High-strength and high-elongation multi-component alloy and preparation method thereof

Abstract

The invention discloses a high-strength and high-elongation multi-component alloy and a preparation method thereof, and belongs to the technical field of multi-component alloys. The multi-component alloy disclosed by the invention comprises the following components in percentage by mass: 3.5 to 7.2 percent of Al, 19.9 to 23.3 percent of Co, 12.3 to 16.5 percent of Cr, 22.5 to 26.2 percent of Fe, 9.6 to 14.2 percent of W and the balance of Ni and inevitable impurities. Through a component-process coupling effect, stable nano precipitation of a toughening mu phase can be ensured, meanwhile, decomposition of a reinforcing phase BCC and damage to a nano structure due to overgrowth of the mu phase are avoided, meanwhile, a matrix FCC phase assists toughening of the mu phase, a multi-phase synergistic effect is achieved, and the multi-component alloy has excellent comprehensive mechanical properties and is suitable for industrial production. Therefore, the multi-component alloy has a wider application prospect in the fields of aerospace and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of multi-component alloys, and relates to a high-strength and high-elongation multi-component alloy and a preparation method thereof. Background Art

[0002] Nickel and nickel alloys are widely used in aerospace, ordnance, chemical industry, medical applications, and marine engineering due to their excellent properties. For example, nickel alloys have excellent resistance to chloride ion corrosion and can be used for a long time under extremely harsh environmental conditions, especially suitable for corrosive environments such as seawater. Their high strength, radiation resistance, and good high-temperature performance make them key materials in high-tech fields such as missile fins, engine turbine blades, and aircraft structural components.

[0003] Nickel alloys have many advantages such as high strength, good high-temperature performance, strong resistance to thermal fatigue, and corrosion resistance in extreme environments, and are widely used in key parts such as aeroengines, spacecraft structural components, and thermal protection systems. As early as the mid-20th century, the United States took the lead in researching the application of nickel alloys in the aviation field and developed a series of nickel-based alloy materials such as Inconel 718. In the temperature range of -253°C to 650°C, its tensile strength can reach 1290 MPa and the yield strength reaches 1030 MPa, which is widely used in key components such as compressor disks and blades of aeroengines.

[0004] Since the 1970s, domestic research and production have mainly focused on imitating and improving foreign mature alloy systems, such as the research and production of alloys such as GH4169 (corresponding to foreign Inconel 718). However, with the advancement of aerospace technology towards higher performance and more complex working conditions, higher requirements are placed on the performance of nickel alloys. In the development of hypersonic aircraft, aeroengines pursue a higher thrust-to-weight ratio, requiring materials to have higher strength and fatigue resistance. Most of the existing common nickel-based alloys are strengthened by γ' phase and can only meet the use requirements to a certain extent. However, with the further development of aerospace technology, nickel-based alloys cannot meet higher performance requirements.

[0005] Therefore, it is necessary to provide a high-strength and high-elongation multi-component alloy and a preparation method thereof. Based on the multi-component and multi-component coupling strengthening mechanism and combined with the preparation method, the strength and toughness of the multi-component alloy are further improved and an excellent balance is achieved, which strongly promotes a new round of application expansion of multi-component alloys in the aerospace field. Summary of the Invention

[0006] In order to overcome the problems in the background art, the present invention achieves multi-phase synergistic effects through the coupled and coordinated regulation of composition and process, enabling the alloy to precipitate and toughen the μ phase, while avoiding the decomposition of the strengthening phase BCC, and enabling the FCC matrix of the alloy to assist the μ phase in toughening, thereby making the alloy have relatively excellent comprehensive properties.

[0007] To achieve the above object, the present invention is realized through the following technical solutions:

[0008] On the one hand, the present invention provides a multi-component alloy with high strength and high elongation. The composition of the multi-component alloy by mass fraction includes: Al: 3.5 - 7.2%, Co: 19.9 - 23.3%, Cr: 12.3 - 16.5%, Fe: 22.5 - 26.2%, W: 9.6 - 14.2%, and the balance is Ni and inevitable impurities.

[0009] Preferably, the tensile strength of the multi-component alloy is greater than 1600 MPa, the yield strength is greater than 1100 MPa, and the fracture elongation is greater than 15%.

[0010] On the other hand, the present invention provides a preparation method of the above multi-component alloy. The preparation method includes the following steps:

[0011] (1) Using elemental metals as raw materials, mixing and melting the raw material elemental metals to obtain a multi-component alloy ingot;

[0012] (2) Performing homogenization treatment on the multi-component alloy ingot obtained in step (1);

[0013] (3) Performing multi-pass forging on the homogenized multi-component alloy ingot obtained in step (2) to obtain a forged alloy;

[0014] (4) Performing segmented heat treatment on the hot-worked alloy obtained in step (3) to obtain a multi-component alloy with high strength and high elongation.

