Wave-type semi-solid slurry preparation device and preparation method of high-toughness light-weight die-casting aluminum-silicon alloy structural component

Abstract

The invention discloses a wave type semi-solid slurry preparation device and a preparation method of a high-toughness light-weight die-casting aluminum-silicon alloy structural part, relates to the technical field of aluminum alloys, and solves the problems of poor plasticity and low strength of an existing aluminum-silicon alloy casting. The invention provides a wave-shaped semi-solid slurry preparation device capable of forcibly cooling molten metal and rapidly supercooling the molten metal to induce explosive nucleation, the cooling speed of the molten metal reaches 200-300 DEG C / s, then the device is adopted to prepare semi-solid slurry, and the semi-solid slurry is subjected to die-casting forming to obtain an aluminum-silicon alloy casting. The aluminum-silicon alloy casting is subjected to isothermal hot extrusion, and an aluminum-silicon alloy extrusion workpiece is obtained; and T6 heat treatment is conducted on the aluminum-silicon alloy extrusion part, and the high-toughness die-casting aluminum alloy structural part is obtained. By adopting the method disclosed by the invention, the microstructure of the aluminum-silicon alloy can be obviously improved, the mechanical property is improved, the aluminum-silicon alloy has high strength and good plasticity, and the balance of high strength and high plasticity of the aluminum-silicon alloy is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of die-cast aluminum alloys, and in particular to a device for preparing a wave-shaped semi-solid slurry and a method for preparing a high-strength, tough, and lightweight die-cast aluminum-silicon alloy structural part. Background Art

[0002] Al-Si alloy structural parts are widely used in major national economic and national defense construction fields such as aerospace, automobiles, high-speed railways, and ships due to their high specific strength, high hardness, low linear expansion coefficient, good thermal stability and excellent castability. In particular, they are used in the transportation field to manufacture and process engine cylinder blocks, steering knuckles, pistons and other components.

[0003] A356 alloy is a typical hypoeutectic Al-Si alloy, consisting of α-Al phase and eutectic Si phase. On the one hand, the rough and irregular intermetallic compounds and needle-shaped eutectic Si phases are highly brittle and cannot adapt to the plastic deformation of the surrounding soft and tough α-Al matrix, which will reduce the alloy's resistance to stress cracking. On the other hand, A356 alloy does not have obvious solid solution strengthening effects or elements that can combine with the α-Al matrix to form high-hardness intermetallic compound precipitates. This makes A356 alloy have problems with poor plasticity, low strength and extremely low toughness. This greatly limits the application of A356 alloy in scenarios with high strength, toughness and lightweight requirements.

[0004] A356 alloy can be processed using semi-solid processing technology, which combines the advantages of traditional forging and casting methods by solidifying the molten metal liquid to form a semi-solid alloy slurry and then performing die casting. Semi-solid slurry has good fluidity, low filling temperature, stable filling and fine microstructure. Semi-solid slurry has higher viscosity than full liquid and less gas entrapment. It has a certain effect on improving the performance of Al-Si alloys, but there are still certain defects: 1. When the aluminum-silicon alloy liquid metal is rapidly cooled to a certain degree, the degree of supercooling reaches a critical value, and the atoms or molecules in the liquid phase will quickly aggregate to form a large number of crystal nuclei. This phenomenon is called explosive nucleation. Among them, the cooling rate plays a key role. The faster the cooling rate, the greater the degree of supercooling of the metal liquid, and the higher the nucleation rate, which can significantly refine the grains, reduce structural defects, and improve the strength and toughness of the material. However, in the existing technology, the liquid phase content of the semi-solid slurry when filling the mold cavity is 40%-80%, and sometimes even close to 90%. After the remaining liquid phase fills the cavity, it undergoes secondary solidification and undergoes a new solidification process, that is, the secondary primary phase precipitates and reacts with the eutectic, resulting in solidification shrinkage and composition segregation, thereby causing defects such as shrinkage and thermal cracking, affecting the mechanical properties of the formed part.

[0005] 2. Iron (Fe), a common impurity in A356 alloy, can directly damage the mechanical and processing properties of the product. Due to the limited solubility of iron in aluminum, iron-rich intermetallic compounds, such as β-Al5FeSi phase and π-Al8FeMg3Si6 phase, are easily formed during the solidification of the molten metal to form a semi-solid alloy slurry. At low cooling rates, the Fe-rich intermetallic compounds tend to form needle-shaped β-Al5FeSi phases, which, together with the needle-shaped eutectic Si phase, increase the brittleness of the alloy, seriously affect its toughness, and have a negative impact on the alloy's strength improvement.

[0006] 3. The eutectic Si phase is mainly in the form of needles, rods or strips, and is unevenly distributed with sharp edges and corners, which seriously cut the alloy matrix. At the same time, the sharp edges and corners easily cause stress concentration, thus affecting the strength and plasticity of the alloy. Summary of the Invention

[0007] In order to solve the above technical problems, the present invention provides a wavy semi-solid slurry preparation device and a preparation method of high-strength, toughness and lightweight die-cast aluminum-silicon alloy structural parts. The wavy semi-solid slurry preparation device is used to force cool the aluminum-silicon alloy metal liquid, first prepare the semi-solid slurry, and then use horizontal die-casting to obtain a die-cast aluminum-silicon alloy structural part with medium strength and medium plasticity. Then, isothermal hot extrusion and T6 heat treatment are combined to significantly improve the microstructure of the die-cast aluminum-silicon alloy, achieve stable preparation of die-cast aluminum alloys for high-strength, toughness and lightweight structural parts, ensure the balance between high strength and high plasticity, and significantly improve the mechanical properties.

[0008] The present invention is achieved through the following technical solutions.

[0009] The first object of the present invention is to provide a wave-shaped semi-solid slurry preparation device, comprising: The wavy water-cooling slope is used to forcefully cool the molten metal to form a semi-solid slurry. The slope of the wavy water-cooling slope has grooves and protrusions, and the back of the protrusions is provided with a water cooling system. A pouring device is provided above the wave-shaped water-cooling slope and is used to pour the molten metal onto the slope surface of the wave-shaped water-cooling slope; The collecting device is located at the discharge port of the wave-shaped water-cooled slope and is used to collect the semi-solid slurry; The molten metal flows through the grooves of the wave-shaped water-cooling slope to be gathered, and then flows through the ridges of the wave-shaped water-cooling slope to undergo strong heat exchange, so that the cooling rate of the molten metal reaches 200-300°C / s.

