Integrated heat-treatment-free aluminum alloy material for vehicle and preparation method thereof

Abstract

The invention discloses an integrated heat-treatment-free aluminum alloy material for a vehicle and a preparation method thereof, and belongs to the technical field of aluminum alloys. Based on the total weight of the aluminum alloy, the aluminum alloy comprises the following components in percentage by mass: 5.5%-7.5% of Si, 0.6%-1.2% of Mg, 0.4%-0.8% of Cu, 0.3%-0.7% of Mn, 0.05%-0.15% of Zr, 0.1%-0.4% of Zn, 0.02%-0.2% of Fe, 0.02%-0.1% of Mo, 0.05%-0.1% of Ge, 0.005%-0.05% of RE and the balance of Al and inevitable impurities. Through component optimization and microstructure regulation and control, the integrated heat-treatment-free aluminum alloy material for the vehicle is obtained, and the aluminum alloy material has high strength and excellent plasticity and toughness, corrosion resistance and flow formability, does not need heat treatment and has good mechanical properties in a cast state.

Description

Technical Field

[0001] The present invention relates to the technical field of aluminum alloys, and in particular to an integrated heat-treatment-free aluminum alloy material for vehicles and a preparation method thereof. Background Art

[0002] With the rapid development of the new energy vehicle industry, lightweighting of automobiles has become an important trend. Aluminum alloys are widely used in vehicle body structures, engines and various accessories due to their excellent lightweight, corrosion resistance and good processing properties.

[0003] Lightweighting in automobiles places higher demands on the toughness (e.g., tensile strength ≥ 200 MPa, elongation ≥ 10%), impact resistance, and formability of aluminum alloys. Existing automotive aluminum alloys (e.g., 6xxx and 7xxx series) require complex heat treatment (T6 / T7) or hot forming processes to achieve high performance, but these processes suffer from high energy consumption, high rebound, and susceptibility to oxidation. Traditional cast aluminum alloys (e.g., Al-Si series) lack sufficient strength or toughness to meet collision energy absorption requirements.

[0004] Based on this, the present invention obtains an integrated heat-treatment-free aluminum alloy material for automobiles through composition optimization and microstructure regulation. The aluminum alloy material has high strength and excellent plasticity, toughness, corrosion resistance, and flow formability, and does not require heat treatment. It has good mechanical properties in the cast state, thereby meeting the needs of existing automotive thin-walled structural parts. Summary of the Invention

[0005] In response to the problems existing in the prior art, the purpose of the present invention is to provide an integrated automotive aluminum alloy material that does not require heat treatment and a preparation method thereof. The aluminum alloy material has high strength and excellent plasticity, toughness, corrosion resistance, and flow formability, and does not require heat treatment, thereby reducing part deformation. It also has good mechanical properties in the cast state, meeting the needs of existing integrated automotive thin-walled structural parts.

[0006] According to a first aspect of the present invention, the present invention provides an integrated heat-treatment-free aluminum alloy material for a vehicle, which comprises the following components in percentage by mass, based on the total weight of the aluminum alloy: Si 5.5-7.5%, Mg 0.6-1.2%, Cu 0.4-0.8%, Mn 0.3-0.7%, Zr 0.05-0.15%, Zn 0.1-0.4%, Fe 0.02-0.2%, Mo 0.02-0.1%, Ge 0.05-0.1%, RE 0.005-0.05%, and the balance being Al and unavoidable impurities.

[0007] As a preferred embodiment of the present invention, based on the total weight of the aluminum alloy, it includes the following components in percentage by mass: Si 6.0-7.0%, Mg 0.9-1.2%, Cu 0.6-0.8%, Mn 0.3-0.5%, Zr 0.10-0.13%, Zn 0.2-0.3%, Fe 0.02-0.1%, Mo 0.07-0.1%, Ge 0.08-0.1%, RE 0.02-0.04%, and the balance is Al and unavoidable impurities.

[0008] As a preferred solution of the present invention, the RE element is La and / or Nd.

[0009] As a preferred solution of the present invention, the content of other inevitable impurity elements in the heat treatment-free aluminum alloy material does not exceed 0.2%.

[0010] As a preferred solution of the present invention, the tensile strength of the heat-treatment-free aluminum alloy is not less than 280 MPa, the yield strength is not less than 160 MPa, and the elongation is not less than 12%.

[0011] According to a second aspect of the present invention, the present invention further provides a method for preparing the integrated heat-treatment-free aluminum alloy material for automobiles as described in any one of the first aspects of the present invention, comprising the following steps:

[0012] (1) Add Al ingots and Si ingots to a smelting furnace, heat to 720-740°C, and add Al-Fe master alloy, Al-Cu master alloy, and Al-Mn master alloy after all are melted. After all are melted, cool to 680-700°C and let stand at this temperature for 10-15 minutes.