[0015] Preferably, in step (1), the melting process is carried out with turning over, the number of turning-over melting times is 2 - 4 times, the time for each turning-over melting is 3 - 5 min, and the melting temperature is 3000 - 3500 °C.

[0016] Preferably, in step (2), the homogenization treatment temperature is 1000 - 1200 °C, and the holding time is 6 - 12 h.

[0017] Preferably, the multi-pass forging in step (3) includes cogging and hot rolling. The temperature of cogging is 1200 °C, the hot rolling temperature is 1050 °C, the single-pass rolling deformation amount ≤ 10%, and the cumulative hot rolling deformation amount ≥ 60%.

[0018] Preferably, the segmented heat treatment in step (4) specifically includes: holding the hot-worked alloy at 500 - 600 °C for 1 - 4 h, then heating the hot-worked alloy to 800 - 900 °C and holding for 0.5 - 3 h, and finally air-cooling the hot-worked alloy.

[0019] The present invention regulates the precipitation toughening μ-phase through the coupling effect of composition and process. In the present invention, the composition of the multi-component alloy is located at the initial precipitation element concentration of the μ-phase under the heat treatment temperature, ensuring the nano-precipitation of the toughening μ-phase while avoiding the decomposition of the strengthening phase BCC, and the matrix FCC assists the μ-phase toughening to achieve the multi-phase synergistic effect. The preparation method in the present invention ensures the stable precipitation of the toughening μ-phase in the multi-component alloy while preventing its excessive growth from damaging the nanostructure, achieving the coupling regulation of composition and process for the multi-phase synergistic effect.

[0020] Advantages of the present invention:

[0021] 1. By optimizing the design of the alloy element composition and combining with the corresponding preparation method, the present invention regulates through the coupling effect of composition and process. While ensuring the stable precipitation of the toughening μ-phase, it avoids the decomposition of the strengthening phase BCC and the damage of the nanostructure caused by the excessive growth of the μ-phase, thereby realizing the multi-phase synergistic effect of the BCC phase, FCC phase, and μ-phase, and enabling the prepared alloy to have relatively excellent comprehensive properties.

[0022] 2. For the alloy prepared by the present invention, the tensile strength can reach above 1600 MPa, the yield strength can reach above 1100 MPa, and the fracture elongation rate can reach above 15%. The alloy has excellent comprehensive mechanical properties. Description of the drawings

[0023] Figure 1 It is the SEM diagram of the multi-component alloy prepared by the present invention. Specific embodiments

[0024] The following further describes the present invention in detail with reference to the drawings and specific embodiments, but the protection scope of the present invention is not limited to the content described.

[0025] The alloy components of the examples and comparative examples of the present invention are shown in Table 1

[0026] Table 1

[0027]

[0028] Example 1

[0029] A high-strength and high-elongation multi-component alloy in this example, its preparation process is as follows:

[0030] (1) Weigh high-purity aluminum, cobalt, chromium, iron, tungsten, and nickel particles (purity ≥ 99%) as raw materials according to Table 1, add the raw materials into a vacuum arc melting furnace, and use vacuum arc melting to turn over and melt 3 times at 3200 °C (each melting for 4 min) to obtain a multi-component alloy ingot.

[0031] (2) Homogenize the multi-component alloy ingot by holding it at 1200 °C for 6 h.

[0032] (3) Perform cogging forging on the homogenized multi-component alloy ingot at 1200 °C to obtain a rod-shaped sample with a length of 300 mm, a width of 60 mm, and a thickness of 40 mm. Subsequently, hot-roll the rod-shaped sample at 1050 °C with a deformation of 10% per pass and a total deformation of 60% to obtain a forged alloy sample.

[0033] (4) Heat-treat the forged alloy sample in a vacuum tube furnace at 550 °C for 2 h. Subsequently, raise the temperature of the vacuum tube furnace to 850 °C and hold for 3 h. Finally, air-cool the forged alloy sample to obtain a multi-component alloy.

[0034] Cut mechanical property test samples from the multi-component alloy prepared in this example. The tensile test sample is a plate-shaped sample with a gauge length of 25 mm, a width of 5 mm, and a thickness of 2 mm, and perform mechanical property tests on the samples.

[0035] In this example, the mechanical property test results of the multi-component alloy samples are shown in Table 2.

[0036] Observe the microstructure of the multi-component alloy samples prepared in this example using a scanning electron microscope. The results are as Figure 1 shown.

[0037] Through Figure 1 It can be seen that in the multi-component alloy prepared in this example, the structure contains three phase components: nanoscale μ particles, large-sized BCC particles, and FCC matrix. Among them, the large-sized BCC particles can improve the strength of the alloy, while the matrix FCC and nanoscale μ particles synergistically toughen, which can effectively hinder the propagation of cracks and improve the fracture elongation rate of the alloy.

