Synergistically toughened cermet composite, method of making and use thereof

Abstract

The application provides a cermet composite material with synergistically improved toughness, a preparation method and application. The composite material comprises a ceramic phase and a metal bonding phase; the ceramic phase comprises a core phase and a ring phase, and the metal bonding phase comprises a crystalline phase and an amorphous phase; the refractory metal elements of the core phase and the ring phase are not overlapped, the metal bonding phase comprises two or more bonding metal elements; and the metal bonding phase further contains residual oxygen elements diffused from the ceramic phase to the metal bonding phase, and the total number of elements is more than 8. The cermet composite material provided by the application has a core-ring structure in which the ring phase completely wraps the core phase, so that a dual-phase structure in which the crystalline phase and the amorphous phase are mixed is formed in the metal bonding phase. The synergistic cooperation of the complete core-ring structure and the dual-phase bonding phase structure significantly improves the toughness of the TiC(N)-based cermet composite material, while the TiC(N)-based cermet composite material maintains a high hardness level, and has strong structural uniformity and high performance stability.

Description

Technical Field

[0001] This invention belongs to the field of metal-ceramic composite materials technology, specifically relating to a metal-ceramic composite material with synergistic strength and toughness enhancement, its preparation method, and its application. Background Technology

[0002] Ceramic composites are composite materials composed of a ceramic phase as the framework and a metallic phase as the binder. Due to their high hardness, wear resistance, and chemical inertness, cermet composites exhibit excellent applicability in moving parts in precision manufacturing and mining industries. However, the inherent brittleness of ceramic materials often limits their development, and the inverse relationship between hardness and fracture toughness remains a significant challenge in the research and development of high-performance cermet composites.

[0003] TiC(N)-based cermets primarily achieve high hardness through the ceramic phase TiC(N) and toughness through the binder phases of metals such as Co, Ni, and Fe. However, due to the relatively poor wetting properties between the TiC(N) ceramic phase and the binder phase, the fracture toughness of TiC(N)-based cermets is generally lower than that of WC-based cemented carbides. Adding second-phase carbides (such as TaC, WC, NbC, and VC) can improve the bonding strength between the ceramic and binder phases and enhance the fracture toughness of the composite material. However, numerous studies have shown that significant improvements in fracture toughness are difficult to achieve solely through interface control between the ceramic and binder phases.

[0004] To address the aforementioned issues, Chinese invention patent CN 120796810 A discloses a high-strength and tough TiC(N)-based cermet, its preparation method, and its application. This patent utilizes rare earth oxides or rare earth salts to retain a solid solution hard phase with a modulated decomposition structure within the cermet, thereby achieving higher fracture toughness than traditional cermets without reducing hardness. In Scripta Materialia 219 (2022) 114893, (Ti,Zr)C(N)-xNi cermet samples were prepared using (Ti,Zr)C(N) solid solution powder. With increasing Ni content, the modulated decomposition trend gradually decreased, and the inhibitory effect of different elements on modulated decomposition is currently unclear, making the stable preparation of modulated decomposition-type cermet composites difficult. Chinese invention patent CN118880144 A discloses a high-strength and high-toughness cermet and its preparation method. It employs a binder phase solid solution strengthening design, using the dispersed precipitation and carbonization of a slightly oversaturated strengthening metal to improve the hardness and high-temperature resistance of the cermet. However, its fracture toughness value is still below 12 MPa·m. 1 / 2Furthermore, the sintering process involves hydrogen reduction, making the process quite complex. Chinese invention patent CN 118621170 A discloses a method for preparing a bicrystalline high-entropy (Ti,M)C(N)-based cermet. The cermet prepared in this method contains as many as 11 different elements. Controlling the microstructure and properties of high-component cermets is difficult, and the low uniformity of the microstructure leads to differences in the mechanical properties of different regions of the cermet.

[0005] Therefore, how to develop a simple, structurally uniform, and stable method for preparing metal-ceramic composite materials has become a difficult problem for technicians in the field. Summary of the Invention

[0006] The main objective of this invention is to provide a metal-ceramic composite material with synergistic strength and toughness enhancement, its preparation method, and its application, so as to overcome the shortcomings of the prior art.

