High-entropy alloy high-temperature self-lubricating plain bearing and preparation method thereof

Abstract

This invention provides a high-entropy alloy high-temperature self-lubricating spherical plain bearing, belonging to the field of spherical plain bearing technology. The high-entropy alloy high-temperature self-lubricating spherical plain bearing includes an inner ring and an outer ring. The inner ring is made of a high-entropy alloy, and the outer ring is made of a high-temperature alloy. The outer spherical surface of the inner ring has several blind holes filled with a composite solid lubricant and a binder. The binder is aluminum chromium phosphate or zirconium silicate; the composite solid lubricant is a combination of barium fluoride, calcium fluoride, silver, hexagonal boron nitride, graphite, molybdenum disulfide, tungsten disulfide, and lead oxide. The self-lubricating spherical plain bearing provided by this invention has high reliability, excellent high-temperature load-bearing capacity and high-temperature friction and wear performance, and can be used up to 900℃. It can meet the requirements of harsh working conditions such as high temperature and heavy load, and has good application prospects in aviation, aerospace, weaponry, and equipment manufacturing.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of joint bearing, in particular to a high-entropy alloy high-temperature self-lubricating joint bearing and a preparation method thereof. BACKGROUND

[0002] The radial joint bearing is a kind of spherical sliding bearing, mainly composed of an inner ring with an outer spherical surface and an outer ring with an inner spherical surface. The joint bearing structure is simpler than the rolling bearing, without rolling body and retainer, and has larger load capacity and impact resistance. Due to the large spherical contact area, large inclination angle and automatic adjustment function, the joint bearing is mainly used for swing, tilt and rotation motion with high load but low speed. Due to the outstanding characteristics of high load capacity, self-aligning and simple structure, the joint bearing is widely used in high-tech equipment fields such as aviation, aerospace, artillery and warship, as well as conventional industrial fields such as rail transit, vehicle engineering, heavy machinery, equipment manufacturing, mining and metallurgy.

[0003] According to the different lubrication methods, the joint bearing is mainly divided into conventional joint bearing and self-lubricating joint bearing. The conventional joint bearing adopts oil lubrication or grease lubrication, and needs to be regularly added with lubricating oil or grease. The self-lubricating joint bearing belongs to a special joint bearing, and the self-lubricating mode of this kind of bearing is generally spraying a self-lubricating coating on the sliding surface, pasting a self-lubricating pad or inlaying a solid self-lubricating material. Limited by the conventional self-lubricating materials and technology, the use temperature of the self-lubricating joint bearing is below 300 DEG C, and the load capacity is low, and the service life is short, which cannot meet the application requirements of the new generation of aviation, aerospace and weapon high-tech fields in China. SUMMARY

[0004] The present application aims to provide a high-entropy alloy high-temperature self-lubricating joint bearing and a preparation method thereof, which can have good self-lubricating, wear-resistant and high load capacity performance in a high-temperature environment of up to 900 DEG C.

[0005] In order to achieve the above-mentioned application purpose, the present application provides the following technical scheme:

[0006] The present application provides a high-entropy alloy high-temperature self-lubricating joint bearing, comprising a bearing inner ring and a bearing outer ring, characterized in that the bearing inner ring is made of high-entropy alloy, the bearing outer ring is made of high-temperature alloy, the outer spherical surface of the bearing inner ring is distributed with a plurality of blind holes, the blind holes are filled with a composite solid lubricant and a bonding agent, and the bonding agent is aluminum chromium phosphate or zirconium silicate; the composite solid lubricant is multiple kinds of barium fluoride, calcium fluoride, silver, hexagonal boron nitride, graphite, molybdenum disulfide, tungsten disulfide and lead oxide.

[0007] Preferably, the high-entropy alloy is composed of metal elements, or composed of metal elements and non-metal elements, the metal elements are more than 5 of Al, Co, Cr, Fe, Ni, Mo and Ti; the non-metal elements are C, Si or B.

[0008] Preferably, the atomic molar ratio of Al, Co, Cr, Fe, Ni, Ti, Mo and non-metal elements in the high-entropy alloy is (0.1-1.1):(0.9-1.6):(0.9-1.1):(0.9-1.1):(0.9-1.1):(0-0.6):(0-0.6):(0-0.6).

[0009] Preferably, the hardness of the high-entropy alloy at room temperature is above 550 HV, the yield strength is above 1100 MPa; the hardness at high temperature of 900 DEG C is above 350 HV, the yield strength is above 600 MPa.

[0010] Preferably, the diameter of the blind hole is greater than or equal to 0.5 mm and less than 5 mm; the depth of the blind hole is greater than or equal to 0.5 mm and less than 0.5 times of the minimum wall thickness of the bearing inner ring; the total area of the blind hole is 10%-60% of the outer spherical surface area of the bearing inner ring; the distance between the centers of adjacent blind holes is less than 1.414 times of the diameter of the blind hole.

[0011] Preferably, the high-temperature alloy is cast high-temperature alloy K4951, K465 or deformed high-temperature alloy GH4141.

