Wear-resistant metal alloy suitable for titanium alloy surfaces of different shapes and preparation method of bimetallic product of wear-resistant metal alloy

Abstract

The invention belongs to the technical field of powder metallurgy, and relates to a wear-resistant metal alloy suitable for titanium alloy surfaces of different shapes and a preparation method of a bimetallic product of the wear-resistant metal alloy. The preparation method comprises the following steps: step 1, preparing raw material powder according to specified components, and preparing a compact SMK alloy cylindrical bar billet based on the raw material powder; 2, the SMK alloy cylindrical bar blank is sintered, and an SMK alloy electrode bar is obtained; 3, based on the SMK alloy electrode bar, wear-resistant metal spherical powder is prepared through a plasma rotating electrode method and screened; and 4, based on the screened wear-resistant metal spherical powder, the dual-metal workpiece with the needed shape and thickness is manufactured through the processes of bag manufacturing, powder filling, vacuumizing and seal welding, hot isostatic pressing and acid pickling bag removing. The problems that a hard layer prepared through a traditional method is low in thickness, uneven in hardness distribution, small in connection strength and the like can be effectively solved, and the requirements for high abrasion resistance and long service life of titanium alloy in the abrasion-resistant environment can be met.

Description

Technical Field

[0001] The invention belongs to the technical field of powder metallurgy, relates to the preparation of bimetallic parts on titanium alloy surfaces, and specifically relates to a wear-resistant metal alloy suitable for titanium alloy surfaces of different shapes and a preparation method of the bimetallic parts thereof. Background Art

[0002] Titanium alloys have shown their unique advantages in many fields due to their high strength, low density, excellent corrosion resistance, good biocompatibility, and stable high-temperature performance. In the field of aerospace, titanium alloy parts can significantly reduce the weight of aircraft, improve fuel efficiency, and increase range. At the same time, their high strength and good durability can ensure the safety of aircraft structures under complex flight conditions. In marine engineering, the seawater environment is highly corrosive. Titanium alloys are widely used in the manufacture of pipes, valves, pump bodies and other components due to their excellent corrosion resistance. This can not only ensure the long-term stable operation of equipment, but also reduce maintenance frequency, reduce maintenance costs, and greatly extend the service life of equipment. In the medical field, titanium alloys have become an ideal material for orthopedic implants and dental implants due to their good biocompatibility. It can closely integrate with human bones, promote bone healing, help patients recover faster, and improve the quality of life. In addition, in high-temperature environments, titanium alloys can still maintain good mechanical properties and chemical stability, so they have been widely used in high-temperature working scenes with high requirements such as aircraft engines, gas turbines, and nuclear reactors.

[0003] However, with the increase in the demand for working conditions, titanium alloys also have some shortcomings, mainly manifested in low hardness and poor wear resistance. The above shortcomings will affect the use of titanium alloys in load-bearing and friction environments. In response to the problem of poor wear resistance of titanium alloys, the current solution is to prepare a wear-resistant metal layer on the surface of titanium alloys to form a bimetallic material; common methods include explosive composite, brazing, surfacing, laser cladding, spraying, etc., but the above methods still have some defects: ① In terms of forming, explosive composite, brazing and other technologies can only form regular shapes such as plates and blocks, and it is difficult to form a wear-resistant metal layer on the surface of titanium alloy parts with special-shaped structures; ② In terms of performance, laser cladding, spraying and other methods can prepare a hard layer on the surface of complex titanium alloy parts, but the above processes mainly have the disadvantages of uneven hardness and thin hard layer (≤0.5mm), which cannot guarantee the long-term use of titanium alloys. At the same time, due to the large differences in composition and thermal expansion coefficient between titanium alloys and traditional wear-resistant alloys, it is difficult to form diffusion connections, and the alloy selection is difficult. An intermediate layer of material must be added to achieve the purpose of connection, which is bound to increase the difficulty and cost of forming technology.

