An aluminum alloy material without homogenization heat treatment and a preparation method and application thereof

Abstract

The application belongs to the field of aluminum alloy materials, and particularly relates to an aluminum alloy material free of homogenization heat treatment and a preparation method and application thereof. The aluminum alloy material free of homogenization heat treatment is composed of the following components in percentage by mass: Si: 0.2-0.6%, Mg: 0.3-0.9%, Cu: 0.1-0.15%, Cr: 0.05-0.1%, Zn: 0.1-0.15%, Mn: 0.1-0.15%, Ti: 0.1-0.15%, Yb: 0.1-0.3%, Zr: 0.05-0.15%, La: 0.1-0.4%, Sm: 0.05-0.35%, Nd: 0-0.2%, Fe: less than or equal to 0.3%, and the balance being Al. Through micro-alloying modification and electromagnetic stirring, the original aluminum alloy performance advantages are retained, the aluminum alloy manufacturing process is shortened, and the manufacturing cost is reduced in the case of being free of homogenization heat treatment.

Description

Technical Field

[0001] This invention belongs to the field of aluminum alloy material technology, specifically relating to an aluminum alloy material that does not require homogenization heat treatment, its preparation method, and its application. Background Technology

[0002] The global energy crisis and environmental problems are becoming increasingly severe, accelerating the application of lightweight technologies. The core of lightweight technology lies in the synergy of material and structural innovation. Aluminum is the most abundant metallic element in the earth's crust (accounting for 8.13 wt%), and its industrial application scale is second only to steel, ranking second in global metal consumption. Aluminum alloys have become the preferred material for lightweight design. This is because they have the following unique properties: (1) They have the characteristics of low density and high specific strength. Their density is only 1 / 3 of that of steel, while their specific strength can reach the level of high-strength steel; (2) They have excellent forming performance and can adapt to complex forming processes such as stamping and casting; (3) They have outstanding recyclability. The energy consumption of recycled aluminum production is only 5% of that of primary aluminum production; (4) They have excellent comprehensive mechanical properties, and their strength, toughness and other indicators can be effectively controlled through alloying.

[0003] The distribution and state of various non-equilibrium phases generated during the casting process of aluminum alloys necessitate a prolonged homogenization treatment of the as-cast aluminum alloy before deformation processing to improve its performance. However, the homogenization heat treatment process not only increases the manufacturing steps and production cycle of aluminum alloy products, but it is also extremely energy-intensive, generally accounting for more than 40% of the total energy consumption of the heat treatment process, thus increasing the overall manufacturing cost for enterprises. Summary of the Invention

[0004] The purpose of this invention is to provide an aluminum alloy material that does not require homogenization heat treatment, its preparation method, and its application, thereby overcoming the shortcomings of the prior art. By using micro-alloying modification and electromagnetic stirring to assist in the preparation of aluminum alloy materials that do not require homogenization heat treatment, the grain structure and non-equilibrium phase distribution of cast aluminum alloys are improved. This allows the aluminum alloy material to retain the original performance advantages of the aluminum alloy without the need for homogenization heat treatment, while also shortening the aluminum alloy manufacturing process and reducing manufacturing costs.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] In a first aspect, the present invention provides an aluminum alloy material that does not require homogenization heat treatment, comprising basic elements and microalloyed rare earth elements, wherein the basic elements are composed of the following by mass percentage: Si: 0.2-0.6%, Mg: 0.3-0.9%, Cu: 0.1-0.15%, Cr: 0.05-0.1%, Zn: 0.1-0.15%, Mn: 0.1-0.15%, Ti: 0.1-0.15%; the microalloyed rare earth elements are composed of the following by mass percentage: Yb: 0.1-0.3%, Zr: 0.05-0.15%, La: 0.1-0.4%, Sm: 0.05-0.35%, Nd: 0-0.2%, impurity Fe≤0.3%, and the balance being Al.

[0007] Specifically, a homogenization-free heat-treated aluminum alloy material comprises basic elements and microalloyed rare earth elements. The basic elements, by mass percentage, are as follows: Si: 0.2%, 0.3%, 0.4%, 0.5%, or 0.6%; Mg: 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, or 0.9%; Cu: 0.1% or 0.15%; Cr: 0.05% or 0.1%; Zn: 0.1% or 0.15%; Mn: 0.1% or 0.15%; Ti: 0.1% or 0.15%. The microalloyed rare earth elements, by mass percentage, are as follows: Yb: 0.1%, 0.2%, or 0.3%; Zr: 0.05%, 0.1%, or 0.15%; La: 0.1%, 0.2%, 0.3%, or 0.4%. %, Sm: 0.05%, 0.1%, 0.2%, 0.3% or 0.35%, Nd: 0%, 0.05%, 0.1% or 0.2%, impurities Fe≤0.3%, balance Al.

