A friction stir welding tool and a method of manufacturing the same

Abstract

The application provides a friction stir welding tool and a preparation method thereof, and a gradient tungsten alloy material and a preparation method thereof. The friction stir welding tool comprises a clamping part, a tool shoulder and a tool pin tip part, two ends of the tool shoulder are connected with the clamping part and the tool pin tip part respectively, the clamping part, the tool shoulder and the tool pin tip part are all prepared from a tungsten-rhenium alloy, and the tungsten content in the tungsten-rhenium alloy of the clamping part, the tool shoulder and the tool pin tip part decreases in turn. According to the component gradient change of the pure tungsten-rhenium tool, different components are prepared according to the performance requirements of different parts, so that the service life of the tool material is effectively improved, and the material cost is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of gradient material preparation, in particular to a stir friction welding stir head and a preparation method thereof, and a gradient tungsten alloy material and a preparation method thereof. BACKGROUND

[0002] Gradient material is a kind of inhomogeneous composite material with continuous or quasi-continuous change in composition, structure or performance in space. Its core feature is to realize the optimal combination of different regional functions through gradient design in the material, so as to solve the problem that traditional homogeneous materials cannot meet multiple performance requirements. Gradient materials are widely used in the fields of aerospace, medical health, biomedical engineering, electronics and semiconductors, friction stir welding, nanotechnology and smart materials, and have high application value in small-size rotating anode target discs for electron tubes and stir heads for friction stir welding.

[0003] Tungsten has high melting point, high density, good thermal conductivity and high elastic modulus, but has disadvantages such as low-temperature brittleness, high ductile-brittle transition temperature (DBTT) and recrystallization brittleness. The performance can be improved by solid solution strengthening, fine grain strengthening and dispersion strengthening, etc. Typical solid solution strengthening method is to add metal rhenium. Compared with pure tungsten, WRe alloy has better high-temperature resistance, ductility, low vapor pressure, low electron work function and low ductile-brittle transition temperature. The alloy performance is different with different proportions of Re content. The yield strength of WRe alloy at room temperature is the smallest when the Re content is 7%, and the fracture toughness is the largest. The grain refinement in W10Re is particularly obvious, which can improve the strength and thermal shock resistance of the material. Therefore, according to different application scenarios, designing gradient materials with different compositions is beneficial to improve the performance and service life of the materials.

[0004] At present, the rotating anode target disc for small-size electron tubes is mostly pure W target, which is not conducive to the processing of the target surface, and the target surface is easily damaged by the continuous bombardment of high-energy electron beams, resulting in thermal cracks and failure of the electron tube. The high-hardness and high-melting-point stir head for friction stir welding is composed of tungsten-rhenium alloy with consistent composition, which has high material cost and is not conducive to the popularization and application of the material. In order to improve the performance of the material and the service life of the part, gradient materials with different compositions are prepared to adapt to the use of special environment. There are few reports on the preparation and research of tungsten alloy gradient materials.

[0005] Therefore, the preparation and research of tungsten alloy gradient materials can help to solve the shortcomings of single materials in different environments. SUMMARY

[0006] TECHNICAL PROBLEM

[0007] In view of the problems and deficiencies in the prior art, the present application provides a stir head for friction stir welding and a preparation method thereof, and a gradient tungsten alloy material and a preparation method thereof. By designing a tungsten alloy material with different component gradients, i.e. adding different components or contents of additives to tungsten, the shortcomings and deficiencies of the tungsten material itself are overcome or improved, the prepared gradient material has better performance and service life, the material cost is effectively reduced, and the application of the gradient material is further improved.

