High-hardness aluminum alloy and preparation method and application thereof

Abstract

The invention relates to the technical field of aluminum alloy materials, and discloses a high-hardness aluminum alloy and a preparation method and application thereof.The high-hardness aluminum alloy comprises, by mass, 4.0-4.9% of Mg, 0.40-1.0% of Mn, smaller than or equal to 0.5% of Si, smaller than or equal to 0.5% of Pb, smaller than or equal to 0.5% of Sn, smaller than or equal to 0.5% of Ni, smaller than or equal to 0.5% of Fe, smaller than or equal to 0.1% of Cu, smaller than or equal to 0.25% of Cr, smaller than or equal to 0.25% of Zn, smaller than or equal to 0.15% of Ti, smaller than or equal to 0.25% of TiB2 and the balance aluminum. The alloy structure is a double-peak structure, large and small crystal grains are distributed in a staggered mode, the strength and plasticity of an aluminum alloy base material are effectively improved, and the follow-up machining performance is improved; the technical problem that when an existing 5XXX series aluminum alloy is used for preparing the thin knife rest of the scribing machine, notches are prone to being damaged is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of aluminum alloy materials, and in particular to a high-hardness aluminum alloy and a preparation method and application thereof. Background Art

[0002] The dicing machine is a precision machining equipment, which is widely used in the fields of semiconductors, electronics, optics, etc., and is used to cut various hard and brittle materials, such as silicon wafers, semiconductor packaging substrates, ceramics, glass, etc. In particular, the dicing machine is an important equipment in the semiconductor packaging link. At present, the domestic wafer dicing machine market is dominated by overseas companies such as Japan's DISCO and Jingdong Precision. The dicing machine blade is a tool used on the dicing machine, also known as a dicing knife or a grinding wheel. Among them, the tool commonly used for grooving or cutting is a thin diamond grinding wheel. The grinding wheel is divided into two types: "soft knife" and "hard knife"; generally speaking, a circular thin grinding wheel is called a soft knife, and a grinding wheel that combines a grinding wheel with an aluminum alloy tool holder (hereinafter referred to as: a hard knife tool holder) is called a hard knife.

[0003] The tool holder of the hard knife is made of aluminum alloy and can be directly installed on the cutting equipment when in use; however, at present, no domestic manufacturer can produce an aluminum alloy tool holder that can meet the application requirements, such as Figure 1 As shown, the main reason why domestic aluminum materials do not meet the standards is that the edge of the tool holder is prone to chipping and damage during high-speed operation, and the material falling from the tool holder will scratch the material and cause waste during the wafer cutting process.

[0004] The Chinese invention patent with publication number CN115323228A discloses a method for manufacturing a new aluminum alloy for a dicing blade aluminum disc, which provides an aluminum alloy material and a melting and casting method thereof, claiming that the prepared aluminum alloy has high strength, and the aluminum matrix thinned by alkali immersion has pits, so that the outer circle tip surface of the tool holder does not form a bulge, which is suitable for dicing blade aluminum discs, simple to operate, and low in cost. However, the above technology still has the following problems:

[0005] The casting obtained by using the common aluminum alloy composition and the conventional casting method in the prior art is used to prepare the thin blade holder of the dicing machine, such as Figure 2 As shown, since the thinnest part of the outer circle tip of the tool holder is only 1-2um, the existing aluminum alloy cannot meet the application requirements. During use, gaps will still appear at the outer circle tip of the tool holder, resulting in burrs, scratches and other problems on the edge of the product. Summary of the invention

[0006] The present invention aims to provide a high-hardness aluminum alloy and a preparation method and application thereof, so as to solve the technical problem that the existing aluminum alloy is prone to notch damage when used to prepare a thin blade holder of a dicing machine.

