Multi-stage heat treatment method for preparing high-content strengthening phase high-temperature alloy based on 3D printing and product thereof

Abstract

The multi-stage heat treatment method for preparing the high-content strengthening phase superalloy based on 3D printing comprises the following steps that selective laser melting equipment is adopted, nickel-based superalloy powder serves as a raw material, layer-by-layer scanning melting forming is conducted according to a preset three-dimensional model, and a superalloy test block or component is obtained; and performing multi-stage heat treatment on the high-temperature alloy test block or component. According to the method, selective laser melting equipment is adopted for manufacturing a high-temperature alloy test block or component, then the high-temperature alloy test block or component is sequentially subjected to high-temperature homogenization treatment, high-temperature solution treatment, first-stage aging treatment and second-stage aging treatment, the gamma / gamma phase with high content and optimized morphology can be obtained, the performance potential of the 3D printing high-temperature alloy is fully played, and the production cost is reduced. The volume fraction of the gamma strengthening phase in the obtained high-temperature alloy is larger than or equal to 60%, the average size is 100-500 nm, the gamma strengthening phase is evenly distributed in a gamma matrix in a cubic or spherical mode, and the high-temperature alloy shows excellent mechanical performance in the temperature interval of 750-950 DEG C.

Description

Technical Field

[0001] This invention belongs to the field of alloy technology, specifically relating to a multi-stage heat treatment method for preparing high-temperature alloys with high content of reinforcing phases based on 3D printing and its products. Background Technology

[0002] Nickel-based superalloys are widely used in hot-section components of aircraft engines and gas turbines due to their excellent high-temperature strength, creep resistance, and oxidation resistance. Among them, γ-ray... Ni3(Al,Ti) is the most important and effective strengthening phase in nickel-based superalloys. Its volume fraction, size, morphology and distribution directly determine the high-temperature performance of the alloy.

[0003] Traditional casting or forging processes for manufacturing high-performance superalloys (such as IN738LC and CM247LC) face challenges such as long process flows, difficulty in forming complex components, low material utilization, and high costs. Selective laser melting (SLM), a metal 3D printing technology, offers a novel approach to manufacturing complex high-performance superalloy components, boasting advantages such as high design freedom, short production cycles, and near-net-shape forming. The SLM process features extremely high cooling rates (up to 10⁻⁶ rpm). 6 -10 8 K / s) results in the following inherent defects in the formed high-temperature alloy: 1. Severe elemental segregation: Alloying elements (such as Al, Ti, Ta) do not have enough time to diffuse, resulting in uneven microstructure; 2. High residual stress: Rapid solidification of the molten pool leads to a huge accumulation of thermal stress; 3.γ Insufficient phase formation: Rapid cooling suppressed γ The precipitation of the phase, or the precipitation of coarse, poorly morphological γ-phase during subsequent standard heat treatment. The precipitation of the phase, often accompanied by the precipitation of harmful topologically close-packed (TCP) phases, severely impairs the high-temperature alloy mechanical properties and long-term stability of the alloy.

[0004] Current technologies for heat treatment of SLM-formed high-temperature alloys largely rely on traditional processes, such as direct solution treatment followed by aging. This method often fails to effectively eliminate microscopic defects in the printed state and is difficult to precisely control gamma rays. The precipitation behavior of the phase cannot achieve the ideal high volume fraction, fine and uniform distribution of γ-rays. Therefore, the high-temperature performance of the prepared components (especially the tensile strength and creep performance at 750-950℃) is still significantly different from that of traditional forgings. Summary of the Invention

[0005] To address the problems in the prior art, the present invention aims to provide a multi-stage heat treatment method and its products for preparing high-temperature alloys with high content of reinforcing phases based on 3D printing.