[0012] Preferably, the hardness of the high-temperature alloy at room temperature is higher than 350 HV, the yield strength is higher than 700 MPa; the hardness at high temperature of 900 DEG C is higher than 300 HV, the yield strength is higher than 600 MPa.

[0013] Preferably, the bearing outer ring is provided with an assembly notch, and the width of the assembly notch is greater than the width of the bearing inner ring.

[0014] The application provides a preparation method of the high-entropy alloy high-temperature self-lubricating knuckle bearing.

[0015] The high-entropy alloy is processed into a bearing inner ring, and blind holes are processed on the outer spherical surface of the bearing inner ring.

[0016] The composite solid lubricant and the binder solution are mixed, the obtained mixed slurry is injected into the blind holes, and solidification is performed to form the bearing inner ring filled with the composite solid lubricant and the binder; the binder solution is liquid aluminum chromium phosphate or zirconium silicate solution; the composite solid lubricant is multiple of barium fluoride, calcium fluoride, silver, hexagonal boron nitride, graphite, molybdenum disulfide, tungsten disulfide and lead oxide.

[0017] The high-temperature alloy is processed into a bearing outer ring.

[0018] The bearing inner ring and the bearing outer ring filled with the composite solid lubricant and the binder are assembled to obtain the high-entropy alloy high-temperature self-lubricating joint bearing.

[0019] Preferably, when the binder solution is liquid aluminum chromium phosphate, the mass ratio of the composite solid lubricant and the liquid aluminum chromium phosphate is 1: (0.5-1.6);

[0020] When the binder solution is zirconium silicate solution, the mass ratio of zirconium silicate and water in the zirconium silicate solution is 1: (1-1.5); and the mass ratio of the composite solid lubricant and the zirconium silicate solution is 1: (0.5-1.6).

[0021] The application provides a high-entropy alloy high-temperature self-lubricating joint bearing, which comprises a bearing inner ring and a bearing outer ring, the bearing inner ring is made of a high-entropy alloy, the bearing outer ring is made of a high-temperature alloy, the outer spherical surface of the bearing inner ring is provided with a plurality of blind holes, the blind holes are filled with a composite solid lubricant and a binder, and the binder is aluminum chromium phosphate or zirconium silicate; and the composite solid lubricant is multiple kinds of barium fluoride, calcium fluoride, silver, hexagonal boron nitride, graphite, molybdenum disulfide, tungsten disulfide and lead oxide.

[0022] The outer ring of the joint bearing adopts a high-temperature alloy material which has good high-temperature strength, toughness and wear resistance, and can ensure good load-carrying capacity and wear resistance under high-temperature heavy-load working conditions; the inner ring material adopts a high-entropy alloy which has good high-temperature strength and wear resistance, can ensure high-temperature load-carrying capacity and wear resistance, and can avoid adhesive wear between the inner ring material and the outer ring material under high-temperature heavy-load working conditions; in addition, the blind holes arranged on the outer spherical surface of the joint bearing inner ring have good storage and supply effects on the solid lubricant, can ensure that the solid lubricant is continuously supplied on the friction interface during high-temperature friction, and thus good high-temperature friction reduction and lubrication effects are achieved; the composite solid lubricant filled in the blind holes of the outer spherical surface of the joint bearing inner ring has good high-temperature resistance and high-temperature self-lubrication, the high-temperature resistance and high-temperature self-lubrication of the composite solid lubricant formed by compounding different kinds of high-temperature resistant solid lubricants are better than those of a single lubricant, and the composite solid lubricant can still have good self-lubrication effects in a high-temperature environment of up to 900 DEG C; finally, the binder adopted by the application has good high-temperature bonding effects, the aluminum chromium phosphate can be used in a high-temperature environment of up to 1200 DEG C after solidification, the zirconium silicate (ZrSiO4) can be used in a high-temperature environment of up to 1400 DEG C after solidification, and the two kinds of binders have low solidification temperatures, good bonding effects and can ensure that the composite solid lubricant will not fall off during use.

[0023] Due to the above reasons, the high-entropy alloy high-temperature self-lubricating knuckle bearing disclosed by the application can be used in a high-temperature environment of up to 900 DEG C, and has good high-temperature self-lubricating, wear resistance, high load bearing and high reliability, and other excellent performances, thereby breaking through the technical bottleneck that the maximum service temperature of the conventional self-lubricating knuckle bearing is lower than 300 DEG C. The knuckle bearing provided by the application can be applied to equipment serving in high-temperature environments in the fields of aerospace, weapons, metallurgy, chemical industry, kiln and equipment manufacturing. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 Fig. 1 is a schematic diagram of the inner ring structure, the outer ring structure and the knuckle bearing assembly of the high-entropy alloy high-temperature self-lubricating knuckle bearing;

[0025] Figure 2 Fig. 2 is a structural diagram of the UC15 type knuckle bearing in Example 1;

[0026] Figure 3 Fig. 3 is a schematic diagram of the size and distribution of the blind holes on the outer spherical surface of the inner ring of the UC15 type knuckle bearing in Example 1;

[0027] Figure 4 Fig. 4 is a structural diagram of the UC8 type knuckle bearing in Example 2;