[0013] (2) Using inert gas as a carrier, spray a powder refining agent equivalent to 0.1-0.3% of the melt mass from the bottom of the smelting furnace to perform refining and slag removal;

[0014] (3) After refining and slag removal is completed, the melt temperature is raised to 760-780°C, and Mg ingots, Zn ingots, Al-Zr intermediate alloys, and Al-Mo intermediate alloys are added to the melting furnace for melting. After the raw materials are completely melted, electromagnetic stirring is performed;

[0015] (4) After stirring, the melt temperature is controlled at 730-750° C., Al-RE master alloy is added and pressed into the bottom for melting. After all the raw materials are melted, Al-Ge master alloy is added for melting. After the raw materials are completely melted, 0.004-0.006% segregation improver by mass of the melt is added for electromagnetic stirring, and the temperature is kept for 10-15 minutes to obtain a melt;

[0016] (5) introducing argon gas mixed with a refining agent into the melt of step (4) to perform degassing and refining;

[0017] (6) filtering the degassed and refined melt online;

[0018] (7) The filtered melt is die-casted to obtain the die-cast aluminum alloy.

[0019] As a preferred embodiment of the present invention, the powder refining agent in step (2) is a mixture of NaCl, KCl, K2TiF6, and K2BF6 in a mass ratio of 3:2:2:1.

[0020] As a preferred embodiment of the present invention, the preparation method of the segregation improving agent in step (4) is:

[0021] According to the mass ratio, 4-6g ZrO2, 1-2g CaO and 3-5g SrO are mixed together and ground. The ground mixture is added to 0.3mol / L citric acid and heated to 500-550℃ and stirred for 20-30min. The product is then filtered, washed and dried with anhydrous ethanol, and then ground to 700-800 mesh to obtain the desired segregation improver.

[0022] As a preferred embodiment of the present invention, the online filtration in step (6) is performed using a bipolar filter plate, and the maximum inclusion size of the melt after filtration is no greater than 10 μm.

[0023] As a preferred embodiment of the present invention, the die-casting conditions in step (7) include: the melt temperature in the holding furnace is controlled at 650-670°C; the mold temperature controller is set at 210-230°C; the low-speed injection speed of the die-casting machine is 0.08-0.15m / s, and the high-speed injection speed of the die-casting machine is 3.5-4.5m / s; the die-casting pressure is 70-90MPa; and the vacuum degree in the mold cavity is not greater than 7kPa.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The present invention provides an integrated heat-treatment-free aluminum alloy material for vehicles. By controlling the contents of elements such as Si, Mg, Cu, Mn, Zr, Zn, Fe, Mo, Ge, and RE in the aluminum alloy, through composition optimization and microstructure regulation, and without the need for heat treatment, the defects caused by the die-casting process are effectively reduced, and the obtained aluminum alloy material has high toughness and good thermal cracking resistance in the cast state, thereby improving its comprehensive mechanical properties. Compared with existing die-cast aluminum alloy materials, the aluminum alloy material provided by the present invention has better yield strength (not less than 280 MPa), tensile strength (not less than 160 MPa), and elongation (not less than 12%), as well as better casting performance. DETAILED DESCRIPTION

[0026] The specific embodiments of the present invention will be further described below in conjunction with examples. The following examples are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0027] The present application discloses an integrated heat-treatment-free aluminum alloy material for automobiles and a preparation method thereof. This aluminum alloy material has high strength and toughness and good thermal crack resistance in the cast state, does not require heat treatment, reduces part deformation, and effectively solves the problem of insufficient strength or toughness of traditional cast aluminum alloys (such as Al-Si series).

[0028] An embodiment of the present invention provides an integrated heat-treatment-free aluminum alloy material for a vehicle, which includes the following element components in the following mass percentages: Si 5.5-7.5%, Mg 0.6-1.2%, Cu 0.4-0.8%, Mn 0.3-0.7%, Zr 0.05-0.15%, Zn 0.1-0.4%, Fe 0.02-0.2%, Mo 0.02-0.1%, Ge 0.05-0.1%, RE 0.005-0.05%, and the balance is Al and unavoidable impurities.

[0029] Regarding the aluminum alloy materials mentioned above, the role of each element component therein is first described.

[0030] In this embodiment, the mass percentage of Si element is 5.5-7.5%, which includes but is not limited to the following point values and the interval range formed by any two point values: 5.5%, 5.6%, 5.7%, 5.8%, 5.9%, 6.0%, 6.1%, 6.2%, 6.3%, 6.4%, 6.5%, 6.6%, 6.7%, 6.8%, 6.9%, 7.0%, 7.1%, 7.2%, 7.3%, 7.4%, 7.5%, etc.

[0031] The element Si not only increases the strength of aluminum alloys but also ensures their casting fluidity. When the Si content is less than 5.5%, the amount of silicon dissolved in the solid solution decreases, which can reduce the aluminum alloy's high-temperature moldability, increase shrinkage, increase the tendency to hot cracking, and reduce strength and elongation. In contrast, when the Si content exceeds 7.5%, the aluminum alloy's corrosion resistance and compressive strength are significantly reduced.

