An in-situ particulate reinforced aluminum-copper alloy and a method of making the same

Abstract

This invention belongs to the field of aluminum-copper alloy casting technology, and particularly relates to an in-situ particle-reinforced aluminum-copper alloy and its preparation method. The aluminum-copper alloy comprises the following components by weight percentage: 6.0% < Cu < 7.5%, 0.3% < Mn < 0.5%, 0.2% < Cd < 0.5%, 0.1% < Zr < 0.3%, 0.05% < Ti < 0.5%, 0 < V < 0.2%, 0.005 < B < 0.5%, 0 < Ce < 0.5%, with the balance being Al. This invention enhances the strength and plasticity of the alloy by adding a powder mixture of K2TiF6, KBF4, and CeO2 to form dispersed in-situ TiB2 particles; simultaneously, the addition of Ce disperses the TiB2 particles and other precipitated phases in the matrix, resulting in significant grain refinement and narrowing of the dendrite spacing.

Description

Technical Field

[0001] This invention belongs to the field of aluminum-copper alloy casting technology, and particularly relates to an in-situ particle-reinforced aluminum-copper alloy and its preparation method. Background Technology

[0002] Aluminum-copper alloys possess excellent room-temperature and high-temperature mechanical properties, as well as machinability, and are widely used in automotive components, particularly engine block parts. To further improve the mechanical properties of these alloys, the industry has begun introducing TiB2 as a reinforcing particle into the aluminum alloy matrix. The introduction of TiB2 reinforcing particles effectively enhances the mechanical properties of the alloy at both room and high temperatures, and also improves its creep resistance, thereby meeting the performance requirements of engines during operation.

[0003] However, when reinforcing particles are added to the melt, they will cluster, which will affect the viscosity of the alloy melt and reduce the fluidity of the alloy to a certain extent. At the same time, after cooling, the reinforcing particle clusters will gather at the grain boundaries, causing stress concentration during deformation and reducing the elongation of the alloy.

[0004] Chinese Patent CN110129641B discloses a high-performance in-situ TiB2 particle-reinforced aluminum matrix composite material and its preparation method. The main alloying element Cu content is 4.5%-5.3%, and it also contains elements such as Mn, Ti, Cd, Zr, V, and Y. The preparation method involves mixing potassium fluoroborate (KBF4) and potassium fluorotitanate (K2TiF6), pressing them with alcohol to form preforms, drying them in an electric heating drying oven, and then reserving them for later use. The TiB2 reinforcing particles in the preforms are melted into the molten metal in a layer-by-layer peeling manner to react. After the reaction, the molten metal and molten salt are separated by extracting the molten metal. The separated molten metal is then refined and cast to obtain a composite material with uniformly distributed and finely sized reinforcing particles, which improves the tensile strength of the composite material. However, this material has a high content of alloying elements, requiring a variety of intermediate alloys. In addition, the mixed salt needs to be pre-pressed with alcohol into preforms, which increases the difficulty of operation on the smelting site. Furthermore, the high alloy content will increase the viscosity of the alloy melt, thereby reducing the alloy's forming ability.

[0005] The aforementioned patents describe a method for preparing reinforced aluminum-copper alloys with improved mechanical properties, but this requires specific pretreatment processes. Furthermore, the presence of Zr may lead to the formation of (Ti,Zr)B2 compounds after the addition of TiB2 reinforcing particles, thus reducing the refining and strengthening effect of the TiB2 particles and hindering performance improvement. Additionally, while reinforcing particles are widely used in aluminum alloys, their application in cast aluminum-copper alloys has been less explored. Therefore, this patent provides a simple method for preparing an in-situ TiB2 particle-based cast aluminum-copper alloy that improves mechanical properties. Summary of the Invention

[0006] In view of this, the present invention proposes an in-situ particle-reinforced aluminum-copper alloy and its preparation method to solve the problem that TiB2 reinforcing particles in existing aluminum-copper alloys are prone to agglomeration in the melt, thereby reducing the alloy performance.

