Double-phase compatible element modified metal ceramic and preparation process thereof

Abstract

The invention discloses a double-phase compatible element modified metal ceramic and a preparation process thereof, and relates to the field of powder metallurgy and hard materials.The preparation process comprises the following steps that S1, ceramic phase powder, metal binding phase powder and double-phase compatible element powder are mixed, and mixed powder is obtained; s2, carrying out wet ball milling on the mixed powder, drying, sieving or granulating to obtain a mixture; s3, pressing the mixture into a green body, and performing degumming treatment to obtain a degummed green body; and S4, the degummed blank is subjected to liquid-phase sintering at the temperature of 1300-1600 DEG C and cooled to the room temperature after heat preservation, and the double-phase compatible element modified metal ceramic is obtained. According to the preparation technology, a large amount of double-phase compatible elements are dissolved into a metal liquid phase in the liquid phase sintering stage and participate in dissolution, transportation and precipitation circulation, the filling efficiency of the metal liquid phase to pores is improved, and therefore the density of the metal ceramic is improved, and microstructure regulation and control and mechanical property improvement are both considered.

Description

Technical Field

[0001] This invention relates to the fields of powder metallurgy and hard materials technology, and in particular to a dual-phase compatible element modified cermet and its preparation process. Background Technology

[0002] Low-binder-phase cermets, such as low-binder-phase cemented carbides or Ti(C,N)-based cermets, possess irreplaceable and vital application value in the field of precision molds and cutting tools for high-temperature manufacturing due to their advantages such as high hardness, good hot hardness, and wear resistance. As modern manufacturing progresses towards higher precision, efficiency, and reliability, the performance requirements for molds and cutting tools are constantly increasing. Low-binder-phase cermets, with their excellent high-temperature stability and wear resistance, are widely used in high-temperature forming and machining of complex components in industries such as aerospace, automotive manufacturing, and precision machinery.

[0003] However, under conditions of low binder phase content, the volume fraction of the liquid metal phase is relatively small during liquid-phase sintering processes such as gas pressure sintering. This results in insufficient filling of the pores between ceramic phase particles by the liquid metal, leading to numerous residual pores and insufficient density within the material. Consequently, the strength, hardness, and toughness of the cermet are compromised, limiting its application under more demanding conditions. To densify cermets with low binder phase content, researchers often employ spark plasma sintering, hot pressing, and oscillating pressure sintering techniques. These techniques aim to induce the metal binder phase to fill the pores under high pressure, achieving a densification effect.

[0004] Currently, the main engineering preparation method for cermets is gas pressure sintering. This technique is characterized by a high degree of freedom in the shape and size of the sintered samples, facilitating high-volume production. However, the pressure in gas pressure sintering comes from an inert gas, primarily ranging from 2-10 MPa, which is significantly lower than high-pressure sintering techniques such as spark plasma sintering, hot pressing, and oscillating pressure sintering based on mechanical pressure. This makes it difficult to densify cermets with low binder phase content under gas pressure sintering conditions, thus compromising their strength and hardness.

[0005] Therefore, there is an urgent need for a modification strategy that can effectively improve the density of low-binder phase metal ceramics under conventional gas pressure sintering conditions. Summary of the Invention

[0006] This invention overcomes the shortcomings of the prior art and provides a dual-phase compatibility element modified metal ceramic and its preparation process, which enables the dual-phase compatibility element to dissolve in large quantities into the metal liquid phase during the liquid phase sintering stage and participate in the dissolution, transport and precipitation cycle, thereby improving the filling efficiency of the metal liquid phase in the pores, thus improving the density of the metal ceramic, and taking into account both microstructure control and mechanical property improvement.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: Firstly, the present invention provides a preparation process for dual-phase compatibility element-modified cermets, comprising the following steps:

[0008] S1. Mix ceramic phase powder, metal binder phase powder and two-phase compatible element powder to obtain mixed powder;

[0009] S2. Using anhydrous ethanol as the mixing medium, the mixed powder is wet ball-milled, and then dried, sieved or granulated to obtain the mixture.

[0010] S3. Press the mixture into a pre-defined shape, and degumme the pre-defined shape under vacuum or negative pressure to obtain a degummed pre-defined shape.

[0011] S4. The degummed green body is heated to 1300-1600 ℃ for liquid phase sintering under an inert gas protective atmosphere. After holding at the temperature, it is cooled to room temperature in an inert gas environment of 2-10 MPa to obtain a two-phase compatible element modified metal ceramic.

[0012] In a preferred embodiment of the present invention, in step S1, the ceramic phase powder is a transition metal carbide or a transition metal carbonitride powder.

[0013] In a preferred embodiment of the present invention, in step S1, the metal binder powder is either Co powder or Ni powder, or a mixture of them in different proportions.

