Aluminum-scandium target material and preparation method thereof

Abstract

The invention relates to the technical field of target material preparation, and provides an aluminum-scandium target material and a preparation method thereof.The aluminum-scandium target material comprises a partition plate, a circular ring, an aluminum-scandium target blank, a back plate, an upper supporting plate and a lower supporting plate, and the Sc content of the aluminum-scandium target blank is larger than or equal to 20 at%. After diffusion welding, the flatness of the aluminum-scandium target blank is good, so that the aluminum-scandium target blank part does not need to be machined in the machining process after welding, only the back plate part needs to be machined, and the utilization rate of an alloy material and the production stability are improved. The aluminum-scandium target material prepared by the preparation method has no phenomena of corner chipping, cracking and the like, and is high in dimensional precision, small in error and high in roundness.

Description

Technical Field

[0001] The present invention relates to the technical field of target preparation, and specifically to an aluminum scandium target and a preparation method thereof. Background Art

[0002] Aluminum alloys have very broad application prospects in high-tech fields such as shipbuilding, aerospace industry, rocket missiles, and nuclear energy. Based on existing aluminum alloys, a series of aluminum scandium alloys have been developed by adding trace amounts of scandium, such as ultra-high strength and high toughness aluminum alloys, high strength and corrosion-resistant aluminum alloys, and high strength aluminum alloys for resisting neutron irradiation. These aluminum scandium alloys have very attractive application prospects in the aerospace, nuclear energy, and shipbuilding industries due to their excellent comprehensive properties.

[0003] Aluminum scandium alloys have better strength and heat resistance due to the addition of scandium. However, a higher Sc content will affect the processing performance of aluminum scandium alloys because Sc will form brittle Al3Sc precipitation phases in aluminum, and the higher the Sc content, the greater the brittleness of the target blank. This leads to a higher processing hardening rate of aluminum scandium alloys with a high Sc content during machining, more obvious local stress concentration during deformation, and is prone to initiate microcracks or chipping.

[0004] Furthermore, when diffusion welding an AlSc alloy target blank with a high Sc content to a backing plate by hot isostatic pressing, in order to improve the welding rate, a pressurized and medium-high temperature method needs to be used, which easily causes the AlSc alloy target blank to deform due to welding stress and internal stress. Not only does it require additional machining correction, but if the direction of machining correction is not selected properly, it will exacerbate the non-uniform deformation of the target blank, and even cause the target blank to wrinkle or crack, resulting in waste of raw materials.

[0005] CN111889869B discloses a welding method for high-purity rare earth and alloy targets, and the steps are as follows: gear the welding surfaces of the rare earth target blank and the backing plate, and perform back plating treatment on the toothed surface; coat a protective layer on the non-welding surface of the rare earth target blank; set an intermediate layer at the welding interface of the two; prepare a welding jacket, and coat a protective layer on the inner surface of the jacket; assemble the rare earth target blank, the intermediate layer, and the backing plate into the jacket, and perform electron beam seal welding on the jacket to obtain a sealed welding target; perform hot isostatic pressing diffusion welding on the sealed welding target to obtain a high-purity rare earth target. As can be seen from Figure 5 of its specification drawings, the assembly of the jacket is mainly to improve the welding rate and welding strength. However, when this method is applied to aluminum scandium targets, especially aluminum scandium targets with a high Sc content, it is easy to cause the aluminum scandium target blank to deform or even crack due to welding stress and internal stress.

[0006] CN 111185659 A discloses a diffusion welding method for a titanium target and a backplate and a titanium target assembly obtained thereby. The sheathing assembly is as follows: Subsequently, the titanium target is placed in the groove of the backplate, and gaskets are arranged around the titanium target to complete the assembly process. Then, the whole is placed in an aluminum sheath. It can be seen from the accompanying specification that this solution is designed to improve the welding bond strength. The gaskets improve the welding bond strength between the titanium target and the backplate, effectively avoiding abnormal grain growth. This sheathing state only uses gaskets to improve the uniform pressure on the target. However, for aluminum scandium targets with a high Sc content, this method still cannot completely avoid the deformation or even cracking of the aluminum scandium target blank due to welding stress and internal stress.