[0008] More specifically, a homogenization-free heat-treated aluminum alloy material comprises basic elements and microalloyed rare earth elements. The basic elements, by mass percentage, are as follows: Si: 0.2%, Mg: 0.3%, Cu: 0.1%, Cr: 0.05%, Zn: 0.1%, Mn: 0.1%, Ti: 0.1%. The microalloyed rare earth elements, by mass percentage, are as follows: Yb: 0.1%, Zr: 0.05%, La: 0.1%, Sm: 0.05%, Nd: 0.05%, with the balance being Al.

[0009] Alternatively, the basic elements are composed of the following by mass percentage: Si: 0.6%, Mg: 0.9%, Cu: 0.15%, Cr: 0.1%, Zn: 0.15%, Mn: 0.1%, Ti: 0.1%; the microalloyed rare earth elements are composed of the following by mass percentage: Yb: 0.2%, Zr: 0.15%, La: 0.4%, Sm: 0.1%; the balance is Al.

[0010] Alternatively, the basic elements are composed of the following by mass percentage: Si: 0.3%, Mg: 0.5%, Cu: 0.15%, Cr: 0.05%, Zn: 0.1%, Mn: 0.1%, Ti: 0.1%; the microalloyed rare earth elements are composed of the following by mass percentage: Yb: 0.3%, Zr: 0.1%, La: 0.1%, Sm: 0.35%; Nd: 0.05%; the balance is Al;

[0011] Alternatively, the basic elements are composed of the following by mass percentage: Si: 0.4%, Mg: 0.6%, Cu: 0.1%, Cr: 0.05%, Zn: 0.15%, Mn: 0.1%, Ti: 0.1%; the microalloyed rare earth elements are composed of the following by mass percentage: Yb: 0.2%, Zr: 0.1%, La: 0.2%, Sm: 0.15%; Nd: 0.15%; the balance is Al;

[0012] Alternatively, the basic elements are composed of the following by mass percentage: Si: 0.5%, Mg: 0.8%, Cu: 0.15%, Cr: 0.1%, Zn: 0.15%, Mn: 0.1%, Ti: 0.1%; the microalloyed rare earth elements are composed of the following by mass percentage: Yb: 0.2%, Zr: 0.15%, La: 0.1%, Sm: 0.2%; Nd: 0.2%; the balance is Al.

[0013] Alternatively, the basic elements are composed of the following by mass percentage: Si: 0.5%, Mg: 0.8%, Cu: 0.15%, Cr: 0.1%, Zn: 0.15%, Mn: 0.1%, Ti: 0.1%; the microalloyed rare earth elements are composed of the following by mass percentage: Yb: 0.15%, Zr: 0.15%, La: 0.3%, Sm: 0.1%; Nd: 0.1%; the balance is Al;

[0014] Alternatively, the basic elements are composed of the following by mass percentage: Si: 0.5%, Mg: 0.8%, Cu: 0.15%, Cr: 0.1%, Zn: 0.15%, Mn: 0.1%, Ti: 0.1%; the microalloyed rare earth elements are composed of the following by mass percentage: Yb: 0.2%, Zr: 0.15%, La: 0.1%, Sm: 0.3%; Nd: 0.1%; the balance is Al.

[0015] The present invention, by introducing micro-alloyed rare earth elements into the basic elements, has the following advantages:

[0016] (1) The addition of rare earth microalloying elements Zr and Yb can form an L12 type core-shell structure phase that is coherent with the Al matrix. Since this phase is coherent with Al and has very similar lattice parameters, it can serve as an effective heterogeneous nucleation point during alloy melting and casting, significantly increasing the number of nuclei in the aluminum alloy and refining the grain structure of the Al matrix. In addition, Zr, which has a low diffusion coefficient at high temperatures, is located on the outside of the Al3(Zr,Yb) core-shell structure, making this phase highly resistant to coarsening and exhibiting significant high-temperature stability, which can significantly increase the heat resistance of aluminum alloy materials.

[0017] (2) The introduction of rare earth elements with lower electronegativity, such as La (1.10), Sm (1.17), and Nd (1.14), significantly reduces their electronegativity compared to Al (1.61), making them more chemically reactive. This effectively reduces the surface tension at the solid-liquid interface, decreases the contact angle, and increases wettability. According to the relationship between the critical nucleation work and the contact angle in heterogeneous nucleation processes, the smaller the contact angle, the smaller the critical nucleation work, which greatly increases the nucleation rate and the number of nuclei during alloy solidification. The three rare earth elements and the Al3(Zr,Yb) core-shell structure work synergistically to significantly refine the aluminum matrix grains. The refined grain structure in the aluminum matrix effectively reduces intragranular segregation of elements; the numerous fine grain structures in the aluminum alloy matrix effectively alleviate intragranular segregation, which is equivalent to the effect of reducing intragranular segregation through atomic diffusion during homogenization heat treatment.