[0007] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a metal-ceramic composite material with synergistic strength and toughness enhancement, comprising a ceramic phase and a metal binder phase; the ceramic phase comprising (Ti, M... a C(N) core phase, and (Ti,M) a C(N) and M b The solid solution ring phase formed by C, wherein the metal binder phase includes a crystalline phase and an amorphous phase;

[0009] Among them, M a M is selected from any one or more combinations of refractory metal elements. b Combinations selected from two or more refractory metal elements, and M a and M b The elements do not overlap; the metal binder phase includes two or more binder metal elements; the metal-ceramic composite material also contains residual oxygen elements, and the residual oxygen elements diffuse from the ceramic phase to the metal binder phase; (N) indicates that N elements may be selectively included or not included; and the total number of elements in the metal-ceramic composite material is eight or more.

[0010] Secondly, the present invention also provides a method for preparing the above-mentioned metal-ceramic composite material, comprising:

[0011] Make Ti and M a The oxides were mixed with elemental carbon and subjected to a carbothermic reduction reaction, followed by crystallization at elevated temperature to obtain (Ti,M) a C(N) pre-alloyed powder;

[0012] The (Ti,M) was prepared by high-energy ball milling.a C(N) pre-alloyed powder and M b The second type of carbide powder, the metal binder phase powder, and the optional carbon powder are ball-milled together to obtain a mixed powder.

[0013] The mixed powder is pressed into shape and then subjected to vacuum sintering and partial pressure sintering in sequence.

[0014] After sintering, the sintered product is rapidly cooled at a cooling rate of not less than 100℃ / min to obtain the metal-ceramic composite material.

[0015] Thirdly, the present invention also provides the application of the above-mentioned metal-ceramic composite material in the fields of machining and oil drilling.

[0016] Compared with the prior art, the beneficial effects of the present invention include at least the following:

[0017] The metal-ceramic composite material provided by this invention has a core-ring structure in which the core phase is completely wrapped by the ring phase. Through multi-factor component control and condition control, a two-phase structure with mixed crystalline and amorphous phases is formed in the metal binder phase. The synergistic effect of the complete core-ring structure and the two-phase structure significantly improves the toughness of the TiC(N)-based metal-ceramic composite material, while maintaining a high hardness level. In addition, the composite material has strong structural uniformity and high performance stability.

[0018] The above description is merely an overview of the technical solution of the present invention. In order to enable those skilled in the art to better understand the technical means of this application and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described below in conjunction with detailed drawings. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is an X-ray diffraction pattern of the pre-alloyed powder prepared in a typical embodiment of the present invention;

[0021] Figure 2 This is an electron microscope image of the microstructure of a TiC(N)-based metal-ceramic composite material prepared in a typical embodiment of the present invention;

[0022] Figure 3This is a transmission electron microscope (TEM) image of the binder phase region of a TiC(N)-based metal-ceramic composite material prepared in a typical embodiment of the present invention.

[0023] Figure 4 This is a selected area diffraction image of the binder phase region of a TiC(N)-based metal-ceramic composite material prepared in a typical embodiment of the present invention;

[0024] Figure 5 This is an electron microscope image of the microstructure of a metal-ceramic composite material prepared in a typical comparative case of the present invention.

[0025] Figure 6 This is a transmission electron microscope (TEM) image of the binder phase region of a metal-ceramic composite material prepared in a typical comparative case of this invention.

[0026] Figure 7 This is a selected area diffraction image of the binder phase region of a metal-ceramic composite material prepared in a typical comparative case of the present invention;

[0027] Figure 8 This is an electron microscope image of the microstructure of a metal-ceramic composite material prepared in another typical comparative case of the present invention;

[0028] Figure 9 This is a transmission electron microscope (TEM) image of the binder phase region of a metal-ceramic composite material prepared in another typical comparative case of the present invention;

[0029] Figure 10 This is a selected area diffraction image of the binder phase region of a metal-ceramic composite material prepared in another typical comparative case of the present invention. Detailed Implementation

[0030] In view of the shortcomings of the prior art, the inventors of this invention, through long-term research and extensive practice, have proposed the technical solution of this invention. The following will further explain and illustrate this technical solution, its implementation process, and its principles.