[0032] In this embodiment, the mass percentage of Mg element is 0.6-1.2%, which includes but is not limited to the following point values and the interval range formed by any two point values: 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, etc.

[0033] Under forming conditions, Mg can increase the strength of the matrix and precipitate a second phase (such as Mg2Si) in the eutectic region, thereby enhancing the strength of the aluminum alloy. When the magnesium content is less than 0.6%, Mg's strengthening effect on the aluminum alloy material is insufficient, and the performance improvement is poor. When the Mg content exceeds 1.2%, the solubility of Mg itself in the aluminum alloy is relatively limited, and the precipitation rate is not ideal. Adding too much magnesium will form an excess phase between the grains, which will reduce the strength at the grain boundaries and make the aluminum alloy brittle.

[0034] In this embodiment, the mass percentage of Cu element is 0.4-0.8%, which includes but is not limited to the following point values and the interval range formed by any two point values: 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, etc.

[0035] Under forming conditions, the Cu element can precipitate a strengthening phase (such as Al2Cu) in the eutectic region, enhancing the strength of the aluminum alloy. It can also improve the casting fluidity of the aluminum alloy material, compensating for the reduced fluidity caused by the low silicon content. When the Cu content is less than 0.4%, the tensile strength and corrosion resistance of the aluminum alloy are insufficient; when the Cu content exceeds 0.8%, coarse defects in the intermetallic compounds will appear, which greatly reduces the corrosion resistance of the aluminum alloy.

[0036] In this embodiment, the mass percentage of the Mn element is 0.3-0.7%, which includes but is not limited to the following point values and the interval range formed by any two point values: 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, etc.

[0037] The addition of Mn helps to improve the corrosion resistance of aluminum alloys and is distributed in the aluminum matrix in the form of fine Al-Mn intermetallic compounds. However, when the manganese content is less than 0.3%, the corrosion resistance of the aluminum alloy may not achieve the expected effect; when the manganese content exceeds 0.7%, the corrosion resistance of the aluminum alloy is not significantly improved and is not economically feasible.

[0038] In this embodiment, the mass percentage of the Zr element is 0.05-0.15%, which includes but is not limited to the following point values and the interval range formed by any two point values: 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.10%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, etc.

[0039] The addition of Zr can form Al3Zr coarse phase, β′(Al3Zr) metastable phase and Al3Zr(DO 23 ) equilibrium phase, which can improve the strength, toughness and corrosion resistance of aluminum alloy materials. In addition, ZrAl3 formed in the matrix can hinder the recrystallization process, thereby achieving the purpose of grain refinement.

[0040] In this embodiment, the mass percentage of the Zn element is 0.1-0.4%, which includes but is not limited to the following point values and the interval range formed by any two point values: 0.1%, 0.2%, 0.3%, 0.4%, etc.

[0041] The Zn element is enriched in the Al-Si-Mn-Mg-Cu phase and the Fe-containing phase surface, inhibiting its growth and reducing its size, thereby significantly improving the cast properties of the aluminum alloy material. Moreover, during the aging process, the solid solubility of the Zn element in the α-Al phase increases, which has a solid solution strengthening effect, which is beneficial to increase the strength of the aluminum alloy material.

[0042] In this embodiment, the mass percentage of Fe element is 0.02-0.2%, which includes but is not limited to the following point values and the interval range formed by any two point values: 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.10%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, 0.20%, etc.

[0043] During solidification, Fe easily forms a needle-like β-Fe phase with elements like Al and Si. This can lead to stress concentration during stress loading, cracking the matrix and degrading the performance of the aluminum alloy. When the Fe content is less than 0.02%, the effect of grain refinement and improving the mechanical strength of the aluminum alloy is minimal. Conversely, when the Fe content exceeds 0.2%, the intermetallic compounds become coarse, significantly reducing the corrosion resistance of the aluminum alloy.

[0044] In this embodiment, the mass percentage of Mo element is 0.02-0.1%, which includes but is not limited to the following point values and the interval range formed by any two point values: 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.10%, etc.

[0045] Mo can be combined with Zr and Mn elements in aluminum alloy materials to inhibit the formation of needle-shaped or flaky β iron-rich phases and promote the formation of Chinese character-shaped or skeleton-shaped α iron-rich phases. The addition of Mo can also refine α dendrites and eutectic silicon in aluminum alloys, improve the overall microstructure, and thus improve the toughness of aluminum alloy materials.

[0046] In this embodiment, the mass percentage of Ge element is 0.05-0.1%, which includes but is not limited to the following point values and the interval range formed by any two point values: 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.10%, etc.