[0007] Based on this, the technical problem to be solved in this case is: how to solve the problems of easy deformation and cracking of aluminum scandium targets during machining and diffusion welding. Summary of the Invention

[0008] To solve the above technical problems, the present invention provides an aluminum scandium target and a preparation method thereof. The preparation method can avoid deformation or cracking of the aluminum scandium target blank during machining and diffusion welding. After diffusion welding, the flatness of the aluminum scandium target blank is good. Therefore, during the subsequent machining process, only the backplate part needs to be machined, and the aluminum scandium target blank part does not need to be machined, increasing the utilization rate of the alloy material and the production stability. The aluminum scandium target obtained by this preparation method not only has no phenomena such as chipping and cracking, but also has high dimensional accuracy, small error, and high roundness.

[0009] The technical solution of the present invention is:

[0010] A method for preparing an aluminum scandium target, wherein the Sc content of the aluminum scandium target blank is ≥20 at%, and the method includes a partition plate, a ring, an aluminum scandium target blank, a backplate, an upper support plate, and a lower support plate. The preparation method includes the following steps:

[0011] Step 1: Use machining to prepare a groove on the backplate, and use wire cutting to prepare an aluminum scandium target blank with dimensions matching the groove.

[0012] Step 2: Sheathing assembly. Arrange and place the lower support plate, the backplate, the aluminum scandium target blank, the ring, the upper support plate, and the partition plate in sequence into the sheath and seal and degas. The aluminum scandium target blank is placed in the groove of the backplate, and the ring is placed on the backplate and surrounds the part of the aluminum scandium target blank protruding from the groove.

[0013] Step 3: Perform diffusion welding on the sheath in Step 2 to obtain a semi-finished product.

[0014] Step 4: Machine the backplate part of the semi-finished product to obtain a finished target.

[0015] The present invention adjusts the size of the aluminum scandium target blank by wire cutting, and performs multi-point positioning on the side surface of the aluminum scandium target blank during wire cutting, thereby reducing the probability of cracking and chipping due to mechanical vibration. At the same time, it is beneficial to improve the dimensional accuracy and roundness and reduce errors. In addition, the jacket assembly of the present invention effectively improves the flatness of the aluminum scandium target blank after diffusion welding by "shallowly embedding" the aluminum scandium target blank in the back plate, and restricts the circumferential deformation of the aluminum scandium target blank and releases the welding stress and internal stress during the diffusion welding process through the ring, which can effectively inhibit the deformation of the aluminum scandium target blank and prevent cracking. It also restricts the axial deformation through the upper support plate and the lower support plate to further inhibit the deformation of the aluminum scandium target blank, and prevents the target material from deforming with the position of the degassing port of the jacket through the partition plate. The ring, the upper support plate and the lower support plate cooperate to inhibit the deformation of the aluminum scandium target blank, effectively improving the yield rate of the prepared aluminum scandium target material.

[0016] In the above method for preparing an aluminum scandium target, the depth of the groove is 0.5 - 2 mm, including but not limited to 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2.0 mm.

[0017] In the above method for preparing an aluminum scandium target, the diameter of the back plate is 300 - 400 mm, including but not limited to 300 mm, 320 mm, 350 mm, 380 mm, 400 mm; the thickness is 9 - 11 mm, including but not limited to 9 mm, 10 mm, 11 mm; the diameter of the target blank is 200 - 340 mm, including but not limited to 200 mm, 250 mm, 300 mm, 340 mm; the thickness is 5 - 10 mm, including but not limited to 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm.

[0018] In the above method for preparing an aluminum scandium target, after the jacket assembly in step 2, the upper end surface of the ring is lower than the upper end surface of the aluminum scandium target blank and the distance is 0.5 - 1.0 mm, including but not limited to 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm.

[0019] In the above method for preparing an aluminum scandium target, the inner diameter of the ring is the outer diameter of the aluminum scandium target blank + 0.5 - 2 mm, including but not limited to 0.5 mm, 0.7 mm, 1.0 mm, 1.2 mm, 1.5 mm, 1.8 mm, 2.0 mm; the outer diameter of the ring is the same as the outer diameter of the back plate.

