Heat-treatment-free aluminum alloy and preparation method thereof

Abstract

The invention discloses a heat-treatment-free aluminum alloy and a preparation method thereof, and belongs to the technical field of aluminum alloy casting. According to the heat-treatment-free aluminum alloy, the content of Si and the content of Mg are adjusted, the content of Si ranges from 6.1 wt% to 7.9 wt%, the content of Mg ranges from 0.08 wt% to 0.38 wt%, Si and Mg within the content range cooperate with other components, the flowability and mold filling performance of the aluminum alloy can be effectively improved, and therefore the casting performance of the aluminum alloy is improved. And moreover, RE rare earth elements are further added into the aluminum alloy, the strength and fluidity of the aluminum alloy can be effectively improved through the unique second phase effect of the rare earth elements, meanwhile, the fluidity of the aluminum alloy can be improved to a certain extent through the synergistic effect of the microelements V, Ga, Sb and Hf, and therefore the casting performance of the aluminum alloy is further improved.

Description

Technical Field

[0001] The present application relates to the technical field of aluminum alloy casting, and in particular to a heat treatment-free aluminum alloy and a preparation method thereof. Background Art

[0002] At present, vehicle lightweight design has gradually become the development direction of vehicles. Vehicle lightweight design has greatly driven the demand for aluminum in vehicles, and die-casting parts on vehicles prepared by heat-free aluminum alloys have been widely used.

[0003] The heat-treatment-free aluminum alloys in the related art are mainly Al-Si series and Al-Mg series, but the fluidity and filling properties of the heat-treatment-free aluminum alloys of these systems are poor, resulting in poor casting performance. Summary of the invention

[0004] The embodiment of the present application provides a heat-treatment-free aluminum alloy and a preparation method thereof, which can improve the casting performance of the aluminum alloy. The technical solution is as follows:

[0005] In one aspect, a heat-treatment-free aluminum alloy is provided, wherein the heat-treatment-free aluminum alloy comprises the following components in percentage by mass:

[0006] Si: 6.1-7.9wt%, Fe: 0.09-0.35wt%, Cu: 0.01-0.3wt%, Mn: 0.45-0.7wt%, Mg: 0.08-0.38wt%, Ti: 0.06-0.18wt%, Sr: 0.016-0.045wt%, V: 0.01-0.05wt%, Sb: 0.001-0.01wt%, Ga: 0.01-0.025wt%, Hf: 0.01-0.04wt%, RE: 0.005-0.11wt%, the total amount of other impurities is ≤0.2wt%, and the balance is Al;

[0007] Wherein, RE includes at least one of La, Ce and Gd.

[0008] In a possible implementation, the mass percentages of V, Ga, Sb and Hf satisfy 1<K<17;

[0009] in,

[0010] In another possible implementation, the heat treatment-free aluminum alloy includes the following components in percentage by mass:

[0011] Si: 6.1~7.0wt%, Fe: 0.15~0.35wt%, Cu: 0.01~0.2wt%, Mn: 0.45~0.7wt%, Mg: 0.28~0.38wt%, Ti: 0.06~0.18wt%, Sr: 0.016~0.033wt%, V: 0.01~0.03wt%, Sb: 0.001~0.01wt%, Ga: 0.01~0.018wt%, Hf: 0.01~0.025wt%, RE: 0.005~0.06wt%, the total amount of other impurities is ≤0.2wt%, and the balance is Al.

[0012] In another possible implementation, the heat treatment-free aluminum alloy includes the following components in percentage by mass:

[0013] Si: 7.0~7.9wt%, Fe: 0.09~0.22wt%, Cu: 0.1~0.3wt%, Mn: 0.45~0.7wt%, Mg: 0.08~0.28wt%, Ti: 0.06~0.18wt%, Sr: 0.033~0.045wt%, V: 0.03~0.05wt%, Sb: 0.001~0.01wt%, Ga: 0.015~0.025wt%, Hf: 0.02~0.04wt%, RE: 0.05~0.11wt%, the total amount of other impurities is ≤0.2wt%, and the balance is Al.

[0014] In another possible implementation, the heat treatment-free aluminum alloy includes the following components in percentage by mass:

[0015] Si: 6.9wt%, Fe: 0.25wt%, Cu: 0.18wt%, Mn: 0.61wt%, Mg: 0.36wt%, Ti: 0.17wt%, Sr: 0.032wt%, V: 0.016wt%, Sb: 0.0013wt%, Ga: 0.016wt%, Hf: 0.021wt%, RE: 0.06wt%, the total amount of other impurities is ≤ 0.2wt%, and the balance is Al;

[0016] Wherein, RE is industrial pure La-Ce mixed rare earth, and the mixed rare earth includes 40% La and 60% Ce.

[0017] In another possible implementation, the heat treatment-free aluminum alloy includes the following components in percentage by mass:

[0018] Si: 7.5wt%, Fe: 0.19wt%, Cu: 0.26wt%, Mn: 0.63wt%, Mg: 0.28wt%, Ti: 0.15wt%, Sr: 0.039wt%, V: 0.022wt%, Sb: 0.0056wt%, Ga: 0.023wt%, Hf: 0.036wt%, RE: 0.1wt%, the total amount of other impurities is ≤ 0.2wt%, and the balance is Al;

[0019] Among them, RE is industrial pure La rare earth.

[0020] In another possible implementation, Al comes from recycled aluminum, wherein Fe in the recycled aluminum is ≤ 0.35 wt %.

[0021] On the other hand, a method for preparing a heat-treatment-free aluminum alloy is provided, the preparation method comprising:

[0022] Putting the regenerated aluminum into a melting furnace, and after the regenerated aluminum is melted, respectively adding Al-Si master alloy, Al-Cu master alloy, Al-Mn master alloy, Al-Fe master alloy, Al-Ti master alloy, Al-Sr master alloy, Al-V master alloy, Al-Sb master alloy, Al-Hf master alloy and RE rare earth to melt, the temperature of the melting furnace is 750° C.;

[0023] After melting, the temperature is lowered to 720°C and pure Mg and pure Ga are added;

[0024] After pure Mg and pure Ga are melted, the melt is refined and degassed at 720-740°C;

[0025] Take samples to test the composition of the pouring liquid;

[0026] When the composition of the casting liquid is qualified, high-pressure die casting is performed to obtain the heat-treatment-free aluminum alloy.

[0027] In a possible implementation, the high pressure die casting includes the following process parameters:

[0028] Casting pressure 350 ~ 450 bar, injection speed 3 ~ 6 m / s, vacuum degree <50 mbar, die casting temperature 680 ~ 720 ℃, mold temperature 180 ~ 230 ℃.

[0029] In another possible implementation, the content of the refining agent added during refining and degassing is 0.1-0.6 wt %, and the refining and degassing time is 8-13 min.

[0030] The embodiment of the present application provides a heat-treatment-free aluminum alloy, in which the content of Si and Mg is adjusted to be between 6.1 and 7.9 wt%, and the content of Mg is between 0.08 and 0.38 wt%. The Si and Mg in this content range cooperate with other components to effectively improve the fluidity and filling property of the aluminum alloy, thereby improving the casting performance of the aluminum alloy. In addition, RE rare earth elements are added to the aluminum alloy, and the unique second phase effect of rare earth elements can also effectively improve the strength and fluidity of the aluminum alloy. At the same time, the synergistic effect between trace elements V, Ga, Sb and Hf can also improve the fluidity of the aluminum alloy to a certain extent, thereby further improving the casting performance of the aluminum alloy.

[0031] It is to be understood that the foregoing general description and the following detailed description are exemplary only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a preparation flow chart of a heat treatment-free aluminum alloy provided in an embodiment of the present application;

[0033] Figure 2 is a metallographic structure diagram of an aluminum alloy prepared in Example 5 provided in the embodiments of the present application;

[0034] Figure 3 is a metallographic structure diagram of an aluminum alloy prepared in Example 7 provided in the embodiments of the present application;

[0035] Figure 4 This is a scanning electron microscope fracture microscopic morphology image of an aluminum alloy prepared in Example 3 provided in the examples of the present application. DETAILED DESCRIPTION

[0036] In order to make the technical solutions and advantages of the present application clearer, the implementation methods of the present application are described in further detail below.

