A nickel-based alloy with coexistence of nanotwins and precipitates and a preparation method thereof

Abstract

The present application relates to the field of metal structural materials, in particular to a nickel-based alloy with coexistence of nano-twin and precipitate and a preparation method thereof.The microstructure of the nickel-based alloy is a structure with coexistence of nano-twin and precipitate; wherein the nano-twin is distributed in at least 60% or more of the grain interiors; the precipitate is distributed in the nickel-based alloy with a volume fraction of more than 30%. The nickel-based alloy with coexistence of nano-twin and precipitate provided by the present application effectively alleviates the problem that the strength and plasticity of the material are contrary to each other, and obtains excellent ductility while obtaining ultrahigh strength. In addition, the short-time aging process effectively shortens the aging period of the traditional nickel-based alloy in the preparation process, significantly improves the work efficiency, and saves the cost. The nickel alloy prepared by the method obtains the combination of strength and ductility which is difficult to achieve in the past, and compared with the traditional heat treatment process, the work efficiency is improved by more than 50%, which can be widely applied in the field of structural materials.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of metal structural materials, and particularly relates to a nickel-based alloy with coexisting nano-twin and precipitate and a preparation method thereof. BACKGROUND

[0002] Nickel-based alloys have excellent mechanical properties at room temperature and high temperature, and are the preferred materials for structural components in the aviation industry and chemical processing. The performance of nickel-based alloys is largely dependent on the size and spatial distribution of precipitates. Generally, the high strength of nickel-based alloys comes from precipitates with a size of tens to hundreds of nanometers. However, these precipitates usually severely sacrifice ductility to improve strength. Properly regulating the type, size, shape, volume fraction and distribution of precipitates is crucial for developing alloys with high strength while maintaining sufficient ductility, and is one of the ways to effectively improve the comprehensive performance.

[0003] The introduction of twins has been proven to be an effective method to solve the contradiction between strength and elongation in recent years, because the unique ability of twins to hinder and transmit dislocations can provide compatibility between material strength and ductility. By pulse electrolytic deposition technology, high-density twins were prepared in pure copper, and amazing performance of 1068 MPa tensile strength and 13.5% elongation was obtained. Therefore, compared with traditional grain refinement, the introduction of twins can give the material extremely excellent comprehensive performance.

[0004] However, it is very difficult to introduce high-density twins into metal materials. At present, the most effective way is electrolytic deposition and magnetron sputtering deposition technology, but it is difficult to prepare large-size samples by these two methods. In addition, how to introduce precipitates while ensuring twins is a problem to be solved at present, because current studies have shown that the two structures are difficult to coexist (scripta materialia. 2021, 192, 83-88).

[0005] Therefore, how to effectively introduce high-density twin structure into nickel-based alloys, and regulate the precipitate structure while ensuring the twin, and finally obtain nickel-based alloys with ultra-high performance, is a problem to be solved by those skilled in the art. SUMMARY

[0006] In view of the above defects or improvement needs of the prior art, the present application aims to provide a nickel-based alloy with coexistence of nanotwins and precipitates and a preparation method thereof. The nickel-based alloy has a microstructure of coexistence of nanotwins and precipitates; the nanotwins are distributed in at least 60% of the grains; and the precipitates are distributed in the nickel-based alloy with a volume fraction of more than 30%. The nickel-based alloy with coexistence of nanotwins and precipitates provided by the present application effectively alleviates the problem of conflict between strength and plasticity of the material itself, and obtains excellent ductility while obtaining ultra-high strength.

[0007] To achieve the above-mentioned purpose, according to a first aspect of the present application, a nickel-based alloy with coexistence of nanotwins and precipitates is provided, and the microstructure is a structure of coexistence of nanotwins and precipitates.

[0008] The nanotwins are distributed in at least 60% of the grains; and the precipitates are distributed in the nickel-based alloy with a volume fraction of more than 30%.

[0009] As a preferred embodiment of the present application, the width of the nanotwins is 5nm-30nm, and the size of the twin network formed by the nanotwins is 15nm-800nm.

[0010] The misfit degree between the precipitates and the nickel matrix is less than 0.3%, and the size is 5nm-10nm.

[0011] As a preferred embodiment of the present application, the orientation and integrity of the grains with the nanotwins distributed therein remain unchanged before and after the formation of the nanotwins.

[0012] As a preferred embodiment of the present application, the elements of the nickel-based alloy include Ni, Cr, Al, Ti, Nb and Mo.

[0013] The composition of the nickel-based alloy is measured by element mass percentage as follows: Cr:(8-20)%, Al:(1.3-3.6)%, Ti:(2.4-5.4)%, Nb:(1.1-3.2)%, Mo:(2.5-5.8)%, and the balance is Ni.