[0020] In the jacket assembly in step 2 of the above method for preparing an aluminum scandium target, an isolation layer for facilitating jacket demolding is further included; isolation layers are provided at the joints of the partition plate, the ring, the aluminum scandium target blank, the back plate and the support plate.

[0021] In the above method for preparing an aluminum scandium target, the temperature of the diffusion welding is 400-600 °C, including but not limited to 400 °C, 450 °C, 500 °C, 550 °C, 600 °C; the pressure is 100-160 Mpa, including but not limited to 100 Mpa, 110 Mpa, 120 Mpa, 130 Mpa, 140 Mpa, 150 Mpa, 160 Mpa; and the heat preservation and pressure maintenance are 2-5 h, including but not limited to 2 h, 3 h, 4 h, 5 h.

[0022] In the above method for preparing an aluminum scandium target, the flatness of the semi-finished product obtained in Step 3 is ≤0.2 mm.

[0023] In the above method for preparing an aluminum scandium target, the degassing process in Step 2 is to evacuate for 3-6 h at a temperature of 350-550 °C until the vacuum degree inside the jacket is less than 4×10 -3 Pa and then seal the opening.

[0024] In addition, the present application also discloses an aluminum scandium target prepared by the above method for preparing an aluminum scandium target, with a welding strength ≥100 MPa and a target binding rate ≥99%.

[0025] One of the technical solutions in the above technical solutions of the present invention has at least the following advantages or beneficial effects:

[0026] 1. By wire cutting, the present invention can improve the dimensional accuracy and roundness of the aluminum scandium target blank, reduce the error, make it more matching in the subsequent jacket assembly, and at the same time, wire cutting can also reduce the probability of cracking and chipping of the aluminum scandium target blank due to mechanical vibration.

[0027] 2. The jacket assembly of the present invention can make the flatness of the aluminum scandium target blank after diffusion welding reach below 0.2 mm. Therefore, in the subsequent machining, it is only necessary to machine the backplane part without machining the aluminum scandium target blank, which not only increases the utilization rate of raw materials and improves the stability of the finished product, but also reduces the probability of cracking and chipping of the aluminum scandium target blank.

[0028] 3. The jacket assembly of the present invention can ensure that the flatness of the aluminum scandium target blank after welding is ≤0.2 mm on the premise of meeting the welding strength ≥100 MPa and the target binding rate ≥99%. Description of the Drawings

[0029] Figure 1 It is a schematic diagram of the jacket assembly of the embodiment of the present invention;

[0030] Figure 2 It is a schematic diagram of the jacket assembly of Comparative Example 1 of the present invention.

[0031] Description of the Reference Numerals:

[0032] Partition 1; Ring 2; Aluminum scandium target blank 3; Backplate 4; Upper support plate 5; Lower support plate 6; Isolation layer 7; Sheath 8. Specific implementation mode

[0033] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work belong to the protection scope of the present invention.

[0034] In the following examples, unless otherwise specified:

[0035] 1. The diameter of the backplate 4 is 352 mm and the thickness is 8 mm; the diameter of the aluminum scandium target blank 3 is 250 mm and the thickness is 5 mm; the diameters of the upper support plate 5 and the lower support plate 6 are 352 mm and the thickness is 20 mm.

[0036] 2. The material of the isolation layer 7 is graphite paper; the material of the ring 2 is stainless steel; the material of the isolation layer 7 is graphite paper; the material of the sheath 8 is aluminum alloy.

[0037] Example 1

[0038] A method for preparing an aluminum scandium target, wherein the Sc content of the aluminum scandium target blank 3 is 20 at%, including a partition 1, a ring 2, an aluminum scandium target blank 3, a backplate 4, an upper support plate 5 and a lower support plate 6, and further including an isolation layer 7 for facilitating the demolding of the sheath 8;

[0039] The preparation method includes the following steps:

[0040] Step 1: Use machining to prepare a groove with a diameter of 250 mm and a depth of 0.5 mm on the backplate 4, and use wire cutting to prepare an aluminum scandium target blank 3 with dimensions matching the groove;

