Rotary anode target disc with WRe fiber structure and preparation method of rotary anode target disc

Abstract

The invention discloses a rotating anode target disc with a WRe fiber structure and a preparation method of the rotating anode target disc. The rotating anode target disc comprises a tungsten-rhenium alloy layer and a TZM alloy layer which are sequentially arranged from top to bottom, and the tungsten-rhenium alloy layer and the TZM alloy layer are of a layered structure and combined into a whole. Through the structural design that the high-density tungsten-rhenium wire is perpendicular to the annular groove, the capacity of the rotating anode target disc for dealing with thermal expansion in the cold and hot alternating environment is improved, the tungsten-rhenium wire can expand towards a gap after being heated and can retract after being cooled, and tungsten-rhenium layer chap caused by thermal stress is effectively reduced; the strength of the tungsten-rhenium wire is improved, and the chapping possibility of the tungsten-rhenium layer is reduced. The structural stability of the rotating anode target disc in a complex operation environment is improved, and it is guaranteed that the rotating anode target disc can keep an excellent working state for a long time.

Description

Technical Field

[0001] This invention relates to the field of target disk preparation, and specifically to a rotating anode target disk with a WRe fiber structure and its preparation method. Background Technology

[0002] CT (Computed Tomography) is a non-invasive, high-resolution imaging technique that clearly displays lesions inside the human body. It has become an indispensable tool in modern medical diagnosis and healthcare. The CT tube is the X-ray source in the CT scanner, considered the "core" of the machine, while the rotating anode target, as the source of X-rays from the CT tube, is its "heart."

[0003] Patent CN118699370A provides a method for forging a rotating anode target and the resulting rotating anode target, comprising the following steps: pressing titanium-zirconium-molybdenum alloy powder and tungsten-rhenium alloy powder to obtain a preform; sintering the preform under a protective atmosphere to obtain a sintered target; and sequentially forging and annealing the sintered target to obtain a rotating anode target. The tungsten-rhenium / TZM rotating anode target obtained by this method has a modified tungsten-rhenium alloy microstructure on the target surface, which effectively prevents the generation and propagation of cracks during product use, further improving product lifespan and yielding a high product quality. The rotating anode target possesses excellent properties such as fine grains, uniform microstructure, high density, low impurity element content, and high interfacial bonding strength. It also exhibits high surface hardness, uniform element diffusion at the interface, good heat dissipation, good thermal shock resistance, and large product size.

[0004] Patent CN118553580A relates to a lightweight rotating anode target for X-ray tubes. The target includes a two-layer structure: a substrate and a rhenium-tungsten alloy layer covering the surface of the substrate. The substrate is a graphite layer. A central hole matching the tube spindle is provided in the middle of the target. The graphite layer is connected to the tube spindle via a fixing structure. The rhenium-tungsten alloy layer is deposited on the graphite layer by magnetron sputtering or coating. This invention's anode target includes a two-layer structure of a rhenium-tungsten alloy layer and a graphite layer, eliminating the intermediate TZM alloy layer, significantly reducing the cost of the anode target, and also reducing its weight. Under high-speed rotation conditions, the lightweight target reduces the load on the bearings and improves the target's service life.

[0005] During operation, the tungsten-rhenium layer of a rotating anode target experiences a rapid temperature change from room temperature to 2600°C due to electron beam bombardment. This thermal shock gradually causes cracks on the surface of the tungsten-rhenium layer, affecting its service life. Better thermal conductivity results in less cracking and a longer service life. Existing tungsten-rhenium layers are equiaxed crystals with numerous grain boundaries, leading to insufficient thermal conductivity. Therefore, this invention provides a method for fabricating a rotating anode target disk with a WRe fiber structure. Summary of the Invention

[0006] The purpose of this invention is to provide a rotating anode target disk with a WRe fiber structure and its preparation method. Through the structural design of a high-density tungsten-rhenium wire with vertical annular grooves, the rotating anode target disk's ability to cope with thermal expansion under alternating hot and cold environments is improved. This allows the tungsten-rhenium wire to expand into the gaps when heated and contract when cooled, effectively reducing tungsten-rhenium layer cracking caused by thermal stress; it also increases the strength of the tungsten-rhenium wire and reduces the possibility of tungsten-rhenium layer cracking. Furthermore, it improves the structural stability of the rotating anode target disk in complex operating environments, ensuring that it can maintain excellent working condition over a long period.

[0007] The present invention provides a rotating anode target disk with a WRe fiber structure, comprising a tungsten-rhenium alloy layer 1 and a TZM alloy layer 2 arranged sequentially from top to bottom, and the two are integrated in a layered structure; the tungsten-rhenium alloy layer 1 contains a WRe fiber reinforcement 101.

