Aluminum alloy, preparation method of aluminum alloy, die casting, welding assembly and electronic equipment

Abstract

The invention provides an aluminum alloy, a preparation method of the aluminum alloy, a die casting, a welding assembly and electronic equipment. On the basis of the total weight of the aluminum alloy, the aluminum alloy comprises, by weight, 0.01%-15% of La, 0.01%-15% of Ce, 0.3%-3% of Fe, 0.3%-3.0% of Mn, 0.01%-0.5% of Zr, the sum of the content of La and the content of Ce is 3%-15%, the balance Al and inevitable impurities, and the content of any impurity element in the inevitable impurities is smaller than or equal to 0.2%.

Description

Technical Field

[0001] The present application relates to the field of aluminum alloys, and specifically relates to an aluminum alloy, a preparation method thereof, a die-cast part, a welding assembly and an electronic device. Background Art

[0002] Brazing is a welding method in which a filler metal with a melting point lower than that of the welded part and the welded part are simultaneously heated to the melting temperature of the filler metal, and then the liquid filler metal is used to fill the gaps of the solid workpiece to connect the metals. Die-cast aluminum alloys are widely used due to their high production efficiency, low cost, and the ability to form complex structures in one step. However, current die-cast aluminum alloys mostly contain Si elements. Aluminum alloys of the Al-Si system have a relatively low melting point. For example, the melting point of the commonly used Al-Si alloy of grade ADC12 is 516 °C, and the melting point of the Al-Si alloy of grade ADC10 is 538 °C. The temperature of high-temperature brazing is usually around 600 °C, which will cause the aluminum alloy to melt during the brazing process. Although Al-1.6Mn can be brazed at high temperature, the material softens severely during the high-temperature brazing process, and the strength after brazing is very low. Therefore, there is currently a lack of a die-cast aluminum alloy that can still have high strength after high-temperature brazing. Summary of the Invention

[0003] The present application provides an aluminum alloy, a preparation method thereof, a die-cast part, a welding assembly and an electronic device to increase the melting point of the aluminum alloy and the strength of the aluminum alloy after brazing.

[0004] In a first aspect, the present application provides an aluminum alloy. Based on the total weight of the aluminum alloy, the aluminum alloy includes the following elemental composition by weight percentage: La 0.01% - 15%, Ce 0.01% - 15%, Fe 0.3% - 3%, Mn 0.3% - 3.0%, Zr 0.01% - 0.5%. The sum of the contents of La and Ce is 3% - 15%. The balance includes Al and unavoidable impurities, and the content of any impurity element in the unavoidable impurities is less than 0.2%.

[0005] In the aluminum alloy of the present application, by adding La with a mass fraction of 0.01% - 15% and Ce with a mass fraction of 0.01% - 15%, an aluminum-lanthanum-cerium rare-earth alloy with a high eutectic point can be formed with Al, so that the formed aluminum alloy has a relatively high melting point. For example, the melting point of the aluminum alloy can be higher than 640 °C. The addition of Fe can form long strip-shaped secondary phases with Al to increase the yield strength of the aluminum alloy. The added iron can reduce the adhesion of the aluminum alloy to the steel mold during the die-casting process, reduce the phenomenon of sticking to the mold, and improve the demolding effect of the aluminum alloy, thereby ensuring the die-casting forming effect. The addition of Mn can, on the one hand, cooperate with Fe to further improve the demolding effect, and on the other hand, improve the spheroidization degree of the Fe-containing secondary phase and enhance the strengthening effect of the secondary phase of the aluminum alloy. The addition of Zr can form precipitation phases with Al, such as Al3 Zr plays a role in precipitation strengthening. Through the combined action of the above elements, the obtained aluminum alloy can have a high melting point, avoiding the melting of the aluminum alloy due to the high temperature of brazing. At the same time, the aluminum alloy can also have high strength after high-temperature brazing.

[0006] In an optional implementation manner, by weight percentage, in the aluminum alloy, the weight fraction of La can be 2% - 10%, such as 2% - 7%, and further such as 2.4% - 4.0%. In an optional implementation manner, by weight percentage, in the aluminum alloy, the weight fraction of Ce can be 2% - 10%, such as 5% - 8%, and further such as 5.2% - 7.2%. In an optional implementation manner, the sum of the contents of La and Ce is 8% - 11%, such as 9% - 10.5%.

[0007] In an optional implementation manner, by weight percentage, in the aluminum alloy, the weight fraction of Fe can be 0.5% - 2.5%, such as 1% - 1.5%, and further such as 1.1% - 1.3%.

[0008] In an optional implementation manner, by weight percentage, when the aluminum alloy does not contain Cr, the weight fraction of Mn can be 0.5% - 2%, such as 0.6% - 1.5%, and further such as 0.6% - 1%, and further such as 0.85% - 1%.

[0009] In an optional implementation manner, by weight percentage, in the aluminum alloy, the weight fraction of Zr can be 0.1% - 0.5%, such as 0.15% - 0.40%, and further such as 0.20% - 0.35%, and further such as 0.20% - 0.30%.

[0010] In an optional implementation manner, by weight percentage, the contents of the elements La, Ce, Fe, Mn, and Zr in the aluminum alloy are as follows: La 2% - 7%, Ce 5% - 8%, Fe 1.0% - 1.5%, Mn 0.6% - 1%, and Zr 0.2% - 0.5%. In an optional implementation manner, by weight percentage, the contents of the elements La, Ce, Fe, Mn, and Zr in the aluminum alloy are as follows: La 2% - 5%, Ce 5% - 7.5%, Fe 1.1% - 1.3%, Mn 0.8% - 1%, and Zr 0.2% - 0.3%. The aluminum alloy with this composition can have a higher melting point and can have a higher yield strength after high-temperature brazing.

[0011] In an alternative implementation, by weight percentage, the aluminum alloy further includes 0.01% - 0.5% of Cr, such as 0.15% - 0.5%, for example 0.15% - 0.4%, and for another example 0.15% - 0.25%. The addition of Cr plays a role in forming a Cr-containing second-phase reinforcing phase and refining the grains, thereby improving the strength of the aluminum alloy. In an alternative implementation, when the aluminum alloy contains Cr by weight percentage, the weight fraction of Mn can be 0.5% - 1.2%, such as 0.5% - 0.9%, and for example 0.5% - 0.6%.

[0012] In an alternative implementation, by weight percentage, in the aluminum alloy, the contents of the elements La, Ce, Fe, Mn, Zr, and Cr are as follows: La 2% - 7%, Ce 5% - 8%, Fe 1.0% - 1.5%, Mn 0.45% - 0.60%, Zr 0.2% - 0.5%, and Cr 0.1% - 0.4%. In an alternative implementation, by weight percentage, in the aluminum alloy, the contents of the elements La, Ce, Fe, Mn, Zr, and Cr are as follows: La 2% - 5%, Ce 5% - 7.5%, Fe 1.1% - 1.3%, Mn 0.5% - 0.6%, Zr 0.2% - 0.35%, and Cr 0.2% - 0.3%. The aluminum alloy with this composition can have a higher melting point and can have a higher yield strength after high-temperature brazing.

