High-toughness aluminum alloy and preparation method and application thereof

Abstract

The invention relates to the technical field of spacers, and particularly discloses a high-toughness aluminum alloy and a preparation method and application thereof. The high-toughness aluminum alloy provided by the invention is composed of Si, Mn, Mg, Zr, Sr, Er, Fe, nano # imgabs 0 # and aluminum according to a specific proportion, pure aluminum, Al-Si alloy, Al-Mn alloy, Al-Zr alloy, Al-Er alloy, # imgabs 1 # alloy and Al-Sr alloy according to a specific proportion are molten in batches, then refining treatment is performed, and finally the high-toughness aluminum alloy is obtained. The prepared high-toughness aluminum alloy has high compressive strength and good flexibility, and can adapt to an existing vacuum die-casting process; in addition, the invention further provides a spacer frame prepared from the high-toughness aluminum alloy and a die-casting die, and the spacer frame also has excellent compressive strength and flexibility. Therefore, the prepared high-toughness aluminum alloy and the spacer frame are better in strength and flexibility, the actual application requirements can be better met, and the problems that an existing die-casting alloy is low in strength and poor in toughness are solved.

Description

Technical Field

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

[0002] As a key metal accessory of overhead transmission lines, power fittings are responsible for mechanical connection, fixation and protection, including various types of connection fittings, splicing fittings, etc. As a type of power fittings, the spacer frame needs to withstand tension and irregular force during use, so there are high requirements for its strength and toughness, and its quality stability will directly affect the safe operation of the power grid system.

[0003] In recent years, my country's power industry, especially the construction of ultra-high voltage lines, has developed rapidly. Transmission lines are characterized by long distances, large transmission volumes and complex environments, which puts higher requirements on the electrical, mechanical and durability performance of power fittings. In terms of production raw materials, ferroalloys and aluminum alloys are the main materials for power fittings, among which cast iron and cast aluminum alloys are widely used. However, cast iron fittings have problems such as large mass, serious hot-dip galvanizing pollution and large power loss, so aluminum alloy manufacturing of power fittings has attracted more and more attention. At present, cast aluminum alloys such as ZL101A and ZL102 are commonly used, and heat treatment is performed by adding alloy elements to improve their strength. However, aluminum fittings still have outstanding problems of low mechanical strength and poor toughness. For example, the tensile yield strength of ordinary aluminum alloys ZL102 and ZL101A is only about 140MPa, which is far lower than the strength requirements of the State Grid for forgeable cast iron fittings.

[0004] To significantly enhance the strength of forged and cast aluminum fittings, the current production process has gradually abandoned traditional gravity casting or low-pressure casting methods and instead adopted more advanced die-casting processes, especially vacuum die-casting technology, which is then matched with specific die-casting alloys to achieve better mechanical properties. However, the Al-Si-Cu series alloys widely used in traditional die-casting (such as YL112 and ADC12), although they can improve the yield strength of the material to a certain extent, have obvious limitations in their compositional characteristics. The relatively high Si content in this series of alloys causes eutectic Si to exist in the form of a brittle phase, which greatly reduces the toughness of the material; while the relatively high Cu content helps to improve the strength, but at the same time it will also lead to a decrease in the toughness and corrosion resistance of the material. In contrast, the Al-Si-Mg series alloys (such as YL104, ADC3, and A360) exhibit good impact resistance and fatigue resistance. However, such alloys usually require solution strengthening and aging treatment to further improve their mechanical properties. But due to the fact that die-cast parts are mostly thin-walled and complex-structured parts, during the solution heat treatment process, it is easy for the casting to undergo severe deformation due to the stress generated by temperature changes and microstructure transformation, making it difficult to ensure the dimensional accuracy and quality stability of the parts. In summary, the existing die-cast aluminum alloys all have deficiencies to varying degrees in terms of performance and are difficult to simultaneously meet the requirements of power fittings for high strength, high toughness, impact resistance, and other aspects. Summary of the Invention

[0005] In view of this, the purpose of this application is to provide a high-toughness aluminum alloy, its preparation method, and its application to solve the problems of low strength and poor toughness of existing die-casting alloys.

