Thermal fatigue resistant ceramic tile cutting diamond saw blade and preparation process thereof

Abstract

This application relates to the field of diamond tool manufacturing technology, and discloses a heat-fatigue-resistant ceramic tile diamond saw blade and its preparation process. The heat-fatigue-resistant ceramic tile diamond saw blade includes a base steel disc and a diamond cutting head welded to its outer edge. The cutting head is made of a mixture comprising: a base matrix powder consisting of 40-50 parts of pre-alloyed copper-nickel alloy powder, 25-35 parts of elemental iron powder, 8-12 parts of elemental cobalt powder, and 13-17 parts of elemental tin powder; 5-10% Invar alloy powder, 1-3% elemental molybdenum powder, and 0.5-1.0% titanium hydride powder added according to the total weight of the base powder; and uncoated single-crystal diamond particles accounting for 15-25% of the total volume of the sintered cutting head. This invention uses a technical solution of pre-alloyed copper-nickel alloy powder combined with Invar alloy powder to adjust the matrix expansion rate, achieving the technical effect of reducing the alternating stress at the interface between diamond and metal binder.

Description

Technical Field

[0001] This invention relates to the field of diamond tool manufacturing technology, specifically to a thermal fatigue resistant ceramic brick diamond saw blade and its preparation process. Background Technology

[0002] Hard ceramic tiles are widely used in modern architecture and home decoration, and cutting these materials primarily relies on diamond saw blades. Cutting operations are typically accompanied by intense friction and heat generation. To cool the area and remove chips, cooling water must be continuously sprayed onto the cutting area during operation. This results in the working layer of the saw blade constantly undergoing alternating cycles of rapid heating and cooling. This unique operating condition places significant physical demands on the overall thermal stability of the saw blade's bonding material.

[0003] Most ceramic tile cutting saw blades on the market currently use conventional copper-iron-tin based metal binders, combined with diamond abrasives pre-plated with titanium or chromium, and then hot-pressed and sintered. This basic configuration offers acceptable processing efficiency under normal conditions. The metal matrix provides good rigidity and wear resistance, meeting the basic mechanical requirements for cutting hard ceramic tiles. The pre-coating technology improves the wetting of the diamond by the liquid metal under normal conditions. The binder and abrasive possess a certain initial bonding force under static conditions, enabling them to handle basic cutting tasks of moderate strength.

[0004] Existing technologies pose a risk of structural instability under alternating hot and cold operating conditions. The coefficient of thermal expansion of the metal matrix is ​​much greater than that of diamond. Frequent temperature fluctuations induce alternating shear stress at the interface between the two. Some solutions attempt to directly incorporate low-expansion Invar alloy to reduce deformation. However, in actual high-temperature copper-rich liquid-phase sintering, nickel atoms undergo cross-interface diffusion and dissolution. The original composition of the Invar alloy is disrupted, and its low-expansion properties are lost. Simultaneously, the pre-coated metal film has weak resistance to mechanical scratching. Diamond has sharp edges. Mixing and high-pressure cold pressing operations can cause the coating on the abrasive surface to peel off. During sintering, these damaged surfaces cannot form chemical bonds. Furthermore, traditional hot-pressing sintering uses a unidirectional cooling mechanism. During the cooling stage, the metal contracts rapidly, while the diamond size remains essentially unchanged. This inconsistent size contraction creates strong physical interference. A large amount of residual stress is forcibly trapped within the matrix. This leads to premature microcracks inside the cutting head, causing diamond particles to detach prematurely during subsequent cutting and heating. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a thermal fatigue resistant ceramic tile diamond saw blade and its manufacturing process. This addresses the problem that under alternating hot and cold cutting conditions, existing diamond saw blades are prone to thermal fatigue stress accumulation at the interface due to the mismatch in thermal expansion coefficients between the metal matrix and the superhard abrasive, leading to premature diamond particle detachment and ultimately shortening the actual cutting life of the saw blade.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] This invention provides the following technical solution:

[0008] In a first aspect, the present invention provides a thermal fatigue resistant diamond saw blade for cutting ceramic bricks, employing the following technical solution:

[0009] A thermal fatigue resistant diamond saw blade for cutting ceramic tiles includes a base steel disc and a diamond cutting head welded to the outer edge of the base steel disc; the diamond cutting head is prepared from a mixture containing the following components:

[0010] The base matrix powder is composed of the following components in parts by weight: 40-50 parts of pre-alloyed copper-nickel alloy powder, 25-35 parts of elemental iron powder, 8-12 parts of elemental cobalt powder, and 13-17 parts of elemental tin powder.

[0011] The added powder, by percentage of the total weight of the base carcass powder, includes the following components: 5-10% Invar alloy powder, 1-3% elemental molybdenum powder, and 0.5-1.0% titanium hydride powder;

[0012] Superhard abrasive: Uncoated single-crystal diamond particles, wherein the amount of uncoated single-crystal diamond particles added accounts for 15-25% of the total volume of the diamond cutting head after sintering.

[0013] By adopting the above technical solution, the pre-alloyed copper-nickel alloy powder combined with Invar alloy powder plays a role in regulating the thermal expansion and contraction of the metal matrix, while titanium hydride and elemental molybdenum powder induce a solid-state reaction at the interface, thereby alleviating the internal thermal stress and enhancing the matrix's holding strength for diamond.

[0014] Invar alloys have an extremely low coefficient of thermal expansion. Adding them to the matrix reduces the overall thermal deformation of the metal matrix and minimizes the difference in expansion coefficients between the matrix and diamond. However, under normal copper-rich liquid-phase sintering conditions, nickel atoms in the Invar alloy tend to dissolve into the low-nickel-concentration liquid phase, leading to compositional imbalance and loss of its low-expansion characteristics. Pre-introduced pre-alloyed copper-nickel alloy powder releases nickel around the Invar alloy particles during the initial liquid-phase formation, creating a similar concentration environment. This concentration balance counteracts the driving force of interfacial diffusion, preserving the internal structure of the Invar alloy and allowing it to act as a support point resisting deformation when the matrix is ​​subjected to thermal shock.

[0015] On the other hand, residual oxygen-containing groups often adhere to the surface of diamond, and the outer layer of elemental molybdenum powder often has a passivating oxide film. These factors hinder the direct reaction between carbon atoms and the metal. During sintering and heating, the titanium hydride powder in the system undergoes thermal decomposition: TiH2 → Ti + 2H. The released highly reactive primary hydrogen atoms can reduce the oxide layer on the surface of molybdenum powder and the oxygen atoms on the surface of diamond, thereby cleaning the reaction interface. At the same time, the decomposed primary titanium atoms, due to their strong affinity for carbon, preferentially aggregate and anchor on the diamond crystal surface, and promote the diffusion of surrounding molybdenum atoms to the diamond surface. Under high temperature conditions, titanium and molybdenum undergo interfacial solid-phase reactions with carbon on the diamond surface, respectively, to form a dense carbide transition layer: Ti + C → TiC; 2Mo + C → Mo2C. This carbide layer establishes chemical bonds between the abrasive and the binder, and together with the aforementioned low thermal expansion metal framework, jointly suppresses the generation and propagation of microcracks at the mechanical bonding surface.

[0016] Preferably, the proportions of the components in the mixture are as follows: 45 parts of pre-alloyed copper-nickel alloy powder, 30 parts of elemental iron powder, 10 parts of elemental cobalt powder, and 15 parts of elemental tin powder; 8% of Invar alloy powder, 2-3% of elemental molybdenum powder, and 0.5-0.8% of titanium hydride powder; the amount of uncoated single-crystal diamond particles added accounts for 20% of the total volume of the diamond cutting head after sintering.

[0017] By adopting the above technical solution, the specific component ratio takes into account both the hardness and impact resistance of the sintered matrix. Specifically, the content of certain metal components limits the amount of carbide produced at the interface, preventing excessive molybdenum powder from accumulating at grain boundaries and forming brittle zones. Furthermore, the specified amount of titanium hydride added is primarily to ensure that the initial hydrogen release is sufficient to reduce the metal oxides, thereby maintaining the conventional mechanical properties of the cutting tool and the bonding strength of the abrasive.

