Precipitation-hardening high-speed steel material based on interface engineering and fractional precipitation strengthening and preparation method of precipitation-hardening high-speed steel material

Abstract

The invention discloses a precipitation-hardening high-speed steel material based on interface engineering and fractional precipitation strengthening and a preparation method of the precipitation-hardening high-speed steel material. The precipitation-hardening high-speed steel material comprises a steel matrix, a precipitation phase and a whisker reinforced phase, wherein the precipitation phase and the whisker reinforced phase are dispersed and distributed in the steel matrix; according to the precipitation-hardening high-speed steel material, on the basis that the Co content is remarkably reduced (5%-10%), by introducing multiple alloy elements such as Ni, Ti, Mo, W, Cr, V, Mn, Nb, B, Ta, Zr and rare earth (La and Ce) and a whisker reinforcement phase, the elasticity modulus, strength, toughness and high-temperature performance are comprehensively improved, the powder metallurgy technology is adopted, pre-deformation is combined for inducing a nanoscale precipitated phase, and multi-stage aging heat treatment is combined, so that the precipitation-hardening high-speed steel material is obtained. And accurate regulation and control on the microstructure and the performance of the material are realized.

Description

Technical Field

[0001] The present invention relates to the field of powder metallurgy technology, specifically to the field of powder metallurgy steel materials, and particularly to a precipitation hardening high-speed steel material based on interface engineering and hierarchical precipitation strengthening and a preparation method thereof. Background Art

[0002] Precipitation hardening high-speed steels occupy an irreplaceable position in high-end cutting tools, precision molds and other fields due to their good strength-toughness matching, excellent hot hardness and outstanding machining performance. Traditional precipitation hardening high-speed steels, such as Fe-Co-Mo / W series carbon-free high-speed steels, usually rely on a high content of Co element to obtain excellent comprehensive properties (as described in CN116770197A, CN111793773B, CN114561600B). Co plays a role in precipitation hardening high-speed steels mainly through mechanisms such as solid solution strengthening the matrix, enhancing the high-temperature strength of the alloy, and promoting the precipitation of specific types of intermetallic compounds. However, the high Co content significantly increases the manufacturing cost of the material and causes a series of problems such as resource scarcity, supply chain security and environmental impact, seriously restricting its application in a wider industrial field.

[0003] In addition, there are still limitations in the existing technology in terms of elastic modulus improvement, interface regulation and the coordination of multiple strengthening mechanisms, and it is difficult to fully meet the stringent requirements for the comprehensive properties of materials in high-end application fields. Specifically, the deficiencies of the existing technology are mainly reflected in: (1) Although CN114686783A and CN114686782A disclose methods for improving the elastic modulus by alloying and hard second phases, the improvement amplitude of the elastic modulus is limited: it is difficult to significantly improve the elastic modulus of precipitation hardening high-speed steels without sacrificing other key properties (such as toughness, high-temperature properties), which limits its further expansion in application fields such as high-rigidity precision tools and molds; (2) Insufficient research on precipitation phase interface engineering: The existing technology pays insufficient attention to the regulation and optimization of the interface structure between the precipitation phase and the matrix. As a key bridge connecting the matrix and the strengthening phase in the composite material, the structure and properties of the interface have a significant impact on the macroscopic properties of the material. The failure to effectively utilize interface engineering means limits the potential for material property improvement; (3) Insufficient development of hierarchical precipitation strengthening mechanism: A single strengthening mechanism is difficult to meet the comprehensive requirements of high-performance precipitation hardening high-speed steels for multiple indicators such as strength, toughness and high-temperature properties. Developing and utilizing the hierarchical precipitation strengthening mechanism to achieve the synergistic effect of multiple strengthening mechanisms is an effective way to improve the comprehensive properties of materials, but the existing technology still needs to be further studied in this regard. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the first object of the present invention is to provide a precipitation hardening high-speed steel material based on interface engineering and hierarchical precipitation strengthening. The precipitation hardening high-speed steel material provided by the present invention, on the basis of significantly reducing the Co content (5-10%), realizes the comprehensive improvement of elastic modulus, strength, toughness and high-temperature performance by introducing a variety of alloying elements such as Ni, Ti, Mo, W, Cr, V, Mn, Nb, B, Ta, Zr, rare earths (La, Ce), etc. and whisker reinforcement phases.

[0005] The second object of the present invention is to provide a preparation method of a precipitation hardening high-speed steel material based on interface engineering and hierarchical precipitation strengthening. The preparation method of the present invention adopts a powder metallurgy process, combined with pre-deformation induced nano-scale precipitation phases and multi-stage aging heat treatment, to realize the precise control of the microstructure and properties of the material.

[0006] In order to achieve the above-mentioned invention objects, the technical solutions adopted by the present invention are as follows:

[0007] A precipitation hardening high-speed steel material based on interface engineering and hierarchical precipitation strengthening of the present invention, the precipitation hardening high-speed steel material comprises a steel matrix, precipitation phases dispersed in the steel matrix and whisker reinforcement phases;

[0008] In the precipitation hardening high-speed steel material, it contains Ni, Mo, W, Ti, Cr, V, Mn, Nb, Ta, Zr, Co, and interfacial active elements; the interfacial active elements are selected from at least one of Re and B, the Re is selected from at least one of La, Ce, Y, and Sc, and the mass fraction of Co in the precipitation hardening high-speed steel material is 5-10 wt.%.

