they are only examples consistent with some aspects of the present invention detailed in the appended claims.

[0020] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the drawings and embodiments. Example 1

[0021] See Figure 1 As shown, this embodiment provides a preparation method of a crack-resistant Fe-Cr-Ni-based precipitation-strengthened superalloy, including the following steps: Step 1. Pretreat the crack-resistant Fe-Cr-Ni-based precipitation-strengthened superalloy powder as described above in part or in whole to obtain standby superalloy powder; Step 2. Selective laser melting and forming of the standby superalloy powder to obtain a dense intermediate alloy part; Step 3. Heat-treat the dense intermediate alloy part to obtain the target superalloy part.

[0022] Further, in Step 1, the preparation process of the crack-resistant Fe-Cr-Ni-based precipitation-strengthened superalloy powder is as follows: Weigh each component raw material according to the required weight percentage. First, melt it into a master alloy ingot using a vacuum induction furnace, and then process the master alloy ingot into an alloy rod. Next, use the plasma rotating electrode atomization method to obtain crack-resistant Fe-Cr-Ni-based precipitation-strengthened superalloy powder.

[0023] Specifically, step 1 is as follows: Step 1.1: Weigh each component raw material according to the required weight percentage. The weight percentages of each component raw material are as follows: Cr: 15.3 wt.%, Co: 9.5 wt.%, W: 2.6 wt.%, C: 0.05 wt.%, Al: 3.3 wt.%, Ti: 3.2 wt.%, Nb: 1.0 wt.%, B: 0.01 wt.%, Zr: 0.1 wt.%, Fe: 1.0 wt.%, Si: 0.05 wt.%, the total content of impurity elements ≤ 0.01 wt.%, and the balance is Ni; Step 1.2: Melt it into a master alloy ingot using a vacuum induction furnace, and then process the master alloy ingot into an alloy rod; among them, the diameter of the alloy rod is Φ60 mm, the length is 700 mm, the surface roughness < 2.0 μm, and the end face perpendicularity < 0.3 mm; Step 1.3: Load the alloy rod, and evacuate the plasma rotating electrode atomization chamber to a vacuum degree ≤ 2.5×10 -2 Pa, control the pressure rise rate < 2.5 Pa / min, set the rotation speed to 34000 ± 100 r / min, and the feeding speed to 15 mm / min, and perform centrifugal atomization to make powder. Collect the prepared crack-resistant Fe-Cr-Ni-based precipitation-strengthened superalloy powder into the feed tank; Step 1.4: Screen the crack-resistant Fe-Cr-Ni-based precipitation-strengthened superalloy powder through 15 μm and 53 μm ultrasonic sieves to obtain 15 - 53 μm Fe-Cr-Ni-based superalloy spherical powder as the standby superalloy powder, that is, the raw material for the selective laser melting process, and its performance is shown in Table 1 below.

[0024] Table 1 Powder properties of Fe-Cr-Ni-based precipitation-strengthened superalloy prepared by PREP

[0025] Furthermore, step 2 is as follows: Step 2.1: Use Materialise Magics software to build a three-dimensional model layer by layer with a layer thickness of 0.04 mm, and import the parameters of the determined three-dimensional model into the selective laser melting equipment; 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, and introduce argon to make the oxygen content ≤ 200 ppm; Step 2.3: Conduct layer-by-layer scanning according to the set parameters to complete selective laser melting forming. After forming, cool to room temperature, remove the substrate, and obtain a crack-free dense intermediate alloy part, as shown in Figure 2 ; among them, the set parameters are as follows: the laser power is 285 W, the scanning speed is 1060 mm / s, the scanning spacing is 0.11 mm, layer-by-layer printing is performed, and the interlayer rotation angle is 67°.