[0018] Preferably, the average particle size of the elemental iron powder is 10-20 μm; the average particle size of the elemental cobalt powder is 1-5 μm; the average particle size of the elemental tin powder is 20-40 μm; the average particle size of the elemental molybdenum powder is 1-3 μm; the average particle size of the titanium hydride powder is 5-10 μm; and the particle size of the uncoated single-crystal diamond particles is between 40 / 50 mesh and 50 / 60 mesh.

[0019] By adopting the above technical solution, a multi-size physical spatial distribution structure was established during the raw material preparation stage. Fine-grained elemental cobalt and molybdenum powders adhere more easily to the surface of coarse-grained diamond during mixing, directly shortening the interfacial diffusion path of active metal atoms at high temperatures. Meanwhile, the relatively large-grained elemental tin powder, due to its smaller specific surface area, delays the extensive penetration of the low-melting-point liquid phase into the matrix, thus preventing the liquid phase from prematurely encapsulating the molybdenum and titanium powders and ensuring the unobstructed flow of the solid-phase carbonization reaction channels.

[0020] Preferably, the pre-alloyed copper-nickel alloy powder is composed of copper and nickel in a mass ratio of 88-92:8-12, with an average particle size between 20-40 μm. The preparation method is as follows: pure copper and pure nickel are placed in a graphite crucible of an induction melting furnace and heated to 1350-1400℃ under argon protection to fully melt and alloy the pure copper and pure nickel and hold at that temperature for 15-25 minutes. Subsequently, the powder is prepared by vacuum atomization, with the atomizing gas pressure being high-purity nitrogen at 6-8 MPa. After collecting the powder, it is obtained by air classification and sieving.

[0021] By employing the above technical solution, the powder is rapidly cooled and shaped in a droplet state using a vacuum atomization process. This results in a relatively uniform elemental distribution within the pre-alloyed copper-nickel alloy powder, reducing segregation. By controlling the specific mass ratio of copper to nickel, the powder can release a nickel ion concentration matching the edge state of the Invar alloy during subsequent sintering, thereby maintaining a local equipotential environment and preventing the fatigue-resistant alloy powder from degrading at high temperatures.

[0022] Preferably, the Invar alloy powder is composed of iron, nickel, and metallic manganese, wherein the mass ratio of iron to nickel is 63-65:35-37, the amount of metallic manganese added accounts for 0.05-0.15% of the total melt mass, and the average particle size is between 20-30 μm; the preparation method is as follows: industrial pure iron and electrolytic nickel are placed in a vacuum induction melting furnace and melted and homogenized at 1500-1550℃, metallic manganese accounting for 0.05-0.15% of the total melt mass is added as a deoxidizing and desulfurizing agent and kept at the temperature for 10-20 minutes; the powder is cooled and powdered using a water-air combined atomization method, and the powder is collected, dried, and then screened by airflow.

[0023] By employing the above technical solution and utilizing the high cooling rate provided by the combined water-air atomization method, the Invar alloy powder retains the desired crystal structure. The addition of a small amount of metallic manganese as a deoxidizing and desulfurizing agent removes some impurities at grain boundaries, reducing intergranular fracture caused by impurity aggregation. The specific iron-nickel ratio ensures the material's low thermal expansion characteristics, enabling it to function stably under high-frequency thermal shock conditions.

[0024] Secondly, the present invention provides a manufacturing process for a diamond saw blade for cutting ceramic bricks resistant to thermal fatigue, employing the following technical solution:

[0025] A manufacturing process for a diamond saw blade for cutting ceramic bricks resistant to thermal fatigue includes the following steps:

[0026] S1. Weigh the base matrix powder and the added powder according to the ratio and mix them. Then add the uncoated single crystal diamond particles and spray in the molding agent and continue mixing to obtain the mixture.

[0027] S2. Place the mixture in the mold cavity, apply a unidirectional pressure of 200-300MPa at room temperature for cold pressing, hold the pressure for 10-20 seconds, and then demold to obtain the cold-pressed blank of the cutter head.

[0028] S3. The cold-pressed green blank is placed into a graphite mold and then placed in a hot pressing sintering furnace with atmosphere control function. Protective gas is introduced, and the following multi-stage hot pressing sintering process is carried out in sequence:

[0029] Dewaxing and heat preservation stage: Heat to 380-420℃, do not apply mechanical pressure and keep warm for 15-30 minutes;

[0030] Solid-phase activation stage: Heat to 630-670℃, apply axial pressure of 12-18MPa and hold for 25-40 minutes;

[0031] Liquid phase densification stage: Heat to 800-840℃, while increasing the axial pressure to 30-40MPa and holding the temperature and pressure for 10-20 minutes;

[0032] Isothermal annealing stage: Unload part of the axial pressure to 8-12MPa, slowly cool to 220-240℃, and perform isothermal pressure holding on this temperature platform for 35-55 minutes;

[0033] Finally, completely unload the mechanical pressure and cut off the heating power. After the furnace cools naturally to room temperature, demold the sintered diamond tool head and take it out.

[0034] S4. After grinding and removing rust from the bottom surface of the sintered diamond saw head, weld it to the outer edge of the circumference of the base steel disc, and then cut to obtain the finished saw blade.

[0035] By adopting the above technical solution, hot pressing sintering is divided into multiple temperature and pressure control zones, such as solid phase evolution, liquid phase densification, and annealing, which staggers the occurrence time of interfacial chemical bonding and matrix densification, and releases the internal stress of the material at the end of sintering.

[0036] During the solid-state activation stage at 630-670℃, the low-melting-point materials within the system have not yet melted on a large scale. Maintaining this temperature range prevents the premature appearance of a large amount of tin-rich liquid phase that could encapsulate the active metal particles, allowing the solid-state grain boundary network to continue serving as a channel for atomic diffusion. During this period, titanium and molybdenum atoms within the system diffuse to the diamond surface via the solid-state network, undergoing in-situ reactions of interfacial carbides. Applying a relatively low initial axial pressure at this time can promote the initial convergence of powder particles without compromising the porous framework, increasing the atomic contact area.

[0037] As the temperature is raised to 800-840℃, the densification process begins, and the axial pressure is simultaneously increased. The low-melting-point components transform into a liquid phase and rapidly penetrate the metal skeleton network to fill the pores. The high-pressure environment forces out excess gas, accelerates the alloying process of the matrix, and embeds the diamond particles and the newly formed carbide layer together in the binder system to ensure the density of the working layer of the cutting tool.

[0038] During the cooling period after sintering, because the thermal expansion coefficient of the metal matrix is ​​significantly greater than that of diamond, the shrinkage of the matrix causes physical interference with the minimal shrinkage of the diamond, leading to the accumulation of strong elastic strain energy and residual stress within the material. Therefore, this process incorporates an isothermal annealing stage at 220-240℃. This temperature range is close to the magnetic transition region of Invar alloys, and the metal matrix still retains a certain degree of microscopic plasticity. By applying a slight pressure of 8-12 MPa, slow plastic deformation is induced in the metal matrix surrounding the diamond, thereby dissipating the accumulated elastic strain energy. This treatment mitigates the residual stress inside the cutting tool and reduces the possibility of microcracks forming when the cutting tool faces alternating hot and cold temperatures in the future.

[0039] Preferably, in step S1, the base matrix powder and the added powder are placed in a three-dimensional mixer and dry-mixed in air at a speed of 30-50 r / min for 1.5-2.5 hours; the molding agent is liquid paraffin, and the amount of liquid paraffin added accounts for 1.0-2.0% of the total mass of the mixed powder. After adding diamond particles and liquid paraffin, mixing continues for 0.8-1.5 hours.

[0040] By adopting the above technical solution, this step-by-step mixing method can effectively alleviate the obvious stratification phenomenon caused by the difference in specific gravity between metal powder and diamond. During the secondary mixing process, liquid paraffin adheres to the particle surface and plays a certain internal lubricating role in the subsequent cold pressing, reducing the resistance of particle friction and promoting a uniform density distribution in all parts of the green body.

