High-strength and high-toughness al-co-cr-nb-ni nickel-based multi-main-element alloy in heat-treated state, preparation method and application thereof

Abstract

This invention provides a high-strength and high-toughness Al-Co-Cr-Nb-Ni nickel-based multi-principal-element alloy in a heat-treated state, its preparation method, and its applications. The high-strength and high-toughness Al-Co-Cr-Nb-Ni nickel-based multi-principal-element alloy in a heat-treated state has the general formula Al... a Co b Cr c Nb d Ni e The alloy comprises 5% ≤ a ≤ 6.5%, 5% ≤ b ≤ 6.5%, 5% ≤ c ≤ 6.5%, 5% ≤ d ≤ 6.5%, and 75% ≤ e ≤ 80%, with a + b + c + d + e = 100%. a, b, c, d, and e represent the molar percentages of the corresponding elements. This alloy is prepared using a thermomechanical process including solution treatment, cold rolling, low-temperature annealing, and aging. The alloy exhibits extremely high tensile strength and yield strength in the heat-treated state while maintaining good elongation at break, achieving an excellent balance between strength and toughness.

Description

Technical Field

[0001] This invention relates to alloy technology, and more particularly to a high-strength and high-toughness Al-Co-Cr-Nb-Ni nickel-based multi-principal-element alloy in a heat-treated state, its preparation method, and its applications. Background Technology

[0002] With the development of modern industrial technology, aerospace, nuclear power, and other fields have placed increasingly stringent demands on the performance of key structural materials under extreme service environments. Traditional single-phase face-centered cubic (FCC) multi-principal element alloys possess excellent room-temperature fracture toughness due to their inherent multi-principal element effect and highly symmetrical crystal structure. However, the low room-temperature yield strength of these alloys makes them unsuitable for high-load bearing, limiting their widespread application in engineering structures. To achieve a synergistic improvement in alloy strength and ductility, introducing a second phase into the FCC matrix through compositional design and alloying is currently the core strategy. Adding large atomic radius Al and Nb elements to nickel-based multi-principal element alloys not only produces significant solid solution strengthening and precipitation strengthening effects but also effectively improves the alloy's high-temperature stability, oxidation resistance, and corrosion resistance.

[0003] During the casting and solidification stages of an alloy, elemental segregation easily occurs within the alloy due to factors such as cooling rate, leading to the formation of coarse, hard, and brittle phases in the matrix. These hard and brittle phases readily become stress concentration sources, causing a sharp deterioration in the alloy's plasticity and fracture toughness. By employing specific mechanical heat treatment processes, the internal microstructure of the alloy can be adjusted, eliminating these coarse, hard, and brittle phases. Simultaneously, nano-reinforcing phases precipitate in the matrix, improving the alloy's fracture toughness while preserving its strength, thus achieving a synergistic improvement in both strength and plasticity.

[0004] In summary, there is an urgent need to develop a novel nickel-based multi-principal element alloy based on the synergistic effect of alloying design and thermomechanical treatment. By eliminating the hard and brittle phases and introducing strengthening phases, the strength and ductility of the alloy can be synergistically improved to meet the demands of modern industry for high-strength, high-toughness, and comprehensive mechanical properties of metallic structural materials. Summary of the Invention

[0005] The purpose of this invention is to address the problems of low room temperature yield strength in traditional single-phase face-centered cubic multi-principal alloys and the tendency to form coarse, hard, and brittle phases during casting, leading to a sharp deterioration in plasticity and fracture toughness. This invention proposes a high-strength, high-toughness Al-Co-Cr-Nb-Ni nickel-based multi-principal alloy in a heat-treated state. Through alloy composition design and thermomechanical treatment processes, this nickel-based multi-principal alloy achieves extremely high tensile strength and yield strength while maintaining good fracture elongation, realizing an excellent balance between strength and toughness. It has broad application prospects in engineering fields.

[0006] It should be noted that, in this invention, unless otherwise specified, the specific meaning of "comprising" in relation to composition and description includes both open-ended meanings such as "comprising," "including," etc., and closed-ended meanings such as "composed of," "consisting of," etc., and similar meanings.