[0013] In an alternative implementation, by weight percentage, the aluminum alloy further includes at least one of the following elements: Sc 0.01% - 0.5%, V 0.01% - 0.5%, Mo 0.01% - 0.5%, Ti 0.01% - 0.5%, Mg 0.01 - 0.5%. The addition of the above elements can help improve the thermal conductivity, hardness, and other properties of the aluminum alloy.

[0014] In an alternative implementation, the melting point of the aluminum alloy ≥ 620 °C. In an alternative implementation, the thermal conductivity of the aluminum alloy ≥ 120 W / m·K. In an alternative implementation, the yield strength of the aluminum alloy after brazing at 590 - 630 °C ≥ 80 MPa.

[0015] In a second aspect, the present application provides a method for preparing an aluminum alloy, which includes: melting the master alloys of each element according to the composition of the aluminum alloy of the present application to obtain an alloy melt, and after refining, degassing, and slag removal of the alloy melt, performing die casting to obtain the aluminum alloy.

[0016] In a third aspect, the present application provides a die casting part, which is prepared by using the aluminum alloy of the present application.

[0017] Fourthly, the present application provides a welding assembly, including a metal matrix and the die-casting part of the present application, and the die-casting part is connected to the metal matrix by brazing.

[0018] Fifthly, the present application provides an electronic device, including a processing unit and a packaging component for packaging the processing unit, and at least part of the structural components in the packaging component are the die-casting parts of the present application.

[0019] For the technical effects that can be achieved in the second to fifth aspects above, reference can be made to the corresponding effect descriptions in the first aspect above, and details will not be repeated here.

[0020] Among them, for the data in each possible implementation manner of the present application, such as the weight percentages of La, Ce, Fe, Mn, and Zr, etc., during measurement, the values within the range of engineering measurement errors should be understood as being within the range defined by the present application. Description of the Drawings

[0021] Figure 1 It is a schematic structural diagram of a heat dissipation plate;

[0022] Figure 2 It is a microstructure diagram of an aluminum alloy in an embodiment;

[0023] Figure 3 It is an ultrasonic detection diagram of the welding surface of the die-casting part after brazing;

[0024] Figure 4 It is a DSC test curve diagram of the aluminum alloy in Example 1;

[0025] Figure 5 It is the stress and strain curves of the aluminum alloy in Example 1 after brazing;

[0026] Figure 6 It is a schematic diagram of the weld seam after brazing the aluminum alloy in Example 1 with other components;

[0027] Figure 7 It is the stress and strain curves at the weld seam of the aluminum alloy in Example 1;

[0028] Figure 8 It is a physical diagram of the pressure-resistant bursting after brazing a die-casting structural part and a plate in an embodiment. Detailed Embodiments

[0029] In order to make the objectives, technical solutions, and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings.

[0030] The terms used in the following embodiments are only for the purpose of describing specific embodiments and are not intended to limit this application. As used in the specification and appended claims of this application, the singular forms "a", "an", "the above", "the", and "this" are also intended to include expressions such as "one or more", unless the context clearly indicates otherwise. References to "one embodiment" or "some embodiments" etc. described in this specification mean that a specific feature, structure, or characteristic described in connection with the embodiment is included in one or more embodiments of this application. The terms "comprising", "including", "having" and their variants all mean "including but not limited to", unless otherwise specifically emphasized in other ways. In this application, unless otherwise specified, the percentage (%) or parts refer to the weight percentage or weight parts relative to the composition. In this application, unless otherwise stated, the various components or their preferred components involved can be combined with each other to form a new technical solution. In this application, unless otherwise specified, the numerical range "a~b" represents an abbreviated representation of any real number combination between a and b, where a and b are both real numbers.

[0031] Due to advantages such as high production efficiency, low cost, and the ability to form complex structures, aluminum alloys are widely used in communication equipment, automobiles, consumer electronics, etc. For example, aluminum alloys can be widely used in the casings of various electronic devices, and the electronic devices include, but are not limited to, communication equipment, such as large-scale multiple-input multiple-output systems, radio frequency remote units, active antenna processing units, etc. Of course, in addition to communication equipment, electronic devices can also include electronic computers, numerical control devices, programmed control devices, vehicle-mounted thermal cycle casings, in-vehicle computer cooling casings, etc., which will not be listed one by one here.

[0032] Exemplarily, an electronic device may include: a casing and a processing unit located inside the casing. The processing unit can be any unit with processing functions in the electronic device, such as a processor, a processing circuit, etc. A heat dissipation plate may be included in the components of the casing, and the processing unit may be disposed on the heat dissipation plate to cool the processing unit by using the heat dissipation plate. Figure 1 It is a schematic structural diagram of a heat dissipation plate. This heat dissipation plate can be used as a part of the casing of an electronic device. Refer to Figure 1 As shown, this heat dissipation plate may include a base and a cover plate. The structure of the cover plate is as shown in Figure (a) in Figure 1 and the structure of the base is as shown in Figure (b) in Figure 1 The structure after the base and the cover plate are hermetically connected is as shown in Figure 1As shown in Figure (c). A coolant flow channel is provided in the base to enable the flow of coolant. The cover plate is hermetically connected to the base to seal the coolant flow channel. The hermetic connection between the base and the cover plate can be achieved by brazing. Among them, the base 10 has a frame a1, a bottom plate a2, and an island structure a3 provided on the bottom plate a2. Part of the island structure a3 is connected to the frame a1, and the island structure a3 is provided in the space enclosed by the frame a1 and the bottom plate a2. Among them, the base can be prepared by die-casting aluminum alloy through die-casting process to save materials and reduce machining processes. The cover plate 20 is a brazing composite plate (as shown in Figure (a)), and the cover plate 20 is a flat plate structure with a certain thickness. When welding the base and the cover plate, the brazing filler metal can be placed on the surface of the cover plate 20, so that the surface of the cover plate 20 with the brazing filler metal contacts the base 10. Then, the brazing filler metal on the surface of the cover plate 20 contacts the frame a1 and the island structure a3 of the base 10 respectively. After high-temperature brazing, the cover plate 20 and the base 20 can be welded together through the island structure a3 and the frame a1, and the area between the cover plate 20 and the base 20 except the island structure a3 forms a cavity, which is used as a coolant flow channel. When the heat sink is used for heat dissipation, the refrigerant can be injected into the two coolant flow channels through the liquid injection pipe 30 provided on the cover plate 20, so that the refrigerant can evaporate, cool, and circulate in the cavity, thereby taking away heat and realizing the heat dissipation function. Of course, the cover plate 20 is not limited to a flat plate structure, and can also be other structures that can be hermetically connected to the base and form a space between the two. It should be understood that the structure of the die-cast part of the present application is not limited to Figure 1 shown, and can also be other shapes set according to factors such as actual application scenarios and usage purposes, which are not limited here.

