The invention relates to a crystal having grains and [gamma] apos; dual-scale heterogeneous nickel-based alloy with strengthening phase and preparation method of dual-scale heterogeneous nickel-based alloy
The dual-scale heterogeneous nickel-based alloy is prepared through the solution treatment-cold rolling-annealing process, which solves the problem of difficult balance between strength and plasticity of nickel-based alloys in the existing technology and achieves the combination of high strength and high plasticity.
Patent Information
- Application Number
- CN202410321523.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-20
- Publication Date
- 2025-09-23
AI Technical Summary
Existing technologies make it difficult to significantly improve the strength of nickel-based alloys without sacrificing plasticity, and traditional methods make it difficult to achieve a balance between high strength and high plasticity.
A dual-scale heterogeneous nickel-based alloy with grain and γ' phase reinforcement phase is prepared by solution treatment-cold rolling-annealing process. By controlling the rolling passes and heat treatment process, a composite structure of recrystallization, nanocrystalline and γ' phase is formed.
The yield strength of nickel-based alloys is significantly increased to 1406 MPa, while maintaining a uniform elongation of 15.4%, achieving a balance between high strength and high plasticity.
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Figure CN120683396A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of nanostructured metal materials, and in particular to a dual-scale heterogeneous nickel-based alloy having grains and a γ' phase reinforcement phase and a preparation method thereof. Background Art
[0002] Traditional metal materials with homogeneous structures are often modified by solid solution strengthening, fine grain strengthening and other means, but it is difficult to improve the strength and plasticity of the materials at the same time. The introduction of the concept of heterogeneous structure provides another way to strengthen materials. By regulating the microstructure of the material through heterogeneous structure, the mechanical properties of the material have been able to break through the inverted relationship of "strength-plasticity" of traditional materials. In recent years, a large number of researchers have conducted research on heterogeneous structure regulation of face-centered cubic metals, which is due to the excellent deformation ability of the γ matrix FCC structure of nickel-based medium entropy alloys and the excellent strengthening ability of the Ni3 (AlTi) type γ' precipitation phase with L12 structure. NiCoCr nickel-based alloy meets the above requirements very well. The strength and plasticity of the material are improved by introducing grains of different sizes and precipitates of different sizes. This method is simple and low-cost.
[0003] Literature Du X, Li W, Chang H, et al. Dual heterogeneous structures lead to ultrahigh strength and uniform ductility in a Co-Cr-Ni medium-entropy alloy[J]. Nature Communications, 2020, 11(1): 2390. Du et al. used rolling and two-step annealing to treat NiCoCr alloy, obtaining a heterogeneous structure of coarse grains mixed with ultrafine grains, accompanied by the precipitation of a large amount of γ' precipitates. The alloy has a tensile strength of up to 2.2 GPa and a uniform elongation of 13%. The process results in a coarse grain size of 10-30 μm, an ultrafine grain size of 0.5-2 μm, and a precipitate size of about 100 nm. The grain refinement effect is poor, and the precipitation size of the precipitate phase is insufficient.
[0004] Literature Li W., et al. Unraveling the two-stage precipitation mechanism in a hierarchical-structured fcc / L21 high-entropy alloy: Experiments and analytical modeling. Acta Materialia 262. (2024): In W. Li et al. (CoCrFeNi)87 After solutionizing Al7Ti6, water cooling, and heat treatment at 1023K for 4 hours, the sample achieved a yield strength of 751 MPa and an ultimate tensile strength of 1148 MPa. The resulting elongation at break was 7.0%, representing a 38% increase in yield strength and an approximately 86% increase in tensile strength compared to the solutionized sample. This treatment introduces precipitation strengthening, but it makes it difficult to achieve a heterogeneous structure. While significant plasticity is achieved, the strength gain is limited.
[0005] Zhao YL, Yang T, Tong Y, et al. Heterogeneous precipitation behavior and stacking-fault-mediated deformation in a CoCrNi-based medium-entropy alloy[J]. Acta Materialia, 2017, 138: 72-82. Zhao et al. added a small amount of Al and Ti elements to the NiCoCr medium-entropy alloy to prepare a (CoCrNi) 94 The Al3Ti3 alloy, which incorporates precipitation strengthening with an L12 structure, increased yield strength by 74% from 430 MPa to 750 MPa, and tensile strength by 44% from 900 MPa to 1300 MPa. The elongation at break was also 45%. This process resulted in a precipitation-strengthened heterogeneous structure, which minimized elongation loss, but the yield strength achieved was insufficient for engineering applications.
