Al-cu high-strength aluminum alloy, preparation method and application thereof

Abstract

The application belongs to the technical field of aluminum alloy, and relates to an Al-Cu high-strength aluminum alloy and a preparation method and application thereof. The Al-Cu high-strength aluminum alloy comprises the following components in mass fraction: Cu 2.9-7.1%, Mn 0.15-1.0%, Ti 0.1-0.35%, Cr 0.05-0.2%, Mo 0.05-0.25%, Zr 0.05-0.2%, Sb 0-0.3%, In 0-0.3%, Sn 0-0.0.15%, Bi 0-0.3%, Ge 0-0.3%, wherein, 0.05%<=Sb+In+Sn<=0.3% or 0.05%<=Bi+Ge<=0.3%. The cold slope casting technology is adopted, and high-temperature solid solution treatment is not needed, and only low-temperature aging treatment is needed. The aluminum alloy has the advantages of short preparation process, fine grains, high strength and the like, and is applied to important fields such as aerospace, automobile electronics and the like.

Description

Technical Field

[0001] This invention belongs to the field of aluminum alloy technology, specifically relating to an Al-Cu high-strength aluminum alloy, its preparation method, and its application. Background Technology

[0002] Lightweighting technology, as a key approach to addressing the energy crisis and environmental pollution, has shown enormous potential in high-end equipment manufacturing sectors such as automobiles and aerospace. Studies show that for every 1 kg reduction in a vehicle's weight, fuel economy can improve by approximately 0.011 km / L, and emissions of gases such as CO2 and nitrogen oxides can be effectively reduced. In the aerospace field, the fuel efficiency gains from weight reduction are even more significant, reaching hundreds of times that of the automotive industry.

[0003] Al-Cu cast aluminum alloys are ideal materials for lightweight structural components due to their excellent high-temperature performance and room-temperature strength. Through the precipitation of stable strengthening phases during heat treatment, these alloys can maintain high mechanical properties at 200–300℃, while also possessing good adaptability to machining and welding processes. They are widely used in aero-engine components, military equipment, and key structures in high-performance automobiles.

[0004] However, the high strength of Al-Cu alloys heavily relies on the "solution treatment + aging (T6) heat treatment" process. While solution treatment can increase the solubility of alloying elements in the aluminum matrix, its high-temperature process not only prolongs the production cycle and increases energy consumption and cost, but also easily induces grain coarsening, weakens grain boundary strengthening, and thus impairs the overall material properties. Therefore, how to achieve high strength in Al-Cu alloys without T6 heat treatment has become a critical technical bottleneck that urgently needs to be overcome in the field of lightweight materials. Summary of the Invention

[0005] The purpose of this invention is to provide an Al-Cu high-strength aluminum alloy, its preparation method, and its applications, thereby overcoming the shortcomings of existing technologies. The Al-Cu high-strength cast aluminum alloy material used has an ultrafine grain structure and high supersaturation. The castings do not require subsequent solution treatment; high mechanical properties can be obtained directly after aging treatment. Simultaneously, it effectively shortens the aluminum alloy material manufacturing process and reduces enterprise manufacturing costs.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows: In a first aspect, the present invention provides an Al-Cu high-strength aluminum alloy comprising the following basic alloying elements by mass fraction: Cu: 2.9~7.1%, Mn: 0.15~1.0%, Ti: 0.1~0.35%, Cr: 0.05~0.2%, Mo: 0.05~0.25%, Zr: 0.05~0.2%; It also includes microalloying auxiliary elements with the following mass fractions: at least one of Sb: 0 - 0.3%, In: 0 - 0.3%, Sn: 0 - 0.15%, Bi: 0 - 0.3%, Ge: 0 - 0.3%; the balance is Al.

[0007] In the high-strength Al-Cu series aluminum alloy material of the present invention, the added Ti and Zr elements can preferentially generate Al3Ti and Al3Zr particles before the Al matrix solidifies, causing heterogeneous nucleation of the Al melt and also having the effect of refining the grains. Due to the harmful element Fe, in addition to generating long needle-shaped harmful phases in the Al-Cu alloy, it also reacts with the main alloying element Cu to form Al7Cu2Fe, thereby reducing the solubility of Cu in the Al matrix and affecting the final age hardening effect.

[0008] In the Al-Cu alloy, Mn, Cr, and Mo elements are added. The Mn and Cr elements can react with the Fe element to transform the β-Fe needle-shaped phase into Al 15 (Fe,Cr)3Si2 Chinese character shape; the Mo element can transform the flaky Fe-containing phase into a dense star-shaped phase. Through the synergistic modification of the three elements Mn, Cr, and Mo, the morphology of the Fe-containing phase is jointly optimized and improved, avoiding the generation of Fe-containing harmful phases, and reducing the harm of Fe to the Cu element, effectively improving the mechanical properties of the alloy.

[0009] In some other embodiments, among the microalloying auxiliary elements, 0.05% ≤ Sb + In + Sn ≤ 0.3% or 0.05% ≤ Bi + Ge ≤ 0.3%.

[0010] In some other embodiments, the impurity content control is as follows: Fe ≤ 0.15%, Si ≤ 0.05%, Mg ≤ 0.05%, and the total amount of other impurities ≤ 0.3%.

[0011] In the second aspect, the present invention provides a preparation method for the Al-Cu series high-strength aluminum alloy described in the first aspect. The alloy raw materials after batching are melted, a refining agent is added for slag removal and refining, and after standing, it is cast onto a steep slope mold to obtain an alloy casting; the alloy casting is subjected to age treatment in sequence to obtain the product.

[0012] In some other embodiments, the melting temperature is 700 - 800 °C; the refining agent is one of C2Cl6 or Ar; the refining temperature is 740 - 750 °C.

[0013] In some other embodiments, the standing time is 10 - 30 min; the casting temperature is 690 - 710 °C.