[0041] Preferably, in step S3, nitrogen gas or a nitrogen-hydrogen mixture is introduced into the hot-pressing sintering furnace as a protective gas.

[0042] By adopting the above technical solution, nitrogen gas is introduced into the high-temperature furnace cavity to establish a relatively stable inert environment, preventing external free oxygen from entering the mold. If a nitrogen-hydrogen mixture is used, an additional reducing medium can be provided in the early stage of the reaction, which helps to remove oxides from the powder surface more quickly, allowing the activation and diffusion reactions of metal atoms to proceed smoothly.

[0043] Preferably, in the multi-stage hot pressing sintering process of step S3, the temperature change rate of each stage is controlled as follows: the heating rate to the dewaxing and holding stage is 8-12℃ / min; the heating rate to the solid phase activation stage is 6-10℃ / min; the heating rate to the liquid phase densification stage is 10-15℃ / min; and the cooling rate to the isothermal annealing stage is 2-5℃ / min.

[0044] By adopting the above technical solution, the gradient temperature change rate is set to match the rhythm of physical changes within the system. Initially, a low heating rate is maintained to allow time for the liquid paraffin to evaporate, preventing a large amount of gas from instantly accumulating and cracking the green body. During the densification stage, the heating rate is accelerated to shorten the residence time of the liquid components, preventing excessive loss of the liquid phase from the gaps in the graphite mold under continuous pressure. The final stage uses a slow cooling rate of 2-5℃ / min to minimize the temperature difference between the sample surface and interior, preventing new thermal cracks caused by uneven shrinkage.

[0045] Preferably, in step S4, a high-frequency induction brazing process is used to weld the diamond cutting tip to the outer edge of the circumference of a base steel disc made of 65Mn or 30CrMo material.

[0046] By adopting the above technical solution, high-frequency induction brazing can rapidly concentrate heat in a localized area to complete the weld formation, significantly shortening the exposure time of the entire saw head in a high-temperature environment and preventing the Invar alloy and carbide layers inside the saw head from degrading due to prolonged heating. A steel disc made of 65Mn or 30CrMo is selected, considering its high yield strength, which allows it to maintain good structural rigidity when the saw blade is subjected to alternating loads at high speed.

[0047] This invention provides a thermal fatigue resistant ceramic brick cutting diamond saw blade and its manufacturing process. It has the following beneficial effects:

[0048] 1. This invention employs a technical solution of using pre-alloyed copper-nickel alloy powder in combination with Invar alloy powder to adjust the matrix expansion rate, achieving the technical effect of reducing the alternating stress at the diamond-metal binder interface. Compared with the existing technology of directly mixing low-expansion alloy powder into the matrix, this solves the problem of low-expansion characteristic failure caused by the outward diffusion and dissolution of alloying elements in the sintering liquid phase.

[0049] 2. This invention employs a technical solution of in-situ interfacial reaction via the thermal decomposition of titanium hydride and synergistic effect with elemental molybdenum powder. This directly generates a carbide transition layer between the abrasive and the substrate, achieving the technical effect of improving the chemical holding strength of diamond. Compared to the existing technology that directly uses pre-coated diamond, this solution overcomes the shortcomings of its surface coating, which is easily subject to mechanical scratches or even large-area peeling during powder dry mixing and cold pressing.

[0050] 3. This invention employs a hot-pressing sintering technique that combines independent pressure application in multiple temperature zones with micro-pressure isothermal annealing. This induces slight plastic deformation in the metal matrix during the cooling period, achieving the technical effect of relaxing the macroscopic residual stress field within the material. Compared to the conventional one-step heating, pressurization, and direct cooling technique in existing technologies, this invention overcomes the shortcomings of the former, which easily accumulates high-intensity residual stress and thus induces microcracks due to inconsistent internal and external cooling and shrinkage. Attached Figure Description

[0051] Figure 1 This is a comparative test result diagram of the average linear expansion coefficient of the sintered samples in the test examples of this invention.

[0052] Figure 2 This is a comparative test diagram showing the diffraction intensity of surface characteristic carbides on recycled diamonds in the test examples of this invention;

[0053] Figure 3 This is a comparison diagram of the test results for the macroscopic residual stress on the working surface of the cutting head in the test examples of this invention;

[0054] Figure 4 This is a comparison chart of the cutting life of the saw blades in the test examples of this invention under the cold and heat alternating cycle test;

[0055] Figure 5 This is a comparison chart of the test results for the early diamond shedding rate of the saw blade in the test examples of this invention. Detailed Implementation

[0056] The technical solutions in 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.

[0057] The main raw materials and reagents used in the following examples and comparative examples have the following sources and specifications. Reagents not specifically mentioned are all commercially available analytical grade or higher grade products.

[0058] Raw materials used for preparing alloy powders by induction melting include electrolytic copper with a purity greater than or equal to 99.9% (CAS No. 7440-50-8), electrolytic nickel with a purity greater than or equal to 99.9% (CAS No. 7440-02-0), industrial pure iron with a purity greater than or equal to 99.9% (CAS No. 7439-89-6), and metallic manganese with a purity greater than or equal to 99.5% (CAS No. 7439-96-5).

[0059] The matrix elemental powders used for direct mixing with metal binders include elemental iron powder prepared by hydrogen reduction with a purity greater than or equal to 99.5% (CAS No. 7439-89-6) and an average particle size between 10 and 20 μm; elemental cobalt powder with a purity greater than or equal to 99.8% (CAS No. 7440-48-4) and an average particle size between 1 and 5 μm; and elemental tin powder prepared by gas atomization with a purity greater than or equal to 99.5% (CAS No. 7440-31-5) and an average particle size between 20 and 40 μm.

[0060] The purity of elemental molybdenum powder is greater than or equal to 99.9% (CAS No. 7439-98-7), and the average particle size is between 1 and 3 μm.

[0061] The titanium hydride powder has a purity of ≥99.0% (CAS No. 7704-98-5), an average particle size between 5 and 10 μm, and a theoretical internal hydrogen content of ≥3.8 wt%.

[0062] The single-crystal diamond particles (CAS No. 7782-40-3) are industrial-grade superhard abrasives with no pre-coating treatment on the surface, and the particle size is between 40 / 50 mesh and 50 / 60 mesh.

[0063] Liquid paraffin (CAS No. 8012-95-1) is used as a molding agent in the cold pressing preforming process of powder.

[0064] Preparation Example 1:

[0065] This preparation example provides a method for preparing pre-alloyed copper-nickel alloy powder, including the following steps:

[0066] High-purity electrolytic copper sheets and electrolytic nickel sheets were weighed according to a copper-to-nickel mass ratio of 90:10 and placed in a graphite crucible in a medium-frequency induction melting furnace. The crucible was heated to 1380 degrees Celsius under argon protection to fully melt and alloy the copper, and held at that temperature for 20 minutes. Powdering was carried out using a vacuum atomization method with a high-purity nitrogen gas pressure set at 7 MPa. After collecting the powder, it was sieved by an air classifier to obtain spherical pre-alloyed powder with a particle size between 25 and 35 μm for later use.

[0067] Preparation Example 2:

[0068] This preparation example provides a method for preparing pre-alloyed copper-nickel alloy powder, including the following steps:

[0069] High-purity electrolytic copper sheets and electrolytic nickel sheets were weighed according to a copper-to-nickel mass ratio of 88:12 and placed in a graphite crucible in a medium-frequency induction melting furnace. The crucible was heated to 1400 degrees Celsius under argon protection to fully melt and alloy the copper, and held at that temperature for 15 minutes. Powdering was carried out using a vacuum atomization method with a high-purity nitrogen gas pressure of 6 MPa. After collecting the powder, it was sieved by an air classifier to obtain spherical pre-alloyed powder with a particle size between 35 and 40 μm for later use.

