Preparation method and application of powder metallurgy and isothermal forging In738 disc shaft ring piece

Abstract

The invention belongs to the technical field of nickel-based alloy material processing and forming, and particularly relates to a preparation method and application of a powder metallurgy and isothermal forging In738 disc shaft ring piece. The hot isostatic pressing technology is adopted for preforming the blank, internal gaps and cracks of the material are eliminated, the structure is homogenized, element segregation is improved, the fatigue life is prolonged, and a plastic blank is provided for subsequent isothermal forging. Furthermore, the temperature difference between the blank and the mold is reduced through preheating treatment, deformation resistance sudden change caused by local chilling is avoided, and microcrack initiation is inhibited. In addition, dynamic recrystallization is promoted through isothermal forging, a fine equiaxed crystal structure is obtained, and the high-temperature strength is improved; and through solution treatment, grain coarsening is inhibited, a supersaturated solid solution is reserved, and driving force is provided for aging precipitation. And then a dual-mode gamma'phase strengthening system is formed through a two-stage aging process, and the endurance life is optimized. Therefore, the high-temperature comprehensive mechanical property of the In738 nickel-based alloy is improved, and the use requirement of the In738 nickel-based alloy at high temperature is met.

Description

Technical Field

[0001] The invention belongs to the technical field of nickel-based alloy material processing and forming, and particularly relates to a preparation method and application of an In738 disc shaft ring part by powder metallurgy and isothermal forging. Background Art

[0002] Aircraft engine disc and shaft ring components typically experience long-term service in high-temperature, high-stress, and corrosive environments ranging from 650°C to 900°C. Therefore, materials must possess high precision, high strength and toughness, as well as resistance to creep, oxidation, and hot corrosion. In738 nickel-based superalloy, due to its excellent high-temperature strength, oxidation resistance, and creep resistance, has become a core material in this field.

[0003] However, In738 alloy has a high resistance to deformation, and conventional forging can easily cause cracks and uneven deformation. Machining allowances can reach as high as 50%-70%, making it difficult to meet the near-net-shape requirements for disk-shaft rings. Traditional investment casting is prone to defects such as shrinkage cavities, porosity, and coarse grains, resulting in insufficient fatigue life for disk-shaft rings. Emerging laser powder bed fusion technology can achieve near-net-shape shapes for complex structures, reducing machining requirements. However, after remelting and solidification, the material exhibits strength variations of up to 15%-20% along the build direction, failing to meet the homogenization requirements for disk-shaft rings used in aircraft engines.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a preparation method and application of In738 disc shaft ring parts by powder metallurgy and isothermal forging.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] In one aspect, the present invention provides a method for preparing an In738 disk-shaft ring by powder metallurgy and isothermal forging, comprising the following steps:

[0008] Step 1: Prepare In738 high-temperature alloy powder with a particle size of 53 μm-250 μm; prepare the In738 high-temperature alloy powder with an O content of less than 100 ppm and a N content of less than 100 ppm; the In738 high-temperature alloy powder is a nickel-based high-temperature alloy powder;

[0009] Step 2: A near-net-shape canister is obtained by designing a three-dimensional model of the disk shaft ring, and a 15%-30% shrinkage margin is reserved. The canister is made of 20 steel or 45 steel and has a thickness of 2mm-10mm. The In738 high-temperature alloy powder is loaded into the canister. After the powder is fully loaded, it is subjected to vibration compaction, degassing, and sealing welding in sequence, and then hot isostatic pressing is performed. After cooling, the canister is removed to obtain a blank.

