A high volume ratio carbide particle reinforced tungsten metal composite material and preparation method thereof

Abstract

The present invention provides a high volume ratio carbide particle reinforced tungsten metal composite material and a preparation method thereof, wherein the metal composite material is composed of tungsten and carbide ceramic particles, wherein the carbide ceramic particles account for 5-70% and the tungsten accounts for 30-95% by volume. The high volume ratio carbide particle reinforced tungsten metal composite material of the present invention has fine and uniform grain structure, a density of more than 98%, a hardness of not less than 500HV30, and high temperature strength, and the high temperature strength at 2000°C can reach up to 200MPa.

Description

Technical Field

[0001] The invention relates to the technical field of powder metallurgy, and in particular to a high volume ratio carbide particle reinforced tungsten metal composite material and a preparation method thereof. Background Art

[0002] Metal tungsten has the advantages of high melting point, high high temperature mechanical properties, low thermal expansion coefficient, etc., and is widely used in aerospace, defense industry and nuclear industry. However, tungsten has high density and poor high temperature oxidation resistance, which limits its application in high temperature service conditions.

[0003] In order to improve the mechanical properties of tungsten to adapt to the high temperature extreme environment in cutting-edge science and technology fields such as aerospace, in the prior art, a trace amount of second phase particles are usually added to tungsten metal and the high temperature and ablation resistance of tungsten is improved by deformation strengthening, such as adding rare earth oxide particles such as La2O3 (<1%) or carbide particles such as TiC, ZrC, HfC (<1%). There is basically no prior art that adds a high proportion of second phase particles, because it is difficult to prepare, the material is brittle, it is easy to crack during deformation processing, the yield is low, and the improvement of high temperature strength and hardness is limited. In addition, due to the low content of the second phase particles added in the prior art, the density of the composite material is high and the high temperature strength is low, which cannot meet the application of special extreme service environments. Therefore, it is particularly important to develop a tungsten composite material containing a high proportion of reinforcing phase and its preparation method.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] The object of the present invention is to provide a high volume ratio carbide particle reinforced tungsten metal composite material and a preparation method thereof. The composite material has fine and uniform grain structure, a density of more than 98%, a hardness of not less than 500HV30, high temperature strength, and a high temperature strength of up to 200MPa at 2000°C.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] The invention provides a high volume ratio carbide particle reinforced tungsten metal composite material, which consists of tungsten and carbide ceramic particles. According to volume percentage, the carbide ceramic particles account for 5-70% and the tungsten accounts for 30-95%.

[0008] Furthermore, the carbide ceramic particles include at least one of titanium carbide ceramic particles, zirconium carbide ceramic particles, and hafnium carbide ceramic particles.

[0009] In addition, the present invention also provides a method for preparing the above-mentioned high volume ratio carbide particle reinforced tungsten metal composite material, comprising the following steps:

[0010] (1) Powder mixing: weighing tungsten powder and carbide powder according to the volume percentages of claim 1 or 2 respectively, mixing them, and subjecting the mixed powder to wet ball milling to obtain tungsten alloy powder;

[0011] (2) Pressing: Put the tungsten alloy powder into the mold and cold isostatically press to obtain a compact;

[0012] (3) Pre-sintering and reducing: Pre-sintering and reducing the compact obtained in step (2) in a hydrogen atmosphere sintering furnace to obtain a pre-sintered compact;

[0013] (4) Shaping: Shaping the pre-sintered blank obtained in step (3) into a desired shape and size;

[0014] (5) Hot isostatic pressing: The pre-sintered blank after shaping is placed in a sleeve, and the sleeve opening is welded and then hot isostatic pressing is performed.

[0015] Furthermore, the tungsten powder has a Fisher particle size of 1.0 to 3.0 μm;

[0016] And / or, the purity of the tungsten powder is ≥ 99.97%;

[0017] And / or, the carbide powder has a particle size of 20 to 50 nm.

[0018] Furthermore, the ball-to-material ratio in the wet ball milling process in step (1) is 10 to 25:1;

[0019] and / or, the rotation speed of the ball mill is 400 rpm to 800 rpm;

[0020] and / or, the ball milling time is 20-45h;

[0021] And / or, the control agent used in the wet ball milling process is ethanol or acetone;

[0022] And / or, the wet ball milling process includes placing the mixed powder in a ball milling jar and performing high-energy ball milling under an inert atmosphere; preferably, the ball milling jar is a cemented carbide ball milling jar, and the grinding balls are cemented carbide balls.

[0023] Furthermore, the pressure of the cold isostatic pressing in step (2) is 150-250 MPa;

[0024] And / or, the cold isostatic pressing time is 10-20 minutes.

[0025] Furthermore, the pre-calcination reduction temperature in step (3) is 1300-1500°C;

[0026] And / or, the sintering time is 4-8h.

[0027] Furthermore, the shaping process in step (4) requires the surface roughness to be no greater than Ra6.3.

[0028] Furthermore, the hot isostatic pressing temperature in step (5) is 1500-2000°C;

[0029] And / or, the hot isostatic pressing pressure is 150-200 MPa;

[0030] And / or, the hot isostatic pressing treatment time is 4-8h.