[0041] Step 2: Sheath 8 assembly, arrange and place the lower support plate 6, backplate 4, aluminum scandium target blank 3, ring 2, upper support plate 5, and partition 1 in the sheath 8 in sequence. Among them, the aluminum scandium target blank 3 is placed in the groove of the backplate 4, and the ring 2 is placed on the backplate 4 and surrounds the protruding part of the aluminum scandium target blank 3; isolation layers 7 are provided at the joints of the partition 1, ring 2, aluminum scandium target blank 3, backplate 4, and support plate; in this embodiment, preferably, after the sheath 8 is assembled, the upper end surface of the ring 2 is lower than the upper end surface of the aluminum scandium target blank 3 and the distance is 0.5 mm; the inner diameter of the ring 2 is 250.5 mm, and the outer diameter of the ring 2 is the same as the outer diameter of the backplate 4; for the specific structure, refer to Figure 1 ;

[0042] Then, at a temperature of 350 °C, the jacket 8 is evacuated for 6 h until the vacuum degree inside the jacket 8 is less than 4×10 -3 Pa, and then it is sealed;

[0043] Step 3: Put the degassed jacket 8 into a hot isostatic press for diffusion welding, where the temperature is 400 °C, the pressure is 100 Mpa, and keep the temperature and pressure for 3 h to obtain a semi-finished product;

[0044] Step 4: Machine the backplane 4 part of the semi-finished product according to the drawing dimensions to obtain the finished target.

[0045] Example 2

[0046] A method for preparing an aluminum scandium target is basically the same as that in Example 1, except that: the Sc content of the aluminum scandium target blank 3 is 25 at%

[0047] Example 3

[0048] A method for preparing an aluminum scandium target is basically the same as that in Example 1, except that: Step 1: Use machining to prepare a groove with a diameter of 250 mm and a depth of 1 mm on the backplane 4.

[0049] Example 4

[0050] A method for preparing an aluminum scandium target is basically the same as that in Example 1, except that: Step 1: Use machining to prepare a groove with a diameter of 250 mm and a depth of 2.5 mm on the backplane 4.

[0051] Example 5

[0052] A method for preparing an aluminum scandium target is basically the same as that in Example 1, except that: Step 1: Use machining to prepare a groove with a diameter of 250 mm and a depth of 3.0 mm on the backplane 4.

[0053] Example 6

[0054] A method for preparing an aluminum scandium target is basically the same as that in Example 1, except that: in this example, preferably, after the jacket 8 is assembled, the upper end surface of the ring 2 is lower than the upper end surface of the aluminum scandium target blank 3 and the distance is 1 mm; the inner diameter of the ring 2 is 252 mm, and the outer diameter of the ring 2 is the same as the outer diameter of the backplane 4.

[0055] Example 7

[0056] A method for preparing an aluminum scandium target is basically the same as that in Example 2, except that: Step 3: Put the degassed jacket 8 into a hot isostatic press for diffusion welding, where the temperature is 600 °C, the pressure is 160 Mpa, and keep the temperature and pressure for 3 h to obtain a semi-finished product.

[0057] Comparative Example 1

[0058] A method for preparing an aluminum scandium target is basically the same as that of Example 1, except that: Step 2: Assembly of the jacket 8. The back plate 4, the aluminum scandium target blank 3 and the ring 2 are arranged and placed in the jacket 8 in sequence. Among them, the aluminum scandium target blank 3 is placed in the groove of the back plate 4, and the ring 2 is placed on the back plate 4 and surrounds the protruding part of the aluminum scandium target blank 3; isolation layers 7 are provided at the joints of the ring 2, the aluminum scandium target blank 3 and the back plate 4; in this embodiment, preferably, after the assembly of the jacket 8, the upper end surface of the ring 2 is lower than the upper end surface of the aluminum scandium target blank 3 and the distance is 0.5 mm; the inner diameter of the ring 2 is 250.5 mm, and the outer diameter of the ring 2 is the same as the outer diameter of the back plate 4. Refer to Figure 2 .

[0059] Detection: Perform C-scan on the semi-finished products obtained by diffusion welding in Examples 1 to 7 and Comparative Example 1.