[0008] Technical scheme

[0009] According to a first aspect of the present application, a SPS method for preparing a gradient tungsten alloy material is provided, which comprises the following steps:

[0010] Step 1: a plurality of tungsten alloy powders with different tungsten contents, and / or a plurality of powder mixtures of metal tungsten powder and other metal powders and optional metal oxide powders are respectively prepared and uniformly mixed, and then dried;

[0011] Step 2: the plurality of tungsten alloy powders with different tungsten contents, and / or the plurality of powder mixtures, and / or the metal tungsten powder obtained in step 1 are sequentially layered and poured into a graphite mold to form a plurality of layers with gradient distribution of tungsten content, and pre-pressing is performed after each powder laying, and the next layer of powder laying is performed, and the pre-pressing pressure is 5-15 MPa;

[0012] Step 3: the mold containing the powder with gradient components is placed in the SPS furnace cavity, vacuumized to below 5 Pa for sintering preparation, and the preparation process is as follows:

[0013] axial pressure: 20-50 MPa,

[0014] heating rate: 20-80℃ / min,

[0015] sintering temperature: 1500-1800℃,

[0016] holding time: 20-60 min,

[0017] cooling rate: the cooling rate from the sintering temperature to 1000℃ is 3-15℃ / min, and the cooling from 1000℃ to room temperature is furnace cooling;

[0018] Step 4: the gradient material obtained after sintering is demolded, cooled and machined to obtain a gradient tungsten alloy material.

[0019] Preferably, the tungsten content in the plurality of tungsten alloy powders or the plurality of powder mixtures in step 1 is 85wt%-99wt% relative to the total weight of the tungsten alloy powder or the powder mixture.

[0020] Preferably, the plurality of tungsten alloy powders or the plurality of powder mixtures in step 1 is composed of rhenium in an amount greater than 0 and less than or equal to 15 wt%, zirconium oxide in an amount of 0 wt% to 3 wt%, and the balance tungsten.

[0021] Preferably, the blending in step 1 is performed by planetary ball milling or V-type mixing.

[0022] Preferably, the process conditions in step 3 are as follows:

[0023] Axial pressure: 20-40 MPa,

[0024] Heating rate: 40-55 ℃ / min,

[0025] Sintering temperature: 1750-1800 ℃,

[0026] Soaking time: 20-40 min,

[0027] Cooling rate: 15 ℃ / min from the sintering temperature to 1000 ℃, and furnace cooling from 1000 ℃ to room temperature.

[0028] The above preferred process is based on a large number of experimental tests and is obtained by trial and error. Under the above conditions, the prepared gradient material has better comprehensive performance.

[0029] Preferably, the interface joint shear strength of the gradient material is preferably greater than 200 MPa.

[0030] According to a second aspect of the present application, there is provided a gradient tungsten alloy product prepared from a gradient tungsten alloy material prepared by the SPS method for preparing a gradient tungsten alloy material according to the present application.

[0031] Preferably, the gradient tungsten alloy product is an anode target disc or a friction stir welding stir pin.

[0032] According to a third aspect of the present application, there is provided a friction stir welding stir pin, comprising a clamping portion, a stir pin shoulder and a stir pin tip portion, both ends of the stir pin shoulder being connected to the clamping portion and the stir pin tip portion, respectively, the clamping portion, the stir pin shoulder and the stir pin tip portion all being prepared from a tungsten-rhenium alloy, wherein the tungsten content in the tungsten-rhenium alloy of the clamping portion, the stir pin shoulder and the stir pin tip portion decreases in turn.

[0033] Preferably, the clamping portion is composed of 1 wt% to 3 wt% rhenium and 97 wt% to 99 wt% tungsten; more preferably, the clamping portion is composed of 3 wt% rhenium and 97 wt% tungsten.

[0034] Preferably, the pin shoulder of the friction stir welding tool is composed of rhenium in an amount greater than 3wt% and less than 9wt%, and tungsten in an amount greater than 91wt% and less than 97wt%; more preferably, the pin shoulder of the friction stir welding tool is composed of 5wt% rhenium and 95wt% tungsten.

[0035] Preferably, the pin tip of the friction stir welding tool is composed of 7wt%~13wt% rhenium, 1wt%~3wt% zirconium oxide, and the balance tungsten; more preferably, the pin tip of the friction stir welding tool is composed of 10wt% rhenium, 2wt% ZrO2, and 88wt% tungsten.