[0033] Among them, when welding aluminum alloy die-castings, high-temperature brazing can be used for welding. This requires ensuring that the melting point of the aluminum alloy die-casting is higher than the temperature used in high-temperature brazing. If the melting point of the aluminum alloy casting is lower than the temperature used in high-temperature brazing, the aluminum alloy die-casting will melt during high-temperature brazing and the desired structure cannot be obtained. Usually, the temperature used in high-temperature brazing is about 600 °C, and the commonly used aluminum alloy die-castings are generally Al-Si series alloys. The melting point of Al-Si series alloys is relatively low, about 577 °C. Obviously, the melting point of Al-Si series alloys is lower than the temperature used in high-temperature brazing. Therefore, the aluminum alloy castings made of Al-Si series alloys cannot be applied to the field of high-temperature brazing.

[0034] In view of this, an embodiment of the present application provides an aluminum alloy. This aluminum alloy can be used in die-casting processes to form various complex die-castings. This aluminum alloy can have a high melting point, such as a melting point reaching 640 °C or higher. The die-castings formed using the aluminum alloy of the embodiment of the present application can withstand the high temperature of brazing without melting, and can also have a relatively high yield strength after high-temperature brazing, for example, the yield strength can reach above 120 MPa, so as to meet the requirements of high structural strength and high reliability. At the same time, the aluminum alloy of the embodiment of the present application will not react with the filler metal, affecting the appearance and mechanical properties of the aluminum alloy.

[0035] The aluminum alloy of the embodiment of the present application includes Al, alloying elements, and inevitable impurities. Among them, based on the total weight of the aluminum alloy, the alloying elements may include the following elements by weight percentage: La 0.01% - 15%, Ce 0.01% - 15%, Fe 0.3% - 3%, Mn 0.3% - 3.0%, Zr 0.01% - 0.5%, and the sum of the contents of La and Ce is 3% - 15%. When Si exists in the form of inevitable impurities, its content is less than or equal to 0.2%, preferably ≤0.1%. In addition, in the aluminum alloy of the embodiment of the present application, the content of any impurity element in the inevitable impurities is less than 0.2%. Among them, the total amount of inevitable impurities ≤0.4%.

[0036] Lanthanum La and cerium Ce

[0037] Regarding the added lanthanum and cerium: By adding lanthanum with a mass fraction of 0.01% - 15%, an aluminum-lanthanum alloy with a eutectic point temperature above 640 °C can be formed. By adding cerium with a mass fraction of 0.01% - 15%, an aluminum-cerium alloy with a eutectic point temperature above 640 °C can be formed, so that the aluminum alloy added with lanthanum and cerium has a relatively high melting point, and the melting point of this aluminum alloy can reach above 630 °C. When the temperature of high-temperature brazing is about 600 °C, the melting point of this aluminum alloy is higher than the temperature during high-temperature brazing, so this aluminum alloy will not melt during high-temperature brazing and can be applied to high-temperature brazing. And, the standard electrode potential of lanthanum is about -2.379 V, the standard electrode potential of cerium is about -2.336 V, while the standard electrode potential of aluminum is about -1.66 V. Obviously, the ability of lanthanum and cerium to lose electrons is higher than that of aluminum to lose electrons. Therefore, during corrosion, lanthanum and cerium are corroded first while aluminum is less likely to be corroded. Thus, the introduction of lanthanum and cerium plays a protective role for aluminum and improves the corrosion resistance of the aluminum alloy. In addition, during the cooling stage of the molten liquid during die-casting forming, the introduced lanthanum and cerium can form intermetallic compound second-phase particles with aluminum, such as Al 11 (La,Ce) 3, this intermetallic compound second-phase particle can be called an in-situ second-phase particle, and these intermetallic compound second-phase particles, as heterogeneous nuclei, can increase the number of nuclei in the aluminum alloy. During the growth of the nuclei, various nuclei collide with each other and inhibit the growth of grains, thus refining the grains. Since the intermetallic compound second-phase particles are only generated during the solidification and cooling stage of the die-casting molten liquid, before the solidification and cooling stage of the die-casting molten liquid, due to the absence of these intermetallic compound second-phase particles, the effect of refining grains by heterogeneous nuclei cannot be exerted. Therefore, the addition of lanthanum and cerium can, to a certain extent, improve the mechanical properties of the aluminum alloy after die-casting, but the improvement degree is limited.

[0038] Among them, the content of La in the embodiments of the present application is controlled to be 0.01% - 15%, further 2% - 10%, for example 2% - 7%, and for example 2.4% - 4.0%, and its effect of increasing the melting point of the aluminum alloy is more obvious. Calculated by weight percentage, the addition amount of La in the aluminum alloy can be, for example, 0.01%, 0.5%, 1%, 1.5%, 2%, 2.2%, 2.5%, 2.8%, 3%, 3.2%, 3.5%, 3.8%, 4%, 4.2%, 4.5%, 4.8%, 5%, 5.2%, 5.5%, 5.8%, 6%, 6.2%, 6.5%, 6.8%, 7%, 7.2%, 7.5%, 7.8%, 8%, 8.5%, 9%, 10%, 11%, 12%, 13%, 15% or any value between the above two values. The above-listed values are all for illustrative purposes. The lower limit value of the addition amount of La can be any of the above values or a value between the above two values; the lower limit value of the addition amount of La can be any of the above values or a value between the above two values.

[0039] When the content of La in the embodiments of the present application is controlled to be 0.01% - 15%, further 2% - 10%, for example 5% - 8%, and for example 5.2% - 8%, its effect of increasing the melting point of the aluminum alloy is more obvious. Calculated by weight percentage, the addition amount of Ce in the aluminum alloy can be, for example, 0.5%, 1%, 1.5%, 2%, 2.2%, 2.5%, 2.8%, 3%, 3.2%, 3.5%, 3.8%, 4%, 4.2%, 4.5%, 4.8%, 5%, 5.2%, 5.5%, 5.8%, 6%, 6.2%, 6.5%, 6.8%, 7%, 7.2%, 7.5%, 7.8%, 8%, 8.5%, 9%, 10%, 11%, 12%, 13%, 15% or any value between the above two values. The above-listed values are all for illustrative purposes. The lower limit value of the addition amount of Ce can be any of the above values or a value between the above two values; the lower limit value of the addition amount of Ce can be any of the above values or a value between the above two values.