[0007] The technical solution of the present invention is implemented as follows: On one hand, the present invention provides an in-situ particle-reinforced aluminum-copper alloy, which, by weight percentage, comprises the following components: 6.0% < Cu < 7.5%, 0.3% < Mn < 0.5%, 0.2% < Cd < 0.5%, 0.1% < Zr < 0.3%, 0.05% < Ti < 0.5%, 0 < V < 0.2%, 0.005 < B < 0.5%, 0 < Ce < 0.5%, with the balance being Al.

[0008] In this invention, Cu is the main strengthening element in aluminum-copper alloys, primarily improving the alloy's strength and hardness by forming the Al₂Cu phase. A Cu content of 6.0 wt.%-7.5 wt.% achieves a good strength-ductility balance. If the Cu content is ≤6.0 wt.%, the alloy strength may be insufficient; ≥7.5 wt.% may lead to excessive Al₂Cu phase formation, making the alloy brittle.

[0009] Mn is mainly used to improve the corrosion resistance and high-temperature strength of alloys, while also refining the grain size. When the Mn content is 0.3wt.%-0.5wt.%, Mn can form a dispersed Al6Mn phase, effectively improving the alloy's properties. An Mn content ≤0.3wt.% may not achieve the desired strengthening effect; ≥0.5wt.% may lead to the formation of excessive coarse Mn compounds, which could actually reduce the alloy's plasticity.

[0010] Cd can improve the creep resistance and high-temperature strength of alloys. When the Cd content is 0.2wt.%-0.5wt.%, it can be uniformly distributed on the grain boundaries, effectively hindering dislocation movement. A Cd content ≤0.2wt.% may not achieve the expected creep resistance effect; ≥0.5wt.% may lead to cadmium toxicity issues, and excessive Cd may also reduce the ductility of the alloy.

[0011] Zr is mainly used to refine grains and increase the recrystallization temperature of alloys. When the Zr content is 0.1wt.%-0.3wt.%, fine Al3Zr phases can be formed, effectively pinning grain boundaries. A Zr content ≤0.1wt.% may not achieve the desired grain refining effect; ≥0.3wt.% may lead to excessive Zr reacting with Ti and B, affecting the formation of TiB2 particles.

[0012] Ti is mainly used to form in-situ TiB2 particles and refine grains. When the Ti content is 0.05wt.%-0.5wt.%, Ti can react with B to form uniformly distributed TiB2 particles. Ti content ≤0.05wt.% may not be able to form enough TiB2 particles; ≥0.5wt.% may lead to the formation of too many coarse TiB2 particles, affecting the plasticity of the alloy.

[0013] V can improve the high-temperature strength and creep resistance of alloys. A V content of 0 wt.%–0.2 wt.% can form a fine, dispersed phase; more preferably, a V content of 0.05 wt.%–0.2 wt.% is preferred. A V content ≥ 0.2 wt.% may lead to the formation of excessive V compounds, affecting the alloy's plasticity.

[0014] Boron (B) is mainly used to react with Ti to form TiB2 particles. When the B content is 0.005 wt.% to 0.5 wt.%, it can react sufficiently with Ti. A B content ≤ 0.005 wt.% may not be able to form enough TiB2 particles; ≥ 0.5 wt.% may result in excessive free boron, affecting the electrical conductivity of the alloy.

[0015] Ce can refine grains and improve the high-temperature properties of alloys. When the Ce content is 0 wt.%-0.5 wt.%, it can effectively improve the morphology of the second phase. More preferably, the Ce content is 0.2 wt.%-0.5 wt.%. A Ce content ≥0.5 wt.% may lead to the formation of excessive Ce compounds, affecting the plasticity and processing properties of the alloy.

[0016] On the other hand, the present invention provides a method for preparing in-situ particle-reinforced aluminum-copper alloy, comprising the following steps:

[0017] S1. According to the alloy composition ratio, the raw materials corresponding to Cu, Mn, Zr, V, Al and Cd are mixed and preheated to form the first raw material;

[0018] S2. Heat the first raw material to melt it into a melt, let it stand and cool to 740-760℃, and then refine the melt.

[0019] S3. Mix the raw materials corresponding to Ti, B and Ce and preheat them to form the second raw material; heat the refined melt in step S2, add the second raw material to the melt and stir, then let it stand and cool to 740-760℃, and cast it to obtain the aluminum-copper alloy.