[0007] In order to achieve the above object, the present invention adopts the following technical scheme:

[0008] A high-hardness aluminum alloy comprises 4.0-4.9% Mg, 0.40-1.0% Mn, ≤0.5% Si, ≤0.5% Pb, ≤0.5% Sn, ≤0.5% Ni, ≤0.5% Fe, ≤0.1% Cu, ≤0.25% Cr, ≤0.25% Zn, ≤0.15% Ti, ≤0.25% TiB2, and the remainder is aluminum.

[0009] Invention concept:

[0010] At present, the reason why domestic aluminum alloy thin tool holders are difficult to meet application requirements is that there are many technical difficulties, including basic material research and development, processing technology, heat treatment technology, material cost and processing cost, etc.; and basic material research and development is the foundation of subsequent products, and the most important part is the relationship between alloy composition, microstructure and performance. The existing aluminum alloy can meet the application requirements of the dicing machine in terms of tensile strength, yield strength, hardness and other mechanical properties. The main problem at present is that the alloy structure is not good, which is not convenient for subsequent processing, especially for the thin tool holder of the dicing machine. The tip of the outer circle of the tool holder is small in size and high in precision. Even if it is manufactured by high-precision processing methods, the final performance still cannot meet the requirements. For example: after a period of use, a gap appears at the thinnest part of the outer circle of the tool holder, and the fallen material scratches the product. According to statistics, the scrap rate is as high as 50%.

[0011] Therefore, based on the above problems and the actual processing and application needs of customers, the inventors have conducted a lot of research on optimizing alloy composition and reducing processing technology costs, and finally obtained an aluminum alloy with a bimodal structure, in which there are both fine grains generated during melting and casting and early processing, and relatively large grains that grow or deform under the action of heat and force. These grains are staggered with the slender and large grains, and are numerous and equiaxed. Due to the presence of such fine equiaxed crystals and slender grains, the strength and plasticity of the material are improved, which will be beneficial to the subsequent processing and forming of the basic material, and ensure the processing performance of the material; and the thin tool holder prepared by the material of this application has no defects during the high-speed operation of the dicing machine, which meets the requirements of aluminum alloy materials for tool holders; and compared with the existing processing methods, the material cost of this application is significantly reduced, and it has excellent market potential.

[0012] Beneficial effects:

[0013] 1. Improve strength: TiB2, as a ceramic particle phase, has the characteristics of high hardness and high strength. When it is added to aluminum alloy, it can serve as the core of heterogeneous nucleation, increase nucleation sites during the solidification process of the alloy, thereby refining the grains and increasing the strength of the material.

[0014] 2. Enhanced corrosion resistance: The addition of TiB2 changes the microstructure and chemical properties of the aluminum alloy surface. It is evenly distributed in the aluminum alloy matrix and can fill some microscopic pores or defects that are prone to become corrosion channels, making it more difficult for corrosive media to invade the interior of the material; at the same time, it can also improve the density and stability of the oxide film formed on the surface of the aluminum alloy, making the oxide film more complete and dense, thereby enhancing the material's resistance to corrosive environments and improving corrosion resistance.

[0015] 3. Pinning dislocation effect: There is a certain interface bonding between TiB2 particles and the aluminum alloy matrix. When the dislocation line moves near these particles, it will be hindered by the particles, just like being "pinned" and difficult to continue sliding. Therefore, a higher external force is required to make the dislocation continue to move, which also plays a positive role in improving the strength of the material.

[0016] 4. By adding Pb (lead) and Sn (tin) to the aluminum alloy, the grains can be further refined, dislocations can be hindered, and the processing and cutting performance of the material can be improved; by adding Ni (nickel), the high temperature resistance and wear resistance of the material can be improved, wherein the Al3Ni phase generated by the reaction of Ni and Al is beneficial to improving the thermal stability of the material; in addition, the aluminum alloy in this application is used to manufacture a thin tool holder, and the Cu content is reduced, so that it can meet the requirements of improving the corrosion resistance of the material and improving the drawing processing performance of the material, and avoiding the aggravation of the alloy's thermal cracking tendency and the induction of cracks due to the high Cu content. Finally, by controlling the contents of Sn, Pb, and Ni, this application can also improve the surface finish of the material and avoid problems such as sticking of the tool.