[0014] As a preferred embodiment of the present application, the elements of the nickel-based alloy include Ni, Cr, Al, Ti, Nb, Mo, Fe, Mn, Si, Zr, C and Cu.

[0015] The composition of the nickel-based alloy is measured by element mass percentage as follows: Cr:14.5%, Al:1.7%, Ti:2.6%, Nb:2.1%, Mo:3.0%, Fe:0.1%, Zr:0.04%, Mn:0.03%, Si:0.03%, C:0.05%, Cu:0.02%, and the balance is Ni.

[0016] According to another aspect of the present application, there is provided a method for preparing the nickel-based alloy with coexistence of nanotwin and precipitate according to any one of the first aspect of the present application, characterized in that it comprises the following steps:

[0017] (1) subjecting a plate-shaped or block-shaped nickel-based alloy blank to be treated to solid solution treatment and obtaining a single-phase nickel-based alloy with uniform structure by water quenching;

[0018] (2) subjecting the single-phase nickel-based alloy to plastic deformation in three dimensions in turn at -100°C or below;

[0019] (3) performing heat treatment after the step (2) and obtaining a nickel-based alloy with coexistence of nanotwin and precipitate after cooling.

[0020] As preferred in the present application, in the step (1);

[0021] The solid solution treatment is performed at 1120°C for 1.5-2h.

[0022] As preferred in the present application, in the step (2);

[0023] The speed of plastic deformation is 15m / s±5m / s; the deformation amount in three dimensions is respectively accumulated to 0.4-0.45; wherein the deformation amount is the ratio of the initial height to the final height after deformation.

[0024] As preferred in the present application, in the step (3);

[0025] The heat treatment is performed at 650-850°C for 60-120min under inert gas protection.

[0026] Overall, compared with the prior art, the above technical solutions conceived by the present application mainly have the following technical advantages:

[0027] (1) The nickel-based alloy provided by the present application obtains multi-scale and hierarchical cross-twin in the grain interior; and the introduction of twin does not destroy the orientation and boundary of the initial grain, which more effectively divides the material into different structures, such as grains with twin and grains without twin, which more effectively ensures the strength and ductility of the material. Further, under the premise of ensuring the twin density, the L12-Ni3(Al,Ti) precipitate coexists with the twin, and the precipitate density does not decrease due to the presence of the twin. Excellent material strength and ductility are more suitable for working in extremely harsh aerospace and deep sea environments.

[0028] (2) In the present application, the preparation of the nickel-based alloy with coexisting nano-twin and precipitate is obtained by high-temperature vacuum smelting and vacuum consumable smelting, so that the required pure material is obtained to the maximum extent; and the multi-scale and hierarchical cross-twin is obtained in the grain by a unique process; in addition, under the premise of ensuring the twin density, the heat treatment process is optimized, so that the L12-Ni3(Al, Ti) precipitate coexists with the twin, and the precipitate density does not decrease due to the presence of the twin. It is determined that the tensile strength of the multi-scale hierarchical twin nickel-based alloy prepared in the present application at room temperature is more than 1600 MPa, the yield strength is more than 1150 MPa, the elongation is more than 28%, the tensile strength at high temperature (700 DEG C) is more than 1200, the elongation is more than 15%, the comprehensive performance is excellent, and the application prospect is good.

[0029] (3) In the present application, in the preparation method of the nickel-based alloy with coexisting nano-twin and precipitate, the multi-scale and hierarchical nano-twin is successfully introduced into the nickel-based alloy by using the low-temperature high-speed forging method with sequence, quantification and different directions, the twin grid size formed by the mutual cross-twin is 15 nm to 800 nm, and the thickness of the twin itself also shows a progressive effect, so that the matrix is refined and the material strength is improved; in addition, the unique dislocation passing ability of the twin also gives the material excellent ductility.

[0030] The nickel-based alloy prepared in the present application has the advantages of convenient twin introduction process, remarkable effect and low cost requirement; and the introduction of the twin effectively changes the spatial structure of the material, which proves that the introduction of the twin by the process is not a coincidence.

[0031] (4) In the present application, in the preparation method of the nickel-based alloy with coexisting nano-twin and precipitate, the precipitate introduced by the heat treatment process needs shorter time compared with the traditional nickel-based alloy (more than 10 hours), so that the process cycle is shortened and the cost is greatly saved. In addition, the density of the precipitate does not decrease due to the short-period heat treatment process.

[0032] (5) In the present application, due to the advantages of the short-time heat treatment process, the obtained precipitate has lower lattice mismatch degree with the matrix, which maximally reduces the accumulation of elastic strain caused by dislocation shear, thereby preventing the crack initiation at the interface and having good ductility; at the same time, the twin and the precipitate are successfully combined, and the presence of the precipitate does not sacrifice the density of the twin.

