Two types of nanoparticle-reinforced Al-Cu binary alloys and their preparation methods

Abstract

A two-type nanoparticle-reinforced Al-Cu binary alloy and its preparation method are disclosed. The preparation method includes the following steps: A) Prepare a cast Al-Cu binary alloy with a mass percentage of 2-10% Cu, unavoidable impurity element content ≤0.1%, and the remainder being Al; B) Anneal the cast Al-Cu binary alloy; C) Hold the Al-Cu binary alloy at 300-450℃ for 2-4 hours, and then perform hot extrusion at a temperature of 300-450℃, an extrusion speed of 0.1-5 mm / s, and an extrusion ratio of 9-30:1. D. Place the Al-Cu binary alloy in a heat treatment furnace and heat it to 530-630℃ for semi-solid isothermal treatment, holding it at that temperature for 0.1-3 hours, followed by water quenching. E. Hold the Al-Cu binary alloy at 150-250℃ for 0.5-2 hours, then perform a secondary extrusion at a temperature of 150-250℃, an extrusion speed of 0.1-5 mm / s, and an extrusion ratio of 9-30:1 to obtain a nanoparticle-reinforced Al-Cu binary alloy. F. Perform aging treatment on the nanoparticle-reinforced Al-Cu binary alloy to obtain the final product. The Al-Cu binary alloy prepared by the above method possesses excellent yield strength, tensile strength, and elongation.

Description

Technical Field

[0001] This invention relates to two types of nanoparticle-reinforced Al-Cu binary alloys and their preparation methods, belonging to the field of aluminum alloy manufacturing. Background Technology

[0002] Aluminum alloys are widely used in transportation, defense, aerospace, and shipbuilding due to their low density, good formability, excellent corrosion resistance, and oxidation resistance. To meet engineering requirements, alloying elements (such as zinc, magnesium, copper, manganese, titanium, and silicon) are often added to improve the strength of aluminum alloys. The series of strengthening effects produced by these elements (such as solid solution strengthening, precipitation strengthening, second-phase strengthening, and grain refinement) further expand the application range of aluminum alloys. In addition, the interaction between deformation strengthening and alloying is also an important means of developing high-strength and high-toughness aluminum alloys.

[0003] 2xxx series aluminum alloys, as one of the traditional heat-treatable hard aluminum alloys, often involve adding Cu and Mg elements to precipitate Al2Cu and Al2CuMg phases, while a small amount of Mn element forms dispersed Al during annealing. 20 The Cu2Mn3 strengthening phase and the interaction between its evolution and alloy deformation behavior are key factors in improving the strength of 2xxx aluminum alloys. Al-Cu binary alloys, as the base alloys of the 2xxx series aluminum alloys, lack the strengthening properties of alloying elements such as Mg, Mn, and Ti, resulting in relatively low strength and limited industrial applications. Therefore, developing novel processing techniques to achieve stable performance improvements in Al-Cu binary alloys without adding other alloying elements is of great significance for the research and development of high-strength 2xxx aluminum alloys.

[0004] Currently, Al-Cu binary alloys primarily rely on micron-sized Al2Cu particles obtained through hot extrusion and the nanophase precipitated during T6 treatment for second-phase strengthening and precipitation strengthening. However, existing deformation techniques struggle to further refine the size of Al2Cu particles. To obtain Al-Cu alloys with excellent mechanical properties, existing methods can control the size and quantity of the precipitated phase by adjusting solid solution aging parameters, thereby compensating for the adverse effects of micron-sized Al2Cu particles on alloy strength. In practical applications, aluminum alloys are required to possess excellent comprehensive mechanical properties; therefore, developing high-performance aluminum alloys with superior yield strength, tensile strength, and elongation is an urgent problem to be solved. Summary of the Invention

[0005] The purpose of this invention is to provide two types of nanoparticle-reinforced Al-Cu binary alloys and their preparation methods. The Al-Cu binary alloys obtained by this method are reinforced by two types of nanoparticles: eutectic fragmented Al2Cu nanoparticles and precipitated nano-θ' phases. The prepared Al-Cu binary alloys possess excellent yield strength, tensile strength, and elongation.

[0006] The technical solution adopted by this invention to achieve its objective is: a two-type nanoparticle-reinforced Al-Cu binary alloy and its preparation method, wherein the two types of nanoparticles are eutectic fragmented nano-Al2Cu particles and precipitated nano-θ' phase, and the preparation method steps are as follows:

[0007] A. Prepare a cast Al-Cu binary alloy according to the set mass percentage of each component element; the set mass percentage of each component element is: 2-10% Cu, unavoidable impurity element content ≤0.1%, and the remainder is Al;

[0008] B. Anneal the as-cast Al-Cu binary alloy prepared in step A;

[0009] C. After holding the annealed Al-Cu binary alloy obtained in step B at 300-450℃ for 2-4 hours, hot extrusion is carried out. The extrusion temperature is 300-450℃, the extrusion speed is 0.1-5mm / s, and the extrusion ratio is 9-30:1.

[0010] D. Place the hot-extruded Al-Cu binary alloy obtained in step C into a heat treatment furnace, heat it to 530-630℃ with the furnace for semi-solid isothermal treatment, hold it for 0.1-3 hours, and then water-quench it.