[0014] In a preferred embodiment of the present invention, in step S1, the dual-phase compatible element powder is selected from one or more transition metal element powders selected from Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, and W.

[0015] In a preferred embodiment of the present invention, in step S1, the mixed powder, by mass fraction, has the following composition: 1-20 wt% metal binder phase, 0.5-10 wt% biphase compatible element content, and the balance being ceramic phase.

[0016] In a preferred embodiment of the present invention, in step S2, the parameters of the wet ball milling are: ball-to-material mass ratio of 5-15:1, ball milling speed of 50-100 r / min, and ball milling time of 12-48 h.

[0017] In a preferred embodiment of the present invention, in step S3, the temperature of the degumming treatment is 260-600°C.

[0018] In a preferred embodiment of the present invention, in step S4, the heat preservation time is 0.5-4 h.

[0019] In a preferred embodiment of the present invention, in step S4, the inert gas is one of helium, argon, or neon.

[0020] In a second aspect, the present invention provides a biphase compatible element modified metal ceramic prepared by any of the above preparation processes, comprising a ceramic phase, a metal binder phase, and a biphase compatible element; wherein the biphase compatible element dissolves in the liquid phase formed by the metal binder phase during sintering and participates in the dissolution-precipitation process of the ceramic phase.

[0021] This invention addresses the shortcomings of the prior art and has the following beneficial effects:

[0022] (1) This invention provides a dual-phase compatible element modified metal ceramic and its preparation process. By introducing dual-phase compatible elements into the low-binder metal ceramic system, the dual-phase compatible elements dissolve into the metal liquid phase in large quantities during the sintering process. This not only changes the chemical composition and physical properties of the liquid phase, but also broadens the dissolution, transport, precipitation and mass transfer channels mediated by the metal liquid phase. At the same time, its introduction disturbs the local stoichiometric balance of the ceramic phase, which can promote the dissolution of other components in the ceramic phase into the liquid phase. This improves the capillary filling efficiency and ability of the limited volume of metal liquid phase to fill the pores between ceramic particles, resulting in a significant reduction in the number of residual pores inside the material and a substantial improvement in overall density. Compared with the existing technology that has to rely on high-pressure technologies such as spark plasma sintering or hot pressing to solve the densification problem of low-binder phase, this invention can achieve a similar densification effect under the low-pressure environment of conventional gas pressure sintering. This allows the metal ceramic to achieve performance levels close to or reaching those of high-pressure sintered materials while maintaining the freedom of shape preparation.

[0023] (2) The addition of biphase compatible elements in this invention not only improves the density but also participates in the dynamic precipitation process of the ceramic phase. The biphase compatible elements dissolved in the liquid phase will partially precipitate to the surface or grain boundary of the ceramic phase during the cooling process. Their precipitation behavior can refine the ceramic grains and optimize the phase interface bonding state, thereby enhancing the bonding force between the ceramic phase and the metal phase. This will synergistically improve and enhance the comprehensive mechanical properties of the metal ceramic. Compared with the common defect of insufficient mechanical properties of existing low-bonding phase metal ceramics due to high porosity, this invention effectively strengthens the load-bearing capacity and crack propagation resistance of the material through simple composition design. This enables the metal ceramic to have more stable performance and longer service life under harsh working conditions such as high temperature, high stress or wear, effectively expanding its application potential in the field of high-precision processing.

[0024] (3) The modification strategy in this invention is fully compatible with the existing gas pressure sintering industrial preparation process. The process is highly versatile. The densification driving force comes from the chemical potential difference and mass transfer enhancement brought about by the introduction of two-phase compatible elements, rather than relying on the increase of external mechanical pressure. High density low-binder phase metal ceramic products can be successfully prepared in a standard gas pressure sintering furnace with only 2-10 MPa inert gas pressure. This invention does not require changing the core equipment and parameters of the existing mainstream production line, making the process easy to integrate and promote in the existing production system, greatly reducing the manufacturing cost of high performance low-binder phase metal ceramics, which is conducive to promoting the large-scale engineering application of such materials in the fields of cutting tools, molds, etc., and has important economic value and industrial significance. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention 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 the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a SEM image of the (Ti,V,Nb,Ta,W)(C,N)-3Ni-1Cr cermet prepared in Example 1 of this invention;

[0027] Figure 2 This is a SEM image of the (Ti,V,Nb,Ta,W)(C,N)-3Ni-2Cr cermet prepared in Example 2 of this invention;

[0028] Figure 3 This is a SEM image of the (Ti,V,Nb,Ta,W)C-1.5Co-1.5Ni-3Cr cermet prepared in Example 3 of this invention;

[0029] Figure 4 This is a SEM image of the (Ti,V,Nb,Ta,W)C-1Co-2Ni-4Cr cermet prepared in Example 4 of this invention;