[0006] To achieve the above objectives and technical effects, the technical solution adopted by this invention is as follows: A multi-stage heat treatment method for preparing high-temperature alloys with high content of reinforcing phases based on 3D printing includes the following steps: Step 1: Using a laser selective melting device, nickel-based high-temperature alloy powder is used as raw material. The powder is then scanned and melted layer by layer according to a preset three-dimensional model to obtain a high-temperature alloy test block or component. Step 2: Perform multi-stage heat treatment on the obtained high-temperature alloy test blocks or components.

[0007] Furthermore, in step one, the nickel-based superalloy powder is γ A precipitation-strengthened nickel-based superalloy with a phase-forming element content higher than 6 wt%, designated as D85.

[0008] Furthermore, in step one, the laser selective melting process parameters are as follows: Laser power 180-300W, scanning speed 600-1200mm / s, powder layer thickness 20-40μm, scanning spacing 70-100μm, and a checkerboard or stripe scanning strategy are used to optimize stress distribution.

[0009] Furthermore, in step two, the step of performing multi-stage heat treatment on the obtained high-temperature alloy test block or component includes: (a) High-temperature homogenization treatment; (b) High-temperature solution treatment; (c) Level 1 time-sensitive processing; (d) Secondary time-sensitive processing.

[0010] Furthermore, in step (a), the high-temperature homogenization process includes: Hold at a temperature of 1160-1190℃ and a pressure of 145-170MPa in a vacuum or protective atmosphere for 2-8 hours, then force-cool to below 200℃.

[0011] Furthermore, in step (b), the high-temperature solution treatment step includes: The test block or component after high-temperature homogenization treatment is heated to 1180-1210℃ and held for 2-6 hours, followed by oil quenching or forced air cooling to room temperature.

[0012] Furthermore, in step (c), the steps for Level 1 timeliness processing include: The sample block or component after high-temperature solution treatment is heated to 740-820℃ and held at that temperature for 14-18 hours, then air-cooled to room temperature to precipitate initial, fine γ-rays. Phase serves as the nucleation point.

[0013] Furthermore, in step (d), the secondary time-sensitive processing steps include: After primary aging treatment, the test block or component is heated to 650-750℃ and held at that temperature for 14-16 hours, then air-cooled to room temperature to allow γ-rays to develop. The phase precipitates in large quantities and uniformly and grows to 100-500 nm, while avoiding the precipitation of harmful phases.

[0014] This invention also discloses a multi-stage heat treatment method for preparing high-content reinforcing phase superalloys based on 3D printing and the high-content γ / γ content obtained from the product preparation. Strengthened phase high-temperature alloy.

[0015] Furthermore, the high content of γ / γ Internal γ-phase of reinforced phase high-temperature alloy The volume fraction of the reinforcing phase is ≥60%, with an average size of 100-500 nm, and it is uniformly distributed in a cubic or spherical shape within the γ matrix. The volume fraction of the harmful TCP phase is less than 0.5%. This high content of γ / γ The reinforced phase high-temperature alloy exhibits excellent mechanical properties in the temperature range of 750-950℃, with a high-temperature tensile strength of ≥750MPa at 900℃ and a creep life of ≥110h under the conditions of 750℃ / 620MPa.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention discloses a method for fabricating high-temperature alloy specimens or components using laser selective melting equipment, followed by sequential high-temperature homogenization treatment, high-temperature solution treatment, first-stage aging treatment, and second-stage aging treatment, which can yield γ / γ alloys with high content and optimized morphology. Phase, fully utilize the performance potential of 3D printed high-temperature alloys, the resulting high-temperature alloy internal γ The volume fraction of the strengthening phase is ≥60%, the average size is 100-500nm, and it is uniformly distributed in cubic or spherical form in the γ matrix. The high-temperature alloy exhibits excellent mechanical properties in the temperature range of 750-950℃. Attached Figure Description

[0017] Figure 1 This is the SEM image of Comparative Example 1; Figure 2 This is a SEM image of Embodiment 1 of the present invention. Detailed Implementation

[0018] The present invention will now be described in detail so that its advantages and features can be more easily understood by those skilled in the art, thereby providing a clearer and more explicit definition of the scope of protection of the present invention.

