An anode target disk structure

Abstract

This invention discloses an anode target disk structure, comprising a disk surface layer, a disk body, and a substrate layer; the disk surface layer is fixedly connected above the disk body; the disk body is fixedly connected above the substrate layer; the disk surface layer includes an end face and an annular side face disposed on the outer side of the end face; an outer ring edge is formed between the end face and the annular side face; the end face has an annular bombardment area that bears electron beam bombardment and generates X-rays; residual compressive stress impact craters formed after laser shock strengthening are distributed on the anode target disk; the residual compressive stress impact craters are composed of the annular side face of the disk surface layer and the area between the outer edge of the annular bombardment area and the outer ring edge in the end face of the disk surface layer. The beneficial effects of this invention are: by adopting the residual compressive stress impact crater structure design in the above technical solution, a more advantageous strengthening impact effect can be obtained, the impact strength can be improved, and a cost advantage can be achieved.

Description

Technical Field

[0001] This invention relates to a target disk structure, specifically an anode target disk structure. Background Technology

[0002] The anode target is the core component of the X-ray tube, directly bearing the bombardment of the electron beam. Therefore, the high-temperature fatigue resistance of the anode target directly determines the service life of the X-ray tube. Laser shock peening, as an emerging surface treatment process, utilizes a high-energy laser beam to load the metal surface. The mechanical effect of the shock wave generated by the induced plasma explosion induces compressive stress perpendicular to the material surface. This residual compressive stress reduces the tensile stress level under alternating loads, lowering the average stress level and effectively inhibiting crack initiation and propagation, thereby effectively improving the strength, hardness, wear resistance, and stress corrosion resistance of metal components. Currently, the academic community has attempted to apply laser shock peening to anode targets to improve their fatigue resistance. However, current anode target structures do not offer significant strengthening performance advantages after laser shock peening, failing to achieve the desired strengthening effect and the most economical cost control. Summary of the Invention

[0003] To address the problems existing in the prior art, the present invention provides an anode target disk structure, thereby solving the aforementioned technical problems.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is: an anode target disk structure, comprising a disk surface layer, a disk body, and a substrate layer; the disk surface layer is fixedly connected above the disk body; the disk body is fixedly connected above the substrate layer;

[0005] The disk surface layer includes an end face and an annular side face disposed on the outer side of the end face; the end face and the annular side face form an outer ring edge; the end face has an annular bombardment area that bears electron beam bombardment and generates X-rays;

[0006] The anode target disk is provided with residual compressive stress impact craters formed after laser shock enhancement; the residual compressive stress impact craters are composed of the annular side surface of the disk surface layer and the area between the outer edge of the annular bombardment zone and the outer ring edge in the end face of the disk surface layer; there is an inner ring edge at the middle position of the end face; and there is a bottom edge at the lowest position of the annular side surface.

[0007] Furthermore, a flexible medium is provided on the upper surface of the end face as an absorption layer.

[0008] Furthermore, the absorbent layer is aluminum foil or black adhesive.

[0009] Furthermore, a flexible constraint layer is provided on the edge of the outer ring.

[0010] Furthermore, the flexible constraint layer is water or an inorganic salt melt.

[0011] Furthermore, the flexible constraint layer is a saturated inorganic salt melt.

[0012] Furthermore, the anode target disk is a tungsten target.

[0013] The beneficial effects of the present invention are: by adopting the residual compressive stress impact crater structure design in the above technical solution, a more advantageous enhanced impact effect can be obtained, the impact strength can be improved, and a cost advantage can be achieved. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the anode target disk in an embodiment of the present invention;

[0015] Figure 2 This is a partial unfolded view of the anode target disk in an embodiment of the present invention;

[0016] Figure 3 This is a bottom view of the disk surface layer in an embodiment of the present invention;

[0017] Figure 4 This is a path diagram of the path processing method on the disk surface layer in an embodiment of the present invention;

[0018] Figure 5 This is a distribution diagram of the first laser shock spot and the second laser shock spot in an embodiment of the present invention.