[0026] Further, step 3 is specifically as follows: Step 3.1: Perform solution heat treatment on the dense intermediate alloy part. The heat treatment regime is as follows: 1200 °C / 2 h / AC, that is, first heat up to 900 °C at a heating rate of 20 °C / min, then heat up to 1200 °C at a heating rate of 5 °C / min, hold for 2 h and then furnace-cool to air-cool; Step 3.2: Perform aging heat treatment on the dense intermediate alloy part after solution heat treatment. The heat treatment regime is as follows: 750 °C / 24 h / AC, that is, when the furnace temperature rises to 750 °C, put the dense intermediate alloy part after solution heat treatment into the furnace, hold for 24 h and then furnace-cool to air-cool to obtain the target superalloy part, and its mechanical properties are shown in Table 2 below.

[0027] Table 2 Tensile properties of Fe-Cr-Ni-based precipitation-strengthened superalloy after heat treatment Example 2

[0028] This example provides a method for preparing a crack-resistant Fe-Cr-Ni-based precipitation-strengthened superalloy, including the following steps: Step 1: Pretreat the crack-resistant Fe-Cr-Ni-based precipitation-strengthened superalloy powder as described above in part or in whole to obtain standby superalloy powder; Step 2: Perform selective laser melting forming on the standby superalloy powder to obtain a dense intermediate alloy part; Step 3: Perform heat treatment on the dense intermediate alloy part to obtain the target superalloy part.

[0029] Further, in step 1, the preparation process of the crack-resistant Fe-Cr-Ni-based precipitation-strengthened superalloy powder is as follows: Weigh each component raw material according to the required weight percentage. First, melt it into a master alloy ingot using a vacuum induction furnace, and process the master alloy ingot into an alloy rod. Then, use the plasma rotating electrode atomization method to obtain the crack-resistant Fe-Cr-Ni-based precipitation-strengthened superalloy powder.

[0030] Specifically, step 1 is specifically as follows: Step 1.1: Weigh each component raw material according to the required weight percentages. The weight percentages of each component raw material are as follows: Cr: 15.3 wt.%, Co: 9.7 wt.%, W: 2.6 wt.%, C: 0.06 wt.%, Al: 3.4 wt.%, Ti: 3.2 wt.%, Nb: 0.8 wt.%, B: 0.01 wt.%, Zr: 0.08 wt.%, Fe: 1.0 wt.%, Si: 0.08 wt.%, the total content of impurity elements ≤ 0.01 wt.%, and the balance is Ni; Step 1.2: Melt the master alloy ingot using a vacuum induction furnace and process the master alloy ingot into an alloy rod; wherein, the diameter of the alloy rod is Φ60 mm, the length is 700 mm, the surface roughness < 2.0 μm, and the end face perpendicularity < 0.3 mm; Step 1.3: Load the alloy rod and evacuate the plasma rotating electrode atomization chamber to a vacuum degree ≤ 2.5×10 -2 Pa, control the pressure rise rate < 2.5 Pa / min, set the rotation speed to 34000 ± 100 r / min, and the feed rate to 15 mm / min, and perform centrifugal atomization to produce powder. Collect the prepared crack-resistant Fe-Cr-Ni-based precipitation-strengthened superalloy powder into a feed tank; Step 1.4: Screen the crack-resistant Fe-Cr-Ni-based precipitation-strengthened superalloy powder through 15 μm and 53 μm ultrasonic sieves to obtain 15 - 53 μm Fe-Cr-Ni-based superalloy spherical powder as the standby superalloy powder, which is the raw material for the selective laser melting process. Its properties are shown in Table 3 below.

[0031] Table 3 Powder properties of Fe-Cr-Ni-based precipitation-strengthened superalloy prepared by PREP

[0032] Furthermore, the specific steps of Step 2 are as follows: Step 2.1: Use Materialise Magics software to build a three-dimensional model layer by layer with a layer thickness of 0.04 mm, and import the parameters of the determined three-dimensional model into the selective laser melting equipment; Step 2.2: Add the alloy powder to the feed bin, clean the substrate and preheat the substrate to 120 °C at a heating rate of 5 °C / min, and introduce argon to make the oxygen content ≤ 200 ppm; Step 2.3: Scan layer by layer according to the set parameters to complete the selective laser melting forming. After forming, cool it to room temperature, remove the substrate, and obtain a crack-free dense intermediate alloy part, as shown in Figure 3 ; wherein, the set parameters are as follows: the laser power is 285 W, the scanning speed is 1060 mm / s, the scanning spacing is 0.11 mm, print layer by layer, and the interlayer rotation angle is 67°.

