Preparation method of metal composite part

Abstract

According to the preparation method of the metal composite part, the metal composite part comprises a first metal part and a second metal part, and the preparation method comprises the steps that the semi-solid second metal part and the solid first metal part are subjected to die-casting forming, and a first intermediate is obtained; the first intermediate is subjected to first heat treatment, the second metal part is homogenized, the temperature of the first heat treatment ranges from 400 DEG C to 420 DEG C, the time ranges from 8 h to 12 h, and a second intermediate is obtained; and the second intermediate is subjected to solid solution treatment, the second intermediate subjected to solid solution treatment is hardened, and the metal composite part is obtained. Wherein the first heat treatment is beneficial to promoting the homogenization process between the first metal piece and the second metal piece which are subjected to die-casting forming, so that the binding force between the metal pieces is improved, the burning loss defect of the metal pieces caused by subsequent solid solution treatment is reduced, and the mechanical strength and hardness of the hardened metal pieces are improved.

Description

Technical Field

[0001] This application relates to the field of metal casting, and specifically to a method for preparing a metal composite. Background Technology

[0002] To combine different types of metals, existing technologies typically employ slurry die casting, where one metal part is embedded in a through-hole or grooved structure of another metal part to form a composite. However, the die casting process affects the mechanical properties of the metal parts, a defect that current die casting technologies have not yet overcome, and they offer limited improvement in the bonding strength between the metal parts. Summary of the Invention

[0003] In view of this, this application provides a method for preparing a metal composite to solve at least one of the above-mentioned technical problems.

[0004] This application provides a method for preparing a metal composite, the metal composite including a first metal part and a second metal part. The preparation method includes: die-casting a semi-solid second metal part and a solid first metal part to obtain a first intermediate; subjecting the first intermediate to a first heat treatment to homogenize it, the first heat treatment being performed at a temperature of 400 ℃ to 420 ℃ for 8 h to 12 h to obtain a second intermediate; and subjecting the second intermediate to a solution treatment to harden it to obtain the metal composite.

[0005] In some possible implementations, the second intermediate is solidified by a second heat treatment at a temperature of 515 °C to 525 °C for 4 h to 12 h.

[0006] In some possible implementations, the second intermediate after solution treatment is hardened by a third heat treatment at a temperature of 180 °C to 185 °C for 4 h to 16 h.

[0007] In some possible implementations, the second heat treatment takes 8 to 10 hours.

[0008] In some possible implementations, the third heat treatment takes 8 to 14 hours.

[0009] In some possible implementations, the solid fraction of the second metal part is 40% to 60% during die casting.

[0010] In some possible implementations, before die casting, the preparation method further includes: eccentrically stirring a second metal part, wherein the temperature of the second metal part is 650 ℃ to 680 ℃, the rotation speed of the eccentric stirring is 175 rpm to 185 rpm, and the radius of the eccentric stirring is 15 mm to 20 mm.

[0011] In some possible implementations, the temperature of the first metal part is 150 ℃ to 200 ℃ during die casting.

[0012] In some possible implementations, die casting is performed inside a mold at a temperature of 270°C to 320°C.

[0013] In some possible implementations, the injection pressure for die casting is 700 MPa to 900 MPa, the injection speed is 3 m / s to 4 m / s, and the injection time is 0.04 s to 0.1 s.

[0014] In some possible implementations, the surface of the first metal part is provided with micropores, and a partially semi-solid second metal part is embedded in the micropores by die casting. The micropores are formed sequentially by chemical etching and laser etching, and the size of the holes formed by chemical etching is increased by laser etching.

[0015] In some possible implementations, the first metal component includes titanium and the second metal component includes aluminum.

[0016] Before performing solution treatment on the first and second metal parts after die casting, this application conducts a first heat treatment at a preset temperature and time. This facilitates the homogenization process between the first and second metal parts after die casting, reduces segregation caused by solid-liquid coexistence, and allows for more uniform bonding of metal components. It also reduces element aggregation between dendrites and grain boundaries, resulting in a uniform and stable microstructure. Furthermore, it helps improve the bonding force between the metal parts, giving the metal composite higher tensile strength, ductility, and fatigue life. It reduces stress concentration and crack initiation caused by segregation, improves the stability of subsequent plastic forming and machining, reduces electrochemical differences caused by element segregation, enhances the metal composite's resistance to localized corrosion, and helps improve the stability of the microstructure and properties of batch products, thereby increasing process reliability and finished product yield.

[0017] Furthermore, the homogenization process promoted by the first heat treatment at the preset temperature and time can reduce potential burn-off problems caused by compositional segregation in metal parts, thereby helping to reduce burn-off defects caused by subsequent solution treatment. Therefore, the preparation method of this application effectively solves the segregation problem commonly found in semi-solid die-cast aluminum alloys, thereby obtaining metal composite parts with uniform structure, excellent performance, and stable quality. Attached Figure Description

[0018] Figure 1 This is a metallographic image of semi-solid aluminum after die casting during the preparation process of Example 1 of this application.