[0010] The present invention provides a wave-shaped semi-solid slurry preparation device capable of forced cooling of molten metal, causing it to rapidly supercool and induce explosive nucleation. This device, combined with circulating water cooling and a wave-shaped cooling ramp, allows the aluminum-silicon alloy molten metal to undergo a strong, rapid chilling effect. The grooves of the wave-shaped water-cooling ramp concentrate, stabilize, and constrain the flow of the molten metal, ensuring that subsequent molten metal flowing over the protrusions maintains more concentrated and stable contact with the protrusions, thereby improving heat exchange and achieving a cooling rate of 200-300°C / s.

[0011] As the high-temperature molten metal flows through the wavy slope, the grooves in the wavy structure gather, stabilize, and constrain the flow of the high-temperature alloy molten metal. It then flows through the ridges in the wavy structure. Circulating cooling water is introduced into the water cooling system behind the ridges. Under the forced cooling effect of the circulating cooling water, intense heat exchange occurs, forcing the Al-Si alloy to undergo explosive nucleation, forming a special semi-solid slurry composed of spherical or near-spherical α-Al phases and a residual high-solute liquid phase. This effectively refines and homogenizes the microstructure of the aluminum-silicon alloy, while also inhibiting the formation of Fe-rich intermetallic compounds to a certain extent and preventing the growth of eutectic Si into coarse dendrites. Real-time measurements using two temperature detectors, one at the pouring cup and the other at the collection device, indicate cooling rates of 200-300°C / s.

[0012] Furthermore, the wavy water-cooling slope includes at least two sections of protrusions and two sections of grooves, with an overall length of not less than 400 mm. That is, it is set as a double wavy water-cooling slope, consisting of two sections of wavy protrusions of different sizes and two sections of grooves of different sizes, and the size of the second section is larger than that of the first section. In a specific embodiment, the length, arc radius and depth of the first section of the groove are 46 mm, 40 mm and 8 mm respectively; the length, arc radius and height of the first section of the wavy protrusion are 115 mm, 100 mm and 12 mm respectively; the length, arc radius and depth of the second section of the groove are 65 mm, 75 mm and 10 mm respectively; the length, arc radius and height of the second section of the wavy protrusion are 120 mm, 150 mm and 12 mm respectively. After long-term experimental exploration, it was found that in order to ensure the cooling effect, the overall length of the wavy water-cooling slope should be not less than 400 mm. In a specific embodiment, the overall length of the double wavy water-cooling slope is 440 mm.

[0013] When the molten metal flows through the first wavy slope, the first groove first gathers, stabilizes, and constrains the flow of the high-temperature alloy molten metal. Then, when it flows through the first protrusion, it produces an initial strong chilling effect under the forced cooling effect of the circulating cooling water on the back. Then, when the metal alloy molten metal with a low solid phase fraction flows through the second wavy slope, it further plays a gathering and stabilizing role with the second groove, and then flows through the second protrusion to produce strong heat exchange. At the same time, there is circulating cooling water on the back of the second protrusion, and the combined effect of the two produces a second forced cooling. Through two forced cooling heat exchanges, the alloy is forced to explode nucleation, forming a special semi-solid slurry composed of spherical or nearly spherical α-Al phase and a residual high-solute liquid phase. It effectively refines and homogenizes the microstructure of the A356 alloy, while suppressing the formation of Fe-rich intermetallic compounds to a certain extent.

[0014] Furthermore, the water cooling system comprises circulating cooling water pipes, and the back of the projections of the wavy water-cooling slope is provided with mounting grooves, into which the circulating cooling water pipes are fixed. The number of cooling water pipes to be installed must match the projections of the wavy structure. By providing recessed mounting grooves on the back of the projections, the installation stability of the cooling water pipes is ensured, and the contact between the cooling water pipes and the projections is made closer, thereby better achieving forced heat exchange. In one specific embodiment, for a double-wavy water-cooling slope, two sets of cooling water pipes are provided, namely, an upper circulating cooling water pipe and a lower circulating cooling water pipe.

[0015] Furthermore, the pouring device includes a pouring cup and a fixed plate. The fixed plate is located above the wave-shaped water-cooling slope, and the pouring cup is mounted on the fixed plate via a toggle clamp. The pouring cup is a preheated steel pouring cup with a frame having a rectangular opening on the side of the pouring cup. After the pouring cup is preheated, the frame with the rectangular opening on the side cooperates with the guide block to achieve correct positioning, and then the pouring cup is fixed to the fixed plate via the toggle clamp to complete the installation.

[0016] Furthermore, it also includes a guide column, a guide sleeve, and a horizontally movable guide plate. The bottom of the guide column is mounted on a fixed seat. The upper portion of the guide column is sleeved with a guide sleeve for driving the pouring cup to move up and down. The horizontally movable guide plate is mounted below the fixed plate. The side of the horizontally movable guide plate is slidably connected to the guide sleeve via a sliding groove to drive the pouring cup to move horizontally. The guide sleeve is bolted into the sliding groove on the side of the horizontally movable guide plate. By adjusting the bolts, the pouring cup, fixed plate, and horizontally movable guide plate can be moved horizontally as a whole. The guide column and the guide sleeve are bolted together. By adjusting the bolts, the pouring cup, fixed plate, and horizontally movable guide plate can be moved up and down as a whole. This design gives the pouring cup adjustability, thereby ensuring the relative position between the pouring cup and the wave-shaped water-cooling slope, suitable for various usage requirements.

[0017] Furthermore, the collection device includes a collection crucible, a high-temperature resistant pad, a handle, and a linear guide. The ends of the high-temperature resistant pad are connected to the linear guide for linear motion. The collection crucible is placed on the high-temperature resistant pad, and the high-temperature resistant pad is connected to a handle for pulling the high-temperature resistant pad and the collection crucible. The collection crucible is used to collect semi-solid slurry and is placed on the high-temperature resistant pad so as to align with the wavy water-cooled slope discharge port. The handle is fixed to the side of the high-temperature resistant pad by bolts, and the linear guide is connected to the fixed seat 2 by bolts. The collection device of the present invention can be pulled to facilitate the removal of materials after collection is completed.

[0018] Furthermore, the device of the present invention also includes an angle adjustment device for adjusting the inclination angle of the wavy water-cooling slope. The angle adjustment device includes multiple hinge seats, a self-locking cylinder, and a push rod. The self-locking cylinder is mounted on a fixed seat 1 via the hinge seat. The upper end of the wavy water-cooling slope is connected to the push rod of the self-locking cylinder via the hinge seat 1. The lower end of the wavy water-cooling slope is mounted on a support platform via a hinge seat 3. The support platform is provided on the fixed seat 1. During use, the push rod is moved by adjusting the air flow in and out of the self-locking cylinder, thereby driving the wavy water-cooling slope to rotate around the bottom hinge seat 3, thereby adjusting the angle between the wavy water-cooling slope and the horizontal plane, thereby controlling the cooling time of the molten metal flowing through the wavy water-cooling slope.