[0036] Preferably, the friction stir welding tool is integrally formed by SPS sintering.

[0037] Preferably, the interface joint of the friction stir welding tool has a shear strength of 200MPa or more.

[0038] According to a fourth aspect of the present application, a preparation method for preparing a friction stir welding tool is provided, comprising the following steps:

[0039] 1) preparing powders: respectively preparing a first powder composed of 7wt%~13wt% rhenium, 1wt%~3wt% zirconium oxide, and the balance tungsten; a second powder composed of rhenium in an amount greater than 3wt% and less than 9wt%, and tungsten in an amount greater than 91wt% and less than 97wt%, and a third powder composed of rhenium in an amount of 1wt%~3wt% and tungsten in an amount of 97wt%~99wt%, when preparing each powder, first add raw materials and stir uniformly, then put into a hard alloy ball mill jar, add hard alloy balls, the ball-to-material ratio is 5:1, vacuumize the hard alloy jar filled with materials, and place it in a planetary ball mill for ball milling and mixing;

[0040] 2) after ball milling, perform vacuum drying of the powders;

[0041] 3) sequentially layer the first powder, the second powder, and the third powder obtained by drying in step 2) in a graphite mold, and perform pre-pressing after completing each layer of powder laying, and then perform powder laying of the next layer, the pre-pressing pressure is 5~15MPa;

[0042] 4) place the mold in an SPS furnace cavity, vacuumize to below 5Pa for sintering preparation, and the preparation process is as follows:

[0043] axial pressure: 20~50MPa,

[0044] heating rate: 20~80℃ / min,

[0045] sintering temperature: 1500~1800℃,

[0046] holding time: 20~60min,

[0047] Cooling rate: the cooling rate from the sintering temperature to 1000℃ is 3~15℃ / min, and the cooling from 1000℃ to room temperature is furnace cooling;

[0048] 5) demolding the gradient material obtained after sintering, cooling, and then mechanical processing.

[0049] According to the fifth aspect of the present application, there is provided an anode target disc having a surface layer and a base layer, wherein the base layer is metallic tungsten and the surface layer is tungsten-rhenium alloy, and the content of rhenium in the tungsten-rhenium alloy is 3wt%~10wt%.

[0050] Preferably, the thickness of the surface layer is 0.7~1.5mm.

[0051] Advantages

[0052] 1. Designing the gradient composition of the material can solve the problem that the performance of single-component material cannot meet the actual application requirements, and improve the service life of the material.

[0053] 2. The change of the gradient composition of the material can effectively reduce the waste of the material, especially the protection of the resources of rare metals such as tungsten and rhenium, and can reduce the use cost of tungsten-rhenium material.

[0054] 3. The use of spark plasma sintering technology (SPS) can quickly and effectively prepare the gradient material, and the production process can be simplified, the sintering time is short, the energy consumption is low, the requirement for the vacuum degree of the equipment is low, and the production and preparation of the gradient material are effectively improved.

[0055] 4. The present application changes the composition gradient of the pure tungsten target, uses tungsten-rhenium alloy as the surface, and can effectively solve the brittleness of the tungsten material surface processing and improve the electron beam bombardment resistance of the target surface, improve the service life, and the shear strength of the interface between the tungsten-rhenium alloy and tungsten can reach more than 200MPa.

[0056] 5. The present application changes the composition gradient of the pure tungsten-rhenium stir head, and according to the different performance requirements of different components of the alloy, the hardness and wear resistance of the component sintered from the mixed powder of 1wt%~3wt% zirconium oxide, 7wt%~13wt% rhenium and the balance of tungsten are higher, which is used as the head region participating in the friction stir welding, W5Re-W3Re is used as the shaft part connected with the equipment, which effectively improves the service life of the stir head material and reduces the material cost, and the room temperature shear strength of the two joints can reach more than 200MPa, and the hardness of W10Re2ZrO2 can reach 450HV. 0.5 The above. BRIEF DESCRIPTION OF DRAWINGS

[0057] Figure 1 A schematic view showing an anode target disk prepared according to Example 1 of the present application.