[0006] Plastic deformation techniques can refine grains and thus increase material strength, but this strength improvement often comes at the expense of plasticity. This drawback can be alleviated through specific heat treatment conditions. Mechanical heat treatment is simple, efficient, and widely applicable, making it one of the main methods for preparing nanometal materials. Summary of the Invention
[0007] The object of the present invention is to provide a dual-scale heterogeneous nickel-based alloy having grains and γ' phase strengthening phase and a preparation method thereof. The present invention adopts a solid solution treatment-cold rolling-annealing process to prepare a dual-scale heterogeneous nickel-based alloy having grains and γ' phase strengthening phase. The nickel-based alloy structure contains two heterogeneous structures with different grain sizes, and contains two different sizes of γ' precipitates in two regions.
[0008] The technical solutions for achieving the purpose of the present invention are: A dual-scale heterogeneous nickel-based alloy with grains and γ' phase reinforcement phase. The microstructure of the nickel-based alloy consists of recrystallization, nanocrystals and γ' phase. The yield strength of the nickel-based alloy reaches up to 1406 MPa.
[0009] Preferably, in the microstructure, the recrystallized size is 1-2 μm, the nanocrystalline size is 70-100 nm, and the γ' phase size is 100-600 nm.
[0010] Preferably, the composition of the nickel-based alloy is measured in atomic percentage (at.%) as follows: Ni: 50.22%, Co: 20.94%, Cr: 15.46%, Al: 5.1%, Ti: 4.96%, Mo: 1.8%, Fe: 1.0%, W: 0.4%, Zr: 0.02%, C: 0.05%, B: 0.05%.
[0011] A method for preparing the above-mentioned nickel-based alloy, comprising the following specific steps: (1) Smelting a nickel-based alloy ingot according to its composition, cutting the alloy ingot into block samples by wire cutting, subjecting the block nickel-based alloy to solid solution treatment, and obtaining a nickel-based alloy with uniform structure by air cooling, and removing the surface oxide layer before rolling; (2) rolling the nickel-based alloy, and continuously rolling the nickel-based alloy in successive passes until the total deformation exceeds 70%; (3) The rolled nickel-based alloy is annealed to obtain a dual-scale heterogeneous nickel-based alloy having grains and γ' phase reinforcement.
[0012] Preferably, in step (1), the solution treatment process is: placing the nickel-based alloy in a heating furnace at 1100°C and keeping it warm for 5 hours.
[0013] Preferably, in step (2), the rolling process adopts a twin-roll mill with a roll diameter of 400 mm and a rolling speed of 0.021 m / s. By adjusting the rolling passes and the pressure of each pass, the rolling deformation is controlled at 70-90%, preferably 75-85%, and the rolling pressure of each pass is 0.2-0.5 mm.
[0014] Preferably, in step (3), the annealing process is: placing the cold-rolled nickel-based alloy into a heating furnace, keeping it at 975°C for 8 hours, and then air-cooling it to room temperature, and then keeping it at 725°C for 8 hours, and then air-cooling it to room temperature.
[0015] Compared with the prior art, the present invention has the following significant advantages: (1) The present invention can prepare a dual-scale heterogeneous nickel-based alloy with grains and γ' phase reinforcement phase, the microstructure of which can be precisely controlled by controlling the number of rolling passes and the amount of pressure per pass as well as the heat treatment process, and the preparation effect is stable.
[0016] (2) Rolling is generally divided into two types according to temperature: hot rolling and cold rolling. Hot rolling consumes a lot of energy and has high production costs. In addition, the surface quality of the processed alloy material is poor. Cold rolling can avoid the above-mentioned defects of hot rolling.
[0017] (3) The preparation method provided by the present invention is simple, has low equipment requirements, and is convenient for large-scale industrial production and application.
[0018] (4) For typical solid solution strengthened nickel-based alloys, the strength is difficult to further improve due to the limited solid solution strengthening effect of solution atoms. The present invention retains the solid solution strengthening effect of the nickel-based alloy itself without changing the chemical composition of the material. At the same time, by refining the grains and strengthening by precipitation of the second phase, the microstructure is changed to increase the strength of the nickel-based alloy to 1406 MPa, and the uniform elongation is 15.4%, achieving a higher strength-to-ductility ratio.
[0019] The present invention is further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 This is an EBSD microstructure image of the heterogeneous structure in the nickel-based alloy with 80% rolling deformation in the embodiment.
[0021] Figure 2 3 is a transmission electron microscope image of the heterogeneous structure in the nickel-based alloy with 80% rolling deformation in the embodiment.
[0022] Figure 3 3 is a transmission electron microscope image of nanocrystals in the nickel-based alloy with 80% rolling deformation in the embodiment.
[0023] Figure 4 3 is a transmission electron microscope image of recrystallization in the nickel-based alloy with 80% rolling deformation in the embodiment.
[0024] Figure 5 The graph is a comparison of the yield strength of the nickel-based alloys of the embodiment, cold-rolled nickel-based alloys after solution treatment, and nickel-based alloys subjected to only solution treatment.
