Preparation method of solid-liquid bimetallic composite material based on self-resistance heating

Abstract

The invention relates to a solid-liquid bimetal composite material preparation method based on self-resistance heating, and belongs to the technical field of solid-liquid bimetal composite casting. In order to solve the problems that in an existing solid-liquid bimetal composite casting technology, a bonding surface is prone to oxidation, and the solid-liquid bimetal composite casting technology is not suitable for large-size solid metal bonding, a pretreated plate-shaped metal base material is fixedly installed on a self-resistance heating device; the sand mold and a plate-shaped metal base material installed on the self-resistance heating device are fixedly assembled together to complete the molding process; and under the inert atmosphere, a self-resistance heating device is started to heat the plate-shaped metal base material, heating is stopped immediately when the temperature is increased to the target temperature, meanwhile, liquid metal obtained through smelting is poured into an inner cavity of the sand mold, cooling is conducted to the room temperature, and the double-metal composite part is obtained. According to the self-resistance heating mode provided by the invention, preheating of the base material can be rapidly and efficiently completed, the oxidation problem of the base material is reduced, and the method is suitable for preparing the solid-liquid bimetal composite material with the plate-shaped base material and the preheating requirement.

Description

Technical Field

[0001] The invention belongs to the technical field of solid-liquid bimetal composite casting, and in particular relates to a method for preparing a solid-liquid bimetal composite material based on self-resistance heating. Background Art

[0002] Bimetallic composite materials are a new type of composite material prepared by a composite process to achieve a firm metallurgical bond between two metal materials with different properties at the composite interface. The metals can maintain independent performance and achieve different improvements in strength, toughness, friction performance, heat resistance, etc. as a whole. Compared with a single metal material, bimetallic composite materials have the excellent properties of both metal materials and a unique "complementary effect", which can improve the current application status of single metal materials due to their individual performance shortcomings. At present, bimetallic composite materials have been used in different fields such as aerospace, automobiles and ships, machinery and chemical industry.

[0003] Solid-liquid bimetallic composite casting technology is mainly a composite material preparation method that pours high-temperature liquid metal onto solid metal, or immerses surface-treated solid metal into high-temperature liquid metal, uses the high temperature of liquid metal to heat the solid metal, and diffuses at the interface to obtain metallurgical bonding. This composite forming process has high requirements for process parameters, but the control difficulty is lower than liquid-liquid composite. Compared with solid-solid composite, such as welding, rolling, extrusion, etc., it greatly shortens the process flow and greatly reduces energy consumption.

[0004] However, the composite material prepared by this composite method has oxidation problems on its bonding surface, and is prone to oxide film and impurity residues, resulting in a decrease in the bonding strength at the composite interface, causing the composite material to have a hidden danger of cracking during subsequent use. In addition, most of the solid metals currently used for the preparation of bimetallic composite materials are rod-shaped and tubular. During the preparation process, the liquid metal is used to reheat the substrate interface to obtain interface bonding, and there is no need to preheat the substrate, but this method is only applicable to bimetallic composites with relatively large liquid-solid volumes, and the solid metal shape is single. For the case where the solid metal volume is large, it is necessary to preheat the substrate, and preheating is usually achieved by heating methods such as resistance furnaces and resistance wires. The energy conversion path is long, the energy utilization rate is low, and the preheating time is long. The longer the preheating time, the thicker the oxide film on the surface of the solid metal, and the worse the interface performance after interface bonding. Limited by this, it is urgent to develop a solid-liquid bimetallic composite preparation technology suitable for solid metal volume. Summary of the invention

[0005] In order to solve the problems in the existing solid-liquid bimetallic composite casting technology that the bonding surface is easily oxidized and is not suitable for large-volume solid metal bonding, the present invention provides a method for preparing a solid-liquid bimetallic composite material based on self-resistance heating.

[0006] The technical solution of the present invention:

[0007] A method for preparing a solid-liquid bimetallic composite material based on self-resistance heating comprises the following steps:

[0008] Step 1: pretreating a plate-shaped metal substrate;

[0009] Step 2: Smelting in an inert atmosphere to obtain liquid metal;

[0010] Step 3: The obtained pre-treated plate-shaped metal substrate is fixedly mounted on the self-resistance heating device, and the sand mold and the plate-shaped metal substrate mounted on the self-resistance heating device are fixedly assembled together to complete the molding process;

[0011] Step 4: In an inert atmosphere, start the self-resistance heating device to heat the plate-shaped metal substrate. When the temperature reaches the target temperature, stop heating immediately. At the same time, pour the liquid metal melted in step 2 into the inner cavity of the sand mold and cool it to room temperature to obtain a bimetallic composite.

[0012] Furthermore, in step one, the pretreatment method for the plate-like metal substrate is to grind the surface of the plate-like solid metal substrate processed into the desired shape to remove surface stains so that the surface reveals a metallic luster, and then ultrasonically clean it to remove residual stains, and then grind and polish the interface to be connected again to further remove the surface oxide film and stains, and finally apply flux and dry it naturally.

[0013] Furthermore, in the pretreatment process of step 1, 80# sandpaper is used for the first grinding, and 80# and 400# sandpaper are used for the second grinding of the connection interface in sequence.

[0014] Furthermore, the reagent used in the ultrasonic cleaning is anhydrous ethanol; the soldering flux is a cesium fluoroaluminate suspension or a potassium fluoroaluminate suspension with a mass fraction of 10-20%.

[0015] Furthermore, the self-resistance heating device in step three includes a power supply, a copper tube, an upper electrode, a lower electrode, a temperature measuring device and a temperature display, and the pretreated plate-shaped metal substrate is fixedly installed between the upper electrode and the lower electrode.

[0016] Furthermore, a heat-resistant sheet is placed between the upper electrode and the plate-shaped metal substrate, and between the lower electrode and the plate-shaped metal substrate. The heat-resistant sheet is a TC4 sheet or a stainless steel sheet.

