Wide-temperature-range high-toughness multi-principal-element alloy, alloy plate and preparation method of alloy plate

Abstract

The invention discloses a wide-temperature-range high-toughness multi-principal-element alloy, an alloy plate and a preparation method of the alloy plate. The general formula of the alloy is Fe Ni Co < c > Al < d > Ta < e > M < f >, wherein M is selected from at least one of Si, B, P and C; a, b, c, d, e and f respectively represent atomic percentages of corresponding alloy elements, 35 < = a < = 45, 25 < = b < = 35, 15 < = c < = 25, 7 < = d < = 15, 0 lt; e < = 5, 0lt; f < = 2, 78 < = a + b + c < = 85, 0lt; e + f < = 5, and a + b + c + d + e + f = 100. The multi-principal-element alloy has the characteristics of high yield strength, high tensile strength and high elongation at room temperature, and can keep good mechanical property stability at extreme service environment temperature from low temperature to high temperature; the plastic processing capability is good, and complex processing can be carried out. The preparation method disclosed by the invention is simple in process, low in condition requirement, low in cost and suitable for industrial mass production, and raw materials are easy to obtain.

Description

Technical Field

[0001] The present invention belongs to the field of metal structural materials, and specifically relates to a high-strength and high-toughness multi-principal-element alloy in a wide temperature range, an alloy plate, and a preparation method thereof. Background Art

[0002] Human beings have never stopped changing the world and exploring the universe, and the increasingly complex and harsh application environment has posed a huge challenge to existing structural materials. The rapid development of the aerospace industry requires more powerful jet engines, which requires the use of new materials that are difficult to soften at higher temperatures. Fields such as deep-sea exploration and low-temperature superconductivity require structural materials with high low-temperature fracture toughness to ensure that they are not easy to break under low or even ultra-low temperature conditions. In order to realize the dream of manned moon landing and touching the depths of space, structural materials used for space exploration must be able to remain stable and resist impact in a space environment with huge temperature differences. With the advancement of industrial processes, the loads in the service environment will become more complex and extreme, which urgently requires tougher and higher-performance materials to meet these challenges.

[0003] At present, traditional high-performance metal materials have a narrow service temperature window, poor comprehensive performance, and cannot take into account the mechanical properties in different temperature ranges. For example, although most ultra-high-strength steels and high-strength titanium alloys have high strength at room temperature, they have poor deformation ability at low temperatures and show typical brittle fracture; while austenitic steels, low-temperature titanium alloys, etc. have excellent mechanical properties at low temperatures (77 K), but their strength at room temperature and high temperatures is low, which cannot meet the mechanical properties requirements of key aerospace components under extreme conditions. These evidences show that traditional composition and structural design are gradually unable to meet the urgent needs of the aerospace field for high-strength and tough structural materials with a wide temperature range. Therefore, establishing and developing new alloy design principles has become a necessary path to break through the bottleneck of existing technologies.

[0004] Since the concept of composition design such as high entropy alloys, multi-principal alloys, and complex component alloys was proposed, it has attracted widespread attention from researchers due to its superior mechanical, physical, chemical, and structural stability. Now researchers generally believe that high entropy alloys are single-phase or multi-phase solid solution alloys obtained by mixing at least 4 elements in an equimolar ratio or a near equimolar ratio. The emergence of multi-component alloys has created a new concept in alloy material design and has the potential to break through many performance limits of traditional materials. Because it can combine the advantages of multiple properties, it has application prospects in extreme environments and has great research significance. Modern industry has an increasingly urgent demand for high-performance soft magnetic materials serving in extreme environments (such as aerospace, advanced weapons manufacturing, etc.), while most traditional steels have shown that it is difficult to combine mechanical properties, machining properties, and wide temperature range performance.

[0005] As far as wide temperature range high strength and toughness structural metal materials are concerned, the alloy systems currently studied are mainly based on transition metal elements such as Fe, Co and Ni, and refractory metal elements such as Nb, Hf, Ta and W, supplemented by other alloy elements that can produce cocktail effects such as Al, Cu, Mn, Ti and Si, C, P, B and other metalloid elements. One or more of these elements are designed in a reasonable ratio. In recent years, with the in-depth attention paid to the performance research of multi-principal alloys, some component systems with mechanical properties have been developed, but there are few studies on the stability of mechanical properties and their application in a wide temperature range. The patent application with publication number CN201410466857.2 discloses a wide temperature range high strength constant elastic alloy and its preparation method. The alloy has high strength and low elastic modulus temperature coefficient in a wide temperature range (-60 ℃ ~ 400 ℃). The chemical composition of the alloy is FeNiCoTiAl-based. Through the optimization of alloying elements and the adjustment of the preparation process, the strength of the Fe-Ni-Co alloy is further improved in a wide temperature range, while the temperature coefficient of its elastic modulus is reduced. However, in the temperature range of -60 to 400 ° C, the tensile strength of the alloy is greater than 1350 MPa, and the maximum elongation at break is only greater than 2.5%. The extremely low elongation at break makes the alloy poor in complex structure processability and resistance to impact loads when used as a structural material. In addition, the patent application with publication number CN202410354165.2 discloses a high-damping TiZr-based high-entropy alloy with high strength and plasticity in a wide temperature range and a preparation method thereof, which is expected to become a damping structural material with integrated structural functions in high-temperature service environments. However, the room temperature tensile yield strength of the high-damping TiZr-based high-entropy alloy described in the alloy at room temperature is >850 MPa, the tensile strength is >900 MPa, and the tensile plasticity is >10%. However, the patent application only involves the design of alloy composition and does not involve the application exploration of soft magnetic components; in addition, the alloy disclosed in the patent application still has the disadvantages of excessive loss and difficulty in applying to high-frequency fields. The multi-principal alloy system reported in existing literature also has problems such as low alloy strength and high raw material cost. The performance is not enough to replace the existing industrial alloy grades, which limits the specific application of multi-principal alloys in extreme load environments.