[0037] On the one hand, an embodiment of the present application provides a heat-treatment-free aluminum alloy, which includes the following components in percentage by mass:

[0038] Si: 6.1-7.9wt%, Fe: 0.09-0.35wt%, Cu: 0.01-0.3wt%, Mn: 0.45-0.7wt%, Mg: 0.08-0.38wt%, Ti: 0.06-0.18wt%, Sr: 0.016-0.045wt%, V: 0.01-0.05wt%, Sb: 0.001-0.01wt%, Ga: 0.01-0.025wt%, Hf: 0.01-0.04wt%, RE: 0.005-0.11wt%, the total amount of other impurities is ≤0.2wt%, and the balance is Al;

[0039] Wherein, RE includes at least one of La, Ce and Gd.

[0040] RE is a rare earth element, including at least one of La, Ce and Gd.

[0041] The embodiment of the present application provides a heat-treatment-free aluminum alloy, in which the contents of Si and Mg are adjusted to be between 6.1 and 7.9 wt%, and the content of Mg is between 0.08 and 0.38 wt%. The Si and Mg in this content range cooperate with other components to effectively improve the fluidity and filling property of the aluminum alloy, thereby improving the casting performance of the aluminum alloy. In addition, RE rare earth elements are added to the aluminum alloy, and the unique second phase effect of rare earth elements can also effectively improve the strength and fluidity of the aluminum alloy, thereby further improving the casting performance of the aluminum alloy.

[0042] Among them, the mass percentage of Si can be 6.1wt%, 6.2wt%, 6.3wt%, 6.4wt%, 6.5wt%, 6.6wt%, 6.7wt%, 6.8wt%, 6.9wt%, 7.0wt%, 7.1wt%, 7.2wt%, 7.3wt%, 7.4wt%, 7.5wt%, 7.6wt%, 7.7wt%, 7.8wt%, 7.9wt%, and the mass percentage of Fe can be 0.09wt%, 0.1wt%, 0.15wt%, 0.17wt%, 0.19wt%, 0.2wt%, 0.23wt%, 0.25wt%, 0.28wt%, 0.3wt%, 0.32wt%, 0.33wt The mass percentage of Cu can be 0.01wt%, 0.03wt%, 0.05wt%, 0.08wt%, 0.1wt%, 0.15wt%, 0.18wt%, 0.2wt%, 0.25wt%, 0.28wt%, 0.3wt%; the mass percentage of Mn can be 0.45wt%, 0.47wt%, 0.48wt%, 0.5wt%, 0.53wt%, 0.55wt%, 0.6wt%, 0.63wt%, 0.65wt%, 0.68wt%, 0.7wt%; the mass percentage of Mg can be 0.08wt%, 0.1wt%, 0.13wt%, 0.15wt%, 0.18wt% The mass percentage of Ti can be 0.06wt%, 0.08wt%, 0.1wt%, 0.13wt%, 0.15wt%, 0.16wt%, 0.18wt%, the mass percentage of Sr can be 0.016wt%, 0.018wt%, 0.02wt%, 0.025wt%, 0.028wt%, 0.03wt%, 0.035wt%, 0.038wt%, 0.04wt%, 0.043wt%, 0.045wt%, and the mass percentage of V can be 0.01wt%, 0. The mass percentage of Sb can be 0.001wt%, 0.002wt%, 0.003wt%, 0.004wt%, 0.005wt%, 0.006wt%, 0.007wt%, 0.008wt%, 0.009wt%, 0.01wt%; the mass percentage of Ga can be 0.01wt%, 0.015wt%, 0.018wt%, 0.02wt%, 0.023wt%, 0.025wt%; and the mass percentage of Hf can be 0.01wt%, 0.0.0.013wt%, 0.015wt%, 0.018wt%, 0.02wt%, 0.025wt%, 0.03wt%, 0.035wt%, 0.04wt%, and the mass percentage of RE can be 0.005wt%, 0.008wt%, 0.01wt%, 0.02wt%, 0.03wt%, 0.04wt%, 0.05wt%, 0.06wt%, 0.07wt%, 0.08wt%, 0.09wt%, 0.1wt%, 0.11wt%. .

[0043] In the embodiment of the present application, the mass percentages of V, Ga, Sb and Hf satisfy 1<K<17;

[0044] in,

[0045] In the formula, V, Ga, Sb and Hf represent the mass percentages of V, Ga, Sb and Hf, respectively.

[0046] Among them, K can be 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, or 16.

[0047] In the embodiment of the present application, by strictly controlling the ratio of trace elements V, Ga, Sb and Hf, the range of the optimal composition is narrowed, and when the mass percentage of V, Ga, Sb and Hf satisfies 1<K<17, the comprehensive performance of the aluminum alloy is optimal. Within this range, the synergistic effect between several alloying elements can achieve certain good effects, which is reflected in the fact that the aluminum alloy can effectively control the precipitation of needle-shaped Fe-rich phases and achieve effective control of the size, distribution and morphology of the Fe-rich phase; in addition, the synergistic effect between trace elements can also improve the flow properties of the aluminum alloy to a certain extent. The mechanism is mainly to reduce the liquidus temperature of the aluminum alloy and increase the superheat of the melt, thereby improving the flow properties of the aluminum alloy.

[0048] In a possible implementation, the heat treatment-free aluminum alloy includes the following components in percentage by mass:

[0049] Si: 6.1~7.0wt%, Fe: 0.15~0.35wt%, Cu: 0.01~0.2wt%, Mn: 0.45~0.7wt%, Mg: 0.28~0.38wt%, Ti: 0.06~0.18wt%, Sr: 0.016~0.033wt%, V: 0.01~0.03wt%, Sb: 0.001~0.01wt%, Ga: 0.01~0.018wt%, Hf: 0.01~0.025wt%, RE: 0.005~0.06wt%, the total amount of other impurities is ≤0.2wt%, and the balance is Al.

[0050] In a possible implementation, the heat treatment-free aluminum alloy includes the following components in percentage by mass:

[0051] Si: 7.0~7.9wt%, Fe: 0.09~0.22wt%, Cu: 0.1~0.3wt%, Mn: 0.45~0.7wt%, Mg: 0.08~0.28wt%, Ti: 0.06~0.18wt%, Sr: 0.033~0.045wt%, V: 0.03~0.05wt%, Sb: 0.001~0.01wt%, Ga: 0.015~0.025wt%, Hf: 0.02~0.04wt%, RE: 0.05~0.11wt%, the total amount of other impurities is ≤0.2wt%, and the balance is Al.

[0052] In a possible implementation, the heat treatment-free aluminum alloy includes the following components in percentage by mass:

[0053] Si: 6.9wt%, Fe: 0.25wt%, Cu: 0.18wt%, Mn: 0.61wt%, Mg: 0.36wt%, Ti: 0.17wt%, Sr: 0.032wt%, V: 0.016wt%, Sb: 0.0013wt%, Ga: 0.016wt%, Hf: 0.021wt%, RE: 0.06wt%, the total amount of other impurities is ≤ 0.2wt%, and the balance is Al;

[0054] Among them, RE is industrial pure La-Ce mixed rare earth, and the mixed rare earth includes 40% La and 60% Ce.

[0055] In a possible implementation, the heat treatment-free aluminum alloy includes the following components in percentage by mass:

[0056] Si: 7.5wt%, Fe: 0.19wt%, Cu: 0.26wt%, Mn: 0.63wt%, Mg: 0.28wt%, Ti: 0.15wt%, Sr: 0.039wt%, V: 0.022wt%, Sb: 0.0056wt%, Ga: 0.023wt%, Hf: 0.036wt%, RE: 0.1wt%, the total amount of other impurities is ≤ 0.2wt%, and the balance is Al;

[0057] Among them, RE is industrial pure La rare earth.

[0058] In a possible implementation, Al comes from recycled aluminum, and Fe in the recycled aluminum is ≤ 0.35 wt %.

[0059] One thing that needs to be explained is that in the related art, primary aluminum is used as raw material to prepare aluminum alloys, but the carbon emissions of primary aluminum are very large, which is not conducive to achieving the goal of carbon neutrality. This application uses recycled aluminum as raw material to prepare aluminum alloys, which can reduce carbon by 98.6% compared with primary aluminum, greatly reducing carbon emissions, and the recycled aluminum itself has the alloying elements such as Mg, Si, and Mn required for aluminum alloys, which can reduce manufacturing costs and ultimately achieve low-carbon sustainable circular production for enterprises.