[0020] Specifically, preheating the raw materials in steps S1 and S2 reduces energy consumption and oxidation loss during melting; subsequent melting and refining processes ensure the uniformity and purity of the alloy composition. In step S3, adding a mixture of K2TiF6, KBF4, and CeO2 to the aluminum-copper alloy melt disperses the in-situ generated TiB2 particles, reduces TiB2 aggregation at grain boundaries, thereby refining the primary grains and effectively reducing the secondary dendrite spacing of the alloy. Casting at 740-760℃ ensures the alloy's fluidity while avoiding microstructure coarsening that may result from excessively high temperatures. This step-by-step feeding and temperature control method not only simplifies the operation but also effectively solves the problem of TiB2 particle clustering in traditional methods, while simultaneously optimizing the microstructure through the effect of Ce. Therefore, this method can prepare high-performance aluminum-copper alloys with uniformly distributed TiB2 particles, optimized second-phase morphology, and refined grain structure, significantly improving the alloy's overall mechanical properties.

[0021] Based on the above technical solution, preferably, in step S1, Cu, Mn, Zr, and V are added in the form of Al-Cu alloy, Al-Mn alloy, Al-Zr alloy, and Al-V alloy, respectively. The Al-Cu alloy has a Cu content of 50 wt.%, the Al-Mn alloy has a Mn content of 10 wt.%, the Al-Zr alloy has a Zr content of 10 wt.%, and the Al-V alloy has a V content of 10 wt.%. Al and Cd are added in the form of pure metals.

[0022] Based on the above technical solutions, preferably, in step S1, the preheating temperature is 100-140℃ and the preheating time is 1-2h.

[0023] Based on the above technical solutions, preferably, in step S2, refining specifically includes: adding 0.5-1.5% of hexachloroethane by mass of the total alloy to the melt for refining, and then performing slag removal treatment.

[0024] Adding hexachloroethane can purify the melt and remove bubbles. Hexachloroethane decomposes in the high-temperature melt, releasing chlorine gas. This process has multiple functions: First, the chlorine gas reacts with impurities in the melt (such as hydrogen, sodium, calcium, etc.) to form easily removable chlorides. These chlorides float to the surface of the melt and can be removed by skimming. Second, the chlorine gas bubbles can adsorb hydrogen gas in the melt as they rise, effectively reducing the porosity of the casting. Third, the stirring effect of chlorine gas promotes the homogeneity of the melt.

[0025] Based on the above technical solution, preferably, in step S3, Ti, B, and Ce are premixed and added to the melt in the form of K2TiF6 powder, KBF4 powder, and CeO2 powder, respectively. After premixing the K2TiF6 powder, KBF4 powder, and CeO2 powder at room temperature, preheating is performed at a temperature of 100-140℃ for 1-2 hours to remove moisture from the raw material powders.

[0026] Based on the above technical solutions, preferably, the particle size of the K2TiF6 powder, KBF4 powder, and CeO2 powder is 0.5-1.5μm.

[0027] Based on the above technical solutions, preferably, the Ti content in the K2TiF6 powder is 0.4-0.6 wt.%, the B content in the KBF4 powder is 0.8-1.2 wt.%, and the Ce content in the CeO2 powder is 0.4-0.6 wt.%.

[0028] Based on the above technical solution, preferably, in step S3, the refined melt is heated to 820-880℃, the second raw material is added to the melt, and the temperature is maintained at 820-880℃ for 40-80 minutes before stirring.

[0029] Based on the above technical solutions, preferably, in step S3, the aluminum-copper alloy includes: dispersed in-situ TiB2 particles, and Al2Cu and Al6Mn second phases distributed in a discontinuous skeleton shape.