[0019] Among them, 10 is the disk surface layer; 11 is the end face; 12 is the annular side surface; 13 is the outer ring edge; 14 is the inner ring edge; 15 is the annular bombardment area; 16 is the bottom edge; 20 is the disk body; 30 is the substrate layer; 21 is the first path; 22 is the second path; 23 is the third path; 24 is the fourth path; 211 is the first laser shock spot; 221 is the second laser shock spot. Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. However, it should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of the invention.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention.

[0022] like Figure 1 , Figure 2 and Figure 3As shown, an anode target disk structure includes a disk surface layer 10, a disk body 20, and a substrate layer 30; the disk surface layer 10 is fixedly connected above the disk body 20; the disk body 20 is fixedly connected above the substrate layer 30.

[0023] The disk layer 10 includes an end face 11 and an annular side surface 12 disposed outside the end face 11; the end face 11 and the annular side surface 12 form an outer ring edge 13; the end face 11 has an annular bombardment area 15 that bears electron beam bombardment and generates X-rays;

[0024] The anode target disk is provided with residual compressive stress impact pits formed after laser shock strengthening; the residual compressive stress impact pits are composed of the annular side surface 12 of the disk layer 10 and the area between the outer edge of the annular bombardment zone 15 and the outer ring edge 13 in the end face 11 of the disk layer 10.

[0025] In this preferred embodiment, a flexible medium is provided on the upper surface of the end face 11 as an absorption layer.

[0026] In this embodiment, the absorbent layer is preferably aluminum foil or black adhesive.

[0027] In this preferred embodiment, the shape of the disk layer 10 is not the flat plate shape commonly analyzed. That is, the disk layer 10 not only has an end face 11, but also an annular side face 12, which intersect at the outer ring edge 13. Generally, the end face 11 and the annular side face 12 are perpendicular to each other. As one implementation of this technical solution, the end face 11 has an inner ring edge 14 at the middle position, and the annular side face 12 has a bottom edge 16 at the bottommost position.

[0028] When an electron beam bombards the anode target disk as a particle beam, it induces stress vibrations in the disk's surface layer. The electron beam first compresses the material at the impact point, creating a shock wave inside the anode target disk. The material rebounds at the impact point, and simultaneously, the shock wave propagates to the outer ring edge 13 of the anode target disk's surface layer 10, first compressing the material and then returning in the opposite direction, causing it to rebound. The cracks propagated by the rebound of material under high-temperature conditions are much smaller than those propagated by material rebound under low-temperature conditions, while the temperature of the inner ring edge 14 is much higher than that of the outer ring edge 13.

[0029] Therefore, in terms of the response to stress vibration, both the butterfly-shaped analysis model and the plate analysis model share the same characteristic: the outer ring edge 13, due to its convex shape, will compress and rebound under the action of the shock wave, making it a potential crack initiation point. In the plate analysis model, the shock wave will bounce off the outer ring edge 13, and the cracks initiating at this edge will propagate towards the center of the disk layer with the propagation of the reverse shock wave. This is why the industry has proposed extending the laser shock reinforcement area to both the outer ring edge 13 and the center of the disk layer 10.

[0030] However, the butterfly-shaped analysis model and the plate-shaped analysis model differ in their response to stress vibration. In the butterfly-shaped analysis model, the outer ring edge 13 is not the end of the entire disk layer material. The shock wave will not be reflected at the outer ring edge 13, but will continue to propagate along the initial propagation direction on the annular side 12 of the disk layer. Therefore, the cracks that originate from the outer ring edge 13 will first develop on the annular side 12 of the disk layer as the shock wave propagates, and then develop towards the center of the disk layer along the propagation of the reverse shock wave.

[0031] For the reasons mentioned above, the laser shock to the anode target disk surface layer proposed in this technical solution needs to cover the annular side 12 of the disk surface layer 10.

[0032] In this preferred embodiment, a flexible constraint layer is provided on the outer ring edge 13.

[0033] In this embodiment, the flexible constraint layer is preferably water or an inorganic salt melt.

[0034] In this preferred embodiment, the flexible constraint layer is a saturated inorganic salt melt.

