An aluminum-scandium alloy target blank and a method of making the same

Abstract

The application provides an aluminum-scandium alloy target blank and a preparation method thereof, and belongs to the technical field of aluminum-scandium alloy preparation. The preparation raw material corresponding to the element composition of the aluminum-scandium alloy target blank is melted to obtain an alloy melt; the alloy melt is pressed into a mold to perform rapid filling; the filling speed is 0.1-20 m / s, and the filling time is 0.01-2 s; after the filling is completed, pressure maintaining is performed, the alloy melt in the mold rapidly solidifies to obtain the aluminum-scandium alloy target blank; and the pressure maintaining pressure is 10-200 MPa. The application increases the flowability of the aluminum-scandium alloy melt through rapid filling, guarantees the integrity of the cast blank, effectively refines the grains through high-pressure die casting, improves the density, and obtains an aluminum-scandium target blank which is uniform in composition, compact in structure, and excellent in processing performance. The results of the examples show that the relative density of the aluminum-scandium target blank prepared by the application is 95.5-99.9%, and the oxygen content is 60-300 ppm.

Description

Technical Field

[0001] This invention belongs to the field of aluminum-scandium alloy preparation technology, specifically relating to an aluminum-scandium alloy target blank and its preparation method. Background Technology

[0002] Filters fabricated from aluminum nitride (AlN) thin films suffer from drawbacks such as insufficient piezoelectric coefficient and electromechanical coupling coefficient. However, AlScN thin films doped with scandium (Sc) can significantly improve parameters such as piezoelectric coefficient and electromechanical coupling coefficient, and are compatible with complementary metal-oxide-semiconductor (CMOS) processes. Therefore, AlScN thin films have become key materials in fields such as 5G high-frequency filters, microelectromechanical systems (MEMS), and semiconductor chips. AlScN thin films are mainly prepared using nitrogen as the reactive gas via sputtering AlSc target vapor deposition. Therefore, factors such as the Sc content, purity, compositional uniformity, and density of the AlSc target blank are crucial to the performance of AlScN thin films.

[0003] Due to the significant difference in melting points between aluminum and scandium, a rare-earth metal, preparing AlSc target blanks with low segregation, high density, and high Sc content presents a major challenge. Existing preparation technologies mainly fall into two categories: powder metallurgy and smelting and casting. While powder metallurgy can produce AlSc target blanks with high Sc content, the strong gas absorption characteristics of aluminum alloy powder and the high chemical reactivity of scandium result in persistently high oxygen content in the aluminum-scandium target blanks, severely impacting the performance of sputtered thin films. Furthermore, the target blanks prepared by powder metallurgy sintering require subsequent hot isostatic pressing to improve density. Although the improved density can reach 90–98%, it is still lower than that of as-cast alloys, and the process is complex and costly. Although the melting and casting method has the advantages of high efficiency, low cost, high ingot density and low oxygen content, the low solid solubility of Sc in aluminum and the widening of the solid-liquid phase temperature range with increasing Sc content lead to obvious compositional segregation and coarse secondary dendrite structures in AlSc target billets prepared by conventional melting and casting. Furthermore, as the Sc content increases, brittle phases such as Al3Sc, Al2Sc, and AlSc precipitate, reducing the plasticity of AlSc alloys. In addition, for large-sized targets, the billets obtained by conventional casting have severe internal defects such as shrinkage cavities and porosity, making the billets prone to cracking and difficult to process in subsequent steps.

[0004] CN112548069A discloses a method for preparing AlSc alloy targets by liquid forging of AlSc alloy melt followed by annealing. This method involves low-speed filling, resulting in a clear sequence of solidification between the inner and outer layers of the alloy. The outer hard shell, which solidifies first, undergoes plastic deformation under extrusion, leading to high internal stress in the casting. Furthermore, the uneven solidification between the inner and outer layers results in different pressure conditions during solidification, leading to significant differences in solidification conditions between the inner and outer parts of the billet. This, in turn, results in uneven internal microstructure and composition distribution within the billet. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide an aluminum-scandium alloy target blank and its preparation method. The method of this invention can produce aluminum-scandium target blanks with uniform composition, dense microstructure, and excellent processing performance. Furthermore, this method has a short process cycle and is suitable for industrial production.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0007] This invention provides a method for preparing an aluminum-scandium alloy target blank, comprising the following steps:

[0008] Based on the elemental composition of the aluminum-scandium alloy target billet, the raw materials are melted to obtain the alloy melt;

[0009] The alloy melt is pressed into a mold for rapid filling; the filling speed is 0.1–20 m / s, and the filling time is 0.01–2 s.