[0019] Figure 2This is a metallographic image of semi-solid aluminum after heat treatment during the preparation process of Example 1 of this application.

[0020] Figure 3 This is a metallographic image of the fully liquid aluminum after die casting, as shown in Test Example 1 of this application.

[0021] Figure 4 The results show the yield strength and tensile strength of the aluminum-magnesium-silicon alloy in Test Example 2 of this application.

[0022] Figure 5 The shear strength test results are for the semi-solid aluminum joint in Test Example 3 of this application.

[0023] Figure 6 The results show the hardness and burn-off defect test results of the metal composite parts obtained by the preparation methods of Examples 1-9 of this application.

[0024] Figure 7 This is a macroscopic metallographic image of the metal composite obtained by the preparation method of Example 5 of this application.

[0025] Figure 8 The hardness test results are for the metal composite parts obtained by the preparation methods of Comparative Examples 1-13 of this application.

[0026] Figure 9 The image shows the microstructure of the metal composite obtained by the preparation method of Comparative Example 13 of this application.

[0027] Figure 10 This is a macroscopic metallographic image of the metal composite obtained by the preparation method of Comparative Example 13 of this application.

[0028] Figure 11 The hardness and burn-off defect test results are for the metal composite parts obtained by the preparation methods of Comparative Examples 1-3 of this application. Detailed Implementation

[0029] The embodiments of this application are described in detail below. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application; it should be noted that, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; where there is no conflict, the implementation methods and features of the implementation methods of this application can be combined with each other; many specific details are set forth in the following description to provide a full understanding of this application, and the described implementation methods are only a part of the implementation methods of this application, and not all of the implementation methods.

[0030] One embodiment of this application provides a method for preparing a metal composite component, the metal composite component including a first metal component and a second metal component, the preparation method comprising: Step 1: Die-cast the semi-solid second metal part and the solid first metal part to obtain the first intermediate body.

[0031] In some embodiments, during die casting, the solid fraction of the second metal part is 40% to 60%. For example, during die casting, the solid fraction of the second metal part can be 40%, 42%, 44%, 46%, 48%, 50%, 52%, 54%, 56%, 58%, 60%, or any value within the range of any two of the above values. Controlling the solid fraction of the semi-solid second metal part within the above range during die casting is beneficial for promoting the flow of the semi-solid second metal part and for maintaining a high solid content, thereby improving the mechanical properties of the second metal part (such as aluminum) and maintaining good tensile strength and yield strength.

[0032] In some embodiments, the temperature of the first metal part during die casting is between 150°C and 200°C. For example, the temperature of the first metal part during die casting can be 150°C, 155°C, 160°C, 165°C, 170°C, 175°C, 180°C, 185°C, 190°C, 195°C, 200°C, or any value within the range of any two of the above values. This application has found that, taking titanium-aluminum composite die casting as an example, the titanium material is in direct contact with the high-temperature molten aluminum. If the temperature of the titanium material is too low, the rapid solidification of the molten aluminum due to a sudden and intense temperature difference may affect the interface filling, or thermal stress concentration may cause microcracks or delamination at the interface, or insufficient interface diffusion reaction may affect the metallurgical bonding strength. In this application, preheating the first metal part to the above-mentioned temperature during die casting can effectively reduce the temperature gradient between the titanium material and the molten aluminum, which is beneficial to reducing shrinkage when the first metal part and the second metal part are joined, making the interface heat transfer and element diffusion more balanced. This temperature range can prevent the formation of excessive oxide film on the surface of titanium materials, and also promote the diffusion and wetting of aluminum elements on the surface of titanium substrate, which is conducive to the formation of a tight and uniform metallurgical bonding layer.

[0033] In some embodiments, die casting is performed within a mold at a temperature of 270°C to 320°C. For example, the mold temperature can be 270°C, 275°C, 280°C, 285°C, 290°C, 295°C, 300°C, 305°C, 310°C, 315°C, 320°C, or any value within a range of any two of the above values. By controlling the mold temperature within the above range, preheating allows the surface of the first metal part (e.g., titanium) to make more thorough contact with the second metal part (e.g., molten aluminum) when the first metal part is placed in the mold. This enhances the wetting ability of the molten aluminum on the titanium surface, reduces the formation of porosity and defects, and simultaneously, at a suitable temperature, allows aluminum atoms to diffuse moderately along the titanium surface, promoting the formation of a thin and uniform reaction layer (e.g., intermetallic compounds such as TiAl3), thus improving the interfacial bonding strength. By properly preheating the first metal part and its mold, it is beneficial to reduce transient thermal stress, reduce the risk of interface cracking, delamination and early failure of die castings, and also improve the interface bonding state, thereby improving the overall mechanical properties (tensile strength, fatigue life), airtightness and corrosion resistance of the composite part.