[0035] The laser impact path that strikes the side of the disk layer 10 in a direction away from the center of the disk layer 10 is the first path 21; in step S33, the laser impact path that returns to the center of the disk layer 10 and strikes the side of the disk layer 10 point by point is the second path 22; in step S34, the laser impact path that strikes the area between the outer edge of the annular bombardment area 15 and the outer ring edge 13 of the end face 11 of the disk layer 10 in a direction pointing to the center of the disk layer 10 is the third path 23; the laser impact path that strikes the center of the inner ring edge 14 point by point is the fourth path 24; the fourth path 24 applies to the area between the inner edge of the annular bombardment area 15 and the inner ring edge 14.

[0036] On the first path 21, the positions of the various first laser impact spots 211 formed by the pulsed laser beam are spaced apart from each other;

[0037] On the second path 22, the positions of each second laser shock spot 221 formed by the pulsed laser beam are spaced apart from each other, and the position of each second laser shock spot 221 is located between two first laser shock spots 211 or each second laser shock spot overlaps with two adjacent first laser shock spots 211.

[0038] On the third path 23, the third laser shock spots formed by the pulsed laser beam are spaced apart from each other or overlapped with each other.

[0039] Working principle: The anode target disk to be strengthened is clamped onto the laser shock strengthening equipment. The disk surface layer 10 of the anode target disk is positioned relative to the laser head of the laser shock strengthening equipment. As a disk-type part, the anode target disk can be positioned on the impact worktable of the laser shock strengthening equipment by clamping with claws or V-blocks. The laser shock strengthening equipment can use a solid-state pulsed laser, a gas pulsed laser, or a fiber pulsed laser.

[0040] Subsequently, a pulsed laser beam is emitted through a laser shock intensification treatment device (the pulse energy of the laser beam is preferably 3.89J, 5.43J, 8J, etc.).

[0041] Finally, the pulsed laser beam impacts the target coverage area of ​​the anode target disk; wherein, the target coverage area consists of the annular side surface 12 of the disk layer 10 and the area between the outer edge of the annular bombardment zone 15 and the outer ring edge 13 in the end face 11 of the disk layer 10. That is, the pulsed laser beam only covers these two areas in the target coverage area of ​​the anode target disk to achieve stable strengthening; at the same time, laser shock strengthening still requires impacting the outer ring edge 13 of the disk layer 10 first, that is, the outer ring edge 13 is still the source point of crack initiation.

[0042] Specifically, the pulsed laser beam impacts the target coverage area of ​​the anode target disk in the following manner: first, the pulsed laser beam impacts the outer ring edge of the disk surface layer; then, it impacts the annular side surface of the disk surface layer point by point along a direction away from the center of the disk surface layer; next, it returns along a direction pointing towards the center of the disk surface layer and impacts the annular side surface of the disk surface layer point by point; finally, it impacts the area between the outer edge of the annular bombardment zone and the outer ring edge of the end face of the disk surface layer in a sequential manner along a direction pointing towards the center of the disk surface layer.

[0043] In this technical solution, the reason for excluding the annular bombardment zone 15 from the laser shock strengthening loading area due to the poor economic efficiency and high cost of anode target disk impact strengthening as mentioned above is explained in detail below:

[0044] It is known in academia that different metals have different sensitivities to high-temperature thermal release of residual compressive stress, but these sensitivities increase significantly after reaching a certain temperature. For example, some researchers have measured that the stress release rate of nickel-based alloys at 600 ℃, 700 ℃, and 800 ℃ gradually increases from 12.5% ​​to 77.7% and 82.1%, respectively.

[0045] To address this, the applicant conducted experiments on the residual stress release of the tungsten target at high temperatures of 2300°C and 1800°C (using a high-energy pulsed lamp-pumped YAG laser (Gaia-R series, THALES, France), with parameters of 5 mm spot diameter, 1064 nm wavelength, 10 nm pulse width, and 5.43 joule pulse energy). The experiments showed that at 2300°C, the residual stress release of the tungsten target exceeded 90%, while at 1800°C, the residual stress release was approximately 10%.