[0060] This application conducts in-depth research based on the current mainstream Al-Si-Cu and Al-Si-Mg series heat-treatment-free aluminum alloys. By adding trace elements V, Ga, Sb, Hf and RE rare earths, the synergistic effect between different elements reaches a good equilibrium state, thereby making the comprehensive performance of the aluminum alloy higher than the level of current heat-treatment-free aluminum alloys.

[0061] The present application adjusts the Si content within a certain range so that the aluminum alloy has good casting properties. The aluminum alloy has good fluidity and filling properties at a certain temperature, and can quickly and stably fill the far ends of complex, large or super-large castings and positions with poor filling, thereby ensuring the stability of the casting structure and size, while reducing the occurrence of defects such as looseness and shrinkage cavities, and is suitable for the production of large integrated die castings.

[0062] Compared with most heat-free aluminum alloys, the Fe content is not high, and the Fe content is generally required to be no more than 0.15wt%. In this application, the Fe content can reach up to 0.35wt%, and its advantage is that the tolerance to the Fe content in the aluminum alloy is greatly improved, so it is very suitable for production with recycled aluminum. And the high Fe content of recycled aluminum itself can reduce the tendency of aluminum alloy to stick to the mold. Using recycled aluminum as a raw material can well solve the problem that the current heat-free aluminum alloy is easy to stick to the mold. But at the same time, the harm caused by the high Fe content will reduce the mechanical properties of the alloy, mainly because Fe forms more flaky and long iron-rich phases in the aluminum alloy matrix, which splits the matrix structure. In this application, a trace amount of V is added to the aluminum alloy to form a nearly spherical AlFeSi (Mn + V) phase with Al, Fe, Si, and Mn, which effectively reduces the harmful Fe phase effect in the matrix. V also plays a role in refining pre-crystallization to a certain extent, greatly improving the elongation of the aluminum alloy.

[0063] Ti is mainly a grain refiner, which can form a large number of Al3Ti particles in the aluminum matrix, increase the crystallization core and promote nucleation, and can also improve the supercooling of the melt to refine the grains, thereby improving the strength and plasticity of the aluminum alloy. Cu mainly plays a role in solid solution strengthening, and can also maintain the stability of the aging precipitation phase of the aluminum alloy, which can make the aging structure more dispersed and uniform, improve the strength while improving the plasticity of the aluminum alloy, and improve the stress corrosion resistance of the aluminum alloy. Sr mainly plays a metamorphic role, which transforms the eutectic Si from a needle-like structure to a fine granular and worm-like structure, and can also play a role in refining α-Al. Mn can improve the strength and hardness of the aluminum alloy, and work together with Fe to reduce the tendency of the aluminum alloy to stick to the mold. Mg mainly plays a role in improving the yield strength of the aluminum alloy, and has the effect of improving the fluidity of the aluminum alloy and improving the corrosion resistance.

[0064] The role of RE rare earth elements in aluminum alloys is very significant. The unique second phase strengthening effect of rare earth compounds can effectively improve the strength of aluminum alloys, improve the fluidity of aluminum alloys, purify aluminum liquid, reduce the gas content in the die-casting process, etc., which has a significant improvement effect on the overall performance of aluminum alloys.

[0065] In addition, adding trace Ga to aluminum alloy can improve the distribution of grains. The main mechanism is that when Mn and Mg are added to the aluminum alloy matrix, the distribution uniformity of α-Al grains in the matrix will be disturbed. Ga has a certain driving effect on the grain boundary in the pre-crystallization formation stage of aluminum alloy, which can effectively reduce the generation of pre-crystallization of aluminum alloy. In addition, it can also promote the precipitation of Mg2Si strengthening phase at the grain boundary. Adding trace Hf to aluminum alloy can also greatly enhance the heterogeneous nucleation ability of aluminum alloy and enhance the grain refinement. Hf can also form Al3Hf in the aluminum alloy matrix. Al3Hf is a high-temperature stable compound that can improve the heat resistance of aluminum alloy. Na is easily adsorbed on the surface of dendrites or grain boundaries during solidification to form NaAlSi compounds, resulting in brittle cracking, namely "Na brittle" phenomenon. Adding trace element Sb to the matrix can generate Na3Sb compounds, so that Na forms NaCl and is discharged into the slag. Adding trace Sb to aluminum alloy can reduce the probability of "Na brittleness" and play an important role in improving the toughness of aluminum alloy.

[0066] On the other hand, the present invention provides a method for preparing an aluminum alloy without heat treatment. Figure 1 , the preparation method comprises:

[0067] Step 101: Put the regenerated aluminum into a melting furnace, and after the regenerated aluminum is melted, add Al-Si master alloy, Al-Cu master alloy, Al-Mn master alloy, Al-Fe master alloy, Al-Ti master alloy, Al-Sr master alloy, Al-V master alloy, Al-Sb master alloy, Al-Hf master alloy and RE rare earth respectively for melting.

[0068] First, prepare the materials according to the alloy composition ratio, calculate the required mass of each raw material, and then preheat and dry each raw material. Set the furnace temperature to 750°C, put the recycled aluminum into the melting furnace, and after the recycled aluminum is melted, add Al-Si master alloy, Al-Cu master alloy, Al-Mn master alloy, Al-Fe master alloy, Al-Ti master alloy, Al-Sr master alloy, Al-V master alloy, Al-Sb master alloy, Al-Hf master alloy and RE rare earth respectively for melting.

[0069] Among them, the Fe content in the recycled aluminum is ≤0.35wt%.

[0070] Step 102: After melting, the temperature is lowered to 720°C, and pure Mg and pure Ga are added.

[0071] After the above raw materials are melted, the melting furnace is cooled to 720°C, and then pure Mg is added and pressed into the bottom of the melting furnace with a bell tool to prevent Mg from burning on the liquid surface. The same method is used to press Ga wrapped in aluminum foil into the bottom of the melting furnace to prevent Ga from burning on the liquid surface.

[0072] Step 103: After pure Mg and pure Ga are melted, the melt is refined and degassed at 720-740°C.

[0073] After pure Mg and pure Ga are melted, the melt is refined and degassed at 720-740°C.

[0074] The refining agent is added during the refining and degassing of the melt, the content of the refining agent is 0.1-0.6wt%, and the refining and degassing time is 8-13min. The content of the refining agent mentioned in this application is the mass percentage of the mass of the refining agent to the total mass of each alloy component.

[0075] The refining agent may be an oxide, a halide or a metal alloy, etc., and is not specifically limited thereto. For example, the refining agent is an oxide, and the oxide may be aluminum oxide or magnesium oxide. The refining agent is a halide, and the halide may be potassium chloride or sodium chloride.

[0076] The content of refining agent can be 0.1wt%, 0.2wt%, 0.3wt%, 0.4wt%, 0.5wt%, 0.6wt%, the time of refining and degassing can be 8min, 9min, 10min, 11min, 12min, 13min, and the temperature of refining and degassing can be 720℃, 725℃, 730℃, 735℃, 740℃.

[0077] Step 104: sampling and testing the composition of the casting liquid.

[0078] Take samples from the melting furnace and perform element spectrum analysis on the casting liquid. The composition of the casting liquid is detected by element spectrum analysis to determine whether the elements in the casting liquid and the content of each element are within the corresponding range. If the types of elements in the casting liquid are the same as its alloy composition and the content of each element is within the corresponding range, the composition of the casting liquid is determined to be qualified.

[0079] Step 105: When the composition of the casting liquid is qualified, high-pressure die casting is performed to obtain an aluminum alloy that does not require heat treatment.

[0080] Among them, high-pressure die casting includes the following process parameters: casting pressure 350-450 bar, injection speed 3-6 m / s, vacuum degree <50 mbar, die casting temperature 680-720°C, and mold temperature 180-230°C.

[0081] The casting pressure can be 350bar, 380bar, 390bar, 400bar, 410bar, 430bar, 450bar, the injection speed can be 3m / s, 4m / s, 5m / s, 6m / s, the vacuum degree can be 10mbar, 15mbar, 20mbar, 25mbar, 30mbar, 35mbar, 40mbar, 45mbar, 48mbar, 49mbar, the die-casting temperature can be 680℃, 690℃, 700℃, 710℃, 715℃, 718℃, 720℃, and the mold temperature can be 180℃, 190℃, 200℃, 210℃, 220℃, 230℃.

