Improved tungsten alloy sintering process

Abstract

The invention provides an improved tungsten alloy sintering process which comprises the following steps: (1) weighing the following components in parts by mass: 92-95 parts of W, 4-8 parts of Ni, 3-6 parts of Fe, 1.2-1.6 parts of Cr, 0.3-0.8 part of Co and 1.4-1.9 parts of modified lanthanum trioxide; (2) mixing the components in the step (1), and carrying out ultrasonic dispersion treatment in a treatment modification liquid; (3) washing with water, drying, and performing cold isostatic pressing to obtain a blank; (4) feeding the blank into a sintering furnace for sintering, and cooling for later use after sintering is finished; (5) the temperature is increased to 550-650 DEG C, rotary forging machining is conducted, then the temperature is reduced to 300-350 DEG C, and heat preservation is conducted for 10-20 min; and water-cooling to room temperature, and drying to obtain the tungsten alloy. The tungsten alloy is excellent in comprehensive performance and has wide market prospects.

Description

Technical Field

[0001] The present invention belongs to the technical field of alloys, and particularly relates to an improved sintering process for tungsten alloys. Background Art

[0002] Tungsten alloy is an alloy material composed of metallic tungsten and other metallic or non-metallic elements. Tungsten has become an important raw material for manufacturing alloys due to its high melting point (about 3422 °C), high density, high strength, and good heat resistance. Common tungsten alloys include tungsten steel, tungsten copper alloy, tungsten nickel iron alloy, and tungsten silver alloy, etc. Tungsten alloys have a very high melting point and are suitable for applications in high-temperature environments. They have excellent mechanical strength and can maintain good strength especially at high temperatures. The high density of tungsten alloys makes them very effective in applications such as counterweights and balance blocks. Tungsten alloys are hard and have good wear resistance, making them suitable for manufacturing various wear-resistant components. Some tungsten alloys (such as tungsten copper alloy) have good electrical and thermal conductivity and are suitable for the fields of electrical and thermal management.

[0003] Tungsten alloys can be used to manufacture high-temperature components of aircraft and rockets, such as engine nozzles, thermal protection systems, etc.; to manufacture various cutting tools, dies, and drills; to manufacture electronic components, medical devices, and sports goods: for golf club heads, fishing weights, etc., taking advantage of their high density characteristics. In short, due to their unique physical and chemical properties, tungsten alloys play an important role in many industrial and high-tech fields.

[0004] Although the sintering process of tungsten alloys can produce high-performance materials, there are also some inherent defects. For example: (1) Shape limitation: Processes such as hot pressing sintering can usually only produce products with relatively simple shapes, and complex geometric shapes are difficult to achieve through such processes, which limits the design flexibility of tungsten alloys. (2) Anisotropy: During the sintering process, due to the non-uniformity of the internal microstructure of the material, such as the orientation and distribution of grains, the properties of the finished material will vary in different directions, that is, anisotropy. This may affect the performance of the material in specific applications. (3) Difficulty in controlling the microstructure: During the sintering process, it is very difficult to precisely control the growth of grains, the presence of pores, and the distribution of the second phase, which may affect the density, strength, and toughness of the final product. (4) Difficulty in subsequent processing: Tungsten alloys themselves have extremely high hardness, which makes it very difficult to machine the products after hot pressing sintering, increasing the cost and complexity of subsequent finishing. (5) Harsh sintering conditions: The sintering of high-density tungsten alloys usually requires very high temperatures and pressures, which not only consume a large amount of energy but may also cause deformation of the material or other defects during the sintering process, such as the formation of pores. (6) Internal defects: Defects such as holes, cracks, and "bird nests" may appear during the sintering process, and these defects will reduce the strength and reliability of the material, especially in application scenarios under high stress. (7) Cost issues: The high-temperature and high-pressure sintering process, as well as the rarity and high melting point of tungsten alloys themselves, result in a relatively high cost for the entire production process.