[0010] The parameters of the vibration compaction are: vibration frequency of 30Hz-50Hz, amplitude of 1mm-5mm; the parameters of the degassing are: heating temperature of 400℃-600℃, holding time of 4h-16h, vacuum degree ≤5×10 -3 Pa; the parameters of the hot isostatic pressing are: temperature of 1150°C-1250°C, pressure of 100MPa-200MPa, and holding time of 2h-4h;

[0011] Step 3: preheating the blank and the nickel-based high-temperature alloy mold; the parameters of the preheating treatment are as follows: heating temperature of 1050° C. to 1150° C., holding time of 1 hour to 2 hours; wherein, the protective atmosphere during the preheating treatment is argon gas, and the temperature difference between the blank and the nickel-based high-temperature alloy mold is ≤50° C. to prevent microcracks caused by surface chilling;

[0012] Step 4: Use nickel-based high-temperature alloy mold to isothermally forge the preheated blank to obtain a forged blank; the isothermal forging is divided into three passes, with a single deformation of 15%-30% and a strain rate of 0.01s -1 -0.05s -1 , the temperature during forging is 1050℃-1150℃, and the protective atmosphere is argon;

[0013] Step 5. After the forging blank is subjected to solution treatment and two-stage aging treatment in sequence, it is subjected to shot peening strengthening treatment, with a shot peening pressure of 0.3 MPa-0.5 MPa and a coverage rate of ≥200%, to finally obtain the required In738 disc shaft ring part; the protective atmosphere during the solution treatment and two-stage aging treatment is argon; the solution treatment is: keeping at a temperature of 1150°C-1230°C for 1h-2h and then air cooling to inhibit grain coarsening and retain the supersaturated solid solution; the two-stage aging treatment is: primary aging treatment and secondary aging treatment, the primary aging treatment is: keeping at a temperature of 850°C-920°C for 8h-12h and then air cooling to precipitate a uniformly distributed main γ' phase; the secondary aging treatment is: keeping at a temperature of 750°C-800°C for 24h-48h, furnace cooling to 500°C and then air cooling to precipitate a fine γ' phase and improve the lasting strength.

[0014] On the other hand, the present invention provides an application of an In738 disc-shaft ring part prepared by a method for preparing an In738 disc-shaft ring part by powder metallurgy and isothermal forging, and the application of the In738 disc-shaft ring part in an aeroengine. The In738 disc-shaft ring part has a high-temperature tensile strength of 900 MPa-1250 MPa at 760°C, a lifespan of 150 h-300 h at 760°C and 550 MPa, and a fatigue life of 1.0 × 10 6 -2.0×106 .

[0015] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0016] This invention uses high-purity, specifically particle-size-distributed In738 superalloy powder as raw material. After encapsulating the raw material, it undergoes hot isostatic pressing (HIP). Simultaneously, process parameters are controlled to eliminate internal voids and cracks in the material, improve billet density, homogenize the microstructure, mitigate element segregation, and enhance fatigue life, providing a plastic billet for subsequent isothermal forging. The HIP preforms the billet, reducing subsequent processing and increasing material utilization by over 40% compared to traditional casting or forging, enabling near-net-shape In738 disc-shaft rings. Furthermore, preheating reduces the temperature difference between the billet and the die, avoiding sudden changes in deformation resistance caused by localized chilling and suppressing microcrack initiation. Furthermore, isothermal forging promotes dynamic recrystallization, resulting in a fine equiaxed structure and enhanced high-temperature strength. Solution treatment suppresses grain coarsening and retains a supersaturated solid solution, providing the driving force for aging precipitation. A two-stage aging process then forms a bimodal γ' phase reinforcement system, optimizing endurance life. This improves the high-temperature comprehensive mechanical properties of In738 nickel-based alloy, meets its use requirements under high temperatures, and overcomes the shortcomings of traditional technology such as complex forming process, easy cracking of parts, uneven structure, and low raw material utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] 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.

[0018] 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.

[0019] Figure 1 Flow chart of the preparation method of the present invention. DETAILED DESCRIPTION

[0020] Exemplary embodiments will now be described in detail, with examples shown in the accompanying drawings. The embodiments described in the following exemplary embodiments are not intended to represent all embodiments consistent with the present invention. Instead, they are merely examples consistent with some aspects of the present invention as detailed in the appended claims.

[0021] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the present invention is described in further detail below with reference to the accompanying drawings and embodiments.