[0009] The precipitation-hardening high-speed steel material provided by the present invention adopts a low-cobalt multi-alloy composition design: significantly reducing the Co element content to 5-10 wt.%, and compoundly adding a variety of alloy elements such as Ni, Mo, W, Ti, Cr, V, Mn, Nb, Ta, Zr, etc. By reducing the Co content, the material cost is greatly reduced, the resource utilization efficiency is improved, and the synergistic effect between alloy elements is utilized through the multi-alloying design. Through mechanisms such as solid solution strengthening, precipitation strengthening, and grain boundary strengthening, the strength loss caused by the low-cobalt composition is effectively compensated, and the comprehensive service performance of the material is comprehensively improved; Interface-active elements are added. Under the drive of thermodynamics, the interface-active elements segregate at the interface between the precipitation phase and the martensite matrix. By changing the interface chemical composition and electronic structure, the interface microstructure is effectively regulated, the interface bonding strength is enhanced, the interface coherence is optimized, and the interface stress concentration is reduced. Finally, the efficient transfer of load between the matrix and the precipitation phase is realized, and the elastic modulus, yield strength, and fracture toughness of the material are significantly improved; In addition, the present invention also introduces whisker reinforcement phases (such as silicon carbide whiskers, zirconia whiskers), further improving the elastic modulus and high-temperature performance of the material. Under the synergism of the above components, the comprehensive improvement of elastic modulus, strength, toughness, and high-temperature performance is achieved.

[0010] In a preferred embodiment, the mass fraction of the interface-active element in the precipitation-hardening high-speed steel material is 0.05-0.4%. Experiments have found that the addition amount of the interface-active element cannot be excessive. If it is excessive, it will not only fail to further optimize the material properties, but will instead form coarse and brittle second phases (such as borides, rare earth compounds, TCP phases, etc.) at the grain boundaries or within the grains, which will have the opposite effect. These harmful phases will become the origin of crack initiation, significantly reducing the toughness, plasticity, and fatigue life of the steel. At the same time, it may also deteriorate the hot working performance and welding performance of the material, and may interfere with the expected strengthening effect of other key alloy elements, ultimately comprehensively damaging the comprehensive performance and economic benefits of the precipitation-hardening high-speed steel.

[0011] In a further preferred embodiment, the interface-active element is selected from B and La. The mass fraction of B in the precipitation-hardening high-speed steel material is 0.01-0.03%, and the mass fraction of La in the precipitation-hardening high-speed steel material is 0.04-0.37%. Experiments have found that the compound addition of B and La elements can fully exert their synergistic effect, maximizing the interface engineering effect. Among them, the B element mainly segregates at the grain boundaries and the interface of the precipitation phase, reducing the interface energy and improving the interface bonding strength; the La element mainly combines with interstitial impurities O and S, purifies the grain boundaries, reduces grain boundary segregation, and improves the grain boundary strength.

[0012] Preferably, the whisker reinforcement is silicon carbide whiskers, and the volume fraction of the whisker reinforcement in the precipitation hardening high-speed steel material is 1-5%, preferably 3-5%. Silicon carbide whiskers have extremely high elastic modulus and tensile strength, and excellent high-temperature strength and thermal stability. They have good thermodynamic and chemical compatibility with the steel matrix and are ideal reinforcement for steel matrix composites.

[0013] Preferably, for the precipitation hardening high-speed steel material, by mass percentage, its composition is as follows: Co: 5-10%; Mo: 5-10%; W: 2-6%; Ni: 5-10%; Ti: 2-5%; Cr: 1-3%; V: 1-2%; Mn: 0.5-1%; Nb: 0.3-0.5%; Ta: 0.5-1%; Zr: 0.1-0.5%; interfacial active element 0.05-0.4%; the balance is Fe, whisker reinforcement and unavoidable impurities.

[0014] Further preferably, for the precipitation hardening high-speed steel material, by mass percentage, its composition is as follows: Co: 8-10%; Mo: 8-10%; W: 4-5%; Ni: 8-7%; Ti: 3-4%; Cr: 2-3%; V: 1.5-2%; Mn: 0.6-0.8%; Nb: 0.4-0.5%; Ta: 0.7-0.8%; Zr: 0.3-0.5%; B: 0.02-0.03%; La: 0.2-0.3%; the balance is Fe, whisker reinforcement and unavoidable impurities.

[0015] The present invention also provides a preparation method of a precipitation hardening high-speed steel material based on interface engineering and hierarchical precipitation strengthening. Interface active element raw materials and other metal raw materials are proportionally taken and ball-milled to obtain pre-deformed mixed powder. The pre-deformed mixed powder is mixed with whiskers and a carbon source to obtain a mixed material. The mixed material is pressed into a green body. The green body is sintered to obtain a sintered body. Then the sintered body is subjected to solution quenching treatment to obtain a solution body. The solution body is subjected to warm deformation treatment, and finally multi-stage aging heat treatment is carried out to obtain the product.

[0016] The preparation method of the present invention is as follows: First, the surfactant element raw material and other metal raw materials (metal raw materials other than those in the surfactant element) are subjected to high-energy ball milling for pre-deformation mixing, aiming to introduce defects such as high-density dislocations and grain boundaries inside the powder particles, significantly increasing the nucleation density of nano-scale precipitate phases during the subsequent aging process. Then, the pre-deformed alloy powder, whisker powder, and carbon source are mixed in proportion and homogenized in a low-energy mixer to obtain a mixed powder. The mixed powder is successively compacted and sintered to obtain a sintered blank. After the sintered blank is subjected to high-temperature solution quenching treatment, warm deformation treatment is immediately carried out to further introduce defects such as high-density dislocations and grain boundaries inside the material. Finally, multi-stage aging heat treatment is used to promote the nucleation of nano-scale precipitate phases, forming precipitate phases of different sizes and types in the matrix, realizing hierarchical precipitation strengthening, and optimizing the matching of strength and toughness.