[0011] E. After holding the Al-Cu binary alloy obtained in step D at 150-250℃ for 0.5-2h, it is then subjected to secondary extrusion to obtain nanoparticle-reinforced Al-Cu binary alloy; the extrusion temperature of the secondary extrusion is 150-250℃, the extrusion speed is 0.1-5mm / s, and the extrusion ratio is 9-30:1.

[0012] F. Aging treatment is performed on the nanoparticle-reinforced Al-Cu binary alloy obtained in step E to obtain two types of nanoparticle-reinforced Al-Cu binary alloys.

[0013] The reaction principle of this invention is as follows: The as-cast Al-Cu binary alloy obtained in step A has a eutectic phase morphology of micron-level lamellar spacing (α-Al + Al2Cu), with the eutectic phase Al2Cu mostly distributed in lamellar eutectic form between the pre-solidified α-Al dendrites. After annealing in step B and hot extrusion in step C, the micron-level eutectic structure is broken into micron-level Al2Cu particles. Then, step D transforms the micron-level Al2Cu particles into a nanon-level eutectic (α-Al + Al2Cu) structure. The eutectic structure (+Al2Cu) is broken down into nanoscale Al2Cu particles after secondary extrusion in step E, and dispersed on the α-Al matrix. Finally, the aging treatment in step F causes a large amount of θ' phase to precipitate. The combined effect of the dispersed Al2Cu nanoparticles and the large amount of precipitated θ' phase significantly improves the strength of the Al-Cu binary alloy, resulting in two types of nanoparticle-reinforced Al-Cu binary alloys with excellent performance and low cost, which also have excellent yield strength, tensile strength and elongation.

[0014] Compared with the prior art, the beneficial effects of the present invention are:

[0015] First, the mass percentage of constituent elements set in step A can prepare an Al-Cu binary alloy containing interdendritic lamellar eutectic (α-Al+Al2Cu). This ensures that through subsequent processing steps B, C, and D, nanoscale eutectic (α-Al+Al2Cu) with a lamellar spacing of less than 100 nm can be obtained in the Al-Cu binary alloy. At the same time, the absence of other strengthening alloying elements greatly simplifies the alloy preparation process and reduces the alloy preparation cost.

[0016] Second, the annealing treatment in step B removes stress from the alloy, improving its deformability and workability. The subsequent hot extrusion treatment in step C yields a particle-reinforced Al-Cu binary alloy with micron-sized Al2Cu particles. Experiments have verified that the hot extrusion parameters in step C result in more uniform lamellar thickness in the subsequently prepared semi-solid Al-Cu binary alloy, which is beneficial for preparing Al-Cu binary alloys with stable nanoscale lamellar thickness. This, in turn, facilitates the preparation of particle-reinforced Al-Cu binary alloys with excellent mechanical properties and nanoscale Al2Cu particles.

[0017] 3. Step D: The particle-reinforced Al-Cu binary alloy with micron-sized Al2Cu particles obtained in step C is subjected to semi-solid treatment. By controlling the semi-solid treatment temperature and time as well as the water quenching temperature after semi-solid treatment, an Al-Cu binary alloy with nanometer-sized eutectic (α-Al+Al2Cu) interlamellar spacing is obtained in a short time.

[0018] Fourth, the secondary extrusion in step E breaks down the eutectic structure with nanoscale interlamellar spacing into nanoscale Al2Cu particles, which are then dispersed on the α-Al matrix. The parameters of the secondary extrusion in this invention ensure that the prepared Al-Cu binary alloy has superior comprehensive mechanical properties. In step F, a large number of nanoscale precipitates are formed on the particle-reinforced Al-Cu binary alloy with nanoscale Al2Cu particles obtained in step E. The combined effect of the two types of nanoparticles significantly enhances the mechanical properties of the Al-Cu binary alloy.

[0019] In summary, this invention, based on Al-Cu binary alloys prepared by traditional casting, combines primary extrusion, semi-solid treatment, secondary extrusion, and aging processes to achieve the transformation of the non-precipitated second phase in the alloy from micron-scale lamellar to micron-scale particles, then to nano-scale lamellar, and finally to nano-scale particles. Combined with aging treatment, a particle-reinforced Al-Cu binary alloy with two types of nanoparticles is obtained, which significantly improves the comprehensive mechanical properties of Al-Cu binary alloys and greatly expands the application range of Al-Cu binary alloys.

[0020] Furthermore, in step A of the preparation method of the present invention, the mass percentage content of each constituent element in the preparation of the as-cast Al-Cu binary alloy is set as follows: 2.5-7.5% Cu, unavoidable impurity element content ≤0.1%, and the remainder is Al.

[0021] Furthermore, the specific operation of step A in the preparation method of the present invention for preparing the as-cast Al-Cu binary alloy is as follows: according to the set mass percentage ratio of each component element, pure Al is placed in a crucible and heated to 690-780℃ to melt, then Al-Cu binary intermediate alloy is added, and the mixture is heated to 720-760℃. After stirring for 2-5 minutes, the slag is removed, and the mixture is allowed to stand for 5-15 minutes. When the temperature drops to 710-740℃, the mixture is poured to obtain the as-cast Al-Cu binary alloy.

[0022] Furthermore, in the preparation method of the present invention, the annealing temperature of step B, annealing treatment, is 470-520℃, and the annealing time is 15-24h.

