A high-strength and high-toughness alloy material, its preparation method and application

Abstract

The present invention relates to a high-strength and high-toughness alloy material, its preparation method and application, and specifically belongs to the technical field of alloy material preparation. The alloy material consists of a cemented carbide outer ring and a ferroalloy inner ring. The raw materials of the cemented carbide outer ring, calculated by mass percentage, include the following components: 65-68% WC, 18-20% Co, 10-12% Ni, 0.5-0.8% rare earth mixture, 2.0-3.0% composite carbide; the raw materials of the ferroalloy inner ring, calculated by mass percentage, include the following components: 18-22% TiC, 4.0-5.0% Cr, 7.5-8.5% W, 3.5-4.5% Mo, 0.8-1.2% V, 1.5-2.0% Ni, and the balance is iron. Through WC-other refractory carbide gradient composite and process optimization, the present invention can better balance densification and grain control, and achieve the synergistic improvement of high hardness and high toughness.

Description

Technical Field

[0001] The present invention relates to the technical field of alloy material preparation, and more specifically, to a high-strength and high-toughness alloy material and a preparation method and application thereof. Background Art

[0002] In the fields of aerospace, mining machinery, high-speed rolling, etc., the requirements for the comprehensive performance of materials are becoming increasingly stringent, especially wear-resistant and impact-resistant materials with high hardness, high toughness and excellent heat resistance. Although traditional cemented carbide has excellent wear resistance, its toughness is insufficient and it is prone to brittle fracture when subjected to impact loads. Although single iron-based alloys such as high-entropy alloys and stainless steel have certain toughness, their hardness and wear resistance are difficult to meet the requirements of extreme working conditions. In recent years, composite structural materials have become a research hotspot, but the existing technology still has the following key problems:

[0003] Cemented carbide increases hardness by reducing the content of the binder phase, but this results in a significant decrease in fracture toughness and is unable to adapt to dynamic load environments. After the introduction of carbides to inhibit grain growth and strengthen the alloy matrix, some alloys are prone to crack deflection failure, but excessive addition will destroy the fluidity of liquid phase sintering and form pore defects. In addition, it is difficult to achieve effective diffusion bonding between carbides and the iron matrix in the preparation process, and there are often pores or brittle phases at the interface, leading to interlayer delamination and reduced mechanical properties.

[0004] Based on the above statements, the present invention provides a high-strength and high-toughness alloy material and a preparation method and application thereof. Summary of the invention

[0005] In order to solve the above-mentioned problems, the present invention provides a high-strength and high-toughness alloy material and a preparation method and application thereof. The specific technical solution is as follows:

[0006] A high-strength and high-toughness alloy material, composed of a cemented carbide outer ring and an iron alloy inner ring, wherein the cemented carbide outer ring raw material comprises the following components by mass percentage: 65-68% WC, 18-20% Co, 0.5-0.8% mixed rare earth, 2.0-3.0% composite carbide, and the balance is Ni;

[0007] The ferroalloy inner ring raw material includes the following components in percentage by mass: 18-22% TiC, 4.0-5.0% Cr, 7.5-8.5% W, 3.5-4.5% Mo, 0.8-1.2% V, 1.5-2.0% Ni, and the balance is iron.

[0008] In the above technical solution, composite carbide is added to the components of the cemented carbide outer ring to improve hardness and wear resistance; at the same time, the ratio of Co and Ni in the system is adjusted, and through the subsequent design of the pretreatment process and the sintering process, the formation of Ni-Co alloy in the system is promoted, and its effect as a binder phase is promoted, further improving toughness and bonding strength. In the ferroalloy inner ring, the contents of TiC, Cr, W, Mo and Ni are optimized to balance the strength and toughness of the ferroalloy inner ring.

[0009] Further, the mixed rare earth is obtained by mixing Ce, La and Pr according to the mass ratio of (55-60):(30-35):(3-5).

[0010] Further, the composite carbide is obtained by mixing VC and other refractory carbides.

[0011] Further, the other refractory carbide is TaC and / or NbC.

[0012] Preferably, the mass ratio of VC to other refractory carbides is (1.5-2.0):(0.5-1.0).