[0017] In the present invention, the surfactant element raw material is an intermediate alloy powder or elemental powder containing surfactant elements. All the raw material powders used are commercially available high-purity powders, and the whiskers are high-purity silicon carbide whiskers.

[0018] In a preferred embodiment, the surfactant element raw material, other metal raw materials, and a molding agent are proportionally taken and ball milled under a protective atmosphere to obtain a pre-deformed mixed powder.

[0019] Further preferably, the rotation speed of the ball milling is 200 - 300 r / min, the time is 48 - 96 h, and the ball-to-material ratio is 4 - 8:1.

[0020] By using the above ball milling conditions for high-energy ball milling to pre-deform and mix the metal powders, defects such as high-density dislocations and grain boundaries can be introduced inside the powder particles.

[0021] Further preferably, the molding agent is selected from at least one of paraffin, PEG, and PVB, and the addition amount of the molding agent is 2 - 5% of the total mass of the surfactant element raw material and other metal raw materials.

[0022] In a preferred embodiment, the carbon source is carbon black.

[0023] In the actual operation process, the pre-deformed mixed powder, whiskers, and carbon black can be evenly mixed by using a low-energy mixer. The low-energy mixer can be a drum ball mill or a V-type mixer.

[0024] In a preferred embodiment, the compacting and forming is cold isostatic pressing or die pressing, the pressing pressure is 150 - 200 MPa, and the pressure holding time is 20 - 30 s.

[0025] In a preferred embodiment, the sintering process is as follows: First, heat up to 550 - 650 °C in a vacuum environment, then introduce a protective atmosphere and heat up to 1300 - 1400 °C, and hold for 1 - 3 h.

[0026] In the present invention, pre-sintering is first carried out in a vacuum environment (the temperature rises from room temperature to 550 - 650 °C), the purpose of which is to remove the forming agent, and then high-temperature sintering is carried out under a protective atmosphere (preferably high-purity Ar gas) to achieve sintering densification.

[0027] In a preferred embodiment, the solution quenching treatment process is as follows: solution treatment is carried out at 1180 - 1260 °C for 0.5 - 1 h, and then immediately quenched in oil to room temperature.

[0028] In a preferred embodiment, the total deformation amount of the warm deformation treatment is 10 - 30%, and the temperature of the warm deformation treatment is 300 - 500 °C. In the present invention, the warm deformation treatment after solution quenching is the key step of "pre-deformation induced nano-precipitation". Deforming in this temperature range, the material not only has a certain plasticity (is easier to deform and less likely to crack compared to cold deformation), but also can effectively inhibit the occurrence of dynamic recovery and dynamic recrystallization. This enables a large number of dislocations to proliferate, move, and form complex dislocation structures (such as dislocation cells, dislocation walls, etc.). At the same time, it may refine some grains or generate sub-grain boundaries. These introduced crystal defects (mainly high-density dislocations) will serve as the preferred nucleation sites for nano-scale precipitate phases during subsequent aging heat treatment. And a large number of uniformly distributed nucleation sites can significantly increase the nucleation rate of precipitate phases and inhibit their growth, so it is more conducive to obtaining dispersed and finer nano-scale precipitate phases during subsequent aging. This is compared with the precipitation phases in the undeformed material that tend to nucleate and grow at a few positions such as the original grain boundaries, and can more effectively hinder the movement of dislocations, thus greatly enhancing the precipitation strengthening effect.

[0029] If pure cold deformation is used, although it can also introduce high-density dislocations, for high-alloyed high-speed steel, its deformation resistance is large, work hardening is severe, the material has poor plasticity, is easy to crack, and the deformation is difficult to be uniform. Warm deformation improves the plasticity of the material by moderately increasing the temperature. If the temperature is too high (entering the hot deformation zone), the material will undergo significant dynamic recovery and dynamic recrystallization, which will consume a large number of dislocations, reduce the nucleation sites, and is not conducive to subsequent dispersed precipitation strengthening. At the same time, too high a temperature may also cause some undesired coarse phases to precipitate prematurely and grain growth.

[0030] In addition, in the present invention, when the total deformation amount of the warm deformation treatment is controlled within the scope of the present invention, the performance of the final material is optimal. If the deformation amount is too large, first, it will lead to severe work hardening, reducing the forming ability and yield rate of the material; second, the stored energy of deformation is too high. During the subsequent heating process of aging treatment, even if the aging temperature itself is not high, it may be more likely to trigger recrystallization, resulting in grain coarsening and a decrease in dislocation density, thus losing the beneficial effects of pre-deformation; third, it may lead to non-uniformity of the final structure and properties. In addition, too large a deformation amount requires more processing passes, resulting in increased energy consumption and reduced production efficiency, which does not meet the requirements of low cost.

[0031] Preferably, the warm deformation treatment is warm rolling deformation.

[0032] Preferably, the multi-stage aging heat treatment process is to perform pre-aging treatment, first-stage aging treatment, and second-stage aging treatment in sequence; the pre-aging treatment process is: holding at 700 - 750 °C for 2 - 5 min and then air cooling; the first-stage aging treatment process is: holding at 550 - 650 °C for 0.5 - 2 h and then air cooling; the second-stage aging treatment process is: holding at 450 - 550 °C for 2 - 4 h and then air cooling, and the temperature of the second-stage aging treatment is 50 - 150 °C lower than that of the first-stage aging treatment.