[0019] A second object of the present invention is to provide a method for preparing a high-strength, tough, and lightweight die-cast aluminum-silicon alloy structural part, comprising the following steps: A wave-shaped semi-solid slurry preparation device is used to rapidly supercool the aluminum-silicon alloy liquid to induce explosive nucleation, thereby obtaining an aluminum-silicon alloy semi-solid slurry with a cooling rate of 200-300°C / s. The semi-solid slurry of aluminum-silicon alloy is die-casted to obtain a die-cast aluminum-silicon alloy casting with medium strength and medium plasticity; Isothermal hot extrusion is performed on die-cast aluminum-silicon alloy castings to obtain die-cast aluminum-silicon alloy structural parts with high strength and medium plasticity; The die-cast aluminum-silicon alloy structural parts are subjected to T6 heat treatment to obtain high-strength, toughness and lightweight die-cast aluminum-silicon alloy structural parts.

[0020] The preparation method of the die-cast aluminum-silicon alloy provided by the present invention first controls the forced cooling rate of the aluminum-silicon alloy liquid metal to 200-300°C / s by using a wave-shaped semi-solid slurry preparation device, forces heat exchange on the metal liquid, and cools it quickly, forcing the alloy to explode and nucleate, forming a special semi-solid slurry in which a spherical or nearly spherical α-Al phase and a residual high-solute liquid phase coexist. The slurry can effectively refine and homogenize the microstructure of the Al-Si alloy, and at the same time, to a certain extent, inhibit the formation of Fe-rich intermetallic compounds, and prevent the eutectic Si from growing into a coarse dendritic structure, thereby preventing the eutectic Si from growing together with the Fe-rich intermetallic compounds. The process combines isothermal hot extrusion and T6 heat treatment to further eliminate micro defects generated during the rheo-die casting process, crush and refine the sharp-angled lath-shaped eutectic Si particles in the microstructure of the semi-solid casting, and make the eutectic Si phase evenly distributed in a spherical or nearly spherical shape around the α-Al phase. Finally, a high-strength and high-plasticity aluminum-silicon alloy with a uniform microstructure consisting of a primary α-Al phase and spherical or nearly spherical fine Si phases is prepared, achieving a balance between high strength and high plasticity in the aluminum-silicon alloy, resulting in an alloy with a tensile strength of >260 MPa and an elongation of >15%.

[0021] Therefore, the method of the present invention can significantly improve the microstructure of aluminum-silicon alloy, enhance its mechanical properties, and enable it to have high strength and good plasticity, so that it can be more widely used in fields requiring high strength and high plasticity. In addition, the preparation method is simple in process, stable in composition, and suitable for industrial production.

[0022] Furthermore, the process parameters of the isothermal hot extrusion are: hot extrusion pressure of 50-200 MPa, extrusion speed of 1-5 mm / s, extrusion time of 5-15 min, holding time of 5-120 min, and isothermal temperature of 200-400°C.

[0023] Furthermore, the T6 heat treatment includes solution treatment and artificial aging treatment; wherein the solution treatment is performed at a temperature of 400-600°C for 1.5-3 hours, and the artificial aging treatment is performed at a temperature of 100-200°C for 1.5-4 hours. The present invention employs a short T6 heat treatment, with a solution treatment time of ≤3 hours and an artificial aging treatment time of ≤4 hours. This shortens the treatment time compared to existing technologies and, combined with the subsequent isothermal hot extrusion process, reduces energy consumption while improving the mechanical properties of the casting.

[0024] In a specific embodiment, a method for preparing a high-performance aluminum-silicon alloy comprises the following steps: S1. Melt the aluminum-silicon alloy and hold the alloy at this temperature for 1-5 minutes. Then, lower the melt temperature to 685-705°C, perform purification treatment, and then naturally air-cool to 660-675°C to obtain silicon alloy liquid. The melting temperature is 715-745°C. The alloy is melted and held in a medium-frequency induction heating furnace. Hexachloroethane is used for purification, including degassing and slag removal. S2. Using a wave-shaped semi-solid slurry preparation device to rapidly supercool the aluminum-silicon alloy liquid to induce explosive nucleation, thereby obtaining an aluminum-silicon alloy semi-solid slurry at a cooling rate of 200-300°C / s; S3. die-casting the semi-solid aluminum-silicon alloy slurry to obtain a die-cast aluminum-silicon alloy casting having medium strength and medium plasticity; wherein the die-casting process parameters are: injection pressure of 105-155 MPa, filling speed of 10-25 mm / s, die-casting mold temperature of 185-450° C., and die-casting mold holding time of 2-4 minutes; S4. Perform isothermal hot extrusion on the die-cast aluminum-silicon alloy casting to obtain a die-cast aluminum-silicon alloy structural part with high strength and medium plasticity; wherein the process parameters of the isothermal hot extrusion are: hot extrusion pressure of 50-200 MPa, extrusion speed of 1-5 mm / s, extrusion time of 5-15 min, holding time of 5-120 min, and isothermal temperature of 200-400°C.

[0025] S5. Perform T6 heat treatment on the die-cast aluminum-silicon alloy structural part, wherein the T6 heat treatment includes solution treatment and artificial aging treatment; wherein, the solution treatment is performed at a temperature of 400-600° C. for 1.5-3 hours; and the artificial aging treatment is performed at a temperature of 100-200° C. for 1.5-4 hours, to obtain a high-strength, tough, and lightweight die-cast aluminum-silicon alloy structural part.

[0026] The third object of the present invention is to provide a die-cast aluminum-silicon alloy prepared by the above method.