[0005] Rare earth oxides refer to compounds formed by rare earth elements and oxygen, and they have extremely important applications in modern science and technology and industry. Rare earth elements include scandium (Sc), yttrium (Y), and lanthanide elements (from lanthanum La to lutetium Lu, a total of 15 elements), and the oxides of these elements are collectively called rare earth oxides. The application scope of rare earth oxides is extensive, including but not limited to: Electronics and optoelectronics industries: Used in the manufacture of displays, lasers, optical fiber communications, and solar cells. Catalysts: Used in catalytic reactions in petroleum refining, automotive exhaust purification, and chemical processes. Magnetic materials: Used in the manufacture of high-performance magnets, such as permanent magnets in hard disk drives and wind turbines. Ceramics and glass: As additives to improve the properties of materials, such as improving heat resistance, transparency, and mechanical strength. Grinding and polishing materials: Such as cerium oxide (CeO2) is used for the polishing of precision optical glass. Biomedical field: As drug carriers, biomarkers, and imaging enhancers. The research on the preparation, properties, and applications of rare earth oxides is an active field, and new discoveries and innovations are constantly driving their applications in high-tech industries.

[0006] Therefore, improving the tungsten alloy sintering process to enhance the performance of tungsten alloys has extremely high market value. Summary of the Invention

[0007] The object of the present invention is to provide an improved sintering process for tungsten alloy.

[0008] To achieve the above object, the present invention provides the following technical solutions: An improved sintering process for tungsten alloy, comprising the following steps: (1) Weigh the following components by mass parts: 92 - 95 parts of W, 4 - 8 parts of Ni, 3 - 6 parts of Fe, 1.2 - 1.6 parts of Cr, 0.3 - 0.8 parts of Co, and 1.4 - 1.9 parts of modified lanthanum trioxide; (2) Mix the components in step (1), and then place them in a treatment modification liquid for ultrasonic dispersion treatment; (3) Wash with water, dry, and then perform cold isostatic pressing to form a blank; (4) Subsequently, send the blank into a sintering furnace for sintering, the sintering temperature is 1700 - 1800 °C, and during the process of heating from 600 °C to the sintering temperature, a gas with a flow rate of 140 - 150 m 3 / h is introduced for more than 74% of the time. After sintering, cool and reserve; (5) Then raise the temperature to 550 - 650 °C for rotary forging, and then lower the temperature to 300 - 350 °C and keep warm for 10 - 20 min; cool to room temperature with water, and then dry to obtain tungsten alloy.

[0009] Further, the gas is selected from one or more of hydrogen, nitrogen, argon, and helium.

[0010] Further, the preparation method of the modified lanthanum trioxide is as follows: (1) Mix lanthanum trioxide and ethanol with a mass ratio of 1:4 - 6, and perform ultrasonic dispersion to obtain a lanthanum trioxide dispersion liquid; (2) Mix hexagonal boron nitride and an aqueous hydrochloric acid solution with a mass fraction of 7 - 19% with a mass ratio of 1:4 - 6, then add sodium tripolyphosphate and titanate coupling agent CS - 101, stir evenly, wash with water and dry to obtain a modified material; (3) Mix the lanthanum trioxide dispersion liquid and the modified material with a mass ratio of 3 - 5:1 evenly, wash with water and dry, and react at 160 - 165 °C for 20 - 30 min to obtain modified lanthanum trioxide.

[0011] Further, the mass of sodium tripolyphosphate accounts for 5 - 6% of the mass of hexagonal boron nitride.

[0012] Further, the mass of titanate coupling agent CS - 101 accounts for 1 - 1.5% of the mass of hexagonal boron nitride.

[0013] Further, the power of ultrasonic dispersion treatment is 350 - 400 W, and the ultrasonic treatment time is 10 - 20 min.

[0014] Further, the sintering time is 1.3 - 1.8 h.