[0007] To achieve the above objectives, the technical solution adopted by this invention is: a high-strength and high-toughness Al-Co-Cr-Nb-Ni nickel-based multi-principal-element alloy under heat treatment, with the general formula Al a Co b Cr c Nb d Ni e The molar percentages are 5% ≤ a ≤ 6.5%, 5% ≤ b ≤ 6.5%, 5% ≤ c ≤ 6.5%, 5% ≤ d ≤ 6.5%, and 75% ≤ e ≤ 80%, and a + b + c + d + e = 100%. a, b, c, d, and e are the molar percentages of the corresponding elements.

[0008] Furthermore, the general formula Al a Co b Cr c Nb d Ni e In the given information, a=b=c=d.

[0009] Furthermore, the general formula Al a Co b Cr c Nb d Ni e In the equation, a=b=c=d=(100-e) / 4.

[0010] Furthermore, the high-strength and high-toughness Al-Co-Cr-Nb-Ni nickel-based multi-principal-element alloy in the heat-treated state has tensile strength, yield strength and elongation at break of 1902~1968 MPa, 1510~1626 MPa and 6.5~10.2%, respectively.

[0011] Another objective of this invention discloses a method for preparing a high-strength and high-toughness Al-Co-Cr-Nb-Ni nickel-based multi-principal-element alloy in a heat-treated state, comprising the following steps:

[0012] Step 1: Grind, clean, and dry the Al, Co, Cr, Nb, and Ni metallic raw materials;

[0013] Step 2: Weigh each elemental metal raw material according to the general formula;

[0014] Step 3: Under a protective atmosphere, Ti elemental is first melted to remove residual oxygen, and then the weighed Al, Co, Cr, Nb and Ni elemental raw materials are melted to obtain nickel-based multi-principal element alloy ingots.

[0015] Step 4: Perform thermomechanical treatment on the nickel-based multi-principal alloy ingot. The thermomechanical treatment includes the following steps performed in sequence: solution treatment, cold rolling treatment, low-temperature annealing treatment, and aging treatment.

[0016] Furthermore, the purity of the Al, Co, Cr, Nb and Ni metallic raw materials is not less than 99.95 wt.%.

[0017] Furthermore, in step one, the oxide scale and impurities on the surface of Al, Co, Cr, Nb and Ni metal elemental raw materials are polished clean and ultrasonically cleaned. After the required elemental raw materials are cleaned, they are dried and placed into sealed bags for later use.

[0018] Furthermore, in step two, Ti metal elemental is weighed separately for later use, and the amount of Ti metal elemental used should be such that excess oxygen is removed as much as possible.

[0019] Further, in step three, the weighed elemental raw materials Al, Co, Cr, Nb, and Ni are placed in a copper crucible in the electric arc melting furnace, while elemental Ti is placed in a separate copper crucible; the vacuum chamber is closed, and the mechanical pump and pre-evacuation valve are turned on sequentially. After 30-60 seconds, the shut-off valve and digital vacuum gauge are turned on; wait until the digital vacuum gauge reading is 3 × 10⁻⁶. 0 ~3.5×10 0 After pa, sequentially open the main pumping valve, close the pre-pumping valve, and start the molecular pump; wait until the digital vacuum gauge reading is 2.5 × 10 -3 ~3×10 -3 After pa, the digital vacuum gauge, main pump valve and molecular pump are closed in sequence; after the molecular pump speed reaches 0, the shut-off valve is closed and the charging valve is opened to fill the vacuum chamber with protective gas to -0.06~-0.04MPa; before the nickel-based multi-principal alloy is smelted, Ti element is smelted first to remove excess oxygen, and then the nickel-based multi-principal alloy is smelted to obtain nickel-based multi-principal alloy ingots.

[0020] Furthermore, in step three, when smelting Ti, the number of smelting passes is 2 to 4, and the smelting time for each pass is 50 to 70 seconds, in order to remove excess oxygen as much as possible.

[0021] Furthermore, in step three, when smelting Al, Co, Cr, Nb and Ni metallic raw materials, the materials are repeatedly turned and smelted 5 to 7 times, with each smelting time being 90 to 120 seconds.

[0022] Furthermore, in step three, the Al, Co, Cr, Nb and Ni metallic raw materials are placed in the melting crucible in order of increasing melting point.

[0023] Further, in step four, the solution treatment temperature is 1050~1250℃, and the time is 1~4 h. Preferably, the solution treatment temperature is 1200℃, and the time is 2 h.