[0030] Figure 5 This is a SEM image of the (Ti,V,Nb,Ta,W)C-2Co-1Ni-2Mo cermet prepared in Example 5 of this invention;

[0031] Figure 6 This is a SEM image of the (Ti,V,Nb,Ta,W)C-1.5Co-1.5Ni-4Mo cermet prepared in Example 6 of this invention;

[0032] Figure 7This is a SEM image of the (Ti,V,Nb,Ta,W)(C,N)-3Ni-6Mo cermet prepared in Example 7 of this invention;

[0033] Figure 8 This is a SEM image of the (Ti,V,Nb,Ta,W)(C,N)-3Ni-8Mo cermet prepared in Example 8 of this invention;

[0034] Figure 9 This is a SEM image of the (Ti,V,Nb,Ta,W)(C,N)-3Ni-0.75Ti cermet prepared in Example 9 of this invention;

[0035] Figure 10 This is a SEM image of the (Ti,V,Nb,Ta,W)(C,N)-3Ni-1.5Ti cermet prepared in Example 10 of this invention;

[0036] Figure 11 This is a SEM image of the (Ti,V,Nb,Ta,W)(C,N)-3Ni-2Zr cermet prepared in Example 11 of this invention;

[0037] Figure 12 This is a SEM image of the (Ti,V,Nb,Ta,W)(C,N)-3Ni-4Zr cermet prepared in Example 12 of this invention;

[0038] Figure 13 This is a SEM image of the (Ti,V,Nb,Ta,W)(C,N)-3Ni-6Zr cermet prepared in Example 13 of this invention;

[0039] Figure 14 This is a SEM image of the (Ti,V,Nb,Ta,W)(C,N)-3Ni cermet prepared in Comparative Example 1 of this invention. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] 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. Therefore, the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0042] like Figure 1 , Figure 2 and Figure 3 As shown, a preparation process for a two-phase compatible element-modified cermet includes the following steps:

[0043] S1. Mix ceramic phase powder, metal binder phase powder and two-phase compatible element powder to obtain mixed powder;

[0044] S2. Using anhydrous ethanol as the mixing medium, the mixed powder is wet ball-milled, and then dried, sieved or granulated to obtain the mixture.

[0045] S3. Press the mixture into a pre-defined shape, and degumme the pre-defined shape under vacuum or negative pressure to obtain a degummed pre-defined shape.

[0046] S4. The degummed green body is heated to 1300-1600 ℃ for liquid phase sintering under an inert gas protective atmosphere. After holding at the temperature, it is cooled to room temperature in an inert gas environment of 2-10 MPa to obtain a two-phase compatible element modified metal ceramic.

[0047] In some specific embodiments, in step S1, the ceramic phase powder is a transition metal carbide or a transition metal carbonitride powder.

[0048] In some specific embodiments, in step S1, the metal binder powder is either Co powder or Ni powder, or a mixture of them in different proportions.

[0049] In some specific embodiments, in step S1, the dual-phase compatible element powder is selected from one or more transition metal element powders selected from Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, and W.

[0050] In some specific embodiments, in step S1, the mixed powder is, by mass fraction, 1-20 wt% of metallic binder phase, 0.5-10 wt% of two-phase compatible element content, and the balance being ceramic phase.

[0051] In some specific implementations, in step S2, the parameters for wet ball milling are: ball-to-material mass ratio of 5-15:1, ball milling speed of 50-100 r / min, and ball milling time of 12-48 h.

[0052] In some specific implementations, the temperature of the degumming process in step S3 is 260-600 ℃.

[0053] In some specific implementations, the heat preservation time in step S4 is 0.5-4 hours.

[0054] In some specific embodiments, in step S4, the inert gas is one of helium, argon, or neon.

[0055] The present invention provides a dual-phase compatible element modified metal ceramic prepared by any of the above preparation processes, comprising a ceramic phase, a metal binder phase and a dual-phase compatible element; the dual-phase compatible element dissolves in the liquid phase formed by the metal binder phase during sintering and participates in the dissolution-precipitation process of the ceramic phase.

[0056] To further simplify and make the present invention achieve its objectives and effects, the present invention will be further illustrated in conjunction with the following specific embodiments and comparative examples, but the present invention is not limited to the scope of the embodiments described herein.

[0057] It should be noted that the raw materials, equipment, and reagents used in this invention can all be purchased from the market or obtained through existing preparation methods; the particle size of the raw materials (Ti,V,Nb,Ta,W)C and (Ti,V,Nb,Ta,W)(C,N) powders is 1 μm, and they are prepared in the laboratory; the particle size of the Cr, Zr, and Mo powders is 0.8 μm, and they are all purchased from the market.