[0018] (3) The added rare earth microalloying elements La, Sm, and Nd can also regulate the morphology, size, and quantity of the non-equilibrium second phase in aluminum alloys, thus optimizing the morphology of the second phase. The β-AlFeSi needle-like harmful phase commonly found in 6xxx aluminum alloys is transformed into harmless AlFeLa, AlFeSmSi, and AlFeNdSi phases through modification treatment. La can preferentially segregate at grain boundaries, promoting the breakage and spheroidization of the long needle-like β-AlFeSi phase, thereby reducing its harmfulness. Sm can significantly promote the transformation of the long needle-like β-Fe phase into the Chinese character-shaped α-AlFeSi phase, reducing the average phase size of the Fe-containing phase by more than 50%. Nd can effectively inhibit the segregation of Fe, breaking the continuous network structure of the Fe-containing phase, and further reducing the harmfulness of the Fe-containing phase. Through the combined action of the three rare earth elements La, Sm, and Nd, the morphology of the harmful β-AlFeSi phase is also transformed from long needle-like structures that cut through the aluminum matrix to short rod-like and granular structures. Its effect is equivalent to the spheroidization of needle-like harmful phases during the homogenization heat treatment process through long-term high-temperature heat treatment, thereby reducing their harmfulness.

[0019] In some other embodiments, the total mass percentage of Mg and Si in the base elements is 0.5-1.5%, and the ratio of the mass percentage of Mg to the mass percentage of Si is ≤1.73. The main strengthening mechanism of 6xxx series aluminum alloys is age hardening, and its core strengthening phase is the metastable β phase, with the final stable phase being Mg2Si. Within this range, it is ensured that Mg and Si can completely react to form the Mg2Si compound, which forms the strengthening phase.

[0020] In some other embodiments, the total mass percentage of Zr and Yb in the microalloyed rare earth elements is ≤0.4%, and the total mass percentage of La, Sm, and Nd is ≤0.5%. This range of trace additions can directionally optimize the heat resistance and mechanical properties of 6xxx alloys without compromising processability through a synergistic mechanism of "pinning grain boundaries + purifying the melt + assisting precipitation".

[0021] In some other embodiments, the room temperature tensile strength of the aluminum alloy material without homogenization heat treatment is ≥194 MPa, the room temperature yield strength is ≥167 MPa, and the elongation after fracture is ≥8.2%.

[0022] Secondly, the present invention provides a method for preparing the aluminum alloy material without homogenization heat treatment as described in the first aspect, comprising the following steps:

[0023] The materials are batched according to their elemental composition and then smelted, degassed, slag removed, and refined. During the solidification process of the melt, a low-frequency electromagnetic field is applied for stirring. The melt is then allowed to cool down before casting. Without the need for homogenization treatment, the aluminum alloy material can be directly extruded, solution-treated, and aged for heat treatment to obtain a homogenization-free heat treatment aluminum alloy material.

[0024] By rationally modifying rare earth microalloying, the problem of inclusions like Al2O3, which are unavoidably introduced during casting, cannot be eliminated during homogenization heat treatment. The rare earth elements introduced in this invention typically lose two electrons from their outermost 6s layer and one electron from their penultimate 5d or 4f layer, forming trivalent ions. These ions can react with [H] dissolved in the aluminum melt, effectively reducing hydrogen porosity during casting. Furthermore, these trivalent rare earth ions can also react with Al2O3.

[0025] 2RE (s) + Al2O3(s) = 2Al (l) + RE2O3 (multi-component rare earth aluminum oxide)

[0026] These multi-element composite rare earth oxides have a much higher density than molten aluminum and can be removed by gravity settling, while the original Al2O3 is reduced to elemental aluminum and returned to the molten aluminum. Simultaneously, introducing electromagnetic stirring during alloy casting increases the effective distribution coefficient of alloying elements. The applied electromagnetic field accelerates the cooling rate at the solidification front, causing more Mg and Si atoms to solidify in the Al matrix. This significantly increases the supersaturated solid solubility of the Mg2Si phase in the aluminum matrix, inhibits the precipitation of the Mg2Si phase between grains, and significantly reduces the volume fraction of the Mg2Si phase. The microsegregation of the main alloying elements Mg and Si in the ingot is thus significantly improved.

[0027] In some other embodiments, the melting temperature is 750-850°C; the gas used for degassing is hexachloroethane or argon;

[0028] The refining temperature is 740-750℃.

[0029] In some other embodiments, the magnetic field current intensity of the low-frequency electromagnetic field ranges from 70 to 110 A, and the magnetic field frequency ranges from 10 to 30 Hz. Within this range, strength and toughness can be significantly improved, solute elements such as Mg and Si can be suppressed to accumulate at grain boundaries, resulting in a more uniform composition distribution.