[0033] (6) In the present application, in the preparation method of the nickel-based alloy with coexisting nano-twin and precipitate phase, the solid solution treatment temperature is very important, when the solid solution treatment temperature is 1120℃, the grain of the nickel-based alloy will present a heterogeneous structure, the appearance of this structure greatly improves the material performance, and also has a great influence on the introduction of twin. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 Preparation process of the nickel-based alloy with coexisting nano-twin and precipitate phase for the embodiment example of the present application;

[0035] Figure 2 Schematic diagram of sequentially performing plastic deformation in three-dimensional direction of single-phase nickel-based alloy for the embodiment example of the present application;

[0036] Figure 3 Microstructure morphology diagram of the nickel-based alloy with coexisting nano-twin and precipitate phase for the embodiment 1 example of the present application; wherein Figure 3 a in the above is the metallographic picture of the nickel-based alloy of embodiment 1, Figure 3 b in the above is the transmission electron microscope diagram of the nickel-based alloy of embodiment 1;

[0037] Figure 4 Microstructure morphology diagram of the nickel-based alloy with coexisting nano-twin and precipitate phase for the embodiment 2 example of the present application; wherein Figure 4 a in the above is the metallographic picture of the nickel-based alloy of embodiment 2, Figure 4 b in the above is the transmission electron microscope diagram of the nickel-based alloy of embodiment 2, Figure 4 c in the above is the electron dispersion spectrum (EDS) diagram of the precipitate of the nickel-based alloy of embodiment 2. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application. In addition, the technical features involved in each embodiment of the present application described below can be combined with each other as long as they do not conflict with each other.

[0039] The present application provides a preparation method of a nickel-based alloy with coexisting nano-twin and precipitate phase, comprising the following steps:

[0040] Step one, solid solution treatment:

[0041] The plate or block nickel-based alloy blank to be treated is subjected to a solution treatment at 1120 °C for 1.5-2 h in an inert gas protection environment, and then water quenched to obtain a single-phase nickel-based alloy with uniform structure and without a large amount of carbide precipitation. The plate or block nickel-based alloy to be treated is an existing nickel-based alloy or a nickel-based alloy prepared by an existing method.

[0042] Step two, multi-scale hierarchical twin preparation:

[0043] The blank after the solution treatment in step four is subjected to plastic deformation in three dimensions below -100 °C in a cycle to a preset deformation amount, as shown in the following formula: Figure 1 The deformation speed is ensured to be about 15 m / s, and the floating range is 5 m / s. The preset deformation amount ε of the three directions is finally 0.4-0.45, wherein ε = ln (L0 / L f ), L0 is the initial height of the nickel-based alloy blank, and L f is the final height of the nickel-based alloy blank after deformation. This process can obtain the multi-scale hierarchical twin grid in the grain interior as described above.

[0044] The plastic deformation in three dimensions in a cycle refers to plastic deformation in three directions of the material, and the deformation sequence is strictly in the order of x-y-z-x-y-z….

[0045] Step three, heat treatment preparation

[0046] The blank after the twin preparation in step five is subjected to a heat treatment in a heating furnace at a temperature of 650-850 °C for 60-120 min under inert gas protection, and then the sample is cooled at room temperature to obtain a sample with a nano-scale precipitate and a multi-scale hierarchical twin in the interior.

[0047] In some embodiments, the preparation of the nickel-based alloy rod blank to be treated in step one is prepared by element selection according to the components and component proportions of the nickel-based alloy, nickel-based alloy smelting, and free forging. Specifically as follows:

[0048] Nickel-based alloy smelting:

[0049] According to the above mass percentage, each element metal is selected and mixed and placed in a vacuum induction melting furnace. After the vacuum degree is extracted to less than 10 Pa, the power heating can be started. When the vacuum degree continues to be extracted to 1.0-0.5 Pa, the protective gas argon is filled into the furnace. The smelted material is annealed, and after the oxide skin is removed, it is subjected to vacuum consumable furnace smelting. The vacuum process is consistent with the above. Finally, the smelted material ingot is obtained for use.

[0050] Free forging:

[0051] The nickel-based alloy ingot prepared by melting is heated to 1000-1150 DEG C and is kept for 2-3 hours under inert gas, and then is hot forged into a rod blank.

[0052] In some embodiments, in the melting step of the nickel-based alloy, the vacuum degree in the vacuum induction melting furnace is extracted to less than 10 Pa after the charging is completed, and then the power is turned on for heating. When the vacuum degree reaches 1.0-0.5 Pa, the protective gas argon is filled into the furnace. The vacuum degree of the vacuum consumable melting furnace is basically the same as that of the vacuum induction melting furnace.

[0053] In some embodiments, after the rod blank of the nickel-based alloy is prepared, it is subjected to mechanical processing, specifically: the prepared rod blank alloy is mechanically processed into a long rectangular plate or block blank, so as to facilitate the subsequent twin crystal introduction. The long rectangular blank obtained by mechanical processing is processed with the center of the round rod as the symmetry axis.