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

[0005] The object of the present invention is to overcome the above-mentioned disadvantages of the prior art and provide a wear-resistant metal alloy applicable to titanium alloy surfaces of different shapes and a preparation method for its bimetallic parts, so as to solve the problems existing in the prior art such as the thin hard layer on the surface of titanium alloy parts, the great difficulty in forming complex shapes, the uneven structure of the hard layer, and the great difficulty in diffusion bonding of traditional metal materials, and provide favorable support and guarantee for the long-term use of titanium alloys and special-shaped parts in wear-resistant environments.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] On the one hand, the present invention provides a wear-resistant metal alloy applicable to titanium alloy surfaces of different shapes, which includes the following components by mass percentage: 2% - 8% of C powder, 1% - 6% of Si powder, 4% - 10% of B powder, 13% - 20% of Cr powder, and the rest is Ni powder. Among them, the purity of all components is not less than 95%, the particle sizes of C powder, Si powder, and B powder are between 5μm and 53μm, and the particle sizes of Cr powder and Ni powder are between 53μm and 150μm.

[0008] Specifically, the titanium alloys of different shapes include but are not limited to plate-shaped, columnar, conical, spherical, disk-shaped and other complex shapes. Among them,

[0009] For plate-shaped parts, the length is 30mm - 1500mm, the width is 50mm - 1000mm, and the height is 3mm - 500mm;

[0010] For columnar parts, the length (i.e., the height of the column) ranges from 30mm to 1500mm, and the bottom diameter is 50mm - 1000mm;

[0011] For conical parts, the height of the cone is 30mm - 1500mm, and the bottom diameter is 50mm - 1000mm; for spherical parts, the diameter of the sphere is 50mm - 1000mm; for disk-shaped parts, the diameter of the disk body (if it is a non-circular disk, the maximum outer diameter size is taken) is 50mm - 1000mm, and the thickness is 3mm - 500mm.

[0012] For titanium alloy parts with other complex shapes, the length, width and height are determined according to their maximum external dimensions, and the dimension range shall be implemented with reference to the following standards: the length is 30mm - 1500mm, the width is 50mm - 1000mm, and the height is 3mm - 500mm. It should be noted that when referring to the shape dimensions of titanium alloys, the "length", "width", "height", "diameter", "thickness", etc. mentioned are the maximum geometric dimensions of titanium alloy parts in the corresponding dimensions, that is, the effective dimensions.

[0013] On the other hand, the present invention also provides a preparation method for bimetallic parts applicable to titanium alloy surfaces of different shapes, including the following steps:

[0014] Step 1: Prepare raw material powders according to the composition of the wear-resistant metal alloy as described above, and obtain a dense SMK alloy cylindrical bar blank based on the raw material powders.

[0015] Step 2: Sinter the SMK alloy cylindrical bar blank to obtain an SMK alloy electrode bar.

[0016] Step 3: Based on the SMK alloy electrode bar, prepare wear-resistant metal spherical powders by the plasma rotating electrode process, and perform screening.

[0017] Step 4: Based on the screened wear-resistant metal spherical powders, obtain the target bimetallic part through the process of "making a cladding → filling powder → vacuumizing and sealing welding → hot isostatic pressing → pickling to remove the cladding".

[0018] Specifically, Step 1 includes:

[0019] Step 1.1: Ball mill and mix C powder, Si powder, B powder, Cr powder, and Ni powder according to specific mass percentages through a ball milling process; among them, all powders are mechanically ball milled in anhydrous ethanol with a purity ≥ 99%. The particle sizes of the C powder, Si powder, and B powder are all between 5 μm and 53 μm, and the particle sizes of the Cr powder and Ni powder are all between 53 μm and 150 μm. The ball milling process parameters are as follows: The grinding balls are nickel-based metal balls with a diameter of 3 mm to 15 mm, the ball milling vacuum degree ≤ 1.1×10 -3 Pa, the rotation speed is 150 r / min to 250 r / min, the single mixing amount ≤ 10 kg, and the single mixing time is 15 h to 20 h.

[0020] It should be noted that the diameter of the grinding balls can be adaptively selected according to the actual ball milling requirements. For example, 3 mm, 5 mm, 7 mm, 9 mm, 11 mm, 13 mm, or 15 mm, etc. can be selected, and they are not listed one by one here. Similarly, the ball milling rotation speed can also be adaptively selected according to the actual ball milling requirements. For example, 150 r / min, 170 r / min, 190 r / min, 210 r / min, or 250 r / min, etc. can be selected, and they are not listed one by one here.