[0013] The present invention also provides a preparation method of a high-strength and high-toughness alloy material, which specifically includes the following steps:

[0014] S1. Ball-mill the raw materials of the cemented carbide outer ring with a planetary ball mill, with a ball-to-material ratio of 3:1, add anhydrous ethanol and stearic acid, and set the ball-milling time to 3.5-4 hours; then dry at 90-100 °C for 10-12 hours, and pass through a 200-300 mesh sieve to obtain the cemented carbide outer ring powder;

[0015] S2. Ball-mill the raw materials of the ferroalloy inner ring with a planetary ball mill, with a ball-to-material ratio of 4:1, add anhydrous ethanol and stearic acid, and set the ball-milling time to 4-6 hours; then dry at 90-100 °C for 10-12 hours, and pass through a 300-400 mesh sieve to obtain the ferroalloy inner ring powder;

[0016] S3. Prepare a double-layer jacket mold, load the cemented carbide outer ring powder into the outer jacket, and load the ferroalloy inner ring powder into the inner jacket, and perform pre-pressing treatment by cold isostatic pressing; then transfer it to a vacuum hot pressing sintering furnace for sintering treatment, and perform pressure treatment by hot isostatic pressing. After pressing, cool at a rate of 1-5 °C per minute to 500-520 °C, and then cool with the furnace to room temperature to obtain a high-strength and high-toughness alloy material.

[0017] Further, in step S1, the mass ratio of the raw materials of the cemented carbide outer ring, anhydrous ethanol and stearic acid is (300-400):100:(0.3-0.7).

[0018] Further, in step S2, the mass ratio of the ferroalloy inner ring raw material, absolute ethanol, and stearic acid is (300 - 400):100:(0.3 - 0.5).

[0019] Further, in step S3, the pressure for the pre-pressing treatment is set to 200 - 250 Mpa, and the pressure holding time is 15 - 20 minutes.

[0020] Further, in step S3, the specific operations for the sintering treatment and the pressure application treatment are as follows:

[0021] Under vacuum conditions, the temperature is raised to 500 - 520 °C at a rate of 5 - 10 °C per minute, held for 30 - 60 minutes, then the temperature is further raised to 800 - 850 °C at a rate of 10 - 20 °C per minute, held for 45 - 60 minutes. An inert gas is filled into the system and pressure application is started, the pressure is set to 4 - 5 Mpa, the temperature is raised to 1200 - 1300 °C, held under pressure for 80 - 100 minutes, then the pressure is raised to 7 - 9 Mpa and the temperature is raised to 1300 - 1350 °C, held under pressure for 100 - 120 minutes.

[0022] The third object of the present invention is to provide the application of the above high-strength and high-toughness alloy material in a roll structure.

[0023] In summary, the present invention has the following beneficial effects:

[0024] 1. In the technical solution of the present invention, the performance of the final alloy material is improved by optimizing the respective component settings of the cemented carbide outer ring and the ferroalloy inner ring. In the cemented carbide outer ring, WC is used as the main hard-phase skeleton, which forms a solid solution with Co and Ni in the formula to inhibit the abnormal growth of WC grains under high WC content, maintain a fine-grained structure in the components, and improve the thermal fatigue resistance of the matrix. And composite carbides are used to strengthen the matrix. VC improves wear resistance, and other refractory carbides enhance high-temperature stability. At the same time, VC can form a solid solution with WC, and cooperate with other refractory carbides to hinder dislocation movement, synergistically improving the hardness and creep resistance of the material. The Co and Ni components, on the one hand, act as the binder phase, optimize the fluidity during liquid-phase sintering, promote the metallurgical bonding between the outer ring and the inner ring, and enhance the interface bonding strength. On the other hand, they act together with the mixed rare earths. The mixed rare earths form a liquid phase at high temperatures, promoting element diffusion and interface wetting, purifying the grain boundaries by removing impurities such as oxygen and sulfur, and the Co-Ni complex inhibits the segregation of composite carbides, further improving the material strength. In the ferroalloy inner ring components, the iron matrix is used as the main hard phase, and TiC is used as the second hard phase. TiC forms a Ti(C,N)-Fe eutectic phase with iron, enhancing the interface metallurgical bonding, and through component optimization, improving the mechanical properties and interface bonding effect of the ferroalloy inner ring. During the sintering process, the liquid phase of Co promotes the mutual diffusion of TiC and Fe to form a metallurgical bond, and forms a double-binder phase system with Ni in the inner ring, synergistically improving the comprehensive performance. The WC in the outer ring and the TiC in the inner ring form a composite hard phase. At the same time, the Ni-Co alloy in the outer ring and the Fe matrix in the inner ring form a transition layer through diffusion, enhancing the interlayer bonding strength. The outer cemented carbide provides high hardness, and the inner ferroalloy ensures high toughness, finally obtaining a high-strength and high-toughness alloy material.