[0031] Furthermore, in step (5), the sheath material used for hot isostatic pressing is titanium or tantalum;

[0032] and / or, the gap between the pre-sintered blank and the jacket is less than 0.2 mm;

[0033] and / or, using an electron beam welder in a vacuum of 4×10 -2 After Pa, the sleeve mouth is welded.

[0034] Compared with the prior art, the technical solution of the present invention has at least the following technical effects:

[0035] (1) The present invention prepares tungsten alloy by combining wet ball milling mixed raw materials, cold isostatic pressing, pre-sintering reduction, and hot isostatic pressing processes. Compared with conventional tungsten alloy pressureless sintering temperature, it reduces 300-800°C and can inhibit grain growth;

[0036] (2) The present invention improves the high temperature performance of tungsten alloy by adding a high volume fraction of carbide ceramic second phase particles into the tungsten matrix, strengthening the second phase particles, pinning dislocations and grain boundaries, and hindering the movement of grain boundaries. At the same time, the added ceramic phase has a low density, which can significantly reduce the weight of the tungsten alloy.

[0037] (3) The tungsten alloy prepared by the present invention has a simple process route. The combination of wet ball milling mixed raw materials, cold isostatic pressing, pre-sintering reduction, and hot isostatic pressing processes can reduce the low yield rate caused by the brittleness of the material. When a large proportion of tungsten carbide ceramics is added, the density is high, and it is not easy to crack during deformation processing, avoiding cracks caused by thermal deformation processing of refractory metals. The prepared material has fine and uniform grain structure and high high temperature strength. The high temperature strength at 2000°C can reach up to 200MPa. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. Among them:

[0039] Figure 1 This is a metallographic photograph of the high volume ratio carbide particle reinforced tungsten metal composite material prepared in Example 1. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme in the embodiment of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present invention. The process parameters of the following embodiments that do not specify specific conditions are usually based on conventional conditions.

[0041] The endpoints and any values ​​of the ranges disclosed in the present invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be regarded as specifically disclosed in the present invention.

[0042] According to a first aspect of the present invention, there is provided a high volume ratio carbide particle reinforced tungsten metal composite material, which is composed of tungsten and carbide ceramic particles. In terms of volume percentage, the carbide ceramic particles account for 5-70% (including 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65% and 70% and the numerical range between any two points), and the tungsten account for 30-95% (including 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90% and 95% and the numerical range between any two points).

[0043] The composite material provided by the present invention is mainly used in the fields of aerospace, national defense industry and nuclear industry. The metal composite material is generally composed of a metal phase and a ceramic reinforcement phase. Oxides and carbides are both conventional reinforcement phases. The reason why the second ceramic phase of the present invention is carbides rather than oxides is that the oxides have a lower melting point than carbides, and the oxide particles are easy to grow at high temperatures, which results in the oxide strengthening effect being lower than the carbide strengthening effect. In addition, the carbide content needs to be controlled within the scope of the present invention. If the carbide content is too low, the strengthening effect is not obvious. If the carbide content is too high, the brittleness of the obtained material will increase significantly, and the preparation difficulty will be higher.

[0044] As a preferred embodiment of the present invention, the carbide ceramic particles include at least one of titanium carbide (TiC) ceramic particles, zirconium carbide (ZrC) ceramic particles, and hafnium carbide (HfC) ceramic particles.

[0045] As a preferred embodiment of the present invention, the density of the high volume ratio carbide particle reinforced tungsten metal composite material is above 98% (for example, 98.2%, 98.5%, 99%, 99.5% and the numerical range between any two points), the hardness is not less than 500HV30 (for example, 510HV30, 550HV30, 570HV30, 600HV30 and the numerical range between any two points), and the high temperature strength at 2000°C can reach up to 200MPa (for example, 110Mpa, 130Mpa, 140Mpa, 150Mpa, 160Mpa, 170Mpa, 180Mpa, 200Mpa and the numerical range between any two points).

[0046] According to a second aspect of the present invention, there is also provided a method for preparing the above-mentioned high volume ratio carbide particle reinforced tungsten metal composite material, comprising the following steps:

[0047] (1) Powder mixing: Weigh tungsten powder and carbide powder according to the above volume percentages and mix them, and wet ball mill the mixed powder to obtain tungsten alloy powder;

[0048] (2) Pressing: Put the tungsten alloy powder into the mold and cold isostatically press to obtain a compact;

[0049] (3) Pre-sintering and reducing: Pre-sintering and reducing the compact obtained in step (2) in a hydrogen atmosphere sintering furnace to obtain a pre-sintered compact;

[0050] (4) Shaping: Shaping the pre-sintered blank obtained in step (3) into a desired shape and size;

[0051] (5) Hot isostatic pressing: The pre-sintered blank after shaping is placed in a sleeve, and the sleeve opening is welded and then hot isostatic pressing is performed.