[0021] Step 1.2: Load the ball-milled mixed powder into a mold with a cylindrical inner cavity. Use a hydraulic press to apply pressure to the mold containing the mixed powder. After pressing and demolding, a dense SMK alloy cylindrical bar blank is obtained. Among them, the diameter of the inner cavity cylindrical mold is Φ50mm - Φ120mm, and the length is 200mm - 800mm. The mold size can be adaptively selected within the above range according to the target size requirements of the bimetallic parts; the pressure applied by the hydraulic press: ≥500MPa per unit area; the diameter of the SMK alloy cylindrical bar blank is Φ50mm - Φ120mm, and the length is 200mm - 800mm.

[0022] Specifically, the process parameters of step 2 sintering treatment are as follows: the sintering temperature is 900°C - 1100°C, the holding time is 3h - 5h, and the heating rate is maintained between 3°C - 10°C / min.

[0023] Specifically, in step 3, the particle size range of the plasma rotating electrode method powder is 45μm - 180μm; among them, the laser particle size distribution D10: 38μm - 48μm, D50: 85μm - 110μm, D90: 160μm - 180μm.

[0024] Specifically, step 4 includes:

[0025] Step 4.1: Prepare a jacket according to the shape of the titanium alloy part and the thickness of the wear-resistant layer. There is a gap between the jacket and the titanium alloy part, and the gap is 2mm - 500mm. The gap value can be adaptively selected within the above range according to actual processing requirements. For example, it can be 2mm, 4mm, 6mm, 8mm, 10mm, 50mm, 70mm, 100mm, 200mm, 300mm, 400mm or 500mm, etc., and will not be listed one by one here;

[0026] Step 4.2: Load the screened wear-resistant metal spherical powder into the jacket and vibrate the jacket until the powder is full;

[0027] Step 4.3: Vacuumize and heat the jacket containing the wear-resistant metal spherical powder until the vacuum degree is less than or equal to ≤1.1×10 -4 Pa, and then crimp the jacket;

[0028] Step 4.4: Perform hot isostatic pressing on the crimped jacket to obtain a bimetallic part;

[0029] Step 4.5: Pickle or machine the bimetallic part to remove the jacket, and obtain the target bimetallic part with the corresponding shape and thickness.

[0030] Furthermore, in step 4.1, the grade of the titanium alloy workpiece is TC4, and its composition can meet the corresponding national standard requirements. After wrapping the titanium alloy workpiece with the said sleeve, it is welded to form a closed shell, and the whole sleeve is provided with a powder filling port and a degassing hole; wherein, the sleeve material is low-carbon steel, and its grade is 20# steel or 45# steel, and its composition and performance meet the national standard requirements, and the thickness is 2mm to 12mm; the sizes of the powder filling port and the degassing hole are both Φ5mm to Φ20mm.

[0031] It should be supplemented that the thickness of the sleeve, the sizes of the powder filling port and the degassing hole can all be adaptively selected according to actual processing requirements. For example, the thickness of the sleeve can be 2mm, 4mm, 6mm, 8mm, 10mm or 12mm, etc., and the sizes of the powder filling port and the degassing hole are 5mm, 8mm, 10mm, 12mm, 15mm, 18mm or 20mm, etc., which will not be listed one by one here.

[0032] Furthermore, in step 4.2, the vibration frequency of the said sleeve is 30Hz to 60Hz, and the vibration amplitude is 1mm to 3mm. Both can be adaptively selected according to the vibration requirements during the actual vibration process. For example, the vibration frequency is 30Hz, 40Hz, 50Hz, 60Hz, etc., and the vibration amplitude is 1mm, 2mm or 3mm, etc., which will not be listed one by one here.

[0033] Furthermore, in step 4.3, the heating temperature of the said sleeve is 400°C to 500°C, and the heat preservation time is 4h to 10h.

[0034] Furthermore, in step 4.4, the temperature used for the hot isostatic pressing treatment is 830°C to 1200°C, the pressure ≥90MPa, and the time is 3h to 4.5h.

[0035] In addition, the present invention also provides a bimetallic workpiece prepared by using the above-mentioned partial or all preparation methods, and the thickness of its cemented carbide layer is 3mm to 100mm.

[0036] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0037] 1) The wear-resistant metal alloy provided by the present invention can prepare a hard layer that meets different hardness requirements through composition regulation, and has a wide hardness regulation range. Its composition is as follows: C 2% - 8%, Si 1% - 6%, B 4% - 10%, Cr 13% - 20%. By adjusting the proportion and composition ratio of the hard precipitated phase, a hard layer with a hardness between 40 HRC and 70 HRC can be prepared. The selection of the above hardness range is based on the consideration of actual working conditions: in actual applications, for components such as titanium alloys in contact with it, it is not that the higher the hardness, the better. Excessive hardness may cause damage to other components. Therefore, it is necessary to match the hardness of the wear-resistant metal alloy with the hardness of other contact components according to actual needs.