[0023] Furthermore, in step D of the preparation method of the present invention, the Al-Cu binary alloy obtained by hot extrusion in step C is placed in a heat treatment furnace and heated to 540-590℃ for semi-solid isothermal treatment, held for 0.1-1.5h, and then water-cooled and quenched.

[0024] Experiments have verified that the above temperature range and holding time are more conducive to the preparation of Al-Cu binary alloys with stable nanoscale interlamellar spacing, which in turn is beneficial to the preparation of particle-reinforced Al-Cu binary alloys with nanoscale Al2Cu particles that have excellent mechanical properties.

[0025] Furthermore, in step D of the preparation method of the present invention, the quenching medium for quenching treatment is water at 20-80°C.

[0026] Experiments have verified that quenching with water within the above temperature range results in a more uniform layer thickness in the semi-solid Al-Cu binary alloy, which is beneficial for preparing Al-Cu binary alloys with stable nanoscale layer thickness. This, in turn, is beneficial for preparing particle-reinforced Al-Cu binary alloys with nanoscale Al2Cu particles that have excellent mechanical properties.

[0027] Furthermore, the specific operation of the aging treatment in step F of the preparation method of the present invention is as follows: the Al-Cu binary alloy obtained in step E is aged at 110-160℃ for 8-24 hours, and then water-quenched.

[0028] Furthermore, the specific operation of the aging treatment in step F of the preparation method of the present invention is as follows: the Al-Cu binary alloy obtained in step E is aged at 110-130℃ for 8-24 hours, and then water-quenched.

[0029] Experimental results show that the Al-Cu binary alloy prepared by the above-mentioned aging treatment temperature and time has better comprehensive mechanical properties, and can be used to prepare high-performance Al alloys with excellent yield strength, tensile strength and elongation. Attached Figure Description

[0030] Figure 1 The figures show the tensile curves of two types of nanoparticle-reinforced Al-Cu binary alloys prepared in Examples 1, 2, 3, 4, and 5 of this invention.

[0031] Figure 2 SEM images of the semi-solid structures of two types of nanoparticle-reinforced Al-Cu binary alloys prepared in step D of Embodiment 1 of the present invention.

[0032] Figure 3 The image shows the HAADF-STEM image of the nanolayer eutectic prepared in step D of Embodiment 1 of the present invention under the

[011] Al zone axis.

[0033] Figure 4 The images are SEM images of the two types of nanoparticle-reinforced Al-Cu binary alloys prepared in step E of Embodiment 1 of the present invention after hot extrusion.

[0034] Figure 5 This is a bright-field TEM image of nanoscale Al2Cu particles prepared in step E of Embodiment 1 of the present invention under the

[011] Al zone axis. Detailed Implementation

[0035] Example 1

[0036] A method for preparing an Al-Cu binary alloy reinforced with two types of nanoparticles, wherein the two types of nanoparticles are eutectic fragmented nano-Al2Cu particles and precipitated nano-θ' phase, and the preparation method steps are as follows:

[0037] A. Prepare a cast Al-Cu binary alloy according to the set mass percentage of each component element; the set mass percentage of each component element is: 4.5% Cu, unavoidable impurity element content ≤0.1%, and the remainder is Al;

[0038] B. Anneal the as-cast Al-Cu binary alloy prepared in step A;

[0039] C. After the Al-Cu binary alloy obtained in step B has been annealed, it is held at 450℃ for 4 hours and then hot extruded. The extrusion temperature is 450℃, the extrusion speed is 0.2mm / s, and the extrusion ratio is 17:1.

[0040] D. Place the hot-extruded Al-Cu binary alloy obtained in step C into a heat treatment furnace, heat it to 550℃ with the furnace for semi-solid isothermal treatment, hold it for 1 hour, and then quench it with water.

[0041] E. After holding the Al-Cu binary alloy obtained in step D at 175℃ for 0.5h, it is then subjected to a second extrusion to obtain a nanoparticle-reinforced Al-Cu binary alloy; the extrusion temperature of the second extrusion is 175℃, the extrusion speed is 0.2mm / s, and the extrusion ratio is 10:1.

[0042] F. Aging treatment is performed on the nanoparticle-reinforced Al-Cu binary alloy obtained in step E to obtain two types of nanoparticle-reinforced Al-Cu binary alloys.

[0043] The specific operation for preparing the as-cast Al-Cu binary alloy in step A of this example is as follows: according to the set mass percentage ratio of each component element, pure Al is placed in a crucible and heated to 720°C to melt. Then, Al-Cu binary intermediate alloy is added, and the mixture is heated to 740°C. After stirring for 5 minutes, the slag is removed, and the mixture is allowed to stand for 10 minutes. When the temperature drops to 720°C, it is poured to obtain the as-cast Al-Cu binary alloy.

[0044] The specific operation of step B annealing in this example is as follows: the as-cast Al-Cu binary alloy is placed in a heat treatment furnace, heated to 495°C, held for 24 hours, and then cooled to room temperature in the furnace.

[0045] In this example, the quenching medium used in step D is water at 20°C.

[0046] The specific operation of the aging treatment in step F of this example is: aging the Al-Cu binary alloy obtained in step E at 110℃ for 24 hours, and then water-quenching it.

[0047] The Al-Cu binary alloy prepared in this example has a tensile strength of 472 MPa, a yield strength of 374 MPa, and an elongation of 13.7%.