[0058] Example 1:

[0059] In this embodiment, the preparation of 1 wt% Cr-modified low-binder phase metal ceramics includes the following steps:

[0060] S1. Weigh 96 g of high-entropy carbonitride ceramic powder, whose nominal composition is (Ti 0.2 V 0.2 Nb 0.2 Ta 0.2 W 0.2 (C) 0.9 N 0.1 ), 3 g of Ni powder was used as the metal binder phase, 1 g of Cr powder was weighed as the two-phase compatibility element, and they were mixed to obtain a mixed powder;

[0061] S2. Add the mixed powder into a ball mill jar, add 200 mL of anhydrous ethanol as the ball milling medium, and add 2 wt% of polyethylene glycol as a molding agent. Use cemented carbide grinding balls and control the ball-to-powder mass ratio to be 10:1. Place the ball mill jar on a ball mill and run it at 70 r / min for 24 h. After the ball milling is completed, take out the mixture obtained from the ball milling, dry it in a vacuum oven, crush it and pass it through a 40-mesh sieve to obtain the mixture.

[0062] S3. Take an appropriate amount of the mixture, place it in a mold, and press it into a long strip with dimensions of 30mm × 5mm × 5mm on a single-shaft press at a pressure of 200 MPa. Place it in a vacuum sintering furnace, and sinter it at a vacuum degree better than 1.0 × 10⁻⁶. -2Under the condition of Pa, the temperature was increased to 400 ℃ at a heating rate of 5 ℃ / min and held for 1 h to completely remove the polyethylene glycol molding agent and obtain a degummed preform.

[0063] S4. The degummed green body is filled with high-purity argon gas to atmospheric pressure, heated to 1400 ℃ at a heating rate of 10 ℃ / min, and held at this temperature for liquid phase sintering for 1 h. After the holding period, argon gas is immediately introduced into the furnace and the pressure is maintained at 5 MPa. Under this pressure environment, the sample is cooled to room temperature at a cooling rate of about 50 ℃ / min to obtain biphase compatible element modified metal ceramic.

[0064] Example 2:

[0065] This embodiment is basically the same as Embodiment 1, except that the content of the two-phase compatible elements is different. The specific steps of S1 are as follows: 95 g of high-entropy carbonitride ceramic powder is weighed, whose nominal composition is (Ti 0.2 V 0.2 Nb 0.2 Ta 0.2 W 0.2 (C) 0.9 N 0.1 3 g of Ni powder was used as the metal binder phase, and 2 g of Cr powder was weighed as the two-phase compatibility element and mixed to obtain a mixed powder.

[0066] Example 3:

[0067] This embodiment is basically the same as Embodiment 1, except that the content of the two-phase compatible elements is different. The specific steps of S1 are as follows: 94 g of high-entropy carbide ceramic powder is weighed, whose nominal composition is (Ti 0.2 V 0.2 Nb 0.2 Ta 0.2 W 0.2 1.5 g of C and Co powder and 1.5 g of Ni powder were used as the metal binder phase, and 3 g of Cr powder was weighed as the two-phase compatibility element and mixed to obtain a mixed powder.

[0068] Example 4:

[0069] This embodiment is basically the same as Embodiment 1, except that the content of the two-phase compatible elements is different. The specific steps of S1 are as follows: 93 g of high-entropy carbide ceramic powder is weighed, whose nominal composition is (Ti 0.2 V 0.2 Nb 0.2 Ta 0.2 W 0.2 1 g of C and Co powder and 2 g of Ni powder were used as the metal binder phase, and 4 g of Cr powder was weighed as the two-phase compatibility element and mixed to obtain a mixed powder.

[0070] Example 5:

[0071] In this embodiment, the preparation of 2 wt% Mo-modified low-binder phase metal ceramics includes the following steps:

[0072] S1. Weigh 95 g of high-entropy carbide ceramic powder, whose nominal composition is (Ti 0.2 V 0.2 Nb 0.2 Ta 0.2 W 0.2 2g of Co powder and 1g of Ni powder were used as the metal binder phase, and 2g of Mo powder was weighed as the two-phase compatibility element. The mixture was then mixed to obtain a mixed powder.

[0073] S2. Add the mixed powder into a ball mill jar, add 200 mL of anhydrous ethanol as the ball milling medium, and add 2 wt% of polyethylene glycol as a molding agent. Use cemented carbide grinding balls and control the ball-to-powder mass ratio to be 10:1. Place the ball mill jar on a ball mill and run it at 70 r / min for 24 h. After the ball milling is completed, take out the mixture obtained from the ball milling, dry it in a vacuum oven, crush it and pass it through a 40-mesh sieve to obtain the mixture.

[0074] S3. Take an appropriate amount of the mixture, place it in a mold, and press it into a long strip with dimensions of 30 mm × 5 mm × 5 mm on a single-shaft press at a pressure of 200 MPa. Place it in a vacuum sintering furnace, and sinter it at a vacuum degree better than 1.0 × 10⁻⁶. -2 Under the condition of Pa, the temperature was increased to 400 ℃ at a heating rate of 5 ℃ / min and held for 1 h to completely remove the polyethylene glycol molding agent and obtain a degummed preform.