[0058] Figure 2 A schematic view showing a friction stir welding tool prepared according to Example 3 of the present application. DETAILED DESCRIPTION

[0059] The present application will be described in detail below with reference to examples and drawings. The following examples are implemented on the premise of the technical solutions of the present application, and detailed implementation modes and specific operation processes are given, but the protection scope of the present application is not limited to the following examples.

[0060] The discharge plasma sintering furnace used in the following examples is a LABOX-6020 discharge plasma sintering system produced by Japan Sinter Land inc. The current type is direct current pulse current, and the pulse sequence is 40:7. The shear strength test uses an in-situ tension and compression mechanical testing system, and the shear rate is adjusted to 0.5 mm·min -1 .

[0061] The W powder used in the following examples has a D50 of less than 3 μm and is purchased from Xi'an Feilian New Material Co., Ltd.

[0062] The rhenium powder used has a D50 of less than 3 μm and is purchased from Xi'an Feilian New Material Co., Ltd.

[0063] The ZrO2 powder used has a D50 of less than 4 μm and is purchased from Zhuzhou Runfeng New Material.

[0064] The shear strength measuring device is an in-situ tension and compression mechanical testing system.

[0065] Example 1

[0066] Preparation of an anode target disk

[0067] Step 1: Pour the tungsten powder into a hard alloy jar, then take 100 g of rhenium powder and add it to 900 g of tungsten powder, put in hard alloy grinding balls, the ball-to-material ratio is 5:1, then vacuumize the hard alloy jar and place it in a planetary ball mill for ball milling and mixing, after completion, take it out and place it in a vacuum drying oven, vacuumize and heat to 100°C for powder drying. The tungsten powder is also placed in the drying oven for drying treatment.

[0068] Step 2: Pour the dried W10Re powder into a graphite mold first, then use a hydraulic press to pre-press the powder to 10 MPa, then add tungsten powder and continue to pre-press to 10 MPa, wherein the pressing head has a circular truncated cone cavity.

[0069] Step 3: Put the graphite mold containing W10Re-W double-layer powder into the SPS furnace cavity, vacuumize below 5 Pa, and the preparation process is as follows:

[0070] Axial pressure: 30 MPa,

[0071] Rising rate: 50℃ / min,

[0072] Target temperature: 1700℃,

[0073] Soaking time: 30 min,

[0074] Cooling rate: 10℃ / min from the target temperature to 1000℃, and then furnace cooling from 1000℃ to room temperature, and then machining.

[0075] The thickness of the tungsten-rhenium layer is 1.2±0.5 mm.

[0076] As shown in Figure 1 , the two parts of the anode target disc obtained after machining are as follows: the thin layer part in the upper layer is a W10Re alloy target surface, which is bombarded by an electron beam to generate X-rays, and the thickness is 1.2±0.5 mm. The thick layer part below is a W base, and the thickness ranges from 16±0.5 mm.

[0077] The interface joint room temperature shear strength of the W10Re-W gradient material prepared in this embodiment is 202 MPa, the W10Re alloy hardness is 350HV 0.5 , and the W hardness is 315HV 0.5 .

[0078] Embodiment 2

[0079] Preparation of anode target disc

[0080] Step 1: Pour tungsten powder into a hard alloy jar, then add 100g of rhenium powder to 900g of tungsten powder, put hard alloy grinding balls, the ball-to-material ratio is 5:1, then vacuumize the hard alloy jar, and place it in a planetary ball mill for ball milling and mixing. After completion, take it out and place it in a vacuum drying oven, vacuumize, and heat to 100℃ for powder drying. The corresponding tungsten powder is also placed in the drying oven for drying treatment.

[0081] Step 2: Pour the dried W10Re powder into a graphite mold first, then use a hydraulic machine to pre-press the powder to 10 MPa, then add tungsten powder and continue to pre-press to 10 MPa.