[0017] In summary, this technology can be used to prepare thin blade holders for dicing machines through the interaction of the above-mentioned component ratio combinations, and is especially suitable for thin blade holder products in which the thinnest part of the outer circle tip of the blade holder is only 1-2um. It can ensure the strength and corrosion resistance of the final blade holder and other performances. The use of this blade holder can reduce the problems of burrs and scratches on the edges of the product. According to experiments, the scrap rate of processed products has been reduced from more than 50% to 10-20%.

[0018] Preferably, it includes 4.5% Mg, 0.5% Mn, 0.48% Si, 0.35% Pb, 0.42% Sn, 0.17% Ni, 0.10% Fe, 0.05% Cu, 0.20% Cr, 0.11% Zn, 0.11% Ti, 0.25% TiB2, and the rest is aluminum.

[0019] The present invention also provides a method for preparing a high-hardness aluminum alloy, comprising the following steps:

[0020] S1, melting and casting: mixing and melting the raw materials to obtain an ingot;

[0021] S2, extrusion: extruding the ingot formed in step 1;

[0022] S3, annealing: annealing the material after extrusion in step 2;

[0023] S4. Drawing: If it is a forward extruded bar, the total drawing deformation is greater than 15%; if it is a reverse extruded bar, the total drawing deformation should be greater than 10%.

[0024] Preferably, the drawing process is carried out in multiple times, and intermediate annealing is performed before each drawing, with an annealing temperature of 350° C., keeping the temperature for 30 minutes, and air cooling.

[0025] Preferably, in the melting and casting process, the aluminum material is melted and cast by DC casting, and when the TiB2 content is below 0.15%, ordinary mechanical stirring is adopted, and when the TiB2 content is above 0.15%, ordinary mechanical stirring + ultrasonic / electromagnetic stirring is adopted.

[0026] Preferably, in the extrusion process, the ingot is heated to 450-500°C in a heating furnace, the extrusion barrel temperature is 400-500°C, the extrusion speed is 1-1.5 mm / s, and the extrusion is forward / reverse.

[0027] Preferably, in the annealing process, the annealing temperature is 380° C., the temperature is kept for 1-1.5 hours, and the annealing is air-cooled.

[0028] Technical principles and beneficial effects:

[0029] In order to optimize the organizational structure of aluminum alloys and improve processing performance and application performance, in addition to improving the composition ratio of the alloy, its production process is also crucial. The prior art (CN115323228A) cited in the background technology of this application mainly adopts ordinary casting technology and homogenizes the cast rods obtained by casting, aiming to improve the crystal structure inside the cast rods, eliminate casting stress, reduce component segregation, and thus improve the metallurgical quality and subsequent processing performance of the cast rods; however, the homogenization treatment generally has a high processing temperature and a long insulation time, which prolongs the production process.

[0030] In addition, rapid solidification technology can also be used to improve the organizational structure of aluminum alloys, such as powder metallurgy, 3D printing, and belt casting. By making the aluminum alloy solidify quickly in a short time, the size and shape of the grains can be controlled, so that the alloy elements are more evenly distributed in the matrix, which is conducive to the formation of an ideal organizational structure. However, rapid solidification technology has very high requirements on equipment processing and control parameters. For example, the casting cost is more than 100,000 yuan / ton, so its production cost is very high. For the production of domestic aluminum alloys, if the cost cannot be effectively controlled, even if the material performance is improved, it will be difficult to obtain high competitiveness in the market.

[0031] The present invention optimizes the alloy composition and finds that a uniform internal crystalline structure can be obtained without homogenizing the cast rod. Therefore, the homogenization process can be omitted, that is, the production process of the present invention is shorter than that of the prior art; and the production cost is significantly reduced compared to the rapid solidification technology.