[0075] S4. The degummed green body is filled with high-purity argon gas to atmospheric pressure, heated to 1600 ℃ at a heating rate of 10 ℃ / min, and held at this temperature for liquid phase sintering for 1 h. After the holding period, argon gas is immediately introduced into the furnace and the pressure is maintained at 5 MPa. Under this pressure environment, the sample is cooled to room temperature at a cooling rate of about 50 ℃ / min to obtain biphase compatible element modified metal ceramic.

[0076] It should be noted that when the Mo content is low, its effect on lowering the eutectic point of the system is limited, and a higher temperature (1600 ℃) is required to generate a sufficient quantity of fluid Ni-Mo liquid phase to initiate an effective dissolution-precipitation process.

[0077] Example 6:

[0078] This embodiment is basically the same as Embodiment 5, except that the content of the two-phase compatible elements is different. The specific steps of S1 are as follows: 93 g of high-entropy carbide ceramic powder is weighed, whose nominal composition is (Ti0.2 V 0.2 Nb 0.2 Ta 0.2 W 0.2 1.5 g of Co powder and 1.5 g of Ni powder were used as the metal binder phase, and 4 g of Mo powder was weighed as the two-phase compatibility element. The mixtures were then mixed to obtain a mixed powder.

[0079] It should be noted that as the Mo content increases, the eutectic temperature of the system decreases, and thus the liquid phase sintering temperature in step S4 is 1500 ℃.

[0080] Example 7:

[0081] This embodiment is basically the same as Embodiment 5, except that the content of the two-phase compatible elements is different. The specific steps of S1 are as follows: 91 g of high-entropy carbonitride ceramic powder is weighed, whose nominal composition is (Ti 0.2 V 0.2 Nb 0.2 Ta 0.2 W 0.2 (C) 0.9 N 0.1 3 g of Ni powder was used as the metal binder phase, and 6 g of Mo powder was weighed as the two-phase compatible element and mixed to obtain a mixed powder.

[0082] It should be noted that with the increase of Mo content, the liquid phase sintering temperature in step S4 is further reduced to 1300 ℃ in order to suppress certain high-temperature adverse reactions.

[0083] Example 8:

[0084] This embodiment is basically the same as Embodiment 5, except that the content of the two-phase compatible elements is different. The specific steps of S1 are as follows: 89 g of high-entropy carbonitride ceramic powder is weighed, whose nominal composition is (Ti 0.2 V 0.2 Nb 0.2 Ta 0.2 W 0.2 (C) 0.9 N 0.1 3 g of Ni powder was used as the metal binder phase, and 8 g of Mo powder was weighed as the two-phase compatible element and mixed to obtain a mixed powder.

[0085] It should be noted that as the Mo content increases, the eutectic temperature of the system decreases, and thus the liquid phase sintering temperature in step S4 is 1400 ℃.

[0086] Example 9:

[0087] In this embodiment, the preparation of 0.75 wt% Ti-modified low-binder phase metal ceramics includes the following steps:

[0088] S1. Weigh 96.25 g of high-entropy carbonitride ceramic powder, whose nominal composition is (Ti 0.2 V 0.2 Nb 0.2 Ta 0.2 W 0.2 (C) 0.9 N 0.1 ), 3 g of Ni powder was used as the metal binder phase, and 0.75 g of Ti powder was weighed as the two-phase compatibility element and mixed to obtain a mixed powder;

[0089] S2. Add the mixed powder into a ball mill jar, add 200 mL of anhydrous ethanol as the ball milling medium, and add 2 wt% of polyethylene glycol as a molding agent. Use cemented carbide grinding balls and control the ball-to-powder mass ratio to be 10:1. Place the ball mill jar on a ball mill and run it at 70 r / min for 24 h. After the ball milling is completed, take out the mixture obtained from the ball milling, dry it in a vacuum oven, crush it and pass it through a 40-mesh sieve to obtain the mixture.

[0090] S3. Take an appropriate amount of the mixture, place it in a mold, and press it into a long strip with dimensions of 30 mm × 5 mm × 5 mm on a single-shaft press at a pressure of 200 MPa. Place it in a vacuum sintering furnace, and sinter it at a vacuum degree better than 1.0 × 10⁻⁶. -2 Under the condition of Pa, the temperature was increased to 400 ℃ at a heating rate of 5 ℃ / min and held for 1 h to completely remove the polyethylene glycol molding agent and obtain a degummed preform.