[0022] See also Figure 1 The present invention provides a method for preparing an In738 disk-shaft ring by powder metallurgy and isothermal forging, comprising the following steps:

[0023] Step 1: preparing an In738 high-temperature alloy powder having a particle size of 53 μm to 250 μm; obtaining an In738 high-temperature alloy powder having an O content of less than 100 ppm and a N content of less than 100 ppm;

[0024] Step 2: A near-net-shape canister is obtained by designing a three-dimensional model of the disk shaft ring, and a 15%-30% shrinkage margin is reserved. The canister is made of 20 steel or 45 steel and has a thickness of 2mm-10mm. The In738 high-temperature alloy powder is loaded into the canister. After the powder is fully loaded, it is subjected to vibration compaction, degassing, and sealing welding in sequence, and then hot isostatic pressing is performed. After cooling, the canister is removed to obtain a blank.

[0025] The parameters of the vibration compaction are: vibration frequency of 30Hz-50Hz, amplitude of 1mm-5mm; the parameters of the degassing are: heating temperature of 400℃-600℃, holding time of 4h-16h, vacuum degree ≤5×10 -3 Pa; the parameters of the hot isostatic pressing are: temperature of 1150°C-1250°C, pressure of 100MPa-200MPa, and holding time of 2h-4h;

[0026] Step 3: preheating the blank and the nickel-based high-temperature alloy mold; the parameters of the preheating treatment are as follows: heating temperature of 1050° C. to 1150° C., holding time of 1 hour to 2 hours; wherein, the protective atmosphere during the preheating treatment is argon gas, and the temperature difference between the blank and the nickel-based high-temperature alloy mold is ≤50° C. to prevent microcracks caused by surface chilling;

[0027] Step 4: Use nickel-based high-temperature alloy mold to isothermally forge the preheated blank to obtain a forged blank; the isothermal forging is divided into three passes, with a single deformation of 15%-30% and a strain rate of 0.01s -1 -0.05s -1 , the temperature during forging is 1050℃-1150℃, and the protective atmosphere is argon;

[0028] Step 5. After the forging blank is subjected to solution treatment and two-stage aging treatment in sequence, it is subjected to shot peening strengthening treatment, with a shot peening pressure of 0.3MPa-0.5MPa and a coverage rate of ≥200%, to finally obtain the required In738 disk shaft ring part; the protective atmosphere during the solution treatment and two-stage aging treatment is argon; the solution treatment is: keeping at a temperature of 1150℃-1230℃ for 1h-2h and then air cooling to inhibit grain coarsening and retain the supersaturated solid solution; the two-stage aging treatment is: primary aging treatment and secondary aging treatment, the primary aging treatment is: keeping at a temperature of 850℃-920℃ for 8h-12h and then air cooling to precipitate a uniformly distributed main γ' phase; the secondary aging treatment is: keeping at a temperature of 750℃-800℃ for 24h-48h, furnace cooling to 500℃ and then air cooling to precipitate a fine γ' phase to improve high-temperature creep resistance and endurance strength.

[0029] In order to prove the effect of the present invention, the following examples are provided for verification.

[0030] Example 1

[0031] This embodiment provides a method for preparing an In738 disk by powder metallurgy and isothermal forging, which specifically includes the following steps:

[0032] Step 1: preparing an In738 high-temperature alloy powder having a particle size of 53 μm to 150 μm; obtaining an In738 high-temperature alloy powder having an O content of less than 100 ppm and a N content of less than 100 ppm;

[0033] Step 2: A near-net-shape canister is designed based on the three-dimensional model of the disk, with a 25% shrinkage margin reserved. The canister is made of 20 steel with a thickness of 6 mm. The In738 high-temperature alloy powder is loaded into the canister. After the powder is filled, the canister is vibrated at a frequency of 30 Hz and an amplitude of 1 mm. The canister is then heated to 400°C and kept warm for 16 hours, and a vacuum degree of ≤5×10 -3 Pa for degassing, then sealing and welding treatment, and then hot isostatic pressing at a temperature of 1240 ° C and a pressure of 120 MPa for 2 hours, and then machining to remove the jacket after cooling in the furnace to obtain the blank;