[0054] In some embodiments, in the melting step, the free forging step and the solid solution treatment step of the nickel-based alloy, the atmosphere is inert gas, for example, argon.

[0055] In some embodiments, in the solid solution treatment step, the solid solution treatment temperature is strictly controlled at 1120 DEG C.

[0056] In some embodiments, in the low-temperature dynamic plastic deformation process in the multi-scale hierarchical twin crystal preparation step, the sample is subjected to liquid nitrogen cooling treatment for 3 min before each deformation.

[0057] In some embodiments, in the heat treatment preparation step, the aging process is carried out through the protective gas.

[0058] In some embodiments, in the heat treatment preparation step, the cooling method after aging is air cooling at room temperature.

[0059] As shown in Figure 1 The preparation method of the nickel-based alloy obtained by the preparation method comprises the following steps: melting and preparing a sample, solid solution treatment at a specific temperature to obtain a specific organization, introducing a multi-scale hierarchical twin crystal under a specific plastic deformation condition, and then introducing a precipitate phase through heat treatment, and the twin crystal density is not sacrificed during the heat treatment process. Finally, a nickel-based alloy with high strength and high ductility is prepared.

[0060] The term "solid solution treatment" used in the present application refers to a process in which the equilibrium transformation is inhibited when the solid solution is solidified, and a metastable supersaturated solid solution single-phase organization is obtained.

[0061] The application introduces twin crystals which are difficult to prepare into a material matrix by a simple and efficient process, effectively changes the microstructure, shortens the aging time during heat treatment, changes the existing state of precipitated phases, so that the nickel-based alloy obtains higher strength and elongation, and the high-temperature performance is also improved.

[0062] Based on the preparation method of the nickel-based alloy with coexistence of nano-twin crystals and precipitated phases provided in the above embodiments, the application provides a nickel-based alloy with coexistence of nano-twin crystals and precipitated phases.

[0063] Among them, the nickel-based alloy has nano-twin crystals of different sizes and different orientations, and more than about 60% of the grains in the nickel-based alloy contain twin crystals. The width of the twin crystals is between 5nm and 30nm, and the size of the twin crystal network formed by the intersection (i.e. the size of the nano-grid formed between the twin crystals) is between 15nm and 800nm.

[0064] The nickel-based alloy is distributed with a high-density and uniform L12-Ni3(Al,Ti) precipitated phase, the size of which is about 5nm-10nm, and the misfit degree between the precipitated phase and the matrix is less than 0.3%, and the volume fraction of the precipitated phase is about 30% or more.

[0065] In addition, not every grain contains a twin crystal grid, and the introduction of twin crystals is more inclined to occur in grains with a grain size of less than 200μm, and the occurrence of twin crystals does not affect the orientation of the original grain itself, nor does it damage the integrity of the original grain itself.

[0066] In some embodiments, the application provides a nickel-based alloy with coexistence of nano-twin crystals and precipitated phases, and the elements of the nickel-based alloy include Ni, Cr, Al, Ti, Nb and Mo.

[0067] And the composition of the nickel-based alloy is measured by the mass percentage of elements as Cr:(8-20)%, Al:(1.3-3.6)%, Ti:(2.4-5.4)%, Nb:(1.1-3.2)%, Mo:(2.5-5.8)%, and the balance is Ni.

[0068] In some embodiments, the elements of the nickel-based alloy include Ni, Cr, Al, Ti, Nb, Mo, Fe, Mn, Si, Zr, C and Cu.

[0069] And the composition of the nickel-based alloy is measured by the mass percentage of elements as Cr:14.5%, Al:1.7%, Ti:2.6%, Nb:2.1%, Mo:3.0%, Fe:0.1%, Zr:0.04%, Mn:0.03%, Si:0.03%, C:0.05%, Cu:0.02%, and the balance is Ni.

[0070] The nickel-based alloy with nanotwin and L12-Ni3(Al, Ti) precipitate coexistence formed based on the above elements. And in the setting of the above components, due to the limitation of the existing nickel-based alloy smelting and free forging process, there are still unavoidable impurity elements in the components of the above nickel-based alloy blank and the final nickel-based alloy product, but the content of the impurity raw material is extremely small, so it is not necessary to consider the proportion of the component ratio. Further, with the optimization of the nickel-based alloy blank preparation process, the content of impurity elements in the nickel-based alloy blank is also reduced synchronously.

[0071] Some embodiments will be specifically given below, and the nickel-based alloy will be described in detail in combination with the drawings.