[0006] In summary, the introduction of the alloy design concept of multi-principal alloys into the design of new wide temperature range high-strength and toughness alloys has profound academic research significance and application research value. The development of new multi-principal alloys with high yield strength, high tensile strength, high elongation at break, low cost and good strength-toughness matching in a wide temperature range through composition design is of great significance for solving the problem that alloys are difficult to have both strength and toughness, and for the development of structural materials for extreme load environments and the promotion and application of multi-principal alloys. Summary of the invention

[0007] The present invention aims to develop advanced structural materials for application environments with relatively harsh service conditions such as aerospace and advanced equipment manufacturing, introduces multi-scale structured structures such as ordered nano-precipitates, martensite and local composition fluctuations in the matrix of low stacking fault energy face-centered cubic single-phase multi-principal alloy, restricts the free path of dislocation movement, and designs a multi-principal alloy that greatly improves the strong plasticity of the single-phase multi-principal alloy in a wide temperature range. Specifically, the present invention discloses a multi-principal alloy system composed of Fe, Ni, Co, Al and Ta as main components, and a small amount of one or more of B, Si, P or C doped, and a method for preparing such an alloy system.

[0008] According to one aspect of the present invention, a wide temperature range high strength and toughness multi-principal alloy is provided, wherein the composition of the wide temperature range high strength and toughness multi-principal alloy satisfies the general formula Fe a Ni b Co c Al d Ta e M f , wherein M is selected from at least one of Si, B, P, and C; a, b, c, d, e, and f represent the atomic percentages of the corresponding alloying elements, 35≤a≤45, 25≤b≤35, 15≤c≤25, 7≤d≤15, 0 <e≤5,0<f≤2,78≤a+b+c≤85,0<e+f≤5,a+b+c+d+e+f =100。

[0009] Optionally, in the general formula, the value of a is independently selected from any value among 35.0, 35.5, 36.0, 36.5, 37.0, 37.5, 38.0, 38.5, 39.0, 39.5, 40.0, 40.5, 41.0, 41.5, 42.0, 42.5, 43.0, 43.5, 44.0, 44.5, 45.0, or a range between any two of them.

[0010] Optionally, in the general formula, the value of b is independently selected from any value among 25.0, 25.5, 26.0, 26.5, 27.0, 27.5, 28.0, 28.5, 29.0, 29.5, 30.0, 30.5, 31.0, 31.5, 32.0, 32.5, 33.0, 33.5, 34.0, 34.5, 35.0, or a range between any two of them.

[0011] Optionally, in the general formula, the value of c is independently selected from any value selected from 15.0, 15.5, 16.0, 16.5, 17.0, 17.5, 18.0, 18.5, 19.0, 19.5, 20.0, 20.5, 21.0, 21.5, 22.0, 22.5, 23.0, 23.5, 24.0, 24.5, 25.0, or a range between any two of them.

[0012] Optionally, in the general formula, the value of d is independently selected from any value among 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10.0, 10.5, 11.0, 11.5, 12.0, 12.5, 13.0, 13.5, 14.0, 14.5, 15.0, or a range between any two of them.

[0013] Optionally, in the general formula, the value of e is independently selected from any value among 0.01, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0 or any range between two of them.

[0014] Optionally, in the general formula, the value of f is independently selected from any value among 0.01, 0.5, 1.0, 1.5, 2.0 or any range between two of them.

[0015] According to the present invention, in order to balance the thermodynamic stability, alloy matrix and precipitate phase ratio, strength, elongation at break and other mechanical properties in alloy design, further optimization can be performed based on the above-mentioned limitation of the atomic percentage of alloy elements:

[0016] Preferably, in the general formula, 27≤b≤31;

[0017] Preferably, in the general formula, 15≤c≤18;

[0018] Preferably, in the general formula, 9≤d≤12;

[0019] Preferably, in the general formula, 2 <e≤3;

[0020] Preferably, in the general formula, 0 <f≤1;

[0021] Preferably, in the general formula, M is B and C.

[0022] Optionally, the wide temperature range multi-principal component alloy has a yield strength of 900-1200 MPa, a tensile strength of 1500-1900 MPa, and an elongation at break of more than 15% at room temperature; preferably, the multi-principal component alloy has a yield strength of more than 1150 MPa, a tensile strength of more than 1800 MPa, and an elongation at break of more than 20% at room temperature.

[0023] The yield strength of the wide temperature range multi-principal component alloy at 600°C is 600-900 MPa, the tensile strength is 900-1200 MPa, and the elongation at break is above 25%; preferably, the yield strength of the multi-principal component alloy at 600°C is above 800 MPa, the tensile strength is above 1000 MPa, and the elongation at break is above 25%.