[0040] Among them, by weight percentage, the total addition amount of La and Ce in the aluminum alloy can be 3% - 15%, such as 8% - 11%, and further such as 9% - 10.5%. Exemplarily, for example, 8%, 8.2%, 8.5%, 8.7%, 9%, 9.2%, 9.5%, 9.7%, 10%, 10.2%, 10.5%, 10.7%, 11%, 12%, 13%, or 15% or any value between the above two values. The values listed above are all for illustration. The lower limit value of the addition amount of La and Ce can be any of the above values, or a value between the above two values; the lower limit value of the addition amount of La and Ce can be any of the above values, or a value between the above two values.

[0041] Iron Fe:

[0042] For Fe: By adding iron with a mass fraction of 0.3% - 3%, during the solidification and cooling stage of the molten liquid in die-casting, iron can also form the second-phase particles of intermetallic compounds in the aluminum liquid, such as (La,Ce)Fe 2 Al 10 , and these second-phase particles of intermetallic compounds can also be called self-generated second-phase particles. During the die-casting process of the aluminum alloy, these second-phase particles of intermetallic compounds can also act as heterogeneous nuclei to refine the grain size. Also, because these second-phase particles of intermetallic compounds are generated during the solidification and cooling stage of the molten liquid in die-casting, to a certain extent, they can also improve the mechanical properties of the aluminum alloy, but the improvement degree is limited. Moreover, the added iron can reduce the adhesion of the aluminum alloy to the steel die during the die-casting process, reduce the sticking mold phenomenon, improve the demolding effect of the aluminum alloy, and thus improve the die-casting effect.

[0043] When the content of Fe is 0.3% - 3%, further when it is 0.5% - 2.5%, and further such as 1% - 1.5%, and further such as 1.1% - 1.3%, its effect of increasing the yield strength of the aluminum alloy is more obvious. By weight percentage, the addition amount of Fe in the aluminum alloy can be, for example, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, or 3% or any value between the above two values. The values listed above are all for illustration. The lower limit value of the addition amount of Fe can be any of the above values, or a value between the above two values; the lower limit value of the addition amount of Fe can be any of the above values, or a value between the above two values.

[0044] Manganese Mn:

[0045] For the added manganese: Adding manganese with a mass fraction of 0.3% to 3% has a solution strengthening effect on the one hand. Moreover, manganese can transform the flaky iron-containing intermetallic compound second-phase particles into fine spherical intermetallic compound second-phase particles, thereby improving the strengthening effect of the iron-containing intermetallic compound second-phase particles. Thus, under the action of manganese, the strengthening effect of iron on the mechanical properties of aluminum alloy can be increased. In addition, since the eutectic point temperature of aluminum and manganese is about 658 °C, while the freezing point temperature of aluminum is about 660 °C, the addition of manganese has little effect on the melting point of the aluminum alloy. Additionally, after manganese combines with iron, it can further reduce the tendency of the casting to stick to the steel die, thereby improving the die-casting forming effect.

[0046] The content of Mn can be 0.3% to 1.2%. When the alloying elements of the aluminum alloy do not contain Cr, when the content of Mn is in the range of 0.7% to 1.1%, for example, in the range of 0.7% to 1%, or for example, in the range of 0.85% to 1%, its effect of increasing the yield strength of the aluminum alloy is more obvious. Calculated by weight percentage, the addition amount of Mn in the aluminum alloy can be, for example, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, 0.55%, 0.6%, 0.65%, 0.7%, 0.75%, 0.8%, 0.85%, 0.9%, 0.95%, 1.0%, 1.05%, 1.1%, 1.15%, or 1.2% or any value between the above two values. The above-listed values are all for illustrative purposes. The lower limit value of the addition amount of Mn can be any of the above values or a value between the above two values; the lower limit value of the addition amount of Mn can be any of the above values or a value between the above two values.

[0047] Zirconium Zr:

[0048] For the added zirconium: By adding zirconium with a mass fraction of 0.01% to 0.5%, zirconium, as a heterogeneous crystal nucleus, can promote the formation of a large number of nano-precipitation phases, such as Al 3 Zr. During the die-casting forming process of the aluminum alloy, it plays a role in refining the grains, thereby further improving the mechanical properties of the aluminum alloy after die-casting forming and after high-temperature brazing. If the content of Zr is too low, the purpose of effectively refining the grains and improving the strength of the aluminum alloy cannot be achieved. If the content of Zr is too high, the further increase in strength is not obvious, and at the same time, the cost increases significantly.

[0049] Among them, when the content of Zr can be 0.01% - 0.5%, such as 0.1% - 0.5%, further 0.15% - 0.5%, for example 0.2% - 0.4%, and for example 0.2% - 0.35%, the effect of increasing the yield strength of the aluminum alloy is more obvious. Calculated by weight percentage, the addition amount of Zr in the aluminum alloy can be, for example, 0.01%, 0.02%, 0.03%, 0.05%, 0.07%, 0.08%, 0.1%, 0.12%, 0.15%, 0.18%, 0.2%, 0.22%, 0.25%, 0.28%, 0.3%, 0.33%, 0.35%, 0.38%, 0.4%, 0.42%, 0.45%, or 0.5% or any value between the above two values. The values listed above are all for illustrative purposes. The lower limit value of the addition amount of Zr can be any of the above values or a value between the above two values; the lower limit value of the addition amount of Zr can be any of the above values or a value between the above two values.

[0050] In summary, by adding specific contents of lanthanum, cerium, iron, manganese, and zirconium to aluminum, the effects of increasing the melting point and mechanical strengthening can be jointly exerted, so that the obtained aluminum alloy has a relatively high melting point, can be used for high-temperature brazing, and also has good mechanical properties, corrosion resistance, and die-casting forming effects.

[0051] In the aluminum alloy of some embodiments, based on the total mass of the aluminum alloy, the aluminum alloy includes the following elements by weight percentage: La 2% - 7%, Ce 5% - 8%, Fe 1.0% - 1.5%, Mn 0.7% - 1%, and Zr 0.2% - 0.5%; the sum of the contents of La and Ce is 5% - 15%, such as 8% - 11%. The aluminum alloy does not include Si or Si exists in the form of inevitable impurities, and the balance includes Al and inevitable impurities. The content of any impurity element in the inevitable impurities is less than 0.2%, and when Si exists in the form of inevitable impurities, the content is less than 0.2%, such as ≤0.1%.