[0024] Furthermore, in step four, the heating rate of the solution treatment is 6~10℃ / min.

[0025] Furthermore, in step four, the deformation amount of the cold rolling process is 75% to 85%. Preferably, the deformation amount of the cold rolling process is 80%.

[0026] Furthermore, in step four, the low-temperature annealing temperature is 750~950℃, and the time is 0.5~8.5 h. Preferably, the low-temperature annealing temperature is 900℃, and the time is 1 h.

[0027] Furthermore, in step four, the heating rate of the low-temperature annealing is 3~5℃ / min.

[0028] Furthermore, in step four, the aging treatment temperature is 650~750℃, and the time is 3.5~4.5 h. Preferably, the aging treatment temperature is 700℃, and the time is 4 h.

[0029] Furthermore, in step four, water quenching is performed after the solution treatment and after the low-temperature annealing treatment.

[0030] Furthermore, in step four, during the cold rolling process, the amount of cold rolling each time is 0.08~0.12 mm, and the rolling is repeated 2~4 times.

[0031] Another objective of this invention is to disclose the application of a high-strength and high-toughness Al-Co-Cr-Nb-Ni nickel-based multi-principal-element alloy in a heat-treated state in the field of high-load-bearing components, including aerospace landing gear components, high thrust-to-weight ratio engine fasteners, and long-life compact drive shafts.

[0032] The thermomechanically treatable, high-strength, high-toughness Al-Co-Cr-Nb-Ni nickel-based multi-principal-element alloy of this invention is achieved through precise compositional design (general formula Al...). a Co b Cr c Nb d Ni eThe alloy, with a Ni content as high as 75-80% and Al, Co, Cr, and Nb each accounting for 5-6.5%, combined with a systematic thermomechanical treatment process (solution treatment + large deformation cold rolling + low temperature annealing + aging treatment), effectively solves the problems of low strength and poor toughness caused by casting hard and brittle phases in existing single-phase face-centered cubic multi-principal element alloys. The resulting advantages include:

[0033] 1. The as-cast phase structure of this nickel-based multi-principal alloy consists of a single FCC phase, exhibiting a typical dendritic and interdendritic microstructure. This nickel-based multi-principal alloy can be further strengthened through thermomechanical treatment and exhibits an extremely excellent balance between tensile strength and fracture toughness. The tensile strength, yield strength, and elongation at break are 1902~1968 MPa, 1510~1626 MPa, and 6.5~10.2%, respectively.

[0034] 2. Compared with high-entropy alloys with a single face-centered cubic solid solution structure, the nickel-based multi-principal element alloy not only has excellent mechanical properties, but also has advantages such as good castability and low casting defects.

[0035] 3. The nickel-based multi-principal alloy of the present invention contains metallic elements such as Al and Nb, which not only provide solid solution strengthening through alloying, but also improve the high-temperature stability, wear resistance and oxidation resistance of the nickel-based multi-principal alloy due to its inherent properties. Therefore, it has broad application prospects in the engineering field.

[0036] In summary, the thermomechanically treatable high-strength and high-toughness Al-Co-Cr-Nb-Ni alloy of this invention is a nickel-based multi-principal-element alloy with excellent strength and toughness. This nickel-based multi-principal-element alloy not only possesses excellent strength and toughness, but also exhibits potential for superior properties such as high-temperature stability, wear resistance, and oxidation resistance. Therefore, it is expected to be widely used in engineering fields. Attached Figure Description

[0037] Figure 1 The Al6Co6Cr6Nb6Ni prepared in Example 1 of this invention 76 Microstructure of nickel-based multi-principal-element alloys in the as-cast state;

[0038] Figure 2 The Al6Co6Cr6Nb6Ni prepared in Example 1 of this invention 76 XRD patterns of nickel-based multi-principal element alloys in the as-cast state;

[0039] Figure 3 The Al6Co6Cr6Nb6Ni prepared in Example 1 of this invention 76Stress-strain curves of nickel-based multi-principal-element alloys under room temperature tensile engineering in the as-cast state and under thermomechanical treatment (1200℃×2h+80% cold rolling+900℃×1h / 700℃×4h);

[0040] Figure 4 The Al prepared in Example 2 of this invention 5.5 Co 5.5 Cr 5.5 Nb 5.5 Ni 78 Microstructure of nickel-based multi-principal-element alloys in the as-cast state;