[0006] To achieve the above technical objectives, this application provides a high-toughness aluminum alloy, including the following components by mass percentage:

[0007] Si 4.5 - 6.0%, Mn 0.3 - 0.6%, Mg 0.15 - 0.35%, Zr 0.05 - 0.15%, Sr 0.02 - 0.04%, Er 0.05 - 0.2%, Fe ≤ 0.25%, nano-TiB 2 0.05 - 0.5%, impurities ≤ 0.20%, and the balance is aluminum.

[0008] Further, the particle size of nano-TiB 2 is less than 100 nm.

[0009] Further, the impurities include one or more of Zn, Ni, Pb, Sn, Ca, and V.

[0010] This application provides a preparation method for a high-toughness aluminum alloy, including the following steps:

[0011] Step S1: Mix pure aluminum, Al-Si alloy, Al-Mn alloy, Al-Zr alloy, and Al-Er alloy, melt them, and stir until homogeneous to obtain a first melt.

[0012] Step S2: Add pure magnesium to the first melt, melt it, and stir until homogeneous to obtain a second melt.

[0013] Step S3: Add Al-TiB 2 alloy to the second melt, melt it, and stir until homogeneous to obtain a third melt.

[0014] Step S4: Add Al-Sr alloy to the third melt, melt it, and stir until homogeneous to obtain a fourth melt.

[0015] Step S5: Refine the fourth melt by rotary nitrogen blowing operation to obtain a high-toughness aluminum alloy.

[0016] Further, the preparation method of the Al-TiB 2 alloy is as follows: Mix aluminum, K 2 TiF 6 , KBF 4 , and NaNO 3 , melt them, and stir until homogeneous. Then, perform casting and cooling operations in sequence to obtain the Al-TiB 2 alloy.

[0017] Further, the mass ratio of pure aluminum, K 2 TiF 6 , KBF 4 , and NaNO 3 is 27:1:2:0.02.

[0018] This application provides an application of a high-toughness aluminum alloy for preparing a spacer frame.

[0019] Further, the steps of preparing a spacer frame with the high-toughness aluminum alloy are as follows: Take the melt of the high-toughness aluminum alloy after melting and cast it into the injection chamber of a die-casting machine. Connect the injection end of the die-casting machine to the feed port of the die-casting mold. After setting the vacuum degree inside the die-casting mold to the preset pressure, start the casting operation, and cast the melt from the injection chamber of the die-casting machine into the inside of the die-casting mold. After the casting is completed, wait for the melt to cool and solidify to obtain the spacer frame.

[0020] Further, the parameter settings for the die-casting process are as follows: The preset pressure inside the die-casting mold is less than 10 kPa; the temperature of the melt during casting is 680 °C; the injection pressure of the die-casting machine is 40 MPa, and the injection speed is 5.0 m / s.

[0021] Further, the die-casting mold includes a frame body 1, a shunt component 2, and an overflow component 3. The frame body 1 is a rectangular pipe structure, and the middle of the rectangular pipe is hollow. During die-casting, the melt fills the rectangular pipe to form a spacer bar frame body structure; positioning holes 11 are provided at the corners of the rectangular pipe for forming a spacer bar frame body structure with positioning holes during die-casting; the shunt component 2 includes a charging port 21 and a plurality of shunt bridges 22. The shunt bridges 22 are hollow pipes, and one end of the shunt bridge 22 is communicated with one side of the pipe near the center of the frame body 1, and the other end converges above the center of the frame body 1 to form a charging port 21. The shunt bridge 22 forms a 60° angle with the frame body 1; during melt die-casting, the melt is injected from the charging port 21 and evenly dispersed to each part of the frame body 1 through the shunt bridge 22; the overflow component 3 includes an overflow groove 31, an overflow pipe 32, and a vacuum valve 33; the overflow groove 31 is communicated with the frame body 1 for receiving the melt overflowing from the frame body 1; the overflow pipe 32 is communicated with the frame body 1 for discharging the melt inside the frame body 1; the vacuum valve 33 is arranged on the overflow pipe 32 for controlling the opening and closing of the overflow pipe 32.