[0033] In the multi-stage aging heat treatment of the present invention, in the higher temperature aging stage (pre-aging + first-stage aging), coarse precipitate phases mainly composed of refractory alloy elements such as Mo, W, Nb, and Ta (for example, Mo- and W-rich Laves phases, μ phases, M6C-type carbides, and TaC carbides rich in Ta) are preferentially nucleated and precipitated as "skeleton" phases, which pin the martensite grain boundaries, effectively hinder grain boundary slip and long-range dislocation movement, and significantly improve the strength, hardness, and high-temperature service performance of the material; in the lower temperature aging stage (second-stage aging), fine and dispersed precipitate phases mainly composed of elements such as Ni, Ti, and V (for example, Ni3Ti and V-rich MC-type carbides) are mainly precipitated, further refining the martensite matrix structure and achieving high-efficiency dispersion strengthening, and significantly improving the fracture toughness and fatigue resistance of the material.

[0034] Experiments have found that only the combination of short-term high-temperature pre-aging treatment, first-stage aging treatment, and second-stage aging treatment can form a sufficient number and evenly distributed initial cores of nano-scale precipitate phases. If the pre-aging treatment is not carried out, it may lead to insufficient formation of a sufficient number and evenly distributed initial cores of nano-scale precipitate phases inside the material, which will result in insufficient quantity, poor size control, or uneven distribution of the "skeleton" phases formed during the subsequent first-stage aging, making it difficult to effectively play their role in pinning grain boundaries and improving high-temperature performance. At the same time, this may also affect the nucleation and precipitation of fine and dispersed phases during the second-stage low-temperature aging, resulting in a weakened strengthening effect.

[0035] However, only short-term pre-aging can be carried out. If the pre-aging time is too long, it will cause premature and excessive growth and coarsening of the initially formed nanoscale cores at a relatively high temperature. This may not only make some precipitate phases that should be finely regulated in the subsequent stages become too coarse, reducing their strengthening efficiency and even damaging toughness, but also consume excessive solute elements such as Mo, W, Nb, and Ta in the matrix. This premature depletion of solutes will seriously affect the optimized formation of the "skeleton" phase in the subsequent first stage and the precipitation quantity and dispersion degree of fine and dispersed strengthening phases such as Ni, Ti, and V during the second-stage low-temperature aging, thus destroying the cooperative strengthening mechanism of multi-stage aging and ultimately possibly leading to a decline rather than an increase in the comprehensive mechanical properties of the material (especially the combination of strength and toughness and fatigue resistance).

[0036] During the actual operation process, finally, necessary subsequent treatments such as machining are carried out on the materials subjected to multi-stage aging heat treatment to obtain the final products.

[0037] Beneficial effects

[0038] The precipitation-hardening high-speed steel material provided by the present invention realizes high performance based on the interface engineering and hierarchical precipitation strengthening mechanism, combined with technical means such as multi-element alloying, whisker reinforcement, pre-deformation-induced nano-precipitation, and multi-stage aging heat treatment. Its main principles and beneficial effects are as follows:

[0039] 1. Low-cobalt strategy and significant cost control advantages: The Co element content is significantly reduced to the range of 5-10 wt.%. On the premise of ensuring the high performance of the material, the manufacturing cost is greatly reduced, the dependence on scarce strategic metal cobalt resources is effectively alleviated, the resource utilization efficiency and economy of the material are significantly improved, and it fully conforms to the concept and trend of green and sustainable development of modern manufacturing.

[0040] 2. Synergistic strengthening effect of multi-element alloying: The exquisitely designed multi-element alloy composition system (Fe-Co-Ni-Mo-W-Ti-Cr-V-Mn-Nb-Ta-Zr) constructs multiple strengthening mechanisms such as solid solution strengthening, precipitation strengthening, and grain boundary strengthening inside the material through complex interactions of alloying elements, realizing the complementary advantages and synergistic effects among alloying elements. It not only effectively makes up for the strength loss caused by low cobalt content, but also significantly improves the comprehensive service performance of the material as a whole.

[0041] 3. Interface engineering to improve performance: Interface-active elements (B, rare earth elements) segregate at the interface between the precipitate phase and the matrix, optimize the interface structure, improve the interface bonding strength, improve the load transfer efficiency, and significantly improve the elastic modulus, strength, and toughness of the material.

[0042] 4. Hierarchical precipitation strengthening and optimization matching: The multi-stage aging heat treatment process enables precise control of the precipitation behavior of different types and sizes of precipitate phases, and successfully constructs a hierarchical precipitation microstructure of coarse precipitate phases + fine precipitate phases within the material, achieving multi-scale synergistic strengthening. During the aging stage at a higher temperature (pre-aging + the first-stage aging), coarse precipitate phases mainly composed of refractory alloying elements such as Mo, W, Nb, and Ta preferentially nucleate and precipitate (for example, Laves phases rich in Mo and W, μ phases, M6C-type carbides, and TaC carbides rich in Ta), serving as "skeleton" phases to pin the martensite grain boundaries, effectively hindering grain boundary slip and long-range dislocation movement, and significantly improving the strength, hardness, and high-temperature service performance of the material; during the aging stage at a lower temperature (the second-stage aging), fine and dispersed precipitate phases mainly composed of elements such as Ni, Ti, and V mainly precipitate (for example, Ni3Ti, MC-type carbides rich in V), further refining the martensite matrix structure and achieving efficient dispersion strengthening, significantly enhancing the fracture toughness and fatigue resistance of the material.