[0060] Table 1: Flatness, welding rate and welding strength of semi-finished products

[0061]

[0062] Result analysis:

[0063] Aluminum scandium target blanks with high flatness, high welding rate and high welding strength can be prepared in Examples 1 to 3. The reason is that the ring and the groove, as well as the upper support plate and the lower support plate effectively inhibit the deformation of the aluminum scandium target blank. And in the subsequent machining, there is no need to machine the aluminum scandium target blank, and only the back plate part needs to be machined.

[0064] In Examples 4 and 5, the depth of the aluminum scandium target blank buried in the back plate is higher than that in Example 3, and the deformation amount during diffusion welding is larger, resulting in a flatness slightly higher than 0.2 mm.

[0065] In Example 7, the Sc content of the aluminum scandium target blank is higher and the temperature and pressure of diffusion welding are greater, and there is still no problem of cracking of the aluminum scandium target blank during diffusion welding. And in the subsequent machining, there is no need to machine the aluminum scandium target blank, and only the back plate part needs to be machined.

[0066] For Comparative Example 1, the flatness of the jacket assembly method exceeds the allowable range, and additional machining of the aluminum scandium target blank is required, increasing the risk of cracking and scrapping. The reason is that the lack of the upper support plate and the lower support plate restricts the axial deformation.

[0067] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the present invention is defined by the claims and their equivalents.

Claims

1. A method for preparing an aluminum scandium target, characterized in that, The Sc content of the aluminum scandium target blank is ≥20 at%, and it includes a partition plate, a ring, an aluminum scandium target blank, a back plate, an upper support plate, and a lower support plate. The preparation method includes the following steps: Step 1: Use machining to prepare a groove on the back plate, and use wire cutting to prepare an aluminum scandium target blank with dimensions matching the groove. Step 2: Sheath assembly. Arrange and place the lower support plate, back plate, aluminum scandium target blank, ring, upper support plate, and partition plate in sequence into the sheath and seal it for degassing. Among them, the aluminum scandium target blank is placed in the groove of the back plate, and the ring is placed on the back plate and surrounds the part of the aluminum scandium target blank protruding from the groove; the ring is used to limit the circumferential deformation of the aluminum scandium target blank; the upper support plate and the lower support plate limit the axial deformation of the aluminum scandium target blank. Step 3: Perform diffusion welding on the sheath in Step 2 to obtain a semi-finished product. Step 4: Machine the back plate part of the semi-finished product to obtain a finished target material.

2. The method for preparing an aluminum scandium target according to claim 1, wherein The depth of the groove is 0.5 - 2 mm.

3. The method for preparing an aluminum scandium target according to claim 1, characterized in that, The diameter of the back plate is 300 - 400 mm, and the thickness is 9 - 11 mm; the diameter of the target blank is 200 - 340 mm, and the thickness is 5 - 10 mm.

4. The method for preparing an aluminum scandium target according to claim 1, wherein, After the sheath assembly in Step 2, the upper end face of the ring is lower than the upper end face of the aluminum scandium target blank and the distance is 0.5 - 1.0 mm.

5. The method for preparing an aluminum scandium target according to claim 1, wherein The inner diameter of the ring is the outer diameter of the aluminum scandium target blank + 0.5 - 2 mm, and the outer diameter of the ring is the same as the outer diameter of the back plate.

6. The method for preparing an aluminum scandium target according to claim 1, characterized in that, The sheath assembly in Step 2 also includes an isolation layer for facilitating the demolding of the sheath; isolation layers are provided at the joints of the partition plate, ring, aluminum scandium target blank, back plate, and support plate.

7. The method for preparing an aluminum scandium target according to claim 1, wherein The temperature of the diffusion welding is 400 - 600 °C, the pressure is 100 - 160 Mpa, and the heat preservation and pressure holding time is 2 - 5 h.

8. The method for preparing an aluminum scandium target according to claim 1, wherein For the semi-finished product obtained in Step 3, its flatness ≤0.2 mm.

9. The method for preparing an aluminum scandium target according to claim 1, wherein, The degassing process in step 2 is to evacuate for 3 - 6 h at a temperature of 350 - 550 °C until the vacuum degree inside the jacket is less than 4*10 -3 Pa and then seal the opening.

10. An aluminum scandium target, characterized in that, Prepared by using the aluminum scandium target material preparation method according to any one of claims 1 - 9.

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