[0008] Furthermore, the target disk includes a tungsten-rhenium alloy layer 1, a TZM alloy layer 2, and a graphite layer arranged sequentially from top to bottom, and the three layers are combined into one unit in a layered structure.

[0009] Furthermore, the tungsten-rhenium alloy layer 1 is a composite structure, consisting of a high-temperature brazing layer 102 and a WRe fiber reinforcement 101; the WRe fiber reinforcement 101 consists of multiple short-cut tungsten-rhenium wires, one end of which is metallurgically bonded to the TZM alloy layer 2 through the high-temperature brazing layer 102, while the other end is exposed to jointly form the electron bombardment working surface of the rotating anode target disk.

[0010] Furthermore, the bonding surface between the TZM alloy layer 2 and the WRe fiber reinforcement 101 is a sloping groove structure, forming an annular groove, and the WRe fiber reinforcement 101 is vertically disposed in the annular groove.

[0011] Furthermore, the depth of the annular groove is 0.5-5mm and the width is 5-25mm.

[0012] Furthermore, the short-cut tungsten rhenium wires are closely arranged within the annular groove.

[0013] Furthermore, the short-cut tungsten rhenium wire in the WRe fiber reinforcement 101 has a rhenium weight percentage content of 3%-25%, a diameter of 0.05-1.5 mm, and a density of ≥99.9%.

[0014] Preferably, the rhenium content by weight is 3%, 5%, 10%, 15%, 20%, or 25%, more preferably 10%-20%. The diameter of the tungsten rhenium wire is 0.05 mm, 0.1 mm, 0.2 mm, 0.5 mm, 0.8 mm, 1 mm, or 1.5 mm, more preferably 0.1-1 mm. The short-cut tungsten rhenium wire used in this invention has a density of over 99.9%. High density means fewer internal defects, higher strength, and better creep resistance. During thermal cycling, high-strength fibers are less prone to plastic deformation and crack initiation. Therefore, the increased strength due to high density, in conjunction with the aforementioned stress release mechanism, reduces cracking in the tungsten rhenium layer.

[0015] Furthermore, the high-temperature brazing layer 102 comprises, by weight, 1-5 parts W, 1-10 parts Mo, 1-5 parts Ta, and 80-97 parts Nb.

[0016] Preferably, the weight parts of W are 1, 2, 3, 4 or 5; the weight parts of Mo are 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10; the weight parts of Ta are 1, 2, 3, 4 or 5; and the weight parts of Nb are 80, 82, 84, 86, 88, 90, 92, 94, 96 or 97.

[0017] On the other hand, the present invention also provides a method for preparing a rotating anode target disk with a WRe fiber structure, the steps of which include: (1) Make an annular groove on the inclined surface of the TZM layer and place solder powder at the bottom of the groove; (2) Place the tungsten rhenium wire vertically to the bottom of the annular groove, and then place the structure obtained above in a high-temperature environment to melt the solder. This will combine the tungsten rhenium wire and the TZM disk to obtain the rotating anode target disk with the WRe fiber structure.

[0018] In the preparation method of this invention, there are certain spaces between the tungsten-rhenium wires. When heated, the tungsten-rhenium wires can expand into the gaps and shrink back when cooled, which can effectively reduce and eliminate the generation of cracks in the tungsten-rhenium layer. At the same time, the tungsten-rhenium wires have a high density, and the increased strength brought about by the high density can also reduce cracks in the tungsten-rhenium layer.

[0019] Furthermore, the preparation method further includes: (a) laying TZM powder in a mold, and obtaining a TZM layer by pressing, sintering and forging.

[0020] Furthermore, in step (a), the pressing pressure is ≥100MPa and the pressing time is ≥1min.

[0021] Furthermore, in step (a), the sintering temperature is ≥2000℃ and the sintering time is ≥3h.

[0022] Furthermore, in step (a), the forging temperature is ≥1500℃ and the forging pressure is ≥100MPa.

[0023] Furthermore, the solder is all in powder form, with a purity ≥99.5% and a particle size ≤50μm. Preferably, the particle size is 10μm, 20μm, 30μm, 40μm, or 50μm.

[0024] Furthermore, the solder comprises the following raw materials in parts by weight: W 1-5 parts, Mo 1-10 parts, Ta 1-5 parts, and Nb 80-97 parts.

[0025] Preferably, the weight parts of W are 1, 2, 3, 4 or 5; the weight parts of Mo are 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10; the weight parts of Ta are 1, 2, 3, 4 or 5; and the weight parts of Nb are 80, 82, 84, 86, 88, 90, 92, 94, 96 or 97.

[0026] Furthermore, the high-temperature environment for melting the solder is 2500-2600℃, the holding time is 0.5-1.5h, and the pressure is ≤0.01Pa.

[0027] Furthermore, in step (2), the length of the tungsten rhenium wire is 0.1-3 mm longer than the groove depth, preferably 0.5-1 mm longer.