[0010] After the filling process is completed, pressure is maintained, and the alloy melt in the mold solidifies rapidly to obtain the aluminum-scandium alloy target blank; the pressure maintained is 10-200 MPa.

[0011] Preferably, the pressure holding time is 1 to 150 seconds.

[0012] Preferably, the raw materials for preparation include an aluminum-scandium master alloy, or include pure aluminum and high-purity scandium, or include an aluminum-scandium master alloy and pure aluminum.

[0013] Preferably, the melting temperature is 655–1600°C.

[0014] Preferably, the melting is carried out under vacuum or inert gas protection.

[0015] Preferably, a salt covering agent is added during the smelting process, and the mass ratio of the salt covering agent to the raw materials is 1:20 to 500.

[0016] Preferably, before pressing the alloy melt into the mold, the mold is preheated;

[0017] The preheating temperature is 80–300°C, and the preheating time is 10–60 min.

[0018] Preferably, before preheating the mold, a release agent is sprayed onto the inner surface of the mold.

[0019] Preferably, the scandium content in the aluminum-scandium alloy target blank is 2-70 wt%, and the aluminum content is 30-98 wt%.

[0020] The present invention also provides an aluminum-scandium alloy target blank prepared by the preparation method described above, wherein the aluminum-scandium alloy target blank has a relative density of 95.5-99.9% and an oxygen content of 60-300 ppm.

[0021] This invention provides a method for preparing an aluminum-scandium alloy target blank, comprising the following steps: melting the raw materials according to the elemental composition of the aluminum-scandium alloy target blank to obtain an alloy melt; pressing the alloy melt into a mold for rapid filling; the filling speed is 0.1-20 m / s, and the filling time is 0.01-2 s; after the filling is completed, holding pressure is applied, and the alloy melt in the mold rapidly solidifies to obtain the aluminum-scandium alloy target blank; the holding pressure is 10-200 MPa. This application increases the fluidity of the aluminum-scandium alloy melt through rapid filling, which facilitates filling the alloy mold cavity, ensuring the integrity of the cast billet and achieving excellent dimensional accuracy. Rapid solidification under high pressure reduces the solidification time difference between the inside and outside of the melt, improves the consistency of solidification conditions, and reduces solidification stress. Furthermore, it dissolves Sc atoms in the α-Al matrix, reducing secondary phase precipitation and further minimizing microsegregation. Simultaneously, pressure solidification effectively refines the grains, reducing defects such as shrinkage cavities and porosity, and increasing density. This results in aluminum-scandium target billets with fine grains, uniform composition and microstructure, high density, and excellent processing performance. It significantly reduces deformation and cracking behavior in the preparation of large-size aluminum-scandium targets, providing a solution for preparing 12-inch high-Sc-content aluminum-scandium alloy target billets. The preparation method provided in this application is low-cost, has a short process cycle, high yield, and is easy to industrialize.

[0022] The present invention also provides an aluminum-scandium alloy target blank prepared by the preparation method described above. Results of the embodiments show that the aluminum-scandium alloy target blank prepared by the present invention has high relative density and low oxygen content, with a relative density of 95.5–99.9% and an oxygen content of 60–300 ppm. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 A schematic diagram of the die-casting mold structure for aluminum-scandium alloy target blanks;

[0025] Figure 2 The images shown are SEM images of the secondary precipitates (a) and the fracture morphology after tensile testing (b) of the aluminum-scandium alloy target billet in Example 1.

[0026] Figure 3SEM images (a) and (b) of the aluminum-scandium alloy target billet after casting and die casting in Example 2;

[0027] Figure 4 SEM images of the secondary precipitates (a) and fracture morphology after tensile testing (b) of the aluminum-scandium alloy target billet in Comparative Example 1.

[0028] Figure 5 The stress-strain curves are for comparative examples and Example 1. Detailed Implementation

[0029] This invention provides a method for preparing an aluminum-scandium alloy target blank, comprising the following steps:

[0030] Based on the elemental composition of the aluminum-scandium alloy target billet, the raw materials are melted to obtain the alloy melt;

[0031] The alloy melt is pressed into a mold for rapid filling; the filling speed is 0.1–20 m / s, and the filling time is 0.01–2 s.