[0046] The temperature of 2300 degrees Celsius is the service temperature of the annular bombardment zone 15 of the anode target disk; the temperature of 1800 degrees Celsius is the service temperature of the outer ring edge 13 of the anode target disk (the anode target disk dissipates heat due to high-speed rotation during service). Therefore, considering the release behavior of residual stress on the tungsten target at high temperatures, there is no need to load shock waves onto the annular bombardment zone 15, while the outer ring edge 13 can still effectively load shock waves.

[0047] Therefore, this application proposes not to strengthen the annular bombardment zone 15 of the disk surface layer. On the one hand, the residual compressive stress obtained after processing the annular bombardment zone 15 will be significantly released with the increase of temperature; on the other hand, the annular bombardment zone 15 is not the source point of crack propagation, nor is it the core area for strengthening.

[0048] The applicant conducted experimental verification. Using a high-energy pulsed lamp-pumped YAG laser (Gaia-R series, THALES, France), with parameters of 5 mm spot diameter, 1064 nm wavelength, 10 nm pulse width, and 5.43 joule pulse energy, the pulsed laser beam was applied point-by-point to the annular side 12 of the disk layer and the area between the annular bombardment zone 15 and the outer ring edge 13 of the end face 11 of the disk layer 10, without applying the annular bombardment zone 15. Compared with the conventional method of comprehensively strengthening the end face 11, the fatigue life (effective number of working cycles of the anode target disk) of the anode target disk was increased by more than 15%. The experimental results are consistent with the theoretical qualitative analysis.

[0049] Based on the above scheme, the applicant further optimized the scheme. Given the understanding of the crack initiation and propagation patterns in the butterfly model, in order to further improve the strengthening effect of laser shock stabilization on the anode target disk, the loading path of laser shock stabilization should be consistent with the crack propagation pattern, thereby better suppressing cracks.

[0050] like Figure 4 As shown, in order to make the loading path of the pulsed laser beam match the crack propagation law, a three-path processing method is designed. That is, in one radial direction of the disk layer, the outer ring edge 13 of the disk layer is first impacted. Taking the outer ring edge 13 as the starting point, the annular side surface 12 of the disk layer is loaded along the direction away from the center of the disk layer 10 using the first path 21 shown in the figure. Then, along the direction pointing towards the center of the disk layer 10, the annular side surface 12 of the disk layer 10 is impacted point by point using the second path 22 shown in the figure and returns to the outer ring edge 13. Finally, the area between the outer edge of the annular bombardment area 15 and the edge 13 is loaded.

[0051] The first path 21, the second path 22, and the third path 23 follow the same development pattern as the shock wave and crack propagation, thus providing better crack suppression.

[0052] Of course, without considering optimal economics, after the step of sequentially impacting the area between the outer edge of the annular bombardment zone 15 and the outer ring edge 13 of the end face 11 of the disk layer 10 in the direction pointing towards the center of the disk layer 10,

[0053] Then, along the direction pointing towards the center of the disk layer 10, impact the area between the inner edge of the annular bombardment zone 15 and the inner ring edge 14 point by point.

[0054] After sequentially loading the first path 21, the second path 22, and the third path 23, the laser shock device further loads the area between the inner edge of the annular bombardment zone 15 and the inner ring edge 14 via the fourth path 24 shown in the diagram, pointing towards the center of the disk layer. At this point, the strengthening effect of the laser shock is even better.

[0055] Of course, since the temperature of the area between the inner edge of the annular bombardment zone 15 and the inner ring edge 14 is relatively high, the cracks propagated by the material rebound under high heat are much smaller than the cracks propagated by the material rebound under low heat. Therefore, the area between the inner edge of the annular bombardment zone 15 and the inner ring edge 14 may not be subjected to laser shock loading.

[0056] like Figure 5 As shown, the positions of each first laser shock spot 211 on the first path 21 are spaced apart and do not overlap; while the positions of each second laser shock spot 221 on the second path 22 are also spaced apart, and each second laser shock spot 221 is located between the two first laser shock spots 211 on the first path 21.

[0057] At this point, the impact formed on the annular side 12 of the disc layer 10 has no repeated impact points, which has a better cost advantage.