[0072] Example 1

[0073] A nickel-based alloy with nanotwin and precipitate coexistence is prepared, and the mass percentage of elements is: 14.5% Cr, 1.7% Al, 2.6% Ti, 2.1% Nb, 3.0% Mo, 0.1% Fe, 0.04% Zr, 0.03% Mn, 0.03% Si, 0.05% C, 0.02% Cu, and the balance is nickel and unavoidable impurity elements.

[0074] The specific preparation method is as follows:

[0075] Step one, nickel-based alloy smelting

[0076] According to the above mass percentage, each element is selected and placed in a vacuum induction melting furnace. The vacuum degree is less than 10 Pa before power heating. Continue to vacuum to 0.8, and then fill the furnace with protective gas argon. After annealing the smelted material and removing the oxide skin, vacuum consumable furnace smelting is carried out, and the vacuum process is consistent with the above. Finally, the smelted material ingot is obtained for standby;

[0077] Step two, free forging

[0078] The alloy ingot prepared in step one is heated to 1100℃ for 3h, and then hot forged into a bar blank for standby.

[0079] Step three, mechanical processing

[0080] The bar blank alloy prepared in step two is mechanically processed into a 15*15*20mm rectangular blank to facilitate the subsequent twin introduction.

[0081] Step four, solid solution treatment

[0082] Under the condition of inert gas protection, the bar blank prepared in step two is subjected to solid solution treatment at 1120℃ for 2h, and then water quenched.

[0083] Step five, multi-scale hierarchical twin preparation

[0084] The step four solid solution treated blank is subjected to plastic deformation at a temperature below -100°C in the x, y, z three-dimensional directions of the blank in turn using a rapid forging device, as shown in Figure 2 . The deformation speed is ensured to be 15 m / s each time, and the cumulative deformation in the three directions finally reaches 0.45 respectively. This process can obtain the multi-scale hierarchical twin grid in the grain interior as described above.

[0085] The microstructure and performance of the finished multi-scale hierarchical twin nickel-based alloy introduced in this embodiment are tested as follows:

[0086] The microstructure of the nickel-based alloy with coexisting nanotwins and precipitates prepared in this embodiment is observed by transmission electron microscopy and metallographic microscopy. As shown in Figure 3 , the morphology of the twin introduction can be seen from the legend. The tensile strength of the finished nickel-based alloy prepared in this embodiment is 1365 MPa, the yield strength is 1157 MPa, and the elongation is 26.3% (see Table 1 below).

[0087] Embodiment 2

[0088] This embodiment prepares multi-scale hierarchical twins in a nickel-based alloy and optimizes the heat treatment process, with the mass percentage of elements being: 14.5% Cr, 1.7% Al, 2.6% Ti, 2.1% Nb, 3.0% Mo, 0.1% Fe, 0.04% Zr, 0.03% Mn, 0.03% Si, 0.05% C, 0.02% Cu, and the balance being nickel and unavoidable impurity elements.

[0089] The specific preparation method is as follows:

[0090] Step one, nickel-based alloy smelting

[0091] According to the above mass percentage, each element is placed in a vacuum induction melting furnace, and the vacuum degree is extracted to less than 10 Pa before power heating. When the vacuum degree continues to reach 0.8, the protective gas argon is filled into the furnace. The smelted material is annealed, and after the oxide skin is removed, it is subjected to vacuum consumable furnace smelting, and the vacuum process is consistent with the above. Finally, the smelted material ingot is obtained for use.

[0092] Step two, free forging

[0093] The alloy ingot prepared in step one is heated to 1100°C for 3h of heat preservation treatment, and then hot forged into a rod blank for standby. Step three, mechanical processing

[0094] The rod blank alloy prepared in step two is mechanically processed into a 15*15*20mm rectangular blank to facilitate the subsequent twin introduction.

[0095] Step four, solution treatment

[0096] The rod blank prepared in step two was solution treated at 1120 °C for 2 h under inert gas protection, and then water quenched.

[0097] Step five, preparation of multi-scale hierarchical twins

[0098] The solution treated blank in step four was subjected to plastic deformation at a temperature below -100 °C in the x, y, and z directions of the blank in sequence using a rapid forging device, as shown in FIG. 2. The deformation speed was 15 m / s each time, and the cumulative deformation in the three directions was 0.45, respectively. This process can obtain the multi-scale hierarchical twin grid in the grain interior as described above. Figure 2

[0099] Step six, heat treatment regime

[0100] The blank subjected to twin preparation in step five was subjected to aging treatment at 750 °C for 60 min under inert gas protection, and then cooled at room temperature to obtain a sample having a nano-scale precipitate and multi-scale hierarchical twins in the interior.