[0024] The wide temperature range multi-principal component alloy has a yield strength of 400-700 MPa at 800°C, a tensile strength of 400-700 MPa, and an elongation at break of more than 25%; preferably, the multi-principal component alloy has a yield strength of more than 550 MPa at 800°C, a tensile strength of more than 600 MPa, and an elongation at break of more than 20%.

[0025] According to another aspect of the present invention, there is provided a method for preparing the wide temperature range high-strength and high-toughness multi-principal component alloy ingot as described above, comprising:

[0026] a) weighing alloy raw materials containing Fe, Ni, Co, Al, Ta and M according to the general formula and preparing the ingredients;

[0027] b) smelting the alloy raw materials, including melting, heat preservation, and cooling in an inert atmosphere to obtain the multi-principal alloy.

[0028] Optionally, in step b), the melting temperature is 1400-1700°C.

[0029] Optionally, the melting temperature is independently selected from any value among 1400°C, 1425°C, 1450°C, 1475°C, 1500°C, 1510°C, 1520°C, 1530°C, 1540°C, 1550°C, 1560°C, 1570°C, 1580°C, 1590°C, 1600°C, 1625°C, 1650°C, 1675°C, 1700°C, or any range therebetween.

[0030] Optionally, in step b), the insulation time is 10-20 min.

[0031] Optionally, the insulation time is independently selected from any value among 10 min, 11 min, 12 min, 13 min, 14 min, 15 min, 16 min, 17 min, 18 min, 19 min, 20 min, or any range value between two of them.

[0032] Optionally, in step b), the cooling time is 10-30 min.

[0033] Optionally, the cooling time is independently selected from any value among 10 min, 11 min, 12 min, 13 min, 14 min, 15 min, 16 min, 17 min, 18 min, 19 min, 20 min, 21 min, 22 min, 23 min, 24 min, 25 min, 26 min, 27 min, 28 min, 29 min, 30 min, or any range value between two of them.

[0034] In one embodiment, the method for preparing the wide temperature range high strength and toughness multi-principal alloy ingot comprises:

[0035] a1) weighing single element raw materials of Fe, Ni, Co, Al, Ta and M according to the ratio of the general formula;

[0036] b1) placing the alloy raw material in a smelting device, smelting it in an inert atmosphere, keeping it warm for 10-20 minutes after melting, and then pouring the molten alloy into a cooling mold and cooling it for 10-30 minutes, thereby obtaining an alloy ingot with uniform composition.

[0037] c1) subjecting the multi-principal alloy cast ingot to homogenization heat treatment at 1300-1400° C. for 3-12 hours, and water quenching to obtain an alloy ingot with uniform structure.

[0038] Optionally, in step b), the smelting is induction smelting, comprising: placing the alloy raw material in an induction smelting furnace, evacuating the furnace and then filling it with inert gas to 0.05-0.1 MPa, melting at 1500-1600°C and keeping the temperature for 10-20 min, and then transferring the alloy to a mold and cooling it for 10-30 min.

[0039] In one embodiment, the method for preparing the wide temperature range high strength and toughness multi-principal alloy ingot comprises:

[0040] a2) weighing compound raw materials containing Fe, Ni, Co, Al, Ta and M in proportion according to the general formula;

[0041] b2) Put the alloy raw materials into a crucible and place it in the induction coil of an induction melting furnace, and evacuate the vacuum to less than 1.0×10 -2 After the pressure reaches 0.05 MPa, the inert gas is filled in, and after melting, the temperature is kept for 10-20 min, and then the molten alloy is poured into a cooling mold and cooled for 10-30 min;

[0042] c2) subjecting the main alloy cast ingot to the steps of remelting, cooling, remelting and cooling in an induction melting furnace for at least three times, keeping the temperature for 10-20 minutes after melting, and then pouring the molten alloy into a cooling mold and cooling for 10-30 minutes to obtain an alloy ingot with uniform structure.

[0043] According to another aspect of the present invention, a method for preparing a multi-principal component alloy plate is provided. The multi-principal component alloy plate is prepared from the multi-principal component alloy ingot with high strength and toughness in a wide temperature range as described above.

[0044] According to another aspect of the present invention, there is provided a method for preparing the multi-principal alloy plate as described above, comprising:

[0045] d) hot rolling the alloy ingot at 1200-1300° C. with a rolling reduction of 20-30%, and cooling to obtain a preliminary rolled plate;

[0046] e) cold rolling the preliminary rolled plate at room temperature with a reduction of 80-90% to obtain a final rolled plate;

[0047] f) subjecting the final rolled plate to an annealing heat treatment at 1100-1300° C. for 10-30 min, and water quenching to obtain a preliminary heat-treated plate;

[0048] g) The primary heat-treated plate is subjected to a -196°C liquid nitrogen deep cryogenic treatment for 0-48 hours, and then taken out and the temperature is restored to room temperature to obtain a secondary heat-treated plate.

[0049] h) performing aging heat treatment at 600-800°C for 2-8 hours on the secondary heat treated plate, and water quenching to obtain a final plate.