[0025] Figure 6 This is a schematic diagram of the principle of the cold rolling and annealing treatment described in the present invention. DETAILED DESCRIPTION
[0026] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.
[0027] The present invention adopts a solution treatment-cold rolling-annealing process to prepare a high-strength nickel-based alloy with a heterogeneous structure and a γ' phase composite structure. First, the nickel-based alloy is solution treated at 1100°C for 5 hours, and then air-cooled to obtain a nickel-based alloy with a uniform structure. Then, a double-roll mill is used with a roll diameter of 400 mm, a rolling speed of 0.021 m / s, and a rolling pressure of 0.2 to 0.5 mm per pass to roll the nickel-based alloy. Figure 5 As shown in the figure, based on the principle of volume invariance, rolling involves interlocking the nickel-based alloy between counter-rotating rollers. The nickel-based alloy enters the gap between the rollers and, under the rolling force, undergoes plastic deformation, resulting in an increase in length, a decrease in thickness, and a slight increase in width. The deformation of the nickel-based alloy is controlled by controlling the number of rolling passes. Multiple rolling passes are performed until the desired deformation is achieved. Heat treatment is used to optimize the structure. The rolled nickel-based alloy is then placed in a furnace at 975°C for 8 hours, then air-cooled. It is then held at 725°C for 8 hours, then air-cooled.
[0028] Rolling causes intense plastic deformation in nickel-based alloys, resulting in grain refinement and the accumulation of numerous dislocations. Reaching the nanoscale requires deformation exceeding 50%, at which point the microstructure becomes dominated by nanocrystals. After annealing, recrystallization occurs, reducing dislocation density. Recrystallized particles reach a size of 1 to 2 μm, nanocrystals of 70 to 100 nm, and γ' phases of 100 to 600 nm. This structure significantly enhances the strength and serviceability of nickel-based alloys, achieving a yield strength of 1406 MPa. Example 1
[0029] A nickel-based alloy with high yield strength, containing dislocations, recrystallization, and nanocrystals, is obtained through solution treatment, cold rolling, and annealing. The chemical elements in the nickel-based alloy are measured in atomic percentage (at%) as follows: Ni: 50.22%, Co: 20.94%, Cr: 15.46%, Al: 5.1%, Ti: 4.96%, Mo: 1.8%, Fe: 1.0%, W: 0.4%, Zr: 0.02%, C: 0.05%, and B: 0.05%.
[0030] According to the above ratio, the nickel-based alloy ingot obtained by smelting was cut into block materials with a size of 10 mm × 15 mm × 50 mm by electric spark wire cutting. The nickel-based alloy sample to be treated was placed in a high-temperature furnace and kept at 1100°C for 5 h for solution treatment.
[0031] like Figure 6Before rolling, the surface of the nickel-based alloy after solution treatment is polished smooth to remove the surface oxide layer. The rolling speed is 0.021 m / s, and the pressing amount for each rolling pass is 0.2 mm. In order to offset the elastic recovery of the nickel-based alloy during the deformation process, after 25-30 rolling passes, the rolling deformation is guaranteed to be 80%.
[0032] like Figure 6 The cold-rolled nickel-based alloy was placed in a heating furnace, kept at 975°C for 8 h and then air-cooled to room temperature, and then kept at 725°C for 8 h and then air-cooled to room temperature.
[0033] The recrystallized area in the nickel-based alloy obtained in this embodiment is surrounded by residual deformation structure, such as Figure 1 The EBSD microstructure image of the heterogeneous structure in the nickel-based alloy with 80% rolling deformation is shown. At the same time, the nickel-based alloy has a nanocrystalline structure, a large number of dislocations and stacking faults in the nanocrystalline, the average grain size of the nanocrystalline is 89.3 nm, and the average structural size of the recrystallized grain is 1.35 μm. Figure 2 Transmission electron microscope image of recrystallization in nickel-based alloy after 80% rolling deformation and annealing. Figure 3 Transmission electron microscope image of nanocrystals in a nickel-based alloy after 80% rolling deformation and annealing. Figure 4 80% rolling deformation of the nickel-based alloy in the embodiment of the transmission electron microscope image of the recrystallization. Figure 5 Comparing the yield strength of the nickel-based alloy in Example 1, a solution-treated state (subject only to the solution treatment of Example 1 without the cold rolling and annealing of Example 1), and a cold-rolled state (subject only to the solution treatment and cold rolling of Example 1 without the annealing of Example 1), the nickel-based alloy achieved a yield strength of 1406 MPa, 1.8 times that of the untreated nickel-based alloy. The uniform elongation was 15.4%, demonstrating a high strength-to-ductility ratio. Rolling and annealing significantly refined the nickel-based alloy's grains, improved its grain structure, and enhanced its strength.
