Method for producing high-strength aluminium-copper alloy

Abstract

A high-strength and high-toughness aluminum-copper alloy is characterized by the following mass percentage composition: Cu: 5-7%, Mn: 0.3-0.5%, Cd: 0.15-0.25%, Ti: 0.15-0.35%, Zr: 0.15-0.25%, V: 0.05-0.3%, with the balance being Al and unavoidable impurities. This invention also discloses a method for preparing this aluminum-copper alloy. Through compositional design and process optimization, the high-strength and high-toughness aluminum-copper alloy obtained by this invention has a tensile strength ≥500MPa, elongation after fracture ≥10%, casting fluidity sample length ≥900mm, and hot crack ring width ≤12.5mm. The comprehensive performance of the aluminum-copper alloy obtained by this invention is far superior to that of conventional aluminum-copper alloys.

Description

Technical Field

[0001] This invention relates to an alloy, particularly to an aluminum-copper alloy, and also to a method for preparing the aluminum-copper alloy. Background Technology

[0002] Aluminum-copper alloys possess high strength, high toughness, and fatigue resistance, making them potential high-performance structural materials. However, due to their wide solidification temperature range, significant linear shrinkage in the mushy region, and poor casting fluidity, complex aluminum-copper castings are prone to casting defects such as porosity and hot cracking. This limits their application in complex components and makes it difficult to meet the casting process requirements of large and complex components. Therefore, it is urgent to address the bottlenecks restricting the application of high-performance aluminum-copper alloys in complex components by focusing on material design, material strengthening theory, forming methods, and processes. Summary of the Invention

[0003] The first technical problem to be solved by the present invention is to provide a high-strength and high-toughness aluminum-copper alloy with good casting fluidity and low tendency to hot cracking, in view of the above-mentioned technical status.

[0004] The second technical problem to be solved by the present invention is to provide a method for preparing a high-strength and high-toughness aluminum-copper alloy with good casting fluidity and low tendency to hot cracking, in view of the above-mentioned technical status.

[0005] The technical solution adopted by the present invention to solve the first technical problem mentioned above is as follows: a high-strength and high-toughness aluminum-copper alloy, characterized in that the mass percentage composition of the aluminum-copper alloy is as follows: Cu: 5~7%, Mn: 0.3~0.5%, Cd: 0.15~0.25%, Ti: 0.15~0.35%, Zr: 0.15~0.25%, V: 0.05~0.3%, with the balance being Al and unavoidable impurities. The microstructure of the aluminum-copper alloy consists of an α-Al matrix, an Al2Cu phase, and an Al... 20 It is composed of Cu2Mn3 phase, Al3Ti phase, Al3Zr phase and Cd phase. Among them, the average size of Al2Cu(θ') phase is 30~40nm, the average grain size in the as-cast state is 100~110μm, the average grain size in the T6 state is 90~100μm, and the grains are equiaxed.

[0006] Preferably, the aluminum-copper alloy has the following mass percentage composition: Cu: 6%, Mn: 0.4%, Cd: 0.2%, Ti: 0.15%, Zr: 0.15%, V: 0.15%, with the balance being Al and unavoidable impurities.

[0007] Preferably, the aluminum-copper alloy has the following mass percentage composition: Cu: 6.5%, Mn: 0.3%, Cd: 0.15%, Ti: 0.2%, Zr: 0.2%, V: 0.2%, with the balance being Al and unavoidable impurities.

[0008] The technical solution adopted by the present invention to solve the second technical problem mentioned above is: a method for preparing a high-strength and high-toughness aluminum-copper alloy, characterized by comprising the following steps:

[0009] ① Ingredients: Weigh and mix aluminum ingots, pure cadmium ingots, aluminum-copper alloys, aluminum-manganese alloys, aluminum-titanium alloys, aluminum-zirconium alloys, aluminum-vanadium alloys and other raw materials in proportion to prepare aluminum-copper alloys.

[0010] ② Smelting: First, aluminum ingots, aluminum-copper alloys, and aluminum-manganese alloys are placed in a crucible. After melting, pure cadmium ingots, aluminum-titanium alloys, aluminum-zirconium alloys, and aluminum-vanadium alloys are added to refine the aluminum liquid once. Then, TiB2 particles with a weight percentage of 0.1~0.5% are added in the form of Al-TiB2 master alloy. The mixture is stirred evenly and then refined a second time by vacuum degassing. After standing, aluminum-copper alloy melt is obtained.

[0011] ③ Casting: The obtained aluminum-copper alloy melt is slowly poured into a mold to obtain an aluminum-copper alloy ingot;

[0012] ④ Heat treatment: The obtained aluminum-copper alloy ingots are subjected to solution treatment and aging treatment.

[0013] As a preferred option, the melting temperature in step ② is controlled as follows: first, aluminum ingots, aluminum-copper alloys, and aluminum-manganese alloys are placed in a crucible and the temperature is set to 750~800℃. After melting, pure cadmium ingots, aluminum-titanium alloys, aluminum-zirconium alloys, and aluminum-vanadium alloys are added, and the temperature is lowered to 720~770℃.