[0047] The Ge element plays the role of a heterogeneous nucleation point, which is beneficial to increasing the nucleation of primary Al grains. Moreover, Ge can smoothly form a second phase with other elements and refine the grains at the same time, ultimately achieving the purpose of improving the strength and toughness of the aluminum alloy material.

[0048] In this embodiment, the mass percentage of the RE element is 0.005-0.05%, which includes but is not limited to the following point values and the interval range formed by any two point values: 0.005%, 0.006%, 0.007%, 0.008%, 0.009%, 0.01%, 0.02%, 0.03%, 0.03%, 0.04%, 0.05%, etc.

[0049] RE elements act as heterogeneous nucleation points, thereby increasing the nucleation of primary (Al) grains, achieving grain refinement, and achieving the purpose of improving the strength and toughness of aluminum alloy materials.

[0050] RE can optimize the microstructure of aluminum alloys, stabilize the grain boundaries, avoid discontinuous distribution of grain boundaries, increase the nucleation of primary (Al) grains, achieve grain refinement, and thus improve the strength and toughness of aluminum alloys.

[0051] In summary, this application effectively improves the strength and toughness of a heat-treatment-free aluminum alloy by adding specific amounts of Si, Mg, Cu, Mn, Zr, Zn, Fe, Mo, Ge, and RE to the heat-treatment-free aluminum alloy material through composition optimization and microstructure control. This also provides the heat-treatment-free aluminum alloy with excellent castability, fluidity, and thermal cracking resistance, making it suitable for large-scale integrated die casting. Specifically, the heat-treatment-free aluminum alloy can simultaneously achieve a tensile strength of no less than 280 MPa, a yield strength of no less than 160 MPa, and an elongation of no less than 12%.

[0052] The embodiments of the present application are described in detail below. It should be noted that the embodiments described below are exemplary and are only used to explain the present application, and should not be understood as limiting the present application.

[0053] Example 1

[0054] A vehicle-use integrated heat-treatment-free aluminum alloy material comprises, based on the total weight of the aluminum alloy, Si, Mg, Cu, Mn, Zr, Zn, Fe, Mo, Ge, and RE (La and Nd having a mass ratio of 1:1), with specific contents as shown in Table 1. The remainder is Al and unavoidable impurities such as P, S, and O, and the total impurity content is ≤0.2%.

[0055] The method for preparing the integrated heat treatment-free aluminum alloy material for vehicles comprises the following steps:

[0056] (1) Add Al ingots and Si ingots to a melting furnace, heat to 730°C, and add Al-Fe master alloy, Al-Cu master alloy, and Al-Mn master alloy after all are melted. After all are melted, cool to 690°C and let stand at this temperature for 13 minutes.

[0057] (2) Using inert gas as a carrier, a powder refining agent equivalent to 0.2% of the melt mass is sprayed from the bottom of the smelting furnace to perform refining and slag removal;

[0058] (3) After refining and slag removal is completed, the melt temperature is raised to 770°C, and Mg ingots, Zn ingots, Al-Zr intermediate alloys, and Al-Mo intermediate alloys are added to the melting furnace for melting. After the raw materials are completely melted, electromagnetic stirring is performed;

[0059] (4) After stirring, the melt temperature is controlled at 740°C, Al-RE master alloy is added, and it is pressed into the bottom for melting. After all the raw materials are melted, Al-Ge master alloy is added for melting. After the raw materials are completely melted, 0.005% segregation improver by mass of the melt is added for electromagnetic stirring, and the temperature is kept for 12 minutes to obtain a melt;

[0060] (5) introducing argon gas mixed with a refining agent into the melt of step (4) to perform degassing and refining;

[0061] (6) filtering the degassed and refined melt online;

[0062] (7) The filtered melt is die-casted to obtain the die-cast aluminum alloy.

[0063] Wherein, the powder refining agent in step (2) is a mixture of NaCl, KCl, K2TiF6, and K2BF6 in a mass ratio of 3:2:2:1.

[0064] The preparation method of the segregation improving agent in step (4) is:

[0065] According to the mass ratio, 4-6g ZrO2, 1-2g CaO and 3-5g SrO are mixed together and ground. The ground mixture is added to 0.3mol / L citric acid and heated to 500-550℃ and stirred for 20-30min. The product is then filtered, washed and dried with anhydrous ethanol, and then ground to 700-800 mesh to obtain the desired segregation improver.

[0066] The online filtration in step (6) is performed using a bipolar filter plate, and the maximum inclusion size of the melt after filtration is no greater than 10 μm.

[0067] The die-casting conditions in step (7) include: the melt temperature in the holding furnace is controlled at 660°C; the mold temperature controller is set at 220°C; the low-speed injection speed of the die-casting machine is 0.11m / s, and the high-speed injection speed of the die-casting machine is 4m / s; the die-casting pressure is 80MPa; and the vacuum degree in the mold cavity is not greater than 7kPa.

