A method for preparing high-strength, high-toughness and wear-resistant PcBN cutting tools by B4C-reinforced TiNbZrTa

Abstract

The present invention belongs to the field of superhard material manufacturing, and in particular relates to a method for preparing high-strength, high-toughness, and wear-resistant PcBN cutting tools by B4C-reinforced TiNbZrTa. The method comprises pre-treating 4μm-6μm cBN powder with acid and alkali, mixing it with 10μm TiNbZrTa powder and 2μm-4μm B4C powder in a suitable proportion, and then vacuum drying it. The mixture is then loaded into a synthetic mold and assembled into a synthetic block. The block is then placed in a six-sided top press, where it is subjected to high temperature and high pressure to prepare a PcBN blade blank. The PcBN cutting tool is then brazed with a WC alloy to prepare the PcBN cutting tool. The process of the present invention is simple, controllable, easy to operate, highly efficient, and low-cost, capable of meeting the needs of large-scale industrial production, and can significantly improve the life of the PcBN cutting tool. In particular, it exhibits excellent performance when processing difficult-to-process materials such as high-temperature alloys and cemented carbides.

Description

Technical Field

[0001] The invention belongs to the field of superhard material manufacturing, and in particular relates to a method for preparing a high-strength, high-toughness, and wear-resistant PcBN tool by using B4C reinforced TiNbZrTa. Background Art

[0002] In today's manufacturing industry, increasingly stringent requirements are being placed on the performance of cutting tool materials, especially in the areas of high-speed and high-precision machining. Polycrystalline cubic boron nitride (PcBN) not only has high hardness but also excellent thermal and chemical stability. It also does not react with ferrous materials at high temperatures, making it an ideal choice for machining ferrous materials. However, performance degradation persists in high-temperature and high-wear environments. This is primarily due to the weak bond strength between the binder and cubic boron nitride (cBN) in traditional PcBN tools. Furthermore, the binder itself does not meet the required strength, toughness, and wear resistance at high temperatures, limiting its application and efficiency. To address this issue, researchers have been seeking various methods to improve the performance of the binder itself and the bond between the binder and cBN, thereby enhancing the overall performance of PcBN tools and expanding their application areas.

[0003] Because the surface of cBN particles is smooth and the surface energy is high, the wettability with metal is poor, resulting in only weak physical bonding between cBN particles and metal binder, making the holding force between metal binder and cBN particles weak, and the strength and hardness of metal binder will decrease at high temperature, resulting in reduced performance of PcBN tools at high temperature.

[0004] High-entropy alloys (HEAs), also known as multi-component alloys, baseless alloys, concentrated solid solution alloys, and complex alloys, each containing an atomic content of 5% to 35% of each element, transcend the traditional design concept of alloys based on one or two metallic elements. They exhibit four key effects: thermodynamic high entropy, structural lattice distortion, dynamic hysteresis diffusion, and a "cocktail" effect in properties. They exhibit high strength, hardness, wear resistance, fracture toughness, excellent low-temperature performance and structural stability, and good corrosion and oxidation resistance. They are used in a variety of fields, including aerospace, automotive, electronics, nuclear and other military applications, medical devices, and energy conversion and storage. Among the numerous HEAs, the TiNbZrTa series is a particularly difficult-to-dissolve HEA.

[0005] Boron carbide (B4C), also known as black diamond, is an inorganic substance with the chemical formula B4C. It is usually a gray-black powder. It is one of the three hardest known materials (after diamond and cubic boron nitride) and is used in tank armor, bulletproof vests and many industrial applications. B4C has the following specific performance characteristics: (1) High hardness: Its Mohs hardness is about 9.5, second only to diamond, making it suitable for manufacturing wear-resistant materials; (2) High strength: Its compressive strength and flexural strength are very high, making it suitable for high-stress environments; (3) Low density: Compared with other common shielding materials, B4C has a lower density, making it easier to transport and install; (4) Good neutron absorption capacity: B4C has a significant shielding effect on fast neutrons and is often used in nuclear reactors and radiation protection; (5) High-temperature stability: B4C can still maintain good performance at high temperatures and is suitable for high-temperature working environments; (6) Anti-oxidation: B4C has good anti-oxidation properties and can be used in harsh environments; (7) Corrosion resistance: B4C performs well in corrosive media such as acids and alkalis and has good chemical stability. Because of the above excellent properties, boron carbide is widely used in military industry, nuclear industry, engineering and other fields.