[0017] Furthermore, after the molding is completed in step three, the internal cavity of the sand mold includes a mold cavity, an overflow groove and a runner. The liquid metal is poured into the mold cavity through the runner. The liquid metal poured onto the surface of the plate-like metal substrate flushes the oxide film on the surface of the plate-like metal substrate, and then flows into the overflow groove until the pouring process is completed.

[0018] Furthermore, in step 4, the power output power of the self-resistance heating device is 15-25 kW, and the current frequency is 15 kHz.

[0019] Furthermore, in step 4, the target temperature of heating the plate-shaped metal substrate is 450-600° C., and the time to reach the target temperature is 30-60 seconds.

[0020] Furthermore, in step 4, the volume ratio of the casting formed in the mold cavity to the volume of the plate-shaped metal substrate is 1 to 3:1.

[0021] Beneficial effects of the present invention:

[0022] The present invention directly passes current through the plate-shaped metal substrate, and uses the "skin effect" of alternating current to achieve a rapid increase in the surface temperature of the substrate by using the self-resistance heating method, while the temperature of the core of the substrate is significantly lower than the surface temperature, and the performance of the substrate itself is less affected during the preheating period. The self-resistance heating method provided by the present invention has a fast heating speed and high energy utilization, and can quickly and efficiently complete the preheating of the substrate, and is suitable for the preparation of solid-liquid bimetallic composite materials with a plate-shaped substrate and preheating requirements.

[0023] The present invention can further reduce the oxidation problem of the substrate during the preheating process by introducing an inert gas into the pouring system and cooperating with the self-resistance heating preheating method. Compared with the traditional vacuum environment to achieve solid-liquid bimetallic composite pouring, the process is simpler and the operation is more convenient. The surface pretreatment of the plate-shaped metal substrate of the present invention is completed by grinding and applying flux, which is simpler to operate than the alkali washing and acid washing used in the traditional substrate treatment.

[0024] The present invention combines a composite casting method with a self-resistance heating method to achieve the complication of the pouring system above the plate-shaped metal substrate, that is, the connector can obtain the required complex structure by changing the shape of the cavity. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A schematic diagram of the structure of the self-resistance heating device provided by the present invention;

[0026] Figure 2 It is a schematic diagram of the structure in which a plate-shaped metal substrate is fixedly installed on a self-resistance heating device in the present invention;

[0027] Figure 3It is a structural schematic diagram of the sand mold and the plate-shaped metal substrate installed on the self-resistance heating device in the present invention, which are fixedly assembled to complete the molding;

[0028] Figure 4 for Figure 3 Schematic diagram of the cross section of the middle AA part;

[0029] Figure 5 for Figure 3 Schematic diagram of the cross section of the middle BB area;

[0030] Figure 6 The microstructure photos and grain orientation diagrams of the interfaces of the 8090 / 2195 bimetallic composite materials prepared in Examples 1 to 3, wherein a is a microstructure photo of the interface of the 8090 / 2195 bimetallic composite material prepared in Example 1 at a substrate heating temperature of 480°C, b is a microstructure photo of the interface of the 8090 / 2195 bimetallic composite material prepared in Example 2 at a substrate heating temperature of 500°C; c is a microstructure photo of the interface of the 8090 / 2195 bimetallic composite material prepared in Example 3 at a substrate heating temperature of 520°C; d is a grain orientation diagram of the interface of the 8090 / 2195 bimetallic composite material prepared in Example 2 at a substrate heating temperature of 500°C;

[0031] Figure 7 This is a comparison chart of the interfacial tensile strength of the 8090 / 2195 bimetallic composite materials prepared at different preheating temperatures in Examples 4 to 7;

[0032] Figure 8 The microstructure photos of the interface of the ZL205A / AlFeSi alloy bimetallic composite material prepared in Example 8 and Example 9, in which a is a microstructure photo of the interface of the ZL205A / AlFeSi alloy bimetallic composite material prepared at a substrate heating temperature of 450°C in Example 8, and b is a microstructure photo of the interface of the ZL205A / AlFeSi alloy bimetallic composite material prepared at a substrate heating temperature of 490°C in Example 9;

[0033] In the figure: 1. power supply, 2. copper tube, 3. upper electrode, 4. substrate, 5. lower electrode, 6. heat barrier, 7. temperature measuring device, 8. temperature display, 9. sand mold, 10. mold cavity, 11. overflow tank, 12. runner. DETAILED DESCRIPTION

[0034] The technical solution of the present invention is further described below in conjunction with the embodiments, but it is not limited thereto. Any modification or equivalent replacement of the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention shall be included in the protection scope of the present invention. The process equipment or devices not specifically noted in the following embodiments are all conventional equipment or devices in the art. If not specifically specified, the raw materials used in the embodiments of the present invention can be obtained commercially; if not specifically specified, the technical means used in the embodiments of the present invention are all conventional means well known to those skilled in the art.

[0035] Example 1

[0036] This embodiment provides a method for preparing a solid-liquid bimetallic composite material based on self-resistance heating, and uses it to prepare a bimetallic composite material of 2195 aluminum-lithium alloy and 8090 aluminum-lithium alloy, wherein the solid metal is 2195 aluminum-lithium alloy and the liquid metal for casting is 8090 aluminum-lithium alloy.

[0037] The method for preparing the solid-liquid bimetallic composite material based on self-resistance heating in this embodiment comprises the following steps:

[0038] Step 1: Pre-treat the plate-shaped metal substrate:

[0039] The surface of the plate-shaped 2195 substrate processed into 230mm×20mm×10mm was polished with 80# sandpaper to remove surface stains and expose the metallic luster on the surface. Then, it was ultrasonically cleaned with anhydrous ethanol to remove residual stains on the surface of the substrate. Subsequently, a grinder with 80# and 400# sandpaper rolls was used to polish the connection interface again to further remove the surface oxide film and stains. Finally, cesium fluoroaluminate flux was applied and naturally dried to obtain a pretreated plate-shaped 2195 substrate. The cesium fluoroaluminate flux used in this embodiment is a cesium fluoroaluminate suspension with anhydrous ethanol as solvent and a mass fraction of 15%.