[0070] Preparation Example 3:

[0071] This preparation example provides a method for preparing pre-alloyed copper-nickel alloy powder, including the following steps:

[0072] High-purity electrolytic copper sheets and electrolytic nickel sheets were weighed according to a copper-to-nickel mass ratio of 92:8 and placed in a graphite crucible in a medium-frequency induction melting furnace. The crucible was heated to 1350 degrees Celsius under argon protection to fully melt and alloy the copper, and held at that temperature for 25 minutes. Powdering was carried out using a vacuum atomization method with a high-purity nitrogen gas pressure of 8 MPa. After collecting the powder, it was sieved by an air classifier to obtain spherical pre-alloyed powder with a particle size between 20 and 25 μm for later use.

[0073] Preparation Example 4:

[0074] This preparation example provides a method for preparing Invar alloy powder, including the following steps:

[0075] Industrial pure iron and electrolytic nickel were weighed according to an iron-to-nickel mass ratio of 64:36 and placed in a vacuum induction melting furnace. They were melted and homogenized at 1525 degrees Celsius. 0.1% of metallic manganese was added as a deoxidizing and desulfurizing agent and the mixture was kept at this temperature for 15 minutes. The mixture was then cooled and powdered using a water-air combined atomization method. The high-pressure water pressure was set to 15 MPa and the nitrogen pressure to 3 MPa. After the powder was collected, dried, and sieved by airflow, alloy powder with a particle size between 24 and 28 μm was selected for later use.

[0076] Preparation Example 5:

[0077] This preparation example provides a method for preparing Invar alloy powder, including the following steps:

[0078] Industrial pure iron and electrolytic nickel were weighed out according to a mass ratio of 65:35 and placed in a vacuum induction melting furnace. They were melted and homogenized at 1550 degrees Celsius. 0.05% of metallic manganese was added as a deoxidizing and desulfurizing agent and the mixture was kept at this temperature for 10 minutes. The mixture was cooled and powdered using a water-air combined atomization method. The high-pressure water pressure was set to 12 MPa and the nitrogen pressure to 2 MPa. After the powder was collected, dried, and sieved by airflow, alloy powder with a particle size between 28 and 30 μm was selected for later use.

[0079] Preparation Example 6:

[0080] This preparation example provides a method for preparing Invar alloy powder, including the following steps:

[0081] Industrial pure iron and electrolytic nickel were weighed according to a mass ratio of 63:37 and placed in a vacuum induction melting furnace. They were melted and homogenized at 1500 degrees Celsius. 0.15% of metallic manganese was added as a deoxidizing and desulfurizing agent and the mixture was kept at this temperature for 20 minutes. The mixture was cooled and powdered using a water-air combined atomization method. The high-pressure water pressure was set to 18 MPa and the nitrogen pressure to 4 MPa. After the powder was collected, dried, and sieved by airflow, alloy powder with a particle size between 20 and 24 μm was selected for later use.

[0082] Example 1:

[0083] This embodiment provides a thermal fatigue resistant ceramic brick cutting diamond saw blade and its preparation process, including the following steps:

[0084] S1. Weigh the base matrix powder according to the following weight percentages: 45 parts of the pre-alloyed copper-nickel alloy powder obtained in Preparation Example 1, 30 parts of elemental iron powder, 10 parts of elemental cobalt powder, and 15 parts of elemental tin powder. Weigh 8% of the Invar alloy powder obtained in Preparation Example 4, 2% of elemental molybdenum powder, and 0.8% of titanium hydride powder according to the following percentages of the total weight of the base matrix. Place the above metal binder powder in a three-dimensional mixer and dry mix at a speed of 40 r / min for 2 hours in an air environment. Then add 40 / 50 mesh uncoated single crystal diamond particles, the amount of which accounts for 20% of the total volume of the working layer after sintering. Spray liquid paraffin, accounting for 1.5% of the total mass of the mixed powder, and continue mixing for 1 hour to obtain the mixture.

[0085] S2. After accurately weighing the mixture, fill it into the steel mold cavity of the saw blade head of standard size. Apply unidirectional pressure of 250MPa using a four-column hydraulic press at room temperature and hold the pressure for 15 seconds before demolding to obtain the cold-pressed green blank of the blade head.

[0086] S3. The green blank is placed in a high-strength graphite mold and then placed in a hot-press sintering furnace with atmosphere control. Nitrogen gas with a purity of 99.99% is introduced as a protective gas. First, the temperature is raised to 400°C at a heating rate of 10°C / min, without applying mechanical pressure, and held for 20 minutes. Then, the temperature is raised to 650°C at a heating rate of 8°C / min, with an axial pressure of 15MPa applied and held for 30 minutes. Next, the temperature is raised to 820°C at a heating rate of 12°C / min, while the axial pressure is steadily increased to 35MPa and held for 15 minutes. After that, part of the axial pressure is released to 10MPa, and the temperature is slowly lowered to 230°C at a cooling rate of 3°C / min. Isothermal holding is performed at this temperature for 45 minutes. Finally, the mechanical pressure is completely released and the heating power is cut off. After the furnace cools naturally to room temperature, the sintering cutter head is demolded and removed.

[0087] S4. The bottom surface of the sintered cutter head is mechanically ground to remove rust. It is then welded to the outer edge of the 65Mn base steel disc using a high-frequency induction brazing process. Finally, it is sharpened by cutting with a silicon carbide grinding wheel on a sharpening machine.

[0088] Example 2:

[0089] This embodiment provides a thermal fatigue resistant ceramic brick cutting diamond saw blade and its preparation process, including the following steps:

[0090] S1. Weigh the base matrix powder according to the following weight percentages: 40 parts of the pre-alloyed copper-nickel alloy powder obtained in Preparation Example 3, 35 parts of elemental iron powder, 12 parts of elemental cobalt powder, and 13 parts of elemental tin powder. Weigh 5% of the Invar alloy powder obtained in Preparation Example 6, 1% of elemental molybdenum powder, and 0.5% of titanium hydride powder according to the following percentages of the total weight of the base matrix. Place the above metal binder powder in a three-dimensional mixer and dry mix at a speed of 30 r / min for 2.5 hours in an air environment. Then add 50 / 60 mesh uncoated single crystal diamond particles, the amount of which accounts for 15% of the total volume of the working layer after sintering. Spray liquid paraffin, accounting for 1.0% of the total mass of the mixed powder, and continue mixing for 1.5 hours to obtain the mixture.

[0091] S2. After accurately weighing the mixture, fill it into the steel mold cavity of the saw blade head of standard size. Apply unidirectional pressure of 200MPa using a four-column hydraulic press at room temperature and hold the pressure for 20 seconds before demolding to obtain the cold-pressed green blank of the blade head.

[0092] S3. The green blank is placed in a high-strength graphite mold and then placed in a hot-press sintering furnace with atmosphere control. A nitrogen-hydrogen mixture with a volume ratio of 95:5 is introduced as a protective gas. First, the temperature is raised to 380°C at a heating rate of 8°C / min, without applying mechanical pressure, and held for 30 minutes. Then, the temperature is raised to 630°C at a heating rate of 6°C / min, with an axial pressure of 12MPa applied and held for 40 minutes. Next, the temperature is raised to 800°C at a heating rate of 10°C / min, while the axial pressure is steadily increased to 30MPa and held for 20 minutes. After that, part of the axial pressure is released to 8MPa, and the temperature is slowly lowered to 220°C at a cooling rate of 2°C / min. Isothermal holding is performed at this temperature for 55 minutes. Finally, the mechanical pressure is completely released and the heating power is cut off. After the furnace cools naturally to room temperature, the sintering cutter head is demolded and removed.

[0093] S4. The bottom surface of the sintered cutter head is mechanically ground to remove rust. It is then welded to the outer edge of the 30CrMo base steel disc using a high-frequency induction brazing process. Finally, it is sharpened by cutting with a silicon carbide grinding wheel on a sharpening machine.

[0094] Example 3:

[0095] This embodiment provides a thermal fatigue resistant ceramic brick cutting diamond saw blade and its preparation process, including the following steps:

[0096] S1. Weigh the base matrix powder according to the following weight percentages: 50 parts of the pre-alloyed copper-nickel alloy powder obtained in Preparation Example 2, 25 parts of elemental iron powder, 8 parts of elemental cobalt powder, and 17 parts of elemental tin powder. Weigh 10% of the Invar alloy powder obtained in Preparation Example 5, 3% of elemental molybdenum powder, and 1.0% of titanium hydride powder according to the following percentages of the total weight of the base matrix. Place the above metal binder powder in a three-dimensional mixer and dry mix at a speed of 50 r / min for 1.5 hours in an air environment. Then add 40 / 50 mesh uncoated single crystal diamond particles, the amount of which accounts for 25% of the total volume of the working layer after sintering. Spray in liquid paraffin, accounting for 2.0% of the total mass of the mixed powder, and continue mixing for 0.8 hours to obtain the mixture.