[0006] However, in the prior art, there is no method for preparing high-strength, high-toughness and wear-resistant PcBN cutting tools using ultrafine B4C and TiNbZrTa. Summary of the Invention

[0007] The purpose of the present invention is to provide a method for preparing high-strength, high-toughness and wear-resistant PcBN tools by reinforcing TiNbZrTa with B4C. By adding B4C as a reinforcing material to PcBN prepared with TiNbZrTa as a binder, the overall performance of PcBN is significantly improved, thereby preparing high-strength, high-toughness and wear-resistant PcBN tools, so that PcBN tools can adapt to more stringent processing conditions and meet the needs of modern manufacturing for high-performance tools.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] A method for preparing a high-strength, high-toughness, and wear-resistant PcBN tool by using B4C-reinforced TiNbZrTa, characterized by comprising the following steps:

[0010] S1. Select raw materials, which include the following components by mass percentage: 80%-85% main crystal phase, 13%-19.5% binder, and 0.5%-2.0% reinforcing agent; wherein the main crystal phase is cBN powder, the binder is TiNbZrTa powder, and the reinforcing agent is B4C powder;

[0011] S2. Mixing: adding the main crystal phase, binder and reinforcing agent to the solvent in proportion and mixing evenly to obtain a mixed slurry. The obtained mixed slurry is placed in a vacuum drying oven for drying and high-temperature treatment to obtain a mixed powder;

[0012] S3, sintering, filling the mixed powder into a synthesis mold to form a synthesis block, and performing high temperature and high pressure sintering in a six-sided top press according to the set process parameters. After unloading and cooling to room temperature, the PCBN sample is taken out;

[0013] S4. Brazing the PcBN sample sintered at high temperature and high pressure with the WC alloy substrate to obtain a PcBN tool.

[0014] Preferably, the cBN powder has a grain size of 4 μm-6 μm and a purity of 99.9%.

[0015] Preferably, the TiNbZrTa powder has a grain size of 10 μm and a purity of 99.9%.

[0016] Preferably, the B4C powder has a grain size of 2 μm-4 μm and a purity of 99.9%.

[0017] Preferably, in step S1, the cBN powder is first placed in a 10% to 30% dilute hydrochloric acid solution, boiled for 10 min to 50 min, and then washed with distilled water. The powder is then placed in a 10% to 30% NaOH solution, boiled for 10 min to 50 min, and then washed with distilled water. After centrifugation, the powder is first washed with distilled water, then washed with anhydrous ethanol, and finally vacuum dried for use.

[0018] Preferably, in step S2, a ball mill is used for mixing, and the weight ratio of the solvent, raw materials, and grinding balls in the ball mill is 2:1:3, the mixing time is 24h to 30h, and the grinding balls are zirconia balls or cemented carbide balls.

[0019] Preferably, in step S2, the solvent is anhydrous ethanol.

[0020] Preferably, in step S2, the drying is carried out at 3.0×10 -3 The samples were dried under vacuum at 60°C for 24 h.

[0021] Preferably, in step S2, the high temperature treatment is carried out at 3.0×10 -3 Pa in a vacuum environment and at a temperature of 500°C-600°C for 1h-3h.

[0022] Preferably, the process parameters of the high temperature and high pressure sintering in step S3 are: sintering pressure of 5-6 GPa, sintering temperature of 1450° C.-1550° C., and holding time of 5 min-10 min.

[0023] The present invention also includes other steps that enable its normal use, which are all conventional technical means in the field; in addition, the steps not limited in the present invention all adopt conventional means in the field and will not be described in detail here.

[0024] The working principle of the present invention is:

[0025] The present invention uses high-entropy alloy TiNbZrTa powder instead of general metal binders. During the high-temperature and high-pressure preparation process of PcBN cutting tools, components in TiNbZrTa react with B and N atoms in cBN to generate TiB2, ZrN, TiN, TaN, and Nb2B3, respectively. These reaction products have high hardness, strength, oxidation resistance, wear resistance, and corrosion resistance. Moreover, since these elements chemically react with B and N atoms in cBN during the preparation process, the bond between cBN and the binder is a chemical bond. The chemical bond energy is relatively high, resulting in a higher bonding force between cBN and the binder, which can improve the overall performance of the PcBN cutting tool.