[0052] By adding more second-phase particles to tungsten, the method of the present invention can be used to prepare a high-density blank, and the strength and hardness are also significantly improved. However, when ordinary pressure sintering and deformation processing are used to prepare tungsten metal composite materials, the sintering density is low and the deformation processing will cause cracking, and its strength and hardness are not improved. The process route of the present invention prepares a high-density blank through pressure sintering to improve performance, solving the problem that the previous ordinary pressure sintering process cannot prepare large-sized high-performance blanks. However, due to the high proportion of second-phase particles added, the brittleness of the material will exist. Therefore, in addition to limiting the added carbide to a certain proportion range, the present invention also uses a pre-sintering reduction process to effectively reduce the impurity element content of the blank, thereby improving the brittleness of the material.

[0053] In the above technical scheme, wet ball milling is adopted in step (1). Compared with dry ball milling, the powder uniformity of wet ball milling is better. Hot isostatic pressing is adopted in step (5). Compared with SPS spark plasma sintering, hot isostatic pressing can prepare large-sized products with uniform pressure. Compared with 2300°C of conventional pressureless sintered tungsten products, the sintering temperature of the present invention is greatly reduced, thereby reducing the abnormal growth of grains.

[0054] As a preferred embodiment of the present invention, the Fisher particle size of the tungsten powder is 1.0 to 3.0 μm (including 1.0 μm, 1.5 μm, 2.0 μm, 2.5 μm and 3.0 μm and the numerical range between any two points); by selecting tungsten powder of this particle size, the density of the final composite material will be higher.

[0055] Preferably, the purity of the tungsten powder is ≥ 99.97%;

[0056] Preferably, the particle size of the carbide powder is 20 to 50 nm (including 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm and 50 nm and the numerical range between any two points); the particle size of the carbide powder is preferably controlled within the scope of the present invention. If the particle size is too small, the particles are likely to agglomerate during the preparation process. If the particle size is too large, the strengthening effect as a ceramic phase is poor.

[0057] As a preferred embodiment of the present invention, the ball-to-material ratio in the wet ball milling process in step (1) is 10-25:1 (including 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1, 19:1, 20:1, 21:1, 22:1, 23:1, 24:1 and 25:1 and the numerical range between any two points); the ball-to-material ratio in the present invention is preferably controlled within the scope of the present invention. If the ball-to-material ratio is too low, the powder is not significantly refined; if the ball-to-material ratio is too high, the powder is refined but agglomeration occurs.

[0058] Preferably, the rotation speed of the ball mill is 400 rpm to 800 rpm (including 400 rpm, 500 rpm, 600 rpm, 700 rpm and 800 rpm and the numerical range between any two points);

[0059] Preferably, the ball milling time is 20-45 h (including 20 h, 25 h, 30 h, 35 h, 40 h and 45 h and the numerical range between any two points);

[0060] Preferably, the control agent used in the wet ball milling process is ethanol or acetone;

[0061] Preferably, the wet ball milling process comprises placing the mixed powder in a ball milling jar and performing high-energy ball milling under an inert atmosphere; preferably, the ball milling jar is a cemented carbide ball milling jar, and the grinding balls are cemented carbide balls.

[0062] As a preferred embodiment of the present invention, the pressure of cold isostatic pressing in step (2) is 150-250 MPa (including 150 MPa, 160 MPa, 170 MPa, 180 MPa, 190 MPa, 200 MPa, 210 MPa, 220 MPa, 230 MPa, 240 MPa and 250 MPa and the numerical range between any two points);

[0063] Preferably, the cold isostatic pressing time is 10-20 min (including 10 min, 11 min, 12 min, 13 min, 14 min, 15 min, 16 min, 17 min, 18 min, 19 min and 20 min and the numerical range between any two points).

[0064] As a preferred embodiment of the present invention, the pre-burning reduction temperature in step (3) is 1300-1500°C (including 1300°C, 1320°C, 1340°C, 1360°C, 1380°C, 1400°C, 1420°C, 1440°C, 1460°C, 1480°C and 1500°C and the numerical range between any two points); the pre-burning reduction temperature of the present invention is preferably controlled within this range. If the pre-burning reduction temperature is too high, the subsequent hot isostatic pressing density is low; if the pre-burning temperature is too low, the impurity removal effect is poor.

[0065] Preferably, the sintering time is 4-8h (including 4h, 5h, 6h, 7h and 8h and the numerical range between any two points). If the sintering time is too short, the impurity removal effect is insufficient; if the sintering time is too long, more energy is consumed and the production cost is high.

[0066] As a preferred embodiment of the present invention, the shaping process in step (4) requires the surface roughness to be no greater than Ra6.3.

[0067] As a preferred embodiment of the present invention, the hot isostatic pressing temperature in step (5) is 1500-2000°C (including 1500°C, 1550°C, 1600°C, 1650°C, 1700°C, 1750°C, 1800°C, 1850°C, 1900°C, 1950°C and 2000°C and the numerical range between any two points); the hot isostatic pressing treatment of the present invention reduces the sintering temperature of conventional tungsten alloy by 300-800°C.