[0048] Figure 2 This is a SEM image of the semi-solid structure of the Al-Cu binary alloy after semi-solid isothermal treatment in this embodiment. After semi-solid isothermal treatment, solute atoms are enriched at the grain boundaries and remelted. After rapid quenching, a eutectic structure with a continuous network structure is formed. At the same time, small liquid pools also exist within the grains due to solute atom segregation, local defects, or local stress concentration, which are formed during remelting and solidification. Figure 3 The image shows a HAADF-STEM image of the Al2Cu eutectic phase in nanolayers along the

[011] Al zone axis. The high-magnification image shows that after semi-solid isothermal treatment, the Al2Cu eutectic phase is a uniform layered structure with a thickness of less than 100 nm. Figure 4 The images show SEM images of two types of nanoparticle-reinforced Al-Cu binary alloys after hot extrusion. The nano-Al2Cu layers at the grain boundaries are completely broken into nano-Al2Cu particles and distributed in a band-like pattern along the extrusion direction. Meanwhile, the small crystal cells within the grains remain intact, exhibiting strong stiffness. Figure 5 The image shows a bright-field TEM image of nano-fragmented Al2Cu particles under the

[011] Al zone axis. The fragmented nano-Al2Cu particles are uniform in size, with particle sizes all less than 100 nm, and a large number of nano-precipitated particles still exist around the nano-fragmented particles.

[0049] Example 2

[0050] A method for preparing an Al-Cu binary alloy reinforced with two types of nanoparticles, wherein the two types of nanoparticles are eutectic fragmented nano-Al2Cu particles and precipitated nano-θ' phase, and the preparation method steps are as follows:

[0051] A. Prepare a cast Al-Cu binary alloy according to the set mass percentage of each component element; the set mass percentage of each component element is: 4.5% Cu, unavoidable impurity element content ≤0.1%, and the remainder is Al;

[0052] B. Anneal the as-cast Al-Cu binary alloy prepared in step A;

[0053] C. After the Al-Cu binary alloy obtained in step B has been annealed, it is held at 440℃ for 4 hours and then hot extruded. The extrusion temperature is 440℃, the extrusion speed is 0.3mm / s, and the extrusion ratio is 17:1.

[0054] D. Place the hot-extruded Al-Cu binary alloy obtained in step C into a heat treatment furnace, heat it to 550℃ with the furnace for semi-solid isothermal treatment, hold it for 1 hour, and then quench it with water.

[0055] E. After holding the Al-Cu binary alloy obtained in step D at 175℃ for 2 hours, it is then subjected to a second extrusion to obtain a nanoparticle-reinforced Al-Cu binary alloy; the extrusion temperature of the second extrusion is 175℃, the extrusion speed is 0.3mm / s, and the extrusion ratio is 10:1.

[0056] F. Aging treatment is performed on the nanoparticle-reinforced Al-Cu binary alloy obtained in step E to obtain two types of nanoparticle-reinforced Al-Cu binary alloys.

[0057] The specific operation for preparing the as-cast Al-Cu binary alloy in step A of this example is as follows: according to the set mass percentage ratio of each component element, pure Al is placed in a crucible and heated to 710°C to melt. Then, Al-Cu binary intermediate alloy is added, and the mixture is heated to 745°C. After stirring for 4 minutes, the slag is removed, and the mixture is allowed to stand for 15 minutes. When the temperature drops to 720°C, the mixture is poured to obtain the as-cast Al-Cu binary alloy.

[0058] The specific operation of step B annealing in this example is as follows: the as-cast Al-Cu binary alloy is placed in a heat treatment furnace, heated to 495°C, held for 24 hours, and then cooled to room temperature in the furnace.

[0059] In this example, the quenching medium used in step D is water at 35°C.

[0060] The specific operation of the aging treatment in step F of this example is: aging the Al-Cu binary alloy obtained in step E at 130℃ for 23 hours, and then water-quenching it.

[0061] The Al-Cu binary alloy prepared in this example has a tensile strength of 407 MPa, a yield strength of 281 MPa, and an elongation of 16.1%.

[0062] Example 3

[0063] A method for preparing an Al-Cu binary alloy reinforced with two types of nanoparticles, wherein the two types of nanoparticles are eutectic fragmented nano-Al2Cu particles and precipitated nano-θ' phase, and the preparation method steps are as follows:

[0064] A. Prepare a cast Al-Cu binary alloy according to the set mass percentage of each component element; the set mass percentage of each component element is: 7.1% Cu, unavoidable impurity element content ≤0.1%, and the remainder is Al;

[0065] B. Anneal the as-cast Al-Cu binary alloy prepared in step A;

[0066] C. After the Al-Cu binary alloy obtained in step B has been annealed, it is held at 435℃ for 3 hours and then hot extruded. The extrusion temperature is 435℃, the extrusion speed is 0.28mm / s, and the extrusion ratio is 9:1.

[0067] D. Place the hot-extruded Al-Cu binary alloy obtained in step C into a heat treatment furnace, heat it to 600℃ with the furnace for semi-solid isothermal treatment, hold it for 11 minutes, and then quench it with water.

[0068] E. After holding the Al-Cu binary alloy obtained in step D at 200℃ for 1.5h, it is then subjected to a second extrusion to obtain a nanoparticle-reinforced Al-Cu binary alloy; the extrusion temperature of the second extrusion is 200℃, the extrusion speed is 0.35mm / s, and the extrusion ratio is 9:1.