[0030] In some other embodiments, after refining, the mixture is allowed to stand for 15-20 minutes and then cooled to 700-730°C;

[0031] The extrusion temperature is 380-520℃;

[0032] The solution treatment temperature is 500-550℃, and the time is 1.5-2.5 h;

[0033] The aging heat treatment temperature is 150-200℃, and the time is 5-7h.

[0034] When the prepared aluminum alloy material is extruded or forged, no homogenization treatment is required after casting; the cast ingot is directly subjected to hot deformation. The solution-aging treatment process after deformation is similar to that of general aluminum alloys, and no additional processing is required.

[0035] In some other embodiments, the raw materials used are A00 standard aluminum, pure Zn, pure Cu, pure Mg, Al-20%Si, Al-20%Cr, Al-10%Mn, Al-10%Ti, Al-20%Yb, Al-5%Zr, Al-20%La, Al-20%Sm, and Al-20%Nd master alloys, respectively; the purity of A00 standard aluminum, pure Zn, pure Cu, and pure Mg is ≥99.7%.

[0036] Thirdly, the present invention provides the application of the homogenization-free heat-treated aluminum alloy material described in the first aspect in the fields of aerospace, automotive, petroleum equipment and electronics.

[0037] Beneficial effects:

[0038] (1) This invention, by introducing suitable microalloying rare earth elements on the basis of the basic elements, can transform the common AlFeSi needle-like harmful phase in 6xxx aluminum alloys into AlFeLa, AlFeSmSi, and AlFeNdSi. The morphology of the harmful phase is changed from long needle-like structures that cut through the aluminum matrix to short rod-like and granular structures. Its effect is equivalent to the spheroidization of the needle-like harmful phase through prolonged high-temperature heat treatment during homogenization heat treatment, effectively reducing its harmfulness.

[0039] (2) Through the grain refinement effect of rare earth microalloying, the present invention can achieve the same effect as the conventional homogenization treatment of cast aluminum alloy before aluminum alloy deformation processing. It can also make the composition in the aluminum matrix more uniform, effectively increase the supersaturated solid solubility of Mg2Si phase in aluminum matrix, inhibit the precipitation of Mg2Si phase in the intergranular space, and effectively improve the grain structure and non-equilibrium phase distribution of cast aluminum alloy.

[0040] In summary, the rare earth microalloying and electromagnetic stirring-assisted method proposed in this invention can effectively replace the homogenization heat treatment process, shorten the manufacturing process of aluminum alloy products, significantly reduce enterprise production costs, and enhance the competitiveness of enterprise aluminum alloy products. Detailed Implementation

[0041] Those skilled in the art will understand that the following embodiments are for illustrative purposes only and should not be construed as limiting the scope of the invention. Specific conditions not specified in the embodiments are performed under conventional conditions or conditions recommended by the manufacturer. Components whose manufacturers are not specified are all commercially available conventional products.

[0042] This invention addresses the existing aluminum alloy casting process, which often improves the performance of aluminum alloys by homogenizing heat treatment to improve the distribution and state of various non-equilibrium phases. The mechanism of homogenization heat treatment is as follows: (1) Through long-term high-temperature heat treatment, atomic diffusion is achieved, reducing the compositional segregation within the grains and making the composition within the grains more uniform. Aluminum alloys with fine grains have a greater number of grains, and the compositional distribution is significantly more uniform compared to large grains. (2) The amount of Mg2Si non-equilibrium eutectic phase between grains is reduced, allowing the Mg2Si phase to redissolve in the aluminum matrix and increasing the supersaturated solid solubility of the Mg2Si phase. (3) The morphology of the AlFeSi needle-like harmful phase is controlled, reducing its cutting effect on the aluminum matrix.

[0043] However, the homogenization heat treatment process not only increases the manufacturing steps and production cycle of aluminum alloy products, but it is also extremely energy-intensive, significantly increasing the overall manufacturing costs for enterprises. Furthermore, the homogenization heat treatment process has a drawback: it cannot eliminate inclusions such as Al2O3 that are inevitably introduced during the casting process. Therefore, developing a process that retains the original performance advantages of aluminum alloys while shortening the manufacturing steps and reducing manufacturing costs has become an urgent technical problem to be solved.

[0044] The solution of this application is described below with reference to specific embodiments and comparative examples:

[0045] I. Material Preparation

[0046] Example 1

[0047] This embodiment provides an aluminum alloy material that does not require homogenization heat treatment, comprising basic elements and microalloyed rare earth elements. The basic elements are composed of the following by mass percentage: Si: 0.2%, Mg: 0.3%, Cu: 0.1%, Cr: 0.05%, Zn: 0.1%, Mn: 0.1%, Ti: 0.1%; the microalloyed rare earth elements are composed of the following by mass percentage: Yb: 0.1%, Zr: 0.05%, La: 0.1%, Sm: 0.05%, Nd: 0.05%; the balance is Al.