[0038] Example 2

[0039] A high-strength and high-elongation multi-component alloy in this example is prepared as follows:

[0040] (1) Weigh high-purity aluminum, cobalt, chromium, iron, tungsten, and nickel particles (purity ≥ 99%) as raw materials according to Table 1. Add the raw materials into a vacuum arc melting furnace and perform vacuum arc melting to turn over and melt 2 times (3 min each time) at 3500 °C to obtain a multi-component alloy ingot.

[0041] (2) Homogenize the multi-component alloy ingot by holding it at 1000 °C for 12 h.

[0042] (3) The homogenized multi-component alloy ingots are subjected to cogging forging at 1200 °C to obtain rod-shaped samples with a length of 300 mm, a width of 60 mm, and a thickness of 40 mm. Subsequently, the rod-shaped samples are hot-rolled at 1050 °C with a deformation per pass of 8% and a total deformation of 80% to obtain forged alloy samples.

[0043] (4) The forged alloy samples are heat-treated in a vacuum tube furnace at 500 °C for 4 h. Subsequently, the temperature of the vacuum tube furnace is raised to 800 °C and held for 2.5 h. Finally, the forged alloy samples are air-cooled to obtain multi-component alloys.

[0044] Mechanical property test samples are cut from the multi-component alloys prepared in this example. Among them, the tensile test samples are plate-shaped samples with a gauge length of 25 mm, a width of 5 mm, and a thickness of 2 mm, and the mechanical properties of the samples are tested.

[0045] In this example, the mechanical property test results of the multi-component alloy samples are shown in Table 2.

[0046] Example 3

[0047] A high-strength and high-elongation multi-component alloy in this example is prepared as follows:

[0048] (1) Weigh high-purity aluminum, cobalt, chromium, iron, tungsten, and nickel particles (purity ≥ 99%) as raw materials according to Table 1. Add the raw materials into a vacuum arc melting furnace and repeatedly melt them 4 times (each melting for 5 min) at 3000 °C by vacuum arc melting to obtain multi-component alloy ingots.

[0049] (2) The multi-component alloy ingots are held at 1100 °C for 8 h for homogenization treatment.

[0050] (3) The homogenized multi-component alloy ingots are subjected to cogging forging at 1200 °C to obtain rod-shaped samples with a length of 300 mm, a width of 60 mm, and a thickness of 40 mm. Subsequently, the rod-shaped samples are hot-rolled at 1050 °C with a deformation per pass of 5% and a total deformation of 70% to obtain hot-worked alloy samples.

[0051] (4) The hot-worked alloy samples are heat-treated in a vacuum tube furnace at 600 °C for 1 h. Subsequently, the temperature of the vacuum tube furnace is raised to 900 °C and held for 0.5 h. Finally, the hot-worked alloy samples are air-cooled to obtain multi-component alloys.

[0052] Mechanical property test samples are cut from the multi-component alloys prepared in this example. Among them, the tensile test samples are plate-shaped samples with a gauge length of 25 mm, a width of 5 mm, and a thickness of 2 mm, and the mechanical properties of the samples are tested.

[0053] In this embodiment, the mechanical property test results of the multi-component alloy samples are shown in Table 2.

[0054] Comparative Example 1

[0055] In this comparative example, the multi-component alloy was prepared by the same method as in Example 1, except that: the components of the multi-component alloy were different, as shown in Table 1 specifically.

[0056] Mechanical property test samples were cut from the multi-component alloy prepared in this comparative example. Among them, the tensile test sample was a plate-shaped sample with a gauge length of 25 mm, a width of 5 mm, and a thickness of 2 mm, and the mechanical properties of the sample were tested.

[0057] In this comparative example, the mechanical property test results of the multi-component alloy samples are shown in Table 2.

[0058] Comparative Example 2

[0059] In this comparative example, the multi-component alloy was prepared by the same method as in Example 1, except that: the components of the multi-component alloy were different, as shown in Table 1 specifically.

[0060] Mechanical property test samples were cut from the multi-component alloy prepared in this comparative example. Among them, the tensile test sample was a plate-shaped sample with a gauge length of 25 mm, a width of 5 mm, and a thickness of 2 mm, and the mechanical properties of the sample were tested.

[0061] In this comparative example, the mechanical property test results of the multi-component alloy samples are shown in Table 2.

[0062] Comparative Example 3

[0063] In this comparative example, the multi-component alloy was prepared by the same method as in Example 1, except that: the components of the multi-component alloy were different, as shown in Table 1 specifically.