[0015] Further, the pressure for cold isostatic pressing is 100 - 120 MPa, and the treatment time is 2 - 5 min.

[0016] Further, it is water-cooled to room temperature, and water at 4 - 7 °C is used for water-cooling treatment.

[0017] Further, it is cooled to 300 - 350 °C at a rate of 1 - 3 °C / s.

[0018] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows: 1. Elements such as Ni, Fe, Cr, and Co added to the tungsten alloy can form solid solutions in the tungsten matrix. The difference in the sizes of these solute atoms and matrix atoms will cause lattice distortion, increasing the resistance to dislocation movement, thereby improving the strength of the tungsten alloy.

[0019] 2. The tungsten alloy of the present invention contains additives. At high temperatures during sintering, it is very important to introduce gas with an ultra-conventional flow rate, which will promptly carry away a large amount of impurities generated during the sintering process, fully ensuring the sintering quality.

[0020] 3. The special treatment of modified lanthanum sesquioxide can improve its compatibility and interfacial bonding force with the alloy matrix, thereby enhancing the elongation of the tungsten alloy. Specific Embodiments

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Apparently, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0022] Example 1 This example provides an improved sintering process for tungsten alloy, including the following steps: (1) Weigh the following components according to parts by mass: 94 parts of W, 6 parts of Ni, 5 parts of Fe, 1.5 parts of Cr, 0.6 parts of Co, and 1.7 parts of modified lanthanum sesquioxide; (2) Mix the components in step (1), and then place them in a treatment modifier solution for ultrasonic dispersion treatment; (3) Then wash with water, dry, and then perform cold isostatic pressing to obtain a blank; (4) Subsequently, send the blank into a sintering furnace for sintering. The sintering temperature is 1750 °C. During the process of heating from 600 °C to the sintering temperature, gas with a flow rate of 145 m 3 / h is introduced for more than 74% of the time. After sintering, it is cooled for standby; (5) Then raise the temperature to 600 °C, carry out rotary forging, and then lower it to 320 °C and keep it warm for 15 min; cool it to room temperature with water and then dry it to obtain a tungsten alloy.

[0023] The gas is nitrogen The preparation method of the modified lanthanum trioxide is as follows: (1) Mix lanthanum trioxide and ethanol with a mass ratio of 1:5, and carry out ultrasonic dispersion to obtain a lanthanum trioxide dispersion; (2) Mix hexagonal boron nitride and a 12% hydrochloric acid aqueous solution with a mass ratio of 1:5, then add sodium tripolyphosphate and titanate coupling agent CS-101, stir evenly, wash with water and dry to obtain a modified material; (3) Mix the lanthanum trioxide dispersion and the modified material with a mass ratio of 4:1 evenly, wash with water and dry, and react at 162 °C for 25 min to obtain modified lanthanum trioxide.

[0024] The mass of sodium tripolyphosphate accounts for 5.5% of the mass of hexagonal boron nitride.

[0025] The mass of titanate coupling agent CS-101 accounts for 1.2% of the mass of hexagonal boron nitride.

[0026] The power of the ultrasonic dispersion treatment is 370 W and the ultrasonic time is 15 min.

[0027] The sintering time is 1.5 h.

[0028] The pressure of cold isostatic pressing is 110 MPa and the treatment time is 4 min.

[0029] Cool it to room temperature with water, and use water at 6 °C for water cooling treatment.

[0030] Lower the temperature to 320 °C at a rate of 2 °C / s.

[0031] Example 2 This example provides an improved tungsten alloy sintering process, including the following steps: (1) Weigh the following components according to mass parts: 92 parts of W, 4 parts of Ni, 3 parts of Fe, 1.2 parts of Cr, 0.3 parts of Co and 1.4 parts of modified lanthanum trioxide; (2) Mix the components in step (1), and then place them in a treatment modifier solution for ultrasonic dispersion treatment; (3) Wash with water and dry again, and then carry out cold isostatic pressing to obtain a blank; (4) Then send the blank into a sintering furnace for sintering, the sintering temperature is 1700 °C, and during more than 74% of the time when the temperature rises from 600 °C to the sintering temperature, introduce a gas with a flow rate of 140 m 3 / hour, after sintering is completed, cool and reserve; (5) Then raise the temperature to 550 °C and perform rotary swaging, and then lower the temperature to 300 °C and keep it warm for 10 min; cool it to room temperature with water and then dry it to obtain a tungsten alloy.