[0069] F. Aging treatment is performed on the nanoparticle-reinforced Al-Cu binary alloy obtained in step E to obtain two types of nanoparticle-reinforced Al-Cu binary alloys.

[0070] The specific operation for preparing the as-cast Al-Cu binary alloy in step A of this example is as follows: according to the set mass percentage ratio of each component element, pure Al is placed in a crucible and heated to 730°C to melt. Then, Al-Cu binary intermediate alloy is added, and the mixture is heated to 750°C. After stirring for 3 minutes, the slag is removed, and the mixture is allowed to stand for 11 minutes. When the temperature drops to 725°C, the mixture is poured to obtain the as-cast Al-Cu binary alloy.

[0071] The specific operation of step B annealing in this example is as follows: the as-cast Al-Cu binary alloy is placed in a heat treatment furnace, heated to 480°C, held for 23 hours, and then cooled to room temperature in the furnace.

[0072] In this example, the quenching medium used in step D is water at 40°C.

[0073] The specific operation of the aging treatment in step F of this example is: aging the Al-Cu binary alloy obtained in step E at 120℃ for 24 hours, and then water-quenching it.

[0074] The Al-Cu binary alloy prepared in this example has a tensile strength of 450 MPa, a yield strength of 339 MPa, and an elongation of 17.8%.

[0075] Example 4

[0076] A method for preparing an Al-Cu binary alloy reinforced with two types of nanoparticles, wherein the two types of nanoparticles are eutectic fragmented nano-Al2Cu particles and precipitated nano-θ' phase, and the preparation method steps are as follows:

[0077] A. Prepare a cast Al-Cu binary alloy according to the set mass percentage of each component element; the set mass percentage of each component element is: 5% Cu, unavoidable impurity element content ≤0.1%, and the remainder is Al;

[0078] B. Anneal the as-cast Al-Cu binary alloy prepared in step A;

[0079] C. After the Al-Cu binary alloy obtained in step B has been annealed, it is held at 400℃ for 4 hours and then hot extruded. The extrusion temperature is 400℃, the extrusion speed is 0.26mm / s, and the extrusion ratio is 17:1.

[0080] D. Place the hot-extruded Al-Cu binary alloy obtained in step C into a heat treatment furnace, heat it to 580℃ with the furnace for semi-solid isothermal treatment, hold it for 30 minutes, and then quench it with water.

[0081] E. After holding the Al-Cu binary alloy obtained in step D at 190℃ for 1 hour, it is then subjected to a second extrusion to obtain a nanoparticle-reinforced Al-Cu binary alloy; the extrusion temperature of the second extrusion is 190℃, the extrusion speed is 0.28 mm / s, and the extrusion ratio is 9:1.

[0082] F. Aging treatment is performed on the nanoparticle-reinforced Al-Cu binary alloy obtained in step E to obtain two types of nanoparticle-reinforced Al-Cu binary alloys.

[0083] The specific operation for preparing the as-cast Al-Cu binary alloy in step A of this example is as follows: according to the set mass percentage ratio of each component element, pure Al is placed in a crucible and heated to 730°C to melt. Then, Al-Cu binary intermediate alloy is added, and the mixture is heated to 750°C. After stirring for 3 minutes, the slag is removed, and the mixture is allowed to stand for 11 minutes. When the temperature drops to 725°C, the mixture is poured to obtain the as-cast Al-Cu binary alloy.

[0084] The specific operation of step B annealing in this example is as follows: the as-cast Al-Cu binary alloy is placed in a heat treatment furnace, heated to 475°C, held for 21 hours, and then cooled to room temperature in the furnace.

[0085] In this example, the quenching medium used in step D is water at 80°C.

[0086] The specific operation of the aging treatment in step F of this example is: aging the Al-Cu binary alloy obtained in step E at 160℃ for 10 hours, and then water-quenching it.

[0087] The Al-Cu binary alloy prepared in this example has a tensile strength of 351 MPa, a yield strength of 265 MPa, and an elongation of 12.0%.

[0088] Example 5

[0089] A method for preparing an Al-Cu binary alloy reinforced with two types of nanoparticles, wherein the two types of nanoparticles are eutectic fragmented nano-Al2Cu particles and precipitated nano-θ' phase, and the preparation method steps are as follows:

[0090] A. Prepare a cast Al-Cu binary alloy according to the set mass percentage of each component element; the set mass percentage of each component element is: 4.5% Cu, unavoidable impurity element content ≤0.1%, and the remainder is Al;

[0091] B. Anneal the as-cast Al-Cu binary alloy prepared in step A;

[0092] C. After the Al-Cu binary alloy obtained in step B has been annealed, it is held at 380℃ for 4 hours and then hot extruded. The extrusion temperature is 380℃, the extrusion speed is 2mm / s, and the extrusion ratio is 17:1.

[0093] D. Place the hot-extruded Al-Cu binary alloy obtained in step C into a heat treatment furnace, heat it to 550℃ with the furnace for semi-solid isothermal treatment, hold it for 40 minutes, and then quench it with water.