[0048] The above-mentioned method for preparing aluminum alloy materials that do not require homogenization heat treatment includes the following steps:

[0049] (1) Weigh out A00 standard aluminum, pure Zn, pure Cu, pure Mg, Al-20%Si, Al-20%Cr, Al-10%Mn, Al-10%Ti, Al-20%Yb, Al-5%Zr, Al-20%La, Al-20%Sm, and Al-20%Nd master alloys and add them to the aluminum alloy melting furnace.

[0050] (2) The aluminum alloy was melted at 760°C, and hexachloroethane was pressed into the bell jar to degas it. Then, the slag was removed and refined at 740°C. The aluminum alloy was stirred in a low-frequency electromagnetic field with a current intensity of 70A and an electromagnetic frequency of 10Hz. After that, the aluminum alloy was allowed to stand and cool down to 700°C before casting to obtain the aluminum alloy material.

[0051] (3) The aluminum alloy material does not require homogenization treatment. It is directly extruded at 480℃. After extrusion, it is solution-treated at 550℃ for 2 hours and then rapidly quenched. Finally, it is aged at 180℃ for 6 hours.

[0052] Example 2

[0053] This embodiment provides an aluminum alloy material that does not require homogenization heat treatment, comprising basic elements and microalloyed rare earth elements. The basic elements are composed of the following by mass percentage: Si: 0.6%, Mg: 0.9%, Cu: 0.15%, Cr: 0.1%, Zn: 0.15%, Mn: 0.1%, Ti: 0.1%; the microalloyed rare earth elements are composed of the following by mass percentage: Yb: 0.2%, Zr: 0.15%, La: 0.4%, Sm: 0.1%; the balance is Al.

[0054] The above-mentioned method for preparing aluminum alloy materials that do not require homogenization heat treatment includes the following steps:

[0055] (1) Weigh out A00 standard aluminum, pure Zn, pure Cu, pure Mg and Al-20%Si, Al-20%Cr, Al-10%Mn, Al-10%Ti, Al-20%Yb, Al-5%Zr, Al-20%La and Al-20%Sm master alloys according to the mass ratio;

[0056] (2) The raw materials are smelted at 760°C to form aluminum alloy, then hexachloroethane is pressed into the bell jar to degas the material, and then the slag is removed and refined at 740°C. The material is then subjected to low-frequency electromagnetic field stirring treatment with a current intensity of 80A and an electromagnetic frequency of 15Hz. After that, the material is allowed to stand and cool down to 700°C before casting.

[0057] (3) The aluminum alloy material does not require homogenization treatment. It is directly extruded at 500℃. After extrusion, it is solution-treated at 550℃ for 2 hours and then rapidly quenched. Finally, it is aged at 180℃ for 6 hours.

[0058] Example 3

[0059] This embodiment provides an aluminum alloy material that does not require homogenization heat treatment, comprising basic elements and microalloyed rare earth elements. The basic elements are composed of the following by mass percentage: Si: 0.3%, Mg: 0.5%, Cu: 0.15%, Cr: 0.05%, Zn: 0.1%, Mn: 0.1%, Ti: 0.1%. The microalloyed rare earth elements are composed of the following by mass percentage: Yb: 0.3%, Zr: 0.1%, La: 0.1%, Sm: 0.35%, Nd: 0.05%, with the balance being Al.

[0060] The above-mentioned method for preparing aluminum alloy materials that do not require homogenization heat treatment includes the following steps:

[0061] (1) Weigh out A00 standard aluminum, pure Zn, pure Cu, pure Mg and Al-20%Si, Al-20%Cr, Al-10%Mn, Al-10%Ti, Al-20%Yb, Al-5%Zr, Al-20%La, Al-20%Sm, and Al-20%Nd master alloys according to the mass ratio;

[0062] (2) The raw materials are smelted at 760°C to form aluminum alloy, then hexachloroethane is pressed into the bell jar to degas the material, and then the slag is removed and refined at 740°C. The material is then subjected to low-frequency electromagnetic field stirring treatment with a current intensity of 90A and an electromagnetic frequency of 20Hz. After that, the material is allowed to stand and cool down to 700°C before casting.

[0063] (3) The aluminum alloy material does not require homogenization treatment. It is directly extruded at 500℃. After extrusion, it is solution-treated at 550℃ for 2 hours and then rapidly quenched. Finally, it is aged at 180℃ for 6 hours.