[0014] In some other embodiments, the steep-slope mold has an inclination angle of 60-70°, which provides an ideal gravity-driven flow for the alloy melt. After being poured in, the melt can spread rapidly and evenly along the inclined surface of the mold, effectively reducing turbulence, splashing, and gas entrapment that are common in traditional flat mold casting. This significantly reduces the risk of defects such as porosity and cold shuts when forming thin-layer cast plates.

[0015] A cooling medium is introduced into the steep-slope mold; the thickness of the alloy casting is ≤10 mm. Specifically, the cooling medium is cooling water; before casting, the circulating cooling water in the steep-slope mold is turned on to quickly remove heat and establish a high-intensity transient heat trap; during the casting process, a constant flow rate is maintained so that the melt is evenly spread into a thin slab with a thickness of ≤10 mm under the combined action of gravity and shear, thereby maximizing the cooling rate and obtaining a rapid solidification structure across the entire cross section.

[0016] The cold-slope casting technique not only forms an ultrafine-grained structure within the alloy but also significantly increases the solid solubility of the main alloying element Cu in the Al matrix, greatly eliminating the intergranular Al-Cu eutectic phase. Therefore, it is possible to prepare Al-Cu aluminum alloys with high Cu content, forming a high-Cu supersaturated solid solution without worrying about excessive Al-Cu eutectic phase that is difficult to eliminate and impairs alloy properties. Consequently, subsequent aging treatment can generate a greater number of Al2Cu nano-aging strengthening phases in the Al matrix, significantly improving the alloy's mechanical properties.

[0017] The rapid cooling process of cold-slope casting technology can also suppress the precipitation of Sb, In, Sn, or Bi, Ge microalloying elements, helping them to exist in a solid solution state in the aluminum matrix and increasing the solid solubility of these microalloying elements in the Al matrix. These elements preferentially nucleate before Al2Cu nucleation, providing nucleation sites for Al2Cu, and also migrate to the Al-Cu interface, significantly reducing the Al2Cu phase interface energy and decreasing the resistance to Al2Cu phase formation. This allows the Al2Cu phase to precipitate uniformly and dispersedly in the Al matrix. Therefore, these microalloying elements have a significant auxiliary effect on the aging precipitation of Al2Cu nanophase, greatly improving the mechanical properties of the alloy.

[0018] In some other embodiments, the aging treatment is carried out at a temperature of 150-200 °C for 5-10 h.

[0019] After casting, the traditional high-temperature solution treatment is abandoned, and the castings are directly subjected to low-temperature aging treatment at 150~200℃. In terms of energy efficiency and economy, by avoiding the high-temperature treatment process, energy consumption is reduced by more than 60%, the processing time is significantly shortened, and production costs and carbon emissions are significantly reduced, which is in line with the concept of green manufacturing. It effectively avoids the risk of casting deformation, warping and cracking caused by high thermal stress, and ensures dimensional accuracy and yield. The aging treatment, through precise control of precipitated phases, enables the castings to obtain strength, hardness and wear resistance comparable to complex solution + aging processes, which is especially suitable for materials such as aluminum-silicon casting alloys. The simplified process shortens the production cycle and improves equipment utilization and capacity.

[0020] In some other embodiments, the purity of the alloy raw material is >99%.

[0021] Thirdly, the present invention provides the application of the Al-Cu high-strength aluminum alloy described in the first aspect in the fields of aerospace, automotive, biomedical, petroleum equipment and electronics.

[0022] The beneficial effects of this invention are: (1) In the alloy of the present invention, the addition of Ti and Zr elements generates Al3Ti and Al3Zr heterogeneous nucleation sites, which further refines the as-cast grains; with the help of the composite addition of Mn, Cr and Mo, the harmful needle-like or plate-like Fe-containing phases are transformed into Chinese character-shaped or star-shaped stable phases, effectively eliminating the negative impact of Fe elements on the solid solubility of Cu and improving the strength and toughness of the alloy. Microalloying elements such as Sb, In and Sn dissolve in the matrix during rapid solidification, providing non-uniform nucleation sites for the Al2Cu phase during the aging stage and reducing its formation energy, promoting the uniform dispersion precipitation of nano-strengthening phases, and significantly enhancing the aging strengthening effect.

[0023] (2) This invention utilizes cold crucible casting to achieve ultra-rapid cooling of the melt, forming a uniform ultrafine grain structure in the as-cast microstructure and enhancing the fine grain strengthening effect; at the same time, it significantly increases the solid solubility of elements such as Cu in the Al matrix, inhibits the formation of intergranular Al-Cu eutectic phase, and lays the microstructure foundation for the precipitation of high-density, dispersed nano-Al2Cu strengthening phase during the subsequent aging process. Microalloying elements such as Sb, In, and Sn dissolve in the matrix during rapid solidification, providing non-uniform nucleation sites for the Al2Cu phase during the aging stage and reducing its formation energy, promoting the uniform and dispersed precipitation of nano-strengthening phase, and significantly enhancing the aging strengthening effect.

[0024] (3) The present invention eliminates the high-temperature solution treatment process required for traditional Al-Cu alloys, and only low-temperature aging is required to achieve high performance. This avoids the risk of grain coarsening, and significantly reduces energy consumption, equipment investment and production cycle, thereby enhancing the product's market competitiveness. Detailed Implementation

[0025] 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.

[0026] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0027] Example 1 An Al-Cu high-strength aluminum alloy material, whose basic elements, by mass percentage, consist of the following components: Cu: 2.9%, Mn: 0.3%, Ti: 0.1%, Cr: 0.05%, Mo: 0.05%, Zr: 0.05%; the added microalloying elements, by mass percentage, consist of the following components: Sb: 0.05%; the balance is Al.

[0028] The preparation method of Al-Cu high-strength aluminum alloy materials is as follows: 1) Weigh out A00 standard aluminum, pure Sb, and Al-30%Cu, Al-5%Mn, Al-2%Ti, Al-20%Cr, Al-20%Mo, and Al-5%Zr master alloys according to the mass ratio.