[0094] E. After holding the Al-Cu binary alloy obtained in step D at 200℃ for 0.5h, it is then subjected to a second extrusion to obtain a nanoparticle-reinforced Al-Cu binary alloy; the extrusion temperature of the second extrusion is 200℃, the extrusion speed is 2mm / s, and the extrusion ratio is 10:1.

[0095] F. Aging treatment is performed on the nanoparticle-reinforced Al-Cu binary alloy obtained in step E to obtain two types of nanoparticle-reinforced Al-Cu binary alloys.

[0096] The specific operation for preparing the as-cast Al-Cu binary alloy in step A of this example is as follows: according to the set mass percentage ratio of each component element, pure Al is placed in a crucible and heated to 730°C to melt. Then, Al-Cu binary intermediate alloy is added, and the mixture is heated to 750°C. After stirring for 3 minutes, the slag is removed, and the mixture is allowed to stand for 11 minutes. When the temperature drops to 725°C, the mixture is poured to obtain the as-cast Al-Cu binary alloy.

[0097] The specific operation of step B annealing in this example is as follows: the as-cast Al-Cu binary alloy is placed in a heat treatment furnace, heated to 475°C, held for 19 hours, and then cooled to room temperature in the furnace.

[0098] In this example, the quenching medium used in step D is water at 45°C.

[0099] The specific operation of the aging treatment in step F of this example is: aging the Al-Cu binary alloy obtained in step E at 120℃ for 24 hours, and then water-quenching it.

[0100] The Al-Cu binary alloy prepared in this example has a tensile strength of 388 MPa, a yield strength of 282 MPa, and an elongation of 16.4%.

[0101] Figure 1 Tensile curves of the two types of nanoparticle-reinforced Al-Cu binary alloys prepared in Examples 1, 2, 3, 4, and 5 above.

[0102] Example 6

[0103] A method for preparing an Al-Cu binary alloy reinforced with two types of nanoparticles, wherein the two types of nanoparticles are eutectic fragmented nano-Al2Cu particles and precipitated nano-θ' phase, and the preparation method steps are as follows:

[0104] A. Prepare a cast Al-Cu binary alloy according to the set mass percentage of each component element; the set mass percentage of each component element is: 2.5% Cu, unavoidable impurity element content ≤0.1%, and the remainder is Al;

[0105] B. Anneal the as-cast Al-Cu binary alloy prepared in step A;

[0106] C. After the Al-Cu binary alloy obtained in step B has been annealed, it is held at 300℃ for 4 hours and then hot extruded. The extrusion temperature is 300℃, the extrusion speed is 0.1mm / s, and the extrusion ratio is 30:1.

[0107] D. Place the hot-extruded Al-Cu binary alloy obtained in step C into a heat treatment furnace, heat it to 530℃ with the furnace for semi-solid isothermal treatment, hold it for 3 hours, and then quench it with water.

[0108] E. After holding the Al-Cu binary alloy obtained in step D at 150℃ for 1.8h, it is then subjected to secondary extrusion to obtain nanoparticle-reinforced Al-Cu binary alloy; the extrusion temperature of the secondary extrusion is 150℃, the extrusion speed is 0.1mm / s, and the extrusion ratio is 30:1.

[0109] F. Aging treatment is performed on the nanoparticle-reinforced Al-Cu binary alloy obtained in step E to obtain two types of nanoparticle-reinforced Al-Cu binary alloys.

[0110] The specific operation for preparing the as-cast Al-Cu binary alloy in step A of this example is as follows: According to the set mass percentage ratio of each component element, pure Al is placed in a crucible and heated to 690°C to melt. Then, Al-Cu binary intermediate alloy is added, and the mixture is heated to 720°C. After stirring for 5 minutes, the slag is removed, and the mixture is allowed to stand for 15 minutes. When the temperature drops to 710°C, the mixture is poured to obtain the as-cast Al-Cu binary alloy.

[0111] The specific operation of step B annealing in this example is as follows: the as-cast Al-Cu binary alloy is placed in a heat treatment furnace, heated to 520°C, held for 15 hours, and then cooled to room temperature in the furnace.

[0112] In this example, the quenching medium used in step D is water at 45°C.

[0113] The specific operation of the aging treatment in step F of this example is: aging the Al-Cu binary alloy obtained in step E at 120℃ for 24 hours, and then water-quenching it.

[0114] Example 7

[0115] A method for preparing an Al-Cu binary alloy reinforced with two types of nanoparticles, wherein the two types of nanoparticles are eutectic fragmented nano-Al2Cu particles and precipitated nano-θ' phase, and the preparation method steps are as follows:

[0116] A. Prepare a cast Al-Cu binary alloy according to the set mass percentage of each component element; the set mass percentage of each component element is: 7.5% Cu, unavoidable impurity element content ≤0.1%, and the remainder is Al;

[0117] B. Anneal the as-cast Al-Cu binary alloy prepared in step A;

[0118] C. After the Al-Cu binary alloy obtained in step B has been annealed, it is held at 450℃ for 2 hours and then hot extruded. The extrusion temperature is 450℃, the extrusion speed is 5mm / s, and the extrusion ratio is 15:1.

[0119] D. Place the hot-extruded Al-Cu binary alloy obtained in step C into a heat treatment furnace, heat it to 630℃ with the furnace for semi-solid isothermal treatment, hold it for 0.1h, and then water-quench it.