[0068] Preferably, the hot isostatic pressing pressure is 150-200 MPa (including 150 MPa, 160 MPa, 170 MPa, 180 MPa, 190 MPa and 200 MPa and the numerical range between any two points);

[0069] Preferably, the hot isostatic pressing treatment time is 4-8 h (including 4 h, 5 h, 6 h, 7 h and 8 h and the numerical range between any two points).

[0070] In the above technical solution, the temperature, pressure and time of the hot isostatic pressing treatment are preferably controlled within the range of the present invention. If they exceed the set range, various properties of the composite material finally obtained will be reduced.

[0071] As a preferred embodiment of the present invention, the sheath material used for hot isostatic pressing in step (5) is titanium or tantalum. Since the metal phase of the present invention is tungsten-based and the hot isostatic pressing temperature is relatively high, special sheath materials such as titanium or tantalum are used.

[0072] Preferably, the gap between the pre-sintered blank and the jacket is less than 0.2 mm;

[0073] Preferably, an electron beam welder is used in a vacuum of 4×10 -2 After Pa, the sleeve mouth is welded.

[0074] The present invention will be further described in detail below with reference to specific embodiments and comparative examples.

[0075] Example 1

[0076] This embodiment provides a method for preparing a high volume ratio carbide particle reinforced tungsten metal composite material, comprising the following steps:

[0077] (1) Powder preparation: Wet mix titanium carbide powder with an average particle size of 30 nm and tungsten powder blank with a Fisher particle size of 1.5 μm and a purity of ≥99.97% at a volume percentage of W:TiC=80:20, place the powder in a ball mill and perform high-energy ball milling under an inert atmosphere. The ball milling jar used is a cemented carbide ball milling jar, the grinding balls are cemented carbide balls, and ethanol is used as a dispersant. The speed of high-energy ball milling is 400 rpm, the time is 35 hours, and the ball-to-material ratio is 12:1, and the mixed tungsten alloy powder is obtained;

[0078] (2) The tungsten alloy powder obtained in step 1 is loaded into a mold, and the cold isostatic pressing pressure is 200 MPa, and the holding time is 10 min;

[0079] (3) placing the tungsten alloy compact obtained in step 2 into a hydrogen atmosphere sintering furnace for pre-sintering reduction at a pre-sintering temperature of 1400° C. and a sintering time of 6 h;

[0080] (4) The tungsten alloy pre-sintered blank obtained in step 3 is subjected to shaping processing, and the surface roughness is required to be no greater than Ra6.3;

[0081] (5) Tantalum is selected as the sheath material, and the tungsten alloy pre-sintered blank obtained in step 4 is placed in a hot isostatic pressing sheath, and the gap between the blank and the tantalum sheath is required to be less than 0.2 mm;

[0082] (6) electron beam welding the blanks prepared in step 5;

[0083] (7) placing the package obtained in step 6 into a hot isostatic pressing furnace for hot isostatic pressing treatment, the hot isostatic pressing temperature is 1600° C., the hot isostatic pressing pressure is 160 MPa, and the hot isostatic pressing time is 5 h;

[0084] The high temperature tensile test in this embodiment is carried out in accordance with GB / T 4338-2006 "Metallic Material High Temperature Tensile Test Method". The tungsten alloy obtained in Example 1 has a density of 98.5%, a hardness of 620HV30, and a tensile strength of 120MPa at 2000°C. Figure 1 It can be seen that the metal composite material prepared in this embodiment has fine and uniform grains, and the average grain size is 3 μm.

[0085] Example 2

[0086] This embodiment provides a method for preparing a high volume ratio carbide particle reinforced tungsten metal composite material, comprising the following steps:

[0087] (1) Powder preparation: Wet mix titanium carbide powder with an average particle size of 30 nm and tungsten powder blank with a Fisher particle size of 1.5 μm and a purity of ≥99.97% at a volume percentage of W:TiC=70:30, place the powder in a ball mill and perform high-energy ball milling under an inert atmosphere. The ball milling jar used is a cemented carbide ball milling jar, the grinding balls are cemented carbide balls, and ethanol is used as a dispersant. The speed of high-energy ball milling is 400 rpm, the time is 35 hours, and the ball-to-material ratio is 12:1, and the mixed tungsten alloy powder is obtained;

[0088] (2) The tungsten alloy powder obtained in step 1 is loaded into a mold, and the cold isostatic pressing pressure is 200 MPa, and the holding time is 10 min;

[0089] (3) placing the tungsten alloy compact obtained in step 2 into a hydrogen atmosphere sintering furnace for pre-sintering reduction at a pre-sintering temperature of 1400° C. and a sintering time of 6 h;

[0090] (4) The tungsten alloy pre-sintered blank obtained in step 3 is subjected to shaping processing, and the surface roughness is required to be no greater than Ra6.3;

[0091] (5) Tantalum is selected as the sheath material, and the tungsten alloy pre-sintered blank obtained in step 4 is placed in a hot isostatic pressing sheath, and the gap between the blank and the tantalum sheath is required to be less than 0.2 mm;

[0092] (6) electron beam welding the blanks prepared in step 5;

[0093] (7) placing the package obtained in step 6 into a hot isostatic pressing furnace for hot isostatic pressing treatment, the hot isostatic pressing temperature is 1700° C., the hot isostatic pressing pressure is 170 MPa, and the hot isostatic pressing time is 5 h;

[0094] The high temperature tensile test in this embodiment is carried out in accordance with GB / T4338-2006 "Metallic Material High Temperature Tensile Test Method". The tungsten alloy obtained in Example 2 has a density of 99.0%, a hardness of 695HV30, and a tensile strength of 155MPa at 2000°C.