[0064] Example 4

[0065] This embodiment provides an aluminum alloy material that does not require homogenization heat treatment, comprising basic elements and microalloyed rare earth elements. The basic elements are composed of the following by mass percentage: Si: 0.4%, Mg: 0.6%, Cu: 0.1%, Cr: 0.05%, Zn: 0.15%, Mn: 0.1%, Ti: 0.1%. The microalloyed rare earth elements are composed of the following by mass percentage: Yb: 0.2%, Zr: 0.1%, La: 0.2%, Sm: 0.15%, Nd: 0.15%, with the balance being Al.

[0066] The above-mentioned method for preparing aluminum alloy materials that do not require homogenization heat treatment includes the following steps:

[0067] (1) Weigh out A00 standard aluminum, pure Zn, pure Cu, pure Mg and Al-20%Si, Al-20%Cr, Al-10%Mn, Al-10%Ti, Al-20%Yb, Al-5%Zr, Al-20%La, Al-20%Sm, and Al-20%Nd master alloys according to the mass ratio;

[0068] (2) The raw materials are smelted at 760°C to form aluminum alloy, and then argon gas is introduced into the melt to degas it. Then, the slag is removed and refined at 740°C. The mixture is then subjected to low-frequency electromagnetic field stirring treatment with a current intensity of 100A and an electromagnetic frequency of 25Hz. After that, it is allowed to stand and cool down to 700°C before casting.

[0069] (3) The aluminum alloy material does not require homogenization treatment. It is directly extruded at 500℃. After extrusion, it is solution-treated at 550℃ for 2 hours and then rapidly quenched. Finally, it is aged at 180℃ for 6 hours.

[0070] Example 5

[0071] This embodiment provides an aluminum alloy material that does not require homogenization heat treatment, comprising basic elements and microalloyed rare earth elements. The basic elements are composed of the following by mass percentage: Si: 0.5%, Mg: 0.8%, Cu: 0.15%, Cr: 0.1%, Zn: 0.15%, Mn: 0.1%, Ti: 0.1%. The microalloyed rare earth elements are composed of the following by mass percentage: Yb: 0.2%, Zr: 0.15%, La: 0.1%, Sm: 0.2%, Nd: 0.2%, with the balance being Al.

[0072] The above-mentioned method for preparing aluminum alloy materials that do not require homogenization heat treatment includes the following steps:

[0073] (1) Weigh out A00 standard aluminum, pure Zn, pure Cu, pure Mg and Al-20%Si, Al-20%Cr, Al-10%Mn, Al-10%Ti, Al-20%Yb, Al-5%Zr, Al-20%La, Al-20%Sm, and Al-20%Nd master alloys according to the mass ratio;

[0074] (2) The raw materials are smelted at 760°C to form aluminum alloy, and then argon gas is introduced into the melt to degas it. Then, the slag is removed and refined at 740°C. The low-frequency electromagnetic field is stirred, with a current intensity of 110A and an electromagnetic frequency of 30Hz. After that, the temperature is allowed to drop to 700°C before casting.

[0075] (3) The aluminum alloy material does not require homogenization treatment. It is directly extruded at 500℃. After extrusion, it is solution-treated at 550℃ for 2 hours and then rapidly quenched. Finally, it is aged at 180℃ for 6 hours.

[0076] Example 6

[0077] This embodiment provides an aluminum alloy material that does not require homogenization heat treatment, comprising basic elements and microalloyed rare earth elements. The basic elements are composed of the following by mass percentage: Si: 0.5%, Mg: 0.8%, Cu: 0.15%, Cr: 0.1%, Zn: 0.15%, Mn: 0.1%, Ti: 0.1%. The microalloyed rare earth elements are composed of the following by mass percentage: Yb: 0.15%, Zr: 0.15%, La: 0.3%, Sm: 0.1%, Nd: 0.1%, with the balance being Al.

[0078] The above-mentioned method for preparing aluminum alloy materials that do not require homogenization heat treatment includes the following steps:

[0079] (1) Weigh out A00 standard aluminum, pure Zn, pure Cu, pure Mg and Al-20%Si, Al-20%Cr, Al-10%Mn, Al-10%Ti, Al-20%Yb, Al-5%Zr, Al-20%La, Al-20%Sm, and Al-20%Nd master alloys according to the mass ratio;

[0080] (2) The raw materials are smelted at 760°C to form aluminum alloy, and then argon gas is introduced into the melt to degas it. Then, the slag is removed and refined at 740°C. The low-frequency electromagnetic field is stirred, with a current intensity of 100A and an electromagnetic frequency of 15Hz. After that, the temperature is allowed to drop to 700°C before casting.

[0081] (3) The aluminum alloy material does not require homogenization treatment. It is directly extruded at 500℃. After extrusion, it is solution-treated at 550℃ for 2 hours and then rapidly quenched. Finally, it is aged at 180℃ for 6 hours.