[0052] Chromium Cr:

[0053] In the aluminum alloy of some embodiments, the alloying components may further include Cr. By weight percentage, the content of Cr may be, for example, 0.01% to 0.5%. The addition of Cr can form the AlCeCrMn phase with Al, Ce, and Mn, transform the intermetallic compound into denser second-phase particles with a higher sphericity, play a role in refining the grains, reducing internal defects, improving the strengthening effect, and further increasing the strength of the aluminum alloy. Among them, when the content of Cr can be 0.15% to 0.5%, further within 0.15% to 0.4%, and for example, within 0.2% to 0.4%, the effect of increasing the yield strength of the aluminum alloy is more obvious. By weight percentage, the addition amount of Cr in the aluminum alloy may be, for example, 0.01%, 0.02%, 0.05%, 0.07%, 0.1%, 0.12%, 0.15%, 0.18%, 0.2%, 0.22%, 0.25%, 0.28%, 0.3%, 0.32%, 0.35%, 0.37%, 0.4%, 0.42%, 0.45%, 0.48%, or 0.5% or any value between the above two values. The above-listed values are all for illustrative purposes. The lower limit value of the addition amount of Cr can be any of the above values or a value between the above two values; the lower limit value of the addition amount of Cr can be any of the above values or a value between the above two values.

[0054] Among them, when the aluminum alloy contains Cr, the addition amount of Mn in the aluminum alloy may be 0.3% to 0.7%, for example, 0.4% to 0.7%, for example, 0.45% to 0.7%, for example, 0.45% to 0.60%. Thus, the yield strength of the aluminum alloy can be further increased.

[0055] In the aluminum alloy of some embodiments, based on the total mass of the aluminum alloy, the aluminum alloy includes the following elemental composition by weight percentage: La 2% to 7%, Ce 5% to 8%, Fe 1.0% to 1.5%, Mn 0.45% to 0.6%, Zr 0.2% to 0.5%, and Cr 0.1% to 0.4%; the sum of the contents of La and Ce is 5% to 15%, such as 8% to 11%. The aluminum alloy does not include Si or Si exists in the form of inevitable impurities, and the balance includes Al and inevitable impurities. The content of any impurity element in the inevitable impurities is less than 0.2%, and when Mg exists in the form of inevitable impurities, the content ≤ 0.2%.

[0056] Figure 2 It is the microstructure diagram of an aluminum alloy of an embodiment. As Figure 2As shown in the figure, in the microstructure of the aluminum alloy according to the embodiment of the present application, the phases are evenly distributed, with small sizes, and the morphology of the grains approaches a spherical equiaxed structure. Thus, it can be shown that in the aluminum alloy of the present application, there are many second phases evenly embedded in the aluminum matrix. After high-temperature brazing, a large number of second phases can effectively inhibit grain growth and strengthen the aluminum alloy at the same time.

[0057] Figure 2 In the crystal phase structure shown, the descriptions of the grain morphologies of different phases and the compositions of the phase components are listed in Table 1.

[0058] Table 1

[0059]

[0060]

[0061] Combined with Figure 2 and Table 1, it can be seen that the elements interact with each other to form phase structures with different morphologies. Among them, Al3(La, Ce) is evenly distributed in dots, and Al3(La, Ce)+α-Al is distributed in a network structure between the grains of the spherical α-Al matrix. The second phases Al(La, Ce)FeMn and AlCeCrMn are evenly dispersed in blocks to help improve the strength of the aluminum alloy. At the same time, Zr exists in the form of Al 3 Zr precipitation phase, presenting a nano-spherical structure, which can refine the grains of each phase and improve the material strength by hindering the movement of dislocations through the precipitation phase. Through the above elements forming different second-phase / precipitation-phase grain refinement and hindering grain growth, they work together synergistically to keep the brazed material with high strength.

[0062] Among them, the melting point of the aluminum alloy containing the above components can be ≥600 °C, such as greater than or equal to 630 °C. In addition, the thermal conductivity of the aluminum alloy containing the above components can be ≥120 W / m·K. At the same time, the yield strength of the aluminum alloy according to the embodiment of the present application after brazing at 590 - 630 °C is ≥100 MPa, such as ≥120 MPa. The aluminum alloy according to the embodiment of the present application can pass the neutral salt spray test for 720 h. After brazing, the height of the bubbles on the surface of the die-cast part is ≤0.5 mm, such as ≤0.2 mm, or no bubbles. The brazing rate is ≥60%, such as ≥70%, or ≥90%. Thus, during the brazing process, the phenomena of false soldering and void soldering are reduced.

[0063] The aluminum alloy according to the embodiments of the present application, in addition to the above-mentioned elemental components, may further include at least one of the following elements by weight percentage: V 0.01% to 0.5%, Mo 0.01% to 0.5%, Ti 0.01% to 0.5%, Sc 0.01% to 0.5%, Mg 0.01 to 0.5%. For example, in some embodiments, the aluminum alloy may include V with a weight percentage of 0.01% to 0.5%. In some embodiments, the aluminum alloy may include Mo with a weight percentage of 0.01% to 0.5%. In some embodiments, the aluminum alloy may include Ti with a weight percentage of 0.01% to 0.5%. In some embodiments, the aluminum alloy may include Sc with a weight percentage of 0.01% to 0.5%. In some embodiments, the aluminum alloy may include Mg with a weight percentage of 0.01% to 0.5%. Among them, V, Mo, Ti, and Mg can play similar effects to Cr and Zr in the aluminum alloy. Sc can further play a strengthening role in the aluminum alloy to further improve the mechanical properties and corrosion resistance of the aluminum alloy. Thus, the addition of the above elements can help to further improve the melting point, yield strength, thermal conductivity, hardness and other properties of the aluminum alloy.

[0064] Among them, the addition amount of V can be, for example, 0.01%, 0.05%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, or 0.5% or any value between the above two values. The values listed above are all for illustrative purposes. The lower limit value of the addition amount of V can be any of the above values or a value between the above two values; the lower limit value of the addition amount of V can be any of the above values or a value between the above two values. The addition amount of Mo can be, for example, 0.01%, 0.05%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, or 0.5% or any value between the above two values. The values listed above are all for illustrative purposes. The lower limit value of the addition amount of Mo can be any of the above values or a value between the above two values; the lower limit value of the addition amount of Mo can be any of the above values or a value between the above two values. The addition amount of Ti can be, for example, 0.01%, 0.05%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, or 0.5% or any value between the above two values. The values listed above are all for illustrative purposes. The lower limit value of the addition amount of Ti can be any of the above values or a value between the above two values; the lower limit value of the addition amount of Ti can be any of the above values or a value between the above two values. The addition amount of Sc can be, for example, 0.01%, 0.05%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, or 0.5% or any value between the above two values. The values listed above are all for illustrative purposes. The lower limit value of the addition amount of Sc can be any of the above values or a value between the above two values; the lower limit value of the addition amount of Sc can be any of the above values or a value between the above two values. The addition amount of Mg can be, for example, 0.01%, 0.05%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, or 0.5% or any value between the above two values. The values listed above are all for illustrative purposes. The lower limit value of the addition amount of Mg can be any of the above values or a value between the above two values; the lower limit value of the addition amount of Mg can be any of the above values or a value between the above two values.