[0120] E. After holding the Al-Cu binary alloy obtained in step D at 250℃ for 0.5h, it is then subjected to secondary extrusion to obtain nanoparticle-reinforced Al-Cu binary alloy; the extrusion temperature of the secondary extrusion is 250℃, the extrusion speed is 5mm / s, and the extrusion ratio is 15:1.

[0121] F. Aging treatment is performed on the nanoparticle-reinforced Al-Cu binary alloy obtained in step E to obtain two types of nanoparticle-reinforced Al-Cu binary alloys.

[0122] The specific operation for preparing the as-cast Al-Cu binary alloy in step A of this example is as follows: according to the set mass percentage ratio of each component element, pure Al is placed in a crucible and heated to 780°C to melt. Then, Al-Cu binary intermediate alloy is added, and the mixture is heated to 760°C. After stirring for 2 minutes, the slag is removed, and the mixture is allowed to stand for 5 minutes. When the temperature drops to 740°C, the mixture is poured to obtain the as-cast Al-Cu binary alloy.

[0123] The specific operation of step B annealing in this example is as follows: the as-cast Al-Cu binary alloy is placed in a heat treatment furnace, heated to 470°C, held for 19 hours, and then cooled to room temperature in the furnace.

[0124] In this example, the quenching medium used in step D is water at 45°C.

[0125] The specific operation of the aging treatment in step F of this example is as follows: the Al-Cu binary alloy obtained in step E is aged at 160℃ for 8 hours, and then water-quenched.

[0126] Example 8

[0127] A method for preparing an Al-Cu binary alloy reinforced with two types of nanoparticles, wherein the two types of nanoparticles are eutectic fragmented nano-Al2Cu particles and precipitated nano-θ' phase, and the preparation method steps are as follows:

[0128] A. Prepare a cast Al-Cu binary alloy according to the set mass percentage of each component element; the set mass percentage of each component element is: 2% Cu, unavoidable impurity element content ≤0.1%, and the remainder is Al;

[0129] B. Anneal the as-cast Al-Cu binary alloy prepared in step A;

[0130] C. After the Al-Cu binary alloy obtained in step B has been annealed, it is held at 380℃ for 4 hours and then hot extruded. The extrusion temperature is 380℃, the extrusion speed is 2mm / s, and the extrusion ratio is 17:1.

[0131] D. Place the hot-extruded Al-Cu binary alloy obtained in step C into a heat treatment furnace, heat it to 540℃ with the furnace for semi-solid isothermal treatment, hold it for 1.5h, and then water-quench it.

[0132] E. After holding the Al-Cu binary alloy obtained in step D at 200℃ for 0.5h, it is then subjected to a second extrusion to obtain a nanoparticle-reinforced Al-Cu binary alloy; the extrusion temperature of the second extrusion is 200℃, the extrusion speed is 2mm / s, and the extrusion ratio is 10:1.

[0133] F. Aging treatment is performed on the nanoparticle-reinforced Al-Cu binary alloy obtained in step E to obtain two types of nanoparticle-reinforced Al-Cu binary alloys.

[0134] The specific operation for preparing the as-cast Al-Cu binary alloy in step A of this example is as follows: according to the set mass percentage ratio of each component element, pure Al is placed in a crucible and heated to 730°C to melt. Then, Al-Cu binary intermediate alloy is added, and the mixture is heated to 750°C. After stirring for 3 minutes, the slag is removed, and the mixture is allowed to stand for 11 minutes. When the temperature drops to 725°C, the mixture is poured to obtain the as-cast Al-Cu binary alloy.

[0135] The specific operation of step B annealing in this example is as follows: the as-cast Al-Cu binary alloy is placed in a heat treatment furnace, heated to 475°C, held for 19 hours, and then cooled to room temperature in the furnace.

[0136] In this example, the quenching medium used in step D is water at 45°C.

[0137] The specific operation of the aging treatment in step F of this example is: aging the Al-Cu binary alloy obtained in step E at 120℃ for 16 hours, and then water-quenching it.

[0138] Example 9

[0139] A method for preparing an Al-Cu binary alloy reinforced with two types of nanoparticles, wherein the two types of nanoparticles are eutectic fragmented nano-Al2Cu particles and precipitated nano-θ' phase, and the preparation method steps are as follows:

[0140] A. Prepare a cast Al-Cu binary alloy according to the set mass percentage of each component element; the set mass percentage of each component element is: 10% Cu, unavoidable impurity element content ≤0.1%, and the remainder is Al;

[0141] B. Anneal the as-cast Al-Cu binary alloy prepared in step A;

[0142] C. After the Al-Cu binary alloy obtained in step B has been annealed, it is held at 380℃ for 4 hours and then hot extruded. The extrusion temperature is 380℃, the extrusion speed is 2mm / s, and the extrusion ratio is 17:1.

[0143] D. Place the hot-extruded Al-Cu binary alloy obtained in step C into a heat treatment furnace, heat it to 590℃ with the furnace for semi-solid isothermal treatment, hold it for 1 hour, and then quench it with water.

[0144] E. After holding the Al-Cu binary alloy obtained in step D at 200℃ for 0.5h, it is then subjected to a second extrusion to obtain a nanoparticle-reinforced Al-Cu binary alloy; the extrusion temperature of the second extrusion is 200℃, the extrusion speed is 2mm / s, and the extrusion ratio is 10:1.