[0032] After the filling process is completed, pressure is maintained, and the alloy melt in the mold solidifies rapidly to obtain the aluminum-scandium alloy target blank; the pressure maintained is 10-200 MPa.

[0033] In this invention, unless otherwise specified, all raw materials and equipment used are commercially available products well known in the art.

[0034] This invention relates to the elemental composition of aluminum-scandium alloy target blanks, and involves melting the raw materials to obtain an alloy melt.

[0035] In this invention, the raw materials preferably include an aluminum-scandium master alloy, or include pure aluminum and high-purity scandium, or include an aluminum-scandium master alloy and pure aluminum. In this invention, the purity of the pure aluminum is preferably 99.996% or higher; the purity of the high-purity scandium is preferably 99.99% or higher. In a specific embodiment of this invention, pure aluminum and high-purity scandium are used as the raw materials. In this invention, the composition of the raw materials is determined based on the elemental composition of the aluminum-scandium alloy target blank. The scandium content in the aluminum-scandium alloy target blank can be selected according to different needs for preparing aluminum nitride thin films. The scandium content in the aluminum-scandium alloy target blank is preferably 2-70 wt%, and the aluminum content is preferably 30-98 wt%.

[0036] In this invention, a salt covering agent is preferably added during the smelting process. The invention does not specify the type of salt covering agent; any salt covering agent well-known in the art can be used. In embodiments of this invention, the salt covering agent is a commercially available salt covering agent composed of chloride and fluoride salts. In this invention, the mass ratio of the salt covering agent to the raw materials is preferably 1:20–500, more preferably 1:150–350, and even more preferably 1:250. During heating, the salt covering agent floats above the melt, serving to insulate and prevent gases such as oxygen and hydrogen from entering the melt.

[0037] In this invention, the melting temperature is preferably 655–1600°C, more preferably 900–1500°C, and even more preferably 1000–1400°C. The melting time is preferably 10–60 min, more preferably 30–50 min. In this invention, the melting is preferably carried out under vacuum or inert gas protection. Melting in a vacuum or inert environment can prevent gases such as oxygen and hydrogen from entering the melt, reducing porosity in the aluminum-scandium alloy target billet and the metal oxides generated after reaction with gases. This invention does not have special requirements for the melting method; operations well known in the art can be used to ensure complete melting of the alloy. In an embodiment of this invention, the melting process is as follows: the raw materials are placed in a melting crucible, a salt covering agent is added, the crucible containing the materials is placed in a resistance melting furnace under inert atmosphere protection, heated to the melting temperature and held at that temperature to obtain the alloy melt.

[0038] After obtaining the alloy melt, the present invention presses the alloy melt into a mold for rapid filling.

[0039] In this invention, the mold preferably includes an inner gate and overflow groove, a runner and a hollow cavity portion (e.g. Figure 1 (As shown). In this invention, the overflow groove is preferably designed according to the requirements of the target material size to obtain different die castings. The presence of the ingate and overflow groove not only ensures uniformity of the edge composition but also serves for venting, preventing air bubbles in the casting due to top air and ensuring complete filling of the casting.

[0040] In this invention, before pressing the alloy melt into the mold, it is preferable to spray a release agent onto the inner surface of the mold, preferably MS-605 release agent. The release agent acts as a lubricant at high temperatures, increasing melt fluidity, reducing porosity, preventing sticking, and extending mold life.

[0041] In this invention, before pressing the alloy melt into the mold, it is preferable to preheat the mold. Preferably, a release agent is sprayed first, followed by preheating. The preheating temperature is preferably 80–300°C, more preferably 150–250°C, and the preheating time is preferably 10–60 minutes, more preferably 30–50 minutes. Because the solidification of the alloy melt releases heat, a temperature difference arises between the alloy melt and the mold temperature, generating thermal stress at the mold wall. This can lead to deformation, cracks, and reduced load-bearing capacity in the casting. This invention avoids these problems by preheating the mold.