[0022] In summary, the present application provides a high-toughness aluminum alloy and a preparation method thereof. The high-toughness aluminum alloy is composed of Si, Mn, Mg, Zr, Sr, Er, Fe, nano and aluminum in specific proportions; during its preparation process, pure aluminum, Al-Si alloy, Al-Mn alloy, Al-Zr alloy, Al-Er alloy, alloy, and Al-Sr alloy are melted in batches, and then refined to finally obtain a high-toughness aluminum alloy. The high-toughness aluminum alloy prepared by the present application has both high compressive strength and flexibility; its melt also has good fluidity and is highly compatible with the existing vacuum die-casting process. In addition, the present application also provides a spacer bar frame prepared by using the above high-toughness aluminum alloy with a specific die-casting mold. The prepared spacer bar frame also has excellent compressive strength and flexibility.

[0023] Compared with the prior art, the high-toughness aluminum alloy and spacer bar frame prepared by the present application perform better in terms of strength and flexibility, and can better meet the current requirements of electric power fittings. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0025] Figure 1 The electron micrograph of the microstructure of the high-toughness aluminum alloy provided by the embodiment of the present application;

[0026] Figure 2 The structural schematic diagram of a die-casting mold provided by the embodiment of the present application;

[0027] Figure 3 The structural schematic diagram of a spacer bar frame provided by the embodiment of the present application;

[0028] Reference numerals: 1. Frame body; 11. Positioning hole; 2. Shunt assembly; 21. Feed port; 22. Shunt bridge; 3. Overflow assembly; 31. Overflow tank; 32. Overflow pipe; 33. Vacuum valve. Detailed implementation manners

[0029] Next, the technical solutions of the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the specification of the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope claimed by the present application.

[0030] In the description of the present application, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0031] Unless otherwise clearly defined and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific situations.

[0032] Among them, there is no special limitation on the sources of all raw materials of the present invention, and they can be purchased on the market or prepared according to the conventional methods well-known to those skilled in the art.

[0033] The embodiment of the present application provides a high-toughness aluminum alloy, including the following components in mass percentage:

[0034] Si 4.5~6.0%, Mn 0.3~0.6%, Mg 0.15~0.35%, Zr 0.05~0.15%, Sr 0.02~0.04%, Er 0.05~0.2%, Fe≤0.25%, nano-TiB 2 0.05~0.5%, impurities ≤0.20%, the balance is aluminum.

[0035] It should be noted that the present invention adjusts the types and proportions of the metal elements in the aluminum alloy and then adds nano-TiB 2 Al-TiB 2 Alloy, to obtain a high-toughness aluminum alloy with excellent mechanical properties. In the high-toughness aluminum alloy, the optimal Si content is controlled at 4.5-6.0%. Because a high content of Si will form a fine Si phase in the Al-Si alloy, thereby hindering the dislocation movement of the aluminum matrix, it has the effect of enhancing the tensile strength and yield strength of the material, but a high content of Si will cause the flexibility of the aluminum matrix to decrease. Therefore, when the Si content is higher than 6.0%, the strength of the material increases while the elongation or toughness decreases, which is not conducive to the preparation of high-toughness aluminum alloys. When the Si content is lower than 4.5%, the Si phase that enhances the strength of the material is relatively small, and the strength of the alloy is generally low. At this time, the flexibility is enhanced, but it is not conducive to the preparation of high-strength aluminum alloys.