[0032] 1. Melting and casting process: When DC casting is used to melt aluminum materials, the aluminum alloy liquid can be solidified in a specific mold to provide an initial ingot for subsequent processing. Different stirring methods are used for different TiB2 contents. When the TiB2 content is low (below 0.15%), ordinary mechanical stirring can make the TiB2 particles initially evenly distributed in the aluminum alloy melt; when the TiB2 content is above 0.15%, ordinary mechanical stirring is combined with ultrasonic / electromagnetic stirring. Ultrasonic stirring uses the cavitation effect of ultrasonic waves to produce tiny bubbles in the liquid. The strong impact force generated when the bubbles burst can better disperse the TiB2 particles. Electromagnetic stirring drives the melt to flow through electromagnetic force, further enhancing the stirring effect, so that the TiB2 particles are evenly dispersed in the aluminum alloy melt. This melting and casting process can reasonably select the stirring method according to the TiB2 content to ensure the uniform distribution of TiB2 particles in the aluminum alloy, which is conducive to the subsequent formation of a uniform structure.

[0033] 2. Extrusion process: The ingot is heated at 450-500℃, and the extrusion barrel temperature is 400-500℃. This temperature range can keep the aluminum alloy in a good hot working state; at this temperature, the plasticity of the aluminum alloy increases, and the atomic diffusion capacity is enhanced, which is conducive to the deformation of the material. The extrusion speed is set to 1-1.5mm / s, and the forward / reverse extrusion method is adopted. During the extrusion process, due to the constraints of the mold and the action of external forces, the grains inside the aluminum alloy will be deformed; large grains will be elongated in the extrusion direction, while small grains will rotate and deform under the action of stress. At the same time, due to the uniform distribution of TiB2 particles in the previous melting and casting process and the small grains formed by heterogeneous nucleation, these small grains will hinder the excessive deformation of large grains during the extrusion process, so that the difference between large grains and small grains can be maintained, which is conducive to the formation of bimodal structure.

[0034] Selecting the above heating temperature and extrusion speed can ensure that the aluminum alloy material is smoothly extruded and deformed, and the material will not crack due to too low temperature, and the surface quality will not decrease due to too fast speed; and the forward or reverse extrusion method can make the material subject to stress in different directions, which is more conducive to grain refinement and the formation of complex organizational morphology, has a positive effect on the formation of bimodal organization, and can improve the isotropy of the material.

[0035] 3. Annealing process: The annealing temperature is set at 380℃, kept at this temperature for 1-1.5h, and air-cooled. During this annealing process, the residual stress inside the aluminum alloy is released; due to the certain work hardening and residual stress generated inside the material during the extrusion process, annealing can rearrange and annihilate dislocations and reduce the internal stress of the material. In particular, for the bimodal structure, the grains will undergo a certain degree of recrystallization during the annealing process, the small grains will grow slightly, and the large grains will also adjust the internal structure, but due to the organizational morphology formed by the previous extrusion and the pinning effect of the TiB2 particles, the basic morphology of the bimodal structure is maintained, and the performance of the material is optimized, making its comprehensive performance better, and avoiding the problem of material embrittlement caused by work hardening.

[0036] 4. Drawing process: For forward extruded bars, the total drawing deformation is greater than 15%, which is completed in multiple times, and intermediate annealing is performed before each drawing; during the drawing process, the material is subjected to axial tension again, which further refines and deforms the grains; since the previous bimodal structure has been formed, the small grains will further hinder the deformation of the large grains during the drawing process, and will also deform themselves. The intermediate annealing process can eliminate the work hardening caused by each drawing, so that the material can continue to be drawn next time. For reverse extruded bars, the total drawing deformation is greater than 10%, which is also completed in multiple times, and the intermediate annealing conditions are the same; in this process, the deformation of the material in different directions further adjusts the morphology of the bimodal structure, making the staggered distribution of large and small grains more compact and reasonable.