[0042] This invention preferably utilizes die-casting equipment to press molten alloy into a mold. In this invention, the die-casting equipment is equipped with a gating system, which includes a runner. Specifically, the molten alloy is poured into the feed inlet above the runner of the die-casting equipment, and then pressed into the mold by a punch at a certain speed. In this invention, before pouring the molten alloy into the feed inlet above the runner, it is preferable to preheat the runner. In this invention, the preheating temperature of the runner is preferably 180–600°C, more preferably 250–350°C, and the preheating time is preferably 10–60 minutes, more preferably 30–50 minutes. By preheating the runner, this invention avoids the loss of fluidity caused by excessive temperature differences, which can lead to problems such as deformation, cracking, and reduced load-bearing capacity in the casting.

[0043] In this invention, the filling speed is 0.1–20 m / s, preferably 1–10 m / s, more preferably 3–5 m / s, and the filling time is 0.01–2 s, preferably 0.1–1 s, more preferably 0.3–0.8 s. This invention, through rapid filling, increases the fluidity of the aluminum-scandium alloy melt, which is beneficial for filling the alloy mold cavity, ensuring the integrity of the cast billet, and achieving excellent dimensional accuracy.

[0044] After the filling process is completed, the present invention performs pressure holding, and the alloy melt in the mold solidifies rapidly to obtain the aluminum-scandium alloy target blank.

[0045] In this invention, the holding pressure is 10-200 MPa, preferably 50-180 MPa, and more preferably 60-120 MPa. The holding pressure described in this application is a boosting pressure, where after the molten metal fills the mold cavity, the punch applies a set pressure for a certain period, causing the molten metal to solidify under high pressure. The boosting pressure directly affects the quality of the die-casting. A reasonable boosting pressure can reduce defects such as shrinkage cavities, thereby achieving high density. However, excessively high boosting pressure can cause plastic deformation of the pre-solidified outer shell, increasing internal stress in the casting and reducing the mold's service life. This invention does not have special requirements for the holding pressure operation method; operations well-known in the art can be used. Continuing to apply pressure after the alloy melt fills the mold allows the aluminum-scandium alloy melt to solidify and crystallize under pressure. This can rapidly solidify to obtain a supersaturated solid solution, reducing segregation; it can also solidify under pressure to obtain fine grains, refining the microstructure; and it can eliminate some defects such as shrinkage cavities and porosity caused by solidification shrinkage.

[0046] In this invention, the holding time is preferably 1 to 150 seconds, more preferably 8 to 20 seconds. This invention controls the holding time to ensure that the center of the die-cast part is completely solidified before releasing the pressure.

[0047] In this invention, after the alloy melt solidifies, it is removed, preferably including cutting off the ingate and overflow groove. The presence of the ingate and overflow groove is to ensure uniform composition at the edges, vent air, prevent air bubbles caused by top air, and ensure complete filling of the casting.

[0048] The present invention also provides an aluminum-scandium alloy target blank prepared by the preparation method described above, wherein the relative density of the aluminum-scandium alloy target blank is 95.5-99.9%, preferably 98.3-99.6%, and the oxygen content is 60-300 ppm, preferably 61-145 ppm.

[0049] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments. The described embodiments are only some embodiments of the present invention, and not all embodiments. Any modifications, equivalent substitutions, improvements, etc., made to the embodiments of the present invention based on the technical essence and general principles of the present invention without creative effort should be within the protection scope of the present invention.

[0050] Example 1

[0051] Weigh 1800g of metallic aluminum (99.996% purity) and 200g of metallic scandium (99.99% purity) according to a scandium content of 10wt% and place them in a melting crucible. Add 8g of a salt covering agent composed of commercially available chloride and fluoride salts. Place the crucible in an argon-atmosphere protected resistance melting furnace and heat to 1000℃, holding for 15 minutes to obtain an alloy melt. Evenly spray MS-605 release agent onto the surface of the die-casting mold and heat the mold and runner to 180℃ using a mold temperature controller, holding for 30 minutes. Quickly pour the alloy melt into the feed inlet above the runner of the die-casting equipment. Start the die-casting device; the alloy melt is pressed into the mold by the punch at a speed of 3m / s for rapid filling, with a filling time of 0.9s. After the filling process is completed, the alloy melt is held under a pressure of 70MPa for 5 seconds and then removed from the mold. It is then air-cooled at room temperature. After it has completely cooled, the inner gate and overflow groove and other venting and overflow systems are cut off to obtain an 8-inch, 10mm thick aluminum scandium alloy die-casting target blank.