[0034] In some embodiments, the injection pressure for die casting is 700 MPa to 900 MPa, the injection speed is 3 m / s to 4 m / s, and the injection time is 0.04 s to 0.1 s. For example, the injection pressure for die casting can be 700 MPa, 720 MPa, 74 MPa, 760 MPa, 780 MPa, 800 MPa, 820 MPa, 840 MPa, 860 MPa, 880 MPa, 900 MPa, or any value within the range of any two of the above values. The injection speed can be 3 m / s, 3.1 m / s, 3.2 m / s, 3.3 m / s, 3.4 m / s, 3.5 m / s, 3.6 m / s, 3.7 m / s, 3.8 m / s, 3.9 m / s, 4 m / s, or any value within the range of any two of the above values. The injection time can be 0.04 s, 0.05 s, 0.06 s, 0.07 s, 0.08 s, 0.09 s, 0.1 s, or any value within the range of any two of the above values. This application finds that, taking titanium-aluminum composite die casting as an example, the semi-solid aluminum alloy is in a solid-liquid coexistence state and exhibits thixotropy. Its fluidity is highly sensitive to injection pressure. Insufficient injection pressure may lead to insufficient flow of the semi-solid slurry, affecting filling the mold cavity and easily causing shrinkage cavities, porosity, or incomplete filling defects. It may also affect contact with the titanium surface, resulting in insufficient interfacial wettability and affecting the strength of the titanium-aluminum bond. Conversely, excessive injection pressure may increase the risk of severe breakage of solid agglomerates in the semi-solid slurry, affecting the stability of the metallographic structure. Furthermore, excessive reaction may occur at the metal interface, potentially forming a brittle layer (such as a thick TiAl3 compound), affecting interfacial strength. High-pressure impact may also cause the titanium material to shift or the interface to peel off. The injection pressure controlled within the aforementioned range in this application helps the semi-solid slurry to fill the mold cavity quickly and uniformly, avoiding defects such as shrinkage cavities, porosity, and cold shuts, improving forming accuracy, and promoting sufficient wetting and diffusion of the aluminum liquid onto the titanium surface. This facilitates the formation of a thin and uniform intermetallic compound layer, strengthens the metallurgical bond at the titanium-aluminum interface, reduces the risk of excessive interfacial reaction or the formation of a thick, brittle compound layer due to excessive pressure, and improves interfacial bonding strength and toughness. This results in a metal composite part with a strong interface and dense structure, improving overall tensile strength, fatigue life, and corrosion resistance. Furthermore, it enhances the consistency of filling state and interfacial bonding quality among different batches of die castings, improving process repeatability and yield. By controlling the injection pressure, injection speed, and injection time within the aforementioned range, this application ensures that the semi-solid slurry fills at a reasonable speed, which improves fluidity, promotes complete mold cavity filling, and facilitates a tight and stable metallurgical bond with the titanium interface.

[0035] In some embodiments, before die casting, the preparation method further includes: eccentrically stirring a second metal part, wherein the temperature of the second metal part is 650°C to 680°C, the rotation speed of the eccentric stirring is 175 rpm to 185 rpm, and the radius of the eccentric stirring is 15 mm to 20 mm. For example, the temperature of the second metal part can be 650°C, 655°C, 660°C, 665°C, 670°C, 675°C, 680°C, or any value within the range of any two of the above values. The rotation speed of the eccentric stirring can be 175 rpm, 176 rpm, 177 rpm, 178 rpm, 179 rpm, 180 rpm, 181 rpm, 182 rpm, 183 rpm, 184 rpm, 185 rpm, or any value within the range of any two of the above values. The radius of the eccentric stirring can be 15 mm, 15.5 mm, 16 mm, 16.5 mm, 17 mm, 17.5 mm, 18 mm, 18.5 mm, 19 mm, 19.5 mm, 20 mm, or any value within the range of any two of the above values. This application finds that, taking titanium-aluminum composite die casting as an example, the melt cooling rate and stirring conditions during aluminum slurry preparation have a decisive influence on the grain morphology and uniformity of the semi-solid slurry. If the temperature is too high, the liquid phase ratio is too large, the semi-solid thixotropy is insufficient, making it difficult to maintain uniform suspension, and easily leading to coarse dendrites and segregation. If the temperature is too low, the solid phase content is too high, the slurry fluidity decreases, filling the mold cavity is difficult, and the wettability of the interface and titanium material is affected. Eccentric stirring can form an asymmetric flow field and shear force field within the melt, causing the primary grains to be broken and resuspended under shear action, promoting grain refinement and spheroidization. If the eccentric radius is too small, insufficient shearing may affect grain spheroidization; if the eccentric radius is too large, the flow field is too intense, easily introducing eddies and pores, affecting slurry stability. This application controls the aforementioned temperature and eccentric stirring conditions to obtain a uniform spherical or near-spherical grain structure, ensuring the slurry possesses good thixotropy and stable flowability, while simultaneously considering shearing and uniform mixing effects. This achieves a fine, equiaxed, and uniformly distributed semi-solid grain structure, and is beneficial for forming a second metal part with a specific solid fraction. By synergistically controlling the slurry temperature and eccentric stirring radius, it helps generate uniform spherical or near-spherical grains, avoids coarse dendrites, improves the thixotropy and flow stability of the slurry, and enables the semi-solid slurry to possess good flow characteristics, quickly and uniformly filling the mold cavity and reducing defects such as shrinkage cavities, cold shuts, and pores. The uniform and stable semi-solid slurry can fully contact the preheated titanium material, enhancing wettability and diffusion, and forming a dense and stable metallurgical bonding layer. This results in metal composites with fine microstructure and strong interfaces, improving tensile strength, fatigue life, and corrosion resistance. By controlling the temperature and eccentricity radius, the stability of the slurry preparation process can be improved, increasing the consistency of quality between different batches of metal composites and raising the yield rate.