[0037] In summary, through the synergistic effect of the above series of processes, a bimodal structure is finally formed, which includes fine grains generated during melting and early processing, and relatively large grains formed by growth or deformation under the action of heat and force. In the end, the material hardness reached above 113HV, which is more than 10HV higher than the hardness of ordinary domestic 5XXX aluminum alloy materials; and through EBSD testing, it was found that there were elongated grains with a size of 400um, but there were also a large number of grains below 10um, which were interlaced with slender and large grains, and were numerous and equiaxed; in particular, due to the existence of such fine equiaxed crystals, the strength and performance of the material are improved, and the small grains wrapped around the large grains play a role in preventing the large grains from falling.

[0038] The present application realizes a bimodal structure by matching component design with a dedicated process. Usually, the bimodal structure of aluminum alloys mostly adopts rapid solidification technology, such as powder metallurgy, 3D printing, and belt casting, etc., and the casting cost is more than 100,000 yuan / ton. The present application significantly reduces the material cost compared with traditional processing methods by adding nano-medium and micro-alloy elements and matching a dedicated process.

[0039] An application of a high-hardness aluminum alloy is used in a hard knife holder of a dicing machine. When used in conjunction with a hard knife, the alloy can cut any hard and brittle material such as silicon wafers, semiconductor packaging substrates, ceramics, and glass without causing damage to the holder due to a notch.

[0040] Beneficial effect: The tool holder prepared by using the above materials and process has no defects during high-speed operation, meeting the requirements of aluminum alloy materials for tool holders. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 A schematic diagram of a notch appearing at the tip of an existing hard knife holder.

[0042] Figure 2 It is a cross-sectional view of the thin blade holder of the present invention.

[0043] Figure 3 This is the EBSD diagram of the alloy in Example 1 of the present invention.

[0044] Figure 4 This is the EBSD diagram of the alloy in Example 2 of the present invention.

[0045] Figure 5 This is the OM diagram of the alloy in Example 3 of the present invention.

[0046] Figure 6 This is the OM diagram of the alloy in Comparative Example 1 of the present invention.

[0047] Figure 7 This is the OM diagram of the alloy in Comparative Example 3 of the present invention.

[0048] Figure 8 This is the SEM image of the alloy in Example 4 of the present invention.

[0049] Fig. 9 This is the SEM image of the alloy in Comparative Example 4 of the present invention. DETAILED DESCRIPTION

[0050] The following is further described in detail through specific implementation methods:

[0051] The present invention provides a high-hardness aluminum alloy and a preparation method thereof. By optimizing the composition of the aluminum alloy and combining it with a special process, a bimodal structure can be formed. The structure is a typical heterogeneous structure, in which fine equiaxed crystals play a role in improving strength / hardness, and elongated grains play a role in improving the plasticity of the material. It is a typical organizational structure with simultaneous improvement of strength and plasticity.

[0052] That is, the aluminum alloy substrate provided by the present invention can further improve the strength and plasticity of the material on the basis of meeting the mechanical properties required by the application requirements, which is beneficial to subsequent processing; and when the bimodal structure of the alloy is used to prepare a thin tool holder, due to the excellent characteristics of the organizational structure, it is not easy to have a notch at the tip of the outer circle of the tool holder; in addition, the bimodal structure of the aluminum alloy of the present invention is not obtained by adopting the existing rapid solidification technology, but by adopting the more economical DC casting and plastic forming technology, and its production cost is significantly reduced, which has excellent market potential.

[0053] A high-hardness aluminum alloy comprises 4.0-4.9% Mg, 0.40-1.0% Mn, ≤0.5% Si, ≤0.5% Pb, ≤0.5% Sn, ≤0.5% Ni, ≤0.5% Fe, ≤0.1% Cu, ≤0.25% Cr, ≤0.25% Zn, ≤0.15% Ti, ≤0.25% TiB2, and the remainder is aluminum.