[0091] S4. The degummed green body is filled with high-purity argon gas to atmospheric pressure, heated to 1450 ℃ at a heating rate of 10 ℃ / min, and held at this temperature for liquid phase sintering for 1 h. After the holding period, argon gas is immediately introduced into the furnace and the pressure is maintained at 5 MPa. Under this pressure environment, the sample is cooled to room temperature at a cooling rate of about 50 ℃ / min to obtain biphase compatible element modified metal ceramic.

[0092] It should be noted that Ti is extremely active and is a very strong carbonitride forming element. Its main mechanism of action, in addition to dissolving in the Ni liquid phase, is to promote the dissolution of other metal elements into the Ni liquid phase, thereby increasing the liquid phase sintering temperature in step S4 to 1450 ℃.

[0093] Example 10:

[0094] This embodiment is basically the same as Embodiment 9, except that the content of the two-phase compatible elements is different. The specific steps of S1 are as follows: 95.5 g of high-entropy carbonitride ceramic powder is weighed, whose nominal composition is (Ti 0.2 V 0.2 Nb 0.2 Ta 0.2 W0.2 (C) 0.9 N 0.1 3 g of Ni powder was used as the metal binder phase, and 1.5 g of Ti powder was weighed as the two-phase compatibility element and mixed to obtain a mixed powder.

[0095] Example 11:

[0096] In this embodiment, the preparation of 4 wt% Zr-modified low-binder phase metal ceramics includes the following steps:

[0097] S1. Weigh 93 g of high-entropy carbonitride ceramic powder, whose nominal composition is (Ti 0.2 V 0.2 Nb 0.2 Ta 0.2 W 0.2 (C) 0.9 N 0.1 ), 3 g of Ni powder was used as the metal binder phase, and 4 g of Zr powder was weighed as the two-phase compatibility element and mixed to obtain a mixed powder;

[0098] S2. Add the mixed powder into a ball mill jar, add 200 mL of anhydrous ethanol as the ball milling medium, and add 2 wt% of polyethylene glycol as a molding agent. Use cemented carbide grinding balls and control the ball-to-powder mass ratio to be 10:1. Place the ball mill jar on a ball mill and run it at 70 r / min for 24 h. After the ball milling is completed, take out the mixture obtained from the ball milling, dry it in a vacuum oven, crush it and pass it through a 40-mesh sieve to obtain the mixture.

[0099] S3. Take an appropriate amount of the mixture, place it in a mold, and press it into a long strip with dimensions of 30 mm × 5 mm × 5 mm on a single-shaft press at a pressure of 200 MPa. Place it in a vacuum sintering furnace, and sinter it at a vacuum degree better than 1.0 × 10⁻⁶. -2 Under the condition of Pa, the temperature was increased to 400 ℃ at a heating rate of 5 ℃ / min and held for 1 h to completely remove the polyethylene glycol molding agent and obtain a degummed preform.

[0100] S4. The degummed green body is filled with high-purity argon gas to atmospheric pressure, heated to 1400 ℃ at a heating rate of 10 ℃ / min, and held at this temperature for liquid phase sintering for 1 h. After the holding period, argon gas is immediately introduced into the furnace and the pressure is maintained at 5 MPa. Under this pressure environment, the sample is cooled to room temperature at a cooling rate of about 50 ℃ / min to obtain biphase compatible element modified metal ceramic.

[0101] Example 12:

[0102] This embodiment is basically the same as Embodiment 11, except that the content of the two-phase compatible elements is different. The specific steps of S1 are as follows: 91 g of high-entropy carbonitride ceramic powder is weighed, whose nominal composition is (Ti 0.2 V 0.2 Nb 0.2 Ta 0.2 W 0.2 (C) 0.9 N 0.1 Ni powder 3 g was used as the metal binder phase, and Zr powder 6 g was weighed as the two-phase compatibility element and mixed to obtain a mixed powder.

[0103] Example 13:

[0104] This embodiment is basically the same as Embodiment 11, except that the content of the two-phase compatible elements is different. The specific steps of S1 are as follows: 89 g of high-entropy carbonitride ceramic powder is weighed, whose nominal composition is (Ti 0.2 V 0.2 Nb 0.2 Ta 0.2 W 0.2 (C) 0.9 N 0.1 Ni powder 3 g was used as the metal binder phase, and Zr powder 8 g was weighed as the two-phase compatibility element and mixed to obtain a mixed powder.

[0105] Comparative Example 1:

[0106] In this comparative example, the preparation of unmodified HECN-3Ni low-binder phase cermet includes the following steps:

[0107] S1. Weigh 97 g of high-entropy carbonitride ceramic powder, whose nominal composition is (Ti 0.2 V 0.2 Nb 0.2 Ta 0.2 W 0.2 (C) 0.9 N 0.1 ), 3 g of Ni powder was used as the metal binder phase and mixed to obtain a mixed powder;

[0108] S2. Add the mixed powder into a ball mill jar, add 200 mL of anhydrous ethanol as the ball milling medium, and add 2 wt% of polyethylene glycol as a molding agent. Use cemented carbide grinding balls and control the ball-to-powder mass ratio to be 10:1. Place the ball mill jar on a ball mill and run it at 70 r / min for 24 h. After the ball milling is completed, take out the mixture obtained from the ball milling, dry it in a vacuum oven, crush it and pass it through a 40-mesh sieve to obtain the mixture.