[0036] In some embodiments, the surface of the first metal part is provided with micropores, and a partially semi-solid second metal part is embedded in the micropores by die casting. Adding micropores to the surface of the first metal part can increase the surface area of ​​the metal surface of the first metal part, which is beneficial to providing additional interlocking force, so that when the second metal part is embedded in these micropores by die casting, it can form a good bond with the first metal part.

[0037] In some embodiments, micropores are formed sequentially by chemical etching and laser etching, with laser etching increasing the size of the pores formed by chemical etching. Chemical etching or laser etching allows for more controllable micropore processing on the surface of a first metal part, and facilitates the efficient formation of multiple micropores, increasing the surface area of ​​the first metal part and thus improving bonding strength. As an example, using chemical etching to initially form micropores on the first metal part is beneficial for increasing the number and distribution range of surface structures on the first metal part, improving the machinability of subsequent laser etching, and reducing the risk of cracking of the first part that might result from direct laser etching on its surface. Laser etching of the micropores increases the size of some of them. Laser etching of the micropores formed by chemical etching can widen or deepen the micropores, increasing their size, which is beneficial for creating complex irregular structures on the surface of the part, generating higher interlocking forces, and improving the bonding strength between the two metal parts. Laser etching is performed on multiple points on the surface of the first metal part where the micropores are formed, with the density of the points being greater than the density of the micropores. By controlling the density of laser etching sites to be greater than the density of micropores, the laser etching can basically cover the micropores of chemical etching, which is conducive to promoting the widening or deepening of chemically etched micropores, thereby improving the complexity of irregular structures on the surface of the component.

[0038] In some embodiments, the first metal component comprises titanium, and the second metal component comprises aluminum. Understandably, the first metal component can be made of titanium, such as titanium bars; and the second metal component can be made of aluminum, such as aluminum ingots. The metal composite component preparation method of this application is applicable to titanium and aluminum composite components, wherein semi-solid aluminum and titanium are combined by die casting, and titanium and aluminum can form a good bond.

[0039] Step Two: The first intermediate is subjected to a first heat treatment to homogenize it. The temperature of the first heat treatment is 400℃ to 420℃, and the time is 8 h to 12 h, to obtain the second intermediate. For example, the temperature of the first heat treatment can be 400℃, 402℃, 404℃, 406℃, 408℃, 410℃, 412℃, 414℃, 416℃, 418℃, 420℃, or any value within the range of any two of the above values. The time of the first heat treatment can be 8 h, 8.5 h, 9 h, 9.5 h, 10 h, 10.5 h, 11 h, 11.5 h, 12 h, or any value within the range of any two of the above values.

[0040] Performing a first heat treatment at a preset temperature and time promotes homogenization between the first and second metal parts after die casting, reducing segregation caused by solid-liquid coexistence flow. This results in a more uniform bonding of metal components, reduces element aggregation at dendrites and grain boundaries, and achieves a uniform and stable microstructure. It also helps improve the bonding strength between the metal parts, giving the metal composite higher tensile strength, ductility, and fatigue life. Furthermore, it reduces stress concentration and crack initiation caused by segregation, improves the stability of subsequent plastic forming and machining, reduces electrochemical differences caused by element segregation, enhances the metal composite's resistance to localized corrosion, and helps improve the stability of the microstructure and properties of batch products, increasing process reliability and finished product yield. In addition, the homogenization process promoted by this first heat treatment at the preset temperature and time can reduce potential burn-off problems caused by component segregation in the metal parts, thereby helping to reduce burn-off defects caused by subsequent solution treatment.