[0028] Figure 5 Fig. 5 is a structural diagram of the GE20E type knuckle bearing in Example 3. DETAILED DESCRIPTION

[0029] As shown in Figure 1 , the application provides a high-entropy alloy high-temperature self-lubricating knuckle bearing, which comprises a bearing inner ring and a bearing outer ring, the bearing inner ring is made of high-entropy alloy, the bearing outer ring is made of high-temperature alloy, a plurality of blind holes are distributed on the outer spherical surface of the bearing inner ring, the blind holes are filled with a composite solid lubricant and a binder, the binder is aluminum chromium phosphate or zirconium silicate, and the composite solid lubricant is a plurality of barium fluoride, calcium fluoride, silver, hexagonal boron nitride, graphite, molybdenum disulfide, tungsten disulfide and lead oxide.

[0030] The high-entropy alloy high-temperature self-lubricating spherical plain bearing provided by this invention includes an inner ring. In this invention, the inner ring is made of a high-entropy alloy, preferably composed of metallic elements, or of metallic and non-metallic elements. The metallic elements are preferably five or more selected from Al, Co, Cr, Fe, Ni, Mo, and Ti, and more preferably must contain Al, Co, Cr, Fe, and Ni. The non-metallic elements are preferably C, Si, or B. In this invention, the preferred atomic molar ratio of Al, Co, Cr, Fe, Ni, Ti, Mo, and non-metallic elements in the high-entropy alloy is (0.1~1.1):(0.9~1.6):(0.9~1.1):(0.9~1.1):(0.9~1.6):(0~0.6):(0~0.6):(0~0.6). In an embodiment of this invention, the high-entropy alloy is specifically AlCoCrFeNiMo. 0.25 C 0.2 Al 0.2 Co 1.5 CrFeNi 1.5 Ti 0.5 Si 0.1 Or Al 0.2 Co 1.5 CrFeNi 1.5 Ti 0.5 B 0.2 .

[0031] In this invention, the high-entropy alloy preferably has a room temperature hardness of 550 HV or higher and a yield strength of 1100 MPa or higher; at a high temperature of 900°C, its hardness is preferably 350 HV or higher and its yield strength is preferably 600 MPa or higher. The bearing inner ring material of this invention uses a high-entropy alloy with good high-temperature strength and wear resistance, which ensures its high-temperature load-bearing capacity and wear resistance, and avoids adhesive wear between the inner ring material and the outer ring material under high-temperature heavy-load conditions. This invention does not impose special requirements on the dimensions of the bearing inner ring; those skilled in the art can select the appropriate dimensions based on actual needs.

[0032] In this invention, the outer spherical surface of the inner ring of the bearing is provided with a plurality of blind holes.

[0033] In the application, the diameter of the blind hole is preferably ≥0.5mm and <5mm, more preferably 0.5-4mm, further preferably 1-2mm; the depth of the blind hole is preferably ≥0.5mm and <0.5 times the minimum wall thickness of the bearing inner ring, more preferably 0.5-1.5mm; the total area of the blind hole is preferably 10%-60% of the outer spherical surface area of the bearing inner ring, more preferably 15-60%, further preferably 20-40%; the distance between the centers of adjacent blind holes is preferably less than 1.414 times the diameter of the blind hole. The blind holes opened on the outer spherical surface of the joint bearing inner ring have good storage and supply effects on the solid lubricant, and can ensure that the solid lubricant is continuously supplied to the friction interface during high-temperature friction, thereby achieving good high-temperature friction reduction and lubrication effects.

[0034] In the application, the blind hole is filled with a composite solid lubricant and a binder. In the application, the composite solid lubricant is a plurality of barium fluoride, calcium fluoride, silver, hexagonal boron nitride, graphite, molybdenum disulfide, tungsten disulfide and lead oxide, preferably a mixture of graphite, tungsten disulfide and lead oxide, or a mixture of barium fluoride, calcium fluoride and silver, or a mixture of graphite, molybdenum disulfide and hexagonal boron nitride. The application does not have special requirements for the ratio of each solid lubricant. In the application, when the composite solid lubricant is a mixture of graphite, tungsten disulfide and lead oxide, the mass percentage of graphite, tungsten disulfide and lead oxide is 60%:20%:20%; when the composite solid lubricant is a mixture of barium fluoride, calcium fluoride and silver, the barium fluoride and calcium fluoride are preferably used in the form of eutectic fluoride; the eutectic component has a mass percentage of BaF2:CaF2=62%:38%; the mass percentage of the eutectic fluoride and silver is preferably 50%:50%. When the composite solid lubricant is a mixture of graphite, molybdenum disulfide and hexagonal boron nitride, the mass percentage of graphite, molybdenum disulfide and hexagonal boron nitride is preferably 40%:30%:30%. The composite solid lubricant filled in the blind hole of the outer spherical surface of the joint bearing inner ring has good high-temperature resistance and high-temperature self-lubrication performance, and the composite solid lubricant formed by compounding different types of high-temperature resistant solid lubricants has better high-temperature resistance and high-temperature self-lubrication performance than a single lubricant, which can ensure that it still has good self-lubrication effect in a high-temperature environment of up to 900℃.