[0050] Optionally, in step d), the hot rolling temperature of the alloy can be independently selected from any value of 1200°C, 1210°C, 1220°C, 1230°C, 1240°C, 1250°C, 1260°C, 1270°C, 1280°C, 1290°C, 1300°C, or any range between two thereof; the rolling reduction can be independently selected from any value of 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, or any range between two thereof, and a preliminary rolled plate is obtained after cooling;

[0051] Preferably, the alloy ingot is hot rolled at 1250° C. with a rolling reduction of 28%, and then cooled to obtain a preliminary rolled plate.

[0052] Optionally, in step e), the preliminary rolled plate is cold rolled at room temperature, the cold rolling temperature of the alloy can be independently selected from any value of 15°C, 16°C, 17°C, 18°C, 19°C, 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, or any range between two values; the rolling reduction can be independently selected from any value of 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, or any range between two values, to obtain a final rolled plate;

[0053] Preferably, the alloy ingot is cold rolled at room temperature 20°C with a rolling reduction of 90% to obtain a preliminary rolled plate.

[0054] Optionally, in step f), the annealing heat treatment temperature of the alloy can be independently selected from any value of 1100°C, 1110°C, 1120°C, 1130°C, 1140°C, 1150°C, 1160°C, 1170°C, 1180°C, 1190°C, 1200°C, 1210°C, 1220°C, 1230°C, 1240°C, 1250°C, 1260°C, 1270°C, 1280°C, 1290°C, 1300°C, or any range between two thereof; the heat treatment time can be independently selected from 10 min, 11 min, 12 min, 13 min, 14 min, 15 min, 16 min, 17 min, 18 min, 19 min, 20 min, 21 min, 22 min, 23 min, 24 min, 25 min, 26 min, 27 min, 28 min, 29 min, 30 min, 31 min, 32 min, 33 min, 34 min, 35 min, 36 min, 37 min, 38 min, 39 min, 40 min, 41 min, 42 min, 43 min, 44 min, 45 min, 46 min, 47 min, 48 min, 49 min, 50 min, 51 min, 52 min, 53 min, 54 min, 55 min, 56 min, 57 min, 58 min, 59 min, 60 min, 61 min, 62 min, 63 min, 64 min, 65 min, 66 min, 67 min, 68 min, 69 min, min, 26 min, 27 min, 28 min, 29 min, 30 min, or any range between them;

[0055] Preferably, the final rolled plate is annealed at 1100°C for 10 min and water quenched to obtain a preliminary heat-treated plate;

[0056] Optionally, in step g), the cryogenic treatment temperature of the alloy can be independently selected from -196 ° C and an appropriate floating temperature; the heat treatment time is independently selected from any value among 0 h, 1 h, 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h, 11 h, 12 h, 13 h, 14 h, 15 h, 16 h, 17 h, 18 h, 19 h, 20 h, 21 h, 22 h, 23 h, 24 h, 25 h, 26 h, 27 h, 28 h, 29 h, 30 h, 31 h, 32 h, 33 h, 34 h, 35 h, 36 h, 37 h, 38 h, 39 h, 40 h, 41 h, 42 h, 43 h, 44 h, 45 h, 46 h, 47 h, 48 h, or any range between two of them;

[0057] Preferably, the primary heat-treated plate is subjected to -196°C liquid nitrogen cryogenic treatment for 24 hours, and then taken out and restored to room temperature to obtain a secondary heat-treated plate;

[0058] Optionally, in step h), the aging heat treatment temperature of the alloy can be independently selected from any value of 600°C, 605°C, 610°C, 620°C, 630°C, 640°C, 650°C, 660°C, 670°C, 680°C, 690°C, 700°C, 710°C, 720°C, 730°C, 740°C, 750°C, 760°C, 770°C, 780°C, 790°C, 800°C, or any range between two thereof; the heat treatment time is independently selected from 120 min, 130 min, 140 min, 150 min, 160 min, 170 min, 180 min, 190 min, 200 min, 210 min, 220 min, 230 min, 240 min, 200 min, 300 min, 400 min, 500 min, 600 min, 700 min, 800 min, 900 min, 1000 min, 1100 min, 1200 min, 1300 min, 1400 min, 1500 min, 1600 min, 1700 min, 1800 min, 1900 min, 2000 min, 2100 min, 2200 min, 2300 min, 2400 min, 2000 min, 3 ... min, 400 min, 480 min, or any range between them;

[0059] Preferably, the secondary heat-treated plate is subjected to aging heat treatment at 600° C. for 2 h and water quenched to obtain a final plate.

[0060] Beneficial effects:

[0061] 1) A wide temperature range multi-principal component alloy disclosed in the present invention has a yield strength of 900-1200 MPa, a tensile strength of 1500-1900 MPa, and an elongation at break of more than 15% at room temperature; the yield strength of the wide temperature range multi-principal component alloy at 600°C is 600-900 MPa, the tensile strength is 900-1200 MPa, and the elongation at break is more than 25%; the yield strength of the wide temperature range multi-principal component alloy at 800°C is 400-700 MPa, the tensile strength is 400-700 MPa, and the elongation at break is more than 25%.