[0019] The following provides a brief overview of one or more aspects to offer a basic understanding of them. This overview is not an exhaustive summary of all conceived aspects, nor is it intended to identify key or decisive elements of all aspects, nor to define the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form to prepare for the more detailed descriptions that follow.

[0020] like Figure 2 As shown, this invention discloses a multi-stage heat treatment method for preparing high-temperature alloys with high content of reinforcing phases based on 3D printing, which can obtain γ / γ-phase alloys with high content and optimized morphology. This allows for the full realization of the performance potential of 3D printed high-temperature alloys.

[0021] This invention discloses a multi-stage heat treatment method and product for preparing high-temperature alloys with high content of reinforcing phases based on 3D printing, comprising the following steps: Step 1: Using a selective laser melting (SLM) device, nickel-based superalloy powder is used as raw material. The powder is then scanned and melted layer by layer according to a preset three-dimensional model to obtain a superalloy specimen or component. The nickel-based superalloy powder is γ-ray... Precipitation-strengthened nickel-based superalloys with a phase-forming element (Al+Ti+Ta) content higher than 6wt% were used. The nickel-based superalloy powder was a powder with independently controlled composition by Ningbo Zhongke Xianglong Lightweight Technology Co., Ltd., and its grade was D85. The above SLM process parameters were: laser power 180-300W, scanning speed 600-1200mm / s, powder layer thickness 20-40μm, scanning spacing 70-100μm, and a checkerboard or stripe scanning strategy was adopted to optimize stress distribution. Step 2: Perform the following heat treatments on the obtained high-temperature alloy test blocks or components in sequence: (a) High-temperature homogenization treatment: Hold at 1160-1190℃ and 145-170MPa in a vacuum or protective atmosphere for 2-8 hours, then force-cool to below 200℃; the core purpose of this step is to eliminate element segregation, dissolve irregular primary carbides and harmful phases precipitated during the printing process, and ensure that alloying elements are fully and uniformly diffused, thus preparing for subsequent γ-ray homogenization. Uniform precipitation of the phase creates conditions for the formation of components; (b) High-temperature solution treatment: The specimen or component after high-temperature homogenization is heated to 1180-1210℃ and held for 2-6 hours, followed by oil quenching or forced gas cooling to room temperature; this step aims to adjust the grain size and dissolve any non-uniform γ-rays that may precipitate during the homogenization cooling process. Phase, and control the morphology and distribution of carbides to form a more uniform matrix; (c) First-level aging treatment: The specimen or component after high-temperature solution treatment is heated to 740-820℃ and held at that temperature for 14-18 hours, followed by air cooling to room temperature. This aging treatment aims to precipitate the initial, fine gamma rays. Phase as nucleation point; (d) Secondary aging treatment: The test block or component after the primary aging treatment is heated to 650-750℃ and held at that temperature for 14-16 hours, followed by air cooling to room temperature; this step is crucial and aims to achieve γ-ray aging. The phase further precipitates in large quantities and uniformly and grows to the optimal size (100-500 nm), while avoiding the precipitation of harmful phases such as TCP, ultimately obtaining a high volume fraction of enhanced phase.

[0022] The high-content γ / γ content prepared by the above method Strengthening phase high-temperature alloys, their internal γ The reinforcing phase has a volume fraction ≥60%, an average size of 100-500 nm, and is uniformly distributed in a cubic or spherical manner within the γ-matrix. The harmful TCP phase has a volume fraction of less than 0.5%. High content γ / γ Strengthened phase high-temperature alloys satisfy: Tensile strength ≥1300MPa, yield strength ≥1000MPa, elongation after fracture ≥10%; The tensile properties at 800℃ are: tensile strength ≥1000MPa, yield strength ≥850MPa, and elongation after fracture ≥8%; The tensile properties at 900℃ are: tensile strength ≥750MPa, yield strength ≥600MPa, and elongation after fracture ≥5%; The corresponding standard is the strength at a test temperature of 800℃ in GJB 5512.1-2005, and its tensile properties are: tensile strength ≥784MPa, measured yield strength, and elongation after fracture ≥3%; It exhibits excellent mechanical properties in the temperature range of 750-950℃, with a high-temperature tensile strength of ≥750MPa at 900℃ and a creep life of ≥110h under the conditions of 750℃ / 620MPa. It still has high strength at the service limit temperature of 900℃ and excellent creep performance at 750℃ / 620MPa. The performance achieved far exceeds the requirements of the standard.