[0068] Example 2

[0069] The contents of Si, Mg, Cu, Mn, Zr, Zn, Fe, Mo, Ge, and RE (La and Nd) in the integrated heat-treatment-free aluminum alloy material for automobiles in this embodiment are shown in Table 1. Other conditions are the same as those in Example 1, and the preparation method of the aluminum alloy material in this embodiment is the same as that in Example 1.

[0070] Example 3

[0071] The contents of Si, Mg, Cu, Mn, Zr, Zn, Fe, Mo, Ge, and RE (La and Nd) in the integrated heat-treatment-free aluminum alloy material for automobiles in this embodiment are shown in Table 1. Other conditions are the same as those in Example 1, and the preparation method of the aluminum alloy material in this embodiment is the same as that in Example 1.

[0072] Example 4

[0073] The contents of Si, Mg, Cu, Mn, Zr, Zn, Fe, Mo, Ge, and RE (La) in the integrated heat-treatment-free aluminum alloy material for automobiles in this embodiment are shown in Table 1. Other conditions are the same as those in Example 1, and the preparation method of the aluminum alloy material in this embodiment is the same as that in Example 1.

[0074] Example 5

[0075] The contents of Si, Mg, Cu, Mn, Zr, Zn, Fe, Mo, Ge, and RE (Nd) in the integrated heat-treatment-free aluminum alloy material for automobiles in this embodiment are shown in Table 1. Other conditions are the same as those in Example 1, and the preparation method of the aluminum alloy material in this embodiment is the same as that in Example 1.

[0076] Example 6

[0077] The contents of Si, Mg, Cu, Mn, Zr, Zn, Fe, Mo, Ge, and RE (La and Nd) in the integrated heat-treatment-free aluminum alloy material for automobiles in this embodiment are shown in Table 1. Other conditions are the same as those in Example 1, and the preparation method of the aluminum alloy material in this embodiment is the same as that in Example 1.

[0078] Example 7

[0079] The contents of Si, Mg, Cu, Mn, Zr, Zn, Fe, Mo, Ge, and RE (La and Nd) in the integrated heat-treatment-free aluminum alloy material for automobiles in this embodiment are shown in Table 1. Other conditions are the same as those in Example 1, and the preparation method of the aluminum alloy material in this embodiment is the same as that in Example 1.

[0080] Example 8

[0081] The contents of Si, Mg, Cu, Mn, Zr, Zn, Fe, Mo, Ge, and RE (La and Nd) in the integrated heat-treatment-free aluminum alloy material for automobiles in this embodiment are shown in Table 1. Other conditions are the same as those in Example 1, and the preparation method of the aluminum alloy material in this embodiment is the same as that in Example 1.

[0082] Example 9

[0083] The contents of Si, Mg, Cu, Mn, Zr, Zn, Fe, Mo, Ge, and RE (La and Nd) in the integrated heat-treatment-free aluminum alloy material for automobiles in this embodiment are shown in Table 1. Other conditions are the same as those in Example 1, and the preparation method of the aluminum alloy material in this embodiment is the same as that in Example 1.

[0084] Example 10

[0085] The contents of Si, Mg, Cu, Mn, Zr, Zn, Fe, Mo, Ge, and RE (La and Nd) in the integrated heat-treatment-free aluminum alloy material for automobiles in this embodiment are shown in Table 1. Other conditions are the same as those in Example 1, and the preparation method of the aluminum alloy material in this embodiment is the same as that in Example 1.

[0086] Example 11

[0087] The contents of Si, Mg, Cu, Mn, Zr, Zn, Fe, Mo, Ge, and RE (La and Nd) in the integrated heat-treatment-free aluminum alloy material for automobiles in this embodiment are shown in Table 1. Other conditions are the same as those in Example 1, and the preparation method of the aluminum alloy material in this embodiment is the same as that in Example 1.

[0088] Comparative Example 1

[0089] The contents of Si, Mg, Cu, Mn, Zr, Zn, Fe, Mo, Ge, and RE (La and Nd) in the integrated heat-treatment-free aluminum alloy material for automobiles of the control example are shown in Table 2. Other conditions are the same as those in Example 1, and the preparation method of the aluminum alloy material of the control example is the same as that in Example 1.

[0090] Comparative Example 2

[0091] The contents of Si, Mg, Cu, Mn, Zr, Zn, Fe, Mo, Ge, and RE (La and Nd) in the integrated heat-treatment-free aluminum alloy material for automobiles of the control example are shown in Table 2. Other conditions are the same as those in Example 1, and the preparation method of the aluminum alloy material of the control example is the same as that in Example 1.

[0092] Comparative Example 3

[0093] The contents of Si, Mg, Cu, Mn, Zr, Zn, Fe, Mo, Ge, and RE (La and Nd) in the integrated heat-treatment-free aluminum alloy material for automobiles of the control example are shown in Table 2. Other conditions are the same as those in Example 1, and the preparation method of the aluminum alloy material of the control example is the same as that in Example 1.