[0027] Compared with the prior art, the present invention has the following advantages and beneficial effects: 1. The present invention provides a wave-shaped semi-solid slurry preparation device capable of forced cooling of molten metal, causing it to rapidly supercool and induce explosive nucleation. This device allows the molten metal to undergo a strong, rapid chilling effect under the combined action of circulating water cooling and a wave-shaped cooling slope. The grooves of the wave-shaped water-cooling slope can concentrate, stabilize, and constrain the flow of the molten metal, allowing subsequent molten metal to more concentratedly and stably contact the raised surface when flowing through the raised surface, thereby improving heat exchange and achieving a cooling rate of 200-300°C / s. 2. The preparation method of the high-strength and lightweight die-cast aluminum-silicon alloy structural parts provided by the present invention first controls the forced cooling rate of the aluminum-silicon alloy molten metal to 200-300℃ / s by adopting a wave-shaped semi-solid slurry preparation device, forces heat exchange on the molten metal, and cools it quickly, forcing the alloy to explode and nucleate, forming a special semi-solid slurry composed of spherical or nearly spherical α-Al phase and residual high solute liquid phase. It can effectively refine and homogenize the microstructure of the Al-Si alloy, and at the same time inhibit the formation of Fe-rich intermetallic compounds to a certain extent, and prevent the eutectic Si from growing into a coarse dendritic structure, thereby preventing the eutectic Si from growing together with the Fe-rich metal. The intercalated compounds increase the brittleness of the alloy; then, isothermal hot extrusion and T6 heat treatment are combined to further eliminate the micro defects generated in the semi-solid rheo-die casting process, crush and refine the sharp-angled lath-shaped eutectic Si particles in the microstructure of the semi-solid casting, and make the eutectic Si phase spherical or nearly spherical and dispersed around the α-Al phase, and the distribution is uniform; finally, a high-strength, tough and lightweight die-cast aluminum alloy structural component with uniform microstructure composed of primary α-Al phase and spherical or nearly spherical fine Si phase is prepared, achieving a balance between high strength and high plasticity of aluminum-silicon alloy, so that the tensile strength of the structural component is greater than 260MPa, and the elongation is greater than 15%. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the following briefly introduces the drawings required for use in the examples. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be considered as limiting the scope. A person of ordinary skill in the art can also derive other relevant drawings based on these drawings without inventive effort. In the drawings: Figure 1 This is a schematic structural diagram of a wave-type semi-solid slurry preparation device according to the present invention; Figure 2 A half-section diagram of the device for preparing a wave-shaped semi-solid slurry according to the present invention; Figure 3 It is a structural diagram of the wave-shaped water-cooled slope; Figure 4 It is a structural diagram of the upper circulating cooling water pipe and the lower circulating cooling water pipe; Figure 5 This is the microstructure of the A356 alloy ingot obtained in Comparative Example 1; Figure 6 This is the microstructure of the semi-solid casting of A356 alloy prepared in Example 2; Figure 7 This is the microstructure of the semi-solid casting of A356 alloy prepared in Example 3; Figure 8This is a microstructure diagram of the high-strength, lightweight, die-cast aluminum-silicon alloy structure prepared in Example 4; Figure 9 This is a microstructure diagram of the high-strength, tough, and lightweight die-cast aluminum-silicon alloy structure prepared in Example 5; Figure 10 The microstructure of the A356 alloy casting prepared in Comparative Example 2; Figure 11 The microstructure of the A356 alloy casting prepared in Comparative Example 3; Figure 12 The microstructure of the A356 alloy casting prepared in Comparative Example 4; Figure 13 The microstructure of the A356 alloy casting prepared in Comparative Example 5; Figure 14 Comparison of stress-strain curves of the die-cast A356 alloys prepared in Examples 4 and 5 and Comparative Examples 2-5.

[0029] Markings and corresponding parts names in the accompanying drawings: 1-elbow clamp, 2-fixed plate, 3-guide block, 4-cup, 5-guide sleeve, 6-horizontally movable guide plate, 7-hinge seat 1, 8-guide column, 9-push rod, 10-self-locking cylinder, 11-fixed seat 1, 12-hinge seat 2, 13-support table, 14-upper circulating cooling water pipe, 15-fixed seat 2, 16-handle, 17-high temperature resistant pad, 18-linear guide, 19-collecting crucible, 20-lower circulating cooling water pipe, 21-wave-shaped water-cooling slope. DETAILED DESCRIPTION

[0030] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the technical solutions in the embodiments of the present invention are clearly and completely described below in conjunction with the embodiments and drawings. Obviously, the schematic implementation methods of the present invention and their descriptions are only used to explain the present invention and are not intended to limit the present invention.

[0031] The following describes in detail embodiments of the present invention's wave-shaped semi-solid slurry preparation device, die-cast aluminum-silicon alloy, and preparation method, with appropriate reference to the accompanying drawings. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions may be omitted. This is done to avoid unnecessary redundancy and to facilitate understanding by those skilled in the art.

[0032] In the description of the present invention, the indicated orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the product of the application is conventionally placed when in use, or are the orientations or positional relationships conventionally understood by those skilled in the art. These are merely for the convenience of describing the present application and simplifying the description, and are not intended to indicate or imply that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limitations on the present application.

[0033] At the same time, the terms "dispose," "assemble," "connect," and "connect" should be understood broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to direct connections, indirect connections through an intermediary, or internal connections between two components. Those skilled in the art will understand the specific meanings of these terms in the present invention.

[0034] The "ranges" disclosed herein are defined in terms of lower and upper limits. A given range is defined by selecting a lower limit and an upper limit, and the selected lower and upper limits define the boundaries of the particular range. Ranges defined in this manner may be inclusive or exclusive and may be arbitrarily combined, i.e., any lower limit may be combined with any upper limit to form a range.

[0035] Unless otherwise specified, the terms "include" and "comprising" used in the present invention may be open-ended or closed-ended. For example, "include" and "comprising" may mean that other substances not listed may also be included or that only the listed substances are included.

[0036] Unless otherwise specified, all steps of the present invention may be performed sequentially or randomly, but are preferably performed sequentially.

[0037] The technical solution of the present invention is further described in detail below with reference to the embodiments.

[0038] It should be noted that the following examples use A356 alloy as an example. The wavy water-cooling slope in the wavy semi-solid slurry preparation apparatus uses a double-wavy water-cooling slope. The experimental methods used in the examples are conventional unless otherwise specified. All materials, reagents, methods, and instruments used, unless otherwise specified, are conventional in the art and are commercially available to those skilled in the art.

[0039] Example 1.

[0040] This embodiment provides a wave-shaped semi-solid slurry preparation device, such as Figure 1-4 As shown, including: The wavy water-cooling slope 21 is used to forcefully cool the molten metal to form a semi-solid slurry. The slope of the wavy water-cooling slope 21 has grooves and protrusions, and the back of the protrusions is provided with a water cooling system. A pouring device is provided above the wave-shaped water-cooling slope 21 and is used to pour the molten metal onto the slope surface of the wave-shaped water-cooling slope 21; A collecting device, provided at the outlet of the wave-shaped water-cooled slope 21, is used to collect the semi-solid slurry; The molten metal flows through the grooves of the wave-shaped water-cooling slope 21 to be gathered, and then flows through the ridges of the wave-shaped water-cooling slope 21 to undergo strong heat exchange, so that the cooling rate of the molten metal reaches 200-300°C / s.