[0052] Example 2

[0053] Weigh out 1600g of metallic aluminum (99.996% purity) and 400g of metallic scandium (99.99% purity) according to a scandium content of 20wt% and place them in a melting crucible. Add 8g of a salt covering agent composed of commercially available chloride and fluoride salts. Place the crucible in an argon-atmosphere protected resistance melting furnace and heat to 1200℃, holding for 15 minutes to obtain the alloy melt. Evenly spray MS-605 release agent on the surface of the die-casting mold and heat the mold and runner to 210℃ using a mold temperature controller, holding for 30 minutes. Quickly pour the alloy melt into the feed port above the runner of the die-casting equipment, start the die-casting device, and the alloy melt is pressed into the mold by the punch at a speed of 3m / s for rapid filling, with a filling time of 0.9s. After the filling process is completed, the alloy melt is held under a pressure of 100MPa for 10 seconds and then removed from the mold. It is then air-cooled at room temperature. After it has completely cooled, the inner gate and overflow groove and other venting and overflow systems are cut off to obtain an 8-inch, 10mm thick aluminum scandium alloy die-casting target blank.

[0054] Example 3

[0055] Weigh out 1425g of metallic aluminum (99.996% purity) and 1075g of metallic scandium (99.99% purity) according to a scandium content of 43wt% and place them in a melting crucible. Add 10g of a commercially available salt covering agent composed of chloride and fluoride salts. Place the crucible in an argon-atmosphere-protected resistance melting furnace and heat to 1400℃, holding for 15 minutes to obtain the alloy melt. Evenly spray MS-605 release agent onto the surface of the die-casting mold and heat the mold and runner to 300℃ using a mold temperature controller, holding for 30 minutes. Quickly pour the alloy melt into the feed inlet above the runner of the die-casting equipment. Start the die-casting device, and the alloy melt is pressed into the mold by the punch at a speed of 5m / s for rapid filling, with a filling time of 0.16s. After the filling process is completed, the alloy melt is held under a pressure of 120MPa for 15s and then removed from the mold. It is then air-cooled at room temperature. After it has completely cooled, the inner gate and overflow groove and other venting and overflow systems are cut off to obtain a 12-inch aluminum scandium alloy die-casting target blank with a thickness of 10mm.

[0056] Comparative Example 1

[0057] Weigh 1800g of metallic aluminum (99.996% purity) and 200g of metallic scandium (99.99% purity) and place them in an induction melting furnace under argon atmosphere protection. Induction heat to 1000℃ and hold for 15 minutes to obtain an alloy melt. Place the mold to be cast in a muffle furnace and heat to 180℃ and hold for 30 minutes. Remove the mold and pour in the aluminum-scandium alloy melt. Cool and solidify the ingot at room temperature to obtain an aluminum-scandium target billet.

[0058] The aluminum scandium target blanks were sampled and subjected to SEM and EDS for surface micromorphology observation, second phase and composition detection, and tensile property characterization. The relative density of the aluminum scandium alloy target blanks was determined using the Archimedes displacement method, and the oxygen content was determined using the inert gas pulsed infrared thermal conductivity method. The test results of the examples and comparative examples are shown in Table 1.

[0059] Table 1 Performance tests of the aluminum scandium targets prepared in Examples 1-3 and Comparative Example 1

[0060] Example 1 Example 2 Example 3 Comparative Example 1 Relative density (%) 99.6 99.3 98.9 87.4 Oxygen content (ppm) 61 84 143 1072

[0061] As shown in Table 1, the relative density of the aluminum scandium target blanks prepared in Examples 1 to 3 of the present invention is 98.9% to 99.6%, which is higher than that of the aluminum scandium target blanks prepared by ordinary methods. This indicates that the present invention effectively refines the grains, reduces defects such as shrinkage cavities and porosity, and improves density through rapid filling and high-pressure solidification.

[0062] Figure 2 The images show SEM images (a) of the secondary precipitates in the aluminum-scandium alloy target billet in Example 1 and (b) of the fracture morphology after tensile testing. Figure 2As shown in a), this invention can make the secondary precipitates (the secondary precipitates after EDS scanning are Al3Sc phases) appear spherical and granular, and significantly reduce the volume ratio and agglomeration ratio of the precipitates. The fracture morphology after tensile testing also clearly shows that the fracture mode of the target blank obtained using the method described in this invention changes from brittle fracture to ductile fracture. Figure 2 In section b), obvious dimples can be observed. The presence of dimples proves that the material changes from brittle fracture to ductile fracture when stretched, confirming that the present invention effectively enhances the mechanical properties of the material and improves its resistance to deformation and reprocessing performance.