[0030] In this invention, a mixture of K2TiF6, KBF4, and CeO2 powders is added to form dispersed in-situ TiB2 particles and discontinuously distributed Al2Cu and Al6Mn second phases. The dispersed TiB2 particles act as heterogeneous nucleation sites, promoting grain refinement, increasing grain boundary area, and strengthening the ability of grain boundaries to impede dislocation movement, thereby improving the alloy's strength and plasticity. Simultaneously, these particles effectively pin grain boundaries, inhibiting grain growth and improving the alloy's high-temperature stability. The discontinuously distributed Al2Cu and Al6Mn second phases reduce the cutting effect on the matrix, decrease stress concentration, and improve the alloy's toughness and fatigue resistance. The formation principle of this microstructure is as follows: the addition of a powder mixture of K2TiF6, KBF4, and CeO2 forms dispersed in-situ TiB2 particles in the alloy. The addition of CeO2 powder causes the TiB2 particles to be dispersed in the matrix, thereby resulting in significant grain refinement of the alloy and narrowing of the dendrite spacing. At the same time, the addition of Ce also causes the Al2Cu and Al6Mn second phase morphology at the grain boundaries to change from a continuous network to a discontinuous skeleton.

[0031] The in-situ particle-reinforced aluminum-copper alloy and its preparation method of the present invention have the following advantages over the prior art:

[0032] (1) By adding a powder mixture of K2TiF6, KBF4 and CeO2, dispersed in-situ TiB2 particles are formed in the alloy. The dispersed TiB2 particles serve as heterogeneous nucleation cores, which promote grain refinement, increase grain boundary area, and enhance the ability of grain boundaries to hinder dislocation movement, thereby improving the strength and plasticity of the alloy.

[0033] (2) By adding 0.5wt.% CeO2 powder, TiB2 particles are dispersed in the matrix, thereby making the alloy produce obvious grain refinement and narrowing the dendrite spacing; at the same time, the addition of Ce element will also change the morphology of Al2Cu and Al6Mn second phase at the grain boundary from continuous network to discontinuous skeleton, reducing the cutting effect of the second phase on the matrix. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 This is a flowchart of the preparation method of the in-situ particle-reinforced aluminum-copper alloy of the present invention;

[0036] Figure 2 The metallographic structures of the aluminum-copper alloys prepared in Example 1 and Comparative Examples 1-3 of this invention are shown in the diagram.

[0037] Figure 3 The images show the scanning electron microscope (SEM) microstructures of the aluminum-copper alloys prepared in Example 1 and Comparative Examples 1-3 of this invention. Detailed Implementation

[0038] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0039] Example 1

[0040] This embodiment provides an in-situ particle-reinforced aluminum-copper alloy and its preparation method. The aluminum-copper alloy has the following composition by weight percentage: Cu: 7.0%; Mn: 0.4%; Cd: 0.35%; Zr: 0.2%; Ti: 0.25%; V: 0.1%; B: 0.05%; Ce: 0.25%, with the balance being Al.

[0041] The specific preparation method of the aluminum-copper alloy includes:

[0042] S1. According to the alloy composition ratio, Cu, Mn, Zr, and V elements in the alloy are added in the form of Al-Cu (Cu content 50 wt.%), Al-Mn (Mn content 10 wt.%), Al-Zr (Zr content 10 wt.%), and Al-V (V content 10 wt.%) master alloys, respectively. Al and Cd are added in the form of pure metals. After the raw materials are prepared, they are preheated at 120℃ for 1.5 hours to form the first raw material.

[0043] S2. The first raw material is heated and melted to form a melt, which is then allowed to cool to 750°C. 1.0% of the total mass of the alloy is added to the melt to refine it, and slag is removed by skimming with a slag skimmer.

[0044] S3. A pre-weighed mixture of K2TiF6 powder (Ti content 0.5 wt.%), KBF4 powder (B content 1 wt.%), and CeO2 powder (Ce content 0.5 wt.%) is mixed evenly at room temperature and preheated by wrapping with aluminum foil. The particle size of K2TiF6 powder, KBF4 powder, and CeO2 powder is 1.0 μm. The preheating temperature is 120°C and the preheating time is 1.5 h to form the second raw material. The refined melt from step S2 is heated to 850°C, and the second raw material is pressed into the melt by a bell jar. The melt is held at 850°C for 60 min and then stirred. The melt is then allowed to cool to 750°C, the oxide scale is removed, and the melt is poured into a mold preheated to 200°C to obtain the aluminum-copper alloy.

[0045] Example 2

[0046] This embodiment provides an in-situ particle-reinforced aluminum-copper alloy and its preparation method. The aluminum-copper alloy has the following composition by weight percentage: Cu: 6.05%; Mn: 0.35%; Cd: 0.25%; Zr: 0.15%; Ti: 0.1%; V: 0.05%; B: 0.1%; Ce: 0.05%, with the balance being Al.