[0041] Figure 5 The Al prepared in Example 2 of this invention 5.5 Co 5.5 Cr 5.5 Nb 5.5 Ni 78 XRD patterns of nickel-based multi-principal element alloys in the as-cast state;

[0042] Figure 6 The Al prepared in Example 2 of this invention 5.5 Co 5.5 Cr 5.5 Nb 5.5 Ni 78 Stress-strain curves of nickel-based multi-principal-element alloys under as-cast and thermomechanical treatment (1100℃×3h+80% cold rolling+800℃×8h / 700℃×4h) at room temperature. Detailed Implementation

[0043] The present invention will be further described below with reference to embodiments. The description of the technical features described below is based on representative embodiments and specific examples of the present invention, but the present invention is not limited to these embodiments and specific examples. It should be noted that:

[0044] Unless otherwise stated, all units used in this specification are international standard units, and all numerical values ​​and ranges appearing in this invention should be understood to include systematic errors that are unavoidable in industrial production.

[0045] In this specification, the range of values ​​referred to as "value A to value B" refers to the range including the endpoint values ​​A and B.

[0046] In this specification, the numerical range indicated by "above" or "below" refers to the numerical range that includes the stated number.

[0047] In this specification, the word "may" has two meanings: to perform a certain process and not to perform a certain process.

[0048] In this specification, the terms "optional" or "optional" are used to indicate the use or omission of certain substances, components, procedures, application conditions, etc.

[0049] In this instruction manual, when "room temperature" or "room temperature" is used, the temperature can be 15-25℃.

[0050] Unless otherwise specified, all reagents or instruments used in this instruction manual are commercially available products.

[0051] Example 1

[0052] This embodiment discloses a thermomechanically treatable, high-strength, high-toughness Al-Co-Cr-Nb-Ni nickel-based multi-principal-element alloy material with the general formula Al6Co6Cr6Nb6Ni. 76 .

[0053] In this embodiment, the preparation method of a thermomechanically treatable high-strength and high-toughness Al-Co-Cr-Nb-Ni nickel-based multi-principal-element alloy material includes the following steps:

[0054] Step 1: Polishing and Cleaning

[0055] The oxide scale and impurities on the surface of Al, Co, Cr, Nb, and Ni elemental raw materials with a purity of 99.95 wt.% were polished clean and ultrasonically cleaned. After cleaning, the required elemental raw materials were dried and placed into sealed bags for later use.

[0056] Step 2: Ingredient Preparation

[0057] Based on a total ingot mass of 70 g, the required masses of each elemental material were determined by converting the molar percentages of Al, Co, Cr, Nb, and Ni to mass percentages: Al: 1.939 g; Co: 4.234 g; Cr: 3.736 g; Nb: 6.675 g; Ni: 53.416 g. These were weighed using an electronic balance. 40 g of elemental Ti was also weighed for later use. All weighing errors were within ±0.001 g.

[0058] Step 3: Smelting

[0059] On one hand, the weighed metallic raw materials Al, Co, Cr, Nb, and Ni are placed into the crucible in order of increasing melting point. On the other hand, elemental Ti is placed separately in a separate copper crucible. The vacuum chamber is closed, and the mechanical pump and pre-evacuation valve are turned on sequentially. After 50 seconds, the shut-off valve and digital vacuum gauge are turned on; wait until the digital vacuum gauge reading reaches 3.2 × 10⁻⁶. 0 After pa, sequentially open the main molecular pumping valve, close the pre-pumping valve, and start the molecular pump. Wait until the digital vacuum gauge reading reaches 2.8 × 10⁻⁶. -3After reaching 0 MPa, the digital vacuum gauge, main pump valve, and molecular pump are closed sequentially. Once the molecular pump speed reaches 0, the shut-off valve is closed, and the charging valve is opened to fill the vacuum chamber with high-purity argon until the vacuum gauge reaches -0.05 MPa. Before melting the nickel-based multi-principal alloy, Ti ingots are melted three times, each melting time being 60 seconds, to remove excess oxygen as much as possible. Then, the nickel-based multi-principal alloy material is repeatedly turned and melted six times, each melting time being 100 seconds, ultimately yielding Al6Co6Cr6Nb6Ni in this embodiment. 76 Nickel-based multi-principal alloy button ingot.