[0082] It should be noted that after executing step 104, step 105 can be executed directly, or the pouring liquid in the melting furnace can be poured into the mold cavity to obtain an aluminum alloy ingot, and then the aluminum alloy ingot is melted and high-pressure die-casting is performed to obtain a heat-treatment-free aluminum alloy.

[0083] In practical applications, steps 101 to 104 may be performed by one supplier, and step 105 may be performed by another supplier. Therefore, after step 104 is performed, transportation issues may be involved. Compared with the pouring liquid, the aluminum alloy ingot is easier to transport. Therefore, the pouring liquid can be poured into the mold cavity to obtain the aluminum alloy ingot. Then another supplier melts the aluminum alloy ingot and performs high-pressure die casting to obtain the aluminum alloy without heat treatment.

[0084] The heat-treatment-free aluminum alloy prepared by the above method in the present application can achieve a tensile strength of more than 280MPa in the cast state, a yield strength of more than 140Mpa, an elongation of more than 15%, a maximum fluidity mold test length of 1150mm, and a maximum bending angle of 41.1°. In addition, the aluminum alloy prepared in the present application is a heat-treatment-free aluminum alloy. No heat treatment is required to obtain an aluminum alloy with excellent comprehensive performance, which is suitable for die-casting of complex structure, thin-walled and high-strength automotive parts, thereby achieving the goal of lightweighting the automobile. Among them, the heat-treatment-free aluminum alloy provided in the present application can be applied to shock towers, front cabins, rear floors and other parts of automobiles, without specific limitation.

[0085] In addition, the aluminum alloy prepared in this application does not stick to the mold during the die casting process, and its flow properties are similar to those of AlSi 10 MnMg is equivalent, and the test pieces of the casting body are taken for mechanical property testing, bending angle testing, metallographic structure observation, and fracture microscopic scanning analysis. The results show that the aluminum alloy has both high yield strength and high elongation, large bending angle, and the material does not crack during riveting. The α-Al grains in the metallographic structure are small and evenly distributed. The fracture morphology is a typical ductile fracture, and the dimples are densely distributed and uniform in size, indicating that the material has the characteristics of high strength and high toughness. Among them, AlSi 10 MnMg is a common material for current aluminum alloys, with Al, Si, Mn and Mg as the main components.

[0086] The technical solution of the present application will be described in detail below through specific embodiments.

[0087] In the following specific examples, operations involved without specifying conditions were performed under conventional conditions or conditions recommended by the manufacturer.

[0088] Example 1

[0089] This embodiment provides a heat-treatment-free aluminum alloy, which includes the following components in percentage by mass:

[0090] Si: 6.1wt%, Fe: 0.3wt%, Cu: 0.05wt%, Mn: 0.65wt%, Mg: 0.38wt%, Ti: 0.15wt%, Sr: 0.031wt%, V: 0.02wt%, Sb: 0.01wt%, Ga: 0.02wt%, Hf: 0.02wt%, RE: 0.11wt%, the total amount of other impurities is less than 0.2wt%, and the balance is Al. Among them, RE is industrial pure La-Ce mixed rare earth, which includes 40% La and 60% Ce.

[0091] The preparation method of the heat treatment-free aluminum alloy is as follows:

[0092] Step 1: Prepare the materials according to the alloy composition ratio, calculate the required mass of each raw material, and then preheat and dry each raw material. Set the furnace temperature to 750°C, put the recycled aluminum into the melting furnace, and after the recycled aluminum is melted, add Al-Si master alloy, Al-Cu master alloy, Al-Mn master alloy, Al-Fe master alloy, Al-Ti master alloy, Al-Sr master alloy, Al-V master alloy, Al-Sb master alloy, Al-Hf master alloy and RE rare earth respectively for melting.

[0093] Among them, the Fe content in the recycled aluminum is ≤0.35wt%.

[0094] Step 2: After melting, cool to 720°C, add pure Mg, and use a bell tool to press Mg into the bottom of the melting furnace to prevent Mg from burning on the liquid surface. Use the same method to press Ga wrapped in aluminum foil into the bottom of the melting furnace to prevent Ga from burning on the liquid surface.

[0095] Step 3: After pure Mg and pure Ga are melted, the melt is refined and degassed at 740° C., the amount of refining agent added is 0.2 wt %, and the refining and degassing time is 10 min.

[0096] Step 4: Take samples to test the composition of the casting liquid. If the composition of the casting liquid is qualified, high-pressure die casting is performed to obtain the aluminum alloy without heat treatment.

[0097] Among them, the process parameters of high-pressure die casting are: casting pressure 400bar, injection speed 5m / s, vacuum degree 30mbar, die casting temperature 700℃, and mold temperature 190℃.

[0098] The die-casting mold is a flat mold and a flow mold. Then, tensile test pieces and bending test pieces are taken from the flat mold casting body for tensile performance testing, flow performance testing, bending angle testing, metallographic structure and fracture microscopic analysis.

[0099] Example 2

[0100] This embodiment provides a heat-treatment-free aluminum alloy, which includes the following components in percentage by mass:

[0101] Si: 6.8wt%, Fe: 0.35wt%, Cu: 0.1wt%, Mn: 0.65wt%, Mg: 0.3wt%, Ti: 0.08wt%, Sr: 0.04wt%, V: 0.03wt%, Sb: 0.0065wt%, Ga: 0.018wt%, Hf: 0.035wt%, RE: 0.08wt%, the total amount of other impurities is less than 0.2wt%, and the balance is Al. Among them, RE is industrial pure La-Ce-Gd mixed rare earth, which includes 40% La, 50% Ce and 10% Gd.

[0102] The preparation method of the heat treatment-free aluminum alloy is as follows:

[0103] Step 1: Prepare the materials according to the alloy composition ratio, calculate the required mass of each raw material, and then preheat and dry each raw material. Set the furnace temperature to 750°C, put the recycled aluminum into the melting furnace, and after the recycled aluminum is melted, add Al-Si master alloy, Al-Cu master alloy, Al-Mn master alloy, Al-Fe master alloy, Al-Ti master alloy, Al-Sr master alloy, Al-V master alloy, Al-Sb master alloy, Al-Hf master alloy and RE rare earth respectively for melting.

[0104] Among them, the Fe content in the recycled aluminum is ≤0.35wt%.

[0105] Step 2: After melting, cool to 720°C, add pure Mg, and use a bell tool to press Mg into the bottom of the melting furnace to prevent Mg from burning on the liquid surface. Use the same method to press Ga wrapped in aluminum foil into the bottom of the melting furnace to prevent Ga from burning on the liquid surface.

[0106] Step 3: After pure Mg and pure Ga are melted, the melt is refined and degassed at 740° C., the amount of refining agent added is 0.2 wt %, and the refining and degassing time is 10 min.

[0107] Step 4: Take samples to test the composition of the casting liquid. If the composition of the casting liquid is qualified, high-pressure die casting is performed to obtain the aluminum alloy without heat treatment.

[0108] Among them, the process parameters of high-pressure die-casting are: casting pressure 350bar, injection speed 6m / s, vacuum degree 25mbar, die-casting temperature 700℃, and mold temperature 195℃.

[0109] The die-casting mold is a flat mold and a flow mold. Then, tensile test pieces and bending test pieces are taken from the flat mold casting body for tensile performance testing, flow performance testing, bending angle testing, metallographic structure and fracture microscopic analysis.

[0110] Example 3

[0111] This embodiment provides a heat-treatment-free aluminum alloy, which includes the following components in percentage by mass:

[0112] Si: 6.9wt%, Fe: 0.25wt%, Cu: 0.18wt%, Mn: 0.61wt%, Mg: 0.36wt%, Ti: 0.17wt%, Sr: 0.032wt%, V: 0.016wt%, Sb: 0.0013wt%, Ga: 0.016wt%, Hf: 0.021wt%, RE: 0.06wt%, the total amount of other impurities is less than 0.2wt%, and the balance is Al. Among them, RE is industrial pure La-Ce mixed rare earth, which includes 40% La and 60% Ce.