[0058] Furthermore, the third laser shock spots on the third path are also distributed at intervals to match the first laser shock spot 211 and the second laser shock spot 221 that are distributed at intervals on the annular side 12.

[0059] As an optimization of the above implementation method, the positions of the first laser impact spots 211 on the first path 21 are spaced apart and do not overlap; while the positions of the second laser impact spots 221 on the second path 22 are also spaced apart, but each overlaps with two adjacent first laser impact spots 211, such as... Figure 5 As shown. In this way, the annular side surface 12 of the disc layer 10 can form a continuously distributed impact strengthening path, resulting in a better strengthening effect.

[0060] Furthermore, the third laser shock spot on the third path is also overlapped to match the first laser shock spot 211 and the second laser shock spot 221 that are continuously overlapped on the annular side 12.

[0061] The method of first impacting the outer ring edge 13 of the disk layer with a pulsed laser beam is specifically: impacting the outer ring edge 13 of the disk layer in an oblique manner. Since the outer ring edge 13 generally has chamfers or rounded corners, impacting it perpendicular to the end face 11 of the disk layer 10 would not guarantee full coverage of the outer ring edge 13 by the laser shock wave. Therefore, this application adopts an oblique impact method to improve the strengthening effect on the outer ring edge 13.

[0062] Furthermore, since using a rigid constraint layer (such as aluminum foil or black tape) for the inclined impact at the outer ring edge 13 would lead to cumbersome processing, it is preferable to use a flexible constraint layer, such as water or inorganic salt solution, at the outer ring edge 13. Saturated inorganic salt melt is even more optimized. The reason for using an inorganic salt solution is that a high-density, transparent liquid can better constrain the diffusion of impact products, enhance the amplitude of the shock wave, and prolong the impact time. This allows the shock wave generated on the workpiece surface to propagate directionally into the workpiece, causing the distorted lattice in areas of stress within the workpiece to change more effectively under the combined action of the shock wave and the existing stress, thus improving the impact effect of the anode target.

[0063] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An anode target disk structure, characterized in that, The system includes a disk surface layer (10), a disk body (20), and a substrate layer (30); the disk surface layer (10) is fixedly connected above the disk body (20); the disk body (20) is fixedly connected above the substrate layer (30); the disk surface layer (10) includes an end face (11) and an annular side surface (12) located outside the end face (11); the end face (11) and the annular side surface (12) form an outer ring edge (13); the end face (11) has an annular bombardment area (15) that bears electron beam bombardment and generates X-rays; the anode target disk is provided with residual compressive stress impact pits formed after laser shock strengthening; the residual compressive stress impact pits are composed of the annular side surface (12) of the disk surface layer (10) and the area between the outer edge of the annular bombardment area (15) and the outer ring edge (13) in the end face (11) of the disk surface layer (10); Specifically, the pulsed laser beam impacts the target coverage area of ​​the anode target disk as follows: First, the pulsed laser beam impacts the outer ring edge of the disk surface layer; then, it impacts the annular side surface of the disk surface layer point by point along a direction away from the center of the disk surface layer; next, it returns along a direction pointing towards the center of the disk surface layer and impacts the annular side surface of the disk surface layer point by point; finally, it impacts the area between the outer edge of the annular bombardment zone and the outer ring edge of the end face of the disk surface layer in sequence along a direction pointing towards the center of the disk surface layer. The end face (11) has an inner ring edge (14) at the middle position; the annular side surface (12) has a bottom edge (16) at the bottommost position.

2. The anode target disk structure according to claim 1, characterized in that, The upper surface of the end face (11) is provided with a flexible medium as an absorption layer.

3. The anode target disk structure according to claim 2, characterized in that, The absorbent layer is aluminum foil or black adhesive.

4. The anode target disk structure according to claim 1, characterized in that, A flexible constraint layer is provided on the outer ring edge (13).

5. The anode target disk structure according to claim 4, characterized in that, The flexible constraint layer is water or an inorganic salt melt.

6. The anode target disk structure according to claim 5, characterized in that, The flexible constraint layer is a saturated inorganic salt melt.

7. The anode target disk structure according to claim 1, characterized in that, The anode target disk is a tungsten target.

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