[0029] 2) The raw materials are smelted into aluminum alloy at 760 ℃, then hexachloroethane is pressed into the bell jar to degas the material, and then the slag is removed and refined at 740 ℃. After refining, the material is allowed to stand for 30 min, and then the temperature is lowered to 700 ℃ for casting.

[0030] 3) Before casting, turn on the cooling water in the cold slope casting mold. During casting, the pouring speed should be uniform so that the alloy melt is evenly spread on the cold slope plane (the cold slope copper mold is at a 60° angle to the plane). After the alloy solidifies, immediately water cool it.

[0031] 4) This aluminum alloy material does not require further solution treatment; it can be directly subjected to aging heat treatment at 180 ℃ for 6 h.

[0032] Example 2 An Al-Cu high-strength aluminum alloy material, whose basic elements are composed of the following components by mass percentage: Cu: 3.3%, Mn: 0.3%, Ti: 0.15%, Cr: 0.05%, Mo: 0.05%, Zr: 0.05%; the added microalloying elements are composed of the following components by mass percentage: In: 0.05%; the balance is Al.

[0033] The preparation method of Al-Cu high-strength aluminum alloy materials is as follows: 1) Weigh out A00 standard aluminum, pure In, and Al-30%Cu, Al-5%Mn, Al-2%Ti, Al-20%Cr, Al-20%Mo, and Al-5%Zr master alloys according to the mass ratio.

[0034] 2) The raw materials are smelted into aluminum alloy at 760 ℃, then hexachloroethane is pressed into the bell jar to degas the material, and then the slag is removed and refined at 740 ℃. After refining, the material is allowed to stand for 30 min, and then the temperature is lowered to 700 ℃ for casting.

[0035] 3) Before casting, turn on the cooling water in the cold slope casting mold. During casting, the pouring speed should be uniform so that the alloy melt is evenly spread on the cold slope plane (the cold slope copper mold is at a 60° angle to the plane). After the alloy solidifies, immediately water cool it.

[0036] 4) This aluminum alloy material does not require further solution treatment; it can be directly subjected to aging heat treatment at 180 ℃ for 6 h.

[0037] Example 3 An Al-Cu high-strength aluminum alloy material, whose basic elements are composed of the following components by mass percentage: Cu: 3.5%, Mn: 0.15%, Ti: 0.15%, Cr: 0.1%, Mo: 0.1%, Zr: 0.05%; the added microalloying elements are composed of the following components by mass percentage: Bi: 0.05%; the balance is Al.

[0038] The preparation method of Al-Cu high-strength aluminum alloy materials is as follows: 1) Weigh out A00 standard aluminum, pure Bi, and master alloys of Al-30%Cu, Al-5%Mn, Al-2%Ti, Al-20%Cr, Al-20%Mo, and Al-5%Zr according to the mass ratio.

[0039] 2) The raw materials are smelted into aluminum alloy at 760 ℃, then hexachloroethane is pressed into the bell jar to degas the material, and then the slag is removed and refined at 740 ℃. After refining, the material is allowed to stand for 30 min, and then the temperature is lowered to 700 ℃ for casting.

[0040] 3) Before casting, turn on the cooling water in the cold slope casting mold. During casting, the pouring speed should be uniform so that the alloy melt is evenly spread on the cold slope plane (the cold slope copper mold is at a 70° angle to the plane). After the alloy solidifies, immediately water cool it.

[0041] 4) This aluminum alloy material does not require further solution treatment; it can be directly subjected to aging heat treatment at 180 ℃ for 6 h.

[0042] Example 4 An Al-Cu high-strength aluminum alloy material, whose basic elements are composed of the following components by mass percentage: Cu: 3.8%, Mn: 0.15%, Ti: 0.15%, Cr: 0.1%, Mo: 0.1%, Zr: 0.05%; the added microalloying elements are composed of the following components by mass percentage: Ge: 0.05%; the balance is Al.

[0043] The preparation method of Al-Cu high-strength aluminum alloy materials is as follows: 1) Weigh out A00 standard aluminum, pure Ge, and master alloys of Al-30%Cu, Al-5%Mn, Al-2%Ti, Al-20%Cr, Al-20%Mo, and Al-5%Zr according to the mass ratio.

[0044] 2) The raw materials are smelted into aluminum alloy at 760 ℃, then degassed with hexachloroethane using a bell jar, and then smelted at 740 ℃. ℃ After slag removal and refining, the mixture is allowed to stand for 30 minutes, then cooled to 700 ℃ before casting.

[0045] 3) Before casting, turn on the cooling water in the cold slope casting mold. During casting, the pouring speed should be uniform so that the alloy melt is evenly spread on the cold slope plane (the cold slope copper mold is at a 60° angle to the plane). After the alloy solidifies, immediately water cool it.

[0046] 4) This aluminum alloy material does not require further solution treatment; it can be directly subjected to aging heat treatment at 180 ℃ for 6 h.

[0047] Example 5 An Al-Cu high-strength aluminum alloy material, whose basic elements, by mass percentage, consist of the following components: Cu: 4.2%, Mn: 0.2%, Ti: 0.2%, Cr: 0.1%, Mo: 0.1%, Zr: 0.1%; the added microalloying elements, by mass percentage, consist of the following components: Bi: 0.15%, Ge: 0.15%; the balance is Al.

[0048] The preparation method of Al-Cu high-strength aluminum alloy materials is as follows: 1) Weigh out A00 standard aluminum, pure Bi, pure Ge, and Al-30%Cu, Al-5%Mn, Al-2%Ti, Al-20%Cr, Al-20%Mo, and Al-5%Zr master alloys according to the mass ratio.

[0049] 2) The raw materials are smelted into aluminum alloy at 760 ℃, then hexachloroethane is pressed into the bell jar to degas the material, and then the slag is removed and refined at 740 ℃. After refining, the material is allowed to stand for 30 min, and then the temperature is lowered to 700 ℃ for casting.