[0109] S3. Take an appropriate amount of the mixture, place it in a mold, and press it into a long strip with dimensions of 30 mm × 5 mm × 5 mm on a single-shaft press at a pressure of 200 MPa. Place it in a vacuum sintering furnace, and sinter it at a vacuum degree better than 1.0 × 10⁻⁶. -2 Under the condition of Pa, the temperature was increased to 400 ℃ at a heating rate of 5 ℃ / min and held for 1 h to completely remove the polyethylene glycol molding agent and obtain a degummed preform.

[0110] S4. The degummed green body is filled with high-purity argon gas to atmospheric pressure, heated to 1400 ℃ at a heating rate of 10 ℃ / min, and held at this temperature for liquid phase sintering for 1 h. After the holding period, argon gas is immediately introduced into the furnace and the pressure is maintained at 5 MPa. Under this pressure environment, the sample is cooled to room temperature at a cooling rate of about 50 ℃ / min to obtain the metal ceramic.

[0111] Performance testing: The density of the 30 mm × 5 mm × 5 mm specimens obtained from Examples 1-13 and Comparative Example 1 was calculated using Archimedes' displacement method. The results are shown in [the table below]. Figure 1-14 As shown in the figure, the transverse fracture strength was tested at a strain rate of 0.2 mm / s, and the Vickers hardness was tested under a load of 10 kg for 15 s. The fracture toughness was calculated based on the hardness value and crack length. Seven sets of parallel tests were conducted for each property and their arithmetic mean was taken. The performance results are shown in Table 1.

[0112] Table 1:

[0113] project Density (%) Transverse fracture strength (MPa) Vickers hardness (GPa) <![CDATA[Fracture toughness (MPa·m 1 / 2 ).]]> Example 1 98.16 691.7±48.2 17.74±0.12 5.82±0.53 Example 2 98.89 572.2±42.2 18.17±0.12 5.63±0.42 Example 3 99.05 431.6±21.2 18.08±0.14 5.94±0.45 Example 4 99.36 548.4±27.2 17.96±0.17 5.72±0.37 Example 5 99.74 645.9±37.8 16.38±0.24 6.93±0.41 Example 6 99.73 689.7±33.6 17.24±0.37 5.62±0.26 Example 7 98.83 348.8±13.6 17.66±0.23 5.41±0.23 Example 8 98.10 512.2±16.7 17.91±0.31 5.23±0.42 Example 9 98.22 432.6±13.7 17.32±0.41 5.07±0.22 Example 10 98.36 463.7±15.3 17.44±0.35 5.23±0.31 Example 11 99.04 352.7±11.3 17.99±0.27 5.06±0.26 Example 12 97.26 313.6±12.5 18.88±0.36 5.62±0.39 Example 13 98.56 281.9±15.7 17.03±0.26 3.61±0.26 Comparative Example 1 93.55 446.1±47.3 16.08±0.32 5.51±0.43

[0114] As shown in Table 1:

[0115] The test data from Examples 1-13 fully verify the effectiveness of the proposed two-phase compatibilizer modification strategy in improving the overall performance of low-binder cermets. Compared with Comparative Example 1, which did not contain any two-phase compatibilizer, the density of all examples was significantly improved. A detailed analysis is provided below, based on the microstructures shown in the accompanying figures:

[0116] First, the most significant difference lies in the core indicator of packing density. Comparative Example 1 has a packing density of only 93.55%, and its corresponding microstructure is as follows: Figure 14 As shown, the presence of numerous residual pores within the material is the fundamental reason for its limited mechanical properties. In all examples with added biphasic compatibilizers, the density increased to over 97.26%, reaching a maximum of 99.74% (Example 5). This further confirms that the biphasic compatibilizer, by dissolving in the metallic binder phase (Ni) during the liquid-phase sintering stage, broadens the mass transport channels and enhances the capillary filling ability of the pores, thereby achieving near-complete densification under conventional gas pressure sintering conditions. Accordingly, as... Figures 1-13 As shown in the SEM images of each embodiment, the pore size and number inside the material are reduced, and the microstructure is more dense and uniform.