[0041] Understandably, before homogenization, the first and second metal parts after die casting exhibit significant elemental segregation, coarse microstructure, and large performance fluctuations. For example, during semi-solid die casting, due to the difference in fluidity between the solid and liquid phases, interdendritic segregation and uneven microstructure are easily generated within the aluminum matrix, and intermetallic compounds (such as TiAl3) at the interface may exhibit uneven distribution, with localized thickening or insufficient continuity. Grain morphology varies, with coarse dendrites and fine grains coexisting, resulting in overall unstable microstructure. The interface bonding layer may contain pores, microcracks, or stress concentration areas. These pores, microcracks, or stress concentration areas in the interface bonding layer, along with localized stress concentration, lead to easy crack initiation and insufficient batch-to-batch quality consistency. After homogenization as described in this application, the first and second metal parts after die casting undergo prolonged heat treatment, allowing alloying elements to fully diffuse between the solid phase and the interface, significantly reducing segregation. The interface compound layer becomes more uniform and continuous, avoiding excessively thick localized brittle layers and enabling a more uniform redistribution of elements. Simultaneously, the reduced grain size difference results in a finer, equiaxed, and uniformly distributed metallographic structure. Residual stress is released, and the tendency for porosity and cracking is reduced, leading to a more homogenized microstructure. Furthermore, tensile strength, ductility, and fatigue life are significantly improved, the titanium-aluminum interface is more robust, the risk of peeling and cracking is reduced, and the overall resistance to localized corrosion is enhanced due to the weakened electrochemical differences, thereby reducing performance fluctuations and significantly improving the performance stability of each batch of products.

[0042] Understandably, controlling the temperature and time of the first heat treatment within the aforementioned range is beneficial for promoting the expected homogenization process between the first and second metal parts after die casting. When the temperature or time is below the preset values, insufficient homogenization is manifested as reduced bonding strength between the metal parts, severe burn-off defects, and poor mechanical properties. When the temperature or time is above the preset values, the changes in the metal parts are similar to those of direct solution treatment, resulting in reduced bonding strength between the metal parts, severe burn-off defects, and poor mechanical properties.

[0043] Step 3: Perform a solution treatment on the second intermediate to harden it and obtain a metal composite.

[0044] In some embodiments, the second intermediate is subjected to a second heat treatment to induce a solution, wherein the temperature of the second heat treatment is between 515°C and 525°C, and the time is between 4 h and 12 h. For example, the temperature of the second heat treatment can be 515°C, 516°C, 517°C, 518°C, 519°C, 520°C, 521°C, 522°C, 523°C, 524°C, 525°C, or any value within the range of any two of the above values. The time of the second heat treatment can be 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h, 11 h, 12 h, or any value within the range of any two of the above values. In related technologies, taking titanium-aluminum composite die casting as an example, after semi-solid die casting, the aluminum alloy contains elements such as Mg, Si, and Cu, some of which are enriched in the interdendritic or interface regions, forming low-melting-point or brittle phases. Compositional segregation is usually eliminated through solution treatment, allowing elements to redisperse and dissolve into the α-Al matrix, improving compositional uniformity. This application controls the temperature and time of the second heat treatment within the aforementioned range, which helps promote the solidification process of the second intermediate, facilitates the elimination of compositional segregation, and promotes moderate element diffusion, making the interface layer structure more stable and reducing the adverse effects of microcracks or brittle structures, thereby improving interfacial bonding. Simultaneously, the aforementioned second heat treatment (solution treatment) of the Al-Mg-Si-Cu alloy can fully dissolve the forming elements of the strengthening phases (such as Mg2Si, Al2CuMg) into the matrix, providing sufficient dissolved atoms for subsequent aging precipitation, resulting in a uniform alloy matrix composition, avoiding localized brittleness, and improving the integrity and strength of the interfacial metallurgical bonding. This lays the foundation for subsequent aging treatment and significantly improves mechanical properties (strength, ductility, fatigue life).