[0060] Step 4: Thermomechanical treatment

[0061] The Al6Co6Cr6Nb6Ni obtained in this embodiment 76 Nickel-based multi-principal-element alloy button ingots were solution-treated at 1200℃ for 2 hours, followed by water quenching. After solution treatment, they were cold-rolled with a deformation of 80%, each cold rolling increment of 0.1 mm, repeated three times. Then, they underwent low-temperature annealing at 900℃ for 1 hour, followed by water quenching. Finally, they were subjected to low-temperature aging at 700℃ for 4 hours, followed by water quenching.

[0062] Figure 1 The Al6Co6Cr6Nb6Ni obtained in this embodiment 76 Microstructure of nickel-based multi-principal element alloy in the as-cast state. The alloy exhibits a typical dendritic and interdendritic microstructure, with uniformly distributed L12 phase and D0 phase within the dendrites. 22 The phase consists of a Nb-enriched Laves / δ hard and brittle phase formed between dendrites.

[0063] Figure 2 This embodiment demonstrates the Al6Co6Cr6Nb6Ni obtained. 76 The XRD pattern of the nickel-based multi-principal element alloy in the as-cast state shows that the content of the hard and brittle Laves / δ phase is too low, and the L12 phase and D0 phase are also present. 22 The phase is completely coherent with the FCC matrix, and the phase structure of the alloy in the as-cast state consists of a soft FCC single phase.

[0064] Figure 3 This embodiment demonstrates the Al6Co6Cr6Nb6Ni obtained. 76 The room temperature tensile stress-strain curves of the nickel-based multi-principal element alloy in the as-cast and thermomechanically treated states (1200℃×2h+80% cold-rolled+900℃×1h / 700℃×4h) are shown. It can be observed that this nickel-based multi-principal element alloy exhibits excellent thermomechanical deformation strengthening effect. After thermomechanical treatment, the tensile strength, yield strength, and elongation at break are 1968 MPa, 1626 MPa, and 6.5%, respectively, demonstrating extremely excellent mechanical properties.

[0065] Example 2

[0066] This embodiment discloses a high-strength, high-toughness Al-Co-Cr-Nb-Ni nickel-based multi-principal-element alloy material that can be thermomechanically treated, with the general formula Al 5.5 Co 5.5 Cr 5.5 Nb 5.5 Ni 78 .

[0067] In this embodiment, the preparation method of the thermomechanically treatable high-strength and high-toughness Al-Co-Cr-Nb-Ni nickel-based multi-principal-element alloy material is as follows:

[0068] Step 1: Polishing and Cleaning

[0069] The oxide scale and impurities on the surface of Al, Co, Cr, Nb, and Ni elemental raw materials with a purity of 99.95 wt.% were polished clean and ultrasonically cleaned. After cleaning, the required elemental raw materials were dried and placed into sealed bags for later use.

[0070] Step 2: Ingredient Preparation

[0071] Based on a total ingot mass of 70 g, the required mass of each elemental material was determined by converting the molar percentages of Al, Co, Cr, Nb, and Ni to mass percentages: Al: 1.776 g; Co: 3.880 g; Cr: 3.423 g; Nb: 6.117 g; Ni: 54.803 g. The materials were weighed using an electronic balance, and 40 g of Ti was weighed for later use, with an error within ±0.001 g.

[0072] Step 3: Smelting

[0073] On one hand, the weighed elemental metals Al, Co, Cr, Nb, and Ni are placed into the crucible in order of increasing melting point. On the other hand, elemental Ti is placed separately in a separate copper crucible. The vacuum chamber is closed, and the mechanical pump and pre-evacuation valve are turned on sequentially. After 50 seconds, the shut-off valve and digital vacuum gauge are turned on; wait until the digital vacuum gauge reading reaches 3.2 × 10⁻⁶. 0 After pa, sequentially open the main molecular pumping valve, close the pre-pumping valve, and start the molecular pump. Wait until the digital vacuum gauge reading reaches 2.8 × 10⁻⁶. -3After reaching 0 MPa, the digital vacuum gauge, main pump valve, and molecular pump are closed sequentially. Once the molecular pump speed reaches 0, the shut-off valve is closed, and the charging valve is opened to fill the vacuum chamber with high-purity argon until the vacuum gauge reaches -0.05 MPa. Before melting the nickel-based multi-principal alloy, Ti ingots are melted three times, each melting time being 60 seconds, to remove excess oxygen as much as possible. Then, the nickel-based multi-principal alloy material is repeatedly turned and melted six times, each melting time being 100 seconds, ultimately yielding the Al of this embodiment. 5.5 Co 5.5 Cr 5.5 Nb 5.5 Ni 78 Nickel-based multi-principal alloy button ingot.