[0025] 2. In the technical solution of the present invention, high-strength and high-toughness alloy materials are formed by setting different ball-milling treatment procedures for the raw materials of the cemented carbide outer ring and the ferroalloy inner ring. A higher ball-to-material ratio and ball-milling time are set for the raw materials of the ferroalloy inner ring to promote the bonding effect between the outer ring material and the inner ring material. For the cemented carbide outer ring, setting a lower-strength ball-milling procedure can avoid excessive fragmentation of hard particles, maintain its high-hardness characteristics, and at the same time prevent excessive refinement of binder phases such as Co and Ni, ensuring the liquid-phase formation ability during subsequent sintering. For the ferroalloy inner ring, the hardness of the iron-based powder is relatively low. In order to enhance the dispersion uniformity of complex components such as TiC, W, and Mo, it is necessary to improve the grinding efficiency to adapt to the outer ring material and avoid composition segregation.

[0026] 3. In the technical solution of the present invention, a pre-pressing treatment procedure, a sintering treatment, and a pressure treatment procedure are provided in the specific preparation process of the high-strength and high-toughness alloy material. Through the pre-pressing treatment, the alloy material is preliminarily formed. The Co-Ni binder phase in the outer ring is initially formed into a liquid-phase network during pre-pressing, and the Fe matrix in the inner ring forms a uniform structure through pre-pressing, avoiding the segregation of TiC and ensuring that the powder does not displace during subsequent sintering. Through the sintering and pressure treatment with a temperature gradient, the organic residues are fully removed at 500-520 °C to avoid the generation of pores subsequently. Then, the temperature is raised to the solid-phase sintering temperature (800-850 °C) to promote element diffusion and the formation of the Co-Ni liquid phase. The temperature is continuously raised and pressure is applied to promote the wetting of WC particles by the Co-Ni liquid phase and its diffusion into the inner-ring Fe matrix, promoting the metallurgical bonding of the Co-Ni liquid phase and the TiC-Fe eutectic, and ensuring the interlayer reliability. Finally, the temperature and pressure treatment are continued to promote the deformation of each component to eliminate residual pores, improve the density, and fill microcracks. Detailed implementation manners

[0027] The following will combine the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0028] Example 1

[0029] A high-strength and high-toughness alloy material is composed of a cemented carbide outer ring and an iron alloy inner ring. Among them, the raw materials of the cemented carbide outer ring, by mass percentage, include the following components: 65% WC, 18% Co, 0.5% mixed rare earths, 2.0% composite carbide, and the balance is Ni; the mixed rare earths are obtained by mixing Ce, La, and Pr in a mass ratio of 55:30:3; the composite carbide is obtained by mixing VC and other refractory carbides, and the mass ratio of VC to other refractory carbides is 1.5:0.5, and the other refractory carbide is TaC.

[0030] The raw materials of the iron alloy inner ring, by mass percentage, include the following components: 18% TiC, 4.0% Cr, 7.5% W, 3.5% Mo, 0.8% V, 1.5% Ni, and the balance is iron.

[0031] The preparation method of the above high-strength and high-toughness alloy material includes the following steps:

[0032] S1. The hard alloy outer ring raw material is ball-milled by a planetary ball mill with a ball-to-material ratio of 3:1. Add absolute ethanol and stearic acid, and set the ball-milling time to 3.5 hours. Then dry it at 90 °C for 10 hours, and pass through a 200-mesh sieve to obtain the hard alloy outer ring powder. The mass ratio of the hard alloy outer ring raw material, absolute ethanol, and stearic acid is 300:100:0.3;

[0033] S2. The ferroalloy inner ring raw material is ball-milled by a planetary ball mill with a ball-to-material ratio of 4:1. Add absolute ethanol and stearic acid, and set the ball-milling time to 4 hours. Then dry it at 90 °C for 10 hours, and pass through a 300-mesh sieve to obtain the ferroalloy inner ring powder. The mass ratio of the ferroalloy inner ring raw material, absolute ethanol, and stearic acid is 300:100:0.3.