[0101] The microstructure and performance of the finished nickel-based alloy introduced in this example were tested as follows:

[0102] The microstructure of the multi-scale hierarchical twin nickel-based alloy prepared in this example was observed using a metallographic microscope and a transmission electron microscope, and the structure is shown in FIG. 3. The morphology of the twins and precipitates can be seen from the figure. The tensile strength of the finished nickel-based alloy prepared in this example was 1730 MPa, the yield strength was 1527 MPa, and the elongation was 23.4% (see Table 1 below). Figure 4

[0103] Example 3

[0104] In this example, multi-scale hierarchical twins were prepared in a nickel-based alloy having the following mass percentages: 14.5% Cr, 1.7% Al, 2.6% Ti, 2.1% Nb, 3.0% Mo, 0.1% Fe, 0.04% Zr, 0.03% Mn, 0.03% Si, 0.05% C, 0.02% Cu, and the balance being nickel and unavoidable impurities.

[0105] The method for preparing the nickel-based alloy in this example was the same as in Example 2, except that the aging temperature in the heat treatment regime of step six was 700 °C.

[0106] ​​The performance of the finished multi-scale hierarchical twinned nickel-based alloy introduced in this embodiment is tested as follows: the tensile strength of the finished nickel-based alloy prepared in this embodiment is 1600 MPa, the yield strength is 1397 MPa, and the elongation is 24.8% (see Table 1 below).

[0107] Example 4

[0108] In this embodiment, multi-scale hierarchical twinning is prepared in a nickel-based alloy, and the mass percentage of elements is: 14.5% Cr, 1.7% Al, 2.6% Ti, 2.1% Nb, 3.0% Mo, 0.1% Fe, 0.04% Zr, 0.03% Mn, 0.03% Si, 0.05% C, 0.02% Cu, and the balance is nickel and inevitable impurity elements.

[0109] The method for preparing the nickel-based alloy in this embodiment is the same as that in Example 2, except that the aging temperature of the heat treatment system in step six is 800°C.

[0110] The performance of the finished multi-scale hierarchical twinned nickel-based alloy introduced in this embodiment is tested as follows: the tensile strength of the finished nickel-based alloy prepared in this embodiment is 1500 MPa, the yield strength is 1297 MPa, and the elongation is 26.2% (see Table 1 below).

[0111] Example 5

[0112] In this embodiment, multi-scale hierarchical twinning is prepared in a nickel-based alloy, and the mass percentage of elements is: 14.5% Cr, 1.7% Al, 2.6% Ti, 2.1% Nb, 3.0% Mo, 0.1% Fe, 0.04% Zr, 0.03% Mn, 0.03% Si, 0.05% C, 0.02% Cu, and the balance is nickel and inevitable impurity elements.

[0113] The method for preparing the nickel-based alloy in this embodiment is the same as that in Example 2, except that the aging time of the heat treatment system in step six is 90 min.

[0114] The performance of the finished multi-scale hierarchical twinned nickel-based alloy introduced in this embodiment is tested as follows: the tensile strength of the finished nickel-based alloy prepared in this embodiment is 1650 MPa, the yield strength is 1320 MPa, and the elongation is 25.4% (see Table 1 below).

[0115] Example 6

[0116] A multi-scale hierarchical twinned nickel-based alloy was prepared in this example, which contains the following elements in mass percent: 14.5% Cr, 1.7% Al, 2.6% Ti, 2.1% Nb, 3.0% Mo, 0.1% Fe, 0.04% Zr, 0.03% Mn, 0.03% Si, 0.05% C, 0.02% Cu, and the balance being nickel and unavoidable impurities.

[0117] The nickel-based alloy prepared in this example was prepared in the same way as in Example 1, except that the aging time in step six was 120 min.

[0118] The multi-scale hierarchical twinned nickel-based alloy prepared in this example was tested for performance as follows: the tensile strength of the finished product nickel-based alloy prepared in this example was 1500 MPa, the yield strength was 1110 MPa, and the elongation was 28.7% (see Table 1 below).

[0119] Example 7

[0120] A multi-scale hierarchical twinned nickel-based alloy was prepared in this example, which contains the following elements in mass percent: 14.5% Cr, 1.7% Al, 2.6% Ti, 2.1% Nb, 3.0% Mo, 0.1% Fe, 0.04% Zr, 0.03% Mn, 0.03% Si, 0.05% C, 0.02% Cu, and the balance being nickel and unavoidable impurities.

[0121] The nickel-based alloy prepared in this example was prepared in the same way as in Example 1, except that the cumulative deformation in three directions was ultimately 0.41.

[0122] The multi-scale hierarchical twinned nickel-based alloy prepared in this example was tested for performance as follows: the tensile strength of the finished product nickel-based alloy prepared in this example was 1342 MPa, the yield strength was 1134 MPa, and the elongation was 26.5% (see Table 1 below).