[0036] TiB 2 The lattice constant of the particles is similar to that of the α-Al phase, and the lattice mismatch rate is less than 5%, so TiB 2 The particles can become heterogeneous cores of α-Al phase during solidification and crystallization, which can refine the primary α-Al of Al-Si alloy. 2 The number of heterogeneous cores in the same volume after the particles are formed increases significantly, and the α-Al phase is greatly refined, especially when the nano-TiB 2 When the particle addition amount is 0.05-0.5%, a good refining effect can be achieved, and the α-Al grains can be refined to 20-50μm, greatly improving the flexibility of the aluminum alloy.

[0037] The solubility of Er element in aluminum is very small. During the solidification process of the melt, it is easily discharged to the front of the solid phase and aggregated, causing the composition to be supercooled, which can refine the grains and assist in refining the α-Al phase and eutectic Si phase. However, due to the rapid cooling rate of the aluminum liquid during the die-casting process, excessive Er can easily lead to the segregation of metal elements and even the appearance of Er-rich intermetallic compounds. Therefore, the content of rare earth Er is controlled at 0.05-0.2%. The addition of Zr element to aluminum alloy mainly plays a role in assisting the refinement of the primary α-Al phase. Zr element easily reacts with Al to form Al 3 Zr, fine Al during solidification 3The Zr phase can also serve as a heterogeneous nucleus for the α-Al phase, achieving the effect of grain refinement by increasing the number of crystal nuclei. Trace Zr elements and rare earth Er elements cooperate with nano-TiB 2 to obtain an ultrafine grain structure with a particle size of 20 - 50 μm, comprehensively improving the mechanical properties of the aluminum alloy.

[0038] Fe can reduce the tendency of aluminum liquid to stick to the mold during die casting, but during solidification, Fe will react with Al and Si in the alloy to form needle-like FeAl 3 and Al-Fe-Si intermediate compounds, which are likely to cut the alloy matrix structure and reduce the mechanical properties of the material, especially reducing toughness. Therefore, one of the characteristics of the present invention is to strictly control the content of Fe in the aluminum alloy. By controlling Fe in the raw materials and using a melting crucible without Fe, the content of Fe in the aluminum alloy is not higher than 0.25%. However, reducing the Fe content is likely to exacerbate the tendency of sticking to the mold during die casting. To reduce the risk of sticking and corrosion, Mn with properties similar to Fe is added to reduce the sticking phenomenon. When the content of Mn is less than 0.3%, its effect on reducing sticking is limited, while when it is higher than 0.6%, the mechanical properties such as toughness of the aluminum alloy will decrease. Therefore, the addition amount of Mn is set to 0.3 - 0.6%. The Sr element is used to transform the lamellar eutectic Si phase into a rod-like or seaweed-like shape, and its addition amount is the same as that used in conventional Al-Si alloys. Other impurity elements such as zinc, nickel, lead, tin, calcium, vanadium, etc. are all impurities, and the impurity content should be strictly controlled not to exceed 0.20%, otherwise it will seriously reduce the mechanical properties of the aluminum alloy, especially the content of zinc should be controlled below 0.10%.

[0039] In some embodiments, the particle size of nano-TiB 2 is less than 100 nm.

[0040] In some embodiments, the impurities include one or more of Zn, Ni, Pb, Sn, Ca, and V.

[0041] The embodiments of the present application provide a method for preparing a high-toughness aluminum alloy, including the following steps:

[0042] Step S1: Mix pure aluminum, Al-Si alloy, Al-Mn alloy, Al-Zr alloy, and Al-Er alloy, and after melting, stir until homogeneous to obtain a first melt;

[0043] Step S2: Add pure magnesium to the first melt, and after melting, stir until homogeneous to obtain a second melt;

[0044] Step S3: Add Al-TiB 2 alloy to the second melt, and after melting, stir until homogeneous to obtain a third melt;

[0045] Step S4: Add Al-Sr alloy into the third melt, melt it, and stir until it becomes homogeneous to obtain the fourth melt.