[0074] Step 4: Thermomechanical treatment

[0075] The Al obtained in this embodiment 5.5 Co 5.5 Cr 5.5 Nb 5.5 Ni 78 Nickel-based multi-principal-element alloy button ingots were solution-treated at 1100℃ for 3 hours, followed by water quenching. After solution treatment, they were cold-rolled with a deformation of 80%, each cold rolling increment of 0.1 mm, repeated 3 times. Then, they underwent low-temperature annealing at 800℃ for 8 hours, followed by water quenching. Finally, they were subjected to low-temperature aging at 700℃ for 4 hours, followed by water quenching.

[0076] Figure 4 The Al obtained in this embodiment 5.5 Co 5.5 Cr 5.5 Nb 5.5 Ni 78 Microstructure of nickel-based multi-principal element alloy in the as-cast state. The alloy exhibits a typical dendritic and interdendritic microstructure, with uniformly distributed L12 phase and D0 phase within the dendrites. 22 The phase consists of a Nb-enriched Laves / δ hard and brittle phase formed between dendrites.

[0077] Figure 5 This embodiment demonstrates the Al obtained. 5.5 Co 5.5 Cr 5.5 Nb 5.5 Ni 78 The XRD pattern of the nickel-based multi-principal element alloy in the as-cast state is consistent with the phase structure of the nickel-based multi-principal element alloy in Example 1. This Al... 5.5 Co 5.5 Cr 5.5 Nb 5.5 Ni 78 The phase structure of nickel-based multi-principal alloys in the as-cast state is also composed of soft FCC single phases.

[0078] Figure 6 The Al obtained in this embodiment 5.5 Co 5.5 Cr 5.5 Nb 5.5 Ni 78 The room temperature tensile stress-strain curves of the nickel-based multi-principal element alloy in the as-cast and thermomechanically treated states (1100℃×3h+80% cold-rolled+800℃×8h / 700℃×4h) are presented. It can be seen that this nickel-based multi-principal element alloy also exhibits excellent thermomechanical deformation strengthening effect. After thermomechanical treatment, the tensile strength, yield strength, and elongation at break are 1902 MPa, 1510 MPa, and 10.2%, respectively, demonstrating extremely excellent mechanical properties. In summary, the nickel-based multi-principal element alloy of this invention exhibits excellent thermomechanical strengthening effect and has broad application prospects in the engineering field.

[0079] It is evident that the nickel-based multi-principal alloy of this invention can be further strengthened through thermomechanical processing, exhibiting high tensile strength and a good match between fracture toughness. The addition of Al and Nb elements effectively enhances the high-temperature stability, oxidation resistance, and corrosion resistance of this nickel-based multi-principal alloy.

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-strength and high-toughness Al-Co-Cr-Nb-Ni nickel-based multi-principal-element alloy in a heat-treated state, characterized in that, The general formula is Al a Co b Cr c Nb d Ni e The molar percentages are 5% ≤ a ≤ 6.5%, 5% ≤ b ≤ 6.5%, 5% ≤ c ≤ 6.5%, 5% ≤ d ≤ 6.5%, and 75% ≤ e ≤ 80%, and a + b + c + d + e = 100%. a, b, c, d, and e are the molar percentages of the corresponding elements.

2. The high-strength and high-toughness Al-Co-Cr-Nb-Ni nickel-based multi-principal-element alloy in the heat-treated state according to claim 1, characterized in that, The general formula Al a Co b Cr c Nb d Ni e In the equation, a=b=c=d=(100-e) / 4.

3. The high-strength and high-toughness Al-Co-Cr-Nb-Ni nickel-based multi-principal-element alloy in the heat-treated state according to claim 1, characterized in that, The high-strength and high-toughness Al-Co-Cr-Nb-Ni nickel-based multi-principal-element alloy in the heat-treated state has tensile strength, yield strength and elongation at break of 1902~1968 MPa, 1510~1626 MPa and 6.5~10.2%, respectively.