[0034] S3. Prepare a double-layer jacket mold. Load the hard alloy outer ring powder into the outer jacket and the ferroalloy inner ring powder into the inner jacket, and perform pre-pressing treatment by cold isostatic pressing. The pressure of the pre-pressing treatment is set to 200 Mpa, and the pressure holding time is 15 minutes. Then transfer it to a vacuum hot pressing sintering furnace for sintering treatment, and perform pressure increasing treatment by hot isostatic pressing. The specific operation is as follows: Set the vacuum degree to 1×10 -3 Pa, heat it to 500 °C at a rate of 5 °C / minute, hold for 30 minutes, then continue to heat it to 800 °C at a rate of 10 °C / minute, hold for 45 minutes, fill the system with inert gas and start to increase the pressure. The pressure is set to 4 Mpa, raise the temperature to 1200 °C, hold the pressure and temperature for 80 minutes, then raise the pressure to 7 Mpa and raise the temperature to 1300 °C, hold the pressure and temperature for 100 minutes; After pressurization, cool it to 500 °C at a rate of 3 °C / minute, and then cool it to room temperature with the furnace, and a high-strength and high-toughness alloy material is obtained.

[0035] Example 2

[0036] A high-strength and high-toughness alloy material is composed of a hard alloy outer ring and a ferroalloy inner ring. Among them, the hard alloy outer ring raw material, by mass percentage, includes the following components: 67% WC, 19% Co, 0.7% mixed rare earth, 2.5% composite carbide, and the balance is Ni; The mixed rare earth is obtained by mixing Ce, La, and Pr according to a mass ratio of 58:33:4; The composite carbide is obtained by mixing VC and other refractory carbides, and the mass ratio of VC and other refractory carbides is 1.8:0.8, and the other refractory carbide is TaC.

[0037] The ferroalloy inner ring raw material, by mass percentage, includes the following components: 20% TiC, 4.5% Cr, 8.0% W, 4.0% Mo, 1.0% V, 1.8% Ni, and the balance is iron.

[0038] The preparation method of the above high-strength and high-toughness alloy material includes the following steps:

[0039] S1. The cemented carbide outer ring raw material is ball-milled by a planetary ball mill with a ball-to-material ratio of 3:1. Add absolute ethanol and stearic acid, and set the ball-milling time to 4 hours. Then dry it at 90 °C for 12 hours, and pass through a 300-mesh sieve to obtain the cemented carbide outer ring powder. The mass ratio of the cemented carbide outer ring raw material, absolute ethanol, and stearic acid is 350:100:0.5;

[0040] S2. The ferroalloy inner ring raw material is ball-milled by a planetary ball mill with a ball-to-material ratio of 4:1. Add absolute ethanol and stearic acid, and set the ball-milling time to 5 hours. Then dry it at 100 °C for 12 hours, and pass through a 400-mesh sieve to obtain the ferroalloy inner ring powder. The mass ratio of the ferroalloy inner ring raw material, absolute ethanol, and stearic acid is 350:100:0.4.

[0041] S3. Prepare a double-layer jacket mold. Load the cemented carbide outer ring powder into the outer jacket and the ferroalloy inner ring powder into the inner jacket, and perform pre-pressing treatment by cold isostatic pressing. The pressure of the pre-pressing treatment is set to 230 Mpa, and the pressure holding time is 20 minutes. Then transfer it to a vacuum hot press sintering furnace for sintering treatment, and perform pressure increasing treatment by hot isostatic pressing. The specific operation is as follows: Set the vacuum degree to 1×10 -3 Pa, heat it to 510 °C at a rate of 10 °C / minute, hold for 45 minutes, then continue to heat it to 830 °C at a rate of 15 °C / minute, hold for 55 minutes, fill the system with inert gas and start pressurizing, set the pressure to 5 Mpa, raise the temperature to 1270 °C, hold for 90 minutes while maintaining pressure, then raise the pressure to 8 Mpa and raise the temperature to 1330 °C, hold for 120 minutes while maintaining pressure. After pressurizing, cool it to 510 °C at a rate of 5 °C / minute, and then cool it to room temperature with the furnace, thus obtaining a high-strength and high-toughness alloy material.