[0046] Step S5: Refine the fourth melt by means of rotary nitrogen blowing operation to obtain high-toughness aluminum alloy.

[0047] It should be noted that the preparation method of the high-toughness aluminum alloy must strictly follow the melting steps provided by the present invention. Specifically, in steps S1 - 4 of the present invention, the melting temperature range is 720 - 740 °C; in the rotary nitrogen blowing refining stage of step S5, the melt temperature is between 700 - 720 °C, and the refining time is 10 - 15 minutes. Through these operations, high-quality melt can be obtained, and then the high-toughness aluminum alloy as shown in Figure 1 can be prepared.

[0048] In some embodiments, the preparation method of the Al-TiB 2 alloy is as follows: Mix aluminum, K 2 TiF 6 , KBF 4 , and NaNO 3 , melt them, and stir until homogeneous, and then successively carry out casting and cooling operations to obtain the Al-TiB 2 alloy.

[0049] Preferably, the mass ratio of pure aluminum, K 2 TiF 6 , KBF 4 , and NaNO 3 is 27:1:2:0.02.

[0050] Specifically, during the preparation of the Al-TiB 2 alloy, set the melting temperature to 800 - 820 °C, and mechanically stir the melt at a rate of 800 r / min for 10 - 30 minutes; in addition, the content of nanometer in the alloy prepared according to the above ratio is 11%. It should be further noted that when preparing the alloy, its melting temperature is lower than that of the traditional method (about 850 °C), because at a lower melting temperature, the growth rate is slower, and it is easier to obtain nanoscale .

[0051] An embodiment of the present application provides an application of the high-toughness aluminum alloy for preparing a spacer frame.

[0052] The steps for using high-toughness aluminum alloy to prepare a spacer bar frame are as follows: Take the molten melt of high-toughness aluminum alloy and pour it into the injection chamber of a die-casting machine. Connect the injection end of the die-casting machine to the feed inlet of the die-casting mold. After setting the vacuum degree inside the die-casting mold to the preset pressure, start the casting operation, and pour the melt from the injection chamber of the die-casting machine into the inside of the die-casting mold. After the casting is completed, wait for the melt to cool and solidify to obtain a spacer bar frame.

[0053] Preferably, the parameter settings for the die-casting process are as follows: The preset pressure inside the die-casting mold is less than 10 kPa; the temperature of the melt during casting is 680 °C; the injection pressure of the die-casting machine is 40 MPa, and the injection speed is 5.0 m / s.

[0054] Preferably, referring to Figure 2 , the die-casting mold includes a frame body 1, a shunt assembly 2, and an overflow assembly 3. The frame body 1 is a rectangular pipe structure, and the middle of the rectangular pipe is hollow. During die-casting, the melt fills the rectangular pipe to form the main structure of the spacer bar frame; positioning holes 11 are opened at the corners of the rectangular pipe for forming the main structure of the spacer bar frame with positioning holes during die-casting; the shunt assembly 2 includes a feed port 21 and a plurality of shunt bridges 22. The shunt bridges 22 are hollow pipes, and one end of the shunt bridge 22 is connected to one side of the pipe near the center of the frame body 1, and the other end converges above the center of the frame body 1 to form a feed port 21. The shunt bridge 22 forms a 60° angle with the frame body 1. During melt die-casting, the melt is injected from the feed port 21 and evenly dispersed to each part of the frame body 1 through the shunt bridge 22; the overflow assembly 3 includes an overflow groove 31, an overflow pipe 32, and a vacuum valve 33; the overflow groove 31 is connected to the frame body 1 for receiving the melt overflowing from the frame body 1; the overflow pipe 32 is connected to the frame body 1 for discharging the melt inside the frame body 1; the vacuum valve 33 is arranged on the overflow pipe 32 for controlling the opening and closing of the overflow pipe 32.