[0035] In the application, the binder is aluminum chromium phosphate or zirconium silicate. The binder used in the application has good high-temperature bonding effect, in which the aluminum chromium phosphate can be used in a high-temperature environment of up to 1200℃ after solidification, and the ZrSiO4 can be used in a high-temperature environment of up to 1400℃ after solidification, and the two binders have low solidification temperature and good bonding effect, and can ensure that the composite solid lubricant does not fall off during use after solidification.

[0036] The ratio of the binder and the composite solid lubricant is determined by the preparation method, which will be described in detail later.

[0037] The high-entropy alloy high-temperature self-lubricating knuckle bearing provided by the application comprises a bearing outer ring, and the bearing outer ring is made of a high-temperature alloy. In the application, the high-temperature alloy is preferably cast high-temperature alloy K4951, K465 or wrought high-temperature alloy GH4141. In the application, the high-temperature alloy has a hardness higher than 350 HV and a yield strength higher than 700 MPa at room temperature, and has a hardness higher than 300 HV and a yield strength higher than 600 MPa at 900 DEG C. The outer ring of the knuckle bearing in the application adopts a high-temperature alloy material with high strength and toughness and good wear resistance, which can ensure good load-carrying capacity and wear resistance under high-temperature and heavy-load working conditions. In the application, the bearing outer ring is preferably provided with an assembly notch, and the width of the assembly notch is preferably greater than the width of the bearing inner ring. During assembly, the bearing inner ring is first inserted into the outer ring through the notch of the outer ring, and then the bearing inner ring is turned back by 90 DEG to form the knuckle bearing. Since the knuckle bearing applied in a high-temperature environment is prone to serious deformation and fracture under heavy load, in order to ensure the reliability and safety of the knuckle bearing, the application adopts an integral knuckle bearing outer ring, and an assembly notch is formed at the edge of the outer ring, and the bearing inner ring is inserted into the outer ring to form the knuckle bearing.

[0038] The application provides a preparation method of the high-entropy alloy high-temperature self-lubricating knuckle bearing.

[0039] The high-entropy alloy is processed into a bearing inner ring, and a blind hole is processed on the outer spherical surface of the bearing inner ring;

[0040] The composite solid lubricant and the binder solution are mixed, the obtained mixed slurry is injected into the blind hole, and the mixed slurry is solidified to form the bearing inner ring filled with the composite solid lubricant and the binder; the binder solution is a liquid aluminum chromium phosphate or zirconium silicate solution; the composite solid lubricant is multiple kinds of barium fluoride, calcium fluoride, silver, hexagonal boron nitride, graphite, molybdenum disulfide, tungsten disulfide and lead oxide;

[0041] The high-temperature alloy is processed into a bearing outer ring;

[0042] The bearing inner ring filled with the composite solid lubricant and the binder and the bearing outer ring are assembled to obtain the high-entropy alloy high-temperature self-lubricating knuckle bearing.

[0043] In the application, the raw materials used are all commercially available goods well known in the art, unless otherwise specified.

[0044] The high-entropy alloy is first processed into a bearing inner ring, and a blind hole is processed on the outer spherical surface of the bearing inner ring. The high-entropy alloy has no special requirements on the source, and can be obtained by using commercially available products or methods known to those skilled in the art. In the present application, it is preferably prepared by itself. The preparation method of the high-entropy alloy preferably comprises the following steps: sequentially melting and pouring each preparation raw material to obtain a high-entropy alloy. In the present application, the number of melting is preferably more than 6 times, so as to ensure uniform distribution of each element. The present application has no special requirements for the way of melting, which can be arc melting or induction melting. The present application has no special requirements for the way of pouring, which can be poured by using water-cooled copper mold or graphite mold. The present application has no special requirements for the processing method of the bearing inner ring, which can be processed by using the processing method known to those skilled in the art.

[0045] After the bearing inner ring is processed, a blind hole is processed on the outer spherical surface of the bearing inner ring. The present application has no special requirements for the processing method of the blind hole, which can obtain a required blind hole.

[0046] The composite solid lubricant and the binder solution are mixed in the present application, the obtained mixed slurry is injected into the blind hole, and solidified to form a bearing inner ring filled with composite solid lubricant and binder.

[0047] In the present application, the composite solid lubricant is a plurality of barium fluoride, calcium fluoride, silver, hexagonal boron nitride, graphite, molybdenum disulfide, tungsten disulfide and lead oxide; the particle size of the composite solid lubricant is preferably less than 50 microns. In the present application, the binder solution is a liquid aluminum chromium phosphate or zirconium silicate solution.

[0048] When the binder solution is a liquid aluminum chromium phosphate, the mass ratio of the composite solid lubricant to the liquid aluminum chromium phosphate is preferably 1: (0.5-1.6); when the binder solution is a zirconium silicate solution, the mass ratio of zirconium silicate to water in the zirconium silicate solution is preferably 1: (1-1.5); the mass ratio of the composite solid lubricant to the zirconium silicate solution is preferably 1: (0.5-1.6).