[0032] The gas is argon.

[0033] The preparation method of the modified lanthanum trioxide is as follows: (1) Mix lanthanum trioxide and ethanol with a mass ratio of 1:4, and perform ultrasonic dispersion to obtain a lanthanum trioxide dispersion; (2) Mix hexagonal boron nitride and a 7% hydrochloric acid aqueous solution with a mass ratio of 1:4, then add sodium tripolyphosphate and titanate coupling agent CS-101, stir evenly, wash with water and dry to obtain a modified material; (3) Mix the lanthanum trioxide dispersion and the modified material with a mass ratio of 3:1 evenly, wash with water and dry, and react at 160 °C for 20 min to obtain modified lanthanum trioxide.

[0034] The mass of sodium tripolyphosphate accounts for 5% of the mass of hexagonal boron nitride.

[0035] The mass of titanate coupling agent CS-101 accounts for 1% of the mass of hexagonal boron nitride.

[0036] The power of the ultrasonic dispersion treatment is 350 W and the ultrasonic time is 10 min.

[0037] The sintering time is 1.3 h.

[0038] The pressure of cold isostatic pressing is 100 MPa and the treatment time is 2 min.

[0039] Cool it to room temperature with water, and use water at 4 °C for water cooling treatment.

[0040] Lower the temperature to 300 °C at a rate of 1 °C / s.

[0041] Example 3 This example provides an improved tungsten alloy sintering process, including the following steps: (1) Weigh the following components according to mass parts: 95 parts of W, 8 parts of Ni, 6 parts of Fe, 1.6 parts of Cr, 0.8 part of Co, and 1.9 parts of modified lanthanum trioxide; (2) Mix the components in step (1), and then place them in a treatment modification liquid for ultrasonic dispersion treatment; (3) Wash with water and dry again, and then perform cold isostatic pressing to obtain a blank; (4) Then send the blank into a sintering furnace for sintering, the sintering temperature is 1800 °C, and during more than 74% of the time when the temperature rises from 600 °C to the sintering temperature, introduce a flow rate of 150 m 3The gas is at [X] per hour, the sintering is completed, and it is cooled for standby; (5) Then raise the temperature to 650 °C for rotary forging, and then lower it to 350 °C and hold for 20 min; cool it to room temperature with water and then dry it to obtain the tungsten alloy.

[0042] The gas is argon.

[0043] The preparation method of the modified lanthanum sesquioxide is as follows: (1) Mix lanthanum sesquioxide and ethanol in a mass ratio of 1:6, and disperse them ultrasonically to obtain a lanthanum sesquioxide dispersion; (2) Mix hexagonal boron nitride and a 19% hydrochloric acid aqueous solution in a mass ratio of 1:6, then add sodium tripolyphosphate and titanate coupling agent CS-101, stir evenly, wash with water and dry to obtain a modified material; (3) Mix the lanthanum sesquioxide dispersion and the modified material in a mass ratio of 5:1 evenly, wash with water and dry, and react at 165 °C for 30 min to obtain the modified lanthanum sesquioxide.

[0044] The mass of sodium tripolyphosphate accounts for 6% of the mass of hexagonal boron nitride.

[0045] The mass of titanate coupling agent CS-101 accounts for 1.5% of the mass of hexagonal boron nitride.

[0046] The power of the ultrasonic dispersion treatment is 400 W, and the ultrasonic time is 20 min.

[0047] The sintering time is 1.8 h.