[0055] Specifically, the frame body 1 can be a frame structure of a regular quadrilateral or a regular hexagon, and the whole is made of H13 die steel; the cross-sectional area of the shunt bridge 22 accounts for 15-20% of the cross-sectional area of the feed port 21, and the thickness of the feed port 21 is 0.5 mm - 1 mm. It should be noted that in this invention, by using an existing die-casting machine and a vacuum die-casting system, the internal pressure of the die-casting mold is controlled below 10 kPa, and a high-toughness aluminum alloy with an elongation rate of 14% is prepared. This aluminum alloy has no porosity defects and does not require subsequent heat treatment. The shunt bridge 22 in this invention can also adopt a curved diversion structure to ensure that the melt can flow smoothly in the shunt assembly and the die-casting mold, and it is not easy to have the phenomenon of air absorption; combined with the vacuum die-casting method, the gas content of the casting is significantly reduced, and its toughness is greatly improved.

[0056] The applicant further provides the following specific embodiments for reference to describe the present invention. It should be noted that these embodiments are merely descriptive and do not limit the present invention in any way.

[0057] Embodiment 1

[0058] This embodiment provides a preparation method of a nano-refining agent, and the specific steps are as follows:

[0059] Mix pure aluminum, K 2 TiF 6 , KBF 4 and NaNO 3 in a mass ratio of 27:1:2:0.02, place them in a melting crucible without iron, melt at a temperature of 800 °C, and stir at a speed of 800 r / min for 30 min in the molten state. After stirring, cool to 750 °C and cast to obtain an Al-TiB 2 intermediate alloy containing nano-TiB 2 . In the Al-TiB 2 intermediate alloy, the particle size of TiB 2 is less than 100 nm, and the content of TiB 2 is 11%.

[0060] This embodiment provides a preparation method of a high-toughness aluminum alloy, including the following steps:

[0061] Step S1: Mix pure aluminum and intermediate alloys (Al-20%Si, Al-10%Mn, Al-5%Zr, Al-5%Er), place them in a melting crucible without iron, set the melting temperature of the melting crucible to 720 - 740 °C, melt at this temperature and stir at a speed of 800 r / min for 30 minutes until the metal in the crucible is in a homogeneous state to obtain a first melt.

[0062] Step S2: Raise the melting temperature to 750 °C, add pure magnesium to the first melt to obtain a second melt with an alloy composition of 94.55%Al - 4.5%Si - 0.6%Mn - 0.05%Er - 0.15%Mg - 0.15%Zr;

[0063] Step S3: Add an Al-11%TiB 2 intermediate alloy with a TiB 2 content of 11% to the second melt, melt and stir until homogeneous to obtain a third melt. At this time, the content of nano-TiB 2 particles in the third melt is 0.5%;

[0064] Step S4: Add Al-10%Sr to the third melt, melt it, and stir until it becomes homogeneous to obtain the fourth melt. At this time, the content of Sr in the fourth melt is 0.02%.

[0065] Step S5: Lower the melting temperature to 720 °C, and refine the fourth melt by means of rotary nitrogen blowing for 15 minutes to obtain a high-toughness aluminum alloy.

[0066] This embodiment provides a spacer frame, which is prepared by using the die-casting mold as shown in Figure 1 and includes the following steps:

[0067] Connect the feeding end of the die-casting machine to the feeding port 21 of the die-casting mold, close the vacuum valve 33, set the internal pressure of the die-casting mold below 10 kPa, set the injection pressure of the die-casting machine to 40 MPa, and the injection speed to 5.0 m / s. After the parameter setting is completed, pour the high-toughness aluminum alloy melt with a melt temperature of 680 °C into the pressure chamber of the die-casting machine, start the casting operation, and the melt enters from the feeding port 21 and flows along multiple runner bridges 22 to various parts of the frame body 1. After the casting is completed, wait for it to cool and solidify to obtain the spacer frame as shown in Figure 3

[0068] Example 2

[0069] The difference from Example 1 is that:

[0070] In the preparation method of the nano-refining agent, the melting temperature is 820 °C and the stirring time is 10 min.