[0023] Example 1 A multi-stage heat treatment method for preparing high-temperature alloys with high content of reinforcing phases based on 3D printing includes the following steps: Step 1: Using a selective laser melting (SLM) device, nickel-based superalloy powder is used as raw material. The powder is then scanned and melted layer by layer according to a preset three-dimensional model to obtain a superalloy specimen or component. The nickel-based superalloy powder is γ-ray... Precipitation-strengthened nickel-based superalloys with a phase-forming element (Al+Ti+Ta) content higher than 6wt% were used. The nickel-based superalloy powder was a powder with independently controlled composition by Ningbo Zhongke Xianglong Lightweight Technology Co., Ltd., and its grade was D85. The above SLM process parameters were: laser power 180W, scanning speed 600mm / s, powder layer thickness 20μm, scanning spacing 70μm, and a checkerboard or stripe scanning strategy was adopted to optimize stress distribution. Step 2: Perform the following heat treatments on the obtained high-temperature alloy test blocks or components in sequence: (a) High-temperature homogenization treatment: The alloy is held at 1160℃ and 145MPa under vacuum for 2 hours, followed by forced air cooling to below 200℃. The core purpose of this step is to eliminate element segregation, dissolve irregular primary carbides and harmful phases precipitated during the printing process, and ensure that alloying elements are fully diffused and homogenized, thus preparing for subsequent γ-ray homogenization. Uniform precipitation of the phase creates conditions for the formation of components; (b) High-temperature solution treatment: The specimen or component after high-temperature homogenization is heated to 1180°C and held for 2 hours, followed by oil quenching to room temperature; this step aims to adjust the grain size and dissolve any non-uniform γ-rays that may precipitate during the homogenization cooling process. Phase, and control the morphology and distribution of carbides to form a more uniform matrix; (c) First-level aging treatment: The specimen or component after high-temperature solution treatment is heated to 740℃ and held at that temperature for 14 hours, and then air-cooled to room temperature. This aging treatment aims to precipitate the initial, fine gamma rays. Phase as nucleation point; (d) Secondary aging treatment: The test block or component after primary aging treatment is heated to 650℃ and held at that temperature for 14 hours, followed by air cooling to room temperature; this step is critical and aims to allow the γ-rays to effloresce. The phase further precipitates in large quantities and uniformly and grows to the optimal size, while avoiding the precipitation of harmful phases such as TCP, ultimately obtaining a high volume fraction of enhanced phase.

[0024] Comparative Example 1 The difference between this comparative example and Example 1 is that step bd was not performed in this comparative example; otherwise, it is the same as Example 1.

[0025] The SEM image of the alloy obtained in Comparative Example 1 is shown below. Figure 1 As shown, the SEM image of the alloy obtained in Example 1 is as follows. Figure 2 As shown. By Figure 1-2 It can be seen that the alloy obtained in Comparative Example 1 has many defects, while the high-content γ / γ alloy prepared in Example 1... Strengthening phase high-temperature alloys, their internal γ The reinforcing phase had a volume fraction of 62.94%, an average size of 180 nm, and was uniformly distributed cubically within the γ-matrix. The harmful TCP phase had a volume fraction of less than 0.5%, and a high content of γ / γ The reinforced phase high-temperature alloy exhibits excellent mechanical properties in the temperature range of 750-950℃, with a high-temperature tensile strength of ≥750MPa at 900℃ and a creep life of ≥110h under the conditions of 750℃ / 620MPa.