[0117] Secondly, there are optimization ranges for different two-phase compatible elements and their addition amounts. For Cr (Examples 1-4), as the addition amount increased from 1 wt% to 4 wt%, the density steadily increased from 98.16% to 99.36%. Figures 1-4 This indicates that within this range, Cr can effectively promote densification, with 4 wt% Cr showing the best effect. For Mo (Examples 5-8), both 2 wt% and 4 wt% additions achieved ultra-high densities exceeding 99.7%. Figure 5 , Figure 6 However, when the concentration was further increased to 6 wt% and 8 wt%, the density decreased slightly. Figure 7 , Figure 8 This may be related to the fact that excess Mo alters the properties of the liquid phase or leads to the precipitation of other phases. Ti and Zr elements also showed clear modifying effects. Figures 9-13 However, it is worth noting that while excessive Zr (Example 13, 8 wt%) maintained a high density, its fracture toughness decreased significantly to 3.61 MPa·m. 1 / 2 This may be due to the formation of a brittle phase or an adverse effect on interfacial bonding.

[0118] Furthermore, the increased density laid the structural foundation for improved mechanical properties. Overall, the Vickers hardness of the examples was generally higher than that of Comparative Example 1, directly related to the increased density. The changes in transverse fracture strength and fracture toughness were more complex, influenced not only by density but also by microstructure regulation such as grain refinement and changes in phase interface bonding caused by the addition of dual-phase compatible elements. For example, Example 5 (2 wt% Mo) achieved the highest density while also reaching the highest fracture toughness of 6.93 MPa·m among all samples. 1 / 2 This indicates that the addition of Mo not only promotes densification but also effectively optimizes the strength-toughness balance of the material. Figure 5 The corresponding microstructure also shows that its organization is uniform, which is beneficial to the improvement of performance.

[0119] In summary, the data in Table 1 and the appendix Figure 1-14 The microscopic evidence collectively demonstrates that by introducing specific types and amounts of biphase compatible elements, this invention can significantly improve the density of cermets under low binder phase and low-pressure sintering conditions, and simultaneously optimize their hardness, strength, and toughness. This achieves synergistic control over the microstructure and macroscopic properties of the material without altering existing industrial production equipment, and has significant engineering application value.

[0120] The above description is based on the preferred embodiments of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered exemplary and non-limiting in all respects. The scope of the invention is defined by the appended claims rather than the foregoing description, and all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0121] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A preparation process for dual-phase compatible element-modified cermets, characterized in that, Includes the following steps: S1. Mix ceramic phase powder, metal binder phase powder and two-phase compatible element powder to obtain mixed powder; S2. Using anhydrous ethanol as the mixing medium, the mixed powder is wet ball-milled, and then dried, sieved or granulated to obtain the mixture. S3. Press the mixture into a pre-defined shape, and degumme the pre-defined shape under vacuum or negative pressure to obtain a degummed pre-defined shape. S4. The degummed green body is heated to 1300-1600 ℃ for liquid phase sintering under an inert gas protective atmosphere. After holding at the temperature, it is cooled to room temperature in an inert gas environment of 2-10 MPa to obtain a two-phase compatible element modified metal ceramic.

2. The preparation process of a dual-phase compatible element-modified cermet according to claim 1, characterized in that: In step S1, the ceramic phase powder is a transition metal carbide or a transition metal carbonitride powder.

3. The preparation process of a dual-phase compatible element-modified cermet according to claim 1, characterized in that: In step S1, the metal binder powder is either Co powder or Ni powder, or a mixture of them in different proportions.

4. The preparation process of a dual-phase compatible element-modified cermet according to claim 1, characterized in that: In step S1, the dual-phase compatible element powder is selected from one or more transition metal element powders selected from Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, and W.

5. The preparation process of a dual-phase compatible element-modified cermet according to claim 1, characterized in that: In step S1, the mixed powder, by mass fraction, has the following composition: 1-20 wt% metallic binder phase, 0.5-10 wt% dual-phase compatible element content, and the balance being ceramic phase.

6. The preparation process of a dual-phase compatible element-modified cermet according to claim 1, characterized in that: In step S2, the parameters for wet ball milling are: ball-to-material mass ratio of 5-15:1, ball milling speed of 50-100 r / min, and ball milling time of 12-48 h.

7. The preparation process of a dual-phase compatible element-modified cermet according to claim 1, characterized in that: In step S3, the temperature of the degumming treatment is 200-600 ℃.

8. The preparation process of a dual-phase compatible element-modified cermet according to claim 1, characterized in that: In step S4, the heat preservation time is 0.5-4 h.

9. The preparation process of a dual-phase compatible element-modified cermet according to claim 1, characterized in that: In step S4, the inert gas is one of helium, argon, or neon.

10. A two-phase compatible element-modified cermet prepared by the preparation process described in any one of claims 1-9, characterized in that, It includes a ceramic phase, a metal binder phase, and a biphase compatible element; the biphase compatible element dissolves in the liquid phase formed by the metal binder phase during sintering and participates in the dissolution-precipitation process of the ceramic phase.

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