[0031] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0032] This invention first provides a synergistically enhanced metal-ceramic composite material, comprising a ceramic phase and a metal binder phase; the ceramic phase comprises (Ti, M... a C(N) core phase, and (Ti,M) a C(N) and M bThe solid solution ring phase formed by C, wherein the metal binder phase comprises a crystalline phase and an amorphous phase; wherein the solid solution ring phase completely encapsulates the core phase so that the core phase and the metal binder phase do not come into contact; M a M is selected from any one or more combinations of refractory metal elements. b Combinations selected from two or more refractory metal elements, and M a and M b The elements do not overlap; the metal binder phase includes two or more binder metal elements; the metal-ceramic composite material also contains residual oxygen elements, and the residual oxygen elements diffuse from the ceramic phase to the metal binder phase; (N) indicates that N elements may be selectively included or not included; and the total number of elements in the metal-ceramic composite material is more than 8 (in this invention, other elements with a mass fraction of less than one-thousandth are considered as unavoidable impurities and are not included in the total number of elements).

[0033] A typical embodiment of the present invention generates a complete core-ring structure in the metal-ceramic composite material by controlling the elemental composition and preparation conditions (under an electron microscope, the core phase is usually black, and the ring phase is gray or white). At the same time, a two-phase structure of mixed amorphous and crystalline phases is generated when the metal binder phase is formed. The ring phase that completely encapsulates the core phase plays a role in enhancing wettability and stress buffering, avoiding the toughness loss caused by the partial core phase directly contacting the metal binder phase. Meanwhile, in the metal binder phase, the crystalline phase provides sufficient bonding strength and uniformly separates the ceramic phase, while the amorphous phase fully fills the gap between the crystalline and ceramic phases, and provides additional bonding strength and can play a role in relieving interfacial stress. The small-sized crystalline phase can strengthen the amorphous phase while providing a certain degree of coordinated deformation capability under external stress, thereby achieving a synergistic toughness improvement of TiC(N)-based metal-ceramic composite material.

[0034] In some embodiments, the components of the metal-ceramic composite material are represented as a composition, comprising:

[0035] 55-70wt% (Ti, M) a C(N) pre-alloyed powder, 10-25 wt% M b The pre-alloyed powder comprises: C2 type carbide powder, 10-20 wt% metal binder phase powder, and 0-2 wt% carbon powder; the remaining oxygen element accounts for 0.2-1.0 wt% of the pre-alloyed powder by mass ratio. In this invention, the remaining oxygen element is preferably spontaneously retained during the carbothermic reduction reaction of oxides. Based on this preparation method, 0.2-1.0 wt% oxygen content is usually spontaneously formed in the pre-alloyed powder without the need for deliberate artificial addition.

[0036] More specifically, in some embodiments, M in the pre-alloyed powder a The atomic number is 0.03-0.12, which can also be expressed as: the pre-alloyed powder comprises (Ti, M... x C(N), where x represents stoichiometry and its value ranges from 0.03 to 0.12.

[0037] In some implementations, the (Ti,M) a The particle size of the C(N) pre-alloyed powder is less than 2 μm.

[0038] Regarding the specific element types, in some implementation schemes, M a Selected from any one or more combinations of W, Mo, Ta, Nb, V, Zr, and Cr.

[0039] In some implementation schemes, M b Two or more combinations selected from W, Mo, Ta, Nb, V, and Hf.

[0040] In some embodiments, the metal binder phase comprises a combination of two or more of Co, Ni, Fe, Mo, and Al.

[0041] This invention also provides a method for preparing the metal-ceramic composite material provided in any of the above embodiments, which includes the following steps:

[0042] Make Ti and M a The oxides were mixed with elemental carbon and subjected to a carbothermic reduction reaction, followed by crystallization at elevated temperature to obtain (Ti,M) a C(N) pre-alloyed powder;

[0043] The (Ti,M) was prepared by high-energy ball milling. a C(N) pre-alloyed powder and M b The second type of carbide powder, the metal binder phase powder, and optional carbon powder are ball-milled and mixed (the amount of carbon powder added is determined according to the free carbon content in the original powder, mainly to prevent the formation of the M6C brittle phase from damaging the toughness of the metal-ceramic composite material. The presence of M6C in the metal-ceramic can be determined by phase diagram calculation or XRD, and corresponding carbon supplementation operations are performed, depending on the specific situation), to obtain a mixed powder;

[0044] The mixed powder is pressed into shape and then subjected to vacuum sintering and partial pressure sintering in sequence.