[0062] 2) The preparation method according to the present invention has strong plastic processing ability and strong antioxidant ability, and has low requirements for preparation conditions of traditional steel materials; there are no particularly precise parameter requirements for smelting and heat treatment; the cooling rate requirement for the alloy is low, and it is suitable for industrial mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Figure 1 The XRD spectrum of the multi-principal alloy of Example 1 of the present invention;

[0064] Figure 2 This is a SEM microscopic morphology photograph of the multi-principal alloy of Example 1 of the present invention;

[0065] Figure 3 is the tensile curve of the multi-principal alloy of Example 1 of the present invention;

[0066] Figure 4 EBSD image of the multi-principal element alloy of Example 1 of the present invention;

[0067] Figure 5 This is the nanoindentation map of the multi-principal component alloy of Example 1 of the present invention. DETAILED DESCRIPTION

[0068] As mentioned above, the present invention relates to the composition design and preparation of a novel wide temperature range high-strength and tough multi-principal component alloy. The present invention is aimed at extreme load application environments that require excellent mechanical properties within a wide temperature range. Starting from the composition design of the development of a novel multi-principal component alloy, the influence of various alloying elements on thermodynamic parameters such as configuration entropy and mixing enthalpy is considered, thereby constructing a heterogeneous microstructure composed of intermetallic compounds with a low stacking fault energy FCC phase matrix and a small amount of superlattice structure. In addition, the alloy described in the present invention has good plastic processing ability and antioxidant ability, and the smelting and rolling processes used are relatively simple and easy to operate. The alloying elements used in the present invention are all common metal and non-metal elements, and the raw materials are easy to obtain. All of the above can greatly reduce the manufacturing cost and processing conditions of the alloy, which is helpful to promote the specific application of the alloy.

[0069] Provided is a wide temperature range high strength and toughness multi-principal alloy, the composition of the wide temperature range high strength and toughness multi-principal alloy satisfies the general formula Fe a Ni b Co c Al d Ta e M f , wherein M is selected from at least one of Si, B, P, and C. A series of preparation process details such as alloy melting, rolling, and heat treatment of the multi-principal component alloy are provided, and finally a multi-principal component alloy with excellent performance in a wide temperature range is obtained. The new wide temperature range high-strength and tough multi-principal component alloy of the present invention has excellent mechanical properties in a wide temperature range, and has the advantages of simple preparation process and low cost. It has good application potential in extremely harsh service scenarios and can be used in structural materials in the fields of aerospace, advanced weapons manufacturing, etc.

[0070] Among the numerous multi-principal alloy systems, FeNiCo-based multi-principal alloys have attracted widespread attention in the academic community due to their excellent wide temperature range strength-plasticity matching and superelasticity. The matrix of the FeNiCo-based alloy is a face-centered cubic structure with low stacking fault energy, so it has excellent low-temperature plastic deformation ability. In addition, the FeNiCo matrix has a large solid solubility with many transition metals, and alloying can be fully utilized to improve the comprehensive mechanical properties and functional characteristics of the material. By studying and comparing non-equiatomic ratio FeNiCo matrix alloys, the present invention selects 35≤Fe≤45, 25≤Ni≤35, and 15≤Co≤25 as the matrix alloy ratio. Adding a certain amount of Al element to the alloy can make some atoms inside the alloy form a BCC solid solution structure or a B2 phase superlattice structure. Al elements with large atomic radius can bring sufficient lattice distortion effect. In order to precipitate a small amount of NiAl phase and Ni3Al phase from the solid solution, the atomic percentage of Al element designed in the present invention is 7≤Al≤15. On the other hand, studies have shown that the addition of a small amount of Ta can improve the strength and plasticity of FCC-based multi-principal alloys, but it is generally not advisable to be too high. At the same time, the introduction of different contents of Al, Ta and other γ' phase forming elements helps to improve the precipitation of strengthening phases. The atomic percentage of Ta in the present invention is designed to be 0 <Ta≤5。

[0071] And for non-metallic element B, it is often used as a grain boundary strengthening element. A small amount of C is often used in solid solution strengthening elements and fine grain strengthening elements in alloys. A large amount of C is easily combined with strong carbide forming elements to form hard and brittle carbides, which will deteriorate toughness. Si exists in ferrite or austenite in the form of solid solution, which can reduce the austenite phase region, significantly improve the elastic limit, yield strength and yield strength ratio of steel, and improve fatigue strength. But excessive Si can significantly reduce the plasticity and toughness of the alloy, and the total added content is as much as possible less than 2%. P has strong solid solution strengthening and cold work hardening effects in steel, and is often added to alloys as an alloying element to improve its strength and the oxidation resistance of the alloy, but it should be noted that too much P reduces its plastic processing performance. In summary, the total amount of non-metallic elements added in the present invention is between 0-2.

[0072] The present invention will be further described below in conjunction with the examples. It should be understood that these examples are only used to illustrate the present invention, but not to limit the scope of the present invention.

[0073] The present invention provides the following specific embodiments and all possible combinations thereof. For the purpose of brevity, the present invention does not record the various specific combinations of these embodiments one by one, but it should be considered that the present invention specifically records and discloses all possible combinations of these embodiments.

[0074] The experimental methods in the following examples without specifying specific conditions are usually carried out according to conventional conditions or conditions recommended by the manufacturer.

[0075] Unless otherwise specified, the raw materials used in the examples of the present invention and the materials used in the tests were purchased from commercial sources.