[0040] Step 2: Melting to obtain liquid metal under inert atmosphere:

[0041] Prepare 8090 aluminum-lithium alloy raw materials according to the national standard composition, melt them in a resistance furnace with high-purity argon gas, obtain liquid metal of 8090 aluminum-lithium alloy, and maintain the melt temperature at 730°C;

[0042] Step 3: The obtained pre-treated plate-shaped metal substrate is fixedly mounted on the self-resistance heating device, and the sand mold and the plate-shaped metal substrate mounted on the self-resistance heating device are fixedly assembled together to complete the molding process;

[0043] The structural schematic diagram of the self-resistance heating device used in this embodiment is as follows Figure 1 and Figure 2As shown, the self-resistance heating device includes a power supply 1, a copper tube 2, an upper electrode 3, a lower electrode 5, a resistor 6, a temperature measuring device 7 and a temperature display 8. The pretreated plate-shaped 2195 substrate 4 is fixedly installed between the upper electrode 3 and the lower electrode 5 by bolting.

[0044] The power source 1 is a high-frequency AC power source, which transmits current to the plate-shaped 2195 substrate 4 through the copper tube 2 and the upper electrode 3, and the temperature of the plate-shaped 2195 substrate 4 is rapidly increased by self-resistance heating to reach the temperature required for preheating the plate-shaped 2195 substrate 4.

[0045] Before the self-resistance heating device is activated, cooling water is passed through the copper tube 2 to ensure that the high temperature generated by the heating of the substrate will not be transferred to the inside of the device to protect normal operation. The presence of cooling water will affect the uniformity of the temperature field of the plate-shaped 2195 substrate 4. Therefore, it is necessary to place a heat-blocking sheet 6 between the upper electrode 3, the lower electrode 5 and the plate-shaped 2195 substrate 4 to supplement heat to the substrate and hinder the transfer of heat to ensure the uniformity of the temperature field of the plate-shaped 2195 substrate 4. The heat-blocking sheet used in this embodiment is a TC4 sheet with a specification of 20mm×10mm×2mm.

[0046] The sand mold 9 is fixedly assembled with the plate-shaped 2195 substrate 4 installed on the self-resistance heating device. The assembly diagram is shown in FIG. Figure 3 The joints between the sand mold 9 and the plate-like 2195 substrate 4 are filled with resin sand or water glass sand to complete the molding process.

[0047] After the molding is completed, the inside of the sand mold is as follows Figure 4 and Figure 5 As shown, the internal cavity formed by molding includes a mold cavity 10, an overflow groove 11 and a runner 12, and the mold cavity 10 is located on the upper part of the plate-like 2195 substrate 4.

[0048] like Figure 4 As shown in the cross-sectional view of the AA portion inside the sand mold, the liquid metal will be poured into the mold cavity 10 through the runner 12. Figure 5 As shown in the cross-sectional view of the BB portion inside the sand mold, the liquid metal poured onto the surface of the plate-like 2195 substrate 4 will first flow into the overflow trough 11. The purpose of designing the overflow trough is to increase the scouring effect of the liquid metal on the oxide film on the surface of the plate-like metal substrate, and at the same time store the liquid metal mixed with gas and oxide film.

[0049] Step 4: Fill the inner cavity of the sand mold obtained by molding in step 3 with high-purity argon gas, adjust the power output of the self-resistance heating device to 20kW, start the self-resistance heating device to heat the plate-like 2195 substrate 4, and stop heating immediately when the temperature of the plate-like 2195 substrate 4 rises to 480°C after 45s. At the same time, pour the 8090 aluminum-lithium alloy liquid metal at 730°C obtained in step 2 into the cavity 10 through the sand mold runner 12, and take it out after cooling to room temperature to obtain the 8090 / 2195 bimetallic composite material. In this embodiment, the volume ratio of the casting formed in the cavity 10 to the volume of the plate-like 2195 substrate 4 is 1.47:1, and the interface size is 170mm×10mm.

[0050] Example 2

[0051] This embodiment provides a method for preparing a solid-liquid bimetallic composite material based on self-resistance heating, and uses it to prepare a bimetallic composite material of 2195 aluminum-lithium alloy and 8090 aluminum-lithium alloy, wherein the solid metal is 2195 aluminum-lithium alloy and the liquid metal for casting is 8090 aluminum-lithium alloy.

[0052] The method for preparing the solid-liquid bimetallic composite material based on self-resistance heating in this embodiment comprises the following steps:

[0053] Step 1: Pre-treat the plate-shaped metal substrate:

[0054] The surface of the plate-shaped 2195 substrate processed into 230mm×20mm×10mm was polished with 80# sandpaper to remove surface stains and expose the metallic luster on the surface. Then, it was ultrasonically cleaned with anhydrous ethanol to remove residual stains on the surface of the substrate. Subsequently, a grinder with 80# and 400# sandpaper rolls was used to polish the connection interface again to further remove the surface oxide film and stains. Finally, cesium fluoroaluminate flux was applied and naturally dried to obtain a pretreated plate-shaped 2195 substrate. The cesium fluoroaluminate flux used in this embodiment is a cesium fluoroaluminate suspension with anhydrous ethanol as solvent and a mass fraction of 15%.

[0055] Step 2: Melting to obtain liquid metal under inert atmosphere:

[0056] Prepare 8090 aluminum-lithium alloy raw materials according to the national standard composition, melt them in a resistance furnace with high-purity argon gas, obtain liquid metal of 8090 aluminum-lithium alloy, and maintain the melt temperature at 730°C;

[0057] Step 3: The obtained pre-treated plate-shaped metal substrate is fixedly mounted on the self-resistance heating device, and the sand mold and the plate-shaped metal substrate mounted on the self-resistance heating device are fixedly assembled together to complete the molding process;

[0058] The structure of the self-resistance heating device, the fixing method of the plate-shaped 2195 substrate 4, and the molding method of fixing and assembling the sand mold 9 and the plate-shaped 2195 substrate 4 installed on the self-resistance heating device are the same as those in Example 1.