[0043] 5. Whisker reinforcement phase further improves elastic modulus and high-temperature performance: By introducing a whisker reinforcement phase with ultra-high elastic modulus and excellent high-temperature strength characteristics, following the mixture law of composites, the overall elastic modulus and high-temperature strength of the matrix material are effectively improved.

[0044] 6. Pre-deformation induced nano-precipitate phases: By combining powder pre-deformation and warm deformation after solution quenching, a large number of defects such as high-density dislocations and grain boundaries are introduced into the material in combination, providing a large number of nucleation sites for the nucleation of nano-scale precipitate phases during the subsequent aging heat treatment process, effectively promoting the uniform and refined precipitation of nano-scale precipitate phases, and greatly enhancing the precipitation strengthening effect.

[0045] The present invention overcomes the deficiencies of the prior art. Through the integrated application of innovative technologies such as low-cobaltization, multi-element alloying, interface engineering, hierarchical precipitation strengthening, whisker reinforcement, pre-deformation induced nano-precipitation, and multi-stage aging heat treatment, a precipitation-hardening high-speed steel material with low cost and high performance and its preparation method are provided. The precipitation-hardening high-speed steel prepared by the present invention significantly improves the elastic modulus, strength, toughness, and high-temperature performance while significantly reducing the Co content, and has broad industrial application prospects. Brief Description of the Drawings

[0046] Figure 1 It is a transmission electron microscope picture of Example 1 of the present invention, showing the martensite matrix and larger "skeleton" μ phases. Detailed Embodiments

[0047] To better explain the present invention, the technical solutions and effects of the present invention will be described in detail below through specific embodiments. However, the embodiments of the present invention are not limited thereto.

[0048] Among the following raw materials, the D50 particle size of the pure metal powder is 1-10 μm and the oxidation amount is less than 0.5%; the B element and La element are introduced by adding Fe-B master alloy powder and LaB6 powder respectively, and the whisker reinforcement phase is high-purity β-SiC whisker powder (diameter 100-500 nm, length 10-50 μm).

[0049] In the following cases, the ball milling medium is anhydrous ethanol, and based on the raw material powder, the dosage of the ball milling medium is 0.7 mL / g; the ball milling speed is 250 r / min.

[0050]

[0051] Example 1

[0052] A precipitation hardening high-speed steel material based on interface engineering and hierarchical precipitation strengthening, the chemical composition of the high-speed steel material is shown in Table 1. The preparation steps are as follows:

[0053] 1. Powder preparation: Mix pure metal powder, Fe-B master alloy powder, LaB6 powder, silicon carbide whisker powder, and 5 wt.% paraffin molding agent in the designed proportion, place them in a planetary high-energy ball mill, and perform pre-deformation ball milling treatment for 72 hours under the protection of an Ar gas atmosphere. The ball-to-material mass ratio is 5:1, and YG6 cemented carbide balls are selected as grinding balls. Before the ball milling starts, first pass the mixed gas for 15 min to discharge the air, and then keep a slightly positive pressure (Ar gas, 0.25 MPa) in the ball milling tank. Stop the ball milling every 12 h of ball milling, and air-cool the ball milling tank for 20 min. After the pre-deformation ball milling treatment is completed, mix the mixed powder with silicon carbide whisker powder and 0.3 wt.% carbon black powder in a predetermined proportion, place them in a drum ball mill, and use anhydrous ethanol as the ball milling medium to perform low-energy mixing and homogenization treatment. The ball milling time is set to 20 h, the rotation speed of the drum ball mill is 180 r / min, and the ball-to-material mass ratio is 2:1. The mixed powder after ball milling is dried by a vacuum negative pressure drying device to remove the anhydrous ethanol introduced during the ball milling process, and then vacuum-sealed and packaged by a vacuum packaging device to prevent powder oxidation and moisture absorption.

[0054] 2. Compaction and sintering: The mixed powder prepared in step 1) is compacted by cold isostatic pressing. The compaction pressure is set at 160 MPa and the pressure holding time is 25 s. The green compact is subjected to vacuum pre-sintering + high-temperature sintering in an argon atmosphere. The procedure for the vacuum pre-sintering stage is as follows: heat up to 120 °C and hold for 1 h, heat up to 300 °C and hold for 2 h, heat up to 350 °C and hold for 1 h, heat up to 450 °C and hold for 1 h, heat up to 600 °C and hold for 1 h, and the vacuum degree is controlled to be less than 0.01 Pa. The high-temperature sintering is carried out at 1360 °C for 2.5 h with Ar gas as the protective atmosphere, and then the furnace is cooled to room temperature.

[0055] 3. Pre-deformation induced nano-precipitates and multi-stage aging heat treatment: The sintered blank sample prepared in step 2) is first subjected to high-temperature solution treatment, held at a high temperature of 1230 °C for 40 min, and then immediately quenched in oil to room temperature. Immediately after solution quenching and before the first-stage aging treatment, the sample is subjected to warm deformation treatment, and warm rolling deformation is carried out by rolling. The warm rolling temperature is controlled at about 450 °C and the total deformation amount is controlled at about 20%. After the warm deformation treatment, the sample is immediately placed in a vacuum aging furnace for multi-stage aging heat treatment. The multi-stage aging heat treatment process is carried out according to the following parameters: ① Pre-aging treatment: 720 °C, hold for 3 min, air cooling; ② First-stage aging treatment: 610 °C, hold for 1 h, air cooling; ③ Second-stage aging treatment: 510 °C, hold for 3 h, air cooling; After the multi-stage aging heat treatment, the high-performance low-cobalt precipitation hardening high-speed steel material designed by the present invention can be obtained.