[0033] Further, step 3 is specifically as follows: Step 3.1: Perform solution heat treatment on the dense intermediate alloy workpiece, and the heat treatment regime is as follows: 1240°C / 2h / AC, that is, first heat up to 900°C at a heating rate of 25°C / min, then heat up to 1240°C at a heating rate of 5°C / min, hold for 2h and then take out of the furnace and air cool; Step 3.2: Perform aging heat treatment on the dense intermediate alloy workpiece after solution heat treatment, and the heat treatment regime is as follows: 650°C / 24h / AC, that is, when the furnace temperature rises to 650°C, put the dense intermediate alloy workpiece after solution heat treatment into the furnace, hold for 24h and then take out of the furnace and air cool to obtain the target superalloy workpiece, and its mechanical properties are shown in Table 4 below.

[0034] Table 4 Tensile properties of Fe-Cr-Ni-based precipitation-strengthened superalloy after heat treatment Example 3

[0035] This example provides a preparation method of a crack-resistant Fe-Cr-Ni-based precipitation-strengthened superalloy, including the following steps: Step 1: Pretreat the crack-resistant Fe-Cr-Ni-based precipitation-strengthened superalloy powder as described above in part or in whole to obtain standby superalloy powder; Step 2: Selective laser melting and forming of the standby superalloy powder to obtain a dense intermediate alloy workpiece; Step 3: Perform heat treatment on the dense intermediate alloy workpiece to obtain the target superalloy workpiece.

[0036] Further, in step 1, the preparation process of the crack-resistant Fe-Cr-Ni-based precipitation-strengthened superalloy powder is as follows: Weigh each component raw material according to the required weight percentage, first melt it into a master alloy ingot using a vacuum induction furnace, and process the master alloy ingot into an alloy rod, and then use the plasma rotating electrode atomization method to obtain the crack-resistant Fe-Cr-Ni-based precipitation-strengthened superalloy powder.

[0037] Specifically, step 1 is specifically as follows: Step 1.1: Weigh each component raw material according to the required weight percentage, and the weight percentages of each component raw material are 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 ≤ 0.01wt.%, and the balance is Ni; Step 1.2: Melting the master alloy ingot by a vacuum induction furnace and processing the master alloy ingot into an alloy rod; wherein, the diameter of the alloy rod is Φ60 mm, the length is 700 mm, the surface roughness is < 2.0 μm, and the end face perpendicularity is < 0.3 mm; Step 1.3: Loading the alloy rod, and pumping the vacuum degree of the plasma rotating electrode atomization chamber to ≤ 2.5×10 -2 Pa, controlling the pressure rise rate < 2.5 Pa / min, setting the rotation speed to 34000 ± 100 r / min, and the feeding speed to 15 mm / min, and performing centrifugal atomization to produce powder. Collect the prepared crack-resistant Fe-Cr-Ni-based precipitation-strengthened superalloy powder into a feed tank; Step 1.4: Screening the crack-resistant Fe-Cr-Ni-based precipitation-strengthened superalloy powder through 15-μm and 53-μm ultrasonic sieves to obtain 15-53-μm Fe-Cr-Ni-based superalloy spherical powder as the standby superalloy powder, that is, the raw material for the selective laser melting process. Its properties are shown in Table 5 below.