[0045] In some embodiments, the second heat treatment time is 8 to 10 hours. For example, the second heat treatment time can be 8 hours, 8.3 hours, 8.6 hours, 8.9 hours, 9.2 hours, 9.5 hours, 9.8 hours, 10 hours, or any value within the range of any two of the above values. This application has found that, taking titanium-aluminum composite die casting as an example, element diffusion has its own kinetic requirements. At the solution temperature, the diffusion rates of Mg, Si, and Cu are limited, requiring sufficient time for them to completely dissolve into the matrix. If the time is too short, residual segregation and undissolved phases will remain, affecting the alloy strengthening effect. If the time is too long, grain growth will be significant, affecting plasticity and toughness. This application's research has found that the above-mentioned second heat treatment time can achieve a better balance between sufficient solution and avoiding excessive grain coarsening, thereby further improving the stability of the interfacial reaction. Within the above-mentioned time range, the diffusion of interfacial elements reaches equilibrium, which helps to generate a uniform and dense interfacial bonding layer and reduces the formation of excessively thick brittle intermetallic compounds. Controlling the time of the second heat treatment within the above range helps to fully dissolve the main alloying elements, reduce residual segregation or undissolved phases, maintain fine grains and uniform structure, further improve comprehensive mechanical properties, and is conducive to optimizing the titanium-aluminum interface bonding layer, which is both strong and does not deteriorate due to excessively thick brittle phases. It also helps to improve the performance stability and consistency of different batches of metal composites.

[0046] In some embodiments, the second intermediate after solution treatment is hardened by a third heat treatment at a temperature of 180°C to 185°C for a time of 4 h to 16 h. For example, the temperature of the third heat treatment can be 180°C, 181°C, 182°C, 183°C, 184°C, 185°C, or any value within the range of any two of the above values. The time of the third heat treatment can be 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h, 11 h, 12 h, 13 h, 14 h, 15 h, 16 h, or any value within the range of any two of the above values. Controlling the temperature and time of the third heat treatment within the above range helps to promote the age hardening process of the second intermediate, thereby enhancing the mechanical properties of the resulting composite metal part. In related technologies, taking titanium-aluminum composite die casting as an example, the Al-Mg-Si-Cu aluminum alloy mainly strengthens Mg2Si and a composite phase of Cu, Mg, and Si (such as Al2CuMg). After solution treatment, Mg, Si, and Cu are uniformly dissolved in the matrix. During aging, these solute atoms gradually precipitate and form fine, dispersed phases, which effectively prevent dislocation movement and produce precipitation strengthening. The temperature and time of the third heat treatment (aging treatment) in this application are controlled within the above-mentioned range, which improves the strength of the aluminum matrix, helps to disperse stress concentration near the titanium-aluminum interface, reduces the risk of peeling or microcracks, and at the same time, the appropriate distribution of precipitated phases can reduce micro-electrochemical differences, which is beneficial to improving resistance to localized corrosion. It also helps to improve tensile strength, fatigue life and wear resistance, maintain a certain degree of ductility, prevent excessive embrittlement due to the strengthening process, enhance the stability of the titanium-aluminum interface bonding, and improve the reliability of the overall structure.

[0047] In some embodiments, the duration of the third heat treatment is 8 h to 14 h, or any value within the range of any two of the above values. For example, the duration of the third heat treatment can be 8 h, 8.3 h, 8.6 h, 8.9 h, 9.2 h, 9.5 h, 9.8 h, 10.1 h, 10.4 h, 10.7 h, 11.1 h, 11.4 h, 11.7 h, 12 h, 12.3 h, 12.6 h, 12.9 h, 13.2 h, 13.5 h, 13.8 h, 14 h, or any value within the range of any two of the above values. Controlling the time of the third heat treatment within the aforementioned range allows for the formation of uniform and fine transition phases such as β″ and θ′, providing a better strengthening effect and thus contributing to further improvement in the hardness of the resulting metal composite. This time window strikes a balance between sufficient precipitation and avoiding coarsening, maximizing strength while maintaining good ductility and interfacial toughness. For example, 6013 aluminum alloy can achieve its optimal strengthening state, which is beneficial for promoting uniform microstructure and dispersed precipitates, obtaining a stable strength and toughness match, and improving the performance consistency of different batches of metal composites.

[0048] The present application's solution will be explained below with reference to embodiments. Those skilled in the art will understand that the following examples are for illustrative purposes only and should not be construed as limiting the present application. Unless otherwise stated, reagents, software, and instruments involved in the following embodiments that are not specifically mentioned are all conventional commercially available products or open-source materials.

[0049] Example 1: A method for preparing a metal composite component, comprising: Step 1: Provide aluminum ingot substrate, place the aluminum ingot into a melting crucible, heat the crucible to 800 ℃ to completely melt the aluminum ingot into a liquid state, adjust the crucible temperature to 720 ℃, and carry out refining and degassing at a constant temperature, controlling the rotation speed at 320 r / min and the flow rate at 10 Nm³. 3 At a pressure of 0.55 MPa and a duration of 17 min, degassing is performed twice under these conditions. 430 g to 450 g of the degassed liquid aluminum is cooled to 650 ℃ to 680 ℃ and eccentrically stirred for 30 s to 60 s at a speed of 175 rpm to 185 rpm and a radius of 15 mm to 20 mm to obtain aluminum with a solid phase content of 40% to 60%, which is used as the second metal part in the die casting process.