[0042] Example 3

[0043] A high-strength and high-toughness alloy material is composed of a cemented carbide outer ring and a ferroalloy inner ring. Among them, the cemented carbide outer ring raw material, by mass percentage, includes the following components: 68% WC, 20% Co, 0.8% mixed rare earths, 3.0% composite carbide, and the balance is Ni; the mixed rare earths are obtained by mixing Ce, La, and Pr in a mass ratio of 60:35:5; the composite carbide is obtained by mixing VC and other refractory carbides, and the mass ratio of VC to other refractory carbides is 2:1, and the other refractory carbide is NbC.

[0044] The ferroalloy inner ring raw material, by mass percentage, includes the following components: 22% TiC, 5.0% Cr, 8.5% W, 4.5% Mo, 1.2% V, 2.0% Ni, and the balance is iron.

[0045] The preparation method of the above high-strength and high-toughness alloy material comprises the following steps:

[0046] S1. Ball-mill the raw material of the cemented carbide outer ring by using a planetary ball mill, with a ball-to-material ratio of 3:1. Add absolute ethanol and stearic acid, and set the ball-milling time to 4 hours. Then dry it at 100 °C for 12 hours, and obtain the cemented carbide outer ring powder after passing through a 300-mesh sieve. The mass ratio of the raw material of the cemented carbide outer ring, absolute ethanol and stearic acid is 400:100:0.7;

[0047] S2. Ball-mill the raw material of the ferroalloy inner ring by using a planetary ball mill, with a ball-to-material ratio of 4:1. Add absolute ethanol and stearic acid, and set the ball-milling time to 6 hours. Then dry it at 100 °C for 12 hours, and obtain the ferroalloy inner ring powder after passing through a 400-mesh sieve. The mass ratio of the raw material of the ferroalloy inner ring, absolute ethanol and stearic acid is 400:100:0.5.

[0048] S3. Prepare a double-layer jacket mold. Load the cemented carbide outer ring powder into the outer jacket, and load the ferroalloy inner ring powder into the inner jacket. Perform pre-pressing treatment by cold isostatic pressing, and set the pressure of the pre-pressing treatment to 250 Mpa and the pressure-holding time to 20 minutes. Then transfer it to a vacuum hot-pressing sintering furnace for sintering treatment, and perform pressure-increasing treatment by hot isostatic pressing. The specific operation is as follows: set the vacuum degree to 1×10 -3 Pa, heat it to 520 °C at a rate of 10 °C per minute, keep it warm for 60 minutes, then continue to heat it to 850 °C at a rate of 20 °C per minute, keep it warm for 60 minutes, fill the system with inert gas and start to pressurize, set the pressure to 5 Mpa, raise the temperature to 1300 °C, keep it warm and pressurized for 100 minutes, then raise the pressure to 9 Mpa and raise the temperature to 1350 °C, keep it warm and pressurized for 120 minutes; after pressurizing, cool it to 520 °C at a rate of 5 °C per minute, and then cool it to room temperature along with the furnace, thus obtaining a high-strength and high-toughness alloy material.

[0049] Comparative Example 1

[0050] The difference between this comparative example and Example 1 lies in that in the raw material of the cemented carbide outer ring, the composite carbide is obtained by mixing VC and TiC according to a mass ratio of 1.5:0.5.

[0051] Comparative Example 2

[0052] The difference between this comparative example and Example 1 lies in that in the composite carbide of the raw material of the cemented carbide outer ring, the mass ratio of VC to other refractory carbides is 5:1.

[0053] Comparative Example 3

[0054] The difference between this comparative example and Example 1 is that in steps S1 and S2 of this comparative example, the same ball milling process is used for the cemented carbide outer ring raw material and the ferroalloy inner ring raw material. Specifically, in the ball milling process, the ball-to-material ratio is set to 4:1, anhydrous ethanol and stearic acid are added, and the ball milling time is set to 4 hours; then it is dried at 90 °C for 10 hours and sieved through a 300-mesh sieve; the mass ratio of the cemented carbide outer ring raw material or the ferroalloy inner ring raw material, anhydrous ethanol and stearic acid is 300:100:0.3.

[0055] Comparative Example 4

[0056] The difference between this comparative example and Example 1 is that in step S3 of this comparative example, no pre-pressing treatment is set, and it is directly transferred to a vacuum hot pressing sintering furnace for sintering treatment, and hot isostatic pressing is used for pressure treatment.