[0082] Example 7

[0083] This embodiment provides an aluminum alloy material that does not require homogenization heat treatment, comprising basic elements and microalloyed rare earth elements. The basic elements are composed of the following by mass percentage: Si: 0.5%, Mg: 0.8%, Cu: 0.15%, Cr: 0.1%, Zn: 0.15%, Mn: 0.1%, Ti: 0.1%. The microalloyed rare earth elements are composed of the following by mass percentage: Yb: 0.2%, Zr: 0.15%, La: 0.1%, Sm: 0.3%, Nd: 0.1%, with the balance being Al.

[0084] The above-mentioned method for preparing aluminum alloy materials that do not require homogenization heat treatment includes the following steps:

[0085] (1) Weigh out A00 standard aluminum, pure Zn, pure Cu, pure Mg and Al-20%Si, Al-20%Cr, Al-10%Mn, Al-10%Ti, Al-20%Yb, Al-5%Zr, Al-20%La, Al-20%Sm, and Al-20%Nd master alloys according to the mass ratio;

[0086] (2) The raw materials are smelted at 760°C to form aluminum alloy, and then argon gas is introduced into the melt to degas it. Then, the slag is removed and refined at 740°C. The low-frequency electromagnetic field is stirred, with a current intensity of 105A and an electromagnetic frequency of 25Hz. After that, the temperature is allowed to drop to 700°C before casting.

[0087] (3) The aluminum alloy material does not require homogenization treatment. It is directly extruded at 500℃. After extrusion, it is solution-treated at 550℃ for 2 hours and then rapidly quenched. Finally, it is aged at 180℃ for 6 hours.

[0088] Comparative Example 1

[0089] Unlike Example 2, the aluminum alloy material contains only basic elements, and its composition by mass percentage is as follows: Si: 0.6%, Mg: 0.9%, Cu: 0.15%, Cr: 0.1%, Zn: 0.15%, Mn: 0.1%, Ti: 0.1%; the balance is Al.

[0090] The preparation method is the same as in Example 2.

[0091] Comparative Example 2

[0092] Unlike Example 2, the aluminum alloy material includes basic elements and microalloyed rare earth elements. The basic elements are composed of the following by mass percentage: Si: 0.6%, Mg: 0.9%, Cu: 0.15%, Cr: 0.1%, Zn: 0.15%, Mn: 0.1%, Ti: 0.1%; the microalloyed rare earth elements are composed of the following by mass percentage: Yb: 0.2%, Zr: 0.15%; the balance is Al.

[0093] The preparation method is the same as in Example 2.

[0094] Comparative Example 3

[0095] Unlike Example 2, the aluminum alloy material includes basic elements and microalloyed rare earth elements. The basic elements are composed of the following by mass percentage: Si: 0.6%, Mg: 0.9%, Cu: 0.15%, Cr: 0.1%, Zn: 0.15%, Mn: 0.1%, Ti: 0.1%; the microalloyed rare earth elements are composed of the following by mass percentage: La: 0.4%, Sm: 0.1%; the balance is Al.

[0096] The preparation method is the same as in Example 2.

[0097] Comparative Example 4

[0098] Unlike Example 2, the preparation method does not involve low-frequency electromagnetic field stirring, but the other preparation steps are the same as in Example 2.

[0099] II. Performance Testing

[0100] The mechanical properties of the embodiments and comparative examples are shown in Table 1 below. The tensile properties, yield strength and elongation after fracture were tested according to GB / T228.1-2010 standard.

[0101] Table 1. Mechanical property test results

[0102]

[0103] As shown in Table 1, in Example 1, due to the low content of the main alloying elements Si and Mg in the prepared aluminum alloy material, the amount of the final generated age-hardening phase Mg2Si was relatively small, resulting in lower tensile properties and a tensile strength of 194 MPa compared to other examples. In Example 2, the aluminum alloy material had the highest addition of the main alloying elements Si and Mg, resulting in the largest number of generated Mg2Si age-hardening phases, thus exhibiting the highest mechanical properties and a tensile strength of 257 MPa. In Examples 3-7, the tensile properties varied between the two examples depending on the amount of Si and Mg added.

[0104] Comparative Example 1 shows that the aluminum alloy material contains only basic elements and no microalloyed rare earth elements are added, resulting in significantly poor mechanical properties. This demonstrates that the added microalloyed rare earth elements can significantly refine the alloy structure, improve the morphology of precipitated phases, reduce casting defects, and enhance the mechanical properties of the alloy, with remarkable effects.

[0105] In Comparative Example 2, the aluminum alloy material only added microalloying rare earth elements Yb and Zr, without adding La, Sm, and Nd. This resulted in the presence of long needle-like AlFeSi harmful phases in the alloy, which easily caused stress concentration, disrupted the alloy's microstructure, and reduced the alloy's mechanical properties.