[0095] Example 3

[0096] This embodiment provides a method for preparing a high volume ratio carbide particle reinforced tungsten metal composite material, comprising the following steps:

[0097] (1) Powder preparation: Wet mix zirconium carbide powder with an average particle size of 30 nm and tungsten powder blank with a Fisher particle size of 1.5 μm and a purity of ≥99.97% at a volume percentage of W:ZrC=50:50, place the powder in a ball mill and perform high-energy ball milling under an inert atmosphere. The ball milling jar used is a cemented carbide ball milling jar, the grinding balls are cemented carbide balls, and ethanol is used as a dispersant. The speed of high-energy ball milling is 400 rpm, the time is 35 hours, and the ball-to-material ratio is 12:1, and the mixed tungsten alloy powder is obtained;

[0098] (2) The tungsten alloy powder obtained in step 1 is loaded into a mold, and the cold isostatic pressing pressure is 200 MPa, and the holding time is 10 min;

[0099] (3) placing the tungsten alloy compact obtained in step 2 into a hydrogen atmosphere sintering furnace for pre-sintering reduction at a pre-sintering temperature of 1400° C. and a sintering time of 6 h;

[0100] (4) The tungsten alloy pre-sintered blank obtained in step 3 is subjected to shaping processing, and the surface roughness is required to be no greater than Ra6.3;

[0101] (5) Tantalum is selected as the sheath material, and the tungsten alloy pre-sintered blank obtained in step 4 is placed in a hot isostatic pressing sheath, and the gap between the blank and the tantalum sheath is required to be less than 0.2 mm;

[0102] (6) electron beam welding the blanks prepared in step 5;

[0103] (7) placing the package obtained in step 6 into a hot isostatic pressing furnace for hot isostatic pressing treatment, the hot isostatic pressing temperature is 1800° C., the hot isostatic pressing pressure is 180 MPa, and the hot isostatic pressing time is 5 h;

[0104] In this embodiment, the high temperature tensile test is carried out in accordance with GB / T 4338-2006 "Metallic Material High Temperature Tensile Test Method". The tungsten alloy obtained in Example 3 has a density of 99.1%, a hardness of 816HV30, and a tensile strength of 180MPa at 2000°C.

[0105] Example 4

[0106] This embodiment provides a method for preparing a high volume ratio carbide particle reinforced tungsten metal composite material, comprising the following steps:

[0107] (1) Powder preparation: Wet mix titanium carbide powder with an average particle size of 30 nm and tungsten powder blank with a Fisher particle size of 1.5 μm and a purity of ≥99.97% at a volume percentage of W:TiC=40:60, place the powder in a ball mill and perform high-energy ball milling under an inert atmosphere. The ball milling jar used is a cemented carbide ball milling jar, the grinding balls are cemented carbide balls, and ethanol is used as a dispersant. The speed of high-energy ball milling is 400 rpm, the time is 35 hours, and the ball-to-material ratio is 12:1, and the mixed tungsten alloy powder is obtained;

[0108] (2) The tungsten alloy powder obtained in step 1 is loaded into a mold, and the cold isostatic pressing pressure is 200 MPa, and the holding time is 10 min;

[0109] (3) placing the tungsten alloy compact obtained in step 2 into a hydrogen atmosphere sintering furnace for pre-sintering reduction at a pre-sintering temperature of 1400° C. and a sintering time of 6 h;

[0110] (4) The tungsten alloy pre-sintered blank obtained in step 3 is subjected to shaping processing, and the surface roughness is required to be no greater than Ra6.3;

[0111] (5) Tantalum is selected as the sheath material, and the tungsten alloy pre-sintered blank obtained in step 4 is placed in a hot isostatic pressing sheath, and the gap between the blank and the tantalum sheath is required to be less than 0.2 mm;

[0112] (6) electron beam welding the blanks prepared in step 5;

[0113] (7) placing the package obtained in step 6 into a hot isostatic pressing furnace for hot isostatic pressing treatment, the hot isostatic pressing temperature is 1900° C., the hot isostatic pressing pressure is 200 MPa, and the hot isostatic pressing time is 5 h;

[0114] In this embodiment, the high temperature tensile test is carried out in accordance with GB / T 4338-2006 "Metallic Material High Temperature Tensile Test Method". The tungsten alloy prepared in Example 4 has a density of 99.3%, a hardness of 840HV30, and a tensile strength of 210MPa at 2000°C.

[0115] Example 5

[0116] The remaining parameters and steps are consistent with those in Example 4, except that:

[0117] (1) Powder preparation: hafnium carbide powder with an average particle size of 40 nm and tungsten powder blank with a Fisher particle size of 2 μm and a purity of ≥99.97% are wet mixed at a volume percentage of W:HfC=90:10.