[0026] The invention uses fine grains to improve the material's strength, hardness, and toughness. The 10μm TiNbZrTa powder and 4μm-6μm cBN powder not only increase the strength of the binder itself and the bond between the binder and cBN, but also improve the toughness of the PcBN tool, enhancing its overall performance.

[0027] The B4C powder used in the present invention has excellent wear resistance and corrosion resistance. When added as a reinforcing material to PcBN prepared with TiNbZrTa powder as a binder, it can significantly improve the overall performance of PcBN, thereby preparing high-strength, high-toughness, ultra-hard and wear-resistant PcBN tools, enabling PcBN tools to adapt to more demanding processing conditions and meet the needs of modern manufacturing for high-performance tools.

[0028] When the above materials are sintered in appropriate proportions and with suitable high temperature and high pressure processes, high strength, high toughness and wear resistance of cBN itself, high strength, high toughness, wear resistance and corrosion resistance of TiNbZrTa, and high temperature and high pressure processes are utilized, high strength, high toughness, wear resistance and corrosion resistance of B4C can be obtained by selecting appropriate high temperature and high pressure processes.

[0029] The beneficial effects of the present invention are:

[0030] The process of the present invention is simple, controllable, easy to operate, highly efficient, and low-cost, capable of meeting the requirements of large-scale industrial production. It utilizes the high hardness of cBN itself, the high strength, high hardness, and high fracture toughness of TiNbZrTa, and the high hardness, high strength, low density, high-temperature stability, and good oxidation resistance of B4C. Furthermore, the elements in TiNbZrTa react with the B and N atoms in cBN to form TiB2, ZrN, TiN, TaN, and Nb2B3, respectively. These nitrides and borides have high hardness, strength, and wear resistance. Furthermore, due to the chemical reaction under high temperature and high pressure, the bond between cBN and TiNbZrTa is transformed into a chemical bond, resulting in a high bonding strength between cBN and the binder. This improves the overall performance of PcBN tools, thereby significantly increasing the tool life, and exhibits excellent performance when machining difficult-to-machine materials such as high-temperature alloys and cemented carbides. DETAILED DESCRIPTION

[0031] The present invention is further described below with reference to specific examples. The illustrative embodiments and descriptions of the present invention are intended to explain the present invention but are not intended to limit the present invention. Based on the embodiments of the present invention, any modifications, equivalent substitutions, improvements, etc. made by those skilled in the art without creative work based on all other embodiments obtained in the present invention shall be included within the scope of protection of the present invention.

[0032] All raw materials of the present invention are not particularly limited in their sources and can be purchased from the market or prepared according to conventional methods well known to those skilled in the art.

[0033] The devices used in the present invention are not particularly limited and can be devices commonly used in the art.

[0034] Example 1

[0035] A method for preparing a high-strength, high-toughness, and wear-resistant PcBN tool by using B4C-reinforced TiNbZrTa, comprising the following steps:

[0036] S1. Select raw materials, which include the following components by mass percentage: 85% main crystalline phase, 14% binder, and 1% reinforcing agent. The main crystalline phase is cBN powder with a grain size of 4 μm to 6 μm and a purity of 99.9%. The binder is TiNbZrTa powder with a grain size of 10 μm and a purity of 99.9%. The reinforcing agent is B4C powder with a grain size of 2 μm to 4 μm and a purity of 99.9%.

[0037] In this embodiment, cBN powder was purchased from Zhengzhou Zhongnan Jet Superhard Materials Co., Ltd., model CBNM-W, TiNbZrTa powder was purchased from Beijing New Materials Research Institute, and B4C powder was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0038] S2. Mixing: adding the main crystal phase, binder and reinforcing agent to the solvent in proportion and mixing evenly to obtain a mixed slurry. The obtained mixed slurry is placed in a vacuum drying oven for drying and high-temperature treatment to obtain a mixed powder;

[0039] S3, sintering, filling the mixed powder into a synthesis mold to form a synthesis block, and performing high temperature and high pressure sintering in a six-sided top press according to the set process parameters. After unloading and cooling to room temperature, the PCBN sample is taken out;

[0040] S4. Brazing the PcBN sample sintered at high temperature and high pressure with the WC alloy substrate to obtain a PcBN tool.