[0047] The specific preparation method of the aluminum-copper alloy includes:

[0048] S1. According to the alloy composition ratio, Cu, Mn, Zr, and V elements in the alloy are added in the form of Al-Cu (Cu content 45 wt.%), Al-Mn (Mn content 8 wt.%), Al-Zr (Zr content 8 wt.%), and Al-V (V content 8 wt.%) master alloys, respectively. Al and Cd are added in the form of pure metals. After the raw materials are prepared, they are preheated at 100℃ for 1 hour to form the first raw material.

[0049] S2. The first raw material is heated and melted to form a melt, which is then allowed to cool to 740°C. 0.5% of the total mass of the alloy is added to the melt to refine it, and the slag is removed by skimming with a slag skimmer.

[0050] S3. A pre-weighed mixture of K2TiF6 powder (Ti content 0.4 wt.%), KBF4 powder (B content 0.8 wt.%), and CeO2 powder (Ce content 0.4 wt.%) is mixed evenly at room temperature and preheated by wrapping with aluminum foil. The particle size of K2TiF6 powder, KBF4 powder, and CeO2 powder is 0.5 μm. The preheating temperature is 100℃ and the preheating time is 1 h, forming the second raw material. The refined melt from step S2 is heated to 820℃, and the second raw material is pressed into the melt by a bell jar. The melt is held at 820℃ for 40 min and then stirred. The melt is then allowed to cool to 740℃, the oxide scale is removed, and the melt is poured into a mold preheated to 200℃ to obtain the aluminum-copper alloy.

[0051] Example 3

[0052] This embodiment provides an in-situ particle-reinforced aluminum-copper alloy and its preparation method. The aluminum-copper alloy has the following composition by weight percentage: Cu: 7.45%; Mn: 0.45%; Cd: 0.45%; Zr: 0.25%; Ti: 0.4%; V: 0.15%; B: 0.48%; Ce: 0.4%, with the balance being Al.

[0053] The specific preparation method of the aluminum-copper alloy includes:

[0054] S1. According to the alloy composition ratio, Cu, Mn, Zr, and V elements in the alloy are added in the form of Al-Cu (Cu content 55 wt.%), Al-Mn (Mn content 12 wt.%), Al-Zr (Zr content 12 wt.%), and Al-V (V content 12 wt.%) master alloys, respectively. Al and Cd are added in the form of pure metals. After the raw materials are prepared, they are preheated at 140℃ for 2 hours to form the first raw material.

[0055] S2. The first raw material is heated and melted to form a melt, which is then allowed to cool to 760°C. 1.5% of the total mass of the alloy is added to the melt to refine it, and the slag is removed by skimming with a slag skimmer.

[0056] S3. A pre-weighed mixture of K2TiF6 powder (Ti content 0.6 wt.%), KBF4 powder (B content 1.2 wt.%), and CeO2 powder (Ce content 0.6 wt.%) is mixed evenly at room temperature and preheated by wrapping with aluminum foil. The particle size of K2TiF6 powder, KBF4 powder, and CeO2 powder is 1.5 μm. The preheating temperature is 140°C and the preheating time is 2 h to form the second raw material. The refined melt from step S2 is heated to 880°C, and the second raw material is pressed into the melt by a bell jar. The melt is held at 880°C for 80 min and then stirred. The melt is then allowed to cool to 760°C, the oxide scale is removed, and the melt is poured into a mold preheated to 200°C to obtain the aluminum-copper alloy.

[0057] Example 4

[0058] This embodiment provides an in-situ particle-reinforced aluminum-copper alloy and its preparation method. The aluminum-copper alloy has the following composition by weight percentage: Cu: 6.5%; Mn: 0.45%; Cd: 0.4%; Zr: 0.28%; Ti: 0.15%; V: 0.15%; B: 0.3%; Ce: 0.15%, with the balance being Al.

[0059] The specific preparation method of the aluminum-copper alloy includes:

[0060] S1. According to the alloy composition ratio, Cu, Mn, Zr, and V elements in the alloy are added in the form of Al-Cu (Cu content 48 wt.%), Al-Mn (Mn content 11 wt.%), Al-Zr (Zr content 9 wt.%), and Al-V (V content 11 wt.%) master alloys, respectively. Al and Cd are added in the form of pure metals. After the raw materials are prepared, they are preheated at 140℃ for 1 hour to form the first raw material.