[0059] Step 4: Fill the inner cavity of the sand mold obtained by molding in step 3 with high-purity argon gas, adjust the power output of the self-resistance heating device to 20kW, start the self-resistance heating device to heat the plate-like 2195 substrate 4, and stop heating immediately when the temperature of the plate-like 2195 substrate 4 rises to 500°C after 45s. At the same time, pour the 8090 aluminum-lithium alloy liquid metal at 730°C obtained in step 2 into the cavity 10 through the sand mold runner 12, and take it out after cooling to room temperature to obtain the 8090 / 2195 bimetallic composite material. In this embodiment, the volume ratio of the casting formed in the cavity 10 to the volume of the plate-like 2195 substrate 4 is 1.47:1, and the interface size is 170mm×10mm.

[0060] Example 3

[0061] This embodiment provides a method for preparing a solid-liquid bimetallic composite material based on self-resistance heating, and uses it to prepare a bimetallic composite material of 2195 aluminum-lithium alloy and 8090 aluminum-lithium alloy, wherein the solid metal is 2195 aluminum-lithium alloy and the liquid metal for casting is 8090 aluminum-lithium alloy.

[0062] The method for preparing the solid-liquid bimetallic composite material based on self-resistance heating in this embodiment comprises the following steps:

[0063] Step 1: Pre-treat the plate-shaped metal substrate:

[0064] The surface of the plate-shaped 2195 substrate processed into 230mm×20mm×10mm was polished with 80# sandpaper to remove surface stains and expose the metallic luster on the surface. Then, it was ultrasonically cleaned with anhydrous ethanol to remove residual stains on the surface of the substrate. Subsequently, a grinder with 80# and 400# sandpaper rolls was used to polish the connection interface again to further remove the surface oxide film and stains. Finally, cesium fluoroaluminate flux was applied and naturally dried to obtain a pretreated plate-shaped 2195 substrate. The cesium fluoroaluminate flux used in this embodiment is a cesium fluoroaluminate suspension with anhydrous ethanol as solvent and a mass fraction of 15%.

[0065] Step 2: Melting to obtain liquid metal under inert atmosphere:

[0066] Prepare 8090 aluminum-lithium alloy raw materials according to the national standard composition, melt them in a resistance furnace with high-purity argon gas, obtain liquid metal of 8090 aluminum-lithium alloy, and maintain the melt temperature at 730°C;

[0067] Step 3: The obtained pre-treated plate-shaped metal substrate is fixedly mounted on the self-resistance heating device, and the sand mold and the plate-shaped metal substrate mounted on the self-resistance heating device are fixedly assembled together to complete the molding process;

[0068] The structure of the self-resistance heating device, the fixing method of the plate-shaped 2195 substrate 4, and the molding method of fixing and assembling the sand mold 9 and the plate-shaped 2195 substrate 4 installed on the self-resistance heating device are the same as those in Example 1.

[0069] Step 4: Fill the inner cavity of the sand mold obtained by molding in step 3 with high-purity argon gas, adjust the power output of the self-resistance heating device to 20kW, start the self-resistance heating device to heat the plate-like 2195 substrate 4, and stop heating immediately when the temperature of the plate-like 2195 substrate 4 rises to 520°C after 50s. At the same time, pour the 8090 aluminum-lithium alloy liquid metal at 730°C obtained in step 2 into the cavity 10 through the sand mold runner 12, and take it out after cooling to room temperature to obtain the 8090 / 2195 bimetallic composite material. In this embodiment, the volume ratio of the casting formed in the cavity 10 to the volume of the plate-like 2195 substrate 4 is 1.47:1, and the interface size is 170mm×10mm.

[0070] Example 4

[0071] This embodiment provides a method for preparing a solid-liquid bimetallic composite material based on self-resistance heating, and uses it to prepare a bimetallic composite material of 2195 aluminum-lithium alloy and 8090 aluminum-lithium alloy, wherein the solid metal is 2195 aluminum-lithium alloy and the liquid metal for casting is 8090 aluminum-lithium alloy.

[0072] The method for preparing the solid-liquid bimetallic composite material based on self-resistance heating in this embodiment comprises the following steps:

[0073] Step 1: Pre-treat the plate-shaped metal substrate:

[0074] The surface of the plate-shaped 2195 substrate processed into 230mm×50mm×10mm was polished with 80# sandpaper to remove surface stains and expose the metallic luster on the surface. Then, it was ultrasonically cleaned with anhydrous ethanol to remove residual stains on the surface of the substrate. Subsequently, a grinder with 80# and 400# sandpaper rolls was used to polish the connection interface again to further remove the surface oxide film and stains. Finally, cesium fluoroaluminate flux was applied and naturally dried to obtain a pretreated plate-shaped 2195 substrate. The cesium fluoroaluminate flux used in this embodiment is a cesium fluoroaluminate suspension with anhydrous ethanol as solvent and a mass fraction of 15%.

[0075] Step 2: Melting to obtain liquid metal under inert atmosphere:

[0076] Prepare 8090 aluminum-lithium alloy raw materials according to the national standard composition, melt them in a resistance furnace with high-purity argon gas, obtain liquid metal of 8090 aluminum-lithium alloy, and maintain the melt temperature at 730°C;

[0077] Step 3: The obtained pre-treated plate-shaped metal substrate is fixedly mounted on the self-resistance heating device, and the sand mold and the plate-shaped metal substrate mounted on the self-resistance heating device are fixedly assembled together to complete the molding process;

[0078] The heat-resistant sheet used in this embodiment is a TC4 sheet with a specification of 50 mm×10 mm×1 mm.

[0079] The structure of the self-resistance heating device, the fixing method of the plate-shaped 2195 substrate 4, and the molding method of fixing and assembling the sand mold 9 and the plate-shaped 2195 substrate 4 installed on the self-resistance heating device are the same as those in Example 1.