[0038] Table 5 Powder properties of Fe-Cr-Ni-based precipitation-strengthened superalloy prepared by PREP

[0039] Further, the specific content of Step 2 is as follows: Step 2.1: Using Materialise Magics software to establish a three-dimensional model layer by layer with a layer thickness of 0.04 mm, and importing the parameters of the determined three-dimensional model into the selective laser melting equipment; Step 2.2: Adding the alloy powder into the feed bin, cleaning the substrate and preheating the substrate to 180 °C at a heating rate of 5 °C / min, and introducing argon to make the oxygen content ≤ 200 ppm; Step 2.3: Scanning layer by layer according to the set parameters to complete the selective laser melting forming. After forming, cool it to room temperature, remove the substrate, and obtain a crack-free dense intermediate alloy part, as shown in Figure 4 ; wherein, the set parameters are as follows: the laser power is 350 W, the scanning speed is 1200 mm / s, the scanning spacing is 0.11 mm, printing layer by layer, and the interlayer rotation angle is 67°.

[0040] Further, the specific content of Step 3 is as follows: Step 3.1: Performing solution heat treatment on the dense intermediate alloy part. The heat treatment system is as follows: 1200 °C / 2 h / AC, that is, 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 for 2 h, and then taking it out of the furnace and air cooling; Step 3.2: Perform aging heat treatment on the dense intermediate alloy parts after solution heat treatment. The heat treatment system is as follows: 750°C / 24h / AC. That is, when the furnace temperature rises to 750°C, put the dense intermediate alloy parts after solution heat treatment into the furnace. After keeping warm for 24h, take them out of the furnace and air cool to obtain the target superalloy parts. The mechanical properties are shown in Table 6 below.

[0041] Table 6 Tensile properties of Fe-Cr-Ni-based precipitation-strengthened superalloy after heat treatment

[0042] In summary, by regulating the contents of C, Si, and Co elements and combining with specific composition design, the present invention realizes crack-free and high-density selective laser melting forming of Fe-Cr-Ni-based precipitation-strengthened superalloy. The mechanical properties of the Fe-Cr-Ni-based precipitation-strengthened superalloy prepared by the method of the present invention are excellent. The room temperature yield strength ≥ 1103 MPa, the tensile strength ≥ 1197 MPa, and the elongation ≥ 9.2%; the 650°C high temperature yield strength ≥ 842 MPa, the tensile strength ≥ 949 MPa, and the elongation ≥ 10.1%.

[0043] The above are only specific embodiments of the present invention, enabling those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention.

[0044] It should be understood that the present invention is not limited to the above-described content and can be modified and changed without departing from its scope. The scope of the present invention is only limited by the appended claims.

Claims

1. An anti-cracking Fe-Cr-Ni-based precipitation-strengthened superalloy powder, characterized in that, By weight percentage, it consists of the following components: Cr: 15 - 15.5 wt.%, Co: 9.5 - 10 wt.%, W: 2.4 - 3 wt.%, C: 0.05 - 0.08 wt.%, Al: 3.2 - 3.7 wt.%, Ti: 3 - 3.5 wt.%, Nb: 0.6 - 1.1 wt.%, B: 0.01 - 0.02 wt.%, Zr: 0.05 - 0.15 wt.%, Fe: 0.5 - 1.5 wt.%, Si: 0.05 - 0.1 wt.%, the total content of impurity elements ≤ 0.01 wt.%, and the balance is Ni.

2. The anti-cracking Fe-Cr-Ni-based precipitation-strengthened superalloy powder according to claim 1, wherein The particle size of the superalloy powder is 15 - 53 μm, the average particle size ≤ 45 μm, the oxygen content < 100 ppm, the apparent density ≥ 4.47 g / cm 3 , and the tapped density ≥ 5.28 g / cm 3 .

3. A preparation method of a crack-resistant Fe-Cr-Ni-based precipitation-strengthened superalloy, characterized in that, It includes the following steps: Step 1: Pretreat the crack-resistant Fe-Cr-Ni-based precipitation-strengthened superalloy powder described in any one of Claims 1 - 2 to obtain standby superalloy powder; Step 2: Selective laser melting and forming of the standby superalloy powder to obtain a dense intermediate alloy part; Step 3: Heat-treat the dense intermediate alloy part to obtain the target superalloy part.