[0094] Comparative Example 4

[0095] The contents of Si, Mg, Cu, Mn, Zr, Zn, Fe, Mo, Ge, and RE (La and Nd) in the integrated heat-treatment-free aluminum alloy material for automobiles of the control example are shown in Table 2. Other conditions are the same as those in Example 1, and the preparation method of the aluminum alloy material of the control example is the same as that in Example 1.

[0096] Comparative Example 5

[0097] The contents of Si, Mg, Cu, Mn, Zr, Zn, Fe, Mo, Ge, and RE (La and Nd) in the integrated heat-treatment-free aluminum alloy material for automobiles of the control example are shown in Table 2. Other conditions are the same as those in Example 1, and the preparation method of the aluminum alloy material of the control example is the same as that in Example 1.

[0098] Comparative Example 6

[0099] The contents of Si, Mg, Cu, Mn, Zr, Zn, Fe, Mo, Ge, and RE (La and Nd) in the integrated heat-treatment-free aluminum alloy material for automobiles of the control example are shown in Table 2. Other conditions are the same as those in Example 1, and the preparation method of the aluminum alloy material of the control example is the same as that in Example 1.

[0100] Comparative Example 7

[0101] The contents of Si, Mg, Cu, Mn, Zr, Zn, Fe, Mo, Ge, and RE (La and Nd) in the integrated heat-treatment-free aluminum alloy material for automobiles of the control example are shown in Table 2. Other conditions are the same as those in Example 1, and the preparation method of the aluminum alloy material of the control example is the same as that in Example 1.

[0102] Comparative Example 8

[0103] The contents of Si, Mg, Cu, Mn, Zr, Zn, Fe, Mo, Ge, and RE (La and Nd) in the integrated heat-treatment-free aluminum alloy material for automobiles of the control example are shown in Table 2. Other conditions are the same as those in Example 1, and the preparation method of the aluminum alloy material of the control example is the same as that in Example 1.

[0104] Comparative Example 9

[0105] The contents of Si, Mg, Cu, Mn, Zr, Zn, Fe, Mo, Ge, and RE (La and Nd) in the integrated heat-treatment-free aluminum alloy material for automobiles of the control example are shown in Table 2. Other conditions are the same as those in Example 1, and the preparation method of the aluminum alloy material of the control example is the same as that in Example 1.

[0106] Comparative Example 10

[0107] The contents of Si, Mg, Cu, Mn, Zr, Zn, Fe, Mo, Ge, and RE (La and Nd) in the integrated heat-treatment-free aluminum alloy material for automobiles of the control example are shown in Table 2. Other conditions are the same as those in Example 1, and the preparation method of the aluminum alloy material of the control example is the same as that in Example 1.

[0108] Comparative Example 11

[0109] The contents of Si, Mg, Cu, Mn, Zr, Zn, Fe, Mo, Ge, and RE (La and Nd) in the integrated heat-treatment-free aluminum alloy material for automobiles of the control example are shown in Table 2. Other conditions are the same as those in Example 1, and the preparation method of the aluminum alloy material of the control example is the same as that in Example 1.

[0110] Table 1. Element composition and proportions of heat-treatment-free aluminum alloy materials of Examples 1-11:

[0111] project Si Mg Cu Mn Zr Zn Fe Mo Ge RE Example 1 5.5 0.8 0.4 0.5 0.05 0.2 0.02 0.06 0.07 0.02 Example 2 6.5 0.8 0.4 0.5 0.05 0.2 0.02 0.06 0.07 0.02 Example 3 7.5 0.8 0.4 0.5 0.05 0.2 0.02 0.06 0.07 0.02 Example 4 6.5 0.8 0.4 0.3 0.05 0.2 0.02 0.06 0.07 0.02 Example 5 6.5 0.8 0.4 0.7 0.05 0.2 0.02 0.06 0.07 0.02 Example 6 6.5 0.6 0.4 0.5 0.05 0.2 0.02 0.06 0.07 0.02 Example 7 6.5 1.2 0.4 0.5 0.05 0.2 0.02 0.06 0.07 0.02 Example 8 6.5 0.8 0.4 0.5 0.10 0.2 0.02 0.06 0.07 0.02 Example 9 6.5 0.8 0.4 0.5 0.15 0.2 0.02 0.06 0.07 0.02 Example 10 6.5 0.8 0.4 0.5 0.05 0.2 0.02 0.06 0.07 0.005 Example 11 6.5 0.8 0.4 0.5 0.05 0.2 0.02 0.06 0.07 0.05

[0112] Table 2. Element composition and proportion of heat-treatment-free aluminum alloy materials of comparative examples 1-11:

[0113]

[0114]

[0115] Mechanical properties tests were performed on the heat-treatment-free aluminum alloy materials of Examples 1-11 and Comparative Examples 1-11.