[0038] 2) The preparation method provided by the present invention is applicable to the preparation of bimetallic parts on the surfaces of titanium alloys with different shapes. Traditional hard alloys often have too large a difference in properties from titanium alloys, and it is difficult to form a solid diffusion connection. Only by means such as spraying and remelting or adding other intermediate transition layers can a solid-solid connection be formed, resulting in poor hardness uniformity and connection strength quality of the formed bimetal. At the same time, due to process limitations, only components with simple shapes can be prepared. The preparation method provided by the present invention first prepares a specific SMK alloy electrode rod based on the wear-resistant metal alloy powder, and then prepares wear-resistant metal spherical powder based on this alloy electrode rod; then, based on the hot isostatic pressing process, bimetallic parts with wear resistance and controllable thickness on the surfaces of titanium alloys with different shapes are developed, thereby overcoming the disadvantages such as difficult preparation of complex titanium alloy shapes, thin hard layer thickness, and uneven hard layer hardness, and greatly improving the disadvantages of poor wear resistance of the titanium alloy surface and difficult preparation of the hard layer for complex parts.

[0039] 3) The preparation method provided by the present invention has the following advantages: First, due to the poor quality of traditional hard alloy powder, using the "preparation of rod + preparation of powder combination" preparation process provided by the present invention, the obtained powder has excellent uniformity, which is beneficial to the uniform organization of subsequent hot isostatic pressing; Second, adopting the forming method of "powder + special-shaped jacket + hot isostatic pressing" can meet the preparation of various shapes, and the flow filling of the powder can overcome the difficulty of large manufacturing difficulty existing in special-shaped structures. At the same time, near-net shaping is also beneficial to improving the material utilization rate and reducing the subsequent machining difficulty. Description of the Drawings

[0040] The drawings here are incorporated into the specification and form a part of this specification, and are used together with the specification to explain the principle of the present invention.

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0042] Figure 1 Flow chart of a preparation method of a bimetallic workpiece applicable to titanium alloy surfaces with different shapes provided by the present invention;

[0043] Figure 2 Microscopic morphology diagram of the wear-resistant metal alloy powder, i.e., SMK powder, provided by the present invention;

[0044] Figure 3 Cross-sectional metallographic diagram of the SMK powder provided by the present invention;

[0045] Figure 4 Morphology of the TC4-SMK alloy sample bar provided by the present invention;

[0046] Figure 5 Interface microstructure diagram of the TC4-SMK bimetallic alloy provided by the present invention;

[0047] Figure 6 TC4-SMK bimetallic alloy cone prepared in Example 1 of the present invention;

[0048] Figure 7 TC4-SMK bimetallic alloy cylinder prepared in Example 2 of the present invention;

[0049] Figure 8 TC4-SMK bimetallic alloy plate prepared in Example 3 of the present invention;

[0050] Figure 9 Point hardness distribution diagram of the bimetallic alloy cone obtained in Example 1 of the present invention at different positions from the titanium alloy surface;

[0051] Figure 10 Point hardness distribution diagram of the bimetallic alloy column obtained in Example 2 of the present invention at different positions from the titanium alloy surface;

[0052] Figure 11 Point hardness distribution diagram of the bimetallic alloy plate obtained in Example 3 of the present invention at different positions from the titanium alloy surface. Detailed implementation manners

[0053] Here, exemplary embodiments will be described in detail. The implementation manners described in the following exemplary embodiments do not represent all implementation manners consistent with the present invention. On the contrary, they are merely examples consistent with some aspects of the present invention detailed in the appended claims.

[0054] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the drawings and embodiments.