[0063] Figure 3 The image shows a comparison of SEM images of the aluminum-scandium alloy after casting (a) and die casting (b) in Example 2. As can be seen from the images, the secondary precipitates in the aluminum target scandium billet prepared by this invention exhibit a uniform and finely dispersed morphology, achieving the goal of uniform composition and reduced segregation.

[0064] Figure 4 SEM images (a) of the secondary precipitates and the fracture morphology after tensile testing of the aluminum-scandium alloy target billet in Comparative Example 1 (b). Figure 4 As shown in section a), the secondary precipitate Al3Sc in Comparative Example 1 exhibits dendritic morphologies such as squares or polygons. The Al3Sc phase is a brittle phase with a large volume fraction and significant agglomeration, resulting in uneven compositional distribution in the target blank. (Observation of fracture morphology...) Figure 2 As shown in b)), a significant amount of cubic precipitates are present on both sides of the crack propagation, which is a typical characteristic of brittle intergranular fracture. Through comparison... Figure 2 and Figure 4 It can be seen that under ordinary casting, the secondary precipitates are coarse, while after rapid filling and high-pressure die casting, the secondary precipitates are significantly improved, thereby improving the mechanical properties of the material.

[0065] Figure 5 The stress-strain curves for Comparative Example 1 and Example 1 are shown. From... Figure 5 As can be seen, the yield strength and elongation of Example 1 are significantly better than those of Comparative Example 1. This is because the present invention reduces the precipitation of the secondary brittle phase Al3Sc and weakens the agglomeration behavior of the precipitated phase, allowing Sc to dissolve into the matrix, achieving uniform composition and microstructure, and improving the plasticity of the aluminum-scandium alloy target billet. The fine and dispersed Al3Sc phase is a reinforcing phase, coherent with the Al matrix phase, acting as a pinning agent and increasing the strength of the aluminum-scandium target billet. This improves the mechanical properties of the aluminum-scandium target billet and significantly reduces deformation and cracking behavior in the preparation of large-size aluminum-scandium targets. It provides a solution for preparing 12-inch high-Sc-content aluminum-scandium alloy target billets.

[0066] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing an aluminum-scandium alloy target blank, characterized in that, The specific steps are as follows: Based on the elemental composition of the aluminum-scandium alloy target billet, the raw materials are melted to obtain the alloy melt; The alloy melt is pressed into a mold for rapid filling; the rapid filling speed is 3~5m / s, and the rapid filling time is 0.3~0.8s; After the rapid filling is completed, pressure is held, and the alloy melt in the mold solidifies rapidly to obtain the aluminum-scandium alloy target billet; the pressure held is 60~120MPa; The pressure holding time is 8~20s; The scandium content in the aluminum-scandium alloy target billet is 2-70 wt%, and the aluminum content is 30-98 wt%.

2. The preparation method according to claim 1, characterized in that, The raw materials used in the preparation include an aluminum-scandium master alloy, or pure aluminum and high-purity scandium, or an aluminum-scandium master alloy and pure aluminum.

3. The preparation method according to claim 1 or 2, characterized in that, The melting temperature is 655~1600℃.

4. The preparation method according to claim 1, characterized in that, The melting is carried out under vacuum or inert gas protection.

5. The preparation method according to claim 1 or 4, characterized in that, A salt covering agent is added during the smelting process, and the mass ratio of the salt covering agent to the raw materials is 1:20~500.

6. The preparation method according to claim 1, characterized in that, Before pressing the alloy melt into the mold, the mold is preheated. The preheating temperature is 80~300℃, and the preheating time is 10~60min.

7. The preparation method according to claim 6, characterized in that, Before preheating the mold, a release agent is sprayed onto the inner surface of the mold.

8. The aluminum-scandium alloy target blank prepared by the preparation method according to any one of claims 1 to 7, characterized in that, The aluminum-scandium alloy target blank has a relative density of 95.5-99.9% and an oxygen content of 60-300 ppm.

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