[0065] It should be noted that the main component of the aluminum alloy in the embodiments of the present application is aluminum. By mass percentage, the sum of the mass percentages of each component is 100%. The inevitable impurities in the embodiments of the present application may be introduced by each component raw material or introduced by production equipment or tooling during the processing and preparation process. Exemplarily, the inevitable impurities may include Si, Cu, Ni, Zn, Ti, Pb, Sn, and other impurities. Among them, the content of each inevitable impurity may be less than or equal to 0.20%. Exemplarily, by weight percentage, the content of Si ≤ 0.2%, such as ≤ 0.12%, the content of Cu ≤ 0.2%, such as ≤ 0.15%, the content of Mg ≤ 0.2%, such as ≤ 0.05%, the content of Ni ≤ 0.2%, such as ≤ 0.05%, the content of Zn ≤ 0.2%, such as ≤ 0.10%, the content of Ti ≤ 0.2%, such as ≤ 0.15%, the content of Pb ≤ 0.2%, such as ≤ 0.02%, the content of Sn ≤ 0.2%, such as ≤ 0.02%, and the total amount of other impurities ≤ 0.4%, such as ≤ 0.3%. In order not to affect the final performance of the aluminum alloy, the content of inevitable impurities can be controlled below 0.4%, and further can be controlled below 0.3%. For example, the content of finally introduced impurities can be controlled by controlling the purity of raw materials and the cleanliness of equipment during the preparation process.

[0066] The composition of the aluminum alloy has been explained above. The preparation method of the aluminum alloy will be further explained below.

[0067] The preparation method of the aluminum alloy in the embodiments of the present application may include the following steps: According to the components of the aluminum alloy of the present application, aluminum and master alloys containing various elements are melted to obtain an alloy melt. The alloy melt is subjected to refining, degassing, and slag removal, and then die-cast to obtain the aluminum alloy. In this way, aluminum alloy castings with specific components can be produced, and the produced aluminum alloy castings have a relatively high melting point, can be used for high-temperature brazing, and also have good mechanical properties, corrosion resistance, and die-casting forming effects.

[0068] Among them, the molten aluminum liquid can be obtained by heating and melting pure aluminum ingots. The pure aluminum ingots can be recycled aluminum raw materials. Other elements can be added in the form of master alloys to reduce production costs. Exemplarily, the master alloy of La and Ce can be, for example, Al-(La,Ce) mixed rare earth master alloy. In the Al-(La,Ce) mixed rare earth master alloy, the mass ratio of La and Ce can be, for example, 30:70 to 50:50, such as 30:70, 35:65, 40:60, 50:50. The master alloy of Fe can be Al-Fe master alloy. The master alloy of Mn can be Al-Mn master alloy. The master alloy of Zr can be Al-Zr master alloy. The master alloy of Cr can be Al-Cr master alloy.

[0069] Exemplarily, the preparation process of the alloy melt is as follows: After cleaning the surface of the aluminum ingot raw material of recycled aluminum, the aluminum ingot is placed in a crucible for heating and melting, and the temperature of the molten aluminum liquid is controlled between 710 and 730 °C. When the temperature of the molten aluminum liquid reaches 710 - 730 °C, the molten aluminum liquid is heated to 780 - 800 °C, and the dried master alloys of each element are added to the molten aluminum liquid and held for 10 - 20 minutes to ensure that all the added master alloys are dissolved evenly.

[0070] It can be understood that, in addition to first melting the pure aluminum ingot and then melting other components, the pure aluminum ingot and various components can also be added together and then heated to obtain the alloy melt, as long as the raw materials weighed according to the components of the aluminum alloy can be mixed and melted. The addition order of each raw material is not limited here.

[0071] The processes of refining, degassing and slag removal are as follows: When the temperature of the alloy melt drops to 730 - 750 °C, a rotary degasser is used to press the sodium-free aluminum alloy refining agent into the molten aluminum liquid for refining. The refining time is, for example, 10 - 30 minutes, and then the slag is removed and the melt is allowed to stand. The standing time is 0.5 - 1.5 hours. After standing, the hydrogen content is detected with a hydrogen detector. When the hydrogen content reaches below 0.3 ml / 100 g, for example, ≤ 0.2 ml / 100 g, die casting is carried out.

[0072] Exemplarily, during the refining, degassing, and slag removal processes, first, a refining agent is added to the alloy melt. A rotary degasser is used to refine and degas the alloy melt with the added refining agent. After the preset time of refining and degassing, slag removal is carried out, and it is left to stand for a period of time. Then, a hydrogen detector is used to detect the hydrogen content in the alloy melt after standing and determine whether the hydrogen content is greater than a threshold value. If it is greater, it means that the hydrogen content in the alloy melt is still relatively high, and further slag removal and degassing treatment are still required, so the above slag removal and degassing process is continued; if it is not greater, it means that the hydrogen content in the alloy melt already meets the requirements. At this time, it can be determined that the slag removal and degassing are completed, and the die-casting process can be carried out. Among them, the threshold value can be designed according to factors such as the influence of the hydrogen content on aluminum alloy castings and the performance requirements for aluminum alloy castings, which are not limited here. For example, but not limited to, the threshold value is set not to exceed 0.3 ml / 100 g. Further, the threshold value can be optimized to 0.2 ml / 100 g. At this time, the hydrogen content in the alloy melt is less than or equal to 0.2 ml / 100 g. And the type of refining agent can be selected according to the actual situation. For example, but not limited to, a sodium-free refining agent is selected, which is not limited here either. It should be understood that when making the alloy melt, at high temperatures, the solubility of hydrogen in the alloy melt is relatively high, making hydrogen extremely soluble in liquid aluminum. During the die-casting process, as the temperature of the alloy melt decreases, the solubility of hydrogen decreases, causing hydrogen to gradually precipitate. If degassing treatment is not carried out before die-casting, defects such as pores and pinholes will be generated in the aluminum alloy castings. These defects will cause the surface of the castings to bubble during high-temperature brazing of the aluminum alloy castings. Therefore, through slag removal and degassing treatment, the bubbling phenomenon of the aluminum alloy castings after high-temperature brazing can be reduced, so that the bubbling height after high-temperature brazing does not exceed 0.5 mm. By further optimizing the threshold value, the bubbling height after high-temperature brazing can be further reduced to within 0.2 mm or there is no bubbling phenomenon.