[0056] Example 2

[0057] A precipitation hardening high-speed steel material based on interface engineering and hierarchical precipitation strengthening, and the chemical composition of the high-speed steel material is shown in Table 1. The preparation steps are as follows:

[0058] 1. Powder preparation: Pure metal powder, Fe-B master alloy powder, LaB6 powder, silicon carbide whisker powder, and 5wt.% paraffin molding agent are proportioned according to the designed ratio and placed in a planetary high-energy ball mill. Under the protection of an Ar gas atmosphere, pre-deformation ball milling treatment is carried out for 72 hours. The ball-to-material mass ratio is 5:1, and YG6 cemented carbide balls are selected as grinding balls. Before ball milling starts, first pass a mixed gas for 15 minutes to discharge air, and then maintain a slightly positive pressure (Ar gas, 0.25 MPa) inside the ball mill tank. Stop ball milling every 12 hours of ball milling and let the ball mill tank air-cool for 20 minutes. After the pre-deformation ball milling treatment is completed, the mixed powder is mixed with silicon carbide whisker powder and 0.3wt.% carbon black powder according to a predetermined ratio and placed in a drum ball mill. Using anhydrous ethanol as the ball milling medium, low-energy mixing and homogenization treatment is carried out. The ball milling time is set to 20 hours, the rotation speed of the drum ball mill is 180 r / min, and the ball-to-material mass ratio is 2:1. The mixed powder after ball milling is dried through a vacuum negative pressure drying device to remove the anhydrous ethanol introduced during the ball milling process, and then vacuum-sealed and packaged through a vacuum packaging device to prevent powder oxidation and moisture absorption.

[0059] 2. Compression molding and sintering: The mixed powder prepared in step 1) is compression-molded by a cold isostatic pressing process. The pressing pressure is set to 160 MPa, and the pressure holding time is 25 s. The green compact is subjected to vacuum pre-sintering + high-temperature sintering in an argon gas atmosphere. The program for the vacuum pre-sintering stage is as follows: heat up to 120°C and hold for 1 h, heat up to 300°C and hold for 2 h, heat up to 350°C and hold for 1 h, heat up to 450°C and hold for 1 h, heat up to 600°C and hold for 1 h, and the vacuum degree is controlled to be less than 0.01 Pa. High-temperature sintering is carried out at 1370°C for 2.5 h, and the protective atmosphere is Ar gas, and then furnace-cooled to room temperature.

[0060] 3. Pre-deformation induced nano-precipitation phase and multi-stage aging heat treatment: The sintered blank sample prepared in step 2) is first subjected to a high-temperature solution treatment, held at a high temperature of 1240°C for 40 min, and then immediately quenched in oil to room temperature. Immediately before the first-stage aging treatment after solution quenching, the sample is subjected to warm deformation treatment, and warm rolling deformation is carried out by a rolling method. The warm rolling temperature is controlled at about 455°C, and the total deformation amount is controlled at about 20%. After the warm deformation treatment is completed, the sample is immediately placed in a vacuum aging furnace for multi-stage aging heat treatment. The multi-stage aging heat treatment process is carried out according to the following parameters: ① Pre-aging treatment: 730°C, hold for 3 min, air-cool; ② First-stage aging treatment: 615°C, hold for 1 h, air-cool; ③ Second-stage aging treatment: 515°C, hold for 3 h, air-cool; After the multi-stage aging heat treatment is completed, the high-performance low-cobalt precipitation hardening high-speed steel material designed by the present invention can be obtained.

[0061] Example 3

[0062] A precipitation hardening high-speed steel material based on interface engineering and hierarchical precipitation strengthening, and the chemical composition of the high-speed steel material is shown in Table 1. The preparation steps are as follows:

[0063] 1. Powder preparation: Mix pure metal powder, Fe-B master alloy powder, LaB6 powder, silicon carbide whisker powder, and 5wt.% paraffin molding agent in the designed proportion, place them in a planetary high-energy ball mill, and perform pre-deformation ball milling treatment for 72 hours under the protection of an Ar gas atmosphere. The ball-to-material mass ratio is 5:1, and YG6 cemented carbide balls are selected as grinding balls. Before ball milling starts, first pass a mixed gas for 15 minutes to discharge air, and then maintain a slightly positive pressure (Ar gas, 0.25 MPa) inside the ball mill tank. Stop ball milling every 12 hours of ball milling, and let the ball mill tank air-cool for 20 minutes. After the pre-deformation ball milling treatment is completed, mix the mixed powder with silicon carbide whisker powder and 0.3wt.% carbon black powder in a predetermined proportion, place them in a drum ball mill, use absolute ethanol as the ball milling medium, and perform low-energy mixing and homogenization treatment. The ball milling time is set to 20 hours, the rotation speed of the drum ball mill is 180 r / min, and the ball-to-material mass ratio is 2:1. The mixed powder after ball milling is dried through a vacuum negative pressure drying device to remove the absolute ethanol introduced during ball milling, and then vacuum-sealed and packaged through a vacuum packaging device to prevent powder oxidation and moisture absorption.