[0055] Example 1 (Conical Titanium Alloy with a Hardness of 40HRC to 45HRC)

[0056] Refer to Figure 1 , this example provides a preparation method for a bimetallic part applicable to the surface wear resistance of a conical titanium alloy with a controllable thickness. The specific preparation process is as follows:

[0057] Step 1. Prepare raw material powders according to the composition of the specified wear-resistant metal alloy (as shown in Figures 2 - 3 ), and obtain a dense SMK alloy cylindrical rod blank based on the raw material powders (as shown in Figure 4 ), specifically including:

[0058] Step 1.1. Prepare alloy powders according to the following mass percentages: 2% - 4% C powder, 1% - 3% Si powder, 4% - 6% B powder, 13% - 16% Cr powder, and the rest is Ni powder, and perform mechanical ball milling and mixing in anhydrous ethanol with a purity of 99.6%; among them, the particle sizes of C powder, Si powder, and B powder are all between 5μm and 53μm, and the particle sizes of Cr powder and Ni powder are distributed between 53 and 150μm; the diameter of the nickel-based metal balls is 7mm, the ball milling vacuum degree is 9.5×10 -4 Pa, the mixing rotation speed is 160r / min, the single mixing amount is 4kg, and the mixing time is 15h;

[0059] Step 1.2. Put the ball-milled mixed powder into a Φ63mm×600mm mold, and use a hydraulic press to apply pressure to the mold filled with the mixed powder. The applied pressure is 760MPa. After demolding, obtain a relatively dense SMK alloy cylindrical rod blank with a size of Φ63mm×600mm;

[0060] Step 2. Put the SMK alloy cylindrical rod blank into a vacuum furnace for sintering treatment to obtain an SMK alloy electrode rod. The sintering temperature is 930°C, the heat preservation time is 3.5h, the heating rate is controlled at 9.5°C / min, and after cooling, the rod is machined into a Φ62mm×595mm smooth rod;

[0061] Step 3. Use the machined Φ62mm×595mm smooth rod as an electrode rod, and prepare wear-resistant metal spherical powders by the plasma rotating electrode method, and screen them into powders with a particle size range of 45μm to 180μm. Among them, the laser particle size distribution of the powders is as follows: D10 is 45.3μm, D50 is 90.1μm, and D90 is 173.0μm;

[0062] Step 4. Based on the screened wear-resistant metal spherical powders, obtain the bimetallic part with the required shape and thickness through the process of "making a cladding → loading powder → vacuum pumping and sealing welding → hot isostatic pressing → pickling to remove the cladding", specifically including:

[0063] Step 4.1: Design and prepare a 20# steel jacket with a similar shape for a conical TC4 alloy with a bottom diameter of 300 mm and a height of 150 mm. The thickness is 3 mm. After assembly, the distance between the steel jacket and the surface of the conical titanium alloy (i.e., the gap) is 70 mm. The powder inlet of the conical steel jacket is Φ15 mm, and the degassing port is Φ8 mm;

[0064] Step 4.2: Pour the powder in the particle size range of 45 μm to 180 μm screened in Step 3 into the powder inlet of the conical steel jacket and continuously vibrate the conical steel jacket until the powder can no longer be poured in. The vibration frequency is 38 Hz, and the vibration amplitude is 3 mm;

[0065] Step 4.3: Vacuumize the jacket filled with powder in Step 4.2 and heat it to 400 °C, with a holding time of 4 h. When the vacuum degree reaches 1.0×10 -4 Pa, clamp and seal it;

[0066] Step 4.4: Perform hot isostatic pressing on the clamped and sealed jacket in Step 4.3 to obtain a bimetallic part. The hot isostatic pressing temperature is 920 °C, the pressure is 130 MPa, and the time is 3.5 h;

[0067] Step 4.5: Pickle or machine the bimetallic part to remove the jacket, and obtain a conical TC4-SMK bimetallic part with a hard layer thickness of 60 mm and a hardness of 40 HRC to 45 HRC (as Figures 5 - 6 shown).

[0068] Example 2 (Columnar titanium alloy with a hardness of 45 HRC to 50 HRC)

[0069] This example provides a preparation method for a bimetallic part suitable for wear resistance on the surface of columnar titanium alloy with a controllable thickness. The specific preparation process is as follows:

[0070] Step 1: Prepare raw material powder according to the composition of the specified wear-resistant metal alloy, and obtain a dense SMK alloy cylindrical rod blank based on the raw material powder, specifically including:

[0071] Step 1.1: Prepare powder with a total mass of 7 kg according to the following mass percentages: 4% - 5% C powder, 3% - 5% Si powder, 6% - 7% B powder, 16% - 18% Cr powder, and the rest is Ni powder, and perform mechanical ball milling and mixing in anhydrous ethanol with a purity of 99.6%; among them, the particle sizes of C powder, Si powder, and B powder are all between 5 μm and 53 μm, and the particle sizes of Cr powder and Ni powder are all distributed between 53 and 150 μm; the diameter of the nickel-based metal ball is 15 mm, the ball milling vacuum degree is 7.5×10 -4 Pa, the mixing rotation speed is 200 r / min, and the mixing time is 20 h;

[0072] Step 1.2: Put the ball-milled mixed powder into a Φ55mm×600mm mold, and use a hydraulic press to apply pressure to the mold filled with the mixed powder. The applied pressure is 650 MPa. After demolding, a relatively dense Φ55mm×600mm-sized SMK alloy cylindrical bar blank is obtained.

[0073] Step 2: Put the SMK alloy cylindrical bar blank into a vacuum furnace for sintering treatment to obtain an SMK alloy electrode bar. The sintering temperature is 950 °C, the holding time is 4.8 h, the heating rate is controlled at 6.5 °C / min. After cooling, the bar is machined into a Φ55mm×595mm smooth bar.

[0074] Step 3: Use the machined Φ55mm×595mm smooth bar as an electrode bar, and prepare wear-resistant metal spherical powder by the plasma rotating electrode method, and screen it into powder with a particle size range of 45μm - 180μm. Among them, the laser particle size distribution of the powder is as follows: D10 is 46.8μm, D50 is 95.2μm, and D90 is 179.0μm.

[0075] Step 4: Based on the screened wear-resistant metal spherical powder, a bimetallic part with the required shape and thickness is prepared through the process of "making a cladding → powder filling → vacuum pumping and sealing → hot isostatic pressing → pickling to remove the cladding", specifically including:

[0076] Step 4.1: Design and prepare a 45# steel cladding with a similar shape for a conical TC4 alloy with a bottom diameter of 50mm and a height of 150mm. The thickness is 4mm. After assembly, the distance (i.e., the gap) between the cladding and the surface of the conical titanium alloy is 110mm. The powder filling port of the conical steel cladding is Φ20mm, and the degassing port is Φ20mm.

[0077] Step 4.2: Pour the powder with a particle size range of 45μm - 180μm screened in Step 3 into the powder filling hole of the conical steel cladding and continuously vibrate the conical steel cladding until the powder no longer fills in. The vibration frequency is 55Hz, and the vibration amplitude is 1.1mm.

[0078] Step 4.3: Vacuum pump the cladding filled with powder in Step 4.2 and heat it to 450 °C, with a holding time of 7h. When the vacuum degree reaches 9.3×10 -5 Pa, clamp and seal.

[0079] Step 4.4: Perform hot isostatic pressing on the clamped and sealed cladding in Step 4.3 to obtain a bimetallic part. The hot isostatic pressing temperature is 950 °C, the pressure is 150 MPa, and the time is 4h.

[0080] Step 4.5: Pickle or machine the bimetallic part to remove the cladding, and obtain a columnar TC4-SMK bimetallic part with a hard layer thickness of 100mm and a hardness of 45HRC - 50HRC (such as Figure 7as shown).

[0081] Example 3 (plate-shaped titanium alloy with a hardness of 65HRC to 70HRC)

[0082] This example provides a preparation method for a bimetallic part suitable for wear resistance and controllable thickness on the surface of a plate-shaped titanium alloy. The specific preparation process is as follows:

[0083] Step 1: Prepare raw material powders according to the composition of the specified wear-resistant metal alloy, and obtain a dense SMK alloy cylindrical bar blank based on the raw material powders, specifically including:

[0084] Step 1.1: Prepare powders with a total mass of 5 kg according to the following mass percentages: 7% - 8% C powder, 5% - 6% Si powder, 9% - 10% B powder, 19% - 20% Cr powder, and the rest is Ni powder, and perform mechanical ball milling and mixing in anhydrous ethanol with a purity of 99.6%; among them, the particle sizes of C powder, Si powder, and B powder are all between 5μm and 53μm, and the particle sizes of Cr powder and Ni powder are distributed between 53 and 150μm; the diameter of the nickel-based metal balls is 8 mm, the ball milling vacuum degree is 5.5×10 -4 Pa, the mixing rotation speed is 250 r / min, and the mixing time is 18 h;