[0097] S2. After accurately weighing the mixture, fill it into the steel mold cavity of the saw blade head of standard size. Apply unidirectional pressure of 300MPa using a four-column hydraulic press at room temperature and hold the pressure for 10 seconds before demolding to obtain the cold-pressed green blank of the blade head.

[0098] S3. The green blank is placed in a high-strength graphite mold and then placed in a hot-press sintering furnace with atmosphere control. Nitrogen gas with a purity of 99.99% is introduced as a protective gas. First, the temperature is raised to 420°C at a heating rate of 12°C / min, without applying mechanical pressure, and held for 15 minutes. Then, the temperature is raised to 670°C at a heating rate of 10°C / min, with an axial pressure of 18MPa applied and held for 25 minutes. Next, the temperature is raised to 840°C at a heating rate of 15°C / min, while the axial pressure is steadily increased to 40MPa and held for 10 minutes. After that, part of the axial pressure is released to 12MPa, and the temperature is slowly lowered to 240°C at a cooling rate of 5°C / min. Isothermal holding is performed at this temperature for 35 minutes. Finally, the mechanical pressure is completely released and the heating power is cut off. After the furnace cools naturally to room temperature, the sintering cutter head is demolded and removed.

[0099] S4. The bottom surface of the sintered cutter head is mechanically ground to remove rust. It is then welded to the outer edge of the 65Mn base steel disc using a high-frequency induction brazing process. Finally, it is sharpened by cutting with a silicon carbide grinding wheel on a sharpening machine.

[0100] Example 4:

[0101] This embodiment provides a thermal fatigue resistant ceramic brick cutting diamond saw blade and its preparation process, including the following steps:

[0102] S1. Weigh the base matrix powder according to the following weight percentages: 45 parts of the pre-alloyed copper-nickel alloy powder obtained in Preparation Example 1, 30 parts of elemental iron powder, 10 parts of elemental cobalt powder, and 15 parts of elemental tin powder. Weigh 8% of the Invar alloy powder obtained in Preparation Example 4, 3% of elemental molybdenum powder, and 0.5% of titanium hydride powder according to the following percentages of the total weight of the base matrix. Place the above metal binder powder in a three-dimensional mixer and dry mix at a speed of 40 r / min for 2 hours in an air environment. Then add 40 / 50 mesh uncoated single crystal diamond particles, the amount of which accounts for 20% of the total volume of the working layer after sintering. Spray liquid paraffin, accounting for 1.5% of the total mass of the mixed powder, and continue mixing for 1 hour to obtain the mixture.

[0103] S2. After accurately weighing the mixture, fill it into the steel mold cavity of the saw blade head of standard size. Apply unidirectional pressure of 250MPa using a four-column hydraulic press at room temperature and hold the pressure for 15 seconds before demolding to obtain the cold-pressed green blank of the blade head.

[0104] S3. The green blank is placed in a high-strength graphite mold and then placed in a hot-press sintering furnace with atmosphere control. Nitrogen gas with a purity of 99.99% is introduced as a protective gas. First, the temperature is raised to 400°C at a heating rate of 10°C / min, without applying mechanical pressure, and held for 20 minutes. Then, the temperature is raised to 650°C at a heating rate of 8°C / min, with an axial pressure of 15MPa applied and held for 30 minutes. Next, the temperature is raised to 820°C at a heating rate of 12°C / min, while the axial pressure is steadily increased to 35MPa and held for 15 minutes. After that, part of the axial pressure is released to 10MPa, and the temperature is slowly lowered to 230°C at a cooling rate of 3°C / min. Isothermal holding is performed at this temperature for 45 minutes. Finally, the mechanical pressure is completely released and the heating power is cut off. After the furnace cools naturally to room temperature, the sintering cutter head is demolded and removed.

[0105] S4. The bottom surface of the sintered cutter head is mechanically ground to remove rust. It is then welded to the outer edge of the 65Mn base steel disc using a high-frequency induction brazing process. Finally, it is sharpened by cutting with a silicon carbide grinding wheel on a sharpening machine.

[0106] Comparative Example 1:

[0107] Compared with Example 1, the difference is that 40.5 parts of elemental copper powder and 4.5 parts of elemental nickel powder are used in the base matrix powder. The two are mechanically mixed and replace 45 parts of pre-alloyed copper-nickel alloy powder by the same mass. All other aspects are the same.

[0108] Comparative Example 2:

[0109] The difference from Example 1 is that titanium hydride powder was not added to the metal binder powder, but all other aspects are the same.

[0110] Comparative Example 3:

[0111] Compared with Example 1, the difference is that in the S3 hot pressing sintering step, the second stage of solid-state heat preservation process is cancelled. That is, after heating to 400°C at 10°C / min and holding for dewaxing, the temperature is directly heated to 820°C at a heating rate of 12°C / min and 35MPa axial pressure is applied for heat preservation and pressure holding for 15 minutes. The subsequent cooling and isothermal creep steps remain unchanged, and the rest are the same.

[0112] Comparative Example 4:

[0113] Compared with Example 1, the difference is that in the S3 hot pressing sintering step, the fourth stage of isothermal annealing process is cancelled. That is, after the holding and pressing at 820°C, the mechanical pressure is completely unloaded and the furnace is naturally cooled to room temperature. All other aspects are the same.

[0114] Comparative Example 5:

[0115] Compared with Example 1, the difference is that: Invar alloy powder, elemental molybdenum powder and titanium hydride powder were not added to the metal binder powder; and in the S3 hot pressing sintering step, after dewaxing at 10℃ / min to 400℃, the temperature was directly raised to 820℃ and pressured at 35MPa for 15 minutes, and then the pressure was directly released and cooled to room temperature with the furnace, that is, the traditional single-stage liquid phase hot pressing sintering process was adopted, and the rest were the same.

[0116] Test Example 1:

[0117] Test objective: To verify the protective effect of pre-alloyed copper-nickel powder on the low expansion characteristics of Invar alloy during hot pressing and sintering.

[0118] Test steps:

[0119] 1. According to the basic matrix powder and added powder composition ratio set in Examples 1 to 4 and Comparative Examples 1 and 5, pure metal binder mixtures without single crystal diamond particles were prepared respectively. Then, cold pressing preforming and atmosphere hot pressing sintering were carried out in strict accordance with the process parameters recorded in each example and comparative example. After the sample was cooled and demolded in the furnace, it was processed by slow wire cutting into cylindrical standard expansion samples with a length of 25.0 mm and a diameter of 5.0 mm.

[0120] 2. Position each prepared sample horizontally inside the alumina sample test tube holder of the high-precision thermal expansion instrument. Fine-tune the quartz glass push rod to ensure that the detection end face of the displacement sensor establishes a stable and completely parallel physical contact with the force-bearing surface of the sample. Then, perform zero-point calibration of the test system and set the initial contact load of the push rod to 0.1N.

[0121] 3. Continuously purge the test chamber with protective argon gas of 99.99% purity. Set the temperature control program to continuously and stably heat the tube furnace from room temperature (25°C) to 600°C at a constant heating rate of 5°C per minute. The test equipment collects the minute thermally induced deformation displacement of the sample axial direction in real time within this operating range. After the cooling cycle is completed, extract the average linear expansion coefficient value in the range of 25°C to 600°C.

[0122] The test data is shown in Table 1.