[0076] The analytical measuring instruments used in the embodiments of the present invention are as follows:

[0077] The alloy sample surface was ground using Trulli VP-430 and Hitachi ion mill standard model IM4000Ⅱ to prepare samples for microstructure observation and characterization.

[0078] The XRD test of the alloys was carried out using a Bruker D8 Advance X-ray diffractometer.

[0079] A ZEISS EVO 18 scanning electron microscope was used to characterize the microstructure of the multi-principal alloy samples.

[0080] Electron backscatter diffraction (EBSD) analysis of the alloy samples was carried out using an Apreo S LoVac thermal field emission scanning electron microscope.

[0081] The multi-principal alloy dog-bone tensile specimens were prepared using Taiwan Qinghong G43S immersion slow-wire electric spark wire cutting machine.

[0082] The room temperature mechanical properties of the alloys were measured using an AGS-X 10KN mechanical testing machine and a RVX-112B video extensometer.

[0083] An Instron 45582 dual-column electronic universal testing machine was used to measure the high temperature mechanical properties of the alloys.

[0084] Example 1

[0085] The composition expression of the target alloy plate is as follows: Fe 40.76 Ni 28.2 Co 17 Al 11 Ta 2.5 C 0.5 B 0.04 (at.%). The process of preparing the multi-principal alloy is carried out according to the following steps:

[0086] 1) Proportion of raw materials: According to the composition in the above expression, weigh the alloy raw materials of Fe, Ni, Co, Al, Ta, C and B with a purity greater than 99.9% for batching;

[0087] 2) Preparing a master alloy ingot: placing the alloy raw material obtained in step 1) in a smelting device and smelting it under the protection of an argon atmosphere; melting it at 1500°C and keeping it warm for 10 minutes, then pouring the molten alloy into a cooling mold and cooling it for 30 minutes, thereby obtaining a master alloy ingot with uniform composition;

[0088] 3) Homogenization heat treatment: the multi-principal alloy cast ingot prepared in step 2) is subjected to homogenization heat treatment at 1300°C for 3 h, and water quenched to obtain an alloy ingot with uniform structure;

[0089] 4) Hot rolling treatment: hot rolling the multi-principal alloy ingot obtained in step 3) at 1250°C with a rolling reduction of 30%, and cooling to obtain a preliminary rolled plate;

[0090] 5) Cold rolling treatment: cold rolling the multi-principal alloy preliminary rolled plate obtained in step 4) at room temperature with a rolling reduction of 90% to obtain a final rolled plate;

[0091] 6) Annealing treatment: the final rolled plate obtained in step 5) is subjected to annealing heat treatment at 1100°C for 10 min, and water quenched to obtain a preliminary heat-treated plate;

[0092] 7) Cryogenic treatment: The primary heat-treated plate obtained in step 6) is subjected to cryogenic treatment in liquid nitrogen at -196 °C for 24 h, and then taken out and the temperature is restored to room temperature to obtain a secondary heat-treated plate:

[0093] 8) Aging treatment: The secondary heat-treated plate obtained in step 7) is subjected to aging heat treatment at 600 °C for 2 h, followed by water quenching to obtain the final plate.

[0094] The multi-principal alloy obtained according to the above steps was tested and characterized, and the results are described as follows in conjunction with the accompanying drawings.

[0095] Figure 1 The XRD spectrum of the multi-principal alloy prepared in Example 1 is shown. Figure 1 It can be seen that when the atomic arrangement in the crystal phase is long-range orderly, several sharp diffraction peaks will appear in the XRD spectrum, corresponding to different crystal plane diffraction. The physical phase can be determined by observing the diffraction peaks of the XRD spectrum and comparing the PDF card.

[0096] Figure 2 The SEM microscopic morphology of the multi-principal alloy prepared in Example 1 is shown. Figure 2 It can be seen that the segregation of the alloy is improved after heat treatment, and dispersed carbides can be seen on the final sample.

[0097] Figure 3 FIG. 2 shows the tensile curve of the multi-principal alloy prepared in Example 1. Figure 3 It can be seen that the yield strength of the alloy is as high as 1100 MPa, the tensile strength is as high as over 1800 MPa, and the elongation at break is over 20%.

[0098] Figure 4 The image of the alloy prepared in Example 1 after mechanical polishing and ion polishing observed under EBSD is shown. Figure 4 The grain size, grain boundary distribution, etc. can be clearly observed.

[0099] Figure 5 The hardness distribution of the alloy prepared in Example 1 is shown. It can be found that the hardness is different at different positions and there are different soft and hard structures.

[0100] Example 2-25

[0101] According to the target alloy composition expression listed in Table 1, the corresponding raw materials are weighed and mixed. The rest of the preparation and testing process is the same as that of Example 1.

[0102] The yield strength, tensile strength, elongation at break and other data of the multi-principal component alloys prepared in Examples 2-25 are listed in Table 1 below.