[0050] 3) Before casting, turn on the cooling water in the cold slope casting mold. During casting, the pouring speed should be uniform so that the alloy melt is evenly spread on the cold slope plane (the cold slope copper mold is at a 60° angle to the plane). After the alloy solidifies, immediately water cool it.

[0051] 4) This aluminum alloy material does not require further solution treatment; it can be directly subjected to aging heat treatment at 180 ℃ for 6 h.

[0052] Example 6 An Al-Cu high-strength aluminum alloy material, whose basic elements are composed of the following components by mass percentage: Cu: 4.5%, Mn: 0.4%, Ti: 0.2%, Cr: 0.15%, Mo: 0.15%, Zr: 0.1%; the added microalloying elements are composed of the following components by mass percentage: Bi: 0.1%, Ge: 0.2%; the balance is Al.

[0053] The preparation method of Al-Cu high-strength aluminum alloy materials is as follows: 1) Weigh out A00 standard aluminum, pure Bi, pure Ge, and Al-30%Cu, Al-5%Mn, Al-2%Ti, Al-20%Cr, Al-20%Mo, and Al-5%Zr master alloys according to the mass ratio.

[0054] 2) The raw materials are smelted into aluminum alloy at 760 ℃, then hexachloroethane is pressed into the bell jar to degas the material, and then the slag is removed and refined at 740 ℃. After refining, the material is allowed to stand for 30 min, and then the temperature is lowered to 700 ℃ for casting.

[0055] 3) Before casting, turn on the cooling water in the cold slope casting mold. During casting, the pouring speed should be uniform so that the alloy melt is evenly spread on the cold slope plane (the cold slope copper mold is at a 60° angle to the plane). After the alloy solidifies, immediately water cool it.

[0056] 4) This aluminum alloy material does not require further solution treatment; it can be directly subjected to aging heat treatment at 180 ℃ for 6 h.

[0057] Example 7 An Al-Cu high-strength aluminum alloy material, whose basic elements, by mass percentage, consist of the following components: Cu: 4.7%, Mn: 0.4%, Ti: 0.2%, Cr: 0.15%, Mo: 0.15%, Zr: 0.1%; the added microalloying elements, by mass percentage, consist of the following components: Sb: 0.1%, In: 0.2%; the balance is Al.

[0058] The preparation method of Al-Cu high-strength aluminum alloy materials is as follows: 1) Weigh out A00 standard aluminum, pure Sb, pure In, and Al-30%Cu, Al-5%Mn, Al-2%Ti, Al-20%Cr, Al-20%Mo, and Al-5%Zr master alloys according to the mass ratio.

[0059] 2) The raw materials are smelted into aluminum alloy at 760 ℃, then hexachloroethane is pressed into the bell jar to degas the material, and then the slag is removed and refined at 740 ℃. After refining, the material is allowed to stand for 30 min, and then the temperature is lowered to 700 ℃ for casting.

[0060] 3) Before casting, turn on the cooling water in the cold slope casting mold. During casting, the pouring speed should be uniform so that the alloy melt is evenly spread on the cold slope plane (the cold slope copper mold is at a 60° angle to the plane). After the alloy solidifies, immediately water cool it.

[0061] 4) This aluminum alloy material does not require further solution treatment; it can be directly subjected to aging heat treatment at 180 ℃ for 6 h.

[0062] Example 8 An Al-Cu high-strength aluminum alloy material, whose basic elements, by mass percentage, consist of the following components: Cu: 4.9%, Mn: 0.4%, Ti: 0.25%, Cr: 0.15%, Mo: 0.15%, Zr: 0.15%; the added microalloying elements, by mass percentage, consist of the following components: Sb: 0.15%, In: 0.15%; the balance is Al.

[0063] The preparation method of Al-Cu high-strength aluminum alloy materials is as follows: 1) Weigh out A00 standard aluminum, pure Sb, pure In, and Al-30%Cu, Al-5%Mn, Al-2%Ti, Al-20%Cr, Al-20%Mo, and Al-5%Zr master alloys according to the mass ratio.

[0064] 2) The raw materials are smelted into aluminum alloy at 760 ℃, then hexachloroethane is pressed into the bell jar to degas the material, and then the slag is removed and refined at 740 ℃. After refining, the material is allowed to stand for 30 min, and then the temperature is lowered to 700 ℃ for casting.

[0065] 3) Before casting, turn on the cooling water in the cold slope casting mold. During casting, the pouring speed should be uniform so that the alloy melt is evenly spread on the cold slope plane (the cold slope copper mold is at a 60° angle to the plane). After the alloy solidifies, immediately water cool it.

[0066] 4) This aluminum alloy material does not require further solution treatment; it can be directly subjected to aging heat treatment at 180 ℃ for 6 h.

[0067] Example 9 An Al-Cu high-strength aluminum alloy material, whose basic elements are composed of the following components by mass percentage: Cu: 5.1%, Mn: 0.5%, Ti: 0.25%, Cr: 0.15%, Mo: 0.15%, Zr: 0.15%; the added microalloying elements are composed of the following components by mass percentage: Sn: 0.05%; the balance is Al.

[0068] The preparation method of Al-Cu high-strength aluminum alloy materials is as follows: 1) Weigh out A00 standard aluminum, pure Sn, and Al-30%Cu, Al-5%Mn, Al-2%Ti, Al-20%Cr, Al-20%Mo, and Al-5%Zr master alloys according to the mass ratio.

[0069] 2) The raw materials are smelted into aluminum alloy at 760 ℃, then hexachloroethane is pressed into the bell jar to degas the material, and then the slag is removed and refined at 740 ℃. After refining, the material is allowed to stand for 30 min, and then the temperature is lowered to 700 ℃ for casting.