[0050] Step 2: Provide a titanium strip as the first metal part. Preheat the titanium strip to 150 ℃ to 200 ℃ and load it into a mold at 270 ℃ to 320 ℃. Die-cast the first metal part with the second metal part obtained in the first step. The injection speed of the die-casting is controlled at 3 m / s to 4 m / s, the injection pressure is controlled at 700 MPa to 900 MPa, and the injection time is controlled at 0.04 s to 0.1 s to obtain the first intermediate.

[0051] Step 3: The first intermediate is subjected to a first heat treatment at a temperature of 400 °C for 8 h to obtain the second intermediate.

[0052] Step 4: The second intermediate is solidified by a second heat treatment at a temperature of 515°C to 525°C for 4 hours.

[0053] Step 5: The second intermediate after solution treatment is hardened by a third heat treatment at a temperature of 180 °C for 4 h to obtain the metal composite.

[0054] Examples 2-9: The difference from Example 1 is that the first heat treatment, the second heat treatment, and the third heat treatment were performed according to the temperature and time shown in Table 1.

[0055] Comparative Examples 1-3: The difference from Example 1 is that the first heat treatment, the second heat treatment, and the third heat treatment were performed according to the temperature and time shown in Table 1.

[0056] Comparative Example 4-13: The difference from Example 1 is that the third step (i.e., the first heat treatment) is not performed, and the second and third heat treatments are performed according to the temperatures and times shown in Table 1.

[0057] Table 1. Preparation conditions of the metal composite parts preparation methods of Examples 1-9 and Comparative Examples 1-13 of this application This application analyzed the metallographic morphology of the semi-solid aluminum during the preparation process of the examples using Keyence-VHX microscopy. For example, please refer to Example 1. Figure 1 Semi-solid aluminum, after die casting, can form equiaxed grains with higher sphericity and reduced defects such as shrinkage cavities, thus improving the mechanical strength of the resulting metal composite parts. Please refer to [further details]. Figure 2After die casting and heat treatment, the aluminum structure in aluminum-containing parts is relatively uniform and dense. Therefore, using semi-solid aluminum for die casting can improve the mechanical strength of the resulting metal composite. In contrast, this application provides Test Example 1, which uses fully liquid aluminum for die casting. Please refer to [link to Test Example 1]. Figure 3 The metallographic structure of fully liquid aluminum after die casting exhibits a knitted morphology. During the forming process, shrinkage cavities may occur due to air entrapment, which is detrimental to the mechanical strength of the resulting metal composite.

[0058] This application also provides Test Example 2, which demonstrates the effects of fully liquid aluminum (0% solid content) and semi-solid aluminum (high solid content 40%~60%, low solid content 10%~30%) on yield strength and tensile strength using aluminum-magnesium-silicon alloys. Please refer to [link to relevant documentation]. Figure 4 Compared with conventional die casting (Conv DC), conventional die casting after heat treatment (Conv HT), high-solids-content die casting (SEED DC), high-solids-content die casting after heat treatment (SEED HT), low-solids-content die casting (GISS DC), and low-solids-content die casting after heat treatment (GISSHT), the high-solids-content die casting heat-treated aluminum-magnesium-silicon alloy exhibits higher yield strength and tensile strength. This application also provides Test Example 3, demonstrating the bonding of a 3D-printed surface lattice microstructure of titanium alloy with semi-solid aluminum. Please refer to [link to relevant documentation]. Figure 5 Due to the high mechanical properties of semi-solid aluminum, shear strength tests in different regions (A / B / C) of the joint showed that the joint has high bonding strength.

[0059] This application employs metallographic microscopy (Keyence-VHX) to perform metallographic analysis on the metal composites of Examples 1-9 and Comparative Examples 1-13, and uses ImageJ software to calculate burn-off defects. This application also performs hardness analysis on the metal composites of Examples 1-9 and Comparative Examples 1-13 using a Vickers hardness tester (Struers-DuraVersa 100). Please refer to the above analysis results. Figures 6 to 11 .

[0060] Please see Figure 6In embodiments 1-9 of this application, a first heat treatment is performed before the solution treatment of the first and second metal parts after die casting. This facilitates the homogenization process between the first and second metal parts, resulting in a more uniform bonding of the metal components and thus improving the bonding strength between the metal parts. Simultaneously, the homogenization process promoted by this first heat treatment can reduce potential burn-off problems caused by component segregation in the metal parts, thereby helping to reduce burn-off defects caused by subsequent solution treatment. Furthermore, the increased density of the metal components during the homogenization process promoted by this first heat treatment helps to improve the mechanical strength and hardness of the hardened metal parts. Therefore, the composite metal parts prepared by the method of this application exhibit good bonding strength at the joints and good mechanical properties.