[0034] Results show that the microstructure of the solution-treated, cold-rolled, and annealed nickel-based alloy proposed in this invention is primarily composed of recrystallized, nanocrystals, and γ' phases. Recrystallized alloys range in size from 1 to 2 μm, nanocrystals from 70 to 100 nm, and γ' phases from 100 to 600 nm. The yield strength of the treated nickel-based alloy reached 1406 MPa, a 75% increase compared to the yield strength of the untreated alloy. The preparation method provided by this invention is simple, requires minimal equipment, and can consistently produce nickel-based alloys with heterogeneous structures and γ' phase composites, facilitating large-scale industrialization.
Claims
1. A dual-scale heterogeneous nickel-based alloy having grains and a γ' phase reinforcement phase, characterized in that: The microstructure of the nickel-based alloy consists of recrystallization, nanocrystals and γ' phases, and the yield strength of the nickel-based alloy reaches up to 1406 MPa.
2. The nickel-based alloy according to claim 1, wherein The recrystallized size is 1-2 μm, the nanocrystallite size is 70-100 nm, and the γ' phase size is 100-600 nm.
3. The nickel-based alloy according to claim 1, wherein The composition of the nickel-based alloy is as follows in atomic percentage: Ni: 50.22%, Co: 20.94%, Cr: 15.46%, Al: 5.1%, Ti: 4.96%, Mo: 1.8%, Fe: 1.0%, W: 0.4%, Zr: 0.02%, C: 0.05%, and B: 0.05%.
4. The nickel-based alloy according to any one of claims 1 to 3, characterized in that Prepared by the following steps: (1) Smelting a nickel-based alloy ingot according to its composition, cutting the alloy ingot into block samples by wire cutting, subjecting the block nickel-based alloy to solid solution treatment, and obtaining a nickel-based alloy with uniform structure by air cooling, and removing the surface oxide layer before rolling; (2) rolling the nickel-based alloy, and continuously rolling the nickel-based alloy in successive passes until the total deformation exceeds 70%; (3) The rolled nickel-based alloy is annealed to obtain a dual-scale heterogeneous nickel-based alloy having grains and γ' phase reinforcement.
5. The nickel-based alloy according to claim 4, wherein In step (1), the solution treatment process is: placing the nickel-based alloy in a heating furnace at 1100°C and keeping it warm for 5 hours.
6. The nickel-based alloy according to claim 4, wherein In step (2), the rolling process adopts a twin-roll mill with a roll diameter of 400 mm and a rolling speed of 0.021 m / s. By adjusting the rolling passes and the pressure of each pass, the rolling deformation is controlled at 70-90%, preferably 75-85%, and the rolling pressure of each pass is 0.2-0.5 mm.
7. The nickel-based alloy according to claim 4, wherein In step (3), the annealing process is as follows: the cold-rolled nickel-based alloy is placed in a heating furnace, kept at 975°C for 8 hours, and then air-cooled to room temperature, and then kept at 725°C for 8 hours, and then air-cooled to room temperature.
8. A method for preparing a dual-scale heterogeneous nickel-based alloy having grains and a γ' phase reinforcement phase, characterized in that: The specific steps are as follows: (1) Smelting a nickel-based alloy ingot according to its composition, cutting the alloy ingot into block samples by wire cutting, subjecting the block nickel-based alloy to solid solution treatment, and obtaining a nickel-based alloy with uniform structure by air cooling, and removing the surface oxide layer before rolling; (2) rolling the nickel-based alloy, and continuously rolling the nickel-based alloy in successive passes until the total deformation exceeds 70%; (3) The rolled nickel-based alloy is annealed to obtain a dual-scale heterogeneous nickel-based alloy having grains and γ' phase reinforcement.
9. The method according to claim 8, wherein The composition of the nickel-based alloy is as follows in atomic percentage: Ni: 50.22%, Co: 20.94%, Cr: 15.46%, Al: 5.1%, Ti: 4.96%, Mo: 1.8%, Fe: 1.0%, W: 0.4%, Zr: 0.02%, C: 0.05%, and B: 0.05%.
10. The method according to claim 8, wherein In step (1), the solution treatment process is as follows: the nickel-based alloy is placed in a heating furnace at 1100°C and kept warm for 5 hours; in step (2), the rolling treatment adopts a double-roll mill with a roll diameter of 400 mm and a rolling speed of 0.021 m / s. By adjusting the rolling passes and the pressure of each pass, the rolling deformation is controlled to be 70-90%, preferably 75-85%, and the pressure of each pass is 0.2-0.5 mm; in step (3), the annealing treatment process is as follows: the cold-rolled nickel-based alloy is placed in a heating furnace, kept warm at 975°C for 8 hours, and then air-cooled to room temperature, and then kept warm at 725°C for 8 hours, and then air-cooled to room temperature.