[0054] The present invention also provides a method for preparing a high-hardness aluminum alloy, comprising the following steps:

[0055] (1) Casting: Aluminum is cast by DC casting. When the TiB2 content is below 0.15%, ordinary mechanical stirring is adopted. When the TiB2 content is above 0.15%, ordinary mechanical stirring + ultrasonic / electromagnetic stirring is adopted. TiB2 is added 15 minutes after refining. The present application preferably adopts ordinary mechanical stirring + ultrasonic stirring when the TiB2 content is above 0.15% to ensure uniform dispersion of TiB2 and avoid agglomeration.

[0056] (2) Extrusion: The ingot is heated to 450-500°C in a heating furnace, the extrusion barrel temperature is 400-500°C, the extrusion speed is 1-1.5 mm / s, and the extrusion is performed in forward / reverse direction. Specifically, after step 1, a cast rod is obtained by casting, and the cast rod is cut into ingots as required, and the ingot is extruded.

[0057] (3) Annealing: Anneal the material at 380°C, keep warm for 1-1.5 hours, and air cool.

[0058] (4) Drawing: If the bar is extruded in the forward direction, the total deformation of the drawing should be greater than 15%, which can be completed in 2-3 times. Before each drawing, intermediate annealing is performed at 350°C, heat preservation for 30 minutes, and air cooling. If the bar is extruded in the reverse direction, the total deformation of the drawing should be greater than 10%, which can be completed in 2-3 times. Before each drawing, intermediate annealing is performed at 350°C, heat preservation for 30 minutes, and air cooling.

[0059] The present invention also provides an application of high-hardness aluminum alloy, which is used in the hard knife holder of a dicing machine. It can be used in conjunction with the hard knife to cut any hard and brittle material such as silicon wafers, semiconductor packaging substrates, ceramics, and glass, and the knife holder will not be damaged by notches.

[0060] Specifically, the aluminum alloy components and weight percentages involved in the embodiments and comparative examples of the present invention are detailed in Table 1.

[0061] Table 1: Aluminum alloy mass composition table (mass percentage, wt.%)

[0062]

[0063]

[0064] Table 2: Drawing process and alloy structure of each embodiment and comparative example

[0065]

[0066] Among them, the requirements, test methods, inspection rules, etc. for aluminum alloy extruded bars involved in the above-mentioned embodiments and comparative examples of the present application are carried out in accordance with the national standard GB / T 3191-2010.

[0067] The mechanical properties that need to be met when the aluminum alloy is used in the hard blade holder of a dicing machine are: tensile strength ≥ 270 MPa, Vickers hardness > 78. The mechanical properties of the aluminum alloy components disclosed in Examples 1-3 of the present application can all meet the standards, and on this basis, since the alloy structure realizes a bimodal structure, the strength and plasticity of the aluminum alloy substrate are further improved, which is convenient for subsequent processing; and the large and small grains in the bimodal structure are staggered, which improves the stability of the alloy structure.

[0068] Specifically, according to Examples 1-3, it can be known that by adopting the alloy composition ratio and processing technology of the present invention, a bimodal organizational structure can be obtained, in which the size of fine equiaxed crystals is less than 10um, and they are evenly wrapped around the outside of large grains. This effectively solves the problem of using existing ordinary 5XXX aluminum alloy to prepare a thin blade holder for a dicing machine, especially when the tip of the outer circle of the blade holder is only 1-2um, and notches and scratches on the product occur during high-speed operation. This can be used in the cutting process of ultra-thin and ultra-small wafers, reducing the scrap rate of the product from the original 50% to 10-20%.

[0069] According to Comparative Examples 1-3, when no TiB2 is added or an excessive amount of TiB2 is added to the alloy composition, a bimodal organizational structure cannot be obtained. When the alloy in the comparative example is used to manufacture a thin tool holder, there will still be problems of grain falling off or failure to form at the tip of the tool holder, resulting in scratches on the product. The scrap rate is not improved compared with that of a tool holder made of ordinary 5XXX aluminum alloy, and cannot meet application requirements.