[0057] Comparative Example 5

[0058] The difference between this comparative example and Example 1 is that in step S3 of this comparative example, it is transferred to a vacuum hot pressing sintering furnace for sintering treatment, and hot isostatic pressing is used for pressure treatment. The specific operation is as follows:

[0059] Set the vacuum degree to 1×10 -3 Pa, heat up to 500 °C at a rate of 5 °C per minute, hold for 30 minutes, then fill the system with inert gas and start pressurizing, the pressure is set to 7 Mpa, raise the temperature to 1300 °C, hold for 225 minutes; after pressurizing, cool to 500 °C at a rate of 3 °C per minute, and then cool to room temperature with the furnace.

[0060] Performance Test

[0061] The high-strength and high-toughness alloy materials prepared in Examples 1-3 and Comparative Examples 1-5 of the present invention are made into samples with a size of 75*Φ10, and the performance of the products in the group is tested. The specific test methods are as follows:

[0062] Hardness test: Referring to the method in ISO 3738, the Rockwell hardness of the product is tested, and the test load is set to 10 kgf;

[0063] Flexural strength test: Referring to the method in ISO 3327, the flexural strength of the product is tested by a three-point bending test, the span is set to 30 mm, and the loading rate is 0.5 mm / min;

[0064] Wear loss test: Referring to the method in ASTM G65, the wear loss of the product is tested by an abrasive wear test, the test load is set to 10 N, grinding wheel: SiC (particle size 60 mesh), wear distance: 1000 m;

[0065] Fracture toughness test: The fracture toughness of the product was tested according to the method described in GB∕T 21143-2014, and the indentation load was set at 200 N.

[0066] The specific performance test results are shown in Table 1 below:

[0067] Table 1 Performance test results of high-strength and high-toughness alloy materials prepared in examples and comparative examples

[0068]

[0069] It can be seen from the results shown in Table 1 above that:

[0070] Through WC-other refractory carbide gradient composite and process optimization, Examples 1-3 are significantly superior to the comparative examples in terms of hardness, strength, wear resistance and toughness, verifying the importance of the synergy between component design and process parameters. Examples 1-3 achieve the balance between hardness and toughness through WC-other refractory carbide composite and Ni-Co double binder phase, and are suitable for high-end roll materials. Due to composition or process defects, the performance of Comparative Examples 1-5 has decreased significantly. For example, the hardness of Comparative Example 4 is only 63 HRA, and the toughness of Comparative Example 3 is only 52 MPa·m 1 / 2 , verifying the necessity of the synergy between components and processes.

[0071] Specifically, it can be seen from the results in Comparative Example 1 that using titanium carbide to reinforce the matrix instead of other refractory carbides, the hardness of TiC is lower than that of other refractory carbides such as NbC and TaC, and there is a lattice mismatch with WC, resulting in the weakening of the synergistic effect of the composite hard phase, being unable to significantly hinder the movement of dislocations, and the limited improvement in wear resistance, and the effect is not as good as the compounding effect of VC and TaC, NbC.

[0072] It can be seen from the results in Comparative Example 2 that the proportion of the composite carbide VC is too high, and VC forms an excessive solid solution with WC, resulting in insufficient refinement of WC grains. And VC occupies too much space of the Co-Ni binder phase, reducing the fluidity of the liquid phase and increasing the content of V2O5 in the system, damaging the protective layer. Therefore, the hardness of the final alloy material increases slightly, but the toughness decreases significantly and the impact resistance deteriorates.

[0073] In Comparative Example 3, the finer-grained powder of the outer ring of the cemented carbide can promote the densification effect of the structure and reduce pore defects. However, in the solution of the present invention, components such as TiC, as part of the alloy material, are not differentially treated, resulting in problems of segregation and stress concentration, and the compatibility with the inner ring material can better improve the overall strength performance of the material.

[0074] In Comparative Example 4 and Comparative Example 5, the preloading treatment can better fix the powder and amplify the effects of gradient heat treatment and pressurization treatment. Through gradient sintering and pressurization treatment, densification and grain control can be better balanced, achieving a synergistic improvement in high hardness and high toughness.