[0028] Furthermore, the preparation method also includes: (3) machining the composite target disk to remove excess tungsten rhenium wire.

[0029] This invention achieves metallurgical bonding in an ultra-high vacuum environment using a high-temperature brazing filler with specific components, ensuring extremely high bonding strength between the WRe fiber reinforcement and the TZM substrate. This avoids the risk of interfacial delamination under thermal stress and allows the stress release mechanism to function stably and effectively over a long period.

[0030] The beneficial effects of this invention are as follows: This invention innovatively designs the traditional dense tungsten-rhenium layer as a fiber reinforcement composed of discrete, high-density short-cut tungsten-rhenium wires. These vertically arranged tungsten-rhenium wires naturally contain gaps or grooves. When the target disk's working surface is rapidly heated by electron beam bombardment, each tungsten-rhenium wire can independently expand radially. This expansion space is accommodated by the gaps between adjacent fibers, thus greatly absorbing thermal expansion deformation and preventing the accumulation of enormous compressive stress in the overall tungsten-rhenium layer due to the constraint of the TZM (Tungsten-Zero-Metal) substrate. During cooling, the fibers can freely shrink. This unique structure effectively reduces and eliminates, at the physical level, the fundamental driving force of thermal stress that leads to cracking in the tungsten-rhenium layer. Attached Figure Description

[0031] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of the conventional structure of a rotating anode target; Figure 2 This is a schematic diagram of the preparation process of the present invention.

[0033] Figure 3 This is a cross-sectional view of the rotating anode target of the present invention. In the figure, 1- Tungsten-rhenium alloy layer; 101- WRe fiber reinforcement (short-cut tungsten-rhenium wire); 102- High-temperature brazing layer; 2- TZM alloy layer; 201- TZM base layer / annular groove. Detailed Implementation

[0034] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Example 1: Preparation of the rotating anode target disk of the present invention The TZM layer was grooved at an angle to obtain an annular groove with a depth of 0.5 mm and a width of 5 mm. Solder powder with the composition of W (5), Mo (10), Ta (5), Nb (80) and a particle size of 10 μm was placed at the bottom of the groove. Tungsten rhenium wire (containing 20Re, diameter 0.1 mm, length 1 mm, density ≥99.9%) was placed perpendicular to the bottom of the annular groove. The placed TZM disk was kept at 2600℃ for 1 h under vacuum (≤0.01 Pa) to melt the solder and combine the tungsten rhenium wire and the TZM disk. The combined TZM disk was machined to remove excess tungsten rhenium wire.

[0036] Performance testing: After 20,000 cycles under operating conditions of 70kW / 15s, the average width of the cracks is 1μm, which can effectively reduce the cracking of the tungsten-rhenium layer.

[0037] Example 2: Preparation of the rotating anode target disk of the present invention The TZM layer was grooved at an angle to obtain an annular groove with a depth of 5 mm and a width of 25 mm. Solder powder with the composition of W (1), Mo (1), Ta (1), and Nb (97) and a particle size of 50 μm was placed at the bottom of the groove. Tungsten rhenium wire (containing 20 Re, with a diameter of 1 mm, a length of 6 mm, and a density of ≥99.9%) was placed perpendicular to the bottom of the annular groove. The placed TZM disk was kept at 2500℃ for 1 h under vacuum (≤0.01 Pa) to melt the solder and combine the tungsten rhenium wire and the TZM disk. The combined TZM disk was machined to remove excess tungsten rhenium wire.

[0038] Performance testing: After 20,000 cycles under operating conditions of 70kW / 15s, the average width of the cracks is 2μm, which can effectively reduce the cracking of the tungsten-rhenium layer.

[0039] Example 3: Preparation of the rotating anode target disk of the present invention The TZM layer was grooved at an angle to obtain an annular groove with a depth of 3 mm and a width of 15 mm. Solder powder with the composition of W (2), Mo (5), Ta (3), Nb (90) and a particle size of 30 μm was placed at the bottom of the groove. Tungsten rhenium wire (containing 10Re, diameter 0.5 mm, length 4 mm, density ≥99.9%) was placed perpendicular to the bottom of the annular groove. The placed TZM disk was kept at 2550℃ for 1 h under vacuum (≤0.01 Pa) to melt the solder and combine the tungsten rhenium wire and the TZM disk. The combined TZM disk was machined to remove excess tungsten rhenium wire.

[0040] Performance testing: After 20,000 cycles under the working conditions of 70kW / 15s, the average width of the crack is 1.5μm, which can effectively reduce the cracking of the tungsten-rhenium layer.

[0041] Comparative Example 1: The same method as in Example 1 was used, except that the solder composition was W (6), Mo (9), Ta (5), Nb (80), and the powder particle size was 10 μm.