[0064] 2. Compression molding and sintering: The mixed powder prepared in step 1) is compression-molded by a cold isostatic pressing process, and the pressing pressure is set to 160 MPa, and the pressure holding time is 25 s. The green compact is subjected to vacuum pre-sintering + high-temperature sintering in an argon gas atmosphere. The program for the vacuum pre-sintering stage is as follows: heat up to 120°C and hold for 1 h, heat up to 300°C and hold for 2 h, heat up to 350°C and hold for 1 h, heat up to 450°C and hold for 1 h, heat up to 600°C and hold for 1 h, and the vacuum degree is controlled to be less than 0.01 Pa. High-temperature sintering is carried out at 1340°C for 2.5 h, and the protective atmosphere is Ar gas, and then furnace-cooled to room temperature.

[0065] 3. Pre-deformation induced nano-precipitates and multi-stage aging heat treatment: The sintered blank samples prepared in step 2) are first subjected to solution heat treatment at a high temperature of 1220 °C for 40 min, and then immediately quenched in oil to room temperature. Immediately after solution quenching and before the first-stage aging treatment, the samples are subjected to warm deformation treatment, and warm rolling deformation is carried out by means of roll rolling. The warm rolling temperature is controlled at about 430 °C, and the total deformation amount is controlled at about 20%. After the warm deformation treatment is completed, the samples are immediately placed in a vacuum aging furnace for multi-stage aging heat treatment. The multi-stage aging heat treatment process is carried out according to the following parameters: ① Pre-aging treatment: 710 °C, hold for 3 min, air cooling; ② First-stage aging treatment: 600 °C, hold for 1 h, air cooling; ③ Second-stage aging treatment: 500 °C, hold for 3 h, air cooling; After the multi-stage aging heat treatment is completed, the high-performance low-cobalt precipitation hardening high-speed steel material designed by the present invention can be obtained.

[0066] Comparative Example 1

[0067] The same preparation process as in Example 1 is adopted. The difference lies only in the composition.

[0068] Comparative Example 2

[0069] The same preparation process as in Example 1 is adopted. The difference lies only in the composition.

[0070] Comparative Example 3

[0071] The same preparation process as in Example 1 is adopted. The difference lies in that the whisker reinforcement phase is not added to the composition.

[0072] Comparative Example 4

[0073] Compared with Example 1, no warm deformation treatment is carried out after solution quenching.

[0074] Comparative Example 5

[0075] A precipitation hardening high-speed steel material based on interface engineering and hierarchical precipitation strengthening, and the chemical composition of the high-speed steel material is shown in Table 1. The preparation steps are as follows:

[0076] 1. Powder preparation: Pure metal powder, Fe-B master alloy powder, LaB6 powder, silicon carbide whisker powder, and 5wt.% paraffin molding agent are proportioned according to the designed ratio and placed in a planetary high-energy ball mill. Under the protection of an Ar gas atmosphere, pre-deformation ball milling treatment is carried out for 72 hours. The ball-to-material mass ratio is 5:1, and YG6 cemented carbide balls are selected as grinding balls. Before starting the ball milling, first pass a mixed gas for 15 minutes to discharge the air, and then maintain a slightly positive pressure (Ar gas, 0.25 MPa) inside the ball milling tank. Stop the ball milling every 12 hours of ball milling, and let the ball milling tank air-cool for 20 minutes. After the pre-deformation ball milling treatment is completed, the mixed powder is mixed with silicon carbide whisker powder and 0.3wt.% carbon black powder according to a predetermined ratio, placed in a drum ball mill, and low-energy mixing and homogenization treatment is carried out with absolute ethanol as the ball milling medium. The ball milling time is set to 20 hours, the rotation speed of the drum ball mill is 180 r / min, and the ball-to-material mass ratio is 2:1. The mixed powder after ball milling is dried through a vacuum negative pressure drying device to remove the absolute ethanol introduced during the ball milling process, and then vacuum-sealed and packaged through a vacuum packaging device to prevent powder oxidation and moisture absorption.

[0077] 2. Compression molding and sintering: The mixed powder prepared in step 1) is compression-molded by a cold isostatic pressing process. The pressing pressure is set to 160 MPa, and the pressure holding time is 25 s. The green compact is subjected to vacuum pre-sintering + high-temperature sintering in an argon gas atmosphere. The program for the vacuum pre-sintering stage is as follows: heat up to 120 °C and hold for 1 h, heat up to 300 °C and hold for 2 h, heat up to 350 °C and hold for 1 h, heat up to 450 °C and hold for 1 h, heat up to 600 °C and hold for 1 h, and the vacuum degree is controlled to be less than 0.01 Pa. The high-temperature sintering is carried out at 1360 °C for 2.5 h, and the protective atmosphere is Ar gas, and then the furnace is cooled to room temperature.

[0078] 3. Pre-deformation-induced nano-precipitation phase and multi-stage aging heat treatment: The sintered billet sample prepared in step 2) is first subjected to a high-temperature solution treatment, held at a high temperature of 1230 °C for 40 min, and then immediately quenched in oil to room temperature. Immediately after solution quenching and before the first-stage aging treatment, the sample is subjected to warm deformation treatment, and warm rolling deformation is carried out by a rolling method. The warm rolling temperature is controlled at about 450 °C, and the total deformation amount is controlled at about 20%. After the warm deformation treatment is completed, the sample is immediately placed in a vacuum aging furnace for aging heat treatment. The aging heat treatment process is carried out according to the following parameters: 610 °C, hold for 1 h, air-cool.

[0079]

[0080] As can be seen from the results of the above examples and comparative examples, the low-cobalt precipitation hardening high-speed steel material obtained according to the material composition and preparation process disclosed in the present invention significantly reduces the Co element content. At the same time, through the synergistic effect of a series of key technologies such as multi-element alloying, interface engineering, hierarchical precipitation strengthening, whisker reinforcement, pre-deformation induced nano-precipitation, and multi-stage aging heat treatment, the improvement of key performance indicators such as the elastic modulus, strength, toughness, and high-temperature performance of the material is achieved. For the comparative examples that are not within the material composition range or process range described in the present invention, the performance decreases due to unreasonable composition design, lack of key processes, etc.