[0045] After sintering, the sintered product is rapidly cooled at a rate of not less than 100°C / min to obtain the metal-ceramic composite material. This cooling rate is maintained at least until the temperature reaches 200°C to ensure that no phase structure transformation occurs due to excessively slow cooling.

[0046] In order to obtain the metal-ceramic composite material with a complete core-ring structure and a two-phase metal-bonded phase structure as described in this invention, this invention proposes a corresponding preparation method. In addition to meeting the component characteristics and proportion characteristics mentioned above during the selection and proportioning of raw materials (for example, the raw materials need to be reduced by oxide carbothermal method to retain a portion of oxygen element, and the composition and proportion of the pre-alloyed powder need to be consistent with the proportion of ceramic phase in the metal-ceramic composite material provided above), several key points also need to be grasped during the preparation.

[0047] One is in the process of (Ti,M) a In the preparation of C(N) pre-alloyed powder, an ultra-high temperature crystallization process is added, which allows refractory metal elements to be crystallized in (Ti,M) a The pre-alloyed C(N) powder undergoes sufficient atomic-level diffusion, forming an alloyed powder rather than a physically bonded mixed powder. This is a key factor in the formation of a complete cyclic phase. High-temperature crystallization treatment achieves sufficient solid solution strengthening of the ceramic phase. At the same time, pre-alloying can control the diffusion rate of elements in the ceramic phase, thereby regulating the solid solution element content in the metal binder phase region.

[0048] Secondly, high-energy ball milling must be used during powder mixing, and the milling speed and time must be guaranteed to provide sufficient surface energy for the subsequent formation of the two-phase structure: the high-energy milling balls transfer energy to the powder, generating extremely high strain, strain rate, and a large number of crystal defects. This allows the binder phase to accumulate enough energy, which is conducive to the initiation of the transformation to the amorphous state from the grain boundary region.

[0049] Third, the cooling process must be rapid cooling, with a cooling rate (absolute value) of at least 100 ℃ / min. Rapid cooling is one of the important kinetic factors for the formation of amorphous phases.

[0050] Fourth, through the control of raw material composition, the TiC(N)-based metal ceramic composite material contains at least eight kinds of elements. The increase in the number of elements provides thermodynamic conditions for the formation of amorphous structure. There are large differences in atomic size between components, which makes the atomic stacking more compact and generates strong local strain, hindering atomic diffusion and lattice reconstruction. At this time, the remaining small amount of oxygen elements will form strong bonds with refractory metal elements to form a unique short-range or medium-range ordered structure, which can significantly reduce the diffusion and rearrangement ability of atoms, and kinetically inhibit the nucleation and growth of crystalline phase, ultimately forming a two-phase metal bonded phase structure of amorphous phase + crystalline phase.

[0051] In this embodiment of the invention, the synergistic combination of the above factors forms the combined effect of the complete core-ring structure and the two-phase binder phase structure, thereby synergistically improving the strength and toughness of the metal-ceramic composite material.

[0052] However, although the present invention has proposed the above-mentioned preparation method and provided sufficient examples, this does not mean that the preparation method of the metal-ceramic composite material with complete core-ring structure and dual-phase structure provided by the present invention is unique. If those skilled in the art use different preparation methods to obtain metal-ceramic composite materials with the same structural characteristics, they still utilize the completely novel material structure and synergistic toughening principle proposed by the present invention, and it also falls within the feasible scope of the present invention.

[0053] Furthermore, the atmosphere for the carbothermic reduction reaction can be a nitrogen-containing atmosphere to convert Ti into the Ti(C,N) phase. Of course, the ceramic phase that can be toughened by this invention is not limited to the Ti(C,N) system. When nitrogen is not introduced, the target ceramic phase for toughening can also be the TiC system. This is why "(N)" is used in this invention to indicate whether or not N element is included.