[0048] The pressure of cold isostatic pressing is 120 MPa, and the treatment time is 5 min.

[0049] Cool it to room temperature with water, and use water at 7 °C for water cooling treatment.

[0050] Lower the temperature to 350 °C at a rate of 3 °C / s.

[0051] Comparative Example 1 The difference between this comparative example and Example 1 is: different components.

[0052] An improved tungsten alloy sintering process includes the following steps: (1) Weigh the following components according to mass parts: 97 parts of W, 5 parts of Ni, 2 parts of Fe, 4.5 parts of Cr, 0.6 parts of Co, and 0.7 parts of modified lanthanum sesquioxide; (2) Mix the components in step (1), and then place them in a treatment modification liquid for ultrasonic dispersion treatment; (3) Wash with water, dry, and then perform cold isostatic pressing to obtain a blank; (4) Subsequently, the blank is fed into a sintering furnace for sintering at a sintering temperature of 1750 °C. During the process of heating the temperature from 600 °C to the sintering temperature, a gas with a flow rate of 145 m 3 / h is introduced for more than 74% of the time. After sintering is completed, it is cooled for standby; (5) Then the temperature is raised to 600 °C for rotary forging, and then lowered to 320 °C and held for 15 min; it is water-cooled to room temperature and then dried to obtain a tungsten alloy.

[0053] The gas is nitrogen The preparation method of the modified lanthanum trioxide is as follows: (1) Mix lanthanum trioxide and ethanol with a mass ratio of 1:5, and perform ultrasonic dispersion to obtain a lanthanum trioxide dispersion; (2) Mix hexagonal boron nitride and a 12% hydrochloric acid aqueous solution with a mass ratio of 1:5, then add sodium tripolyphosphate and titanate coupling agent CS-101, stir evenly, wash with water and dry to obtain a modified material; (3) Mix the lanthanum trioxide dispersion and the modified material with a mass ratio of 4:1 evenly, wash with water and dry, and react at 162 °C for 25 min to obtain modified lanthanum trioxide.

[0054] The mass of sodium tripolyphosphate accounts for 5.5% of the mass of hexagonal boron nitride.

[0055] The mass of titanate coupling agent CS-101 accounts for 1.2% of the mass of hexagonal boron nitride.

[0056] The power of the ultrasonic dispersion treatment is 370 W, and the ultrasonic time is 15 min.

[0057] The sintering time is 1.5 h.

[0058] The pressure of cold isostatic pressing is 110 MPa, and the treatment time is 4 min.

[0059] Water-cooled to room temperature, and water-cooling treatment is carried out with water at 6 °C.

[0060] Cool to 320 °C at a rate of 2 °C / s.

[0061] Comparative Example 2 The difference between this comparative example and Example 1 is: different sintering methods.

[0062] An improved tungsten alloy sintering process includes the following steps: (1) Weigh the following components according to mass parts: 94 parts of W, 6 parts of Ni, 5 parts of Fe, 1.5 parts of Cr, 0.6 parts of Co, and 1.7 parts of modified lanthanum trioxide; (2) Mix the components in step (1), and then place them in a treatment modification liquid for ultrasonic dispersion treatment; (3) Then, wash with water again, dry, and perform cold isostatic pressing to obtain a blank. (4) Subsequently, send the blank into a sintering furnace for sintering at a sintering temperature of 1750 °C. After sintering is completed, cool it for standby. (5) Then, raise the temperature to 600 °C for rotary forging, and then lower the temperature to 320 °C and hold for 15 min. Cool it to room temperature with water and then dry to obtain a tungsten alloy.