[0041] The present invention provides a wave-shaped semi-solid slurry preparation device capable of forced cooling of molten metal, causing it to rapidly supercool and induce explosive nucleation. This device, combined with circulating water cooling and a wave-shaped cooling ramp, allows Al-Si molten metal to undergo a strong, rapid chilling effect. The grooves of the wave-shaped water-cooling ramp 21 concentrate, stabilize, and constrain the flow of the molten metal, ensuring that subsequent molten metal flowing through the protrusions maintains more concentrated and stable contact with the protrusions, thereby improving heat exchange and achieving a cooling rate of 200-300°C / s.

[0042] As the high-temperature molten metal flows through the wavy slope, the grooves within the undulating structure gather, stabilize, and constrain the flow of the high-temperature alloy. It then flows through the ridges within the wavy structure. Circulating cooling water flows through the water cooling system behind the ridges. This forced cooling creates intense heat exchange, forcing the Al-Si alloy to undergo explosive nucleation, forming a special semi-solid slurry composed of spherical or near-spherical α-Al phases and a residual high-solute liquid phase. This effectively refines and homogenizes the Al-Si alloy's microstructure while also somewhat suppressing the formation of Fe-rich intermetallic compounds. Real-time measurements using two temperature detectors, one at the pouring cup and the other at the collection device, indicate cooling rates of 200-300°C / s.

[0043] As a preference, Figure 3As shown, the wavy water-cooling slope 21 includes at least two sections of protrusions and two sections of grooves, with an overall length of no less than 400 mm. This means it is configured as a double-wavy water-cooling slope 21, consisting of two sections of wavy protrusions of different sizes and two sections of grooves of different sizes, with the second section being larger than the first. In one specific embodiment, the length, arc radius, and depth of the first section's groove are 46 mm, 40 mm, and 8 mm, respectively; the length, arc radius, and height of the first section's wavy protrusion are 115 mm, 100 mm, and 12 mm, respectively; the length, arc radius, and depth of the second section's groove are 65 mm, 75 mm, and 10 mm, respectively; and the length, arc radius, and height of the second section's wavy protrusion are 120 mm, 150 mm, and 12 mm, respectively. After long-term experimental exploration, it was found that to ensure the cooling effect, the overall length of the wavy water-cooling slope 21 should be no less than 400 mm. In one specific embodiment, the overall length of the double-wavy water-cooling slope 21 is 440 mm.

[0044] When the high-temperature molten metal flows through the first wavy slope, the first groove first gathers, stabilizes, and constrains the flow of the high-temperature alloy molten metal. Then, as it flows through the first protrusion, it experiences an initial intense chilling effect under the forced cooling effect of the circulating cooling water on the back. Then, as the metal alloy molten metal with a low solid fraction flows through the second wavy slope, it further gathers and stabilizes the flow with the second groove, and then flows through the second protrusion to generate intense heat exchange. Simultaneously, circulating cooling water is provided on the back of the second protrusion, and the combined effect of the two produces a second forced cooling. Through these two forced cooling and heat exchanges, the alloy is forced to undergo explosive nucleation, forming a special semi-solid slurry consisting of spherical or near-spherical α-Al phases and a residual high-solute liquid phase. This effectively refines and homogenizes the microstructure of the Al-Si alloy while, to a certain extent, suppressing the formation of Fe-rich intermetallic compounds.

[0045] like Figure 1 As shown in FIG2 , the water cooling system of the present invention is a circulating cooling water pipe. The back of the convex portion of the wavy water cooling slope 21 is provided with a mounting groove, and the circulating cooling water pipe is fixed in the mounting groove. The number of cooling water pipes to be installed must match the convex portion of the wavy structure. By providing a recessed mounting groove on the back of the convex portion, the installation stability of the cooling water pipe is ensured, and the cooling water pipe can be in closer contact with the convex portion, thereby better achieving forced heat exchange. In a specific embodiment, as Figure 4 As shown, for the double-wave-shaped water-cooling slope 21 , two groups of cooling water pipes are provided, namely, an upper circulating cooling water pipe 14 and a lower circulating cooling water pipe 20 .

[0046] like Figure 1As shown, the pouring device includes a pouring cup 4 and a fixed plate 2. The fixed plate 2 is located above the wave-shaped water-cooling slope 21. The pouring cup 4 is mounted on the fixed plate 2 via a toggle clamp 1. The pouring cup 4 is a preheated steel pouring cup 4, and a frame with a rectangular opening is provided on the side of the pouring cup 4. After the pouring cup 4 is preheated, the frame with the rectangular opening cooperates with the guide block 3 to achieve correct positioning, and then the pouring cup 4 is fixed to the fixed plate 2 via the toggle clamp 1 to complete the installation.

[0047] As a preference, Figure 1 As shown, the device of the present invention also includes a guide column 8, a guide sleeve 5, and a horizontally movable guide plate 6. The bottom of the guide column 8 is mounted on a fixed seat 11. The upper portion of the guide column 8 is sleeved with a guide sleeve 5 for driving the pouring cup 4 to move up and down. The horizontally movable guide plate 6 is mounted below the fixed plate 2. The side of the horizontally movable guide plate 6 is slidably connected to the guide sleeve 5 via a sliding groove to drive the pouring cup 4 to move horizontally. The guide sleeve 5 is bolted into the sliding groove on the side of the horizontally movable guide plate 6. By adjusting the bolts, the pouring cup 4, the fixed plate 2, and the horizontally movable guide plate 6 can be moved horizontally as a whole. The guide column 8 and the guide sleeve 5 are bolted together. By adjusting the bolts, the pouring cup 4, the fixed plate 2, and the horizontally movable guide plate 6 can be moved up and down as a whole. This design provides the pouring cup 4 with adjustability, thereby ensuring the relative position between the pouring cup 4 and the wave-shaped water-cooling slope 21, suitable for various usage requirements.

[0048] As a preference, Figure 1 and 2 As shown, the collecting device includes a collecting crucible 19, a high-temperature resistant pad 17, a handle 16, and a linear guide 18. The ends of the high-temperature resistant pad 17 are connected to the linear guide 18 for linear motion. The collecting crucible 19 is placed on the high-temperature resistant pad 17. The high-temperature resistant pad 17 is connected to the handle 16 for pulling the high-temperature resistant pad 17 and the collecting crucible 19. The collecting crucible 19 is used to collect semi-solid slurry and is placed on the high-temperature resistant pad 17, aligned with the discharge port of the wavy water-cooled slope 21. The handle 16 is fixed to the side of the high-temperature resistant pad 17 by bolts, and the linear guide 18 is connected to the fixing seat 2 15 by bolts. The collecting device of the present invention can be pulled, which facilitates the removal of materials after collection is completed.