[0113] The preparation method of the heat treatment-free aluminum alloy is as follows:

[0114] Step 1: Prepare the materials according to the alloy composition ratio, calculate the required mass of each raw material, and then preheat and dry each raw material. Set the furnace temperature to 760°C, put the recycled aluminum into the melting furnace, and after the recycled aluminum is melted, add Al-Si master alloy, Al-Cu master alloy, Al-Mn master alloy, Al-Fe master alloy, Al-Ti master alloy, Al-Sr master alloy, Al-V master alloy, Al-Sb master alloy, Al-Hf master alloy and RE rare earth respectively for melting.

[0115] Among them, the Fe content in the recycled aluminum is ≤0.35wt%.

[0116] Step 2: After melting, cool to 720°C, add pure Mg, and use a bell tool to press Mg into the bottom of the melting furnace to prevent Mg from burning on the liquid surface. Use the same method to press Ga wrapped in aluminum foil into the bottom of the melting furnace to prevent Ga from burning on the liquid surface.

[0117] Step 3: After pure Mg and pure Ga are melted, the melt is refined and degassed at 735° C., the amount of refining agent added is 0.4 wt %, and the refining and degassing time is 12 min.

[0118] Step 4: Take samples to test the composition of the casting liquid. If the composition of the casting liquid is qualified, high-pressure die casting is performed to obtain the aluminum alloy without heat treatment.

[0119] Among them, the process parameters of high-pressure die-casting are: casting pressure 450bar, injection speed 6m / s, vacuum degree 25mbar, die-casting temperature 700℃, and mold temperature 180℃.

[0120] The die-casting mold is a flat mold and a flow mold. Then, tensile test pieces and bending test pieces are taken from the flat mold casting body for tensile performance testing, flow performance testing, bending angle testing, metallographic structure and fracture microscopic analysis.

[0121] Example 4

[0122] This embodiment provides a heat-treatment-free aluminum alloy, which includes the following components in percentage by mass:

[0123] Si: 7.0wt%, Fe: 0.26wt%, Cu: 0.2wt%, Mn: 0.7wt%, Mg: 0.28wt%, Ti: 0.13wt%, Sr: 0.045wt%, V: 0.05wt%, Sb: 0.0032wt%, Ga: 0.025wt%, Hf: 0.025wt%, RE: 0.05wt%, the total amount of other impurities is less than 0.2wt%, and the balance is Al. Among them, RE is industrial pure Ce rare earth.

[0124] The preparation method of the heat treatment-free aluminum alloy is as follows:

[0125] Step 1: Prepare the materials according to the alloy composition ratio, calculate the required mass of each raw material, and then preheat and dry each raw material. Set the furnace temperature to 750°C, put the recycled aluminum into the melting furnace, and after the recycled aluminum is melted, add Al-Si master alloy, Al-Cu master alloy, Al-Mn master alloy, Al-Fe master alloy, Al-Ti master alloy, Al-Sr master alloy, Al-V master alloy, Al-Sb master alloy, Al-Hf master alloy and RE rare earth respectively for melting.

[0126] Among them, the Fe content in the recycled aluminum is ≤0.35wt%.

[0127] Step 2: After melting, cool to 720°C, add pure Mg, and use a bell tool to press Mg into the bottom of the melting furnace to prevent Mg from burning on the liquid surface. Use the same method to press Ga wrapped in aluminum foil into the bottom of the melting furnace to prevent Ga from burning on the liquid surface.

[0128] Step 3: After pure Mg and pure Ga are melted, the melt is refined and degassed at 730° C., the amount of refining agent added is 0.5 wt %, and the refining and degassing time is 12 min.

[0129] Step 4: Take samples to test the composition of the casting liquid. If the composition of the casting liquid is qualified, high-pressure die casting is performed to obtain the aluminum alloy without heat treatment.

[0130] Among them, the process parameters of high-pressure die-casting are: casting pressure 450bar, injection speed 6m / s, vacuum degree 25mbar, die-casting temperature 700℃, and mold temperature 180℃.

[0131] The die-casting mold is a flat mold and a flow mold. Then, tensile test pieces and bending test pieces are taken from the flat mold casting body for tensile performance testing, flow performance testing, bending angle testing, metallographic structure and fracture microscopic analysis.

[0132] Example 5

[0133] This embodiment provides a heat-treatment-free aluminum alloy, which includes the following components in percentage by mass:

[0134] Si: 7.2wt%, Fe: 0.22wt%, Cu: 0.19wt%, Mn: 0.59wt%, Mg: 0.28wt%, Ti: 0.18wt%, Sr: 0.016wt%, V: 0.035wt%, Sb: 0.0046wt%, Ga: 0.019wt%, Hf: 0.03wt%, RE: 0.015wt%, the total amount of other impurities is less than 0.2wt%, and the balance is Al. Among them, RE is industrial pure La-Ce mixed rare earth, which includes 40% La and 60% Ce.

[0135] The preparation method of the heat treatment-free aluminum alloy is as follows:

[0136] Step 1: Prepare the materials according to the alloy composition ratio, calculate the required mass of each raw material, and then preheat and dry each raw material. Set the furnace temperature to 740°C, put the recycled aluminum into the melting furnace, and after the recycled aluminum is melted, add Al-Si master alloy, Al-Cu master alloy, Al-Mn master alloy, Al-Fe master alloy, Al-Ti master alloy, Al-Sr master alloy, Al-V master alloy, Al-Sb master alloy, Al-Hf master alloy and RE rare earth respectively for melting.

[0137] Among them, the Fe content in the recycled aluminum is ≤0.35wt%.

[0138] Step 2: After melting, cool to 720°C, add pure Mg, and use a bell tool to press Mg into the bottom of the melting furnace to prevent Mg from burning on the liquid surface. Use the same method to press Ga wrapped in aluminum foil into the bottom of the melting furnace to prevent Ga from burning on the liquid surface.

[0139] Step 3: After pure Mg and pure Ga are melted, the melt is refined and degassed at 720° C., the amount of refining agent added is 0.6 wt %, and the refining and degassing time is 12 min.

[0140] Step 4: Take samples to test the composition of the casting liquid. If the composition of the casting liquid is qualified, high-pressure die casting is performed to obtain the aluminum alloy without heat treatment.

[0141] Among them, the process parameters of high-pressure die casting are: casting pressure 400bar, injection speed 3.5m / s, vacuum degree 35mbar, die casting temperature 690℃, and mold temperature 200℃.

[0142] The die-casting mold is a flat mold and a flow mold. Then, tensile test pieces and bending test pieces are taken from the flat mold casting body for tensile performance testing, flow performance testing, bending angle testing, metallographic structure and fracture microscopic analysis.

[0143] Example 6

[0144] This embodiment provides a heat-treatment-free aluminum alloy, which includes the following components in percentage by mass:

[0145] Si: 7.3wt%, Fe: 0.24wt%, Cu: 0.09wt%, Mn: 0.62wt%, Mg: 0.27wt%, Ti: 0.14wt%, Sr: 0.022wt%, V: 0.045wt%, Sb: 0.0013wt%, Ga: 0.015wt%, Hf: 0.028wt%, RE: 0.005wt%, the total amount of other impurities is less than 0.2wt%, and the balance is Al. Among them, RE is industrial pure La-Ce-Gd mixed rare earth, which includes 40% La, 50% Ce and 10% Gd.

[0146] The preparation method of the heat treatment-free aluminum alloy is as follows:

[0147] Step 1: Prepare the materials according to the alloy composition ratio, calculate the required mass of each raw material, and then preheat and dry each raw material. Set the furnace temperature to 750°C, put the recycled aluminum into the melting furnace, and after the recycled aluminum is melted, add Al-Si master alloy, Al-Cu master alloy, Al-Mn master alloy, Al-Fe master alloy, Al-Ti master alloy, Al-Sr master alloy, Al-V master alloy, Al-Sb master alloy, Al-Hf master alloy and RE rare earth respectively for melting.

[0148] Among them, the Fe content in the recycled aluminum is ≤0.35wt%.

[0149] Step 2: After melting, cool to 720°C, add pure Mg, and use a bell tool to press Mg into the bottom of the melting furnace to prevent Mg from burning on the liquid surface. Use the same method to press Ga wrapped in aluminum foil into the bottom of the melting furnace to prevent Ga from burning on the liquid surface.

[0150] Step 3: After pure Mg and pure Ga are melted, the melt is refined and degassed at 730° C., the amount of refining agent added is 0.3 wt%, and the refining and degassing time is 12 min.

[0151] Step 4: Take samples to test the composition of the casting liquid. If the composition of the casting liquid is qualified, high-pressure die casting is performed to obtain the aluminum alloy without heat treatment.