[0071] In the preparation method of the high-toughness aluminum alloy, the alloy composition and proportion of the second melt are 93.6%Al - 5.5%Si - 0.45%Mn - 0.15%Er - 0.2%Mg - 0.1%Zr; the content of TiB 2 particles in the third melt is 0.35%; the content of Sr in the fourth melt is 0.03%.

[0072] In the preparation process of the spacer frame, the casting temperature is 670 °C; the injection pressure of the die-casting machine is 60 MPa, and the injection speed is 3.5 m / s.

[0073] Example 3

[0074] In the preparation method of the nano-refining agent, the melting temperature is 810 °C and the stirring time is 20 min.

[0075] In the preparation method of the high-toughness aluminum alloy, the alloy composition and proportion of the second melt are 93.1%Al - 6.0%Si - 0.3%Mn - 0.2%Er - 0.35%Mg - 0.05%Zr; the content of TiB 2The particle content is 0.05%; the Sr content in the fourth melt is 0.04%.

[0076] During the preparation of the spacer frame, the casting temperature is 660 °C; the injection pressure of the die-casting machine is 50 MPa, and the injection speed is 4.5 m / s.

[0077] The tensile strength of the spacer frame is 315.1 MPa, the yield strength is 168.5 Ma, and the elongation at break is 14.4%.

[0078] Comparative Example 1

[0079] This comparative example provides an Al-Si-Cu series die-casting aluminum alloy ADC12. For the detailed parameters, please refer to Table 1.

[0080] Comparative Example 2

[0081] This comparative example provides an Al-Si-Mg series AlSi10MgFe die-casting aluminum alloy. For the detailed parameters, please refer to Table 1.

[0082] Table 1. Composition parameter values of aluminum alloys

[0083]

[0084] The mechanical properties of the aluminum alloys prepared in the above examples and comparative examples were tested. The results are shown in Table 2.

[0085] Table 2. Mechanical property parameter values of aluminum alloys

[0086]

[0087] From the data in Tables 1-2, it can be seen that the mechanical properties of the aluminum alloys prepared in Examples 1-3 of the present invention are all superior to those of Comparative Examples 1-2. This is due to the synergistic effect of rare earth elements Er and Zr and nano-TiB 2 , which significantly enhances the flexibility of the aluminum alloy. In addition, in Table 1, the silicon content of Comparative Examples 1-2 is in the range of 9-11%, while the silicon content in Examples 1-3 is only 4-6%. Since silicon is a key factor in regulating the strength of aluminum alloys, the examples of the present application have achieved a small increase in strength under the condition of only using a small amount of silicon compared with the comparative examples. Thus, it can be seen that the high-toughness aluminum alloy provided by the present invention breaks through the traditional strength characteristic mode dominated by silicon, and is remarkable in improving the strength of aluminum alloys with low silicon content, and successfully prepares an aluminum alloy material with both high strength and high toughness.

[0088] The above are the preferred embodiments of the present application and are not intended to limit the present invention. Although the present application has been described in detail with reference to the examples, those skilled in the art can still modify the technical solutions described in the foregoing examples, or perform equivalent replacements for some of the technical features. However, any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application.

Claims

1. A high toughness aluminum alloy, characterized in that: The following components are included in mass percentage: Si 4.5~6.0%, Mn 0.3~0.6%, Mg 0.15~0.35%, Zr 0.05~0.15%, Sr 0.02~0.04%, Er 0.05~0.2%, Fe≤0.25%, nano-TiB2 0.05~0.5%, impurities ≤0.20%, and the balance is aluminum.

2. The high toughness aluminum alloy according to claim 1, characterized in that: The particle size of the nano-TiB2 is less than 100 nm.

3. The high toughness aluminum alloy according to claim 1, characterized in that: The impurities include one or more of Zn, Ni, Pb, Sn, Ca and V.