[0061] For example, please refer to Embodiment 5. Figure 7 In the preparation process of the metal composite, the first heat treatment can reduce the burning defects caused by the subsequent solution treatment. Therefore, the metal structure of the metal composite in this application embodiment shows significantly fewer burning defects. In addition, in the embodiments of this application, Examples 5-6 further control the time of the second heat treatment within a preset range (8 h to 14 h), and found that the resulting metal composite has higher hardness.

[0062] Please see Figure 8 , Figure 9 and Figure 10 Taking Comparative Example 13 as an example, the metal composite obtained without the first heat treatment can also have good mechanical properties (such as...) under controlled specific preparation conditions. Figure 8 The hardness shown), but its metallographic structure at the microscopic level (such as the hardness shown), but its hardness at the microscopic level (such as the hardness shown). Figure 9 ) and macro (such as Figure 10 All of them showed a significant number of burn defects. (See also...) Figure 8 In Comparative Examples 4-10, and Comparative Examples 6-9, the time of the third heat treatment was further controlled within a preset range (8 h to 14 h), which can further improve the hardness of the resulting metal composite.

[0063] Please see Figure 11The temperatures of the first heat treatment in Comparative Examples 1-3 exceeded the preset range (the temperature in Comparative Example 1-2 was too high, and the temperature in Comparative Example 3 was too low). Software calculations showed that the metal composite parts still exhibited a certain percentage of burn-off defects. This indicates that controlling the temperature and time of the first heat treatment within the aforementioned range is beneficial for promoting the expected homogenization process between the first and second metal parts after die casting. When the temperature or time is lower than the preset values, insufficient homogenization is manifested as reduced bonding strength between the metal parts, severe burn-off defects, and poor mechanical properties. When the temperature or time is higher than the preset values, the changes in the metal parts are similar to those of direct solution treatment, with reduced bonding strength between the metal parts, severe burn-off defects, and poor mechanical properties.

[0064] The above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit it. Although this application has been described in detail with reference to the above preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions to the technical solutions of this application should not depart from the spirit and scope of the technical solutions of this application.

Claims

1. A method for preparing a metal composite component, the metal composite component comprising a first metal component and a second metal component, characterized in that, The preparation method includes: The semi-solid second metal part and the solid first metal part are die-cast to obtain a first intermediate body; The first intermediate is subjected to a first heat treatment to homogenize it. The first heat treatment is performed at a temperature of 400 °C to 420 °C for 8 h to 12 h to obtain the second intermediate. The second intermediate is subjected to a solution treatment to harden it, thereby obtaining the metal composite.

2. The preparation method according to claim 1, characterized in that, The preparation method satisfies at least one of the following conditions: (1) The second intermediate is subjected to a second heat treatment at a temperature of 515 °C to 525 °C for a time of 4 h to 12 h. (2) The second intermediate after solidification is hardened by a third heat treatment, wherein the temperature of the third heat treatment is 180 ℃ to 185 ℃ and the time is 4 h to 16 h.

3. The preparation method according to claim 2, characterized in that, The preparation method also satisfies at least one of the following conditions: (1) The duration of the second heat treatment is 8 to 10 hours; (2) The duration of the third heat treatment is 8 h to 14 h.

4. The preparation method according to claim 1, characterized in that, During the die casting process, the solid fraction of the second metal part is 40% to 60%.

5. The preparation method according to claim 4, characterized in that, Before the die casting process, the preparation method further includes: The second metal part is subjected to eccentric stirring, the temperature of the second metal part is 650 ℃ to 680 ℃, the rotation speed of the eccentric stirring is 175 rpm to 185 rpm, and the radius of the eccentric stirring is 15 mm to 20 mm.

6. The preparation method according to claim 1, characterized in that, During the die casting process, the temperature of the first metal part is between 150°C and 200°C.

7. The preparation method according to claim 6, characterized in that, The die casting is performed inside a mold at a temperature of 270°C to 320°C.

8. The preparation method according to claim 1, characterized in that, The injection pressure for the die casting process is 700 MPa to 900 MPa, the injection speed is 3 m / s to 4 m / s, and the injection time is 0.04 s to 0.1 s.

9. The preparation method according to claim 1, characterized in that, The surface of the first metal part is provided with micropores. The second metal part, which is partially semi-solid, is embedded in the micropores by the die casting process. The micropores are formed by chemical etching and laser etching in sequence. The laser etching increases the size of the holes formed by the chemical etching.

10. The preparation method according to any one of claims 1-9, characterized in that, The first metal component includes titanium, and the second metal component includes aluminum.

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