[0152] Among them, the process parameters of high-pressure die-casting are: casting pressure 350bar, injection speed 3m / s, vacuum degree 28mbar, die-casting temperature 700℃, and mold temperature 210℃.

[0153] The die-casting mold is a flat mold and a flow mold. Then, tensile test pieces and bending test pieces are taken from the flat mold casting body for tensile performance testing, flow performance testing, bending angle testing, metallographic structure and fracture microscopic analysis.

[0154] Example 7

[0155] This embodiment provides a heat-treatment-free aluminum alloy, which includes the following components in percentage by mass:

[0156] Si: 7.5wt%, Fe: 0.19wt%, Cu: 0.26wt%, Mn: 0.63wt%, Mg: 0.28wt%, Ti: 0.15wt%, Sr: 0.039wt%, V: 0.022wt%, Sb: 0.0056wt%, Ga: 0.023wt%, Hf: 0.036wt%, RE: 0.1wt%, the total amount of other impurities is less than 0.2wt%, and the balance is Al. Among them, RE is industrial pure La rare earth.

[0157] The preparation method of the heat treatment-free aluminum alloy is as follows:

[0158] Step 1: Prepare the materials according to the alloy composition ratio, calculate the required mass of each raw material, and then preheat and dry each raw material. Set the furnace temperature to 750°C, put the recycled aluminum into the melting furnace, and after the recycled aluminum is melted, add Al-Si master alloy, Al-Cu master alloy, Al-Mn master alloy, Al-Fe master alloy, Al-Ti master alloy, Al-Sr master alloy, Al-V master alloy, Al-Sb master alloy, Al-Hf master alloy and RE rare earth respectively for melting.

[0159] Among them, the Fe content in the recycled aluminum is ≤0.35wt%.

[0160] Step 2: After melting, cool to 720°C, add pure Mg, and use a bell tool to press Mg into the bottom of the melting furnace to prevent Mg from burning on the liquid surface. Use the same method to press Ga wrapped in aluminum foil into the bottom of the melting furnace to prevent Ga from burning on the liquid surface.

[0161] Step 3: After pure Mg and pure Ga are melted, the melt is refined and degassed at 740° C., the amount of refining agent added is 0.4 wt %, and the refining and degassing time is 8 min.

[0162] Step 4: Take samples to test the composition of the casting liquid. If the composition of the casting liquid is qualified, high-pressure die casting is performed to obtain the aluminum alloy without heat treatment.

[0163] Among them, the process parameters of high-pressure die-casting are: casting pressure 400 bar, injection speed 4.5 m / s, vacuum degree 31 mbar, die-casting temperature 700°C, and mold temperature 195°C.

[0164] The die-casting mold is a flat mold and a flow mold. Then, tensile test pieces and bending test pieces are taken from the flat mold casting body for tensile performance testing, flow performance testing, bending angle testing, metallographic structure and fracture microscopic analysis.

[0165] Example 8

[0166] This embodiment provides a heat-treatment-free aluminum alloy, which includes the following components in percentage by mass:

[0167] Si: 7.6wt%, Fe: 0.15wt%, Cu: 0.28wt%, Mn: 0.55wt%, Mg: 0.19wt%, Ti: 0.06wt%, Sr: 0.032wt%, V: 0.026wt%, Sb: 0.0033wt%, Ga: 0.01wt%, Hf: 0.01wt%, RE: 0.008wt%, the total amount of other impurities is less than 0.2wt%, and the balance is Al. Among them, RE is industrial pure Ce rare earth.

[0168] The preparation method of the heat treatment-free aluminum alloy is as follows:

[0169] Step 1: Prepare the materials according to the alloy composition ratio, calculate the required mass of each raw material, and then preheat and dry each raw material. Set the furnace temperature to 760°C, put the recycled aluminum into the melting furnace, and after the recycled aluminum is melted, add Al-Si master alloy, Al-Cu master alloy, Al-Mn master alloy, Al-Fe master alloy, Al-Ti master alloy, Al-Sr master alloy, Al-V master alloy, Al-Sb master alloy, Al-Hf master alloy and RE rare earth respectively for melting.

[0170] Among them, the Fe content in the recycled aluminum is ≤0.35wt%.

[0171] Step 2: After melting, cool to 720°C, add pure Mg, and use a bell tool to press Mg into the bottom of the melting furnace to prevent Mg from burning on the liquid surface. Use the same method to press Ga wrapped in aluminum foil into the bottom of the melting furnace to prevent Ga from burning on the liquid surface.

[0172] Step 3: After pure Mg and pure Ga are melted, the melt is refined and degassed at 730° C., the amount of refining agent added is 0.1 wt%, and the refining and degassing time is 12 min.

[0173] Step 4: Take samples to test the composition of the casting liquid. If the composition of the casting liquid is qualified, high-pressure die casting is performed to obtain the aluminum alloy without heat treatment.

[0174] Among them, the process parameters of high-pressure die-casting are: casting pressure 450 bar, injection speed 5.5 m / s, vacuum degree 30 mbar, die-casting temperature 720°C, and mold temperature 220°C.

[0175] The die-casting mold is a flat mold and a flow mold. Then, tensile test pieces and bending test pieces are taken from the flat mold casting body for tensile performance testing, flow performance testing, bending angle testing, metallographic structure and fracture microscopic analysis.

[0176] Example 9

[0177] This embodiment provides a heat-treatment-free aluminum alloy, which includes the following components in percentage by mass:

[0178] Si: 7.8wt%, Fe: 0.09wt%, Cu: 0.3wt%, Mn: 0.45wt%, Mg: 0.23wt%, Ti: 0.10wt%, Sr: 0.035wt%, V: 0.018wt%, Sb: 0.0018wt%, Ga: 0.023wt%, Hf: 0.015wt%, RE: 0.06wt%, the total amount of other impurities is less than 0.2wt%, and the balance is Al. Among them, RE is industrial pure La-Ce mixed rare earth, which includes 40% La and 60% Ce.

[0179] The preparation method of the heat treatment-free aluminum alloy is as follows:

[0180] Step 1: Prepare the materials according to the alloy composition ratio, calculate the required mass of each raw material, and then preheat and dry each raw material. Set the furnace temperature to 750°C, put the recycled aluminum into the melting furnace, and after the recycled aluminum is melted, add Al-Si master alloy, Al-Cu master alloy, Al-Mn master alloy, Al-Fe master alloy, Al-Ti master alloy, Al-Sr master alloy, Al-V master alloy, Al-Sb master alloy, Al-Hf master alloy and RE rare earth respectively for melting.

[0181] Among them, the Fe content in the recycled aluminum is ≤0.35wt%.

[0182] Step 2: After melting, cool to 720°C, add pure Mg, and use a bell tool to press Mg into the bottom of the melting furnace to prevent Mg from burning on the liquid surface. Use the same method to press Ga wrapped in aluminum foil into the bottom of the melting furnace to prevent Ga from burning on the liquid surface.

[0183] Step 3: After pure Mg and pure Ga are melted, the melt is refined and degassed at 740° C., the amount of refining agent added is 0.2 wt %, and the refining and degassing time is 10 min.

[0184] Step 4: Take samples to test the composition of the casting liquid. If the composition of the casting liquid is qualified, high-pressure die casting is performed to obtain the aluminum alloy without heat treatment.

[0185] Among them, the process parameters of high-pressure die casting are: casting pressure 400 bar, injection speed 6 m / s, vacuum degree 38 mbar, die casting temperature 710°C, and mold temperature 210°C.

[0186] The die-casting mold is a flat mold and a flow mold. Then, tensile test pieces and bending test pieces are taken from the flat mold casting body for tensile performance testing, flow performance testing, bending angle testing, metallographic structure and fracture microscopic analysis.

[0187] Example 10

[0188] This embodiment provides a heat-treatment-free aluminum alloy, which includes the following components in percentage by mass:

[0189] Si: 7.9wt%, Fe: 0.13wt%, Cu: 0.25wt%, Mn: 0.58wt%, Mg: 0.08wt%, Ti: 0.13wt%, Sr: 0.028wt%, V: 0.016wt%, Sb: 0.001wt%, Ga: 0.012wt%, Hf: 0.04wt%, RE: 0.04wt%, the total amount of other impurities is less than 0.2wt%, and the balance is Al. Among them, RE is industrial pure La-Ce-Gd mixed rare earth, which includes 40% La, 50% Ce and 10% Gd.