[0081] The above are only preferred embodiments of the present invention and do not impose any limitations on the present invention. Any simple modifications, changes, and equivalent changes made to the above embodiments based on the technical essence of the invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A precipitation-hardening high-speed steel material based on interface engineering and hierarchical precipitation strengthening, characterized in that: The precipitation hardening high-speed steel material comprises a steel matrix, precipitation phases dispersed in the steel matrix, and whisker reinforcement phases; In the precipitation hardening high-speed steel material, it contains Ni, Mo, W, Ti, Cr, V, Mn, Nb, Ta, Zr, Co, and interfacial active elements; the interfacial active elements are selected from at least one of Re and B, the Re is selected from at least one of La, Ce, Y, and Sc, and the mass fraction of Co in the precipitation hardening high-speed steel material is 5-10 wt.%.

2. The precipitation hardening high-speed steel material based on interface engineering and hierarchical precipitation strengthening according to claim 1, characterized in that: The mass fraction of the interfacial active elements in the precipitation hardening high-speed steel material is 0.05-0.4%; The whisker reinforcement phase is silicon carbide whiskers, and the volume fraction of the whisker reinforcement phase in the precipitation hardening high-speed steel material is 1-5%.

3. A precipitation hardening high-speed steel material based on interface engineering and hierarchical precipitation strengthening according to claim 1 or 2, characterized in that: For the precipitation hardening high-speed steel material, by mass percentage, its composition is as follows: Co: 5-10%; Mo: 5-10%; W: 2-6%; Ni: 5-10%; Ti: 2-5%; Cr: 1-3%; V: 1-2%; Mn: 0.5-1%; Nb: 0.3-0.5%; Ta: 0.5-1%; Zr : 0.1-0.5%; interfacial active elements 0.05-0.4%; the balance is Fe, whisker reinforcement phases, and inevitable impurities.

4. A precipitation hardening high-speed steel material based on interface engineering and hierarchical precipitation strengthening according to any one of claims 1-3, characterized in that: The interfacial active elements are selected from B and La, the mass fraction of B in the precipitation hardening high-speed steel material is 0.01-0.03%, and the mass fraction of La in the precipitation hardening high-speed steel material is 0.04-0.37%.

5. The preparation method of a precipitation hardening high-speed steel material based on interface engineering and hierarchical precipitation strengthening according to any one of claims 1-4, characterized in that: Weigh the interfacial active element raw materials and other metal raw materials according to the designed ratio, perform ball milling to obtain pre-deformed mixed powder, mix the pre-deformed mixed powder with whiskers and carbon source to obtain a mixture, press the mixture into a green body, sinter the green body to obtain a sintered body, then perform solution quenching treatment on the sintered body to obtain a solution-treated body, perform warm deformation treatment on the solution-treated body, and finally perform multi-stage aging heat treatment to obtain the product.

6. The preparation method of a precipitation hardening high-speed steel material based on interfacial engineering and hierarchical precipitation strengthening according to claim 5, characterized in that: Weigh the interfacial active element raw materials, other metal raw materials and a forming agent, and perform ball milling in a protective atmosphere to obtain pre-deformed mixed powder, The rotation speed of the ball milling is 200-300 r / min, the time is 48-96 h, and the ball-to-material ratio is 4-8:1; The forming agent is selected from at least one of paraffin, PEG, and PVB, and the addition amount of the forming agent is 2-5% of the total mass of the interfacial active element raw materials and other metal raw materials; The carbon source is carbon black.

7. The preparation method of a precipitation hardening high-speed steel material based on interfacial engineering and hierarchical precipitation strengthening according to claim 5, characterized in that: The pressing into shape is cold isostatic pressing or die pressing, the pressing pressure is 150-200 MPa, and the pressure holding time is 20-30 s; The sintering process is as follows: first heat up to 550-650 °C in a vacuum environment, then introduce a protective atmosphere and heat up to 1300-1400 °C, and hold for 1-3 h.

8. The preparation method of a precipitation hardening high-speed steel material based on interface engineering and hierarchical precipitation strengthening according to claim 5, characterized in that: The process of solution quenching treatment is as follows: solution treatment is carried out at 1180 - 1260 °C for 0.5 - 1 h, and then immediately quenched in oil and cooled to room temperature.

9. The preparation method of a precipitation hardening high-speed steel material based on interface engineering and hierarchical precipitation strengthening according to claim 5, characterized in that: The total deformation amount of the warm deformation treatment is 10 - 30%, and the temperature of the warm deformation treatment is 300 - 500 °C.

10. The preparation method of a precipitation hardening high-speed steel material based on interface engineering and hierarchical precipitation strengthening according to claim 5, characterized in that: The process of multi-stage aging heat treatment is to carry out pre-aging treatment, first-stage aging treatment, and second-stage aging treatment in sequence; the process of pre-aging treatment is: heat preservation at 700 - 750 °C for 2 - 5 min and then air cooling; the process of first-stage aging treatment is: heat preservation at 550 - 650 °C for 0.5 - 2 h and then air cooling; The process of second-stage aging treatment is: heat preservation at 450 - 550 °C for 2 - 4 h and then air cooling, and the temperature of the second-stage aging treatment is 50 - 150 °C lower than that of the first-stage aging treatment.

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