[0049] As a preference, Figure 1 and 2As shown, the device of the present invention also includes an angle adjustment device for adjusting the inclination angle of the wavy water-cooling slope 21. The angle adjustment device includes a plurality of hinge seats, a self-locking cylinder 10, and a push rod 9. The self-locking cylinder 10 is mounted on a fixed seat 11 via a hinge seat. The upper end of the wavy water-cooling slope 21 is connected to the push rod 9 with the self-locking cylinder 10 via a hinge seat 7. The lower end of the wavy water-cooling slope 21 is mounted on a support platform 13 via a hinge seat 3. The support platform 13 is provided on a fixed seat 11. During use, the movement of the push rod 9 is achieved by adjusting the air inlet and outlet of the self-locking cylinder 10, thereby pushing the wavy water-cooling slope 21 to rotate around the bottom hinge seat 3, thereby adjusting the angle between the wavy water-cooling slope 21 and the horizontal plane, thereby controlling the cooling time of the molten metal flowing through the wavy water-cooling slope 21.

[0050] Comparative Example 1.

[0051] The conventional cast A356 alloy, which does not use the wave-shaped semi-solid slurry preparation device of the present invention, is prepared as follows: (1) Weigh 5 kg of A356 ingot raw material and place it in a medium frequency induction heating furnace for melting at a temperature of 715 °C. After melting, keep it in the furnace for 2 minutes. When the molten metal temperature drops to 700 °C, degas and slag treatment are carried out, and then air-cooled to 675 °C to obtain molten metal; (2) After a clear crust appears on the surface of the A356 metal liquid in the crucible to be collected, water quenching is performed.

[0052] Example 2.

[0053] A356 alloy semi-solid ingot is prepared by using the wave-shaped semi-solid slurry preparation device of the present invention, and the preparation method is as follows: (1) Weigh 5 kg of A356 ingot raw material and place it in a medium frequency induction heating furnace for melting at a temperature of 715 °C. After melting, keep it in the furnace for 2 minutes. When the molten metal temperature drops to 700 °C, degas and slag treatment are carried out, and then air-cooled to 675 °C to obtain molten metal; (2) The inclination angle of the wavy water-cooling slope was adjusted to 35° by the push rod and the self-locking cylinder. At the same time, the discharge port of the pouring cup was aligned with the first buffer groove on the wavy water-cooling slope by adjusting the guide sleeve, the horizontal moving guide plate and the guide column. The length of the cooling channel in contact with the molten metal was ensured to be not less than 400 mm. The circulating cooling water flow rates of the upper circulating cooling water pipe and the lower circulating cooling water pipe were adjusted to 40 ml / s and 35 ml / s respectively. The cooling rate of the molten metal after the rapid supercooling induced explosive nucleation treatment was 200 °C / s, and the semi-solid slurry of A356 alloy was obtained. (3) A crucible preheated to 400°C was used to collect the semi-solid slurry of A356 alloy, and then the semi-solid slurry of A356 alloy in the crucible was water quenched after a clear solidified shell appeared on the surface.

[0054] Example 3.

[0055] The only difference between this embodiment and embodiment 2 is that in step (2), the discharge port of the pouring cup is aligned with the second buffer groove on the wavy water-cooling slope surface by adjusting the guide sleeve, the horizontally movable guide plate, and the guide column, ensuring that the length of the cooling channel in contact with the molten metal is not less than 200 mm.

[0056] The microstructures of the semi-solid ingots of A356 alloy obtained in Comparative Example 1 and Examples 2 and 3 are shown in FIG. Figure 5-7 As shown: Figure 5 The morphology of the traditional cast A356 alloy is characterized by a large number of dendrites, and the eutectic Si phase is continuously distributed around the primary α-Al phase in a network structure, which is not conducive to improving the strength and plasticity of the alloy. Figure 6 The microstructure of the semi-solid ingot of A356 alloy obtained by using the wavy semi-solid slurry preparation device of the present invention has the best uniformity. The eutectic Si particles are relatively evenly distributed around the primary α-Al phase in the α-Al matrix with a thin rod-like structure. Figure 7 Although the microstructure shown is prepared using the wavy semi-solid slurry preparation device of the present invention, only one wavy structure is used, which has a poor chilling effect on the A356 alloy liquid. The overall distribution of the microstructure is very uneven, the primary α-Al growth is insufficient, and the high-density eutectic structure is distributed very unevenly around the primary α-Al phase in the form of a huge network, which is not conducive to improving the strength and plasticity of the alloy.

[0057] Example 4.

[0058] A method for preparing a high-strength, lightweight, die-cast aluminum-silicon alloy structural part is as follows: (1) Weigh 5 kg of A356 ingot raw material and place it in a medium frequency induction heating furnace for melting at a temperature of 715 °C. After melting, keep it in the furnace for 2 minutes. When the molten metal temperature drops to 700 °C, degas and slag treatment are carried out, and then air-cooled to 675 °C to obtain molten metal; (2) The inclination angle of the double-wavy water-cooling slope was adjusted to 35° by the push rod and the self-locking cylinder. At the same time, the discharge port of the pouring cup was aligned with the first buffer groove on the surface of the wavy water-cooling slope by adjusting the guide sleeve, the horizontal moving guide plate and the guide column. The length of the cooling channel in contact with the molten metal was ensured to be not less than 400 mm. The circulating cooling water flow rates of the upper circulating cooling water pipe and the lower circulating cooling water pipe were adjusted to 40 ml / s and 35 ml / s respectively. The cooling rate of the molten metal after the rapid supercooling induced explosive nucleation treatment was 200 °C / s, and the semi-solid slurry of A356 alloy was obtained. (3) A356 alloy semi-solid slurry was collected using a crucible preheated to 400 °C and then quickly poured into the press chamber of a horizontal die-casting machine using a ceramic spoon; (4) Set the forming pressure of the horizontal die-casting machine to 125 MPa, the filling speed to 25 mm / s, and the mold temperature to 350 °C. After the die-casting is completed, keep the mold warm for 1.5 minutes, then remove the part and quickly water-quench it to room temperature. (5) The castings were solution treated at 525 °C for 2.5 hours and then artificially aged at 180 °C for 3 hours; (6) The casting was subjected to slow isothermal hot extrusion with an extrusion pressure of 100 MPa, a holding temperature of 300°C, an extrusion time of 15 min, and a holding time of 20 min after the extrusion to obtain a high-strength and high-plasticity die-cast A356 alloy.

[0059] Example 5.