[0118] In this embodiment, the high temperature tensile test is carried out in accordance with GB / T 4338-2006 "Metallic Material High Temperature Tensile Test Method". The tungsten alloy prepared in Example 1 is 99.3%, the hardness is 545HV30, and the tensile strength at 2000°C reaches 105MPa.

[0119] Example 6

[0120] The remaining parameters and steps are consistent with those in Example 4, except that:

[0121] (1) placing the package obtained in step 6 into a hot isostatic pressing furnace for hot isostatic pressing, the hot isostatic pressing temperature is 1800° C., the hot isostatic pressing pressure is 180 MPa, and the hot isostatic pressing time is 5 h;

[0122] In this embodiment, the high temperature tensile test is carried out in accordance with GB / T 4338-2006 "Metallic Material High Temperature Tensile Test Method". The tungsten alloy obtained in Example 6 has a density of 98.6%, a hardness of 815HV30, and a tensile strength of 172MPa at 2000°C.

[0123] Example 7

[0124] The remaining parameters and steps are consistent with those in Example 1, except that:

[0125] (3) placing the tungsten alloy compact obtained in step 2 into a hydrogen atmosphere sintering furnace for pre-sintering reduction at a pre-sintering temperature of 1500° C. and a sintering time of 4 h;

[0126] The high temperature tensile test in this embodiment is carried out in accordance with GB / T 4338-2006 "Metallic Material High Temperature Tensile Test Method". The tungsten alloy obtained in Example 7 has a density of 98%, a hardness of 606HV30, and a tensile strength of 112MPa at 2000°C.

[0127] Example 8

[0128] This embodiment provides a method for preparing a high volume ratio carbide particle reinforced tungsten metal composite material, comprising the following steps:

[0129] (1) Powder preparation: Wet mix titanium carbide powder with an average particle size of 60nm and tungsten powder blank with a Fisher particle size of 4μm and a purity of ≥99.97% at a volume percentage of W:TiC=40:60, place the powder in a ball mill and perform high-energy ball milling under an inert atmosphere. The ball milling jar used is a cemented carbide ball milling jar, the grinding balls are cemented carbide balls, and ethanol is used as a dispersant. The speed of high-energy ball milling is 400rpm, the time is 35h, and the ball-to-material ratio is 12:1, and the mixed tungsten alloy powder is obtained;

[0130] (2) The tungsten alloy powder obtained in step 1 is loaded into a mold, and the cold isostatic pressing pressure is 200 MPa, and the holding time is 10 min;

[0131] (3) placing the tungsten alloy compact obtained in step 2 into a hydrogen atmosphere sintering furnace for pre-sintering reduction at a pre-sintering temperature of 1400° C. and a sintering time of 6 h;

[0132] (4) The tungsten alloy pre-sintered blank obtained in step 3 is subjected to shaping processing, and the surface roughness is required to be no greater than Ra6.3;

[0133] (5) Tantalum is selected as the sheath material, and the tungsten alloy pre-sintered blank obtained in step 4 is placed in a hot isostatic pressing sheath, and the gap between the blank and the tantalum sheath is required to be less than 0.2 mm;

[0134] (6) electron beam welding the blanks prepared in step 5;

[0135] (7) placing the package obtained in step 6 into a hot isostatic pressing furnace for hot isostatic pressing treatment, the hot isostatic pressing temperature is 2000° C., the hot isostatic pressing pressure is 200 MPa, and the hot isostatic pressing time is 5 h;

[0136] In this embodiment, the high temperature tensile test is carried out in accordance with GB / T 4338-2006 "Metallic Material High Temperature Tensile Test Method", and the obtained tungsten alloy has a density of 98.6%, a hardness of 819HV30, and a tensile strength of 190MPa at 2000°C.

[0137] Comparative Example 1

[0138] This comparative example provides a method for preparing a high volume ratio carbide particle reinforced tungsten metal composite material, comprising the following steps:

[0139] (1) Powder preparation: Wet mix zirconium carbide powder with an average particle size of 30 nm and tungsten powder blank with a Fisher particle size of 1.5 μm and a purity of ≥99.97% at a volume percentage of W:ZrC=50:50, place the powder in a ball mill and perform high-energy ball milling under an inert atmosphere. The ball milling jar used is a cemented carbide ball milling jar, the grinding balls are cemented carbide balls, and ethanol is used as a dispersant. The speed of high-energy ball milling is 400 rpm, the time is 35 hours, and the ball-to-material ratio is 12:1, and the mixed tungsten alloy powder is obtained;

[0140] (2) The tungsten alloy powder obtained in step 1 is loaded into a mold, and the cold isostatic pressing pressure is 200 MPa, and the holding time is 10 min;

[0141] (3) placing the tungsten alloy compact obtained in step 2 into a hydrogen atmosphere sintering furnace for pre-sintering reduction at a pre-sintering temperature of 1400° C. and a sintering time of 6 h;