[0103] Comparative Examples 1 and 2

[0104] FeNiCoTiAl-based multi-principal alloy from patent application CN201410466857.2, which also contains a small amount of Si, Mn, C, P, S and other elements. W / Mo elements are added to the Fe-Ni-Co alloy to improve the strength through solid solution strengthening; at the same time, appropriate amounts of Ti and Al are added to precipitate the dispersion strengthening phase (γ′) during the aging process, further improving the comprehensive performance of the alloy. After optimizing the alloy composition, the alloy strip is smelted-forged-hot rolled-cold rolled and heat treated to have high strength, high service temperature and low elastic modulus temperature coefficient in a wide temperature range (-60 °C to 400 °C). The tensile strength of the alloy at room temperature is greater than 1500 MPa, and the elongation at break is greater than 3%; at 400 °C, the tensile strength is greater than 1450 MPa, and the elongation at break is greater than 2.5%; at 450 °C, the tensile strength is greater than 1350 MPa, and the elongation at break is greater than 2.5%. The alloy material has good strength and toughness and has the potential for use at high temperatures.

[0105] Comparative Examples 3 and 4

[0106] The patent application with publication number CN202410354165.2 discloses a high damping TiZr-based high entropy alloy with high strength and plasticity over a wide temperature range and a preparation method thereof, which is expected to become a damping structural material with integrated structural functions used in high-temperature service environments. The room temperature tensile yield strength of the high damping TiZr-based high entropy alloy described in the alloy at room temperature is >850 MPa, the tensile strength is >900 MPa, and the tensile plasticity is >10%.

[0107] Among them, comparative example 3 is the Zr 43.77 Hf 21.89 Ti 16.42 Nb 16.42 O 1.5 Alloy. After homogenization treatment, it is taken out and water-cooled, and then multiple cold rolling is performed, with a total deformation of 92%. After the plate is obtained, it is kept at 980 ° C for 0.75h for solution treatment, and then taken out and water-cooled. The organization is a uniform BCC equiaxed crystal matrix organization, and a small amount of ω phase precipitates on the BCC matrix; its room temperature tensile yield strength can reach 895 MPa, the tensile strength can reach 905 MPa, and the tensile plasticity is 10.6%. Comparative Example 4 is the invention Zr 43.64 Hf 21.82 Ti 16.37 Nb 16.37 O 1.8The alloy was homogenized, water-cooled, and then cold-rolled for multiple passes with a total deformation of 90%. The plate was then solution-treated at 950 °C for 0.5 h and water-cooled. Characterization revealed that a small amount of ω and α′′ phases precipitated on the matrix; its room temperature tensile yield strength was 996 MPa, tensile strength was 997 MPa, and tensile plasticity was 15.1%.

[0108] Comparative Example 5

[0109] From the document "Acta Materialia 2024 Volume 268, 119770", a NiFeCoCr-based multi-principal alloy is introduced into the non-equiatomic NiFeCoCr matrix at room temperature by introducing a high content of Ti, Al, Ta, W, Nb and other L12 forming elements, which promotes the precipitation of a large number of multi-component L12 nanoparticles coherent with the FCC matrix. The L12 density is as high as 58.5%, and the solid solution temperature is about 1165 °C. This ensures that the alloy can maintain high strength from low temperature to high temperature. On the other hand, by reasonably controlling the addition of Co elements, stabilizing the nanoparticles and reducing the stacking fault energy of the alloy, a large number of stacking faults are stimulated during low temperature deformation, thereby improving its strength and plasticity at low temperature. The alloy shows good strength-toughness matching at 25°C. The yield strength can reach 760 MPa, the tensile strength can reach 1230 MPa, and the elongation at break is 34%. In addition, the alloy exhibits obvious abnormal yield phenomenon at 700 °C, and the yield strength can reach 1045 MPa, which is mainly attributed to the Kear-Wilsdorf (KW) lock formed by the cross-slip phenomenon of superlattice dislocations inside L12. More importantly, the grain boundaries are serrated by mechanical heat treatment, thereby improving the ability of the grain boundaries to resist medium-temperature brittleness. Even under higher stress, the alloy still exhibits excellent ductility in the medium temperature range of 600-800 °C. Most traditional nickel-based or cobalt-based high-temperature alloys show very serious intergranular brittleness in this temperature range, resulting in premature brittle fracture along the grain boundaries.

[0110] The yield strength, tensile strength and elongation at break of the alloys prepared in Comparative Examples 1-5 are listed in Table 1 below.

[0111] Table 1 Yield strength, tensile strength and elongation at break of the alloys of Examples 1-25 and Comparative Examples 1-5 and their main heat treatment schemes at different test temperatures

[0112]

[0113]

[0114]

[0115]

[0116]

[0117]

[0118] In summary, the new multi-principal alloy according to the present invention has good strength-toughness matching in a wide temperature range and can meet the application requirements in extremely harsh service scenarios. The present invention is of great significance for the expansion of the types of metal structural materials used in extreme load application environments and the application research of multi-principal alloys.

[0119] The above descriptions are only several embodiments of the present invention, and are not intended to limit the present invention in any form. Although the present invention is disclosed as above with preferred embodiments, these embodiments are not intended to limit the present invention. Any technician familiar with the profession, without departing from the scope of the technical solution of the present invention, using the technical content disclosed above to make some changes or modifications are equivalent to equivalent implementation cases, and all belong to the scope of the technical solution of the present invention.