[0106] In Comparative Example 3, only La and Sm, rare earth elements in microalloying, were added to the aluminum alloy material, while Yb, Zr, and Nd were not added. This resulted in a relatively coarse grain structure and uneven distribution of alloying elements, which had a significant impact on the subsequent extrusion performance and aging treatment, and resulted in lower mechanical properties.

[0107] In the preparation method of Comparative Example 4, low-frequency electromagnetic field stirring was not performed, which resulted in a smaller cooling rate at the solidification front of the alloy, a decrease in the supersaturated solid solubility of the Mg2Si phase in the aluminum matrix, an increase in the amount of Mg2Si phase precipitates in the intergranular space, an increase in the degree of alloy element segregation, and ultimately a decrease in the mechanical properties of the alloy.

[0108] Based on the above analysis, it can be seen that the present invention adds effective rare earth microalloying elements and performs low-frequency electromagnetic stirring during the preparation of aluminum alloy materials. Therefore, although no homogenization heat treatment is performed before hot extrusion, the final aluminum alloy material still exhibits excellent mechanical properties. Moreover, due to the synergistic optimization effect of the added rare earth elements, the mechanical properties are significantly improved compared with aluminum alloy materials with similar compositions currently available.

[0109] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing aluminum alloy materials without homogenization heat treatment, characterized in that, It includes basic elements and microalloyed rare earth elements. The basic elements are composed of the following by mass percentage: Si: 0.2-0.6%, Mg: 0.3-0.9%, Cu: 0.1-0.15%, Cr: 0.05-0.1%, Zn: 0.1-0.15%, Mn: 0.1-0.15%, Ti: 0.1-0.15%. The microalloyed rare earth elements are composed of the following by mass percentage: Yb: 0.1-0.3%, Zr: 0.05-0.15%, La: 0.1-0.4%, Sm: 0.05-0.35%, Nd: 0-0.2%, impurity Fe≤0.3%, balance Al. The preparation method of the aluminum alloy material that does not require homogenization heat treatment includes the following steps: The materials are batched according to their elemental composition and then smelted, degassed, slag removed, and refined. A low-frequency electromagnetic field is applied during the solidification of the melt for stirring. The melt is allowed to stand and cool down before casting. No homogenization treatment is required. Extrusion, solution treatment, and aging heat treatment are then performed to obtain aluminum alloy materials that do not require homogenization heat treatment. The magnetic field current intensity of the low-frequency electromagnetic field ranges from 70 to 110 A, and the magnetic field frequency ranges from 10 to 30 Hz. The extrusion temperature is 380-520℃; The solution treatment temperature is 500-550℃, and the time is 1.5-2.5 h; The aging heat treatment is performed at a temperature of 150-200℃ for 5-7 hours.

2. The method for preparing aluminum alloy materials without homogenization heat treatment according to claim 1, characterized in that, Among the basic elements, the total mass percentage of Mg and Si is 0.5-1.5%, and the ratio of the mass percentage of Mg to the mass percentage of Si is ≤1.

73.

3. The method for preparing aluminum alloy materials without homogenization heat treatment according to claim 1, characterized in that, In the microalloyed rare earth elements, the total mass percentage of Zr and Yb is ≤0.4%, and the total mass percentage of La, Sm and Nd is ≤0.5%.

4. The method for preparing aluminum alloy materials without homogenization heat treatment according to claim 1, characterized in that, The room temperature tensile strength of the aluminum alloy material that does not require homogenization heat treatment is ≥194 MPa, the room temperature yield strength is ≥167 MPa, and the elongation after fracture is ≥8.2%.

5. The method for preparing aluminum alloy materials without homogenization heat treatment according to claim 1, characterized in that, The melting temperature is 750-850℃; the degassing reagent used is hexachloroethane or inert gas argon. The refining temperature is 740-750℃.

6. The method for preparing aluminum alloy materials without homogenization heat treatment according to claim 1, characterized in that, After refining, the mixture is allowed to stand for 15-20 minutes and then cooled to 700-730℃.

7. The method for preparing aluminum alloy materials without homogenization heat treatment according to claim 1, characterized in that, The raw materials used are A00 standard aluminum, pure Zn, pure Cu, pure Mg, Al-20%Si, Al-20%Cr, Al-10%Mn, Al-10%Ti, Al-20%Yb, Al-5%Zr, Al-20%La, Al-20%Sm, and Al-20%Nd master alloys; the purity of A00 standard aluminum, pure Zn, pure Cu, and pure Mg is ≥99.7%.

8. The application of a homogenization-free heat-treated aluminum alloy material obtained by the preparation method according to any one of claims 1-7 in the fields of aerospace, automotive, petroleum equipment and electronics.

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