[0123] Example 8

[0124] A multi-scale hierarchical twinned nickel-based alloy was prepared in this example, which contains the following elements in mass percent: 14.5% Cr, 1.7% Al, 2.6% Ti, 2.1% Nb, 3.0% Mo, 0.1% Fe, 0.04% Zr, 0.03% Mn, 0.03% Si, 0.05% C, 0.02% Cu, and the balance being nickel and unavoidable impurities.

[0125] The nickel-based alloy prepared in this example was prepared in the same way as in Example 2, except that the cumulative deformation in three directions was ultimately 0.41.

[0126] The performance of the finished multi-scale hierarchical twinned nickel-based alloy introduced in this embodiment is tested as follows: the tensile strength of the finished nickel-based alloy prepared in this embodiment is 1740 MPa, the yield strength is 1519 MPa, and the elongation is 23.6% (see Table 1 below).

[0127] Example 9

[0128] In this embodiment, multi-scale hierarchical twinning is prepared in a nickel-based alloy, and the mass percentage of elements is: 14.5% Cr, 1.7% Al, 2.6% Ti, 2.1% Nb, 3.0% Mo, 01% Fe, 0.04% Zr, 0.03% Mn, 0.03% Si, 0.05% C, 0.02% Cu, and the balance is nickel and inevitable impurity elements.

[0129] The specific preparation method is as follows:

[0130] Step one, nickel-based alloy smelting

[0131] According to the above mass percentage, each element is placed in a vacuum induction melting furnace, and the vacuum degree is less than 10 Pa before power heating. Continue to vacuum to 0.8, and then fill the furnace with protective gas argon. After annealing the smelted material and removing the oxide skin, vacuum consumable furnace smelting is carried out, and the vacuum process is consistent with the above. Finally, the smelted material ingot is obtained for use.

[0132] Step two, free forging

[0133] The alloy ingot prepared in step one is heated to 1100℃ for 3h, and then hot forged into a rod blank for standby.

[0134] Step three, mechanical processing

[0135] The rod blank alloy prepared in step two is mechanically processed into a 15*15*20mm rectangular blank to facilitate the subsequent introduction of twinning.

[0136] Step four, solid solution treatment

[0137] Under the condition of inert gas protection, the rod blank prepared in step two is subjected to solid solution treatment at 1120℃ for 2h, and then water quenched.

[0138] Step five, multi-scale hierarchical twinning preparation

[0139] The solid solution treated blank in step four is subjected to plastic deformation at a temperature below -100℃ in the x, y, and z three-dimensional directions of the blank in sequence using a rapid forging device, such as Figure 2The deformation speed was guaranteed to be 15 m / s each time, and the cumulative deformation in three directions finally reached 0.25, respectively. The above-mentioned multi-scale hierarchical twin grid in the grain can be obtained by the process.

[0140] The performance test of the finished multi-scale hierarchical twin nickel-based alloy introduced in the embodiment is as follows: the tensile strength of the finished nickel-based alloy prepared in the embodiment is 1020 MPa, the yield strength is 830 MPa, and the elongation is 35.0% (see Table 1 below).

[0141] Example 10

[0142] In this embodiment, a multi-scale hierarchical twin is prepared in a nickel-based alloy, and the mass percentage of elements is: 14.5% Cr, 1.7% Al, 2.6% Ti, 2.1% Nb, 3.0% Mo, 0.1% Fe, 0.04% Zr, 0.03% Mn, 0.03% Si, 0.05% C, 0.02% Cu, and the balance is nickel and inevitable impurity elements.

[0143] The specific preparation method is as follows:

[0144] Step one, nickel-based alloy smelting

[0145] According to the above mass percentage, each element is placed in a vacuum induction melting furnace, and the vacuum degree is less than 10 Pa before power heating. Continue to vacuum to 0.8, and then fill the furnace with protective gas argon. After annealing the smelted material and removing the oxide skin, vacuum consumable furnace smelting is carried out, and the vacuum process is consistent with the above. Finally, the smelted material ingot is obtained for use;

[0146] Step two, free forging

[0147] The alloy ingot prepared in step one is heated to 1100℃ for 3h, and then hot forged into a bar blank for standby;

[0148] Step three, mechanical processing

[0149] The bar blank alloy prepared in step two is mechanically processed into a 15*15*20mm rectangular blank to facilitate the subsequent twin introduction;

[0150] Step four, solid solution treatment

[0151] Under the condition of inert gas protection, the bar blank prepared in step two is subjected to solid solution treatment at 1120℃ for 2h, and then water quenched.

[0152] Step five, multi-scale hierarchical twin preparation

[0153] The billet after step four solid solution treatment is subjected to plastic deformation in the x, y, and z three-dimensional directions at a temperature below 100 °C in a cycle, as shown in FIG. 2. The deformation speed is ensured to be 15 m / s, and the cumulative deformation in the three directions is finally 0.25, respectively. This process can obtain the multi-scale hierarchical twin grid in the grain interior as described above. Figure 2

[0154] Step six, heat treatment system

[0155] The billet after step five twin preparation is subjected to aging treatment for 60 min in a heating furnace at a temperature of 750 °C under inert gas protection. After the sample is cooled at room temperature, a sample with nanoscale precipitates and multi-scale hierarchical twins in the interior is obtained.