[0060] A method for preparing a high-strength, lightweight, die-cast aluminum-silicon alloy structural part is as follows: (1) Weigh 5 kg of A356 ingot raw material and place it in a medium frequency induction heating furnace for melting at a temperature of 715 °C. After melting, keep it in the furnace for 2 minutes. When the molten metal temperature drops to 700 °C, degas and slag treatment are carried out, and then air-cooled to 675 °C to obtain molten metal; (2) The inclination angle of the double-wavy water-cooling slope was adjusted to 35° by the push rod and the self-locking cylinder. At the same time, the discharge port of the pouring cup was aligned with the first buffer groove on the surface of the wavy water-cooling slope by adjusting the guide sleeve, the horizontal moving guide plate and the guide column. The length of the cooling channel in contact with the molten metal was ensured to be no less than 400 mm. The circulating cooling water flow rates of the upper circulating cooling water pipe and the lower circulating cooling water pipe were adjusted to 40 ml / s and 35 ml / s respectively. The cooling rate of the molten metal after the rapid supercooling induced explosive nucleation treatment was 200 °C / s, and the semi-solid slurry of A356 alloy was obtained. (3) A356 alloy semi-solid slurry was collected in a crucible preheated to 400 °C and then quickly poured into the pressure chamber of a horizontal die-casting machine; (4) Set the injection pressure of the horizontal die-casting machine to 125 MPa, the filling speed to 25 mm / s, and the mold temperature to 350 °C. After the die-casting is completed, keep the mold warm for 1.5 minutes, then remove the part and quickly water-quench it to room temperature. (5) The casting was subjected to slow isothermal hot extrusion with an extrusion pressure of 100 MPa, a holding temperature of 300°C, an extrusion time of 15 min, and a holding time of 20 min after the extrusion to obtain an A356 alloy extruded part; (6) The hot extruded castings were solution treated at 525 °C for 2.5 hours and then artificially aged at 180 °C for 3 hours to obtain high-strength and high-plasticity die-cast A356 alloy.

[0061] The microstructures of the high strength and high plasticity die-cast A356 alloys obtained in Examples 3 and 4 are respectively Figure 8 and Figure 9 : from Figure 8 It can be seen that in the material obtained by isothermal hot extrusion followed by T6 heat treatment, the eutectic Si phase is distributed in the form of particles around the α-Al matrix, but the distribution is not uniform. At the same time, there are larger and more rod-shaped eutectic Si phases. from Figure 9 It can be seen that after T6 heat treatment and isothermal hot extrusion, the eutectic Si particles are dispersed around the α-Al matrix and are more evenly distributed. The eutectic Si particles are spherical or nearly spherical, compared with Figure 8 In terms of spheroidization, the spheroidization effect is better and the size is smaller, which is more conducive to improving the tensile strength and plasticity of the alloy.

[0062] Comparative Example 2.

[0063] The only difference between this comparative example and Example 4 is that step (6) is no longer performed after step (5), that is, isothermal hot extrusion is not performed, and metallographic sampling and mechanical property testing are directly performed.

[0064] Comparative Example 3.

[0065] The only difference between this comparative example and Example 4 is that step (5) and step (6) are no longer performed after step (4), that is, isothermal hot extrusion and T6 heat treatment are not performed, and metallographic sampling and mechanical property testing are directly performed.

[0066] Comparative Example 4.

[0067] A method for preparing die-cast A356 alloy is as follows: (1) Weigh 5 kg of A356 ingot raw material and place it in a medium frequency induction heating furnace for melting at a temperature of 715 °C. After melting, keep it in the furnace for 2 minutes. When the molten metal temperature drops to 700 °C, degas and slag treatment are carried out, and then air-cooled to 675 °C to obtain molten metal; (2) Use a crucible preheated to 400 °C to collect the A356 alloy liquid metal, and then quickly pour it into the pressure chamber of the horizontal die casting machine; (3) Set the injection pressure of the horizontal die-casting machine to 125 MPa, the filling speed to 25 mm / s, and the mold temperature to 350 °C. After the die-casting is completed, keep the mold warm for 1.5 minutes, then remove the part and quickly water-quench it to room temperature. (4) The hot extruded castings were solution treated at 525 °C for 2.5 hours and then artificially aged at 180 °C for 3 hours to obtain high-strength and high-plasticity A356 alloy.

[0068] Comparative Example 5.

[0069] A method for preparing a die-cast aluminum-silicon alloy casting is as follows: (1) Weigh 5 kg of A356 ingot raw material and place it in a medium frequency induction heating furnace for melting at a temperature of 715 °C. After melting, keep it in the furnace for 2 minutes. When the molten metal temperature drops to 700 °C, degas and slag treatment are carried out, and then air-cooled to 675 °C to obtain molten metal; (2) A356 alloy molten metal was collected in a crucible preheated to 400°C and then quickly poured into the pressure chamber of a horizontal die-casting machine; (3) Set the injection pressure of the horizontal die-casting machine to 125 MPa, the filling speed to 25 mm / s, and the mold temperature to 350 °C. After the die-casting is completed, keep the mold warm for 1.5 minutes, then remove the part and quickly water-quench it to room temperature. (5) The casting was subjected to slow isothermal hot extrusion with an extrusion pressure of 100 MPa, a holding temperature of 300°C, an extrusion time of 15 min, and a holding time of 20 min after the extrusion to obtain an A356 alloy extruded part; (6) The hot extruded castings were solution treated at 525 °C for 2.5 hours and then artificially aged at 180 °C for 3 hours to obtain high-strength and high-plasticity A356 alloy.

[0070] The microstructure of the die-cast aluminum-silicon alloy samples prepared in the above comparative examples 2-5 is shown in FIG. Figure 10-13 As shown: from Figure 10It can be seen that the product obtained by semi-solid rheo-die casting + T6 heat treatment without isothermal hot extrusion has obvious spheroidization effect of α-Al phase, and the eutectic Si phase has a rod-like morphology distribution with obvious blunt edges and corners, and is relatively evenly distributed around the primary α-Al. from Figure 11 It can be seen that the product obtained by only semi-solid rheo-die casting without T6 heat treatment and isothermal hot extrusion has an uneven distribution of phases in the microstructure. Some α-Al growth is insufficient and rose-shaped. A large number of eutectic Si phases with needle-like structures aggregate with each other and are distributed disorderly around the α-Al phase, separating the matrix, which is not conducive to improving the high strength and good plasticity of the alloy. from Figure 12 It can be seen that the microstructure of the product obtained by traditional liquid die casting + T6 is that the α-Al phase presents a coarse dendritic morphology, while the eutectic Si phase in the microstructure is still a slender needle-like structure with sharp edges and corners, which seriously splits the alloy matrix. The sharp edges and corners easily cause stress concentration and reduce the mechanical properties of the alloy. from Figure 13 It can be seen that the microstructure of the product obtained by using traditional liquid die casting + hot pressing + T6 is similar to the results of comparative example 4. The α-Al phase appears as coarse columnar dendrites, and the eutectic Si phase around the α-Al phase is relatively thick. Figure 12 The spheroidization effect is good and the overall shape is round rod.