[0082] Step 3: Put the graphite mold containing W10Re-W double-layer powder into the SPS furnace cavity, vacuumize below 5 Pa, and the preparation process is as follows:

[0083] Axial pressure: 30 MPa,

[0084] Ramp rate: 50℃ / min,

[0085] Target temperature: 1800℃,

[0086] Soaking time: 30min,

[0087] Cooling rate: 10℃ / min from target temperature to 1000℃, and furnace cooling from 1000℃ to room temperature.

[0088] The thickness of the tungsten-rhenium layer is 1.2±0.5mm.

[0089] The interface joint of the W10Re-W gradient material prepared in this embodiment has a room temperature shear strength of 235MPa, and the hardness of the W10Re alloy is 365HV 0.5 , and the hardness of W is 319HV 0.5 .

[0090] Example 3

[0091] Preparation of a friction stir welding tool

[0092] Step 1: Pour tungsten powder into a hard alloy jar, then add 100g of rhenium powder to 880g of tungsten powder, and then add 20g of ZrO2 powder to it, put in hard alloy grinding balls, the ball-to-material ratio is 5:1, then vacuumize the hard alloy jar, and place it in a planetary ball mill for ball milling and mixing, after completion, take it out and place it in a vacuum drying box, vacuumize it, and heat it to 100℃ for powder drying to obtain W10Re2ZrO2 powder. In the same way, W3Re powder with a rhenium content of 3wt% and W5Re powder with a rhenium content of 5wt% are prepared.

[0093] Step 2: Pour the dried W10Re2ZrO2 powder into a graphite mold first, then use a hydraulic press to pre-press the powder to 10MPa, then add W5Re powder and continue to pre-press to 10MPa, and finally add W3Re powder and pre-press to 10MPa.

[0094] Step 3: Put the graphite mold containing the W10Re2ZrO2-W5Re-W3Re three-layer powder into the SPS furnace cavity, vacuumize it to below 5Pa, and the preparation process is as follows:

[0095] Axial pressure: 30MPa,

[0096] Ramp rate: 40℃ / min,

[0097] Target temperature: 1650℃,

[0098] Soaking time: 30min,

[0099] Cooling rate: 10℃ / min from target temperature to 1000℃, furnace cooling from 1000℃ to room temperature, then mechanical processing to obtain a friction stir welding tool.

[0100] After machining, a friction stir welding tool is obtained as shown in Figure 2 . The upper part of the friction stir welding tool is a clamping part, mainly connected to the equipment end, not directly involved in the friction stirring of the welding material, and the wear resistance and strength requirements are relatively low, so tungsten-rhenium alloy (W3Re alloy) with low rhenium content is used. The middle part of the friction stir welding tool is the tool shoulder, which is the transition area of the tool material, involved in the surface friction of the welding material and the continuous stirring and pressing of the softened metal, requiring certain strength, toughness and wear resistance, and the composition is W5Re alloy. The lower part of the friction stir welding tool is the tool tip, which is directly involved in the internal friction stirring of the welding material, requiring high strength, high toughness and good wear resistance, etc., and the composition is W10Re2ZrO2 composite material.

[0101] In this embodiment, the W10Re2ZrO2-W5Re and W5Re-W3Re interface joint room temperature shear strength of the W10Re2ZrO2-W5Re-W3Re gradient material prepared is 205MPa and 212MPa respectively, the W10Re2ZrO2 alloy hardness is 496HV 0.5 , the W5Re alloy hardness is 332HV 0.5 , and the W3Re hardness is 323HV 0.5 .

[0102] Embodiment 4

[0103] Preparation of a friction stir welding tool

[0104] Step 1: Pour tungsten powder into a hard alloy jar, then add 100g of rhenium powder to 880g of tungsten powder, then add 20g of ZrO2 powder, put in hard alloy grinding balls, ball to material ratio is 5:1, then vacuumize the hard alloy jar, place it in a planetary ball mill, ball mill and mix, after completion, take out and place in a vacuum drying oven, vacuumize and heat to 100℃, powder drying. In the same way, W3Re powder with 3wt% rhenium content and W5Re powder with 5wt% rhenium content are prepared.