[0075] In the description of the specification, the description referring to terms such as "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0076] The above content is only an example and illustration of the present invention. Those skilled in the art of the present technology can make various modifications or supplements to the specific embodiments described or use similar ways to replace them. As long as they do not deviate from the invention or exceed the scope defined by the claims of the present invention, they should all fall within the protection scope of the present invention.

Claims

1. A high-strength and high-toughness alloy material, characterized in that, It is composed of a cemented carbide outer ring and a ferroalloy inner ring. The raw materials of the cemented carbide outer ring, by mass percentage, include the following components: 65 - 68% WC, 18 - 20% Co, 0.5 - 0.8% mixed rare earths, 2.0 - 3.0% composite carbide, and the balance is Ni; the composite carbide is obtained by mixing VC and other refractory carbides, and the mass ratio of VC to other refractory carbides is (1.5 - 2.0):(0.5 - 1.0), and the other refractory carbide is TaC and / or NbC; The raw materials of the ferroalloy inner ring, by mass percentage, include the following components: 18 - 22% TiC, 4.0 - 5.0% Cr, 7.5 - 8.5% W, 3.5 - 4.5% Mo, 0.8 - 1.2% V, 1.5 - 2.0% Ni, and the balance is iron.

2. The high-strength and high-toughness alloy material according to claim 1, characterized in that, The mixed rare earths are obtained by mixing Ce, La, and Pr in a mass ratio of (55 - 60):(30 - 35):(3 - 5).

3. A method for preparing a high-strength and high-toughness alloy material as described in any one of claims 1-2, characterized in that, Specifically, it includes the following steps: S1. Perform ball milling on the raw materials of the cemented carbide outer ring, add anhydrous ethanol and stearic acid, set the ball milling time to 3.5 - 4 hours, and the ball-to-material ratio to 3:1; then dry at 90 - 100 °C for 10 - 12 hours, and pass through a 200 - 300 mesh sieve to obtain the cemented carbide outer ring powder; S2. Perform ball milling on the raw materials of the ferroalloy inner ring, add anhydrous ethanol and stearic acid, set the ball milling time to 4 - 6 hours, and the ball-to-material ratio to 4:1; then dry at 90 - 100 °C for 10 - 12 hours, and pass through a 300 - 400 mesh sieve to obtain the ferroalloy inner ring powder; S3. Prepare a double-layer jacket mold, load the cemented carbide outer ring powder into the outer jacket, and the ferroalloy inner ring powder into the inner jacket, and perform pre-pressing treatment by cold isostatic pressing; then transfer it to a vacuum hot pressing sintering furnace for sintering treatment, and perform pressure increasing treatment by hot isostatic pressing. After pressure increasing, cool it at a rate of 1 - 5 °C per minute to 500 - 520 °C, and then cool it with the furnace to room temperature to obtain a high-strength and high-toughness alloy material; among them, the specific operations of the sintering treatment and the pressure increasing treatment are: under vacuum conditions, heat it up to 500 - 520 °C at a rate of 5 - 10 °C per minute, hold for 30 - 60 minutes, then continue to heat it up to 800 - 850 °C at a rate of 10 - 20 °C per minute, hold for 45 - 60 minutes, fill the system with inert gas and start to increase the pressure, set the pressure to 4 - 5 MPa, increase the temperature to 1200 - 1300 °C, hold the pressure and temperature for 80 - 100 minutes, then increase the pressure to 7 - 9 MPa and increase the temperature to 1300 - 1350 °C, hold the pressure and temperature for 100 - 120 minutes.

4. The preparation method of a high-strength and high-toughness alloy material according to claim 3, characterized in that, In step S1, the mass ratio of the raw materials of the cemented carbide outer ring, anhydrous ethanol, and stearic acid is (300 - 400):100:(0.3 - 0.7).

5. The preparation method of a high-strength and high-toughness alloy material according to claim 3, characterized in that, In step S2, the mass ratio of the raw materials of the ferroalloy inner ring, anhydrous ethanol, and stearic acid is (300 - 400):100:(0.3 - 0.5).

6. The preparation method of a high-strength and high-toughness alloy material according to claim 3, characterized in that, In step S3, the pressure setting for the pre-pressing treatment is 200 - 250 MPa, and the pressure holding time is 15 - 20 minutes.

7. Application of a high-strength and high-toughness alloy material as described in any one of claims 1-2 in a roll structure.

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