[0049] The present application has no special requirements for the way of mixing the composite solid lubricant and the binder solution, which can be mixed uniformly by using the way known to those skilled in the art. In the embodiment of the present application, it is specifically performed in a planetary ball mill.

[0050] After the mixed slurry is obtained, the mixed slurry is injected into the blind hole, solidified to form the bearing inner ring filled with the composite solid lubricant and the binder. The present application preferably fills the blind hole. In the present application, when the binder solution is the liquid aluminum chromium phosphate, the solidification temperature is preferably 300-350°C. When the binder solution is the zirconium silicate solution, the solidification temperature is preferably 70-90°C. The present application does not have special requirements for the solidification time, and the solidification is removed after solidification.

[0051] The high-temperature alloy is processed into the bearing outer ring in the present application.

[0052] The present application does not have special requirements for the processing method of the bearing outer ring, and the processing method known in the art can be used. The outer ring shape and the notch are processed in the processing process in the present application. In the present application, in order to meet the mechanical property requirements of the high-temperature alloy, the high-temperature alloy is preferably processed into an outer ring blank first, then solid solution and aging treatment are carried out, and finally precision grinding is carried out to obtain the required bearing outer ring. The present application does not have special requirements for the conditions of the solid solution and aging treatment, and the solid solution and aging treatment conditions known in the art can be used.

[0053] After the bearing inner ring and the bearing outer ring filled with the composite solid lubricant and the binder are obtained, the bearing inner ring and the bearing outer ring filled with the composite solid lubricant and the binder are preferably assembled to obtain the high-entropy alloy high-temperature self-lubricating knuckle bearing. During assembly, the bearing inner ring is first inserted into the outer ring through the outer ring notch, and then turned back 90° to form a knuckle bearing.

[0054] The high-entropy alloy high-temperature self-lubricating knuckle bearing and the preparation method thereof provided by the present application will be described in detail below in conjunction with the examples, but they should not be understood as limiting the scope of protection of the present application.

[0055] Example 1

[0056] The high-entropy alloy high-temperature self-lubricating knuckle bearing disclosed in this example is a UC15 knuckle bearing, the inner diameter of the bearing inner ring is 15 mm, the outer diameter of the bearing outer ring is 28 mm, the sliding spherical diameter between the inner / outer rings is 23 mm, and the remaining dimensions and structural diagram of the bearing are shown in Figure 2 .

[0057] The bearing inner ring is made of AlCoCrFeNiMo 0.25 C 0.2High-entropy alloy manufacturing. The high-entropy alloy is first prepared into an alloy ingot with uniform composition and structure by using conventional arc melting technology, and the alloy is melted for at least 6 times to ensure uniform distribution of each element in the alloy. Then the high-entropy alloy rod with a diameter of Φ25mm and a length of 50mm is cast in a water-cooled copper mold. The mechanical properties of the high-entropy alloy rod at room temperature and 900℃, such as hardness and yield strength, are shown in Table 1.

[0058] Table 1 AlCoCrFeNiMo 0.25 C 0.2 Mechanical properties of high-entropy alloy materials

[0059]

[0060] The cast high-entropy alloy rod is machined into a bearing inner ring, and then a blind hole with a diameter of 1mm and a depth of 1mm is machined on the outer spherical surface of the inner ring. A total of 264 blind holes are uniformly distributed around the center of the outer spherical surface of the inner ring (as shown in Figure 3 The area of the outer spherical surface of the inner ring occupied by the blind holes is 23.9%, and the distance between the nearest two adjacent blind holes is 1.3mm.

[0061] The composite solid lubricant is a mixture of barium fluoride, calcium fluoride and silver powder. The barium fluoride and calcium fluoride are in the form of eutectic powder (mass percentage BaF2: CaF2= 62%: 38%), and the mass percentage of eutectic fluoride is 50%. The mass percentage of silver powder is also 50%. The particle size of the solid lubricant is less than 50 microns. The binder is liquid aluminum phosphate, and the mass ratio of the composite solid lubricant to the liquid aluminum phosphate chromium is 1:0.5. After mixing the composite solid lubricant powder with the binder, the mixture is ball milled for 5 hours by using a planetary ball mill to form a solid lubricant slurry. Then, the solid lubricant slurry is injected and filled into the blind holes of the inner ring of the joint bearing. After completely filling the blind holes, the solid lubricant is solidified at 300℃ in a muffle furnace for 5 hours, and finally the solid lubricant and the binder are solidified and filled in the blind holes.

[0062] The outer ring of the joint bearing is made of GH4141 high-temperature alloy. The high-temperature alloy is machined into a joint bearing outer ring blank, and then heat treated by solid solution treatment and aging treatment to control its mechanical properties such as hardness and strength. After heat treatment, the hardness of the outer ring at room temperature is 377HV, and the yield strength is 1080MPa. At 900℃, the hardness is 310HV, and the yield strength is 690MPa. Finally, the outer ring is precisely ground to the final size to form the finished joint bearing outer ring. Then, the inner ring and the outer ring manufactured by the above method are assembled to form a joint bearing product.