[0105] Step 2: Pour the dried W10Re2ZrO2 powder into a graphite mold first, then use a hydraulic machine to pre-press the powder to 10MPa, then add W5Re powder, continue to pre-press to 10MPa, and finally add W3Re powder, pre-press to 10MPa.

[0106] Step 3: The graphite mold containing W10Re2ZrO2-W5Re-W3Re three-layer powder was loaded into the SPS furnace cavity, vacuumized to below 5 Pa, and the preparation process was as follows:

[0107] Axial pressure: 30 MPa,

[0108] Rising rate: 40 ℃ / min,

[0109] Target temperature: 1800 ℃,

[0110] Soaking time: 30 min,

[0111] Cooling rate: 10 ℃ / min from the target temperature to 1000 ℃, and then furnace cooling from 1000 ℃ to room temperature, and then mechanical processing to obtain a friction stir welding stir head.

[0112] The W10Re2ZrO2-W5Re and W5Re-W3Re interface joint room temperature shear strength of the W10Re2ZrO2-W5Re-W3Re gradient material prepared in this embodiment was 228 MPa and 223 MPa, respectively, the W10Re2ZrO2 alloy hardness was 512 HV 0.5 , the W5Re alloy hardness was 338 HV 0.5 , and the W3Re hardness was 326 HV 0.5 .

Claims

1. A stirring head for friction stir welding, comprising: The device includes a clamping part, a stirring head shoulder, and a stirring head needle tip. The two ends of the stirring head shoulder are connected to the clamping part and the stirring head needle tip, respectively. The clamping part, the stirring head shoulder, and the stirring head needle tip are all made of tungsten-rhenium alloy. The tungsten content in the tungsten-rhenium alloy of the clamping part, the stirring head shoulder, and the stirring head needle tip decreases in that order. The clamping part is composed of 1wt~3wt% rhenium and 97wt%~99wt% tungsten.

2. The stirring head for friction stir welding according to claim 1, wherein, The clamping part is composed of 3wt% rhenium and 97wt% tungsten.

3. The stirring head for friction stir welding according to claim 1, wherein, The shoulder of the stirring head is composed of rhenium with a content greater than 3 wt% and less than 9 wt% and tungsten with a content greater than 91 wt% and less than 97 wt%.

4. The stirring head for friction stir welding according to claim 3, wherein, The shoulder of the stirring head is composed of 5 wt% rhenium and 95 wt% tungsten.

5. The stirring head for friction stir welding according to claim 1, wherein, The tip of the stirring head is composed of 7wt%~13wt% rhenium, 1wt%~3wt% zirconium oxide and the balance tungsten.

6. The stirring head for friction stir welding according to claim 5, wherein, The tip of the stirring head is composed of 10 wt% rhenium, 2 wt% ZrO2 and 88 wt% tungsten.

7. The stirring head for friction stir welding according to claim 1, wherein, The stirring head for friction stir welding is integrally formed by SPS sintering; and / or The shear strength of the interface joint of the stirring head used for friction stir welding is above 200 MPa.

8. A method for preparing a stirring head for friction stir welding, comprising the following steps: 1) Powder preparation: Prepare a first powder consisting of 7wt%~13wt% rhenium, 1wt%~3wt% zirconium oxide, and the balance tungsten; a second powder consisting of rhenium with a content greater than 3wt% and less than 9wt% and tungsten with a content greater than 91wt% and less than 97wt%; and a third powder consisting of rhenium with a content of 1wt%~3wt% and tungsten with a content of 97wt%~99wt%. When preparing each powder, first add the raw materials and stir evenly, then put them into a cemented carbide ball mill jar, add cemented carbide balls, and the ball-to-material ratio is 5:

1. Vacuum the cemented carbide jar containing the materials and place it in a planetary ball mill for ball milling and mixing. 2) After ball milling, perform vacuum drying of the powder; 3) The first powder, second powder and third powder obtained from drying in step 2) are sequentially layered into a graphite mold. After each layer of powder is laid, pre-pressing is performed before laying the next layer. The pre-pressing pressure is 5~15MPa. 4) Place the mold in the SPS furnace cavity, evacuate to below 5 Pa, and sinter to prepare the mold. The preparation process is as follows: Axial pressure: 20~50MPa Heating rate: 20~80℃ / min Sintering temperature: 1500~1800℃ Insulation time: 20~60 minutes Cooling rate: The cooling rate from sintering temperature to 1000℃ is 3~15℃ / min, and the cooling from 1000℃ to room temperature is furnace cooling. 5) Demold the gradient material obtained after sintering, cool it, and then perform machining.

9. The method for preparing a stirring head for friction stir welding according to claim 8, wherein, The first powder consists of 7 wt% to 13 wt% rhenium powder, 1 wt% to 3 wt% zirconium oxide powder, and the balance tungsten powder; and / or The second powder consists of 5 wt% rhenium powder and 95 wt% tungsten powder; and / or The third powder is composed of 3 wt% rhenium powder and 97 wt% tungsten powder; and / or The first, second, and third powders obtained from drying in step 2) are sequentially layered into a graphite mold. Pre-pressing is performed after each layer is laid before proceeding to the next layer. The pre-pressing pressure is 5-15 MPa; and / or The process conditions for step 4 are as follows: Axial pressure: 20~40MPa Heating rate: 40~55℃ / min Sintering temperature: 1750~1800℃ Keep warm for 20-40 minutes. Cooling rate: The cooling rate from sintering temperature to 1000℃ is 15℃ / min, and the cooling rate from 1000℃ to room temperature is furnace cooling.

10. A SPS method for preparing gradient tungsten alloy materials, comprising the following steps: Step 1: Prepare various tungsten alloy powders with different tungsten contents, and / or various powder mixtures of metallic tungsten powder with other metal powders and optional metal oxide powders, mix them evenly and then dry them; Step 2: The various tungsten alloy powders with different tungsten contents obtained in Step 1, and / or mixtures of various powders, and / or metallic tungsten powder are sequentially poured into a graphite mold to form multiple layers with a gradient distribution of tungsten content. After each layer of powder is laid, pre-pressing is performed before laying the next layer. The pre-pressing pressure is 5~15MPa. Step 3: Place the mold containing the gradient composition powder into the SPS furnace chamber, and sinter it under vacuum to below 5 Pa. The preparation process is as follows: Axial pressure: 20~50MPa Heating rate: 20~80℃ / min Sintering temperature: 1500~1800℃ Insulation time: 20~60 minutes Cooling rate: The cooling rate from sintering temperature to 1000℃ is 3~15℃ / min, and the cooling from 1000℃ to room temperature is furnace cooling. Step 4: Demold the sintered gradient material, cool it, and machine it to obtain the gradient tungsten alloy material.

11. The SPS method for preparing gradient tungsten alloy materials according to claim 10, wherein, The tungsten content in the various tungsten alloy powders or powder mixtures in step 1 is 85 wt% to 99 wt% relative to the total weight of the tungsten alloy powders or powder mixtures; and / or The multiple tungsten alloy powders or mixtures of multiple powders mentioned in step 1 consist of rhenium with a content greater than 0 and less than 15 wt%, zirconium oxide with a content of 0 wt% to 3 wt%, and the balance tungsten; and / or The mixing in step 1 is carried out by planetary ball milling or V-type mixing; and / or The process conditions for step 3 are as follows: Axial pressure: 20~40MPa Heating rate: 40~55℃ / min Sintering temperature: 1750~1800℃ Keep warm for 20-40 minutes. Cooling rate: The cooling rate from sintering temperature to 1000℃ is 15℃ / min, and the cooling rate from 1000℃ to room temperature is furnace cooling.

12. The SPS method for preparing gradient tungsten alloy materials according to claim 10, wherein, The shear strength of the gradient material interface joint is above 200 MPa.

Images