[0073] Die-casting: The degassed molten aluminum liquid is placed in the cavity for vacuum die-casting. The cavity vacuum degree ≤ 100 mbar, such as ≤ 50 mbar, or 30 mbar for example. By optimizing the vacuum degree, the die-casting effect during vacuum die-casting can be improved, the gas contained in the aluminum alloy castings can be reduced, and thus the mechanical properties of the aluminum alloy castings can be further improved. And, by optimizing the vacuum degree, the bubbling phenomenon of the aluminum alloy castings after die-casting during high-temperature brazing and the fluidity of the alloy melt can be further reduced.

[0074] In the preparation method of the embodiment of the present application, after the alloy melt is degassed and die-cast under high vacuum, the gas content of the die-casting parts is low. After high-temperature brazing, the amount of bubbling can be reduced, and further no bubbling can be achieved. After testing, the bubbling height on the surface of the die-casting parts after brazing ≤ 0.5 mm, and the bubbling height of some die-casting parts ≤ 0.2 mm. Some even have no bubbling at all.

[0075] Based on the same inventive purpose, an embodiment of the present application further provides a die-cast part, which can be formed by using the aluminum alloy of the embodiment of the present application. The die-cast part of the embodiment of the present application can be used for heat dissipation.

[0076] For example, the die-cast part of the embodiment of the present application can be mainly applied to the field of wireless communication, such as massive input massive output (MIMO) and remote radio unit (RRU), and the liquid-cooled heat dissipation box body. It can also be used for components in the field of vehicle heat dissipation, such as modular drivetrain concept (MDC) devices. The aluminum alloy of the present application can be used to prepare heat dissipation plates, radiators and other components of the above devices.

[0077] Based on the same inventive purpose, an embodiment of the present application further provides a welding assembly, which includes a metal matrix and the die-cast part of the embodiment of the present application. The die-cast part can be welded to the metal matrix, such as by tunnel furnace atmosphere protection brazing or vacuum furnace brazing. Among them, the metal matrix can be formed by using the aluminum alloy of the embodiment of the present application, or can be formed by using a weldable aluminum alloy of other components.

[0078] Based on the same inventive purpose, an embodiment of the present application further provides an electronic device, which may include a processing unit and a packaging component. Among them, at least part of the structural components in the packaging component can be obtained by die-casting using the aluminum alloy of the embodiment of the present application.

[0079] The aluminum alloy of the present application will be further described in detail below in conjunction with embodiments.

[0080] Embodiment 1

[0081] This embodiment is a die-cast part, and the composition of its aluminum alloy is: Al-3.17La-5.86Ce-1.3Fe-0.54Mn-0.23Zr-0.22Cr. Among them, La accounts for 3.17% of the total mass of the aluminum alloy. Ce accounts for 5.86% of the total mass of the aluminum alloy. Fe accounts for 1.3% of the total mass of the aluminum alloy. Mn accounts for 0.54% of the total mass of the aluminum alloy. Cr accounts for 0.12% of the total mass of the aluminum alloy. Zr accounts for 0.17% of the total mass of the aluminum alloy. Except for Al, other elements are inevitable impurities. The content of inevitable impurities is listed in Table 2.

[0082] Embodiment 2

[0083] The composition of the aluminum alloy in this embodiment is: Al-2.96La-5.88Ce-1.2Fe-0.85Mn-0.25Zr-0.03Cr.

[0084] Embodiment 3

[0085] The composition of the aluminum alloy in this embodiment is: Al-3.15La-5.85Ce-0.7Fe-0.54Mn-0.23Zr-0.23Cr.

[0086] Example 4

[0087] The composition of the aluminum alloy in this embodiment is: Al-3.14La-5.83Ce-1.3Fe-0.3Mn-0.23Zr-0.22Cr.

[0088] Example 5

[0089] The composition of the aluminum alloy in this embodiment is: Al-3.18La-5.82Ce-1.3Fe-0.56Mn-0.1Zr-0.22Cr.

[0090] Example 6

[0091] The composition of the aluminum alloy in this embodiment is: Al-3.16La-5.85Ce-1.3Fe-0.57Mn-0.23Zr-0.6Cr.

[0092] The composition components of the aluminum alloys of Examples 1-6 are listed in Table 1.

[0093] Comparative Examples 1-3

[0094] Comparative Examples 1-3 are respectively an aluminum alloy, and the composition of the aluminum alloy is listed in Table 3.

[0095] Table 2

[0096] Lanthanum Cerium Iron Manganese Zirconium Chromium Silicon Example 1 3.17％ 5.86％ 1.3％ 0.54％ 0.23％ 0.22％ 0.0388％ Example 2 2.96％ 5.88％ 1.2％ 0.85％ 0.25％ 0.03％ 0.0229％ Example 3 3.15％ 5.85％ 0.7％ 0.54％ 0.23％ 0.23％ 0.0325％ Example 4 3.14％ 5.83％ 1.3％ 0.3％ 0.23％ 0.22％ 0.0278％ Example 5 3.18％ 5.82％ 1.3％ 0.56％ 0.10％ 0.22％ 0.0242％ Example 6 3.16％ 5.85％ 1.3％ 0.57％ 0.23％ 0.60％ 0.0313％

[0097] Table 3

[0098] Serial number Silicon Copper Iron Manganese Nickel Chromium Comparative Example 1 10％ 2.5％ 1.3％ - - - Comparative Example 2 - - 0.6％ 1.6％ - - Comparative Example 3 - - 1.2％ 1.2％ 3％ 0.4％

[0099] Remark: In Table 3, "-" indicates non-existence or existence as inevitable impurity elements.

[0100] The melting points, yield strengths after brazing, tensile strengths after brazing, and thermal conductivities of the aluminum alloys of each example and comparative example were tested respectively. The test results are listed in Table 4. Among them, the process conditions for high-temperature brazing are: tunnel furnace atmosphere protection brazing, welding temperature 600 °C (optional 590 / 600 / 610 / 620 / 630), and the filler metal is 4343 (optional 4045 / 4047).

[0101] Among them, the specific test processes for each parameter are as follows:

[0102] Melting point test: For the cut aluminum alloy casting samples, differential scanning calorimetry (DSC) test was carried out to obtain the melting point.

[0103] Mechanical property test: Standard tensile mechanical test pieces were cut from the aluminum alloys of each example and comparative example according to the requirements of GB / T 228, and the mechanical properties were tested on a tensile testing machine.

[0104] Thermal conductivity test: It was tested by the laser flash method (ASTM E 1561-01), and the sample size was Φ12.7mm×3mm; the specific heat was referred to ISO11357 and ASTM E1269; the density was referred to ISO 1183-1:2004.