[0071] The tensile strength and elongation of the die-cast aluminum-silicon alloy samples prepared in Examples 4 and 5 and Comparative Examples 2-5 were tested. The test results are shown in Table 1. The stress-strain curve comparison diagram is shown in Table 1. Figure 14 shown.

[0072] Table 1. Test data of aluminum-silicon alloy die castings prepared in Examples and Comparative Examples

[0073] From the data in Table 1 we can see that: By regulating and controlling the semi-solid rheo-die-casting, isothermal hot extrusion, and short-time T6 heat treatment processes, the present invention achieves aluminum-silicon alloy die-cast structural components with a tensile strength greater than 260 MPa and an elongation greater than 15%. Furthermore, it was found that after semi-solid rheo-die-casting, followed by isothermal hot extrusion and short-time T6 heat treatment, the tensile strength of the aluminum-silicon alloy die-cast structural components slightly decreased from 289.7 MPa to 260.1 MPa, but the elongation significantly increased from 15.2% to 21.4%, compared to short-time T6 heat treatment followed by isothermal hot extrusion. This achieves a better balance between the tensile strength and elongation of the die-cast aluminum-silicon alloy. Comparative Example 1 did not undergo isothermal hot extrusion, and Comparative Example 2 did not undergo isothermal hot extrusion and T6 heat treatment, resulting in a low elongation product. Comparative Examples 4 and 5 were both prepared under traditional liquid die-casting conditions, and the resulting tensile strength was significantly reduced, and the product elongation was low.

[0074] Finally, it should be noted that the above specific embodiments are only used to explain in detail the purpose, technical solutions and beneficial effects of the present invention. It should be understood that the above is only a specific implementation method of the present invention and is not used to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the above specific embodiments, ordinary technicians in this field should understand that it is still possible to modify the technical solutions described in the above embodiments, or to replace or improve some or all of the technical features therein. These modifications, equivalent replacements, and improvements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered by the scope of the claims and description of the present invention.

Claims

1. A wave-type semi-solid slurry preparation device, characterized in that: include: A wave-shaped water-cooling slope (21) is used for forced cooling of the metal liquid to form a semi-solid slurry, wherein the slope surface of the wave-shaped water-cooling slope (21) is provided with grooves and protrusions, and the back of the protrusions is provided with a water cooling system; A pouring device is provided above the wave-shaped water-cooling slope (21) and is used to pour the molten metal onto the slope surface of the wave-shaped water-cooling slope (21); A collecting device is provided at the discharge port of the wave-shaped water-cooling slope (21) and is used to collect the semi-solid slurry; The molten metal flows through the grooves of the wave-shaped water-cooling slope (21) to be gathered, and then flows through the convex parts of the wave-shaped water-cooling slope (21) to undergo strong heat exchange, so that the cooling rate of the molten metal reaches 200-300°C / s.

2. The wave-shaped semi-solid slurry preparation device according to claim 1, characterized in that: The wave-shaped water-cooling slope (21) comprises at least two sections of protrusions and two sections of grooves, and the overall length is not less than 400 mm.

3. The wave-shaped semi-solid slurry preparation device according to claim 1, characterized in that: The water cooling system is a circulating cooling water pipe. The convex back side of the wave-shaped water cooling slope (21) is provided with an installation groove, and the circulating cooling water pipe is fixed in the installation groove.

4. The wave-shaped semi-solid slurry preparation device according to claim 1, characterized in that: The pouring device comprises a pouring cup (4) and a fixed plate (2), wherein the fixed plate (2) is arranged above a wave-shaped water-cooling slope (21), and the pouring cup (4) is mounted on the fixed plate (2) via a toggle clamp (1).

5. The wave-shaped semi-solid slurry preparation device according to claim 4, characterized in that: It also includes a guide column (8), a guide sleeve (5) and a horizontally movable guide plate (6), wherein the bottom of the guide column (8) is mounted on a fixed seat (11), the upper part of the guide column (8) is sleeved with a guide sleeve (5) for driving the pouring cup (4) to move up and down, and the horizontally movable guide plate (6) is mounted below the fixed plate (2), and the side of the horizontally movable guide plate (6) is slidably connected to the guide sleeve (5) through a sliding groove for driving the pouring cup (4) to move horizontally.

6. A wave-shaped semi-solid slurry preparation device according to any one of claims 1 to 5, characterized in that: The invention also includes an angle adjustment device for adjusting the inclination angle of the wave-shaped water-cooling slope (21), wherein the angle adjustment device includes a plurality of hinge seats, a self-locking cylinder (10) and a push rod (9), wherein the self-locking cylinder (10) is mounted on a fixed seat (11) through a hinge seat, and the upper end of the wave-shaped water-cooling slope (21) is connected to the push rod (9) with the self-locking cylinder (10) through a hinge seat (7), and the lower end of the wave-shaped water-cooling slope (21) is mounted on a support platform (13) through a hinge seat (3), and the support platform (13) is arranged on a fixed seat (11).

7. A method for preparing a high-strength and lightweight die-cast aluminum-silicon alloy structural part, characterized in that: The following steps are involved: The aluminum-silicon alloy liquid is rapidly supercooled to induce explosive nucleation using the device according to any one of claims 1 to 6 to obtain an aluminum-silicon alloy semi-solid slurry, with a cooling rate of 200-300°C / s; Die-cast aluminum-silicon alloy semi-solid slurry to form die-cast aluminum-silicon alloy castings with medium strength and medium plasticity; Isothermal hot extrusion is performed on die-cast aluminum-silicon alloy castings to obtain die-cast aluminum-silicon alloy structural parts with high strength and medium plasticity; The die-cast aluminum-silicon alloy structural parts are subjected to T6 heat treatment to obtain high-strength, toughness and lightweight die-cast aluminum-silicon alloy structural parts.

8. The method for preparing a high-strength and lightweight die-cast aluminum-silicon alloy structural part according to claim 7, characterized in that: The process parameters of the isothermal hot extrusion are as follows: hot extrusion pressure of 50-200 MPa, extrusion speed of 1-5 mm / s, extrusion time of 5-15 min, holding time of 5-120 min, and isothermal temperature of 200-400°C.

9. The method for preparing a high-strength and lightweight die-cast aluminum-silicon alloy structural part according to claim 8, characterized in that: The T6 heat treatment includes solution treatment and artificial aging treatment; wherein, the solution treatment: the temperature is 400-600°C, and the time is 1.5-3 hours; the artificial aging treatment: the temperature is 100-200°C, and the time is 1.5-4 hours.

10. A high-strength, tough, and lightweight die-cast aluminum-silicon alloy structural part, prepared by the method according to any one of claims 7 to 9.

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