[0063] The gas is nitrogen. The preparation method of the modified lanthanum sesquioxide is as follows: (1) Mix lanthanum sesquioxide and ethanol at a mass ratio of 1:5, and perform ultrasonic dispersion to obtain a lanthanum sesquioxide dispersion. (2) Mix hexagonal boron nitride and a 12% hydrochloric acid aqueous solution at a mass ratio of 1:5, then add sodium tripolyphosphate and titanate coupling agent CS-101, stir evenly, wash with water and dry to obtain a modified material. (3) Mix the lanthanum sesquioxide dispersion and the modified material at a mass ratio of 4:1 evenly, wash with water and dry, and react at 162 °C for 25 min to obtain modified lanthanum sesquioxide.

[0064] The mass of sodium tripolyphosphate accounts for 5.5% of the mass of hexagonal boron nitride.

[0065] The mass of titanate coupling agent CS-101 accounts for 1.2% of the mass of hexagonal boron nitride.

[0066] The power of ultrasonic dispersion treatment is 370 W, and the ultrasonic time is 15 min.

[0067] The sintering time is 1.5 h.

[0068] The pressure of cold isostatic pressing is 110 MPa, and the treatment time is 4 min.

[0069] Cool it to room temperature with water, and use water at 6 °C for water cooling treatment.

[0070] Lower the temperature to 320 °C at a rate of 2 °C / s.

[0071] Comparative Example 3 The difference between this comparative example and Example 1 is that the lanthanum sesquioxide is not modified.

[0072] An improved tungsten alloy sintering process includes the following steps: (1) Weigh the following components according to mass parts: 94 parts of W, 6 parts of Ni, 5 parts of Fe, 1.5 parts of Cr, 0.6 parts of Co, and 1.7 parts of lanthanum sesquioxide. (2) Mix the components in step (1), and then place them in a treatment modification liquid for ultrasonic dispersion treatment. (3) Then wash with water again, dry, and perform cold isostatic pressing to obtain a blank; (4) Subsequently, feed the blank into a sintering furnace for sintering. The sintering temperature is 1750 °C. During the process of heating from 600 °C to the sintering temperature, a gas with a flow rate of 145 m 3 / h is introduced. After sintering is completed, cool it for standby; (5) Then raise the temperature to 600 °C, perform rotary forging, and then lower the temperature to 320 °C and hold for 15 min; cool it to room temperature with water and then dry to obtain a tungsten alloy.

[0073] The gas is nitrogen The sintering time is 1.5 h.

[0074] The pressure of cold isostatic pressing is 110 MPa, and the treatment time is 4 min.

[0075] Cool it to room temperature with water, and use water at 6 °C for water cooling treatment.

[0076] Lower the temperature to 320 °C at a rate of 2 °C / s.

[0077] Comparative Example 4 The difference between this comparative example and Example 1 is: different sintering methods.

[0078] An improved sintering process for tungsten alloy, comprising the following steps: (1) Weigh the following components according to parts by mass: 94 parts of W, 6 parts of Ni, 5 parts of Fe, 1.5 parts of Cr, 0.6 parts of Co, and 1.7 parts of modified lanthanum trioxide; (2) Mix the components in step (1), and then place them in a treatment modification liquid for ultrasonic dispersion treatment; (3) Then wash with water again, dry, and perform cold isostatic pressing to obtain a blank; (4) Subsequently, feed the blank into a sintering furnace for sintering. The sintering temperature is 1750 °C. During the process of heating from 1000 °C to the sintering temperature, a gas with a flow rate of 130 m 3 / h is introduced. After sintering is completed, cool it for standby; (5) Then raise the temperature to 600 °C, perform rotary forging, and then lower the temperature to 320 °C and hold for 15 min; cool it to room temperature with water and then dry to obtain a tungsten alloy.

[0079] The gas is nitrogen The preparation method of the modified lanthanum trioxide is: (1) Mix lanthanum trioxide and ethanol with a mass ratio of 1:5, and perform ultrasonic dispersion to obtain a lanthanum trioxide dispersion liquid; (2) Mix hexagonal boron nitride with a mass ratio of 1:5 and an aqueous hydrochloric acid solution with a mass fraction of 12%, then add sodium tripolyphosphate and titanate coupling agent CS-101, stir evenly, wash with water and dry to obtain a modified material; (3) Mix the lanthanum oxide dispersion with a mass ratio of 4:1 and the modified material evenly, wash with water and dry, and react at 162 °C for 25 min to obtain modified lanthanum oxide.