[0145] F. Aging treatment is performed on the nanoparticle-reinforced Al-Cu binary alloy obtained in step E to obtain two types of nanoparticle-reinforced Al-Cu binary alloys.

[0146] The specific operation for preparing the as-cast Al-Cu binary alloy in step A of this example is as follows: according to the set mass percentage ratio of each component element, pure Al is placed in a crucible and heated to 730°C to melt. Then, Al-Cu binary intermediate alloy is added, and the mixture is heated to 750°C. After stirring for 3 minutes, the slag is removed, and the mixture is allowed to stand for 11 minutes. When the temperature drops to 725°C, the mixture is poured to obtain the as-cast Al-Cu binary alloy.

[0147] The specific operation of step B annealing in this example is as follows: the as-cast Al-Cu binary alloy is placed in a heat treatment furnace, heated to 475°C, held for 19 hours, and then cooled to room temperature in the furnace.

[0148] In this example, the quenching medium used in step D is water at 45°C.

[0149] The specific operation of the aging treatment in step F of this example is: aging the Al-Cu binary alloy obtained in step E at 120℃ for 15 hours, and then water-quenching it.

Claims

1. A method for preparing Al-Cu binary alloys reinforced with two types of nanoparticles, comprising the following steps: A. Prepare a cast Al-Cu binary alloy according to the set mass percentage of each component element; the set mass percentage of each component element is: 2-10% Cu, unavoidable impurity element content ≤0.1%, and the remainder is Al; B. Anneal the as-cast Al-Cu binary alloy prepared in step A; C. After holding the annealed Al-Cu binary alloy obtained in step B at 300-450℃ for 2-4 hours, hot extrusion is carried out. The extrusion temperature is 300-450℃, the extrusion speed is 0.1-5mm / s, and the extrusion ratio is 9-30:

1. D. Place the hot-extruded Al-Cu binary alloy obtained in step C into a heat treatment furnace and heat it to 530-630℃ for semi-solid isothermal treatment. Hold it for 0.1-3 hours to transform the micron-sized Al2Cu particles into a eutectic α-Al+Al2Cu structure with a lamellar spacing of nanometers. Then, water-cool and quench it. E. After holding the Al-Cu binary alloy obtained in step D at 150-250℃ for 0.5-2h, it is then subjected to secondary extrusion to break the eutectic structure with nanoscale interlamellar spacing into nanoscale Al2Cu particles and disperse them on the α-Al matrix, thereby obtaining a nanoparticle-reinforced Al-Cu binary alloy; the extrusion temperature of the secondary extrusion is 150-250℃, the extrusion speed is 0.1-5mm / s, and the extrusion ratio is 9-30:1; F. The nanoparticle-reinforced Al-Cu binary alloy obtained in step E is subjected to aging treatment. Specifically, the nanoparticle-reinforced Al-Cu binary alloy obtained in step E is aged at 110-160℃ for 8-24 hours, and then water-cooled and quenched to allow a large amount of θ' phase to precipitate, thereby obtaining two types of nanoparticle-reinforced Al-Cu binary alloys.

2. The method for preparing two types of nanoparticle reinforced Al-Cu binary alloys according to claim 1, characterized in that: The mass percentage of each component element in step A for preparing the as-cast Al-Cu binary alloy is set as follows: 2.5-7.5% Cu, unavoidable impurity element content ≤0.1%, and the remainder being Al.

3. The method for preparing two types of nanoparticle reinforced Al-Cu binary alloys according to claim 1, characterized in that: The specific operation for preparing the as-cast Al-Cu binary alloy in step A is as follows: according to the set mass percentage ratio of each component element, pure Al is placed in a crucible and heated to 690-780℃ to melt. Then, Al-Cu binary intermediate alloy is added, and the mixture is heated to 720-760℃. After stirring for 2-5 minutes, the slag is removed, and the mixture is allowed to stand for 5-15 minutes. When the temperature drops to 710-740℃, the mixture is poured to obtain the Al-Cu binary alloy ingot.

4. The method for preparing a two-type nanoparticle-reinforced Al-Cu binary alloy according to claim 1, characterized in that: The annealing temperature for step B is 470-520℃, and the annealing time is 15-24h.

5. The method for preparing a two-type nanoparticle-reinforced Al-Cu binary alloy according to claim 1, characterized in that: In step D, the Al-Cu binary alloy obtained from hot extrusion in step C is placed in a heat treatment furnace and heated to 540-590℃ for semi-solid isothermal treatment, held for 0.1-1.5h, and then water-cooled and quenched.

6. The method for preparing a two-type nanoparticle-reinforced Al-Cu binary alloy according to claim 1, characterized in that: The quenching medium used in step D is water at 20-80℃.

7. The method for preparing a two-type nanoparticle-reinforced Al-Cu binary alloy according to claim 1, characterized in that: The specific operation of the aging treatment in step F is as follows: the Al-Cu binary alloy obtained in step E is aged at 110-130℃ for 8-24 hours, and then water-quenched.

8. A binary Al-Cu alloy reinforced with two types of nanoparticles, characterized in that: The two types of nanoparticle-reinforced Al-Cu binary alloys are prepared by any one of the preparation methods in claims 1-7, and the two types of nanoparticles are eutectic broken nano-Al2Cu particles and precipitated nano-θ' phases, respectively.

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