[0142] (4) The tungsten alloy pre-sintered blank obtained in step 3 is subjected to shaping processing, and the surface roughness is required to be no greater than Ra6.3;

[0143] (5) Tantalum is selected as the sheath material, and the tungsten alloy pre-sintered blank obtained in step 4 is placed in a hot isostatic pressing sheath, and the gap between the blank and the tantalum sheath is required to be less than 0.2 mm;

[0144] (6) electron beam welding the blanks prepared in step 5;

[0145] (7) placing the package obtained in step 6 into a hot isostatic pressing furnace for hot isostatic pressing treatment, the hot isostatic pressing temperature is 1400° C., the hot isostatic pressing pressure is 180 MPa, and the hot isostatic pressing time is 5 h;

[0146] The high temperature tensile test in this comparative example was carried out in accordance with GB / T 4338-2006 "Metallic Material High Temperature Tensile Test Method", and the obtained tungsten alloy had a density of 96.2%, a hardness of 613HV30, and a tensile strength of 135MPa at 2000°C.

[0147] Comparative Example 2

[0148] The remaining parameters and steps are consistent with those in Example 3, except that:

[0149] (1) Wet-mix zirconium carbide powder with an average particle size of 30 nm and tungsten powder blank with a Fisher particle size of 1.5 μm and a purity of ≥99.97% at a volume percentage of W:ZrC=20:80.

[0150] After the blank was hot isostatically pressed, during the process of removing the sheath, the blank broke due to the high ceramic content and could not be processed.

[0151] Comparative Example 3

[0152] The remaining parameters and steps are consistent with those in Example 3, except that:

[0153] (1) Wet-mix zirconium carbide powder with an average particle size of 30 nm and tungsten powder blank with a Fisher particle size of 1.5 μm and a purity of ≥99.97% at a volume percentage of W:ZrC=98:2.

[0154] The high temperature tensile test in this comparative example was carried out in accordance with GB / T 4338-2006 "Metallic Material High Temperature Tensile Test Method", and the obtained tungsten alloy had a density of 99.5%, a hardness of 440HV30, and a tensile strength of 60MPa at 2000°C.

[0155] Comparative Example 4

[0156] This comparative example provides a method for preparing a high volume ratio carbide particle reinforced tungsten metal composite material, comprising the following steps:

[0157] (1) Powder preparation: Wet mix zirconium carbide powder with an average particle size of 30 nm and tungsten powder blank with a Fisher particle size of 1.5 μm and a purity of ≥99.97% at a volume percentage of W:ZrC=50:50, place the powder in a ball mill and perform high-energy ball milling under an inert atmosphere. The ball milling jar used is a cemented carbide ball milling jar, the grinding balls are cemented carbide balls, and ethanol is used as a dispersant. The speed of high-energy ball milling is 400 rpm, the time is 35 hours, and the ball-to-material ratio is 12:1, and the mixed tungsten alloy powder is obtained;

[0158] (2) The tungsten alloy powder obtained in step 1 is loaded into a mold, and the cold isostatic pressing pressure is 200 MPa, and the holding time is 10 min;

[0159] (3) placing the tungsten alloy compact obtained in step 2 into a hydrogen atmosphere sintering furnace for pressureless sintering at a sintering temperature of 2300° C. for a sintering time of 6 h;

[0160] The high temperature tensile test in this comparative example was carried out in accordance with GB / T 4338-2006 "Methods for high temperature tensile test of metallic materials"). The density of the obtained tungsten alloy was 85%, the hardness was 412HV30, and the tensile strength at 2000°C was 50MPa.

[0161] Comparative Example 5

[0162] The remaining parameters and steps are consistent with those in Example 1, except that:

[0163] (3) The tungsten alloy compact obtained in step 2 is placed in a hydrogen atmosphere sintering furnace for pre-sintering reduction. The pre-sintering temperature is 1200° C. and the sintering time is 6 h.

[0164] Because the pre-sintering temperature of this comparative example is relatively low, the impurity removal effect is poor, the impurity element content is high, and the material is brittle and easy to crack during processing.

[0165] Comparative Example 6

[0166] The remaining parameters and steps are consistent with those in Example 1, except that:

[0167] (3) placing the tungsten alloy compact obtained in step 2 into a hydrogen atmosphere sintering furnace for pre-sintering reduction at a pre-sintering temperature of 1600° C. and a sintering time of 6 h;

[0168] The high temperature tensile test in this comparative example was carried out in accordance with GB / T 4338-2006 "Metallic Material High Temperature Tensile Test Method", and the obtained tungsten alloy had a density of 97.6%, a hardness of 593HV30, and a tensile strength of 105MPa at 2000°C.