[0070] Further, the present invention takes the alloy composition in Example 1 in Table 1 as an example, and performs homogenization treatment on the cast rod, and the experimental conclusions are shown in Table 3 below:

[0071] Table 3: Test on whether cast rods are homogenized

[0072]

[0073] The second phases in Table 3 are mainly Mg2Si phase and Fe phase. The volume fraction of Mg2Si phase is usually the largest among all the second phases, which has a significant influence and can enhance the strength and hardness of aluminum alloy, so that 5083 aluminum alloy has good performance in structural applications; Fe phase is usually formed during the smelting and casting process of aluminum alloy, especially when the iron content in the alloy is high, these phases often present granular or flaky morphology.

[0074] According to Example 4 and Comparative Example 4, it can be seen that the proportion, length and width of the second phase of the cast rods subjected to homogenization treatment and those subjected to no homogenization treatment are not much different, that is, the present invention can achieve uniform distribution of the second phase without homogenization treatment of the cast rods. Therefore, the homogenization treatment step can be omitted to simplify the production process.

[0075] The above is only an embodiment of the present invention, and the common knowledge such as the known specific technical solutions and / or characteristics in the solution is not described in detail here. It should be pointed out that for those skilled in the art, without departing from the technical solution of the present invention, several modifications and improvements can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A high hardness aluminum alloy, characterized in that: The invention comprises 4.0-4.9% Mg, 0.40-1.0% Mn, ≤0.5% Si, ≤0.5% Pb, ≤0.5% Sn, ≤0.5% Ni, ≤0.5% Fe, ≤0.1% Cu, ≤0.25% Cr, ≤0.25% Zn, ≤0.15% Ti, ≤0.25% TiB2, and the rest is aluminum.

2. The high hardness aluminum alloy according to claim 1, characterized in that: It includes 4.5% Mg, 0.5% Mn, 0.48% Si, 0.35% Pb, 0.42% Sn, 0.17% Ni, 0.10% Fe, 0.05% Cu, 0.20% Cr, 0.11% Zn, 0.11% Ti, 0.25% TiB2, and the rest is aluminum.

3. A method for preparing a high-hardness aluminum alloy, for preparing the high-hardness aluminum alloy as claimed in claim 1 or 2, characterized in that: The following steps are included: S1. Melting and casting: Mix and melt the raw materials to obtain cast rods, which are sawn into ingots as needed; S2, extrusion: extruding the ingot formed in step 1; S3, annealing: annealing the material after extrusion in step 2; S4. Drawing: If it is a forward extruded bar, the total drawing deformation is greater than 15%; if it is a reverse extruded bar, the total drawing deformation should be greater than 10%.

4. The method for preparing a high hardness aluminum alloy according to claim 3, characterized in that: The drawing process is carried out in multiple steps, and intermediate annealing is performed before each drawing. The annealing temperature is 350°C, the temperature is kept for 30 minutes, and air cooling is performed.

5. The method for preparing a high hardness aluminum alloy according to claim 4, characterized in that: In the melting and casting process, the aluminum material is melted and cast by DC casting, and when the TiB2 content is below 0.15%, ordinary mechanical stirring is adopted, and when the TiB2 content is above 0.15%, ordinary mechanical stirring + ultrasonic / electromagnetic stirring is adopted.

6. The method for preparing a high hardness aluminum alloy according to claim 5, characterized in that: In the extrusion process, the ingot is heated to 450-500°C in a heating furnace, the extrusion barrel temperature is 400-500°C, the extrusion speed is 1-1.5mm / s, and the extrusion is forward / reverse.

7. The method for preparing a high hardness aluminum alloy according to claim 6, characterized in that: In the annealing process, the annealing temperature is 380°C, kept for 1-1.5 hours, and air-cooled.

8. An application of a high hardness aluminum alloy, characterized in that: Used in the hard knife holder of the dicing machine, it can work with the hard knife to cut any hard and brittle material such as silicon wafers, semiconductor packaging substrates, ceramics, and glass, and the knife holder will not be damaged by notches.

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