4. A method for preparing a high-toughness aluminum alloy according to any one of claims 1 to 3, characterized in that: The following steps are involved: Step S1, pure aluminum, Al-Si alloy, Al-Mn alloy, Al-Zr alloy, and Al-Er alloy are mixed, and stirred until homogeneous after melting to obtain a first melt; Step S2, adding pure magnesium to the first melt, stirring the melt until it is homogeneous, and obtaining a second melt; Step S3, adding Al-TiB2 alloy to the second melt, stirring until it is homogeneous after melting, to obtain a third melt; Step S4, adding Al-Sr alloy to the third melt, stirring until homogeneous after melting, to obtain a fourth melt; Step S5, refining the fourth melt by a rotary nitrogen blowing operation to obtain a high-toughness aluminum alloy.

5. The method for preparing a high-toughness aluminum alloy according to claim 4, characterized in that: The preparation method of the Al-TiB2 alloy is: aluminum, K2TiF6, KBF4 and NaNO3 are mixed, stirred until homogeneous after melting, and then casting and cooling operations are performed in sequence to obtain the Al-TiB2 alloy.

6. The method for preparing a high-toughness aluminum alloy according to claim 5, characterized in that: The mass ratio of the pure aluminum, K2TiF6, KBF4 and NaNO3 is 27:1:2:0.

02.

7. An application of the high-toughness aluminum alloy according to any one of claims 1 to 3 or the high-toughness aluminum alloy prepared by the preparation method according to any one of claims 4 to 6, characterized in that: Used to prepare spacer rod frames.

8. The use of the high toughness aluminum alloy according to claim 7, characterized in that: The steps for preparing the spacer frame using high-toughness aluminum alloy are as follows: The molten high-toughness aluminum alloy is cast into the pressure chamber of the die-casting machine, the injection end of the die-casting machine is connected to the feed port of the die-casting mold, the vacuum degree inside the die-casting mold is set to a preset pressure, and the casting operation is started to cast the melt from the pressure chamber of the die-casting machine into the inside of the die-casting mold. After the casting is completed, the melt is cooled and formed to obtain a spacer rod frame.

9. The use of the high toughness aluminum alloy according to claim 8, characterized in that: The parameters of the die-casting process are set as follows: the preset pressure inside the die-casting mold is less than 10 kPa; the temperature of the melt during casting is 680° C.; the injection pressure of the die-casting machine is 40 MPa, and the injection speed is 5.0 m / s.

10. The use of the high toughness aluminum alloy according to claim 8, characterized in that: The die-casting mold comprises a frame body (1), a flow diversion component (2), and an overflow component (3); The frame body (1) is a rectangular pipe structure, the middle of the rectangular pipe is hollow, and during die casting, the molten metal fills the rectangular pipe to form a spacer bar frame body structure; the corners of the rectangular pipe are provided with positioning holes (11), which are used to form a spacer bar frame body structure with positioning holes during die casting; The flow diversion component (2) comprises a material injection port (21) and a plurality of flow diversion bridges (22), wherein the flow diversion bridge (22) is a hollow pipe, and one end of the flow diversion bridge (22) is connected to one side of the pipe near the center of the frame body (1), and the other end is gathered above the center of the frame body (1) to form a material injection port (21), and the flow diversion bridge (22) forms an angle of 60° with the frame body (1); when melt die-casting is performed, the melt is injected from the material injection port (21) and evenly dispersed to various parts of the frame body (1) through the flow diversion bridge (22); The overflow assembly (3) comprises an overflow groove (31), an overflow pipe (32), and a vacuum valve (33); the overflow groove (31) is in communication with the frame body (1) and is used to receive the melt overflowing from the frame body (1); the overflow pipe (32) is in communication with the frame body (1) and is used to guide the melt inside the frame body (1); the vacuum valve (33) is arranged on the overflow pipe (32) and is used to control the opening and closing of the overflow pipe (32).

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