[0085] Step 1.2: Put the ball-milled mixed powder into a Φ70mm×600mm mold, and use a hydraulic press to apply pressure to the mold filled with the mixed powder. The applied pressure is 890 MPa. After demolding, a relatively dense Φ70mm×600mm-sized SMK alloy cylindrical bar blank is obtained;

[0086] Step 2: Put the SMK alloy cylindrical bar blank into a vacuum furnace for sintering treatment to obtain an SMK alloy electrode bar. The sintering temperature is 1100°C, the heat preservation time is 4 h, the heating rate is controlled at 3.5°C / min, and after cooling, the bar is machined into a Φ75mm×595mm optical bar;

[0087] Step 3: Use the machined Φ55mm×595mm optical bar as the electrode bar, and prepare wear-resistant metal spherical powders by the plasma rotating electrode method, and screen them into powders with a particle size range of 45μm to 180μm. Among them, the laser particle size distribution of the powders is as follows: D10 is 47.3μm, D50 is 99.5μm, and D90 is 175.0μm;

[0088] Step 4: Based on the screened wear-resistant metal spherical powders, obtain the bimetallic part with the required shape and thickness through the process of "making a jacket → loading powder → vacuum pumping and sealing → hot isostatic pressing → pickling to remove the jacket", specifically including:

[0089] Step 4.1: Design and prepare a 45# steel jacket with a similar shape for a plate-shaped TC4 alloy with a bottom surface of 200 mm (length) × 150 mm (width) × 35 mm (height). The thickness of the jacket is 5 mm. After assembly, the distance between the steel jacket and the surface of the plate-shaped titanium alloy (i.e., the gap) is 6 mm. The powder inlet of the conical steel jacket is Φ8 mm, and the degassing port is Φ8 mm;

[0090] Step 4.2: Pour the powder in the particle size range of 45 μm - 180 μm screened in Step 3 into the powder inlet of the plate-shaped steel jacket and continuously vibrate the conical steel jacket until the powder can no longer be poured in. The vibration frequency is 60 Hz, and the vibration amplitude is 1.5 mm;

[0091] Step 4.3: Vacuumize the jacket filled with powder in Step 4.2 and heat it to 500 °C. The holding time is 10 h, and the vacuum degree is 9.3×10 -5 Pa, then clamp and seal;

[0092] Step 4.4: Perform hot isostatic pressing on the clamped and sealed jacket in Step 4.3 to obtain a bimetallic part. The hot isostatic pressing temperature is 1200 °C, the pressure is 130 MPa, and the time is 4.5 h;

[0093] Step 4.5: Pickle or machine the bimetallic part to remove the jacket, and obtain a plate-shaped TC4-SMK bimetallic part with a hard layer thickness of 3 mm and a hardness of 65 HRC - 70 HRC (as Figure 8 shown).

[0094] To further verify the effectiveness of the technical solutions provided by the present invention, performance tests were specifically conducted on the bimetallic parts on the surfaces of different-shaped titanium alloys prepared in Examples 1 - 3. The test results are shown in Table 1 below:

[0095] Table 1

[0096] Example Shape Hard metal thickness / mm Hardness / HRC Bonding strength / MPa 1 Conical 60 mm 43 553 2 Columnar 100 mm 49 512 3 Plate-like 3 mm 68 563

[0097] Figure 9 This is the point hardness distribution diagram of the bimetallic alloy conical part obtained in Example 1 of the present invention at different positions from the surface of the titanium alloy; Figure 10 This is the point hardness distribution diagram of the bimetallic alloy columnar part obtained in Example 2 of the present invention at different positions from the surface of the titanium alloy; Figure 11 This is the point hardness distribution diagram of the bimetallic alloy plate-shaped part obtained in Example 3 of the present invention at different positions from the surface of the titanium alloy.

[0098] From Table 1 and Figures 9 - 11Data shows that through the preparation method provided by the present invention, cemented carbide layers with different layer thicknesses can be prepared on the surfaces of titanium alloys with different shapes. The cemented carbide layer is closely combined with the titanium alloy without adding an intermediate transition layer, which helps to solve the problem of poor wear resistance of the titanium alloy. At the same time, the cemented carbide layer can avoid the disadvantages of too thin layer thickness, insufficient diffusion bonding, and uneven hardness of the hard layer in traditional connection technologies, which is beneficial to improving the service life of titanium alloy components under wear-resistant conditions.