[0026] Any parts or structures not specifically described in this invention can be made using existing technologies or products, and will not be elaborated upon here.

[0027] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A multi-stage heat treatment method for the preparation of high content, high temperature alloy with strengthening phase based on 3D printing, characterized by, The method comprises the following steps: Step one, using laser selective melting equipment, taking nickel-based superalloy powder as raw material, and performing layer-by-layer scanning and melting forming according to a preset three-dimensional model to obtain a superalloy test block or component; Step two, performing multi-stage heat treatment on the obtained superalloy test block or component.

2. A multi-stage heat treatment method for producing high content of strengthening phase in high temperature alloy based on 3D printing according to claim 1, characterized in that, In step one, the nickel-based superalloy powder is γ The precipitation-strengthened nickel-based superalloy with a content of phase-forming elements higher than 6 wt% is D85.

3. A multi-stage heat treatment method for producing high content strengthened superalloy based on 3D printing according to claim 1, characterized in that, In step one, the laser selective melting process parameters are as follows: laser power 180-300 W, scanning speed 600-1200 mm / s, powder layer thickness 20-40 μm, scanning interval 70-100 μm, and chessboard or stripe scanning strategy is adopted to optimize stress distribution.

4. The method of claim 1, wherein the method is characterized by, In step two, the steps of performing multi-stage heat treatment on the obtained superalloy test block or component include: (a) high-temperature homogenization treatment; (b) high-temperature solid solution treatment; (c) first-stage aging treatment; (d) second-stage aging treatment.

5. A multi-stage heat treatment method for the preparation of high content of strengthening phase high temperature alloy based on 3D printing according to claim 4, characterized in that, In step (a), the steps of high-temperature homogenization treatment include: holding at a temperature of 1160-1190 ℃ and a pressure of 145-170 MPa in a vacuum or protective atmosphere for 2-8 h, and then forced air cooling to below 200 ℃.

6. A multi-stage heat treatment method for the preparation of high content of strengthening phase high temperature alloy based on 3D printing according to claim 4, characterized in that, In step (b), the steps of high-temperature solid solution treatment include: heating the test block or component after high-temperature homogenization treatment to 1180-1210 ℃, holding for 2-6 h, and then oil quenching or forced air cooling to room temperature.

7. A multi-stage heat treatment method for producing high content strengthened superalloys based on 3D printing according to claim 4, characterized in that, In step (c), the steps of first-stage aging treatment include: The test block or component after high temperature solution treatment is heated to 740-820°C, and held for 14-18h, and then air cooled to room temperature, and the initial, fine γ phase is precipitated as nucleation sites.

8. A multi-stage heat treatment method for producing high content strengthened superalloy based on 3D printing according to claim 4, characterized in that, In step (d), the steps of second-stage aging treatment include: The test block or member after primary aging treatment is heated to 650-750°C, and kept for 14-16h, and then air cooled to room temperature, so that γ The phase precipitates and grows to 100-500nm in a large amount and uniformly, and meanwhile the precipitation of harmful phase is avoided.

9. A high-content strengthened superalloy prepared by the multi-stage heat treatment method according to any one of claims 1-8.

10. A high content, precipitate strengthened superalloy as in claim 9, wherein, Its internal γ The volume fraction of the strengthening phase is ≥60%, the average size is 100-500nm, and it is uniformly distributed in the γ matrix in cubic or spherical shape, the volume fraction of the harmful TCP phase is lower than 0.5%, and the high content γ / γ The strengthening phase high-temperature alloy exhibits excellent mechanical properties in the temperature range of 750-950℃, the high-temperature tensile strength at 900℃ is ≥750MPa, and the stress-rupture life under the condition of 750℃ / 620MPa is ≥110h.

Images