[0156] The performance of the finished multi-scale hierarchical twin nickel-based alloy introduced in this embodiment is tested as follows: the tensile strength of the finished nickel-based alloy prepared in this embodiment is 1280 MPa, the yield strength is 980 MPa, and the elongation is 33.6% (see Table 1 below).

[0157] Example 11

[0158] In this embodiment, multi-scale hierarchical twins are prepared in a nickel-based alloy, and the mass percentage of elements is: 14.5% Cr, 1.7% Al, 2.6% Ti, 2.1% Nb, 3.0% Mo, 0.1% Fe, 0.04% Zr, 0.03% Mn, 0.03% Si, 0.05% C, 0.02% Cu, and the balance is nickel and inevitable impurity elements.

[0159] The method for preparing the nickel-based alloy in this embodiment is the same as that in Example 7, except that the cumulative deformation in the three directions is finally 0.15, respectively.

[0160] The performance of the nickel-based alloy in this embodiment is tested as follows: the tensile strength of the finished nickel-based alloy prepared in this embodiment is 910 MPa, the yield strength is 750 MPa, and the elongation is 38.0% (see Table 1 below).

[0161] Table 1 is a comparison chart of performance tests of each embodiment

[0162]

[0163]

[0164] ​From the above table, it can be seen that the nickel-based alloy prepared by the present application has significant advantages and excellent comprehensive performance, especially when the deformation reaches a certain value, the excellent comprehensive performance of the material can be embodied, and the embodiments 7, 8 and 9 only embody good single performance.

[0165] Those skilled in the art can easily understand that the above description is only the preferred embodiment of the present application, and is not used to limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A nickel-based alloy exhibiting the coexistence of nanotwins and precipitated phases, characterized in that, The microstructure consists of a coexistence of nanotwins and precipitated phases; The nanotwins are distributed within at least 60% of the grains; the precipitated phase is distributed in the nickel-based alloy with a volume fraction greater than 30%. The nickel-based alloy comprises Ni, Cr, Al, Ti, Nb, Mo, Fe, Mn, Si, Zr, C, and Cu; and the composition of the nickel-based alloy is as follows, measured by elemental mass percentage: Cr: 14.5%, Al: 1.7%, Ti: 2.6%, Nb: 2.1%, Mo: 3.0%, Fe: 0.1%, Zr: 0.04%, Mn: 0.03%, Si: 0.03%, C: 0.05%, Cu: 0.02%, with the balance being Ni.

2. The nickel-based alloy with coexistence of nanotwins and precipitated phases according to claim 1, characterized in that, The width of the nanotwins is 5 nm to 30 nm, and the size of the twin network formed by the intersection of the nanotwins is 15 nm to 800 nm. The mismatch between the precipitated phase and the nickel matrix is ​​less than 0.3%, and the size is 5 nm to 10 nm.

3. The nickel-based alloy with coexistence of nanotwins and precipitated phases according to claim 1, characterized in that, The orientation and integrity of the grains containing the nanotwins remain unchanged before and after the formation of the nanotwins.

4. The method for preparing a nickel-based alloy with coexistence of nanotwins and precipitated phases as described in any one of claims 1-3, characterized in that, Includes the following steps: (1) The plate or block nickel-based alloy billet to be treated is subjected to solid solution treatment and then water quenched to obtain a single-phase nickel-based alloy with uniform structure; (2) The single-phase nickel-based alloy is subjected to cyclic plastic deformation in three dimensions at temperatures below -100 °C. (3) After step (2), heat treatment is performed and cooled to obtain a nickel-based alloy with nanotwins and precipitated phases coexisting.

5. The method for preparing a nickel-based alloy with coexisting nanotwins and precipitated phases according to claim 4, characterized in that, In step (1); The solution treatment involves holding the solution at 1120 °C for 1.5 to 2 hours.

6. The method for preparing a nickel-based alloy with coexistence of nanotwins and precipitated phases according to claim 4, characterized in that, In step (2); The rate of plastic deformation is 15 m / s ± 5 m / s; the cumulative deformation in the three-dimensional directions reaches 0.4 ~ 0.45 respectively; wherein, the deformation is the ratio of the initial height to the final height after deformation.

7. The method for preparing a nickel-based alloy with coexisting nanotwins and precipitated phases according to claim 4, characterized in that, In step (3); The heat treatment is carried out under inert gas protection at a temperature of 650 ℃ to 850 ℃ for 60 to 120 min.

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