[0034] Step 3: Preheat the blank and the nickel-based high-temperature alloy mold at 1100° C. for 1 hour in an argon atmosphere; wherein the temperature difference between the nickel-based high-temperature alloy mold and the blank is ≤50° C. to prevent microcracks caused by surface chilling;

[0035] Step 4: Use nickel-based high-temperature alloy mold to isothermally forge the preheated billet. The forging is divided into three passes. The deformation of the first pass is 30% and the strain rate is 0.05s. -1 The second pass deformation is 25% and the strain rate is 0.03s-1 , to refine the grains; the third pass deformation is 15%, and the strain rate is 0.01s -1 , and perform shaping treatment to ensure dimensional accuracy to obtain a forging blank; wherein, the temperature during isothermal forging is 1100°C and the protective atmosphere is argon;

[0036] Step 5. First, the forging blank is solution treated at a temperature of 1160°C, kept warm for 2 hours, and then air-cooled to inhibit grain coarsening and retain the supersaturated solid solution; then a primary aging treatment is performed at a temperature of 900°C, kept warm for 8 hours, and then air-cooled to precipitate a uniformly distributed main γ' phase; then a secondary aging treatment is performed at a temperature of 750°C, kept warm for 46 hours, furnace cooled to 500°C, and then air-cooled to precipitate a fine γ' phase and improve the long-term strength; finally, shot peening strengthening treatment is performed under the conditions of a shot peening pressure of 0.5 MPa and a coverage rate of ≥200%, and finally the required In738 disk A is obtained.

[0037] Example 2

[0038] This embodiment provides a method for preparing an In738 shaft by powder metallurgy and isothermal forging, which specifically includes the following steps:

[0039] Step 1: preparing an In738 high-temperature alloy powder having a particle size of 53 μm to 250 μm; obtaining an In738 high-temperature alloy powder having an O content of less than 100 ppm and a N content of less than 100 ppm;

[0040] Step 2: A near-net-shape sleeve is designed based on the three-dimensional model of the shaft, with a 30% shrinkage margin reserved. The sleeve is made of 45 steel with a thickness of 8 mm. The In738 high-temperature alloy powder is loaded into the sleeve. After the powder is filled, it is vibrated at a frequency of 50 Hz and an amplitude of 5 mm. The sleeve is then heated to 450°C and kept warm for 10 hours, and a vacuum degree of ≤5×10 -3 Pa for degassing, then sealing and welding treatment, and then hot isostatic pressing at a temperature of 1180 ° C and a pressure of 160 MPa for 3 hours, and then machining to remove the jacket after cooling with the furnace to obtain the blank;

[0041] Step 3: Preheat the blank and the nickel-based high-temperature alloy mold at 1130° C. for 2 hours in an argon atmosphere; wherein the temperature difference between the nickel-based high-temperature alloy mold and the blank is ≤50° C. to prevent microcracks caused by surface chilling;

[0042] Step 4: Use nickel-based high-temperature alloy mold to isothermally forge the preheated billet. The forging is divided into three passes. The deformation of the first pass is 30% and the strain rate is 0.05s. -1 The second pass deformation is 25% and the strain rate is 0.03s -1, to refine the grains; the third pass deformation is 15%, and the strain rate is 0.01s -1 , and perform shaping treatment to ensure dimensional accuracy to obtain a forging blank; wherein the temperature during isothermal forging is 1130°C and the protective atmosphere is argon;

[0043] Step 5. First, the forging blank is solution treated at a temperature of 1220°C, kept warm for 1 hour, and then air-cooled to inhibit grain coarsening and retain the supersaturated solid solution; then a primary aging treatment is performed at a temperature of 880°C, kept warm for 10 hours, and then air-cooled to precipitate a uniformly distributed main γ' phase; then a secondary aging treatment is performed at a temperature of 780°C, kept warm for 26 hours, furnace cooled to 500°C, and then air-cooled to precipitate a fine γ' phase and improve the long-term strength; finally, shot peening strengthening treatment is performed under the conditions of a shot peening pressure of 0.3 MPa and a coverage rate of ≥200%, and finally the required In738 shaft B is obtained.