[0064] Mechanical property test samples were cut from the multi-component alloy prepared in this comparative example. Among them, the tensile test sample was a plate-shaped sample with a gauge length of 25 mm, a width of 5 mm, and a thickness of 2 mm, and the mechanical properties of the sample were tested.

[0065] In this comparative example, the mechanical property test results of the multi-component alloy samples are shown in Table 2.

[0066] Comparative Example 4

[0067] In this comparative example, the multi-component alloy was prepared by the same method as in Example 1, except that: the components of the multi-component alloy were different, as shown in Table 1 specifically.

[0068] Mechanical property test samples were cut from the multi-component alloy prepared in this comparative example. Among them, the tensile test sample was a plate-shaped sample with a gauge length of 25 mm, a width of 5 mm, and a thickness of 2 mm, and the mechanical properties of the sample were tested.

[0069] In this comparative example, the mechanical property test results of the multi-component alloy samples are shown in Table 2.

[0070] Comparative Example 5

[0071] This comparative example uses the same method as Example 1 to prepare the multi-component alloy, with the difference that: the components of the multi-component alloy are different, as specifically shown in Table 1.

[0072] Mechanical property test samples are cut from the multi-component alloy prepared in this comparative example. Among them, the tensile test sample is a plate-shaped sample with a gauge length of 25 mm, a width of 5 mm, and a thickness of 2 mm, and the mechanical properties of the sample are tested.

[0073] In this comparative example, the mechanical property test results of the multi-component alloy samples are shown in Table 2.

[0074] Table 2

[0075] Tensile strength (MPa) Yield strength (MPa) Elongation rate (%) Example 1 1695 1125 16 Example 2 1659 1107 16 Example 3 1612 1113 16 Comparative example 1 881 585 14 Comparative example 2 786 593 14 Comparative example 3 712 572 15 Comparative example 4 913 654 13 Comparative example 5 842 566 14

[0076] It can be seen from Table 2 that for the multi-component alloy samples prepared in Examples 1-3 of the present invention, the tensile strength, yield strength, and elongation at break are all improved compared with Comparative Examples 1-5. Among them, the tensile strength and yield strength are significantly improved because the present invention regulates the precipitation and toughening of the μ phase through the coupling effect of composition-process, and avoids the decomposition of the strengthening phase BBC. At the same time, the matrix FCC assists the μ phase in toughening, achieving a multi-phase synergistic effect, so that the comprehensive performance of the alloy is improved.

[0077] In summary, through the coupling effect of composition-process, the present invention can ensure the stable nano-precipitation of the toughening μ phase, avoid the decomposition of the strengthening phase BCC and the overgrowth of the μ phase from damaging the nano-structure. At the same time, the matrix FCC phase assists the μ phase in toughening, achieving a multi-phase synergistic effect, so that the multi-component alloy of the present invention has excellent comprehensive mechanical properties and broad application prospects in the aerospace field.

[0078] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and are not restrictive. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made in form and details without departing from the scope defined by the claims of the present invention.

Claims

1. A high-strength, high-elongation multi-component alloy, characterized in that: The multi-component alloy comprises, by mass fraction, 3.5-7.2% Al, 19.9-23.3% Co, 12.3-16.5% Cr, 22.5-26.2% Fe, 9.6-14.2% W, and the remainder is Ni and unavoidable impurities.

2. The method for preparing a high-strength, high-elongation multi-component alloy according to claim 1, characterized in that: The preparation method comprises the following steps: (1) using single metal as raw material, mixing and smelting the raw single metal to obtain a multi-component alloy ingot; (2) homogenizing the multi-component alloy ingot obtained in step (1); (3) performing multi-fire forging on the multi-component alloy ingot after homogenization treatment in step (2) to obtain a forged alloy; (4) performing segmented heat treatment on the hot-worked alloy obtained in step (3) to obtain a high-strength, high-elongation multi-component alloy.

3. The preparation method according to claim 2, characterized in that: In the step (1), the smelting process is performed by turning over the steel sheet for 2-4 times, each time for 3-5 minutes, and the smelting temperature is 3000-3500°C.

4. The preparation method according to claim 2, characterized in that: In the step (2), the homogenization temperature is 1000-1200° C. and the insulation time is 6-12 hours.

5. The preparation method according to claim 2, characterized in that: The multi-fire forging in step (3) includes split forging and hot rolling. The split forging temperature is 1200° C., the hot rolling temperature is 1050° C., the single rolling deformation is ≤10%, and the hot rolling cumulative deformation is ≥60%.

6. The preparation method according to claim 2, characterized in that: The segmented heat treatment in step (4) specifically includes: keeping the hot-worked alloy at 500-600°C for 1-4 hours, then heating the hot-worked alloy to 800-900°C and keeping it for 0.5-3 hours, and finally air-cooling the hot-worked alloy.

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