[0041] In step S1, the cBN powder is first placed in a 30% dilute hydrochloric acid solution, boiled for 30 minutes, and then washed with distilled water. The powder is then placed in a 30% NaOH solution, boiled for 30 minutes, and washed with distilled water. After centrifugation, the powder is first washed with distilled water, then washed with anhydrous ethanol, and finally vacuum dried for use.

[0042] In step S2, a high-energy ball mill is used for mixing, with a rotation speed of 300 r / min and a mixing time of 24 h. In the high-energy ball mill, the weight ratio of solvent, raw material, and grinding ball is 2:1:3, and the grinding ball is zirconia ball. The solvent is anhydrous ethanol. The drying is carried out at 3.0×10 -3 Pa vacuum, 60 ° C temperature vacuum drying for 24h. The high temperature treatment was carried out at 3.0 × 10 -3 Pa in a vacuum environment and treated at 500°C for 3h.

[0043] The process parameters of the high temperature and high pressure sintering in step S3 are: sintering pressure of 5.0 GPa, sintering temperature of 1450°C, and holding time of 10 minutes. After sintering, the sample is cooled and depressurized, and then surface polished and processed.

[0044] The PcBN samples prepared in Example 1 were subjected to performance tests. The test process used the FM-ARS900 semi-automatic micro-measurement system from Future-Tech, Japan. The microhardness of the sample was measured at a pressure of 30N for 15s, and the fracture toughness was calculated based on the crack size. The flexural strength of the sample was measured using a WDW-50 universal electronic material testing machine. The wear ratio of the sample was measured using a domestically produced MA6025 universal tool grinder with a green SiC grinding wheel. Specific test results: The flexural strength, microhardness, and fracture toughness values ​​of PcBN were 602MPa, 44.88GPa, and 6.53MPa·m, respectively. 1 / 2 , wear ratio 7352.

[0045] Example 2

[0046] The only difference between this embodiment and embodiment 1 is that in step S1, the raw materials include the following components by mass percentage: 80% main crystal phase, 19.5% binder, 0.5% reinforcing agent; in step S2, when mixing the materials, cemented carbide balls are used as grinding balls. The high temperature treatment is carried out at 3.0×10 -3 The sintering temperature is 550° C. and the sintering pressure is 5.5 GPa, the sintering temperature is 1500° C. and the holding time is 8 min.

[0047] The performance test of the PcBN sample prepared in Example 2 was carried out by the same test method as in Example 1. The specific test results showed that the flexural strength, microhardness and fracture toughness of PcBN were 625 MPa, 43.71 GPa and 6.67 MPa·m respectively. 1 / 2 , the wear ratio is 7521.

[0048] Example 3

[0049] The only difference between this embodiment and embodiment 1 is that in step S1, the raw materials include the following components by mass percentage: 80% main crystal phase, 18% binder, and 2% reinforcing agent; in step S2, when mixing the materials, cemented carbide balls are used as grinding balls. The high temperature treatment is carried out at 3.0×10 -3 The sintering temperature is 1500° C. and the holding time is 5 min.

[0050] The performance test of the PcBN sample prepared in Example 3 was carried out by the same test method as in Example 1. The specific test results are: the bending strength, microhardness and fracture toughness of PcBN are 621MPa, 42.81GPa and 7.12MPa·m respectively. 1 / 2, the wear ratio is 7636.

[0051] Example 4

[0052] The only difference between this embodiment and embodiment 1 is that in step S1, the raw materials comprise the following components, by mass percentage: 85% main crystalline phase, 13% binder, and 2% reinforcing agent. In step S2, the mixing time is 30 hours. The high-temperature and high-pressure sintering process parameters in step S3 are: sintering pressure of 6.0 GPa, sintering temperature of 1480°C, and holding time of 10 minutes.

[0053] The performance test of the PcBN sample prepared in Example 4 was carried out by the same test method as in Example 1. The specific test results are: the bending strength, microhardness and fracture toughness of PcBN are 632MPa, 44.28GPa and 6.91MPa·m respectively. 1 / 2 , the wear ratio is 7621.