[0116] According to GB / T228.1-2021 "Tensile Tests on Metallic Materials - Part 1: Room Temperature Test Methods", the tensile strength of the aluminum alloy materials obtained in Examples 1-11 and Comparative Examples 1-11 was tested. The test results are shown in Table 3.

[0117] According to GB / T228.1-2021 "Tensile testing of metallic materials - Part 1: Room temperature test methods", the yield strength of the heat-treatment-free aluminum alloy materials obtained in Examples 1-11 and Comparative Examples 1-11 was tested. The test results are shown in Table 3.

[0118] According to GB / T228.1-2021 "Tensile Test of Metallic Materials Part 1: Room Temperature Test Method", the elongation of the heat-treatment-free aluminum alloy materials obtained in Examples 1-11 and Control Examples 1-11 was tested, and the test results are shown in Table 3.

[0119] The yield strength, tensile strength and elongation are tested according to the metal material tensile mechanical properties test standard: GB / 228. The mechanical properties test results of Examples 1-11 and Comparative Examples 1-11 are shown in Table 3.

[0120] Table 3. Mechanical properties of Examples 1-11 and Comparative Examples 1-11:

[0121]

[0122]

[0123] The statistical test results in Table 3 show that, through composition optimization and microstructure control, the present invention can achieve a tensile strength of not less than 280 MPa, a yield strength of not less than 160 MPa, and an elongation of not less than 12% for the heat-treatment-free aluminum alloy, thereby meeting the requirements for integrated thin-walled structural parts for vehicles.

[0124] From the comparison between Example 1 and Control Example 1, it can be seen that the Si content in Control Example 1 is 5.5%, which is lower than the lower limit specified in the embodiments of the present invention, resulting in low yield strength and tensile strength of the heat-treatment-free aluminum alloy, which does not meet the above qualification standards.

[0125] From the comparison between Example 1 and Control Example 2, the Si content in Control Example 2 is 7.5%, which is higher than the upper limit specified in the embodiments of the present invention, resulting in a lower bending angle of the aluminum alloy material, which does not meet the above qualification standards, indicating that the toughness of the aluminum alloy material is poor.

[0126] From the comparison between Example 4 and Control Example 3, it can be seen that the Mn content in Control Example 3 is 0.7%, which is higher than the upper limit specified in the embodiments of the present invention, resulting in lower elongation and bending angle of the aluminum alloy material, which does not meet the above qualification standards, indicating that the plastic toughness of the aluminum alloy material is poor.

[0127] From the comparison between Example 6 and Control Example 4, it can be seen that the Mg content in Control Example 4 is 1.2%, which is higher than the upper limit specified in the embodiments of the present invention, resulting in lower elongation and bending angle of the aluminum alloy material, which does not meet the above qualification standards, indicating that the plastic toughness of the aluminum alloy material is poor.

[0128] From the comparison between Example 8 and Control Example 5, it can be seen that the Zr content in Control Example 5 is 0, which is lower than the lower limit specified in the embodiments of the present invention, resulting in low yield strength and tensile strength of the aluminum alloy material, which does not meet the above qualification standards.

[0129] From the comparison between Example 9 and Control Example 6, it can be seen that the Zr content in Control Example 6 is 0.15%, which is higher than the upper limit specified in the embodiments of the present invention, resulting in lower yield strength and tensile strength of the aluminum alloy material, which does not meet the above qualification standards.

[0130] From the comparison between Example 10 and Control Example 7, it can be seen that the RE content in Control Example 7 is 0, which is lower than the lower limit specified in the embodiments of the present invention, resulting in low yield strength and tensile strength of the aluminum alloy material, which does not meet the above qualification standards.

[0131] From the comparison between Example 11 and Control Example 8, the RE content in Control Example 8 is 0.10, which is higher than the upper limit specified in the embodiments of the present invention, resulting in lower elongation and bending angle of the aluminum alloy material, which does not meet the above qualification standards, indicating that the plastic toughness of the die-cast aluminum alloy is poor.

[0132] From the comparison between Example 11 and Control Example 9, it can be seen that the content of Fe element in Control Example 9 is 0.3%, which is higher than the upper limit specified in the embodiments of the present invention, resulting in lower elongation and bending angle of the aluminum alloy material, which does not meet the above qualification standards, indicating that the plastic toughness of the aluminum alloy material is poor.

[0133] From the comparison between Example 11 and Control Example 10, it can be seen that the content of Ge element in Control Example 10 is 0, which is lower than the lower limit specified in the embodiments of the present invention, resulting in lower elongation and bending angle of the aluminum alloy material, which does not meet the above qualification standards, indicating that the plastic toughness of the aluminum alloy material is poor.

[0134] From the comparison between Example 11 and Control Example 11, it can be seen that the content of Ge element in Control Example 11 is 0.15%, which is higher than the upper limit specified in the embodiments of the present invention, resulting in lower elongation and bending angle of the aluminum alloy material, which does not meet the above qualification standards, indicating that the plastic toughness of the aluminum alloy material is poor.