[0054] Regarding the specific preparation conditions, in some embodiments, the carbothermic reduction reaction is carried out at a temperature of 1400-1600 °C, and the reaction time is controlled within 1 hour to avoid prolonged oxygen consumption leading to (Ti,M) degradation. a The residual oxygen content in the C(N) pre-alloyed powder is too low, and the lower limit of the reaction time is sufficient to form (Ti,M) a The carbothermic reduction reaction time limit can be determined based on experimental results of different component contents and / or different reaction temperatures, without strict limitation, using C(N) pre-alloyed powder as the standard; the crystallization treatment temperature is 1800-2200 ℃.

[0055] In some implementations, the high-energy ball mill has a ball milling speed greater than 300 r / min, a ball milling time of not less than 24 h, and a ball-to-material ratio of 8:1-15:1.

[0056] Furthermore, for high-energy ball milling, the milling jar is typically made of cemented carbide, but is not limited to this. Ethanol is recommended as the milling medium, but again, it is not limited to this; any material capable of performing the corresponding high-energy ball milling function is acceptable. When using wet high-energy ball milling, drying is required after the ball milling and mixing process. The drying temperature is 70-90 °C until the powder is completely dry. Of course, the specific drying method is not limited; this is merely an example.

[0057] In some embodiments, the vacuum sintering temperature is 1400-1500 °C and the time is 1-3 h; the partial pressure sintering temperature is 1400-1500 °C, the pressure is 10-50 kPa, and the time is 1-3 h.

[0058] In some embodiments, the compression molding uses a molding agent as an additive, the amount of which is 3-5 wt%, and a degreasing sintering step is included before the vacuum sintering to remove organic matter.

[0059] In some implementations, the rapid cooling method employs positive pressure forced cooling.

[0060] Furthermore, embodiments of the present invention also provide the application of the metal-ceramic composite materials provided in any of the above embodiments in the fields of machining and oil drilling.

[0061] The technical solution of the present invention will be further described in detail below through several embodiments and in conjunction with the accompanying drawings. However, the selected embodiments are only for illustrating the present invention and do not limit the scope of the present invention.

[0062] Example 1

[0063] This embodiment provides a metal-ceramic composite material, the raw material mass fraction of which is as follows: 65wt% (Ti 0.94 Mo 0.06 )(C,N), 9 wt%TaC, 10 wt%WC, 8 wt%Co, 8 wt%Ni.

[0064] The preparation steps of the metal-ceramic composite material are as follows:

[0065] First, prepare (Ti) 0.94 Mo 0.06 (C,N) pre-alloyed powder was prepared by adding calculated amounts of TiO2, MoO3, and carbon powder into a sintering furnace. The mixture underwent a carbothermic reduction reaction at 1500 °C for 50 min under a nitrogen atmosphere. After complete reaction, the temperature was raised to 1850 °C for crystallization treatment. Finally, the mixture was cooled and pulverized to obtain (TiO2,N) pre-alloyed powder. 0.94 Mo 0.06 (C,N) pre-alloyed powder.

[0066] Based on the phase diagram, the C content was determined to be 1.5 wt%. Paraffin wax and Ti were then added in a specific ratio. 0.94 Mo 0.06(C,N) pre-alloyed powder, WC, TaC, Co, and Ni powder were placed in a cemented carbide ball mill jar, and anhydrous ethanol was added until the powder was completely wetted. The ball mill jar was then placed in a planetary ball mill with a ball-to-powder ratio of 10:1, a rotation speed of 350 r / min, and a milling time of 36 h. The milled slurry was then dried in a vacuum drying oven at 75 ℃ and sieved to obtain a dry mixed powder. Subsequently, it was pressed into shape at a pressure of 150 MPa and a holding time of 10 s, followed by vacuum sintering at a maximum sintering temperature of 1450 ℃ for 1.5 h. This was then followed by partial pressure sintering for 1.5 h at an argon pressure of 40 kPa. For cooling, positive pressure forced cooling was used, with a cooling rate of 150 ℃ / min to 200 ℃, followed by natural cooling.