[0123] Table 1: Test results of the average linear expansion coefficient of sintered samples from each embodiment and comparative example

[0124] Group <![CDATA[Coefficient of linear thermal expansion (10 -6 / °C)]]> Example 1 8.73 Example 2 9.14 Example 3 8.42 Example 4 8.68 Comparative Example 1 15.26 Comparative Example 5 18.31

[0125] Conclusion: Based on Table 1 and Figure 1 The data shows that the average linear expansion coefficients of Examples 1 to 4 remained consistently at a low level, compared to 18.31 × 10⁻⁶ for the conventional base carcass represented by Comparative Example 5. -6The expansion values ​​at / ℃ create a significant data discrepancy. Traditional copper-based or iron-copper-based binders are prone to large macroscopic volume fluctuations when cutting dense ceramic tiles due to drastic temperature changes. This high expansion property of the matrix material and the extremely low expansion of diamond particles create a natural physical-geometric mismatch, becoming the physical cause of microscopic thermal stress accumulation at the cutting edge and leading to damage. After introducing Invar alloy components and hot-pressing them under specific multi-stage processes, the overall matrix structure exhibits a strong tendency for macroscopic dimensional convergence.

[0126] Turning our attention to the data differences between Example 1 and Comparative Example 1, both are identical in terms of the absolute mass percentage of the metallic elements. However, Comparative Example 1, prepared using a simple mechanical mixing method of elemental copper and elemental nickel, showed a significant rebound in its final expansion value to 15.26 × 10⁻⁶. -6 / ℃. This directly confirms from a macroscopic physical and quantitative perspective that the mechanical mixing of elemental powders cannot quickly establish an effective thermodynamic equilibrium system in the early stage of high-temperature sintering liquid phase generation. As a result, the nickel atoms inherent in the Invar alloy particle lattice dissolve in large quantities into the copper-rich liquid phase on the periphery under the drive of a strong concentration gradient. The iron-nickel ratio that was originally strictly maintained at around 36% is irreversibly destroyed, causing the added alloy components to lose their intrinsic effect of offsetting thermal expansion and contraction.

[0127] Pre-alloyed copper-nickel powder exhibits an irreplaceable physicochemical barrier function during this sintering evolution stage. The specific concentration of nickel pre-existing in the high-temperature copper-rich liquid phase region constructs a similar chemical potential at the interface micro-region between the Invar alloy edge and the liquid matrix, significantly weakening the driving thermodynamic tendency of nickel atom diffusion across the interface. Effectively protected by this equipotential mechanism, the Invar alloy retains its original phase structure intact and acts as a network of rigid anchors maintaining microscopic volume stability during cooling, fundamentally mitigating the risk of interfacial fatigue fracture induced by rapid heating and cooling in actual operating conditions.

[0128] Test Example 2:

[0129] Test objective: To verify the promoting effect of specific catalytic reduction conditions and temperature step control on the formation of chemical bonds at the diamond interface.

[0130] Test steps:

[0131] 1. The diamond cutting tool samples hot-pressed and sintered in Example 1, Comparative Example 2 and Comparative Example 3 were collected. They were immersed in a mixed solution of concentrated hydrochloric acid and concentrated nitric acid at a temperature of 80°C and a volume ratio of 3:1. The environment was kept ventilated and the reaction was continued until the metal matrix structure was completely dissolved and decomposed.

[0132] 2. The granular solid mixture remaining at the bottom of the reaction vessel was subjected to multiple centrifugal washing with water and ultrasonic cleaning with anhydrous ethanol, and then placed in a vacuum drying oven and dried at 60°C for 5 hours to obtain a group of free single-crystal diamond particles with interfacial reaction products attached to the surface.

[0133] 3. Extract sufficient diamond particles from each group, spread them evenly in the groove of the glass sample stage and compact them. Use an X-ray diffractometer to continuously scan under a Cu-Kα radiation target, set the scanning angle range to 20° to 80° and the step size to 0.02°, and obtain complete powder diffraction patterns.

[0134] 4. Import the collected spectra into crystallographic data analysis software for smoothing and polynomial fitting to subtract background scattering, locate and calibrate the standard crystal plane diffraction peaks of Mo2C and TiC, and extract the relative diffraction intensity integral values ​​of the main strong peaks of each interface carbide through numerical integration calculation.

[0135] The test data is shown in Table 2.

[0136] Table 2: XRD relative diffraction integral intensity test results of diamond interface carbides recovered in each example and comparative example.

[0137] Group <![CDATA[Relative diffraction integrated intensity of Mo2C]]> TiC relative diffraction integral intensity Example 1 1348.6 327.4 Comparative Example 2 51.3 0.0 Comparative Example 3 243.8 62.1

[0138] Conclusion: Based on Table 2 and Figure 2 The data from Example 1 showed significant characteristic diffraction peaks for Mo2C and a certain amount of TiC, while Comparative Example 2, lacking titanium hydride, barely captured any effective carbide formation signal. Micron-sized molybdenum powder exhibits an oxide passivation layer on its surface in conventional powder metallurgy environments, and diamond particles are generally coated with oxygen-containing groups. Both of these factors struggle to overcome the high solid-state reaction energy barrier without the intervention of an external activating medium. Titanium hydride undergoes thermal decomposition during heating, continuously releasing free-state primary hydrogen atoms. These highly reactive hydrogen atoms construct an in-situ strongly reducing microenvironment, clearing oxide obstacles at the reaction interface.

[0139] Accompanying the precipitation of nascent titanium atoms, due to their strong affinity for carbon, pre-anchor on the diamond surface, significantly reducing the activation energy of molybdenum-carbon atom bonding as a catalytic medium. Observations of the test values ​​in Comparative Example 3 show that eliminating the solid-phase insulation step and directly and rapidly heating to the liquid-phase densification temperature results in a significant reduction in the amount of target carbide formed. Traditional single-stage high-temperature hot pressing processes cause the low-melting-point phase of the matrix component to transform into a large amount of tin-rich liquid phase in a short time. These liquid phases preferentially and completely encapsulate the active transition metal powder due to their wettability.

[0140] This isolation of the liquid phase space blocks the physical pathways for molybdenum atoms to accumulate and diffuse along grain boundaries to the diamond surface, causing the thermodynamically inclined carburization reaction to stall due to the obstructed kinetic path. The isothermal solid-phase evolution stage set in this scheme before the formation of a large amount of liquid phase effectively decouples the overlapping conflict between interfacial chemical bonding and matrix physical densification on a timescale, ensuring that the activated metal can smoothly migrate and combine within the solid-phase framework network, and establishing a high-strength metallurgical interface anchor between the binder and the abrasive.

[0141] Test Example 3:

[0142] Test objective: To verify the relaxation effect of Curie-point isothermal microplastic creep on the residual thermal stress on the working surface of the tool tip.

[0143] Test steps:

[0144] 1. Naturally cooled and demolded diamond cutting heads from Examples 1 to 4, Comparative Example 4 and Comparative Example 5 were extracted as test objects. The working surfaces of the cutting heads were wiped with anhydrous ethanol to remove surface impurities, and then fixed on the multi-functional sample stage of the X-ray residual stress measuring instrument.

[0145] 2. Cr-Kα target material was selected as the radiation source. The X-ray tube voltage was set to 30kV and the current to 8mA. A representative high diffraction intensity crystal plane inside the matrix was selected as the diffraction detection target surface. The collimator spot diameter was adjusted to 2mm to cover the test micro-area containing the binder around the diamond particles.

[0146] 3. According to sin 2 The ψ method sets the test parameters so that the angle ψ between the sample plane normal and the diffraction crystal plane normal is within the range of 0° to 45°. Five test points with unequal spacing are selected for continuous step scanning, and the specific diffraction peak position shift data corresponding to each ψ angle are recorded.

[0147] 4. Substitute the collected diffraction angles into the Bragg equation to calculate the rate of change of interplanar spacing. Combine the material's elastic modulus and Poisson's ratio and other macroscopic elastic constants to derive and calculate the specific value of macroscopic residual stress. Repeat the measurement in three different regions of each cutter head sample and take the arithmetic mean of the absolute values.

[0148] The test data is shown in Table 3.