[0080] Step 4: Fill the inner cavity of the sand mold obtained by molding in step 3 with high-purity argon gas, adjust the power output of the self-resistance heating device to 40kW, start the self-resistance heating device to heat the plate-like 2195 substrate 4, and stop heating immediately when the temperature of the plate-like 2195 substrate 4 rises to 450°C after 37s. At the same time, pour the 8090 aluminum-lithium alloy liquid metal at 730°C obtained in step 2 into the cavity 10 through the sand mold runner 12, and take it out after cooling to room temperature to obtain the 8090 / 2195 bimetallic composite material. In this embodiment, the volume ratio of the casting formed in the cavity 10 to the volume of the plate-like 2195 substrate 4 is 2.5:1, and the interface size is 180mm×40mm.

[0081] Example 5

[0082] This embodiment provides a method for preparing a solid-liquid bimetallic composite material based on self-resistance heating, and uses it to prepare a bimetallic composite material of 2195 aluminum-lithium alloy and 8090 aluminum-lithium alloy, wherein the solid metal is 2195 aluminum-lithium alloy and the liquid metal for casting is 8090 aluminum-lithium alloy.

[0083] The method for preparing the solid-liquid bimetallic composite material based on self-resistance heating in this embodiment comprises the following steps:

[0084] Step 1: Pre-treat the plate-shaped metal substrate:

[0085] The surface of the plate-shaped 2195 substrate processed into 230mm×50mm×10mm was polished with 80# sandpaper to remove surface stains and expose the metallic luster on the surface. Then, it was ultrasonically cleaned with anhydrous ethanol to remove residual stains on the surface of the substrate. Subsequently, a grinder with 80# and 400# sandpaper rolls was used to polish the connection interface again to further remove the surface oxide film and stains. Finally, cesium fluoroaluminate flux was applied and naturally dried to obtain a pretreated plate-shaped 2195 substrate. The cesium fluoroaluminate flux used in this embodiment is a cesium fluoroaluminate suspension with anhydrous ethanol as solvent and a mass fraction of 15%.

[0086] Step 2: Melting to obtain liquid metal under inert atmosphere:

[0087] Prepare 8090 aluminum-lithium alloy raw materials according to the national standard composition, melt them in a resistance furnace with high-purity argon gas, obtain liquid metal of 8090 aluminum-lithium alloy, and maintain the melt temperature at 730°C;

[0088] Step 3: The obtained pre-treated plate-shaped metal substrate is fixedly mounted on the self-resistance heating device, and the sand mold and the plate-shaped metal substrate mounted on the self-resistance heating device are fixedly assembled together to complete the molding process;

[0089] The heat-resistant sheet used in this embodiment is a TC4 sheet with a specification of 50 mm×10 mm×1 mm.

[0090] The structure of the self-resistance heating device, the fixing method of the plate-shaped 2195 substrate 4, and the molding method of fixing and assembling the sand mold 9 and the plate-shaped 2195 substrate 4 installed on the self-resistance heating device are the same as those in Example 1.

[0091] Step 4: Fill the inner cavity of the sand mold obtained by molding in step 3 with high-purity argon gas, adjust the power output of the self-resistance heating device to 40kW, start the self-resistance heating device to heat the plate-like 2195 substrate 4, and stop heating immediately when the temperature of the plate-like 2195 substrate 4 rises to 467°C after 38s. At the same time, pour the 8090 aluminum-lithium alloy liquid metal at 730°C obtained in step 2 into the cavity 10 through the sand mold runner 12, and take it out after cooling to room temperature to obtain the 8090 / 2195 bimetallic composite material. In this embodiment, the volume ratio of the casting formed in the cavity 10 to the volume of the plate-like 2195 substrate 4 is 2.5:1, and the interface size is 180mm×40mm.

[0092] Example 6

[0093] This embodiment provides a method for preparing a solid-liquid bimetallic composite material based on self-resistance heating, and uses it to prepare a bimetallic composite material of 2195 aluminum-lithium alloy and 8090 aluminum-lithium alloy, wherein the solid metal is 2195 aluminum-lithium alloy and the liquid metal for casting is 8090 aluminum-lithium alloy.

[0094] The method for preparing the solid-liquid bimetallic composite material based on self-resistance heating in this embodiment comprises the following steps:

[0095] Step 1: Pre-treat the plate-shaped metal substrate:

[0096] The surface of the plate-shaped 2195 substrate processed into 230mm×50mm×10mm was polished with 80# sandpaper to remove surface stains and expose the metallic luster on the surface. Then, it was ultrasonically cleaned with anhydrous ethanol to remove residual stains on the surface of the substrate. Subsequently, a grinder with 80# and 400# sandpaper rolls was used to polish the connection interface again to further remove the surface oxide film and stains. Finally, cesium fluoroaluminate flux was applied and naturally dried to obtain a pretreated plate-shaped 2195 substrate. The cesium fluoroaluminate flux used in this embodiment is a cesium fluoroaluminate suspension with anhydrous ethanol as solvent and a mass fraction of 15%.

[0097] Step 2: Melting to obtain liquid metal under inert atmosphere:

[0098] Prepare 8090 aluminum-lithium alloy raw materials according to the national standard composition, melt them in a resistance furnace with high-purity argon gas, obtain liquid metal of 8090 aluminum-lithium alloy, and maintain the melt temperature at 730°C;

[0099] Step 3: The obtained pre-treated plate-shaped metal substrate is fixedly mounted on the self-resistance heating device, and the sand mold and the plate-shaped metal substrate mounted on the self-resistance heating device are fixedly assembled together to complete the molding process;

[0100] The heat-resistant sheet used in this embodiment is a TC4 sheet with a specification of 50 mm×10 mm×1 mm.

[0101] The structure of the self-resistance heating device, the fixing method of the plate-shaped 2195 substrate 4, and the molding method of fixing and assembling the sand mold 9 and the plate-shaped 2195 substrate 4 installed on the self-resistance heating device are the same as those in Example 1.