[0190] The preparation method of the heat treatment-free aluminum alloy is as follows:

[0191] Step 1: Prepare the materials according to the alloy composition ratio, calculate the required mass of each raw material, and then preheat and dry each raw material. Set the furnace temperature to 750°C, put the recycled aluminum into the melting furnace, and after the recycled aluminum is melted, add Al-Si master alloy, Al-Cu master alloy, Al-Mn master alloy, Al-Fe master alloy, Al-Ti master alloy, Al-Sr master alloy, Al-V master alloy, Al-Sb master alloy, Al-Hf master alloy and RE rare earth respectively for melting.

[0192] Among them, the Fe content in the recycled aluminum is ≤0.35wt%.

[0193] Step 2: After melting, cool to 720°C, add pure Mg, and use a bell tool to press Mg into the bottom of the melting furnace to prevent Mg from burning on the liquid surface. Use the same method to press Ga wrapped in aluminum foil into the bottom of the melting furnace to prevent Ga from burning on the liquid surface.

[0194] Step 3: After pure Mg and pure Ga are melted, the melt is refined and degassed at 740° C., the amount of refining agent added is 0.3 wt %, and the refining and degassing time is 10 min.

[0195] Step 4: Take samples to test the composition of the casting liquid. If the composition of the casting liquid is qualified, high-pressure die casting is performed to obtain the aluminum alloy without heat treatment.

[0196] Among them, the process parameters of high-pressure die casting are: casting pressure 450bar, injection speed 5m / s, vacuum degree 33mbar, die casting temperature 700℃, and mold temperature 200℃.

[0197] The die-casting mold is a flat mold and a flow mold. Then, tensile test pieces and bending test pieces are taken from the flat mold casting body for tensile performance testing, flow performance testing, bending angle testing, metallographic structure and fracture microscopic analysis.

[0198] Comparative Example 1

[0199] This comparative example provides an aluminum alloy, which includes the following components in percentage by mass:

[0200] Si: 6.9wt%, Fe: 0.25wt%, Cu: 0.18wt%, Mn: 0.61wt%, Mg: 0.36wt%, Ti: 0.17wt%, Sr: 0.032wt%, V: 0.005wt%, Sb: 0.02wt%, Ga: 0.006wt%, Hf: 0.056wt%, RE: 0.06wt%, the total amount of other impurities is less than 0.2wt%, and the balance is Al. Among them, RE is industrial pure La-Ce mixed rare earth, which includes 40% La and 60% Ce.

[0201] The preparation method is the same as that in Example 3 and will not be described in detail here.

[0202] Comparative Example 2

[0203] This comparative example provides an aluminum alloy, which includes the following components in percentage by mass:

[0204] Si: 6.9wt%, Fe: 0.25wt%, Cu: 0.18wt%, Mn: 0.61wt%, Mg: 0.36wt%, Ti: 0.17wt%, Sr: 0.032wt%, V: 0.016wt%, Sb: 0.0013wt%, Hf: 0.021wt%, RE: 0.06wt%, the total amount of other impurities is less than 0.2wt%, and the balance is Al. Among them, RE is industrial pure La-Ce mixed rare earth, which includes 40% La and 60% Ce.

[0205] The preparation method is the same as that in Example 3 and will not be described in detail here.

[0206] Comparative Example 3

[0207] This comparative example provides an aluminum alloy, which includes the following components in percentage by mass:

[0208] Si: 6.9wt%, Fe: 0.25wt%, Cu: 0.18wt%, Mn: 0.61wt%, Mg: 0.36wt%, Ti: 0.17wt%, Sr: 0.032wt%, V: 0.016wt%, Sb: 0.0013wt%, Ga: 0.016wt%, RE: 0.06wt%, the total amount of other impurities is less than 0.2wt%, and the balance is Al. Among them, RE is industrial pure La-Ce mixed rare earth, which includes 40% La and 60% Ce.

[0209] The preparation method is the same as that in Example 3 and will not be described in detail here.

[0210] Comparative Example 4

[0211] This comparative example provides an aluminum alloy, which includes the following components in percentage by mass:

[0212] Si: 6.9wt%, Fe: 0.25wt%, Cu: 0.18wt%, Mn: 0.61wt%, Mg: 0.36wt%, Ti: 0.17wt%, Sr: 0.032wt%, V: 0.016wt%, Sb: 0.0013wt%, RE: 0.06wt%, the total amount of other impurities is less than 0.2wt%, and the balance is Al. Among them, RE is industrial pure La-Ce mixed rare earth, which includes 40% La and 60% Ce.

[0213] The preparation method is the same as that in Example 3 and will not be described in detail here.

[0214] Comparative Example 5

[0215] This comparative example provides an aluminum alloy, which includes the following components in percentage by mass:

[0216] Si: 6.9wt%, Fe: 0.25wt%, Cu: 0.18wt%, Mn: 0.61wt%, Mg: 0.36wt%, Ti: 0.17wt%, Sr: 0.032wt%, V: 0.016wt%, Sb: 0.0013wt%, the total amount of other impurities is <0.2wt%, and the balance is Al.

[0217] The preparation method is the same as that in Example 3 and will not be described in detail here.

[0218] Comparative Example 6

[0219] This comparative example provides an aluminum alloy, which includes the following components in percentage by mass:

[0220] Si: 7.5wt%, Fe: 0.19wt%, Cu: 0.26wt%, Mn: 0.63wt%, Mg: 0.28wt%, Ti: 0.15wt%, Sr: 0.039wt%, V: 0.07wt%, Sb: 0.0005wt%, Ga: 0.04wt%, Hf: 0.005wt%, RE: 0.1wt%, the total amount of other impurities is less than 0.2wt%, and the balance is Al. Among them, RE is industrial pure La-Ce mixed rare earth, which includes 40% La and 60% Ce.

[0221] The preparation method is the same as that of Example 10 and will not be described again here.

[0222] Comparative Example 7

[0223] This comparative example provides an aluminum alloy, which includes the following components in percentage by mass:

[0224] Si: 7.5wt%, Fe: 0.19wt%, Cu: 0.26wt%, Mn: 0.63wt%, Mg: 0.28wt%, Ti: 0.15wt%, Sr: 0.039wt%, Sb: 0.0056wt%, Ga: 0.023wt%, Hf: 0.036wt%, RE: 0.1wt%, the total amount of other impurities is less than 0.2wt%, and the balance is Al. Among them, RE is industrial pure La-Ce mixed rare earth, which includes 40% La and 60% Ce.

[0225] The preparation method is the same as that of Example 10 and will not be described again here.

[0226] Comparative Example 8

[0227] This comparative example provides an aluminum alloy, which includes the following components in percentage by mass:

[0228] Si: 7.5wt%, Fe: 0.19wt%, Cu: 0.26wt%, Mn: 0.63wt%, Mg: 0.28wt%, Ti: 0.15wt%, Sr: 0.039wt%, V: 0.022wt%, Ga: 0.023wt%, Hf: 0.036wt%, RE: 0.1wt%, the total amount of other impurities is less than 0.2wt%, and the balance is Al. Among them, RE is industrial pure La-Ce mixed rare earth, which includes 40% La and 60% Ce.

[0229] The preparation method is the same as that of Example 10 and will not be described again here.

[0230] Comparative Example 9

[0231] This comparative example provides an aluminum alloy, which includes the following components in percentage by mass:

[0232] Si: 7.5wt%, Fe: 0.19wt%, Cu: 0.26wt%, Mn: 0.63wt%, Mg: 0.28wt%, Ti: 0.15wt%, Sr: 0.039wt%, RE: 0.1wt%, the total amount of other impurities is less than 0.2wt%, and the balance is Al. Among them, RE is industrial pure La-Ce mixed rare earth, which includes 40% La and 60% Ce.

[0233] The preparation method is the same as that of Example 10 and will not be described again here.

[0234] Comparative Example 10

[0235] This comparative example provides an aluminum alloy, which includes the following components in percentage by mass:

[0236] Si: 7.5wt%, Fe: 0.19wt%, Cu: 0.26wt%, Mn: 0.63wt%, Mg: 0.28wt%, Ti: 0.15wt%, Sr: 0.039wt%, the total amount of other impurities is <0.2wt%, and the balance is Al.