[0070] 3) Before casting, turn on the cooling water in the cold slope casting mold. During casting, the pouring speed should be uniform so that the alloy melt is evenly spread on the cold slope plane (the cold slope copper mold is at a 60° angle to the plane). After the alloy solidifies, immediately water cool it.

[0071] 4) This aluminum alloy material does not require further solution treatment; it can be directly subjected to aging heat treatment at 180 ℃ for 6 h.

[0072] Example 10 An Al-Cu high-strength aluminum alloy material, whose basic elements are composed of the following components by mass percentage: Cu: 5.3%, Mn: 0.5%, Ti: 0.25%, Cr: 0.15%, Mo: 0.2%, Zr: 0.15%; the added microalloying elements are composed of the following components by mass percentage: Sn: 0.1%; the balance is Al.

[0073] The preparation method of Al-Cu high-strength aluminum alloy materials is as follows: 1) Weigh out A00 standard aluminum, pure Sn, and Al-30%Cu, Al-5%Mn, Al-2%Ti, Al-20%Cr, Al-20%Mo, and Al-5%Zr master alloys according to the mass ratio.

[0074] 2) The raw materials are smelted into aluminum alloy at 760 ℃, then hexachloroethane is pressed into the bell jar to degas the material, and then the slag is removed and refined at 740 ℃. After refining, the material is allowed to stand for 30 min, and then the temperature is lowered to 700 ℃ for casting.

[0075] 3) Before casting, turn on the cooling water in the cold slope casting mold. During casting, the pouring speed should be uniform so that the alloy melt is evenly spread on the cold slope plane (the cold slope copper mold is at a 60° angle to the plane). After the alloy solidifies, immediately water cool it.

[0076] 4) This aluminum alloy material does not require further solution treatment; it can be directly subjected to aging heat treatment at 180 ℃ for 6 h.

[0077] Example 11 An Al-Cu high-strength aluminum alloy material, whose basic elements are composed of the following components by mass percentage: Cu: 5.4%, Mn: 0.6%, Ti: 0.3%, Cr: 0.2%, Mo: 0.2%, Zr: 0.15%; the added microalloying elements are composed of the following components by mass percentage: Sn: 0.15%; the balance is Al.

[0078] The preparation method of Al-Cu high-strength aluminum alloy materials is as follows: 1) Weigh out A00 standard aluminum, pure Sn, and Al-30%Cu, Al-5%Mn, Al-2%Ti, Al-20%Cr, Al-20%Mo, and Al-5%Zr master alloys according to the mass ratio.

[0079] 2) The raw materials are smelted into aluminum alloy at 760 ℃, then hexachloroethane is pressed into the bell jar to degas the material, and then the slag is removed and refined at 740 ℃. After refining, the material is allowed to stand for 30 min, and then the temperature is lowered to 700 ℃ for casting.

[0080] 3) Before casting, turn on the cooling water in the cold slope casting mold. During casting, the pouring speed should be uniform so that the alloy melt is evenly spread on the cold slope plane (the cold slope copper mold is at a 60° angle to the plane). After the alloy solidifies, immediately water cool it.

[0081] 4) This aluminum alloy material does not require further solution treatment; it can be directly subjected to aging heat treatment at 180 ℃ for 6 h.

[0082] Example 12 An Al-Cu high-strength aluminum alloy material, whose basic elements, by mass percentage, consist of the following components: Cu: 5.5%, Mn: 0.7%, Ti: 0.3%, Cr: 0.2%, Mo: 0.2%, Zr: 0.15%; the added microalloying elements, by mass percentage, consist of the following components: Sb: 0.1%, In: 0.1%, Sn: 0.1%; the balance is Al.

[0083] The preparation method of Al-Cu high-strength aluminum alloy materials is as follows: 1) Weigh out A00 standard aluminum, pure Sb, pure In, pure Sn, and Al-30%Cu, Al-5%Mn, Al-2%Ti, Al-20%Cr, Al-20%Mo, and Al-5%Zr master alloys according to the mass ratio.

[0084] 2) The raw materials are smelted into aluminum alloy at 760 ℃, then hexachloroethane is pressed into the bell jar to degas the material, and then the slag is removed and refined at 740 ℃. After refining, the material is allowed to stand for 30 min, and then the temperature is lowered to 700 ℃ for casting.

[0085] 3) Before casting, turn on the cooling water in the cold slope casting mold. During casting, the pouring speed should be uniform so that the alloy melt is evenly spread on the cold slope plane (the cold slope copper mold is at a 60° angle to the plane). After the alloy solidifies, immediately water cool it.

[0086] 4) This aluminum alloy material does not require further solution treatment; it can be directly subjected to aging heat treatment at 180 ℃ for 6 h.

[0087] Example 13 An Al-Cu high-strength aluminum alloy material, whose basic elements are composed of the following components by mass percentage: Cu: 5.8%, Mn: 0.8%, Ti: 0.3%, Cr: 0.2%, Mo: 0.25%, Zr: 0.2%; the added microalloying elements are composed of the following components by mass percentage: Sb: 0.3%; the balance is Al.

[0088] The preparation method of Al-Cu high-strength aluminum alloy materials is as follows: 1) Weigh out A00 standard aluminum, pure Sb, and Al-30%Cu, Al-5%Mn, Al-2%Ti, Al-20%Cr, Al-20%Mo, and Al-5%Zr master alloys according to the mass ratio.

[0089] 2) The raw materials are smelted into aluminum alloy at 760 ℃, then hexachloroethane is pressed into the bell jar to degas the material, and then the slag is removed and refined at 740 ℃. After refining, the material is allowed to stand for 30 min, and then the temperature is lowered to 700 ℃ for casting.

[0090] 3) Before casting, turn on the cooling water in the cold slope casting mold. During casting, the pouring speed should be uniform so that the alloy melt is evenly spread on the cold slope plane (the cold slope copper mold is at a 60° angle to the plane). After the alloy solidifies, immediately water cool it.