[0080] The mass of sodium tripolyphosphate accounts for 5.5% of the mass of hexagonal boron nitride.

[0081] The mass of titanate coupling agent CS-101 accounts for 1.2% of the mass of hexagonal boron nitride.

[0082] The power of ultrasonic dispersion treatment is 370 W and the ultrasonic time is 15 min.

[0083] The sintering time is 1.5 h.

[0084] The pressure of cold isostatic pressing is 110 MPa and the treatment time is 4 min.

[0085] Cool to room temperature with water cooling, and use water at 6 °C for water cooling treatment.

[0086] Cool to 320 °C at a rate of 2 °C / s.

[0087] Comparative Example 5 The difference between this comparative example and Example 1 is: different components.

[0088] An improved tungsten alloy sintering process includes the following steps: (1) Weigh the following components by mass parts: 94 parts of W, 6 parts of Ni, 4 parts of Fe, 0.5 part of Cr, 1.6 parts of Co and 2.7 parts of modified lanthanum oxide; (2) Mix the components in step (1), and then place them in a treatment modification solution for ultrasonic dispersion treatment; (3) Wash with water and dry again, and then perform cold isostatic pressing to obtain a blank; (4) Then send the blank into a sintering furnace for sintering, the sintering temperature is 1750 °C, and during more than 74% of the time when the temperature rises from 600 °C to the sintering temperature, introduce a gas with a flow rate of 145 m 3 / hour, after sintering is completed, cool and set aside; (5) Then raise the temperature to 600 °C, perform rotary forging, then lower the temperature to 320 °C, keep warm for 15 min; cool to room temperature with water, and dry again to obtain a tungsten alloy.

[0089] The gas is nitrogen The preparation method of the modified lanthanum oxide is: (1) Mix lanthanum oxide and ethanol at a mass ratio of 1:5, and disperse them by ultrasonic treatment to obtain a lanthanum oxide dispersion; (2) Mix hexagonal boron nitride and a hydrochloric acid aqueous solution with a mass fraction of 12% at a mass ratio of 1:5, then add sodium tripolyphosphate and titanate coupling agent CS-101, stir evenly, wash with water and dry to obtain a modified material; (3) Mix the lanthanum oxide dispersion and the modified material at a mass ratio of 4:1 evenly, wash with water and dry, and react at 162 °C for 25 min to obtain modified lanthanum oxide.

[0090] The mass of sodium tripolyphosphate accounts for 5.5% of the mass of hexagonal boron nitride.

[0091] The mass of titanate coupling agent CS-101 accounts for 1.2% of the mass of hexagonal boron nitride.

[0092] The power of ultrasonic dispersion treatment is 370 W, and the ultrasonic time is 15 min.

[0093] The sintering time is 1.5 h.

[0094] The pressure of cold isostatic pressing is 110 MPa, and the treatment time is 4 min.

[0095] Cool to room temperature with water, and use water at 6 °C for water cooling treatment.

[0096] Cool to 320 °C at a rate of 2 °C / s.

[0097] Performance test Use a HMASC1000SZA microhardness tester to measure the microhardness of the alloy, and use an AG-I 250KN precision universal material testing machine to measure the tensile strength of the alloy; Perform performance tests on the tungsten alloys of the examples and comparative examples; Table 1 Performance test results

[0098] From the above performance test results, it can be seen that the tungsten alloys of Examples 1-3 have good comprehensive performance, especially the comprehensive performance of Example 1 is the most prominent. This is mainly because of the synergistic effect between components and the influence of the sintering process.