[0063] The friction and wear properties of the bearing sample under different temperatures of room temperature, 400°C, 700°C and 900°C were tested by using a high-temperature spherical plain bearing testing machine under the conditions of atmospheric environment, radial load 8000N, swing angle ±25 degrees, frequency 2Hz, and test time 2 hours. The test results are shown in Table 2. The test shows that the spherical plain bearing can be stably operated for 2 hours under the above test conditions, and the friction coefficient and wear amount still meet the use requirements (the maximum wear depth is less than 0.150mm).

[0064] Table 2 Friction and wear properties of high-entropy alloy high-temperature self-lubricating spherical plain bearing of UC15 type

[0065]

[0066] Note: The spherical plain bearing is swinging, and the friction coefficient is positive and negative, so it is a range.

[0067] Example 2

[0068] The high-entropy alloy high-temperature self-lubricating spherical plain bearing disclosed in this example is a UC8 spherical plain bearing. The inner diameter of the inner ring of the spherical plain bearing is 8mm, the outer diameter of the outer ring is 17mm, and the sliding spherical surface diameter between the inner / outer rings is 13mm. The rest of the size and structure diagram of the bearing are shown in Figure 4 .

[0069] The inner ring of the spherical plain bearing is made of Al 0.2 Co 1.5 CrFeNi 1.5 Ti 0.5 Si 0.1 high-entropy alloy. The high-entropy alloy is prepared by induction melting technology. After melting, it is cast into a high-entropy alloy bar with a diameter of Φ15mm and a length of 40mm. The hardness and yield strength and other mechanical properties of the high-entropy alloy at room temperature and 900°C are tested and shown in Table 3.

[0070] Table 3 Mechanical properties of Al 0.2 Co 1.5 CrFeNi 1.5 Ti 0.5 Si 0.1 high-entropy alloy material

[0071]

[0072] The high-entropy alloy bar is machined to manufacture the bearing inner ring, and then the Figure 3The distribution rule is shown, a blind hole with a diameter of 0.5 mm is machined on the outer spherical surface of the inner ring by laser processing, the blind hole has a depth of 0.5 mm, 264 blind holes are uniformly distributed around the center of the sphere on the outer spherical surface of the inner ring, the area of the blind holes on the outer spherical surface of the inner ring is 15.8%, and the distance between the two adjacent blind holes closest to each other is 0.7 mm.

[0073] The composite solid lubricant is a mixture of graphite, molybdenum disulfide and hexagonal boron nitride powder, the particle size of the solid lubricant is less than 30 microns, and the mass percentage of graphite, molybdenum disulfide and hexagonal boron nitride is 40:30:30. The binder is a ZrSiO4 aqueous solution (mass percentage of ZrSiO4: deionized water = 1:1.5), the solid lubricant and the binder solution are mixed according to the mass percentage of 1:0.5, and the planetary ball mill is used for ball milling for 6 hours to form the solid lubricant slurry. Then, the composite solid lubricant slurry is injected and filled into the blind hole of the inner ring of the spherical bearing, and after being placed in an oven at 80°C for 24 hours, the solid lubricant and the binder are completely solidified and filled into the blind hole of the inner ring of the spherical bearing.

[0074] The outer ring of the spherical bearing is made of K4951 high-temperature alloy, which is machined into a spherical bearing outer ring blank, and then the mechanical properties such as hardness and strength are controlled by heat treatment methods such as solid solution treatment and aging treatment. After heat treatment, the hardness at room temperature is 386HV, the yield strength is 1120MPa, the hardness at 900°C is 330HV, and the yield strength is 710MPa. Finally, the final size is achieved by precision grinding to form the finished product of the outer ring of the spherical bearing. The inner ring and the outer ring manufactured by the above process are assembled to form the spherical bearing product.

[0075] The high-temperature spherical bearing tester is used to test the friction and wear properties of the bearing sample at different temperatures of room temperature, 400°C, 700°C and 900°C under the conditions of atmospheric environment, radial load of 2000N, swing angle of ±25 degrees, frequency of 2Hz and test time of 2 hours. The test results are shown in Table 4. The test shows that the spherical bearing can stably run for 2 hours under the above test conditions, and the friction coefficient and wear amount still meet the use requirements.

[0076] Table 4 Friction and wear properties of UC8 high-entropy alloy high-temperature self-lubricating spherical bearing

[0077]

[0078] Example 3

[0079] The high-entropy alloy high-temperature self-lubricating knuckle bearing disclosed in the embodiment has a structure similar to that of a GE20E knuckle bearing. The inner diameter of the inner ring of the knuckle bearing is 20 mm, the outer diameter of the outer ring is 35 mm, the sliding spherical diameter between the inner ring and the outer ring is 28 mm, and the rest of the size and structure of the bearing are as shown in Figure 5 .

[0080] The inner ring of the knuckle bearing is made of Al 0.2 Co 1.5 CrFeNi 1.5 Ti 0.5 B 0.2 high-entropy alloy. The high-entropy alloy is prepared by vacuum arc melting technology. The alloy is melted at least 6 times to ensure uniform distribution of elements in the alloy, and then cast into a Φ30mm×60mm high-entropy alloy bar in a water-cooled copper mold. The hardness and yield strength of the high-entropy alloy at room temperature and 900°C are tested, and the mechanical properties are shown in Table 5.