[0102] Step 4: Fill the inner cavity of the sand mold obtained by molding in step 3 with high-purity argon gas, adjust the power output of the self-resistance heating device to 40kW, start the self-resistance heating device to heat the plate-like 2195 substrate 4, and stop heating immediately when the temperature of the plate-like 2195 substrate 4 rises to 484°C after 39s. At the same time, pour the 8090 aluminum-lithium alloy liquid metal at 730°C obtained in step 2 into the cavity 10 through the sand mold runner 12, and take it out after cooling to room temperature to obtain the 8090 / 2195 bimetallic composite material. In this embodiment, the volume ratio of the casting formed in the cavity 10 to the volume of the plate-like 2195 substrate 4 is 2.5:1, and the interface size is 180mm×40mm.

[0103] Example 7

[0104] This embodiment provides a method for preparing a solid-liquid bimetallic composite material based on self-resistance heating, and uses it to prepare a bimetallic composite material of 2195 aluminum-lithium alloy and 8090 aluminum-lithium alloy, wherein the solid metal is 2195 aluminum-lithium alloy and the liquid metal for casting is 8090 aluminum-lithium alloy.

[0105] The method for preparing the solid-liquid bimetallic composite material based on self-resistance heating in this embodiment comprises the following steps:

[0106] Step 1: Pre-treat the plate-shaped metal substrate:

[0107] The surface of the plate-shaped 2195 substrate processed into 230mm×50mm×10mm was polished with 80# sandpaper to remove surface stains and expose the metallic luster on the surface. Then, it was ultrasonically cleaned with anhydrous ethanol to remove residual stains on the surface of the substrate. Subsequently, a grinder with 80# and 400# sandpaper rolls was used to polish the connection interface again to further remove the surface oxide film and stains. Finally, cesium fluoroaluminate flux was applied and naturally dried to obtain a pretreated plate-shaped 2195 substrate. The cesium fluoroaluminate flux used in this embodiment is a cesium fluoroaluminate suspension with anhydrous ethanol as solvent and a mass fraction of 15%.

[0108] Step 2: Melting to obtain liquid metal under inert atmosphere:

[0109] Prepare 8090 aluminum-lithium alloy raw materials according to the national standard composition, melt them in a resistance furnace with high-purity argon gas, obtain liquid metal of 8090 aluminum-lithium alloy, and maintain the melt temperature at 730°C;

[0110] Step 3: The obtained pre-treated plate-shaped metal substrate is fixedly mounted on the self-resistance heating device, and the sand mold and the plate-shaped metal substrate mounted on the self-resistance heating device are fixedly assembled together to complete the molding process;

[0111] The heat-resistant sheet used in this embodiment is a TC4 sheet with a specification of 50 mm×10 mm×1 mm.

[0112] The structure of the self-resistance heating device, the fixing method of the plate-shaped 2195 substrate 4, and the molding method of fixing and assembling the sand mold 9 and the plate-shaped 2195 substrate 4 installed on the self-resistance heating device are the same as those in Example 1.

[0113] Step 4: Fill the inner cavity of the sand mold obtained by molding in step 3 with high-purity argon gas, adjust the power output of the self-resistance heating device to 40kW, start the self-resistance heating device to heat the plate-like 2195 substrate 4, and stop heating immediately when the temperature of the plate-like 2195 substrate 4 rises to 500°C after 40s. At the same time, pour the 8090 aluminum-lithium alloy liquid metal at 730°C obtained in step 2 into the cavity 10 through the sand mold runner 12, and take it out after cooling to room temperature to obtain the 8090 / 2195 bimetallic composite material. In this embodiment, the volume ratio of the casting formed in the cavity 10 to the volume of the plate-like 2195 substrate 4 is 2.5:1, and the interface size is 180mm×40mm.

[0114] Example 8

[0115] This embodiment provides a method for preparing a solid-liquid bimetallic composite material based on self-resistance heating, and uses it to prepare a bimetallic composite material of AlFeSi alloy and ZL205A aluminum alloy, wherein the solid metal is AlFeSi alloy and the liquid metal for casting is ZL205A aluminum alloy.

[0116] The method for preparing the solid-liquid bimetallic composite material based on self-resistance heating in this embodiment comprises the following steps:

[0117] Step 1: Pre-treat the plate-shaped metal substrate:

[0118] The surface of the plate-shaped AlFeSi alloy substrate processed into 230mm×50mm×10mm was polished with 80# sandpaper to remove surface stains and expose the metallic luster on the surface, and then it was ultrasonically cleaned with anhydrous ethanol to remove residual stains on the surface of the substrate. Subsequently, the interface to be connected was polished again with a grinder with 80# and 400# sandpaper rolls to further remove the oxide film and stains on the surface. Finally, cesium fluoroaluminate flux was applied and naturally dried to obtain a pretreated plate-shaped AlFeSi alloy substrate; the cesium fluoroaluminate flux used in this embodiment is a cesium fluoroaluminate suspension with anhydrous ethanol as a solvent and a mass fraction of 15%.

[0119] Step 2: Melting to obtain liquid metal under inert atmosphere:

[0120] Prepare ZL205A aluminum alloy raw materials according to the national standard composition, melt them in a resistance furnace with high-purity argon gas, obtain liquid metal of ZL205A aluminum alloy, and maintain the melt temperature at 730°C;

[0121] Step 3: The obtained pre-treated plate-shaped metal substrate is fixedly mounted on the self-resistance heating device, and the sand mold and the plate-shaped metal substrate mounted on the self-resistance heating device are fixedly assembled together to complete the molding process;

[0122] The heat-resistant sheet used in this embodiment is a TC4 sheet with a specification of 50 mm×10 mm×1 mm.

[0123] The structure of the self-resistance heating device, the fixing method of the plate-shaped AlFeSi alloy substrate 4, and the molding method of fixing and assembling the sand mold 9 and the plate-shaped AlFeSi alloy substrate 4 installed on the self-resistance heating device are the same as those in Example 1.