[0105] Table 4

[0106]

[0107] From the relevant data in Table 4, it can be seen that for the aluminum alloys of Examples 1-6, since the melting points of the aluminum alloys in the examples of this application are all higher than 620 °C, therefore, the base materials of the aluminum alloys in the examples of this application do not melt during the brazing process. For the aluminum alloy of Comparative Example 1, its melting point temperature is relatively low and it is impossible to achieve brazing welding. Melting phenomenon occurs after brazing welding. For the aluminum alloys of Comparative Example 2 and Comparative Example 3, their melting points are relatively high, but after brazing, the yield strength is too low, less than 60 MPa, and during the installation process, for example, when performing threaded connection, it is easy to have the problem of slipping teeth.

[0108] Among them, from the comparison data of Example 1 and Example 3, it can be seen that when the Fe content is in the range of 1.1%-1.3%, it can help the aluminum alloy die-casting parts to obtain higher yield strength. From the comparison data of Example 1, Example 4 and Example 6, it can be seen that when the aluminum alloy contains Cr, and the content of Cr is in the range of 0.1%-0.25% and the content of Mn is in the range of 0.5%-0.60%, it can help to improve the mechanical properties of the aluminum alloy die-casting parts. From the comparison data of Example 1 and Example 5, it can be seen that when the content of Zr in the aluminum alloy is in the range of 0.2%-0.35%, it can help to improve the mechanical properties of the aluminum alloy die-casting parts.

[0109] After the aluminum alloy die-casting parts in Example 1 were subjected to high-temperature brazing, the brazing rate of the test assembly was detected. Figure 3 It is the surface ultrasonic detection diagram of the die-casting parts after brazing. As Figure 3As shown, the gray area is the filler metal coating area. The brazing rate of the filler metal can reach over 90%, which can weld two aluminum alloy die-castings together well and improve the welding strength. Therefore, the aluminum alloy die-casting provided by the embodiment of the present application can not only be applicable to high-temperature brazing, but also has good welding strength after high-temperature brazing, thereby improving the strength of the structure after welding. In addition, the surface of the aluminum alloy die-casting of the embodiment of the present application does not bulge after brazing.

[0110] Figure 4 It is the DSC test curve graph of the aluminum alloy of Example 1. As Figure 4 shown, the endothermic peak of the aluminum alloy of Example 1 is around 640 °C. It shows that the melting point of the aluminum alloy of the embodiment of the present application is significantly higher than the brazing temperature.

[0111] Figure 5 It is the stress and strain curve of the aluminum alloy of Example 1 after brazing. As Figure 5 shown, the yield strength of the aluminum alloy of Example 1 of the present application can reach over 120 MPa after brazing.

[0112] Figure 6 It is the schematic diagram of the weld seam after brazing the aluminum alloy of Example 1 and other metal components. As Figure 6 shown, the upper part is the aluminum alloy, and the lower part is other metal substrates. After brazing the two, no welding holes appear at the weld seam.

[0113] Figure 7 It is the stress and strain curve of the weld seam of the aluminum alloy of Example 1. Among them, two aluminum alloys of Example 1 are welded to form a symmetric tensile test strip, and the width of the test strip is 10 mm. The weld seam is located in the middle of the two aluminum alloys. As Figure 7 shown, the tensile strength of the weld seam can reach over 100 MPa.

[0114] Figure 8 It is the schematic diagram of the blasting structure after brazing a die-casting structural part and a plate of an embodiment. As Figure 8 shown, among them, the die-casting structural part in Figure (a) is formed by die-casting with the aluminum alloy of the present application, and its structure is complex and can be die-cast in one step. The plate in Figure (b) can be a 3003 plate. After the die-casting structural part and the plate are welded and then separated by blasting, the blasting pressure is 11 MPa. As Figure 8 shown, the high blasting pressure can also reflect that a high-strength sealed connection structure can be formed between the die-casting structural part and the plate of the present application, which can meet the requirements of high-pressure brazing sealing.

[0115] The above is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application can easily think of changes or substitutions, which should all be covered within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. An aluminum alloy, characterized in that based on the total weight of the aluminum alloy, it comprises the following elemental composition by weight percentage: La 0.01% - 15%, Ce 0.01% - 15%, Fe 0.3% - 3%, Mn 0.3% - 3%, Zr 0.01% - 0.5%, the sum of the contents of La and Ce is 3% - 15%, the balance comprises Al and unavoidable impurities, and the content of any impurity element in the unavoidable impurities is less than 0.2%.

2. The aluminum alloy according to claim 1, characterized in that by weight percentage, in the aluminum alloy, the contents of the elements La, Ce, Fe, Mn and Zr are as follows: La 2% - 7%, Ce 5% - 8%, Fe 1.0% - 1.5%, Mn 0.6% - 1% and Zr 0.2% - 0.5%.

3. The aluminum alloy according to claim 1, characterized in that by weight percentage, the aluminum alloy further comprises Cr 0.01% - 0.5%.

4. The aluminum alloy according to claim 3, characterized in that by weight percentage, in the aluminum alloy, the contents of the elements La, Ce, Fe, Mn, Zr and Cr are as follows: La 2% - 7%, Ce 5% - 8%, Fe 1.0% - 1.5%, Mn 0.45% - 0.6%, Zr 0.2% - 0.5% and Cr 0.1% - 0.4%.

5. The aluminum alloy according to any one of claims 1 - 4, characterized in that by weight percentage, the aluminum alloy further comprises at least one of the following elements: Sc 0.01% - 0.5%, V 0.01% - 0.5%, Mo 0.01% - 0.5%, Mg 0.01% - 0.5% and Ti 0.01% - 0.5%.

6. The aluminum alloy according to any one of claims 1 - 5, characterized in that the melting point of the aluminum alloy ≥ 620 °C.

7. The aluminum alloy according to any one of claims 1 - 6, characterized in that the thermal conductivity of the aluminum alloy ≥ 120 W / m·K.

8. The aluminum alloy according to any one of claims 1 - 7, characterized in that the yield strength of the aluminum alloy after brazing at 590 - 630 °C ≥ 80 MPa.

9. A method for preparing an aluminum alloy, characterized in that comprises: According to the composition of the aluminum alloy according to any one of claims 1 - 8, melting the master alloys of each element to obtain an alloy melt, and subjecting the alloy melt to refining, degassing and slag removal and then performing die casting to obtain the aluminum alloy.

10. A die-casting part, characterized in that it is prepared and formed by using the aluminum alloy according to any one of claims 1 - 8.

11. A welded assembly, characterized in that it comprises a metal matrix and the die-casting part according to claim 10, and the die-casting part is brazed and connected to the metal matrix.

12. An electronic device, characterized in that it comprises a processing unit and a packaging component for packaging the processing unit, and at least part of the structural components in the packaging component are die-cast by using the aluminum alloy according to any one of claims 1 - 8.

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