[0042] Comparative Example 2: The same method as in Example 1 was used, except that the solder composition was W (0), Mo (1), Ta (1), Nb (98), and the powder particle size was 50 μm.

[0043] Comparative Example 3: The same method as in Example 1 was used, except that the solder composition was W (6), Mo (9), Ta (5), Nb (80), the powder particle size was 60 μm, and the holding temperature was 2550℃.

[0044] Comparative Example 4: Preparation of target disks using mature technology (1) Preparation of tungsten-rhenium alloy powder (containing 20Re) and TZM powder: The alloy powder was mixed in a solid-solid manner using a planetary ball mill for 24 hours; (2) The two powders are pressed into shape in the mold: TZM powder is placed in the mold first, then tungsten alloy powder is laid on top, and then pressed. The pressure is 300MPa and the holding time is 10min. After demolding, the composite powder blank is obtained. (3) High-temperature sintering of composite compact: The pressed composite compact is sintered at a high temperature of 2500℃ for 6 hours to obtain a composite sintered compact. (4) Forging of composite sintered billet: The sintered composite billet is forged at a high temperature of 1600℃ and a forging pressure of 300MPa. (5) Machining: The forged composite billet is machined to obtain the final dimensions, wherein the thickness of the tungsten-rhenium layer is .

[0045] Performance testing: After 20,000 cycles under operating conditions of 70 kW / 15 s, the average width of the tungsten-rhenium layer cracks was 3 μm.

[0046] The metal-mixed solders used in the examples and comparative examples are shown in Table 1 below.

[0047] Principles and steps not explicitly described in this invention are all obtainable by those skilled in the art through conventional technical means, and therefore will not be elaborated upon. Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A rotating anode target disk with a WRe fiber structure, characterized in that, It includes a tungsten-rhenium alloy layer (1) and a TZM alloy layer (2) arranged sequentially from top to bottom, and the two are combined into one in a layered structure; the tungsten-rhenium alloy layer (1) contains WRe fiber reinforcement (101).

2. The rotating anode target disk with a WRe fiber structure according to claim 1, characterized in that, The tungsten-rhenium alloy layer (1) is a composite structure, consisting of a high-temperature brazing layer (102) and a WRe fiber reinforcement (101). The WRe fiber reinforcement (101) consists of multiple short-cut tungsten-rhenium wires. One end of the short-cut tungsten-rhenium wires is metallurgically bonded to the TZM alloy layer (2) through the high-temperature brazing layer (102), while the other end is exposed to jointly form the electron bombardment working surface of the rotating anode target disk.

3. The rotating anode target disk with a WRe fiber structure according to claim 2, characterized in that, The bonding surface between the TZM alloy layer (2) and the WRe fiber reinforcement (101) is a sloping groove structure, forming an annular groove, and the WRe fiber reinforcement (101) is vertically arranged in the annular groove.

4. The rotating anode target disk with a WRe fiber structure according to claim 3, characterized in that, The depth of the annular groove is 0.5-5mm and the width is 5-25mm.

5. The rotating anode target disk with a WRe fiber structure according to claim 1, characterized in that, The short-cut tungsten rhenium wire in the WRe fiber reinforcement (101) has a rhenium weight percentage content of 3%-20%, a diameter of 0.1-1 mm, and a density of ≥99.9%.

6. The rotating anode target disk with a WRe fiber structure according to claim 2, characterized in that, The high-temperature brazing layer (102) comprises, by weight, 1-5 parts W, 1-10 parts Mo, 1-5 parts Ta, and 80-97 parts Nb.

7. A method for preparing a rotating anode target disk with a WRe fiber structure as described in any one of claims 1-6, characterized in that the step... include: (1) Make an annular groove on the TZM layer with an inclined surface and place solder powder at the bottom of the groove; (2) Place the tungsten rhenium wire vertically to the bottom of the annular groove, and then place the structure obtained above in a high-temperature environment to melt the solder. This will combine the tungsten rhenium wire and the TZM disk to obtain the rotating anode target disk with the WRe fiber structure.

8. The method for preparing a rotating anode target disk with a WRe fiber structure according to claim 7, characterized in that, The solders are all powders with a purity of ≥99.5% and a particle size of ≤50μm. The composition of the solder powder by weight includes: W 1-5 parts, Mo 1-10 parts, Ta 1-5 parts, and Nb 80-97 parts.

9. The method for preparing a rotating anode target disk with a WRe fiber structure according to claim 7, characterized in that, The high-temperature environment for melting the solder is 2500-2600℃, the holding time is 0.5-1.5h, and the pressure is ≤0.01Pa.

10. The method for preparing a rotating anode target disk with a WRe fiber structure according to claim 7, characterized in that, In step (2), the length of the tungsten rhenium wire is 0.1-3 mm longer than the groove depth; the preparation method also includes: (3) machining the composite target disk to remove excess tungsten rhenium wire.

Images