[0149] Table 3: Macroscopic residual stress test results of the working surface of the cutter head in each embodiment and comparative example

[0150] Group Absolute value of macroscopic residual stress (MPa) Example 1 42.7 Example 2 48.3 Example 3 41.5 Example 4 44.8 Comparative Example 4 183.6 Comparative Example 5 221.4

[0151] Conclusion: Based on Table 3 and Figure 3The data shows that the absolute values ​​of macroscopic residual stress measured on the working surface of the shaped cutting head in Examples 1 to 4 are in a relatively low range. In contrast, Comparative Examples 4 and 5 have high levels of residual internal stress. During the cooling process from high temperature to room temperature, the metal matrix network and diamond particles in the powder metallurgy multiphase composite system have an objective gap due to the thermal expansion properties, resulting in spontaneous thermal contraction incoordination within the system.

[0152] Comparative Example 4 underwent depressurization and furnace cooling after the hot-pressing densification process. The continuous cooling process caused the matrix to be physically hindered by the rigid diamond framework during shrinkage, resulting in the elastic strain energy being frozen inside the material in the form of a high-stress field at the interface. In this scheme, an isothermal pressure-holding platform is constructed near the Curie temperature, activating the positive volume expansion effect of the Invar composition during the ferromagnetic ordering transformation process. These volume-constant alloy particles act as dispersed stress-bearing nodes in the shrinking matrix network.

[0153] When the system is at this temperature plateau, the low-melting-point solid solution phase inside the matrix maintains lattice mobility. Under the drive of an external pressure holding load, the metal matrix will undergo dislocation slip and micro-plastic deformation around these nodes. After the creep aging cycle, the elastic energy accumulated in the early cooling stage is converted into plastic dissipation work, and the disordered stress field inside tends to relax, blocking the mechanical initiation of microcracks at the diamond bonding interface.

[0154] Test Example 4:

[0155] Test objective: To verify the actual service life of saw blades in each group under extreme hot and cold alternating conditions.

[0156] Test steps:

[0157] 1. Obtain the finished diamond saw blades prepared in Examples 1 to 4 and Comparative Examples 1 to 5, and install and fix them one by one on a CNC automatic cutting platform with a spindle speed of 3500 rpm.

[0158] 2. Adjust the feed speed of the cutting platform to 1.5 meters / minute, use a dense vitrified ceramic tile with a thickness of 20 mm as the processing substrate, start the cutting program and run it in a pure dry cutting condition without coolant for 2 minutes, so that the cutting edge of the saw blade working layer heats up rapidly due to intense friction.

[0159] 3. At the 2-minute mark of dry cutting, instantly activate the high-pressure coolant spray system with a pressure of 0.5 MPa, so that the saw blade working surface under high temperature conditions undergoes wet cutting conditions of rapid cooling and contraction for 1 minute. Set the above 3-minute operation combination as a standard thermal fatigue failure cycle.

[0160] 4. Maintain continuous alternating operation of the cycle, the system continuously records the area of ​​the tile cut by the saw blade until the working layer of the saw blade is completely worn out or loses its cutting ability, causing the feed load to exceed the limit and the machine to stop. Verify and count the final total cutting life area.

[0161] The test data is shown in Table 4.

[0162] Table 4: Test results of total cutting area of ​​saw blades in each group under extreme thermal fatigue environment

[0163] Group Total cutting life area (square meters) Example 1 156.42 Example 2 161.87 Example 3 148.95 Example 4 154.33 Comparative Example 1 85.71 Comparative Example 2 76.49 Comparative Example 3 88.24 Comparative Example 4 94.18 Comparative Example 5 63.56

[0164] Conclusion: Based on Table 4 and Figure 4 The data shows that the example group exhibited significantly higher service tolerance than the conventional control group in extremely harsh thermal alternating destructive tests, with the total cutting area exceeding the macroscopic limit of 140 square meters. Under the severe service conditions of rapid internal heat accumulation in the working layer due to pure dry cutting followed by instantaneous high-pressure cooling, compared to Comparative Example 1, which suffered from a short lifespan due to a purely physical-mechanical hybrid approach, and Comparative Example 5, which used a conventional molding system, the composite network prepared using a specific thermodynamic multi-field linkage mechanism effectively suppressed the malignant accumulation of destructive alternating thermal stress.

[0165] The data feedback from Comparative Examples 2 and 3, which lack a microscopic interface reaction mechanism, reveals that simply maintaining macroscopic volume stability without strong covalent bond anchoring makes it difficult for abrasive particles to maintain stable residence in the metal-bonded bed when facing the combined erosion of high-frequency cutting shear and thermal fatigue impact. The in-situ carbide bonding layer generated at the diamond edge constructs a transition zone for interfacial load transfer, effectively compensating for physical interstitial defects at the lattice scale. This forms a closed-loop synergy at the mechanistic level with the microplastic creep annealing effect forcibly intervened in the Curie temperature region.

[0166] This solution achieves a deep time-series decoupling of the chemical solid-state evolution of the material's micro-interface with the coordinated deformation of the macro-phase boundaries. It successfully reconstructs a mechanically stable environment with low thermal expansion and near-relaxed residual stress in the boundary region, which is prone to microcrack initiation. The overall structure of the cutting head maintains the integrity of the multiphase system through hundreds of rapid heating and cooling cycles, fundamentally blocking the premature detachment of superhard abrasive due to interfacial fatigue failure. This results in a significant leap in the overall cutting volume of diamond tools in extreme application scenarios.

[0167] Test Example 5:

[0168] Test objective: To verify the macroscopic inhibitory effect of the multi-field synergistic mechanism of the present invention on the persistent problem of early thermal fatigue shedding of diamond particles.

[0169] Test steps:

[0170] 1. During the execution of the extreme hot and cold alternating cutting program described in Test Example 4, when each set of saw blades in Examples 1 to 4 and Comparative Examples 1 to 5 completes a cutting mileage node of exactly 50 meters, the operation of the CNC cutting platform is actively stopped and the corresponding saw blade is disassembled.

[0171] 2. Use anhydrous ethanol and an ultrasonic generator to perform a 15-minute deep cleaning of the saw blade's working surface to remove ceramic debris and coolant residue adhering to the blade head surface. After drying in a vacuum drying oven, place it on the test platform of a high-precision 3D laser profile scanner.

[0172] 3. Set the vertical and horizontal resolution of the scanner to the micrometer level, emit laser beams to perform array scanning on a standard 10 mm × 10 mm area on the outer periphery of the blade, and collect three-dimensional terrain elevation point cloud data of the diamond-bond interface without relying on the acquisition of any optical microscopic images.

[0173] 4. Import the acquired point cloud data into the elevation analysis algorithm module, set a specific height difference recognition threshold, and the system will automatically distinguish and count the number of normal diamond particles that are higher than the base plane and the number of pore-like pits that are lower than the base plane within a unit area. The percentage of early shedding rate is calculated by the ratio of the two.

[0174] The test data is shown in Table 5.

[0175] Table 5: Test results of early diamond loss rate of saw blades in each group at a specific cutting distance

[0176] Group Early shedding rate (%) Example 1 12.4 Example 2 11.8 Example 3 13.5 Example 4 12.9 Comparative Example 1 38.6 Comparative Example 2 45.2 Comparative Example 3 41.7 Comparative Example 4 34.5 Comparative Example 5 52.8

[0177] Conclusion: Based on Table 5 and Figure 5 The data shows that in Examples 1 to 4, the early shedding rate after undergoing a 50-meter rigorous alternating hot and cold cutting condition was suppressed to an extremely low level of less than 14%. In stark contrast, the structural failure rate of the baseline comparison example 5 was as high as 52.8%, with a large amount of abrasive detaching from the matrix before substantial mechanical wear occurred. Under the alternating attack of high-temperature cutting and quenching jet, the microscopic boundary region of the traditional binder network is subjected to extremely high-frequency contraction and expansion oscillations. The purely physical interfacial bonding force rapidly decays under this nonlinear shear fatigue, and microcracks spontaneously initiate deep within the pores and rapidly propagate along the grain boundaries.