[0014] Preferably, in step ②, a rotary jet blowing device is used to blow N2 for a primary refining process.

[0015] Preferably, the pouring temperature in step ③ is 710~760℃.

[0016] As a preferred embodiment, the solution treatment conditions in step ④ are as follows:

[0017] The first-stage solution treatment temperature is 500~520℃, and the time is 6~8 hours;

[0018] The secondary solution treatment temperature is 530~560℃, and the time is 6~8h.

[0019] As a preferred option, the aging process conditions in step ④ are as follows:

[0020] The single-stage aging temperature is 150~200℃, and the time is 4~6h.

[0021] Compared with the prior art, the advantages of the present invention are: Cu and Mn elements react with Al to form Al2Cu and Al2Cu. 20Strengthening phases such as Cu2Mn3 improve material properties; Ti, Zr, and V elements act as grain refiners, forming phases such as Al3Ti and Al3Zr in the microstructure, which serve as heterogeneous nucleation sites for α-Al, promoting efficient nucleation and achieving the effect of grain refinement and strengthening; Cd elements can not only form elemental Cd phase, but also improve the size and distribution of Al2Cu(θ') phase.

[0022] The introduction of in-situ TiB2 particles promotes heterogeneous nucleation in the aluminum-copper alloy, generating nanoscale TiB2 particles in situ within the matrix that act as a nucleation substrate for α-Al growth. Simultaneously, during alloy cooling and solidification, the TiB2 particles pinnate at the grain boundaries of the α-Al phase, preventing solute diffusion and effectively inhibiting α-Al grain growth, thus refining the microstructure. Furthermore, the addition of these micro / nano particles hinders dendrite growth in the aluminum-copper alloy. Heterogeneous nucleation significantly increases the number of dendrite nucleation points, and the competitive growth of dendrites reduces dendrite size, refines the grains, and delays dendrite overlap time, aiding in solidification and feeding. Some micro / nano particles also fill the interdendritic gaps, thereby improving fluidity and reducing hot cracking tendency, porosity, and shrinkage cavities.

[0023] This invention, through composition design and process optimization, yields a high-strength and high-toughness aluminum-copper alloy with a tensile strength ≥500MPa, elongation after fracture ≥10%, casting fluidity sample length ≥900mm, and hot crack ring width ≤12.5mm. Its overall performance far surpasses that of conventional aluminum-copper alloys. Attached Figure Description

[0024] Figure 1 The image shows the as-cast microstructure of the aluminum-copper alloy in Example 1 (200x magnification).

[0025] Figure 2 The image shows the microstructure of the aluminum-copper alloy in the T6 state in Example 1 (200x magnification). Detailed Implementation

[0026] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0027] Example 1:

[0028] ① Batching: Weigh and mix raw materials such as aluminum ingots, pure cadmium ingots, aluminum-copper alloys, aluminum-manganese alloys, aluminum-titanium alloys, aluminum-zirconium alloys, and aluminum-vanadium alloys in the proportion of 6% Cu, 0.4% Mn, 0.2% Cd, 0.15% Ti, 0.15% Zr, and 0.15% V to prepare aluminum-copper alloys.

[0029] ② Smelting: First, aluminum ingots, aluminum-copper alloys, and aluminum-manganese alloys are placed in a crucible, and the temperature is set to 750℃. After melting, pure cadmium ingots, aluminum-titanium alloys, aluminum-zirconium alloys, and aluminum-vanadium alloys are added. The temperature is lowered to 730℃, and the aluminum liquid is refined by blowing N2 through a rotary jet device for 12 minutes, followed by skimming off the slag. Subsequently, 0.1% by weight of TiB2 particles are added in the form of an Al-TiB2 master alloy, stirred evenly, and then refined a second time by vacuum degassing. After standing for 15 minutes, a high-strength and high-toughness aluminum-copper alloy melt is obtained.

[0030] ③ Casting: The obtained aluminum alloy melt is slowly poured into a mold to obtain an aluminum-copper alloy ingot. The pouring temperature is 720℃.

[0031] ④ Heat treatment: The obtained aluminum-copper alloy ingot is subjected to solution treatment and aging treatment. A two-stage solution treatment of 515℃×6h+535℃×8h and a single-stage aging treatment of 170℃×4h are used. The final product is a high-strength and high-toughness aluminum-copper alloy casting blank.

[0032] like Figure 1 and Figure 2 The images shown are photographs of the as-cast microstructure and the T6 state microstructure of the aluminum-copper alloy in this embodiment. The high-strength and high-toughness aluminum-copper alloy obtained in this embodiment has a tensile strength of 510 MPa, an elongation after fracture of 12%, a casting fluidity sample length of 1000 mm, and a hot crack ring width of 12.5 mm.

[0033] Example 2:

[0034] ① Ingredients: Weigh and mix aluminum ingots, pure cadmium ingots, aluminum-copper alloys, aluminum-manganese alloys, aluminum-titanium alloys, aluminum-zirconium alloys, aluminum-vanadium alloys, etc., in the proportion of 6.5% Cu, 0.3% Mn, 0.15% Cd, 0.2% Ti, 0.2% Zr, and 0.2% V to prepare aluminum-copper alloys.