[0135] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein with equivalents. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. An integrated heat-treatment-free aluminum alloy material for automobiles, characterized in that: Based on the total weight of the aluminum alloy, the aluminum alloy includes the following components in percentage by mass: Si 5.5-7.5%, Mg 0.6-1.2%, Cu 0.4-0.8%, Mn 0.3-0.7%, Zr 0.05-0.15%, Zn 0.1-0.4%, Fe 0.02-0.2%, Mo 0.02-0.1%, Ge 0.05-0.1%, RE 0.005-0.05%, and the balance is Al and unavoidable impurities.

2. The integrated heat-treatment-free aluminum alloy material for vehicles according to claim 1, characterized in that: Based on the total weight of the aluminum alloy, the aluminum alloy includes the following components in percentage by mass: Si 6.0-7.0%, Mg 0.9-1.2%, Cu 0.6-0.8%, Mn 0.3-0.5%, Zr 0.10-0.13%, Zn 0.2-0.3%, Fe 0.02-0.1%, Mo 0.07-0.1%, Ge 0.08-0.1%, RE 0.02-0.04%, and the balance is Al and unavoidable impurities.

3. The integrated heat-treatment-free aluminum alloy material for vehicles according to claim 1, characterized in that: The RE element is La and / or Nd.

4. The integrated heat-treatment-free aluminum alloy material for vehicles according to claim 1, characterized in that: The content of other inevitable impurity elements in the heat treatment-free aluminum alloy material does not exceed 0.2%.

5. The integrated heat-treatment-free aluminum alloy material for vehicles according to any one of claims 1 to 4, characterized in that: The tensile strength of the heat-treatment-free aluminum alloy is not less than 280 MPa, the yield strength is not less than 160 MPa, and the elongation is not less than 12%.

6. A method for preparing an integrated heat-treatment-free aluminum alloy material for a vehicle according to any one of claims 1 to 5, characterized in that: The following steps are involved: (1) Add Al ingots and Si ingots to a smelting furnace, heat to 720-740°C, and add Al-Fe master alloy, Al-Cu master alloy, and Al-Mn master alloy after all are melted. After all are melted, cool to 680-700°C and let stand at this temperature for 10-15 minutes. (2) Using inert gas as a carrier, spray a powder refining agent equivalent to 0.1-0.3% of the melt mass from the bottom of the smelting furnace to perform refining and slag removal; (3) After refining and slag removal is completed, the melt temperature is raised to 760-780°C, and Mg ingots, Zn ingots, Al-Zr intermediate alloys, and Al-Mo intermediate alloys are added to the melting furnace for melting. After the raw materials are completely melted, electromagnetic stirring is performed; (4) After stirring, the melt temperature is controlled at 730-750° C., Al-RE master alloy is added and pressed into the bottom for melting. After all the raw materials are melted, Al-Ge master alloy is added for melting. After the raw materials are completely melted, 0.004-0.006% segregation improver by mass of the melt is added for electromagnetic stirring, and the temperature is kept for 10-15 minutes to obtain a melt; (5) introducing argon gas mixed with a refining agent into the melt of step (4) to perform degassing and refining; (6) filtering the degassed and refined melt online; (7) The filtered melt is die-casted to obtain the die-cast aluminum alloy.

7. The method for preparing an integrated heat-treatment-free aluminum alloy material for vehicles according to claim 6, characterized in that: The powder refining agent in step (2) is a mixture of NaCl, KCl, K2TiF6, and K2BF6 in a mass ratio of 3:2:2:

1.

8. The method for preparing an integrated heat-treatment-free aluminum alloy material for vehicles according to claim 6, characterized in that: The preparation method of the segregation improving agent in step (4) is: According to the mass ratio, 4-6g ZrO2, 1-2g CaO and 3-5g SrO are mixed together and ground. The ground mixture is added to 0.3mol / L citric acid and heated to 500-550℃ and stirred for 20-30min. The product is then filtered, washed and dried with anhydrous ethanol, and then ground to 700-800 mesh to obtain the desired segregation improver.

9. The method for preparing an integrated heat-treatment-free aluminum alloy material for vehicles according to claim 6, characterized in that: The online filtration in step (6) is performed using a bipolar filter plate, and the maximum inclusion size of the melt after filtration is no greater than 10 μm.

10. The method for preparing an integrated heat-treatment-free aluminum alloy material for vehicles according to claim 6, characterized in that: The die-casting conditions in step (7) include: the melt temperature in the holding furnace is controlled at 650-670°C; the mold temperature controller is set at 210-230°C; the low-speed injection speed of the die-casting machine is 0.08-0.15m / s, and the high-speed injection speed of the die-casting machine is 3.5-4.5m / s; the die-casting pressure is 70-90MPa; and the vacuum degree in the mold cavity is not greater than 7kPa.

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