[0067] In the above embodiments, the prepared (Ti) 0.94 Mo 0.06 The X-ray diffraction pattern of the (C,N) pre-alloyed powder is as follows: Figure 1 As shown, the characteristic peaks of the ceramic phase are shifted to the left compared to the characteristic peaks of Ti(C,N), indicating that Mo atoms are dissolved in Ti(C,N) and the solid solution effect is very complete, with no other characteristic peaks present.

[0068] Through such Figure 2 The backscattered electron microscopy (SEM) images of the metal-ceramic composite material show that the ceramic phase forms a complete ring structure with no exposed core phase (i.e., undissolved ceramic particles); while the transmission electron microscopy (TEM) images of the binder phase region are shown below. Figure 3 As shown, this indicates the presence of an amorphous / crystalline dual-phase structure in the binder region. X-ray diffraction of the crystalline phase region reveals a clear crystal diffraction spectrum, as shown below. Figure 4 As shown.

[0069] The hardness and fracture toughness of the metal-ceramic composite material provided in this embodiment were measured using a Vickers hardness tester. The hardness reached 1510 HV30, and the fracture toughness was 13.99 MPa·m. 1 / 2 .

[0070] Example 2

[0071] The preparation steps of the metal ceramic are as follows: (Ti) is obtained by using the same carbothermal reduction reaction and crystallization treatment. 0.88 W 0.12 (C,N) pre-alloyed powder, then with 70 wt% (Ti) 0.88 W 0.12A mixed powder was prepared by mixing 1 wt% carbon powder and a certain amount of forming agent according to the phase diagram. The powder was then placed in a cemented carbide ball mill jar and anhydrous ethanol was added until the powder was completely wetted. The ball mill jar was then placed in a planetary ball mill with a ball-to-powder ratio of 12:1, a rotation speed of 350 r / min, and a milling time of 40 h. The milled slurry was then dried in a vacuum drying oven at 75 ℃ and sieved to obtain a dry mixed powder. The material is pressed into shape at a pressure of 150 MPa, a holding time of 10 s, a maximum sintering temperature of 1500 ℃, and a vacuum sintering time of 2 h. Then, it is transferred to partial pressure sintering for 1.5 h with an argon pressure of 60 kPa. For cooling, positive pressure forced cooling is used at a cooling rate of 100 ℃ / min to below 200 ℃, and then it is allowed to cool naturally to room temperature.

[0072] The hardness and fracture toughness of the cermet were measured using a Vickers hardness tester. The hardness reached 1531 HV30, and the fracture toughness was 13.41 MPa·m. 1 / 2 Meanwhile, the microstructure characterization of the metal-ceramic composite material obtained in this embodiment also shows a clear complete core-ring structure and a two-phase structure in the metal binder phase.

[0073] Comparative Example 1

[0074] This comparative example is largely the same as Example 1, except that the raw materials used in the experiment were a ball-milled mixture of TiC-TiN and Mo2C, which was then sintered and crystallized to obtain TiC particles of the same size. 0.94 Mo 0.06 (C,N) powder was used to replace the pre-alloyed powder prepared by the carbothermic reduction reaction of oxides in Example 1, and the types and contents of elements were the same.

[0075] This resulted in the absence of a two-phase structure (crystalline and amorphous phases) in the binder region. The metal-ceramic composite material prepared in this comparative example was tested using the indentation method. The Vickers hardness of the composite material was 1499 HV30, and the fracture toughness was 11.9 MPa·m. 1 / 2 .

[0076] Comparative Example 2

[0077] The difference between this comparative example and Example 1 is that the original powder was generated by a carbothermal reaction, but no pre-alloying treatment above 1800°C was performed. The types and contents of elements are the same.

[0078] The morphology of the ceramic phase region was observed using scanning electron microscopy, and the results are as follows: Figure 5As shown, a core-ring structure that was not fully encapsulated was formed. The structure of the metal-bonded phase region was observed using transmission electron microscopy, and the results are as follows: Figure 6 As shown, the structure of the binder phase region is a single-phase amorphous structure, and the diffraction pattern of this amorphous structure is as follows. Figure 7 As shown.

[0079] This indicates that the ceramic phase and the binder phase are not independent during the preparation process, but rather have mutual influence. The lack of pre-alloying treatment not only affects the integrity of the core-ring structure of the ceramic phase, but also has a significant impact on whether the binder phase can form a two-phase structure.