[0091] 4) This aluminum alloy material does not require further solution treatment; it can be directly subjected to aging heat treatment at 180 ℃ for 6 h.

[0092] Example 14 An Al-Cu high-strength aluminum alloy material, whose basic elements are composed of the following components by mass percentage: Cu: 6.2%, Mn: 0.8%, Ti: 0.35%, Cr: 0.2%, Mo: 0.25%, Zr: 0.2%; the added microalloying elements are composed of the following components by mass percentage: In: 0.3%; the balance is Al.

[0093] The preparation method of Al-Cu high-strength aluminum alloy materials is as follows: 1) Weigh out A00 standard aluminum, pure In, and Al-30%Cu, Al-5%Mn, Al-2%Ti, Al-20%Cr, Al-20%Mo, and Al-5%Zr master alloys according to the mass ratio.

[0094] 2) The raw materials are smelted into aluminum alloy at 760 ℃, then hexachloroethane is pressed into the bell jar to degas the material, and then the slag is removed and refined at 740 ℃. After refining, the material is allowed to stand for 30 min, and then the temperature is lowered to 700 ℃ for casting.

[0095] 3) Before casting, turn on the cooling water in the cold slope casting mold. During casting, the pouring speed should be uniform so that the alloy melt is evenly spread on the cold slope plane (the cold slope copper mold is at a 60° angle to the plane). After the alloy solidifies, immediately water cool it.

[0096] 4) This aluminum alloy material does not require further solution treatment; it can be directly subjected to aging heat treatment at 180 ℃ for 6 h.

[0097] Example 15 An Al-Cu high-strength aluminum alloy material, whose basic elements, by mass percentage, consist of the following components: Cu: 6.4%, Mn: 0.9%, Ti: 0.35%, Cr: 0.2%, Mo: 0.25%, Zr: 0.2%; the added microalloying elements, by mass percentage, consist of the following components: Bi: 0.2%, Ge: 0.1%; the balance is Al.

[0098] The preparation method of Al-Cu high-strength aluminum alloy materials is as follows: 1) Weigh out A00 standard aluminum, pure Bi, pure Ge, and Al-30%Cu, Al-5%Mn, Al-2%Ti, Al-20%Cr, Al-20%Mo, and Al-5%Zr master alloys according to the mass ratio.

[0099] 2) The raw materials are smelted into aluminum alloy at 760 ℃, then hexachloroethane is pressed into the bell jar to degas the material, and then the slag is removed and refined at 740 ℃. After refining, the material is allowed to stand for 30 min, and then the temperature is lowered to 700 ℃ for casting.

[0100] 3) Before casting, turn on the cooling water in the cold slope casting mold. During casting, the pouring speed should be uniform so that the alloy melt is evenly spread on the cold slope plane (the cold slope copper mold is at a 60° angle to the plane). After the alloy solidifies, immediately water cool it.

[0101] 4) This aluminum alloy material does not require further solution treatment; it can be directly subjected to aging heat treatment at 180 ℃ for 6 h.

[0102] Example 16 An Al-Cu high-strength aluminum alloy material, whose basic elements, by mass percentage, consist of the following components: Cu: 6.5%, Mn: 0.9%, Ti: 0.35%, Cr: 0.2%, Mo: 0.25%, Zr: 0.2%; the added microalloying elements, by mass percentage, consist of the following components: In: 0.2%, Sn: 0.1%; the balance is Al.

[0103] The preparation method of Al-Cu high-strength aluminum alloy materials is as follows: 1) Weigh out A00 standard aluminum, pure In, pure Sn, and Al-30%Cu, Al-5%Mn, Al-2%Ti, Al-20%Cr, Al-20%Mo, and Al-5%Zr master alloys according to the mass ratio.

[0104] 2) The raw materials are smelted into aluminum alloy at 760 ℃, then hexachloroethane is pressed into the bell jar to degas the material, and then the slag is removed and refined at 740 ℃. After refining, the material is allowed to stand for 30 min, and then the temperature is lowered to 700 ℃ for casting.

[0105] 3) Before casting, turn on the cooling water in the cold slope casting mold. During casting, the pouring speed should be uniform so that the alloy melt is evenly spread on the cold slope plane (the cold slope copper mold is at a 60° angle to the plane). After the alloy solidifies, immediately water cool it.

[0106] 4) This aluminum alloy material does not require further solution treatment; it can be directly subjected to aging heat treatment at 180 ℃ for 6 h.

[0107] Example 17 An Al-Cu high-strength aluminum alloy material, whose basic elements, by mass percentage, consist of the following components: Cu: 6.8%, Mn: 1.0%, Ti: 0.35%, Cr: 0.2%, Mo: 0.25%, Zr: 0.2%; the added microalloying elements, by mass percentage, consist of the following components: Sb: 0.2%, Sn: 0.1%; the balance is Al.

[0108] The preparation method of Al-Cu high-strength aluminum alloy materials is as follows: 1) Weigh out A00 standard aluminum, pure Sb, pure Sn, and Al-30%Cu, Al-5%Mn, Al-2%Ti, Al-20%Cr, Al-20%Mo, and Al-5%Zr master alloys according to the mass ratio.

[0109] 2) The raw materials are smelted into aluminum alloy at 760 ℃, then hexachloroethane is pressed into the bell jar to degas the material, and then the slag is removed and refined at 740 ℃. After refining, the material is allowed to stand for 30 min, and then the temperature is lowered to 700 ℃ for casting.

[0110] 3) Before casting, turn on the cooling water in the cold slope casting mold. During casting, the pouring speed should be uniform so that the alloy melt is evenly spread on the cold slope plane (the cold slope copper mold is at a 60° angle to the plane). After the alloy solidifies, immediately water cool it.

[0111] 4) This aluminum alloy material does not require further solution treatment; it can be directly subjected to aging heat treatment at 180 ℃ for 6 h.