[0169] The high volume ratio carbide particle reinforced tungsten metal composite materials obtained in Examples 1-8 and Comparative Examples 1-6 were subjected to high temperature tensile tests according to GB / T 4338-2006 "Methods for high temperature tensile tests of metal materials". The specific test results are shown in Table 1:

[0170] Table 1

[0171]

[0172]

[0173] It can be seen from the above data that the comprehensive performance of the high volume ratio carbide particle reinforced tungsten metal composite material obtained in Examples 1-8 is significantly higher than that of Comparative Examples 1-6. In Comparative Example 1, the temperature of the hot isostatic pressing treatment is lower than the preferred range of the present invention, and the hardness and 2000°C tensile strength of the obtained composite material are reduced; in Comparative Example 2, the ceramic phase particle content is too high, resulting in the fracture of the blank; in Comparative Example 3, the ceramic phase particle content is too low, and the hardness and 2000°C tensile strength of the obtained composite material are significantly reduced; in Comparative Example 4, pressureless sintering is used to replace the hot isostatic pressing molding of the present invention, and the hardness, 2000°C tensile strength and density of the obtained composite material are significantly reduced; in Comparative Example 5, due to the low pre-sintering temperature, the impurity removal effect is not good, and the impurity element content is high, resulting in the material being brittle and easy to crack during processing; in Comparative Example 6, due to the pre-sintering temperature being higher than the preferred range of the present invention, the hardness and 2000°C tensile strength of the obtained composite material are reduced.

[0174] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A high volume ratio carbide particle reinforced tungsten metal composite material, characterized in that: It is composed of tungsten and carbide ceramic particles, in which the carbide ceramic particles account for 55-70% and tungsten accounts for 30-45% by volume; The density of high volume ratio carbide particle reinforced tungsten metal composite material is more than 98%, and the hardness is not less than 500HV30; A method for preparing a high volume ratio carbide particle reinforced tungsten metal composite material comprises the following steps: (1) Powder mixing: Weigh tungsten powder and carbide powder according to the above volume percentages and mix them, and wet ball mill the mixed powder to obtain tungsten alloy powder; (2) Pressing: Put the tungsten alloy powder into the mold and cold isostatically press to obtain a compact; (3) Pre-sintering and reducing: Pre-sintering and reducing the compact obtained in step (2) in a hydrogen atmosphere sintering furnace to obtain a pre-sintered compact; (4) Shaping: Shaping the pre-sintered blank obtained in step (3) into a desired shape and size; (5) Hot isostatic pressing: The pre-sintered blank after shaping is placed in a sleeve, and the sleeve opening is welded and then hot isostatic pressing is performed; The ball-to-material ratio in the wet ball milling process in step (1) is 10-25:1; the particle size of the carbide powder is 20-50 nm; In the step (3), the pre-calcination reduction temperature is 1300-1500° C. and the sintering time is 4-8 hours; In the step (5), the hot isostatic pressing temperature is 1500-2000° C.; the hot isostatic pressing pressure is 150-200 MPa; and the hot isostatic pressing treatment time is 4-8 hours.

2. The high volume ratio carbide particle reinforced tungsten metal composite material according to claim 1, characterized in that: The carbide ceramic particles include at least one of titanium carbide ceramic particles, zirconium carbide ceramic particles, and hafnium carbide ceramic particles.

3. A method for preparing a high volume ratio carbide particle reinforced tungsten metal composite material as claimed in claim 1 or 2, characterized in that: The steps include: (1) Powder mixing: weighing tungsten powder and carbide powder according to the volume percentages of claim 1 or 2 respectively, mixing them, and subjecting the mixed powder to wet ball milling to obtain tungsten alloy powder; (2) Pressing: Put the tungsten alloy powder into the mold and cold isostatically press to obtain a compact; (3) Pre-sintering and reducing: Pre-sintering and reducing the compact obtained in step (2) in a hydrogen atmosphere sintering furnace to obtain a pre-sintered compact; (4) Shaping: Shaping the pre-sintered blank obtained in step (3) into a desired shape and size; (5) Hot isostatic pressing: The pre-sintered blank after shaping is placed in a sleeve, and the sleeve opening is welded and then hot isostatic pressing is performed.

4. The preparation method according to claim 3, characterized in that: The tungsten powder has a Fisher particle size of 1.0 to 3.0 μm; And / or, the purity of the tungsten powder is ≥99.97%.

5. The preparation method according to claim 3, characterized in that: The ball milling speed is 400 rpm to 800 rpm; and / or, the ball milling time is 20-45h; And / or, the control agent used in the wet ball milling process is ethanol or acetone; And / or, the wet ball milling process includes placing the mixed powder in a ball milling jar and performing high-energy ball milling under an inert atmosphere; the ball milling jar is a cemented carbide ball milling jar, and the grinding balls are cemented carbide balls.

6. The preparation method according to claim 3, characterized in that: The pressure of the cold isostatic pressing in step (2) is 150-250 MPa; And / or, the cold isostatic pressing time is 10-20 minutes.

7. The preparation method according to claim 3, characterized in that: The shaping process in step (4) requires the surface roughness to be no greater than Ra6.

3.

8. The preparation method according to claim 3, characterized in that: In the step (5), the sheath material used for hot isostatic pressing is titanium or tantalum; and / or, the gap between the pre-sintered blank and the jacket is less than 0.2 mm; and / or, using an electron beam welder in a vacuum of 4×10 -2 After Pa, the sleeve mouth is welded.

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