4. The preparation method of the crack-resistant Fe-Cr-Ni-based precipitation-strengthened superalloy according to claim 3, characterized in that, In Step 1, the preparation process of the crack-resistant Fe-Cr-Ni-based precipitation-strengthened superalloy powder is as follows: Weigh each component raw material according to the required weight percentage, first melt it into a master alloy ingot using a vacuum induction furnace, process the master alloy ingot into an alloy rod, and then obtain the crack-resistant Fe-Cr-Ni-based precipitation-strengthened superalloy powder using the plasma rotating electrode atomization method.

5. The preparation method of the crack-resistant Fe-Cr-Ni-based precipitation-strengthened superalloy according to claim 4, characterized in that, The process of obtaining the standby superalloy powder in Step 1 is as follows: Screen and dry the obtained crack-resistant Fe-Cr-Ni-based precipitation-strengthened superalloy powder to obtain standby superalloy powder with a particle size of 15 - 53 μm.

6. The preparation method of the crack-resistant Fe-Cr-Ni-based precipitation-strengthened superalloy according to claim 4, wherein, When preparing crack-resistant Fe-Cr-Ni-based precipitation-strengthened superalloy powder by the plasma rotating electrode atomization method, the relevant parameters are as follows: the vacuum degree ≤ 2.5×10 -2 Pa, the pressure rise rate < 2.5 Pa / min, the rotation speed is 34000 ± 100 r / min, and the feeding speed is 15 - 40 mm / min.

7. The preparation method of the crack-resistant Fe-Cr-Ni-based precipitation-strengthened superalloy according to claim 3, wherein, The specific content of Step 2 is as follows: Step 2.1: Use Materialise Magics software to build a three-dimensional model layer by layer with a layer thickness of 0.03 - 0.05 mm, and import the parameters of the determined three-dimensional model into the selective laser melting equipment; Step 2.2: Add the standby superalloy powder to the feed bin, clean the substrate and preheat it to 100 - 180 °C, and introduce argon to make the oxygen content ≤ 200 ppm; Step 2.3: Scan layer by layer according to the set parameters to complete the selective laser melting and forming. After forming, cool it to room temperature, remove the substrate, and obtain a crack-free dense intermediate alloy part; among them, the set parameters are as follows: the laser power is 200 - 350 W, the scanning speed is 800 - 1200 mm / s, the scanning spacing is 0.11 mm, print layer by layer, and the interlayer rotation angle is 67°.

8. The preparation method of the crack-resistant Fe-Cr-Ni-based precipitation-strengthened superalloy according to claim 3, characterized in that, The specific content of Step 3 is as follows: Step 3.1: Perform solution heat treatment on the dense intermediate alloy part, and the heat treatment system is as follows: 1180 - 1240 °C / 2 h / AC; Step 3.2: Perform aging heat treatment on the dense intermediate alloy part after solution heat treatment, and the heat treatment system is as follows: 650 - 750 °C / 24 h / AC.

9. The crack-resistant Fe-Cr-Ni-based precipitation-strengthened superalloy prepared by the preparation method according to any one of claims 3 to 8, characterized in that, The mechanical properties of the crack-resistant Fe-Cr-Ni-based precipitation-strengthened superalloy are as follows: the yield strength at room temperature is ≥1103 MPa, the tensile strength is ≥1197 MPa, and the elongation is ≥9.2%; the high-temperature yield strength at 650 °C is ≥842 MPa, the tensile strength is ≥949 MPa, and the elongation is ≥10.1%.

10. Application of the crack-resistant Fe-Cr-Ni-based precipitation-strengthened superalloy prepared by the preparation method according to any one of claims 3 to 8 in the forming of high-temperature complex structural parts in aviation and aerospace.

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