[0112] Example 18 An Al-Cu high-strength aluminum alloy material, whose basic elements are composed of the following components by mass percentage: Cu: 6.9%, Mn: 1.0%, Ti: 0.35%, Cr: 0.2%, Mo: 0.25%, Zr: 0.2%; the added microalloying elements are composed of the following components by mass percentage: Bi: 0.3%; the balance is Al.

[0113] The preparation method of Al-Cu high-strength aluminum alloy materials is as follows: 1) Weigh out A00 standard aluminum, pure Bi, and master alloys of Al-30%Cu, Al-5%Mn, Al-2%Ti, Al-20%Cr, Al-20%Mo, and Al-5%Zr according to the mass ratio.

[0114] 2) The raw materials are smelted into aluminum alloy at 760 ℃, then hexachloroethane is pressed into the bell jar to degas the material, and then the slag is removed and refined at 740 ℃. After refining, the material is allowed to stand for 30 min, and then the temperature is lowered to 700 ℃ for casting.

[0115] 3) Before casting, turn on the cooling water in the cold slope casting mold. During casting, the pouring speed should be uniform so that the alloy melt is evenly spread on the cold slope plane (the cold slope copper mold is at a 60° angle to the plane). After the alloy solidifies, immediately water cool it.

[0116] 4) This aluminum alloy material does not require further solution treatment; it can be directly subjected to aging heat treatment at 180 ℃ for 6 h.

[0117] Example 19 An Al-Cu high-strength aluminum alloy material, whose basic elements are composed of the following components by mass percentage: Cu: 7.1%, Mn: 1.0%, Ti: 0.35%, Cr: 0.2%, Mo: 0.25%, Zr: 0.2%; the added microalloying elements are composed of the following components by mass percentage: Ge: 0.3%; the balance is Al.

[0118] The preparation method of Al-Cu high-strength aluminum alloy materials is as follows: 1) Weigh out A00 standard aluminum, pure Ge, and master alloys of Al-30%Cu, Al-5%Mn, Al-2%Ti, Al-20%Cr, Al-20%Mo, and Al-5%Zr according to the mass ratio.

[0119] 2) The raw materials are smelted into aluminum alloy at 760 ℃, then hexachloroethane is pressed into the bell jar to degas the material, and then the slag is removed and refined at 740 ℃. After refining, the material is allowed to stand for 30 min, and then the temperature is lowered to 700 ℃ for casting.

[0120] 3) Before casting, turn on the cooling water in the cold slope casting mold. During casting, the pouring speed should be uniform so that the alloy melt is evenly spread on the cold slope plane (the cold slope copper mold is at a 60° angle to the plane). After the alloy solidifies, immediately water cool it.

[0121] 4) This aluminum alloy material does not require further solution treatment; it can be directly subjected to aging heat treatment at 180 ℃ for 6 h.

[0122] Comparative Example 1 In this comparative example, a casting method combined with the traditional T6 heat treatment process was used. The basic elements consist of the following raw material mass ratios: Cu: 5.3%, Mn: 0.5%, Ti: 0.25%, Cr: 0.15%, Mo: 0.2%, Zr: 0.15%; the added microalloying elements consist of the following raw material mass ratios: Sn: 0.1%; the balance is Al. This composition is exactly the same as that of Example 10 of this invention.

[0123] The preparation method of Al-Cu high-strength aluminum alloy materials is as follows: 1) Weigh out A00 standard aluminum, pure Sn, and Al-30%Cu, Al-5%Mn, Al-2%Ti, Al-20%Cr, Al-20%Mo, and Al-5%Zr master alloys according to the mass ratio.

[0124] 2) The raw materials are smelted into aluminum alloy at 760 °C, then hexachloroethane is pressed into the bell jar to degas the material, and then the slag is removed and refined at 740 °C. After refining, the material is allowed to stand for 30 minutes, and then the temperature is lowered to 700 °C for casting.

[0125] 3) The casting adopts traditional metal mold (not cold-slope copper mold), and is air-cooled to room temperature after casting.

[0126] 4) The solidified alloy was solution treated at 540°C for 15 hours, quenched in water, and then aged at 180°C for 6 hours.

[0127] Comparative Example 2 In this comparative example, an Al-Cu aluminum alloy material is composed of the following raw material mass ratios: Cu: 5.3%, Mn: 0.5%, Ti: 0.25%, Cr: 0.15%, Mo: 0.2%, Zr: 0.15%; no microalloying elements are added; the balance is Al. This basic composition is the same as that of Example 10 of the present invention, but the microalloying element Sn is deliberately omitted.

[0128] The preparation method of Al-Cu high-strength aluminum alloy materials is as follows: 1) Weigh out A00 standard aluminum and Al-30%Cu, Al-5%Mn, Al-2%Ti, Al-20%Cr, Al-20%Mo, and Al-5%Zr master alloys according to the mass ratio.

[0129] 2) The raw materials are smelted into aluminum alloy at 760 °C, then hexachloroethane is pressed into the bell jar to degas the material, and then the slag is removed and refined at 740 °C. After refining, the material is allowed to stand for 30 minutes, and then the temperature is lowered to 700 °C for casting.

[0130] 3) Before casting, turn on the cooling condensate in the cold slope casting mold. During casting, the pouring speed should be uniform so that the alloy melt is evenly spread on the cold slope surface. After the alloy solidifies, immediately perform water quenching.

[0131] 4) This aluminum alloy material does not require further solution treatment; it can be directly subjected to aging heat treatment at 180 °C for 6 hours.

[0132] Comparative Example 3 In this comparative example, an Al-Cu aluminum alloy material is composed of the following raw material mass ratios: Cu: 5.3%, Fe: 0.45% (intentionally exceeded), Ti: 0.25%, Zr: 0.15%; no Fe element modifiers such as Mn, Cr, and Mo are added; no microalloying elements are added; the balance is Al. This comparative example aims to simulate the situation in the prior art where Fe impurities are not strictly controlled and no effective modification measures are taken.