[0081] Table 5 Al 0.2 Co 1.5 CrFeNi 1.5 Ti 0.5 B 0.2 Mechanical properties of high-entropy alloy material

[0082]

[0083] The high-entropy alloy bar is machined to manufacture the inner ring of the bearing, and then a five-axis linkage numerical control machining center is used to machine a blind hole with a diameter of 2 mm on the outer spherical surface of the inner ring according to the distribution shown in Figure 3 . The depth of the blind hole is 1.5 mm. A total of 264 blind holes are machined on the outer spherical surface of the inner ring around the spherical center in a uniform array distribution manner. The area of the blind holes on the outer spherical surface of the inner ring is 59%, and the distance between the nearest two adjacent blind holes is 2.8 mm.

[0084] The composite solid lubricant is a mixture of graphite, tungsten disulfide and lead oxide, and the mass percentage of the three is 60%:20%:20%. The particle size of the solid lubricant is less than 20 microns. The binder is an aluminum chromium phosphate solution, and the mass ratio of the solid lubricant to the aluminum chromium phosphate solution is 1:1.5. After mixing the composite solid lubricant powder and the binder solution, the planetary ball mill is used to mix and grind for 12 hours to form a solid lubricant slurry. Then, the solid lubricant slurry is injected and filled into the blind holes of the inner ring of the knuckle bearing. After solidification at 300°C for 2 hours, the solid lubricant and the binder are completely solidified and finally filled into the blind holes of the inner ring of the knuckle bearing.

[0085] The outer ring of the spherical plain bearing is made of cast high-temperature alloy K465. This alloy is machined into a blank, and then its hardness and strength are controlled through heat treatment methods such as solution treatment and aging treatment. After heat treatment, its room temperature hardness is 390 HV, and its yield strength is ≥920 MPa; at 900℃, its hardness is 340 HV, and its yield strength is ≥770 MPa. Finally, precision grinding is performed to achieve the final dimensions, forming the finished outer ring of the spherical plain bearing. The inner and outer rings, after being machined and manufactured as described above, are assembled to form the spherical plain bearing product.

[0086] The friction and wear performance of the bearing sample was tested using a high-temperature spherical plain bearing testing machine under atmospheric conditions, with a radial load of 10000 N, a swing angle of ±25 degrees, a frequency of 2 Hz, and a test time of 2 hours, at different temperatures of room temperature, 400℃, 700℃, and 900℃. The test results are shown in Table 6. The test results show that the spherical plain bearing can still meet the usage requirements in terms of friction coefficient and wear after stable operation for 2 hours under the above test conditions.

[0087] Table 6. Friction and wear properties of GE20E type high-entropy alloy high-temperature self-lubricating spherical plain bearings

[0088]

[0089] Comparative example:

[0090] This comparative example provides a spherical bearing with the exact same structure as Example 1. Through direct comparison and analysis with Example 1, the superiority or inferiority of the various performance characteristics of the high-entropy alloy high-temperature self-lubricating spherical bearing prepared by the technical solution disclosed in this invention can be intuitively observed.

[0091] In this comparative example, the structural dimensions of each part of the spherical bearing are exactly the same as those in Example 1 (e.g., ...). Figure 2 As shown, the outer ring material (GH4141 high-temperature alloy) and manufacturing method of the comparative spherical plain bearing are exactly the same as those of Example 1. However, the inner ring material of the comparative spherical plain bearing is made of cast high-temperature alloy K4951, and there are no blind holes or solid lubricants filled on the inner ring. In order to achieve high-temperature lubrication, a layer of solid lubricant slurry is coated on the outer spherical surface of the inner ring of the bearing and then cured. The formulation of the solid lubricant slurry and its curing method are exactly the same as those of Example 1.

[0092] In the manufacture of the inner ring of the knuckle bearing, first, the K4951 high-temperature alloy is manufactured into a knuckle bearing inner ring blank by machining, and then the mechanical properties such as hardness and strength are controlled by heat treatment methods such as solid solution treatment and aging treatment. After heat treatment, the hardness at room temperature is 386HV, the yield strength is 1120MPa, the hardness at 900℃ high temperature is 330HV, and the yield strength is 710MPa. Finally, the final size is achieved by precision grinding to form the inner ring product of the knuckle bearing. Then the solid lubricant slurry given in Example 1 is coated on the outer spherical surface of the inner ring, and the coating thickness is about 15 microns. After coating, it is solidified, and the solidification process is exactly the same as that in Example 1.

[0093] The knuckle bearing outer ring made of GH4141 high-temperature alloy material is assembled with the knuckle bearing inner ring made of K4951 high-temperature alloy material to form a comparative example knuckle bearing. The friction and wear properties of the bearing sample are tested by using a high-temperature knuckle bearing tester under the same conditions as Example 1 (in an atmospheric environment, radial load 8000N, swing angle ±25 degrees, frequency 2Hz, test time 2 hours, test temperature room temperature, 400℃, 700℃ and 900℃). The test results are shown in Table 7.