[0044] Example 3

[0045] This embodiment provides a method for preparing an In738 ring by powder metallurgy and isothermal forging, which specifically includes the following steps:

[0046] Step 1: preparing an In738 high-temperature alloy powder having a particle size of 53 μm to 106 μm; obtaining an In738 high-temperature alloy powder having an O content of less than 100 ppm and a N content of less than 100 ppm;

[0047] Step 2: A near-net-shape canister is designed based on the three-dimensional model of the ring, with a 15% shrinkage margin reserved. The canister is made of 20 steel with a thickness of 10 mm. The In738 high-temperature alloy powder is loaded into the canister. After the powder is filled, the canister is vibrated at a frequency of 40 Hz and an amplitude of 3 mm. The canister is then heated to 480°C and kept warm for 4 hours, and the vacuum degree is ≤5×10 -3 Pa for degassing, then sealing and welding treatment, and then hot isostatic pressing at a temperature of 1160 ° C and a pressure of 180 MPa for 4 hours, and then machining to remove the jacket after cooling with the furnace to obtain the blank;

[0048] Step 3: Preheat the blank and the nickel-based high-temperature alloy mold at 1060° C. for 2 hours in an argon atmosphere; wherein the temperature difference between the nickel-based high-temperature alloy mold and the blank is ≤50° C. to prevent microcracks caused by surface chilling;

[0049] Step 4: Use nickel-based high-temperature alloy mold to isothermally forge the preheated billet. The forging is divided into three passes. The deformation of the first pass is 30% and the strain rate is 0.05s. -1 The second pass deformation is 25% and the strain rate is 0.03s -1, to refine the grains; the third pass deformation is 15%, and the strain rate is 0.01s -1 , and perform shaping treatment to ensure dimensional accuracy to obtain a forging blank; wherein the temperature during isothermal forging is 1060°C and the protective atmosphere is argon;

[0050] Step 5: First, the forging blank is solution treated at a temperature of 1200°C, kept warm for 1 hour, and then air-cooled to inhibit grain coarsening and retain the supersaturated solid solution; then a primary aging treatment is performed at a temperature of 850°C, kept warm for 12 hours, and then air-cooled to precipitate a uniformly distributed main γ' phase; then a secondary aging treatment is performed at a temperature of 800°C, kept warm for 24 hours, furnace cooled to 500°C, and then air-cooled to precipitate a fine γ' phase and improve the long-term strength; finally, shot peening strengthening treatment is performed under the conditions of a shot peening pressure of 0.4MPa and a coverage rate of ≥200%, and finally the required In738 ring C is obtained.

[0051] To further verify the effectiveness of the technical solution provided by the present invention, the following tests were conducted on the above-mentioned In738 disc A, In738 shaft B, and In738 ring C:

[0052] (1) High temperature tensile strength test at 760℃;

[0053] (2) Endurance life test at 760°C and 550 MPa;

[0054] (3) Fatigue life test at 760°C, 500 MPa, R = -1;

[0055] The test results are shown in Table 1:

[0056] Table 1

[0057]

[0058] In summary, it can be seen from the results in Table 1 that the In738 disc, In738 shaft and In738 ring prepared by the preparation method of the present invention have a high temperature tensile strength of 900 MPa-1250 MPa at 760°C, a lifespan of 150 h-300 h at 760°C and 550 MPa, and a fatigue life of 1.0 × 10 6 -2.0×10 6 It is shown that the performance of the In738 disc, In738 shaft and In738 ring prepared by the preparation method of the present invention meets the design requirements and can be used in aircraft engines.

[0059] The present invention adopts hot isostatic pressing technology to preform the blank, eliminate the voids and cracks inside the material, homogenize the structure, improve element segregation, increase fatigue life, and provide a plastic blank for subsequent isothermal forging. Furthermore, the temperature difference between the blank and the mold is reduced by preheating treatment, the sudden change in deformation resistance caused by local quenching is avoided, and the initiation of microcracks is suppressed. In addition, by promoting dynamic recrystallization through isothermal forging, a fine equiaxed crystal structure is obtained, and the high-temperature strength is improved; solution treatment is performed to suppress grain coarsening and retain the supersaturated solid solution, providing a driving force for aging precipitation. A dual-modal γ' phase strengthening system is then formed through a two-stage aging process to optimize the endurance life. Thereby, the high-temperature comprehensive mechanical properties of the In738 nickel-based alloy are improved to meet its use requirements at high temperatures, overcoming the shortcomings of the traditional technology, such as the complex forming process, easy cracking of the parts, uneven structure, and low raw material utilization.