[0080] The metal-ceramic composite material prepared in this comparative example was tested using the indentation method. The Vickers hardness of the metal-ceramic composite material was 1469 HV30, and the fracture toughness was 12.06 MPa·m. 1 / 2 .

[0081] Comparative Example 3

[0082] The difference between this comparative example and Example 1 is that commercial Ti(C,N) powder was directly used as the original powder, and crystallization treatment at 1800 °C or higher was also performed. However, the number of elements in the ceramic phase powder was reduced, lacking the refractory metal element Mo and failing to meet the requirement of having no less than eight elements.

[0083] The morphology of the ceramic phase region was observed using scanning electron microscopy, and the results are as follows: Figure 8 As shown, a core-ring structure that was not fully encapsulated was formed. The structure of the metal-bonded phase region was observed using transmission electron microscopy, and the results are as follows: Figure 9 As shown, the structure of the binder phase region is a single-phase crystalline structure, and the diffraction spectrum is as follows. Figure 10 As shown.

[0084] The metal-ceramic composite material prepared in this comparative example was tested using the indentation method. The Vickers hardness of the metal-ceramic composite material was 1437 HV30, and the fracture toughness was 12.05 MPa·m. 1 / 2 .

[0085] Comparative Example 4

[0086] The difference between this comparative example and Example 1 is that a drum ball mill was used instead of a high-energy ball mill to inject sufficient energy; all other conditions are the same.

[0087] The structure of the metal binder region was observed using transmission electron microscopy, and no amorphous / crystalline structures were found in the binder region. The metal-ceramic composite material prepared in this comparative example was tested using indentation. The Vickers hardness of the composite material was 1412 HV30, and the fracture toughness was 11.2 MPa·m.1 / 2 .

[0088] Comparative Example 5

[0089] The difference between this comparative example and Example 1 is that negative pressure forced cooling is used, reducing the cooling rate to 50 °C / min.

[0090] The structure of the metal binder region was observed using transmission electron microscopy. No amorphous / crystalline structures were observed in the binder region, which will not be elaborated further. The metal-ceramic composite material prepared in this comparative example was tested using the indentation method. The Vickers hardness of the composite material was 1405 HV30, and the fracture toughness was 11.5 MPa·m. 1 / 2 .

[0091] Comparative Example 6

[0092] Compared with Example 2, this comparative example reduced the number of second-type carbides, adding only one type of second-type carbide, TaC. The amount added was the sum of TaC and Mo2C in Example 2, i.e., 10 wt%. All other steps and conditions were the same. The metal-ceramic composite material prepared in this comparative example was tested using the indentation method. The Vickers hardness of the metal-ceramic composite material was 1349 HV30, and the fracture toughness was 11.58 MPa·m. 1 / 2 .

[0093] Using the same characterization methods, it was impossible to observe the complete core-ring structure in the ceramic phase and the two-phase structure in the metal-bonded phase.

[0094] Comparative Example 7

[0095] Compared with Example 2, this comparative example changed the type of the second ceramic phase and added a carbide with the same metal element as the pre-alloyed ceramic. Specifically, TaC was replaced with WC, and the remaining steps and parameters were the same.

[0096] The metal-ceramic composite material prepared in this comparative example was tested using the indentation method. The Vickers hardness of the metal-ceramic composite material was 1462 HV30, and the fracture toughness was 10.95 MPa·m. 1 / 2 .

[0097] Using the same scanning electron microscope, transmission electron microscope and X-ray diffraction characterization methods, the complete core ring structure could not be observed. Furthermore, due to the reduction in the number of elements, the two-phase structure could not be observed in the metal binder phase either.