[0094] Table 7 Friction and wear properties of the comparative example UC15 type high-temperature knuckle bearing

[0095]

[0096] By comparing Table 2 in Example 1 of the present application and Table 7 in the comparative example, it can be seen that the friction coefficient of the knuckle bearing in the comparative example is significantly higher than that of the knuckle bearing in Example 1 at room temperature and 400℃, and the wear amount is extremely large, reaching 0.154mm and 0.187mm respectively, indicating that it cannot meet the use requirements under this test condition. When tested above 700℃, due to the lack of effective lubrication between the inner and outer rings, and the composition of the two is similar, welding occurs during high-temperature friction, and the bearing is completely failed. Therefore, the high-temperature self-lubricating knuckle bearing manufactured by the technical scheme provided in the present application has high reliability, excellent high-temperature load capacity and high-temperature friction and wear properties, and can meet the use requirements under harsh working conditions such as high temperature and heavy load, and has good application prospect in the fields of aviation, aerospace, weapons and equipment manufacturing.

[0097] The above only describes the preferred embodiments of the present application, and it should be noted that for ordinary skilled persons in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A high-entropy alloy high-temperature self-lubricating plain bearing comprising a bearing inner ring and a bearing outer ring, characterized in that The bearing inner ring is made of high-entropy alloy, the bearing outer ring is made of high-temperature alloy, the outer spherical surface of the bearing inner ring is distributed with a plurality of blind holes, the blind holes are filled with composite solid lubricant and binder, the binder is aluminum chromium phosphate or zirconium silicate, and the composite solid lubricant is a plurality of barium fluoride, calcium fluoride, silver, hexagonal boron nitride, graphite, molybdenum disulfide, tungsten disulfide and lead oxide. The high-entropy alloy is composed of metal elements or metal elements and non-metal elements, the metal elements are more than 5 of Al, Co, Cr, Fe, Ni, Mo and Ti, and the non-metal elements are C, Si or B. The atomic molar ratio of Al, Co, Cr, Fe, Ni, Ti, Mo and non-metal elements in the high-entropy alloy is (0.1-1.1):(0.9-1.6):(0.9-1.1):(0.9-1.1):(0.9-1.1):(0-0.6):(0-0.6):(0-0.6). The diameter of the blind hole is ≥0.5mm and <5mm, the depth of the blind hole is ≥0.5mm and <0.5 times of the minimum wall thickness of the bearing inner ring, the total area of the blind hole is 10%-60% of the outer spherical surface area of the bearing inner ring, and the distance between the centers of adjacent blind holes is less than 1.414 times of the diameter of the blind hole.

2. The high-entropy alloy high-temperature self-lubricating plain bearing according to claim 1, characterized in that The hardness of the high-entropy alloy at room temperature is above 550HV, and the yield strength is above 1100MPa; the hardness at high temperature of 900℃ is above 350HV, and the yield strength is above 600MPa.

3. The high-entropy alloy high-temperature self-lubricating plain bearing according to claim 1, characterized in that The high-temperature alloy is cast high-temperature alloy K4951, K465 or deformed high-temperature alloy GH4141.

4. The high-entropy alloy high-temperature self-lubricating plain bearing according to claim 1 or 3, characterized in that The hardness of the high-temperature alloy at room temperature is above 350HV, and the yield strength is above 700MPa; the hardness at high temperature of 900℃ is above 300HV, and the yield strength is above 600MPa.

5. The high-entropy alloy high-temperature self-lubricating plain bearing according to claim 1, characterized in that The bearing outer ring is provided with an assembly notch, and the width of the assembly notch is greater than the width of the bearing inner ring.

6. A preparation method of the high-entropy alloy high-temperature self-lubricating plain bearing according to any one of claims 1-5, comprising the following steps: processing the high-entropy alloy into a bearing inner ring and processing blind holes on the outer spherical surface of the bearing inner ring; mixing the composite solid lubricant and the binder solution, injecting the obtained mixed slurry into the blind holes, and solidifying to form the bearing inner ring filled with the composite solid lubricant and the binder; the binder solution is liquid aluminum chromium phosphate or zirconium silicate solution; the composite solid lubricant is a plurality of barium fluoride, calcium fluoride, silver, hexagonal boron nitride, graphite, molybdenum disulfide, tungsten disulfide and lead oxide; processing the high-temperature alloy into a bearing outer ring; assembling the bearing inner ring filled with the composite solid lubricant and the binder and the bearing outer ring to obtain the high-entropy alloy high-temperature self-lubricating plain bearing.

7. The preparation method according to claim 6, characterized in that, When the binder solution is liquid aluminum chromium phosphate, the mass ratio of the composite solid lubricant to the liquid aluminum chromium phosphate is 1:(0.5-1.6); When the binder solution is zirconium silicate solution, the mass ratio of zirconium silicate to water in the zirconium silicate solution is 1:(1-1.5); and the mass ratio of the composite solid lubricant to the zirconium silicate solution is 1:(0.5-1.6).

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