[0237] The preparation method is the same as that of Example 10 and will not be described again here.

[0238] The compositions of Examples 1 to 10 and Comparative Examples 1 to 10 can also be found in Table 1 below.

[0239] Table 1

[0240]

[0241]

[0242]

[0243] The performance test results of Examples 1 to 10 and Comparative Examples 1 to 10 are shown in Table 2 below.

[0244] Table 2

[0245]

[0246]

[0247] It can be seen from Table 2 that when Example 3 is compared with Comparative Examples 2 to 5, when Ga, Hf, and RE are not added to the aluminum alloy, the mechanical properties of the aluminum alloy deteriorate and the bending angle decreases. When Example 7 is compared with Comparative Examples 7 to 10, when V, Sb, Ga, Hf, and RE are not added to the aluminum alloy, the tensile strength, yield strength, elongation, and bending angle of the aluminum alloy are all reduced, and the fluidity of the aluminum alloy deteriorates. The mass percentage relationship K of V, Ga, Sb, and Hf in Comparative Example 1 and Comparative Example 6 does not satisfy 1<K<17. At this time, the performance of the aluminum alloy deteriorates, indicating that the mass percentage relationship of V, Ga, Sb, and Hf needs to be strictly controlled within this range. It can be explained that: adding trace elements V, Sb, Ga, Hf, and RE rare earth to the aluminum alloy and adding them to the matrix according to a certain ratio, through the synergistic effect of different elements, can effectively improve the tensile strength, yield strength, elongation, bending angle, and fluidity of the aluminum alloy, and achieve the effect of optimizing the comprehensive performance of the aluminum alloy.

[0248] The aluminum alloy provided in the present application does not stick to the mold during the die casting process, and the fluidity test results are good. The test pieces of the casting body are taken for tensile mechanical property test, bending angle test, metallographic structure and fracture micro-scanning electron microscope analysis. The results show that the aluminum alloy has both high yield strength and high elongation, and the fluidity is similar to that of AlSi 10 The MnMg content is quite high, the bending angle is large, and the material does not crack during riveting. The α-Al grain size in the metallographic structure is small and evenly distributed, the matrix has no coarse pre-crystallized structure, and the aluminum alloy modification effect is good. Figure 2 and Figure 3 It can also be seen that Figure 2 The metallographic structure diagram of the aluminum alloy prepared in Example 5 (200 times), Figure 3 This is the metallographic structure diagram of the aluminum alloy prepared in Example 7 (500 times). Scanning electron microscope fracture micromorphology analysis shows that the dimples are dense and uniform in size, which is a typical ductile fracture, indicating that the material has the characteristics of high strength and high toughness. Figure 4 It can also be seen that Figure 4 This is a scanning electron microscope fracture micromorphology image of the aluminum alloy prepared in Example 3.

[0249] In summary, the aluminum alloy prepared in the present application is suitable for integrated die-casting of large, thin-walled, complexly structured automotive parts that require high strength and high toughness, and the aluminum alloy can be produced 100% using recycled aluminum, which greatly reduces carbon emissions and reduces corporate costs, effectively promoting the goal of lightweighting automobiles and achieving low-carbon sustainable circular production.

[0250] The above description is only for the purpose of facilitating those skilled in the art to understand the technical solution of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A heat treatment-free aluminum alloy, characterized in that: The heat treatment-free aluminum alloy comprises the following components in percentage by mass: Si: 6.1-7.9wt%, Fe: 0.09-0.35wt%, Cu: 0.01-0.3wt%, Mn: 0.45-0.7wt%, Mg: 0.08-0.38wt%, Ti: 0.06-0.18wt%, Sr: 0.016-0.045wt%, V: 0.01-0.05wt%, Sb: 0.001-0.01wt%, Ga: 0.01-0.025wt%, Hf: 0.01-0.04wt%, RE: 0.005-0.11wt%, the total amount of other impurities is ≤0.2wt%, and the balance is Al; Wherein, RE includes at least one of La, Ce and Gd.

2. The heat-treatment-free aluminum alloy according to claim 1, characterized in that: The mass percentages of V, Ga, Sb and Hf satisfy 1< K <17; in, 3. The heat-treatment-free aluminum alloy according to claim 1, characterized in that: The heat treatment-free aluminum alloy comprises the following components in percentage by mass: Si: 6.1~7.0wt%, Fe: 0.15~0.35wt%, Cu: 0.01~0.2wt%, Mn: 0.45~0.7wt%, Mg: 0.28~0.38wt%, Ti: 0.06~0.18wt%, Sr: 0.016~0.033wt%, V: 0.01~0.03wt%, Sb: 0.001~0.01wt%, Ga: 0.01~0.018wt%, Hf: 0.01~0.025wt%, RE: 0.005~0.06wt%, the total amount of other impurities is ≤0.2wt%, and the balance is Al.

4. The heat-treatment-free aluminum alloy according to claim 1, characterized in that: The heat treatment-free aluminum alloy comprises the following components in percentage by mass: Si: 7.0~7.9wt%, Fe: 0.09~0.22wt%, Cu: 0.1~0.3wt%, Mn: 0.45~0.7wt%, Mg: 0.08~0.28wt%, Ti: 0.06~0.18wt%, Sr: 0.033~0.045wt%, V: 0.03~0.05wt%, Sb: 0.001~0.01wt%, Ga: 0.015~0.025wt%, Hf: 0.02~0.04wt%, RE: 0.05~0.11wt%, the total amount of other impurities is ≤0.2wt%, and the balance is Al.

5. The heat-treatment-free aluminum alloy according to claim 1, characterized in that: The heat treatment-free aluminum alloy comprises the following components in percentage by mass: Si: 6.9wt%, Fe: 0.25wt%, Cu: 0.18wt%, Mn: 0.61wt%, Mg: 0.36wt%, Ti: 0.17wt%, Sr: 0.032wt%, V: 0.016wt%, Sb: 0.0013wt%, Ga: 0.016wt%, Hf: 0.021wt%, RE: 0.06wt%, the total amount of other impurities is ≤ 0.2wt%, and the balance is Al; Wherein, RE is industrial pure La-Ce mixed rare earth, and the mixed rare earth includes 40% La and 60% Ce.

6. The heat-treatment-free aluminum alloy according to claim 1, characterized in that: The heat treatment-free aluminum alloy comprises the following components in percentage by mass: Si: 7.5wt%, Fe: 0.19wt%, Cu: 0.26wt%, Mn: 0.63wt%, Mg: 0.28wt%, Ti: 0.15wt%, Sr: 0.039wt%, V: 0.022wt%, Sb: 0.0056wt%, Ga: 0.023wt%, Hf: 0.036wt%, RE: 0.1wt%, the total amount of other impurities is ≤ 0.2wt%, and the balance is Al; Among them, RE is industrial pure La rare earth.

7. The heat-treatment-free aluminum alloy according to claim 1, characterized in that: Al comes from recycled aluminum, and Fe in the recycled aluminum is ≤ 0.35 wt%.

8. A method for preparing a heat-treatment-free aluminum alloy according to any one of claims 1 to 7, characterized in that: The preparation method comprises: Putting the regenerated aluminum into a melting furnace, and after the regenerated aluminum is melted, respectively adding Al-Si master alloy, Al-Cu master alloy, Al-Mn master alloy, Al-Fe master alloy, Al-Ti master alloy, Al-Sr master alloy, Al-V master alloy, Al-Sb master alloy, Al-Hf master alloy and RE rare earth to melt, the temperature of the melting furnace is 750° C.; After melting, the temperature is lowered to 720°C and pure Mg and pure Ga are added; After pure Mg and pure Ga are melted, the melt is refined and degassed at 720-740°C; Take samples to test the composition of the pouring liquid; When the composition of the casting liquid is qualified, high-pressure die casting is performed to obtain the heat-treatment-free aluminum alloy.

9. The preparation method according to claim 8, characterized in that: The high pressure die casting includes the following process parameters: Casting pressure 350 ~ 450 bar, injection speed 3 ~ 6 m / s, vacuum degree <50 mbar, die casting temperature 680 ~ 720 ℃, mold temperature 180 ~ 230 ℃.

10. The preparation method according to claim 8, characterized in that: The content of the refining agent added in the refining and degassing is 0.1-0.6wt%, and the refining and degassing time is 8-13min.

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