[0061] S2. The first raw material is heated and melted to form a melt, which is then allowed to cool to 740°C. 1.2% of the total mass of the alloy is added to the melt to refine it, and the slag is removed by a slag skimmer.

[0062] S3. A pre-weighed mixture of K2TiF6 powder (Ti content 0.5 wt.%), KBF4 powder (B content 1.1 wt.%), and CeO2 powder (Ce content 0.5 wt.%) is mixed evenly at room temperature and preheated by wrapping with aluminum foil. The particle size of K2TiF6 powder, KBF4 powder, and CeO2 powder is 1.2 μm. The preheating temperature is 140°C and the preheating time is 1 h to form the second raw material. The refined melt from step S2 is heated to 840°C. The second raw material is pressed into the melt by a bell jar. The melt is held at 840°C for 80 min and then stirred. The melt is then allowed to cool to 760°C, the oxide scale is removed, and the melt is poured into a mold preheated to 200°C to obtain the aluminum-copper alloy.

[0063] Comparative Example 1

[0064] This embodiment provides an in-situ particle-reinforced aluminum-copper alloy and its preparation method. The aluminum-copper alloy has the following composition by weight percentage: Cu: 7.0%; Mn: 0.4%; Cd: 0.35%; Zr: 0.2%; V: 0.1%; Ce: 0.25%, with the balance being Al.

[0065] The specific preparation method of the aluminum-copper alloy includes:

[0066] S1. According to the alloy composition ratio, Cu, Mn, Zr, and V elements in the alloy are added in the form of Al-Cu (Cu content 50 wt.%), Al-Mn (Mn content 10 wt.%), Al-Zr (Zr content 10 wt.%), and Al-V (V content 10 wt.%) master alloys, respectively. Al and Cd are added in the form of pure metals. After the raw materials are prepared, they are preheated at 120℃ for 1.5 hours to form the first raw material.

[0067] S2. The first raw material is heated and melted to form a melt, which is then allowed to cool to 750°C. 1.0% of the total mass of the alloy is added to the melt to refine it, and slag is removed by skimming with a slag skimmer.

[0068] S3. CeO2 powder (Ce content of 0.5 wt.%) is mixed evenly at room temperature and preheated by wrapping with aluminum foil. The particle size of CeO2 powder is 1.0 μm, the preheating temperature is 120℃, and the preheating time is 1.5 h to form the second raw material. The refined melt from step S2 is heated to 850℃, and the second raw material is pressed into the melt by a bell jar. The melt is held at 850℃ for 60 min and then stirred. The melt is then allowed to cool to 750℃, the oxide scale is removed, and the melt is poured into a mold preheated to 200℃ to obtain the aluminum-copper alloy.

[0069] Comparative Example 2

[0070] This embodiment provides an in-situ particle-reinforced aluminum-copper alloy and its preparation method. The aluminum-copper alloy has the following composition by weight percentage: Cu: 7.0%; Mn: 0.4%; Cd: 0.35%; Zr: 0.2%; Ti: 0.25%; V: 0.1%; B: 0.05%, with the balance being Al.

[0071] The specific preparation method of the aluminum-copper alloy includes:

[0072] S1. According to the alloy composition ratio, Cu, Mn, Zr, and V elements in the alloy are added in the form of Al-Cu (Cu content 50 wt.%), Al-Mn (Mn content 10 wt.%), Al-Zr (Zr content 10 wt.%), and Al-V (V content 10 wt.%) master alloys, respectively. Al and Cd are added in the form of pure metals. After the raw materials are prepared, they are preheated at 120℃ for 1.5 hours to form the first raw material.

[0073] S2. The first raw material is heated and melted to form a melt, which is then allowed to cool to 750°C. 1.0% of the total mass of the alloy is added to the melt to refine it, and slag is removed by skimming with a slag skimmer.