[0099] The above are only specific embodiments of the present invention, enabling those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention.

[0100] It should be understood that the present invention is not limited to the content already described above and can be modified and changed without departing from its scope. The scope of the present invention is only limited by the appended claims.

Claims

1. A wear-resistant metal alloy suitable for titanium alloy surfaces of different shapes, characterized in that: Calculated by mass percentage, the following components are included: C powder 2% to 8%, Si powder 1% to 6%, B powder 4% to 10%, Cr powder 13% to 20%, and the rest is Ni powder.

2. The wear-resistant metal alloy suitable for titanium alloy surfaces of different shapes according to claim 1, characterized in that: The titanium alloys of different shapes include plate-shaped titanium alloys, columnar titanium alloys or conical titanium alloys.

3. A method for preparing a bimetallic component suitable for titanium alloy surfaces of different shapes, characterized in that: The following steps are involved: Step 1, preparing raw material powder according to the composition of the wear-resistant metal alloy as claimed in claim 1 or 2, and preparing a dense SMK alloy cylindrical rod blank based on the raw material powder; Step 2, sintering the SMK alloy cylindrical rod blank to obtain an SMK alloy electrode rod; Step 3: Based on the SMK alloy electrode rod, a plasma rotating electrode method is used to prepare wear-resistant metal spherical powder, and the powder is sieved; Step 4: Based on the screened wear-resistant metal spherical powder, the target bimetallic product is obtained through the process of "making a package → filling powder → vacuuming, sealing welding → hot isostatic pressing → pickling and removing the package".

4. The method for preparing a bimetallic component suitable for titanium alloy surfaces of different shapes according to claim 3, characterized in that: The step 1 comprises: Step 1.1, mixing C powder, Si powder, B powder, Cr powder and Ni powder according to a specific mass percentage by ball milling; wherein the particle size of the C powder, Si powder and B powder is between 5 μm and 53 μm, and the particle size of the Cr powder and Ni powder is between 53 μm and 150 μm; Step 1.2: The ball-milled mixed powder is loaded into a mold with a cylindrical inner cavity, and a dense SMK alloy cylindrical rod blank is obtained after demolding by pressing.

5. The method for preparing a bimetallic component suitable for titanium alloy surfaces of different shapes according to claim 3, characterized in that: The process parameters of the sintering treatment in step 2 include: a sintering temperature of 900° C. to 1100° C., a holding time of 3 h to 5 h, and a heating rate maintained between 3° C. and 10° C. / min.

6. The method for preparing a bimetallic component suitable for titanium alloy surfaces of different shapes according to claim 3, characterized in that: The step 4 comprises: Step 4.1, preparing a sheath according to the shape of the titanium alloy workpiece and the thickness of the wear-resistant layer, leaving a gap between the sheath and the titanium alloy workpiece, and the gap is 2 mm to 500 mm; Step 4.2, placing the sieved wear-resistant metal spherical powder into the bag and vibrating the bag until the powder is full; Step 4.3: Evacuate the bag containing the metal-resistant spherical powder and heat it until the vacuum degree is less than ≤1.1×10 -4 After Pa, the package is clamped and sealed; Step 4.4, hot isostatic pressing the sealed package to obtain a bimetallic part; Step 4.5: pickling or machining the bimetallic component to remove the sheath, so as to obtain a target bimetallic component of corresponding shape and thickness.

7. The method for preparing a bimetallic component suitable for titanium alloy surfaces of different shapes according to claim 6, characterized in that: In step 4.2, the vibration frequency of the package is 30 Hz to 60 Hz, and the vibration amplitude is 1 mm to 3 mm.

8. The method for preparing a bimetallic component suitable for titanium alloy surfaces of different shapes according to claim 6, characterized in that: In step 4.3, the heating temperature of the package is 400° C. to 500° C., and the insulation time is 4 h to 10 h.

9. The method for preparing a bimetallic component suitable for titanium alloy surfaces of different shapes according to claim 6, characterized in that: In step 4.4, the hot isostatic pressing treatment is carried out at a temperature of 830° C. to 1200° C., a pressure of ≥90 MPa, and a time of 3 h to 4.5 h.

10. A bimetallic material obtained by the preparation method according to any one of claims 3 to 9 Item, characterized in that The thickness of the hard alloy layer on the surface of the bimetallic component is 3 mm to 450 mm. The hardness is 40HRC~70HRC.

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