[0035] ② Smelting: First, aluminum ingots, aluminum-copper alloys, and aluminum-manganese alloys are placed in a crucible, and the temperature is set to 780℃. After melting, pure cadmium ingots, aluminum-titanium alloys, aluminum-zirconium alloys, and aluminum-vanadium alloys are added. The temperature is lowered to 760℃, and the aluminum liquid is refined by blowing N2 through a rotary jet device for 15 minutes, followed by skimming off the slag. Subsequently, 0.2% by weight of TiB2 particles are added in the form of an Al-TiB2 master alloy, stirred evenly, and then refined a second time by vacuum degassing. After standing for 15 minutes, a high-strength and high-toughness aluminum-copper alloy melt is obtained.

[0036] ③ Casting: The obtained aluminum alloy melt is slowly poured into a mold to obtain an aluminum-copper alloy ingot. The pouring temperature is 750℃.

[0037] ④ Heat treatment: The obtained aluminum-copper alloy ingot is subjected to solution treatment and aging treatment. A two-stage solution treatment of 510℃×6h+540℃×8h and a single-stage aging treatment of 180℃×4h are used. The final product is a high-strength and high-toughness aluminum-copper alloy casting blank.

[0038] The high-strength and high-toughness aluminum-copper alloy obtained in this embodiment has a tensile strength of 500 MPa, an elongation after fracture of 10%, a casting fluidity sample length of 900 mm, and a hot crack ring width of 12.5 mm. Its overall performance is far superior to that of conventional aluminum-copper alloys.

Claims

1. A method for preparing a high-strength and high-toughness aluminum-copper alloy, characterized in that, Includes the following steps: ①Ingredients: Weigh and mix aluminum ingots, pure cadmium ingots, aluminum-copper alloy, aluminum-manganese alloy, aluminum-titanium alloy, aluminum-zirconium alloy, and aluminum-vanadium alloy raw materials in proportion to prepare aluminum-copper alloy. ② Smelting: First, aluminum ingots, aluminum-copper alloys, and aluminum-manganese alloys are placed in a crucible. After melting, pure cadmium ingots, aluminum-titanium alloys, aluminum-zirconium alloys, and aluminum-vanadium alloys are added to refine the aluminum liquid once. Then, TiB2 particles with a weight percentage of 0.1~0.5% are added in the form of Al-TiB2 master alloy. The mixture is stirred evenly and then refined a second time by vacuum degassing. After standing, aluminum-copper alloy melt is obtained. ③ Casting: The obtained aluminum-copper alloy melt is slowly poured into a mold to obtain an aluminum-copper alloy ingot; ④ Heat treatment: The obtained aluminum-copper alloy ingots are subjected to solution treatment and aging treatment; The aluminum-copper alloy obtained in step ④ has the following mass percentage composition: Cu: 5~7%, Mn: 0.3~0.5%, Cd: 0.15~0.25%, Ti: 0.15~0.35%, Zr: 0.15~0.25%, V: 0.05~0.3%, with the balance being Al and unavoidable impurities. The microstructure of this aluminum-copper alloy consists of an α-Al matrix, an Al2Cu phase, and an Al... 20 It is composed of Cu2Mn3 phase, Al3Ti phase, Al3Zr phase and Cd phase. Among them, the average size of Al2Cu(θ') phase is 30~40nm, the average grain size in the as-cast state is 100~110μm, the average grain size in the T6 state is 90~100μm, and the grains are equiaxed. In step ②, a rotary jet blowing device is used to blow N2 for a primary refining process; The solution treatment conditions in step ④ are as follows: The first-stage solution treatment temperature is 500~520℃, and the time is 6~8 hours; The secondary solution treatment temperature is 530~560℃, and the time is 6~8h; The timeliness processing conditions in step ④ are as follows: The single-stage aging temperature is 150~200℃, and the time is 4~6h.

2. The preparation method according to claim 1, characterized in that, The mass percentage composition of this aluminum-copper alloy is as follows: Cu: 6%, Mn: 0.4%, Cd: 0.2%, Ti: 0.15%, Zr: 0.15%, V: 0.15%, with the balance being Al and unavoidable impurities.

3. The preparation method according to claim 1, characterized in that, The mass percentage composition of this aluminum-copper alloy is as follows: Cu: 6.5%, Mn: 0.3%, Cd: 0.15%, Ti: 0.2%, Zr: 0.2%, V: 0.2%, with the balance being Al and unavoidable impurities.

4. The preparation method according to claim 1, characterized in that, The melting temperature control in step ② is as follows: First, put aluminum ingots, aluminum-copper alloys, and aluminum-manganese alloys into a crucible and set the temperature to 750~800℃. After melting, add pure cadmium ingots, aluminum-titanium alloys, aluminum-zirconium alloys, and aluminum-vanadium alloys, and cool down to 720~770℃.

5. The preparation method according to claim 1, characterized in that, In step ③, the pouring temperature during casting is 710~760℃.

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