[0074] S3. A pre-mixed mixture of K2TiF6 powder (Ti content 0.5 wt.%) and KBF4 powder (B content 1 wt.%) is mixed evenly at room temperature and preheated by wrapping with aluminum foil. The particle size of K2TiF6 powder and KBF4 powder is 1.0 μm. The preheating temperature is 120℃ and the preheating time is 1.5 h to form the second raw material. The refined melt from step S2 is heated to 850℃, and the second raw material is pressed into the melt by a bell jar. The melt is held at 850℃ for 60 min and then stirred. The melt is then allowed to cool to 750℃, the oxide scale is removed, and the melt is poured into a mold preheated to 200℃ to obtain the aluminum-copper alloy.

[0075] Comparative Example 3

[0076] This embodiment provides an in-situ particle-reinforced aluminum-copper alloy and its preparation method. The aluminum-copper alloy has the following composition by weight percentage: Cu: 7.0%; Mn: 0.4%; Cd: 0.35%; Zr: 0.2%; Ti: 0.25%; V: 0.1%; B: 0.05%; Ce: 1.0%, with the balance being Al.

[0077] The specific preparation method of the aluminum-copper alloy includes:

[0078] S1. According to the alloy composition ratio, Cu, Mn, Zr, and V elements in the alloy are added in the form of Al-Cu (Cu content 50 wt.%), Al-Mn (Mn content 10 wt.%), Al-Zr (Zr content 10 wt.%), and Al-V (V content 10 wt.%) master alloys, respectively. Al and Cd are added in the form of pure metals. After the raw materials are prepared, they are preheated at 120℃ for 1.5 hours to form the first raw material.

[0079] S2. The first raw material is heated and melted to form a melt, which is then allowed to cool to 750°C. 1.0% of the total mass of the alloy is added to the melt to refine it, and slag is removed by skimming with a slag skimmer.

[0080] S3. A pre-weighed mixture of K2TiF6 powder (Ti content 0.5 wt.%), KBF4 powder (B content 1 wt.%), and CeO2 powder (Ce content 1.0 wt.%) is mixed evenly at room temperature and preheated by wrapping with aluminum foil. The particle size of K2TiF6 powder, KBF4 powder, and CeO2 powder is 1.0 μm. The preheating temperature is 120°C and the preheating time is 1.5 h to form the second raw material. The refined melt from step S2 is heated to 850°C, and the second raw material is pressed into the melt by a bell jar. The melt is held at 850°C for 60 min and then stirred. The melt is then allowed to cool to 750°C, the oxide scale is removed, and the melt is poured into a mold preheated to 200°C to obtain the aluminum-copper alloy.

[0081] Performance testing

[0082] The mechanical properties of the cast aluminum-copper alloys obtained in Examples 1-4 and Comparative Examples 1-3 were tested, with tensile strength and elongation tested according to standard GB / T 228.1-2010. The test results are shown in Table 1.

[0083] Table 1 Mechanical Properties

[0084] Example 1 160.7 10.8 Example 2 153.2 8.2 Example 3 161.0 10.7 Example 4 156.2 9.0 Comparative Example 1 152.7 3.5 Comparative Example 2 146.3 5.4 Comparative Example 3 143.9 5.7

[0085] As can be seen from Table 1 above, the mechanical properties of the cast aluminum-copper alloys prepared in Examples 1-4 are all better than those of the cast aluminum-copper alloys prepared in the comparative examples, indicating that adding in-situ TiB2 particles containing CeO2 to aluminum-copper-aluminum alloys can indeed improve the mechanical properties of the cast alloys.

[0086] Figure 2 The metallographic structures of the cast aluminum-copper alloys prepared in Example 1 and Comparative Examples 1-3 are shown. Figure 2 (a) is a metallographic diagram of the cast aluminum-copper alloy prepared in Comparative Example 1, in which no TiB2 particles were formed; Figure 2(b) is a metallographic diagram of the cast aluminum-copper alloy prepared in Comparative Example 2, in which 0.5% TiB2 particles were formed; Figure 2 (c) is a metallographic diagram of the cast aluminum-copper alloy prepared in Example 1, in which 0.5% TiB2 particles + 0.5% CeO2 are formed; Figure 2 (d) is the metallographic structure of the as-cast aluminum-copper alloy prepared in Comparative Example 3, which contains 0.5% TiB2 particles and 1.0% CeO2. Figure 2 As can be seen, in the present invention, by adding a powder mixture of K2TiF6, KBF4 and CeO2 to the aluminum-copper-aluminum alloy, a dispersed precipitate phase is formed in the alloy, which at the same time refines the alloy grains and reduces the dendrite spacing.