[0133] The preparation method of Al-Cu high-strength aluminum alloy materials is as follows: 1) Weigh out A00 standard aluminum and Al-30%Cu, Al-2%Ti, and Al-5%Zr master alloys according to the mass ratio, and add Al-5%Fe master alloy to achieve high iron content; 2) The raw materials are smelted into aluminum alloy at 760 °C, then hexachloroethane is pressed into the bell jar to degas the material, and then the slag is removed and refined at 740 °C. After refining, the material is allowed to stand for 30 minutes, and then the temperature is lowered to 700 °C for casting.

[0134] 3) Before casting, turn on the cooling condensate in the cold slope casting mold. During casting, the pouring speed should be uniform so that the alloy melt is evenly spread on the cold slope surface. After the alloy solidifies, immediately perform water quenching.

[0135] 4) This aluminum alloy material does not require further solution treatment; it can be directly subjected to aging heat treatment at 180 °C for 6 hours.

[0136] According to GB / T228.1-2010 standard, samples were taken for tensile property testing, and the test results are shown in Table 1.

[0137] Table 1: Results of Room Temperature Mechanical Properties Tests for Examples

[0138] As shown in Table 1, considering tensile strength, yield strength, and elongation, Example 10 exhibits the best results. The mechanical strength of the prepared aluminum alloy material generally increases with the increase of the content of the main alloying element Cu, but this increase is not simple and linear; the mechanical properties of the alloy are also greatly influenced by the added microalloying elements. Analysis of the above data shows that the mechanical strength of the alloy is higher when different microalloying elements are added in combination, and the effect of combined addition is better than that of single addition. Furthermore, the assisted precipitation effect of Sn and In elements is better than that of other microalloying elements. The aluminum alloy material prepared by this invention shows a significant improvement in mechanical properties compared to currently available aluminum alloy materials with similar compositions.

[0139] As can be seen from the mechanical property data of the comparative examples in Table 1, although Comparative Example 1 (traditional T6 process) used the same composition as Example 10, the use of traditional casting with a slow cooling rate resulted in coarse grains, and the high-temperature solution treatment further induced grain growth. Its strength and plasticity were significantly lower than those of Example 10, which used the cold-slope casting short-process technology of this invention. This proves that the short-process technology of this invention is superior to the traditional long-process technology in terms of performance. Comparative Example 2 (without microalloying elements) used the cold-slope casting short-process technology of this invention, but due to the lack of the microalloying element Sn, its tensile strength and yield strength both decreased significantly. This proves that the microalloying element plays an indispensable auxiliary precipitation role in achieving peak strength in the short-process technology. Comparative Example 3 (high Fe and no modifying elements) had the worst mechanical properties, especially a sharp decrease in elongation. This indicates that even with a rapid cooling process, if Fe impurities exceed the standard and are not modified by Mn, Cr, and Mo elements, a large number of needle-like harmful phases will form in the alloy, severely rupturing the matrix, leading to deterioration of the alloy's plasticity and toughness, and a significant decrease in strength. This demonstrates the necessity and superiority of the component design in this invention, which involves "strictly controlling the Fe content and adding Mn, Cr, and Mo for synergistic degradation".

[0140] In summary, the superior mechanical properties of this invention are the result of the synergistic and inseparable effects of specific compositional design (including microalloying elements and Fe modification elements) and the short-process cold-slope casting. The absence of either aspect would prevent the achievement of the technical effects of this invention.

[0141] 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. An Al-Cu based high-strength aluminum alloy, characterized in that, The basic alloying elements include the following mass fractions: Cu: 2.9~7.1%, Mn: 0.15~1.0%, Ti: 0.1~0.35%, Cr: 0.05~0.2%, Mo: 0.05~0.25%, Zr: 0.05~0.2%; It also includes at least one of the following microalloying auxiliary elements by mass fraction: Sb: 0~0.3%, In: 0~0.3%, Sn: 0~0.15%, Bi: 0~0.3%, Ge: 0~0.3%; the balance being Al.

2. The Al-Cu high-strength aluminum alloy according to claim 1, characterized in that, Among the microalloying auxiliary elements, 0.05%≤Sb+In+Sn≤0.3% or 0.05%≤Bi+Ge≤0.3%.

3. The Al-Cu high-strength aluminum alloy according to claim 1, characterized in that, Impurity content control: Fe≤0.15%, Si≤0.05%, Mg≤0.05%, and the total amount of other impurities≤0.3%.

4. A method for preparing an Al-Cu high-strength aluminum alloy according to any one of claims 1-3, characterized in that, The alloy raw materials after batching are melted, and a refining agent is added for slag removal and refining. After standing, the mixture is cast onto a steep-slope mold to obtain an alloy casting. The alloy casting is then subjected to aging treatment in sequence to obtain the final product.

5. The method for preparing Al-Cu high-strength aluminum alloy according to claim 4, characterized in that, The melting temperature is 700~800 ℃; the refining agent is hexachloroethane (C2Cl6); the refining temperature is 740~750 ℃.

6. The method for preparing Al-Cu high-strength aluminum alloy according to claim 4, characterized in that, The settling time is 10-30 minutes; the casting temperature is 690-710 ℃.

7. The method for preparing Al-Cu high-strength aluminum alloy according to claim 4, characterized in that, The steep slope mold has an inclination angle of 60~70°, and a cooling medium is introduced into the steep slope mold; the thickness of the alloy casting is ≤10 mm.

8. The method for preparing Al-Cu high-strength aluminum alloy according to claim 4, characterized in that, The aging strengthening treatment is performed at a temperature of 150~200 ℃ for 5~10 h.

9. The method for preparing Al-Cu high-strength aluminum alloy according to claim 4, characterized in that, The purity of the alloy raw material is >99%.

10. The application of the Al-Cu high-strength aluminum alloy according to any one of claims 1-3 in the fields of aerospace, automobile, petroleum equipment and electronics.

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