[0099] In the comparative example, since the necessary technical solutions were not adopted, its performance in the corresponding performance tests was significantly worse than that of the example. Elements such as Ni, Fe, Cr, and Co added to the tungsten alloy can form solid solutions in the tungsten matrix. The difference in the sizes of these solute atoms and matrix atoms will cause lattice distortion, increasing the resistance to dislocation movement, thereby improving the strength of the tungsten alloy. The tungsten alloy contains additives. When sintering at high temperature, it is very important to introduce gas with an ultra-conventional flow rate, which will promptly carry away a large amount of impurities generated during the sintering process, fully ensuring the sintering quality. The special treatment of modified lanthanum trioxide can improve its compatibility and interfacial bonding force with the alloy matrix, thereby enhancing the elongation of the tungsten alloy. The above experimental results further prove the importance of the technical solutions defined in the present invention for its technical effects.

[0100] The above is the preferred implementation mode of the present invention. It should be noted that for those of ordinary skill in the art of this technology, without departing from the principle described in the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. An improved tungsten alloy sintering process, characterized in that: The following steps are involved: (1) Weigh the following components by mass: 92-95 parts of W, 4-8 parts of Ni, 3-6 parts of Fe, 1.2-1.6 parts of Cr, 0.3-0.8 parts of Co and 1.4-1.9 parts of modified lanthanum trioxide; (2) mixing the components in step (1), and then placing them in a treatment and modification liquid for ultrasonic dispersion treatment; (3) Washing, drying, and cold isostatic pressing to obtain a blank; (4) The blank is then fed into a sintering furnace for sintering at a temperature of 1700-1800°C. During the period of more than 74% of the time when the temperature rises from 600°C to the sintering temperature, the flow rate is 140-150m 3 / hour of gas, sintering is completed, cooling is performed for standby use; (5) The temperature is then raised to 550-650°C for rotary forging, then lowered to 300-350°C for 10-20 minutes; cooled to room temperature and dried to obtain tungsten alloy.

2. The improved tungsten alloy sintering process according to claim 1, characterized in that: The gas is selected from one or more of hydrogen, nitrogen, argon and helium.

3. The improved tungsten alloy sintering process according to claim 1, characterized in that: The preparation method of the modified lanthanum trioxide is: (1) mixing lanthanum trioxide and ethanol in a mass ratio of 1:4-6, and ultrasonically dispersing them to obtain a lanthanum trioxide dispersion; (2) Mix hexagonal boron nitride in a mass ratio of 1:4-6 and a hydrochloric acid aqueous solution in a mass fraction of 7-19%, then add sodium tripolyphosphate and titanate coupling agent CS-101, stir evenly, wash with water, and dry to obtain a modified material; (3) Evenly mix the lanthanum trioxide dispersion and the modified material in a mass ratio of 3-5:1, wash with water, dry, and react at 160-165° C. for 20-30 minutes to obtain modified lanthanum trioxide.

4. The improved tungsten alloy sintering process according to claim 3, characterized in that: The mass of sodium tripolyphosphate accounts for 5-6% of the mass of hexagonal boron nitride.

5. The improved tungsten alloy sintering process according to claim 3, characterized in that: The mass of titanate coupling agent CS-101 accounts for 1-1.5% of the mass of hexagonal boron nitride.

6. The improved tungsten alloy sintering process according to claim 3, characterized in that: The power of ultrasonic dispersion treatment is 350-400W, and the ultrasonic treatment time is 10-20min.

7. The improved tungsten alloy sintering process according to claim 1, characterized in that: The sintering time is 1.3-1.8h.

8. The improved tungsten alloy sintering process according to claim 1, characterized in that: The pressure of cold isostatic pressing is 100-120MPa, and the pressure holding time is 2-5min.

9. The improved tungsten alloy sintering process according to claim 1, characterized in that: Cool to room temperature with water at 4-7°C.

10. The improved tungsten alloy sintering process according to claim 1, characterized in that: Decrease to 300-350℃ at a rate of 1-3℃ / s.

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