[0124] Step 4: Fill the inner cavity of the sand mold obtained by molding in step 3 with high-purity argon gas, adjust the power output of the self-resistance heating device to 40kW, start the self-resistance heating device to heat the plate-like AlFeSi alloy substrate 4, and stop heating immediately when the temperature of the plate-like AlFeSi alloy substrate 4 rises to 450°C after 35s. At the same time, pour the 730°C ZL205A aluminum alloy liquid metal obtained in step 2 into the cavity 10 through the sand mold runner 12, and take it out after cooling to room temperature to obtain a ZL205A / AlFeSi alloy bimetallic composite material. In this embodiment, the volume ratio of the casting formed in the cavity 10 to the volume of the plate-like AlFeSi alloy substrate 4 is 2.5:1, and the interface size is 180mm×40mm.

[0125] Example 9

[0126] This embodiment provides a method for preparing a solid-liquid bimetallic composite material based on self-resistance heating, and uses it to prepare a bimetallic composite material of AlFeSi alloy and ZL205A aluminum alloy, wherein the solid metal is AlFeSi alloy and the liquid metal for casting is ZL205A aluminum alloy.

[0127] The method for preparing the solid-liquid bimetallic composite material based on self-resistance heating in this embodiment comprises the following steps:

[0128] Step 1: Pre-treat the plate-shaped metal substrate:

[0129] The surface of the plate-shaped AlFeSi alloy substrate processed into 230mm×50mm×10mm was polished with 80# sandpaper to remove surface stains and expose the metallic luster on the surface, and then it was ultrasonically cleaned with anhydrous ethanol to remove residual stains on the surface of the substrate. Subsequently, the interface to be connected was polished again with a grinder with 80# and 400# sandpaper rolls to further remove the oxide film and stains on the surface. Finally, cesium fluoroaluminate flux was applied and naturally dried to obtain a pretreated plate-shaped AlFeSi alloy substrate; the cesium fluoroaluminate flux used in this embodiment is a cesium fluoroaluminate suspension with anhydrous ethanol as a solvent and a mass fraction of 15%.

[0130] Step 2: Melting to obtain liquid metal under inert atmosphere:

[0131] Prepare ZL205A aluminum alloy raw materials according to the national standard composition, melt them in a resistance furnace with high-purity argon gas, obtain liquid metal of ZL205A aluminum alloy, and maintain the melt temperature at 730°C;

[0132] Step 3: The obtained pre-treated plate-shaped metal substrate is fixedly mounted on the self-resistance heating device, and the sand mold and the plate-shaped metal substrate mounted on the self-resistance heating device are fixedly assembled together to complete the molding process;

[0133] The heat-resistant sheet used in this embodiment is a TC4 sheet with a specification of 50 mm×10 mm×1 mm.

[0134] The structure of the self-resistance heating device, the fixing method of the plate-shaped AlFeSi alloy substrate 4, and the molding method of fixing and assembling the sand mold 9 and the plate-shaped AlFeSi alloy substrate 4 installed on the self-resistance heating device are the same as those in Example 1.

[0135] Step 4: Fill the inner cavity of the sand mold obtained by molding in step 3 with high-purity argon gas, adjust the power output of the self-resistance heating device to 40kW, start the self-resistance heating device to heat the plate-like AlFeSi alloy substrate 4, and stop heating immediately when the temperature of the plate-like AlFeSi alloy substrate 4 rises to 490°C after 40s. At the same time, pour the 730°C ZL205A aluminum alloy liquid metal obtained in step 2 into the cavity 10 through the sand mold runner 12, and take it out after cooling to room temperature to obtain a ZL205A / AlFeSi alloy bimetallic composite material. In this embodiment, the volume ratio of the casting formed in the cavity 10 to the volume of the plate-like AlFeSi alloy substrate 4 is 2.5:1, and the interface size is 180mm×40mm.

[0136] Example 10

[0137] This embodiment provides a method for preparing a solid-liquid bimetallic composite material based on self-resistance heating, and uses it to prepare a bimetallic composite material of AlFeSi alloy and ZL205A aluminum alloy, wherein the solid metal is AlFeSi alloy and the liquid metal for casting is ZL205A aluminum alloy.

[0138] The method for preparing the solid-liquid bimetallic composite material based on self-resistance heating in this embodiment comprises the following steps:

[0139] Step 1: Pre-treat the plate-shaped metal substrate:

[0140] The surface of the plate-shaped AlFeSi alloy substrate processed into 230mm×20mm×10mm was polished with 80# sandpaper to remove surface stains and expose the metallic luster on the surface, and then it was ultrasonically cleaned with anhydrous ethanol to remove residual stains on the surface of the substrate. Subsequently, the interface to be connected was polished again with a grinder with 80# and 400# sandpaper rolls to further remove the oxide film and stains on the surface. Finally, cesium fluoroaluminate flux was applied and naturally dried to obtain a pretreated plate-shaped AlFeSi alloy substrate; the cesium fluoroaluminate flux used in this embodiment is a cesium fluoroaluminate suspension with anhydrous ethanol as a solvent and a mass fraction of 15%.

[0141] Step 2: Melting to obtain liquid metal under inert atmosphere:

[0142] Prepare ZL205A aluminum alloy raw materials according to the national standard composition, melt them in a resistance furnace with high-purity argon gas, obtain liquid metal of ZL205A aluminum alloy, and maintain the melt temperature at 720°C;

[0143] Step 3: The obtained pre-treated plate-shaped metal substrate is fixedly mounted on the self-resistance heating device, and the sand mold and the plate-shaped metal substrate mounted on the self-resistance heating device are fixedly assembled together to complete the molding process;

[0144] The heat-resistant sheet used in this embodiment is a TC4 sheet with a specification of 20 mm×10 mm×2 mm.

[0145] The structure of the self-resistance heating device, the fixing method of the plate-shaped AlFeSi alloy substrate 4, and the molding method of fixing and assembling the sand mold 9 and the plate-shaped AlFeSi alloy substrate 4 installed on the self-resistance heating device are the same as those in Example 1.