[0060] 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.

[0061] 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 disk-shaft ring part by powder metallurgy and isothermal forging In738, characterized in that: The steps include: Step 1: preparing In738 high-temperature alloy powder of a specific particle size; Step 2: first, the In738 high-temperature alloy powder is placed in a can, and then subjected to vibration compaction, degassing, and sealing welding treatments in sequence, and then hot isostatic pressing is performed. After cooling, the can is removed to obtain a blank; Step 3: preheating the blank and the nickel-based high-temperature alloy mold; Step 4: isothermally forging the preheated blank using a nickel-based high-temperature alloy die to obtain a forging blank; Step 5: The forging blank is subjected to solution treatment and two-stage aging treatment in sequence, and then to strengthening treatment to obtain the required In738 disc shaft ring part.

2. The preparation method according to claim 1, characterized in that In step 1, an In738 high-temperature alloy powder is prepared in which the O content is less than 100 ppm and the N content is less than 100 ppm; the particle size of the In738 high-temperature alloy powder is 53 μm-250 μm.

3. The preparation method according to claim 1, characterized in that In step 2, a near-net-shape package is obtained through three-dimensional model design, and a 15%-30% shrinkage margin is reserved. The package is made of 20 steel or 45 steel and has a thickness of 2mm-10mm.

4. The preparation method according to claim 1, characterized in that In step 2, the parameters of the vibration are: vibration frequency of 30Hz-50Hz, amplitude of 1mm-5mm; the parameters of the degassing are: heating temperature of 400℃-600℃, holding time of 4h-16h, vacuum degree ≤5×10 -3 Pa.

5. The preparation method according to claim 1, characterized in that In step 2, the parameters of the hot isostatic pressing are: temperature of 1150° C.-1250° C., pressure of 100 MPa-200 MPa, and time of 2 h-4 h.

6. The preparation method according to claim 1, characterized in that In step 3, the parameters of the preheat treatment are: heating temperature is 1050°C-1150°C, and holding time is 1h-2h; wherein, the protective atmosphere during the preheat treatment is argon, and the temperature difference between the billet and the nickel-based high-temperature alloy mold is ≤50°C.

7. The preparation method according to claim 1, characterized in that In step 4, the isothermal forging is divided into three passes, with a single deformation of 15%-30% and a strain rate of 0.01s -1 -0.05s -1 The forging temperature is 1050℃-1150℃ and the protective atmosphere is argon.

8. The preparation method according to claim 1, characterized in that In step 5, the protective atmosphere during the solution treatment and the two-stage aging treatment is argon; the solution treatment is: solution treatment at a temperature of 1150°C-1230°C for 1h-2h and then air cooling; the two-stage aging treatment is: primary aging treatment and secondary aging treatment, the primary aging treatment is: keeping at a temperature of 850°C-920°C for 8h-12h and then air cooling; the secondary aging treatment is: keeping at a temperature of 750°C-800°C for 24h-48h, furnace cooling to 500°C and then air cooling.

9. The preparation method according to claim 1, characterized in that In step 5, shot peening treatment is adopted, and the parameters during strengthening are: shot peening pressure is 0.3MPa-0.5MPa, and coverage is ≥200%.

10. Application of the In738 disc shaft ring prepared by the preparation method according to any one of claims 1 to 9, characterized in that: The application of the In738 disc-shaft ring in an aero-engine is as follows: the In738 disc-shaft ring has a high-temperature tensile strength of 900 MPa-1250 MPa at 760°C, a lifespan of 150 h-300 h at 760°C and 550 MPa, and a fatigue life of 1.0 × 10 6 -2.0×10 6 .

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