[0178] Comparative Examples 1 and 4 recorded shedding rates of 38.6% and 34.5%, respectively, accurately reflecting the mechanical weight of phase structure stability and internal stress relaxation during the service life. The mechanical mixing of elemental powders not only failed to prevent the irreversible dissolution of nickel within the Invar alloy during the initial liquid-phase encapsulation, leading to the large-scale failure of the "rigid anchor points" with low expansion characteristics, but more critically, the absence of the Curie point isothermal creep process completely sealed the high-energy thermal stress accumulated during sintering phase transformation to room temperature. These stress fields, latent at the interface edges, instantly transformed into an endogenous driving force for tearing the encapsulation layer under the combined impact of external rapid cooling and heating. The thermodynamic equipotential micro-region constructed in this scheme, combined with a micro-plastic deformation dissipation mechanism, successfully established a mechanical buffer barrier around the diamond, characterized by hysteresis thermal shock and internal stress approaching zero.

[0179] Comparative Examples 2 and 3, despite stripping the key catalytic system, still couldn't escape the problem of premature particle detachment. Premature liquid phase encapsulation or the lack of a reducing and deoxygenating microenvironment fundamentally blocked the kinetic channel for transition metals to diffuse across the interface into the solid phase. The retention mechanism of the binder system for the superhard abrasive remained at a low-intensity mechanical interlocking level. Our proposed solution, through forced solid-phase activation aging before the formation of a large amount of liquid phase, drives the in-situ precipitated carbides to build covalent bridges with high intrinsic binding energy at the lattice scale. This deep metallurgical riveting effect, deeply intertwined with the low-expansion matrix mechanical buffer network, cuts off the physical evolution path of diamond particle detachment due to thermal fatigue.

[0180] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A diamond saw blade for cutting ceramic tiles with thermal fatigue resistance, characterized in that, It includes a base steel disk and a diamond cutting tip welded to the outer edge of the base steel disk; the diamond cutting tip is made of a mixture containing the following components: The base matrix powder is composed of the following components in parts by weight: 40-50 parts of pre-alloyed copper-nickel alloy powder, 25-35 parts of elemental iron powder, 8-12 parts of elemental cobalt powder, and 13-17 parts of elemental tin powder. The added powder, by percentage of the total weight of the base carcass powder, includes the following components: 5-10% Invar alloy powder, 1-3% elemental molybdenum powder, and 0.5-1.0% titanium hydride powder; Superhard abrasive: Uncoated single-crystal diamond particles, wherein the amount of uncoated single-crystal diamond particles added accounts for 15-25% of the total volume of the diamond cutting head after sintering.

2. The thermal fatigue resistant ceramic tile cutting diamond saw blade according to claim 1, characterized in that, The proportions of each component in the mixture are as follows: 45 parts of pre-alloyed copper-nickel alloy powder, 30 parts of elemental iron powder, 10 parts of elemental cobalt powder, and 15 parts of elemental tin powder; 8% of Invar alloy powder, 2-3% of elemental molybdenum powder, and 0.5-0.8% of titanium hydride powder; the amount of uncoated single-crystal diamond particles added accounts for 20% of the total volume of the diamond cutting head after sintering.

3. The thermal fatigue resistant ceramic tile cutting diamond saw blade according to claim 1, characterized in that, The average particle size of the elemental iron powder is 10-20 μm; the average particle size of the elemental cobalt powder is 1-5 μm; the average particle size of the elemental tin powder is 20-40 μm; the average particle size of the elemental molybdenum powder is 1-3 μm; the average particle size of the titanium hydride powder is 5-10 μm; and the particle size of the uncoated single-crystal diamond particles is between 40 / 50 mesh and 50 / 60 mesh.

4. The thermal fatigue resistant ceramic brick cutting diamond saw blade according to claim 1, characterized in that, The pre-alloyed copper-nickel alloy powder is composed of copper and nickel in a mass ratio of 88-92:8-12, with an average particle size between 20-40 μm. The preparation method is as follows: pure copper and pure nickel are placed in a graphite crucible of an induction melting furnace and heated to 1350-1400℃ under argon protection to fully melt and alloy the pure copper and pure nickel and hold at that temperature for 15-25 minutes; then, the powder is prepared by vacuum atomization, with the atomizing gas pressure set to 6-8 MPa of high-purity nitrogen. After collecting the powder, it is obtained by airflow classification and sieving.

5. The thermal fatigue resistant ceramic tile cutting diamond saw blade according to claim 1, characterized in that, The Invar alloy powder is composed of iron, nickel and metallic manganese, wherein the mass ratio of iron to nickel is 63-65:35-37, the amount of metallic manganese added accounts for 0.05-0.15% of the total melt mass, and the average particle size is between 20-30 μm. The preparation method is as follows: industrial pure iron and electrolytic nickel are placed in a vacuum induction melting furnace and melted and homogenized at 1500-1550℃. 0.05-0.15% of metallic manganese as a deoxidizing and desulfurizing agent is added and the mixture is kept at this temperature for 10-20 minutes. The powder is then cooled and pulverized using a water-air combined atomization method. The collected powder is dried and then sieved by airflow.

6. A manufacturing process for a thermal fatigue resistant ceramic brick cutting diamond saw blade as described in any one of claims 1-5, characterized in that, Includes the following steps: S1. Weigh the base matrix powder and the added powder according to the ratio and mix them. Then add the uncoated single crystal diamond particles and spray in the molding agent and continue mixing to obtain the mixture. S2. Place the mixture in the mold cavity, apply a unidirectional pressure of 200-300MPa at room temperature for cold pressing, hold the pressure for 10-20 seconds, and then demold to obtain a cold-pressed blank of the cutter head. S3. The cold-pressed green blank of the cutting head is loaded into a graphite mold and placed in a hot pressing sintering furnace with atmosphere control function. Protective gas is introduced, and the following multi-stage hot pressing sintering process is carried out in sequence: Dewaxing and heat preservation stage: Heat to 380-420℃, do not apply mechanical pressure and keep warm for 15-30 minutes; Solid-phase activation stage: Heat to 630-670℃, apply axial pressure of 12-18MPa and hold for 25-40 minutes; Liquid phase densification stage: Heat to 800-840℃, while increasing the axial pressure to 30-40MPa and holding the temperature and pressure for 10-20 minutes; Isothermal annealing stage: Unload part of the axial pressure to 8-12MPa, slowly cool to 220-240℃, and perform isothermal pressure holding on this temperature platform for 35-55 minutes; Finally, completely unload the mechanical pressure and cut off the heating power. After the furnace cools naturally to room temperature, demold the sintered diamond tool head and take it out. S4. After grinding and removing rust from the bottom surface of the sintered diamond saw head, weld it to the outer edge of the circumference of the base steel disc, and then cut and sharpen it to obtain the finished saw blade.

7. The preparation process of the diamond saw blade for cutting thermal fatigue-resistant ceramic bricks according to claim 6, characterized in that, In step S1, the base matrix powder and the added powder are placed in a three-dimensional mixer and dry-mixed in air at a speed of 30-50 r / min for 1.5-2.5 hours; the molding agent is liquid paraffin, and the amount of liquid paraffin added accounts for 1.0-2.0% of the total mass of the mixed powder. After adding diamond particles and liquid paraffin, mixing continues for 0.8-1.5 hours.

8. The preparation process of the diamond saw blade for cutting thermal fatigue-resistant ceramic bricks according to claim 6, characterized in that, In step S3, nitrogen or a nitrogen-hydrogen mixture is introduced into the hot-pressing sintering furnace as a protective gas.

9. The preparation process of the diamond saw blade for cutting thermal fatigue-resistant ceramic bricks according to claim 6, characterized in that, During the multi-stage hot pressing sintering process in step S3, the temperature change rate of each stage is controlled as follows: The heating rate to the dewaxing and holding stage is 8-12℃ / min; The heating rate to the solid-phase activation stage is 6-10℃ / min; The heating rate to the liquid phase densification stage is 10-15℃ / min; The cooling rate to the isothermal annealing stage is 2-5℃ / min.

10. The preparation process of the diamond saw blade for cutting thermal fatigue-resistant ceramic bricks according to claim 6, characterized in that, In step S4, the diamond cutting tip is welded to the outer edge of the circumference of a base steel disc made of 65Mn or 30CrMo material using a high-frequency induction brazing process.

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