[0098] Based on the above embodiments and comparative examples, it is clear that the preparation method provided in the embodiments of the present invention uses high-temperature carbothermal reaction and crystallization treatment of oxides and elemental carbon to prepare pre-alloyed ceramic powder (Ti,M)(C,N), which can lead to lattice distortion of the ceramic phase and improve the hardness of the ceramic phase. Subsequently, the pre-alloyed ceramic powder, metal binder phase powder, and second type of refractory metal carbide powder are mixed in a specific ratio, dried, pressed, and sintered using powder metallurgy to prepare a dense metal-ceramic composite material. By controlling the sintering process and setting the sintering-cooling window, the dissolution and crystallization processes of the metal-ceramic during liquid-phase sintering are controlled, achieving precise control of the ceramic phase core-ring structure, generating a complete core-ring structure, and realizing the phase structure evolution of the binder phase region to form an amorphous / crystalline dual-phase structure, ultimately achieving a synergistic improvement in the strength and toughness of the metal-ceramic composite material.

[0099] It should be understood that the above embodiments are merely illustrative of the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A cermet composite material with synergistically enhanced toughness, characterized in that, It includes a ceramic phase and a metal binder phase; the ceramic phase includes (Ti, M... a C(N) core phase, and (Ti,M) a C(N) and M b The solid solution ring phase formed by C, wherein the metallic binder phase comprises a crystalline phase and an amorphous phase; The solid solution ring phase completely encapsulates the core phase, so that the core phase does not come into contact with the metal bond phase; M a M is selected from any one or more combinations of refractory metal elements. b Combinations selected from two or more refractory metal elements, and M a and M b Non-overlapping; the metal binder phase includes two or more binder metal elements; the metal-ceramic composite material also contains residual oxygen elements, and the residual oxygen elements diffuse from the ceramic phase to the metal binder phase; (N) indicates selective inclusion or exclusion of N elements; and the total number of elements in the metal-ceramic composite material is eight or more. The metal-ceramic composite material, expressed as a composition, comprises: 55-70 wt% (Ti, M... a C(N) pre-alloyed powder, 10-25 wt% M b The pre-alloyed powder comprises: C-type carbide powder, 10-20 wt% metallic binder powder, and 0-2 wt% carbon powder; the remaining oxygen element accounts for 0.2-1.0 wt% of the pre-alloyed powder by mass ratio. M in the pre-alloyed powder a The atomic number is 0.03-0.12, and the (Ti,M) a The particle size of the C(N) pre-alloyed powder is less than 2 μm, M a Selected from any one or more combinations of W, Mo, Ta, Nb, V, Zr, and Cr, M b The metal binder phase is selected from two or more combinations of W, Mo, Ta, Nb, V, and Hf, and includes two or more combinations of Co, Ni, Fe, Mo, and Al.

2. The method of producing a cermet composite material as claimed in claim 1, characterized in that, include: Ti and M a are mixed with elemental carbon, and after a carbothermic reduction reaction, a crystallization treatment is performed at an elevated temperature to obtain (Ti, M a )C(N) pre-alloyed powder; The (Ti,M) was prepared by high-energy ball milling. a C(N) pre-alloyed powder and M b The second type of carbide powder, the metal binder phase powder, and the selectively added or unadded carbon powder were ball-milled to obtain a mixed powder. The mixed powder is pressed into shape and then subjected to vacuum sintering and partial pressure sintering in sequence. After sintering, the sintered product is rapidly cooled at a cooling rate of not less than 100℃ / min to obtain the metal-ceramic composite material.

3. The preparation method according to claim 2, characterized in that, The carbothermic reduction reaction is carried out at a temperature of 1400-1600 ℃ and the reaction time is less than 1 h; the crystallization treatment is carried out at a temperature of 1800-2200 ℃.

4. The production method according to claim 2, characterized by, The high-energy ball mill has a ball milling speed greater than 300 r / min, a ball milling time of not less than 24 h, and a ball-to-material ratio of 8:1-15:

1.

5. The preparation method according to claim 2, characterized in that, The vacuum sintering temperature is 1400-1500℃ and the time is 1-3 h; the partial pressure sintering temperature is 1400-1500℃, the pressure is 10-50 kPa, and the time is 1-3 h. The compression molding process uses a molding agent as an additive, with the amount of the molding agent added being 3-5 wt%. Furthermore, before the vacuum sintering, a degreasing sintering step is included to remove organic matter.

6. The preparation method according to claim 2, characterized in that, The rapid cooling method employs positive pressure forced cooling.

7. The application of the metal-ceramic composite material according to claim 1 in the fields of machining and oil drilling.

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