[0054] Example 5

[0055] The only difference between this embodiment and embodiment 1 is that in step S1, the raw materials comprise the following components, by mass percentage: 83% main crystalline phase, 15% binder, and 2% reinforcing agent. In step S2, the mixing time is 28 hours. The high-temperature and high-pressure sintering process parameters in step S3 are: sintering pressure of 6.0 GPa, sintering temperature of 1550°C, and holding time of 7 minutes.

[0056] The performance test of the PcBN sample prepared in Example 5 was carried out by the same test method as in Example 1. The specific test results are: the bending strength, microhardness and fracture toughness of PcBN are 653 MPa, 43.86 GPa and 7.25 MPa·m respectively. 1 / 2 , the wear ratio is 7687.

[0057] While the embodiments of the present invention have been described above, the above description is intended to be exemplary, not exhaustive, and not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A method for preparing high-strength, high-toughness, and wear-resistant PcBN cutting tools by B4C-reinforced TiNbZrTa, characterized in that: The following steps are involved: S1. Select raw materials, which include the following components by mass percentage: 80%-85% main crystal phase, 13%-19.5% binder, and 0.5%-2.0% reinforcing agent; wherein the main crystal phase is cBN powder, the binder is TiNbZrTa powder, and the reinforcing agent is B4C powder; In this step, the cBN powder is first placed in a dilute hydrochloric acid solution with a mass fraction of 10% to 30%, boiled for 10 minutes to 50 minutes, and then washed with distilled water. It is then placed in a NaOH solution with a mass fraction of 10% to 30%, boiled for 10 minutes to 50 minutes, and then washed with distilled water. After centrifugation, it is first washed with distilled water, then washed with anhydrous ethanol, and finally vacuum dried for use. S2. Mixing: adding the main crystal phase, binder and reinforcing agent to the solvent in proportion and mixing evenly to obtain a mixed slurry. The obtained mixed slurry is placed in a vacuum drying oven for drying and high-temperature treatment to obtain a mixed powder; In this step, a ball mill is used for mixing, and the weight ratio of the solvent, raw materials, and grinding balls in the ball mill is 2:1:

3. The mixing time is 24h~30h, and the grinding balls are zirconia balls or cemented carbide balls. S3, sintering, filling the mixed powder into a synthesis mold to form a synthesis block, and performing high temperature and high pressure sintering in a six-sided top press according to the set process parameters. After unloading and cooling to room temperature, the PcBN sample is taken out; S4. Brazing the PcBN sample sintered at high temperature and high pressure with the WC alloy substrate to obtain a PcBN tool.

2. The method for preparing a high-strength, high-toughness, and wear-resistant PcBN tool from B4C-reinforced TiNbZrTa according to claim 1, characterized in that: The cBN powder has a grain size of 4 μm-6 μm and a purity of 99.9%.

3. The method for preparing a high-strength, high-toughness, and wear-resistant PcBN tool by using B4C-reinforced TiNbZrTa according to claim 2, characterized in that: The TiNbZrTa powder has a grain size of 10 μm and a purity of 99.9%.

4. The method for preparing a high-strength, high-toughness, and wear-resistant PcBN tool from B4C-reinforced TiNbZrTa according to claim 3, characterized in that: The B4C powder has a grain size of 2 μm-4 μm and a purity of 99.9%.

5. The method for preparing a high-strength, high-toughness, and wear-resistant PcBN tool from B4C-reinforced TiNbZrTa according to claim 1, characterized in that: In step S2, the solvent is anhydrous ethanol.

6. The method for preparing a high-strength, high-toughness, and wear-resistant PcBN tool from B4C-reinforced TiNbZrTa according to claim 1, characterized in that: In step S2, the drying is carried out at 3.0×10 -3 The samples were dried under vacuum at 60°C for 24 h.

7. The method for preparing a high-strength, high-toughness, and wear-resistant PcBN cutting tool from B4C-reinforced TiNbZrTa according to claim 1, characterized in that: In step S2, the high temperature treatment is carried out at 3.0×10 -3 Pa in a vacuum environment and at a temperature of 500°C-600°C for 1h-3h.

8. A method for preparing a high-strength, high-toughness, and wear-resistant PcBN cutting tool according to any one of claims 1 to 7, characterized in that: In step S3, the process parameters of the high temperature and high pressure sintering are: sintering pressure of 5 GPa-6 GPa, sintering temperature of 1450° C.-1550° C., and holding time of 5 min-10 min.