Claims

1. A high-strength and high-toughness multi-principal alloy with a wide temperature range, characterized in that: The general formula of the multi-principal alloy is Fe a Ni b Co c Al d Ta e M f , wherein M is selected from at least one of Si, B, P, and C; a represents the atomic percentage of the alloy element Fe, b represents the atomic percentage of the alloy element Ni, c represents the atomic percentage of the alloy element Co, d represents the atomic percentage of the alloy element Al, e represents the atomic percentage of the alloy element Ta, and f represents the atomic percentage of the alloy element M, wherein 35≤a≤45, 25≤b≤35, 15≤c≤25, 7≤d≤15, 0 <e≤5,0<f≤2,78≤a+b+c≤85,0<e+f≤5,a+b+c+d+e+f =100。 2. The wide temperature range high strength and toughness multi-principal alloy according to claim 1, characterized in that: In the general formula, 38 ≤ a ≤ 42, 27 ≤ b ≤ 31, 15 ≤ c ≤ 18, 9 ≤ d ≤ 12, 2 < e ≤ 3, 0 < f ≤ 1, and M is B and C.

3. A method for preparing a high-strength and high-toughness multi-principal alloy in a wide temperature range, characterized in that: Including: a) According to the general formula Fe a Ni b Co c Al d Ta e M f Weighing alloy raw materials including Fe, Ni, Co, Al, Ta and M for batching; b) Melting the alloy raw materials, including melting under an inert atmosphere, holding the temperature, and cooling to obtain an alloy ingot; c) Subjecting the alloy ingot to homogenization heat treatment at 1300 - 1400 °C for 3 - 12 h and then performing water quenching to obtain an alloy ingot with a uniform structure.

4. The method for preparing a wide temperature range high strength and toughness multi-principal component alloy according to claim 3, characterized in that: In step b), the melting temperature is 1400 - 1700 °C; the holding time is at least 10 min, and the cooling time is 10 - 30 min; in step c), the homogenization heat treatment temperature is 1300 - 1400 °C, the duration is 3 - 12 h, and water quenching is performed; the melting is induction melting, including: placing the alloy raw materials in an induction melting furnace, evacuating and then filling with an inert gas to 0.05 - 0.1 MPa, melting and holding at 1500 - 1600 °C for 15 - 20 min, and then transferring to a mold for cooling for 20 - 30 min; the homogenization heat treatment temperature is 1300 - 1400 °C, the duration is 3 - 6 h, and water quenching is performed.

5. A multi-principal alloy plate, characterized in that: The multi - principal - element alloy sheet is obtained by the following method from the multi - principal - element alloy described in claim 3 or 4, including: d) Hot - rolling the alloy ingot at 1200 - 1300 °C with a rolling reduction of 20 - 30 %, and cooling to obtain a preliminarily rolled sheet; e) Cold - rolling the preliminarily rolled sheet described in step d) at room temperature with a rolling reduction of 80 - 90 % to obtain a finally rolled sheet; f) Annealing heat - treating the finally rolled sheet described in step e) at 1100 - 1300 °C for 10 - 30 min and then performing water quenching to obtain a preliminarily heat - treated sheet; g) Subjecting the preliminarily heat - treated sheet described in step f) to cryogenic treatment with liquid nitrogen at - 196 °C for 0 - 48 h, taking it out and restoring the temperature to room temperature to obtain a secondary heat - treated sheet; h) Aging heat - treating the secondary heat - treated sheet described in step g) at 600 - 800 °C for 2 - 8 h and then performing water quenching to obtain the final sheet.

6. The multi-principal alloy plate material according to claim 5, characterized in that: In step d), the hot - rolling is carried out under an inert atmosphere or with cladding protection to prevent oxidation; the hot - rolling temperature is above 1250 °C, the single - pass rolling reduction is 2 - 3 %, the number of rolling passes is more than 10, and the total rolling reduction is 25 - 30 %.

7. The multi-principal alloy plate material according to claim 5, characterized in that: In step e), the cold - rolling temperature is 15 - 30 °C, the single - pass rolling reduction is 5 - 10 %, the number of rolling passes is more than 10, and the total rolling reduction is 80 - 90 %; the cooling rate after hot - rolling is greater than 20 °C / min.

8. The multi-principal alloy plate material according to claim 5, characterized in that: In step f), the annealing includes: placing the final rolled plate in a heat treatment furnace heated to 1100-1300°C for annealing heat treatment, water quenching, and obtaining a preliminary heat-treated plate; the annealing is carried out under an inert atmosphere, or sheathed to prevent oxidation; the annealing temperature is 1100-1200°C; the annealing time is 10-20 min, and the cooling rate of the water quenching after the annealing is greater than 300°C / s.

9. The multi-principal alloy plate material according to claim 5, characterized in that: In step g), the deep cooling includes: subjecting the final rolled plate to a -196°C deep cooling treatment; the deep cooling treatment should be sealed and stored in liquid nitrogen; the temperature of the deep cooling treatment is -196°C; and the duration of the deep cooling treatment is 24 hours.

10. The multi-principal alloy plate material according to claim 5, characterized in that: In step h), the annealing includes: placing the final rolled plate in a heat treatment furnace heated to 600-800°C for aging heat treatment, water quenching, and obtaining a preliminary heat-treated plate; the aging is carried out under an inert atmosphere, or sheathed to prevent oxidation; the aging temperature is 600°C; the aging time is 2 hours; the cooling rate of the water quenching after aging is greater than 300°C / s.

Images