[0087] Figure 3 Scanning electron microscopy (SEM) images of the as-cast aluminum-copper alloys prepared in Example 1 and Comparative Examples 1-3 are shown. Figure 3 (a) is a scanning electron microscope image of the as-cast aluminum-copper alloy prepared in Comparative Example 1;

[0088] Figure 3 (b) Scanning electron microscopy image of the as-cast aluminum-copper alloy prepared in Comparative Example 2; Figure 3 (c) Scanning electron microscope microstructure of the cast aluminum-copper alloy prepared in Example 1; Figure 3 (d) is a scanning electron microscope (SEM) image of the as-cast aluminum-copper alloy prepared in Comparative Example 3. Figure 3 It can be seen that the addition of 0.5 wt.% Ce element will change the morphology of Al2Cu and Al6Mn second phase at the grain boundary from a continuous network to a discontinuous framework.

[0089] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An in-situ particulate reinforced aluminium copper alloy, characterised in that: The aluminum-copper alloy, by weight percentage, comprises the following components: 6.0% < Cu < 7.5%, 0.3% < Mn < 0.5%, 0.2% < Cd < 0.5%, 0.1% < Zr < 0.3%, 0.05% < Ti < 0.5%, 0 < V < 0.2%, 0.005 < B < 0.5%, 0 < Ce < 0.5%, with the balance being Al; The preparation method of the in-situ particle-reinforced aluminum-copper alloy includes the following steps: S1. According to the alloy composition ratio, the raw materials corresponding to Cu, Mn, Zr, V, Al and Cd are mixed and preheated to form the first raw material; S2. Heat the first raw material to melt it into a melt, let it stand and cool to 740-760℃, and then refine the melt. S3. Mix the raw materials corresponding to Ti, B and Ce and preheat them to form the second raw material; heat the refined melt in step S2, add the second raw material to the melt and stir, then let it stand and cool to 740-760°C, and cast it to obtain the aluminum-copper alloy. In step S3, Ti, B, and Ce are mixed and preheated in the form of K2TiF6 powder, KBF4 powder, and CeO2 powder, respectively, and then added to the melt. The refined melt is heated to 820-880℃, the second raw material is added to the melt, and the temperature is maintained at 820-880℃ for 40-80 minutes before stirring. The aluminum-copper alloy includes: dispersed in-situ TiB2 particles, and Al2Cu and Al6Mn second phases distributed in a discontinuous skeleton shape.

2. An in-situ particulate reinforced aluminium copper alloy as claimed in claim 1, wherein: In step S1, Cu, Mn, Zr, and V are added in the form of Al-Cu alloy, Al-Mn alloy, Al-Zr alloy, and Al-V alloy, respectively. The Al-Cu alloy contains 45-55 wt.% Cu, the Al-Mn alloy contains 8-12 wt.% Mn, the Al-Zr alloy contains 8-12 wt.% Zr, and the Al-V alloy contains 8-12 wt.% V. Al and Cd are added in the form of pure metals.

3. The in-situ particle-reinforced aluminum-copper alloy as described in claim 1, characterized in that: In step S1, the preheating temperature is 100-140℃ and the preheating time is 1-2 hours.

4. The in-situ particle-reinforced aluminum-copper alloy as described in claim 1, characterized in that: In step S2, refining specifically includes adding 0.5-1.5% of hexachloroethane by mass of the total alloy to the melt for refining.

5. The in-situ particle-reinforced aluminum-copper alloy as described in claim 1, characterized in that: The particle size of the K2TiF6 powder, KBF4 powder, and CeO2 powder is 0.5-1.5 μm.

6. The in-situ particle-reinforced aluminum-copper alloy as described in claim 1, characterized in that: The K2TiF6 powder contains 0.4-0.6 wt.% Ti, the KBF4 powder contains 0.8-1.2 wt.% B, and the CeO2 powder contains 0.4-0.6 wt.% Ce.

Images