4. A method for preparing a high-strength and high-toughness Al-Co-Cr-Nb-Ni nickel-based multi-principal element alloy in the heat-treated state as described in any one of claims 1-3, characterized in that, Includes the following steps: Step 1: Grind, clean, and dry the Al, Co, Cr, Nb, and Ni metallic raw materials; Step 2: Weigh each elemental metal raw material according to the general formula; Step 3: Under a protective atmosphere, Ti elemental is first melted to remove residual oxygen, and then the weighed Al, Co, Cr, Nb and Ni elemental raw materials are melted to obtain nickel-based multi-principal element alloy ingots. Step 4: Perform thermomechanical treatment on the nickel-based multi-principal alloy ingot. The thermomechanical treatment includes the following steps performed in sequence: solution treatment, cold rolling treatment, low-temperature annealing treatment, and aging treatment.

5. The method for preparing the high-strength and high-toughness Al-Co-Cr-Nb-Ni nickel-based multi-principal element alloy in the heat-treated state according to claim 4, characterized in that, The purity of Al, Co, Cr, Nb and Ni metallic raw materials is not less than 99.95 wt.%.

6. The method for preparing a high-strength and high-toughness Al-Co-Cr-Nb-Ni nickel-based multi-principal-element alloy in the heat-treated state according to claim 4, characterized in that, In step three, the weighed elemental raw materials Al, Co, Cr, Nb, and Ni are placed in a copper crucible in the electric arc melting furnace, while elemental Ti is placed in a separate copper crucible. The vacuum chamber is closed, and the mechanical pump and pre-evacuation valve are turned on sequentially. After 30-60 seconds, the shut-off valve and digital vacuum gauge are turned on. The process continues until the digital vacuum gauge reading reaches 3 × 10⁻⁶. 0 ~3.5×10 0 After pa, sequentially open the main pumping valve, close the pre-pumping valve, and start the molecular pump; wait until the digital vacuum gauge reading is 2.5 × 10 -3 ~3×10 -3 After pa, the digital vacuum gauge, main pump valve and molecular pump are closed in sequence; after the molecular pump speed reaches 0, the shut-off valve is closed and the charging valve is opened to fill the vacuum chamber with protective gas to -0.06~-0.04MPa; before the nickel-based multi-principal alloy is smelted, Ti element is smelted first to remove excess oxygen, and then the nickel-based multi-principal alloy is smelted to obtain nickel-based multi-principal alloy ingots.

7. The method for preparing the high-strength and high-toughness Al-Co-Cr-Nb-Ni nickel-based multi-principal-element alloy in the heat-treated state according to claim 4, characterized in that, In step three, when smelting Ti, the number of smelting passes is 2 to 4, and the smelting time for each pass is 50 to 70 seconds; And / or, when smelting Al, Co, Cr, Nb and Ni metallic raw materials, repeatedly turn and smelt 5 to 7 times, with each smelting time being 90 to 120 seconds; And / or, the Al, Co, Cr, Nb and Ni metallic raw materials are placed in the melting crucible in order of increasing melting point.

8. The method for preparing the high-strength and high-toughness Al-Co-Cr-Nb-Ni nickel-based multi-principal element alloy in the heat-treated state according to claim 4, characterized in that, In step four, the solution treatment temperature is 1050~1250℃ and the time is 1~4 h; And / or, the heating rate of the solution treatment is 6~10℃ / min; And / or, the deformation amount of the cold rolling process is 75%~85%; And / or, the low-temperature annealing temperature is 750~950℃, and the time is 0.5~8.5 h; And / or, the heating rate of the low-temperature annealing is 3~5℃ / min; And / or, the aging treatment is performed at a temperature of 650~750℃ for a time of 3.5~4.5 h.

9. The method for preparing a high-strength and high-toughness Al-Co-Cr-Nb-Ni nickel-based multi-principal-element alloy in the heat-treated state according to claim 4, characterized in that, In step four, water quenching is performed after the solution treatment and after the low-temperature annealing. And / or, in the cold rolling process, the amount of cold rolling each time is 0.08~0.12 mm, and the rolling is repeated 2~4 times.

10. The application of the high-strength and high-toughness Al-Co-Cr-Nb-Ni nickel-based multi-principal-element alloy in the heat-treated state as described in any one of claims 1-3 in the field of high-load-bearing components.

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