[0146] Step 4: Fill the inner cavity of the sand mold obtained by completing the molding in step 3 with high-purity argon gas, adjust the power output of the self-resistance heating device to 20kW, start the self-resistance heating device to heat the plate-like AlFeSi alloy substrate 4, and stop heating immediately when the temperature of the plate-like AlFeSi alloy substrate 4 rises to 600°C after 60s. At the same time, pour the 720°C ZL205A aluminum alloy liquid metal obtained in step 2 into the cavity 10 through the sand mold runner 12, and take it out after cooling to room temperature to obtain a ZL205A / AlFeSi alloy bimetallic composite material. In this embodiment, the volume ratio of the casting formed in the cavity 10 to the volume of the plate-like AlFeSi alloy substrate 4 is 2.5:1, and the interface size is 180mm×40mm.

[0147] Embodiment 11

[0148] This embodiment provides a method for preparing a solid-liquid bimetallic composite material based on self-resistance heating, and uses it to prepare a bimetallic composite material of AlFeSi alloy and 8090 aluminum-lithium alloy, wherein the solid metal is AlFeSi alloy and the liquid metal for casting is 8090 aluminum-lithium alloy.

[0149] The method for preparing the solid-liquid bimetallic composite material based on self-resistance heating in this embodiment comprises the following steps:

[0150] Step 1: Pre-treat the plate-shaped metal substrate:

[0151] The surface of the plate-shaped AlFeSi alloy substrate processed into 230mm×20mm×10mm was polished with 80# sandpaper to remove surface stains and expose the metallic luster on the surface, and then it was ultrasonically cleaned with anhydrous ethanol to remove residual stains on the surface of the substrate. Subsequently, the interface to be connected was polished again with a grinder with 80# and 400# sandpaper rolls to further remove the oxide film and stains on the surface. Finally, cesium fluoroaluminate flux was applied and naturally dried to obtain a pretreated plate-shaped AlFeSi alloy substrate; the cesium fluoroaluminate flux used in this embodiment is a cesium fluoroaluminate suspension with anhydrous ethanol as a solvent and a mass fraction of 15%.

[0152] Step 2: Melting to obtain liquid metal under inert atmosphere:

[0153] 8090 aluminum-lithium alloy is prepared according to the national standard composition, and is melted in a resistance furnace with high-purity argon gas to obtain liquid metal of 8090 aluminum-lithium alloy, and the melt temperature is maintained at 720°C;

[0154] Step 3: The obtained pre-treated plate-shaped metal substrate is fixedly mounted on the self-resistance heating device, and the sand mold and the plate-shaped metal substrate mounted on the self-resistance heating device are fixedly assembled together to complete the molding process;

[0155] The heat-resistant sheet used in this embodiment is a TC4 sheet with a specification of 20 mm×10 mm×2 mm.

[0156] The structure of the self-resistance heating device, the fixing method of the plate-shaped AlFeSi alloy substrate 4, and the molding method of fixing and assembling the sand mold 9 and the plate-shaped AlFeSi alloy substrate 4 installed on the self-resistance heating device are the same as those in Example 1.

[0157] Step 4: Fill the inner cavity of the sand mold obtained by molding in step 3 with high-purity argon gas, adjust the power output of the self-resistance heating device to 40kW, start the self-resistance heating device to heat the plate-like AlFeSi alloy substrate 4, and stop heating immediately when the temperature of the plate-like AlFeSi alloy substrate 4 rises to 480°C after 38s. At the same time, pour the 8090 aluminum-lithium alloy liquid metal at 720°C obtained in step 2 into the cavity 10 through the sand mold runner 12, and take it out after cooling to room temperature to obtain the 8090 / AlFeSi alloy bimetallic composite material. In this embodiment, the volume ratio of the casting formed in the cavity 10 to the volume of the plate-like AlFeSi alloy substrate 4 is 1.47:1, and the interface size is 180mm×10mm.

[0158] Example 12

[0159] This embodiment provides a method for preparing a solid-liquid bimetallic composite material based on self-resistance heating, and uses it to prepare a bimetallic composite material of pure aluminum and ZL205A aluminum alloy, wherein the solid metal is pure aluminum and the liquid metal for casting is ZL205A aluminum alloy.

[0160] The method for preparing the solid-liquid bimetallic composite material based on self-resistance heating in this embodiment comprises the following steps:

[0161] Step 1: Pre-treat the plate-shaped metal substrate:

[0162] The surface of the plate-shaped pure aluminum substrate processed into 230mm×50mm×10mm was polished with 80# sandpaper to remove surface stains and expose the metallic luster on the surface, and then it was ultrasonically cleaned with anhydrous ethanol to remove residual stains on the surface of the substrate. Subsequently, the interface to be connected was polished again with a grinder with 80# and 400# sandpaper rolls to further remove the oxide film and stains on the surface, and finally cesium fluoroaluminate flux was applied and naturally dried to obtain a pretreated plate-shaped pure aluminum substrate; the cesium fluoroaluminate flux used in this embodiment is a cesium fluoroaluminate suspension with anhydrous ethanol as a solvent and a mass fraction of 15%.

[0163] Step 2: Melting to obtain liquid metal under inert atmosphere:

[0164] Prepare ZL205A aluminum alloy raw materials according to the national standard composition, melt them in a resistance furnace with high-purity argon gas, obtain liquid metal of ZL205A aluminum alloy, and maintain the melt temperature at 730°C;

[0165] Step 3: The obtained pre-treated plate-shaped metal substrate is fixedly mounted on the self-resistance heating device, and the sand mold and the plate-shaped metal substrate mounted on the self-resistance heating device are fixedly assembled together to complete the molding process;

[0166] The heat-resistant sheet used in this embodiment is a TC4 sheet with a specification of 50 mm×10 mm×1 mm.

[0167] The structure of the self-resistance heating device, the fixing method of the plate-shaped pure aluminum substrate 4, and the molding method of fixing and assembling the sand mold 9 and the plate-shaped pure aluminum substrate 4 installed on the self-resistance heating device are the same as those in Example 1.

[0168] Step 4: Fill the inner cavity of the sand mold obtained by molding in step 3 with high-purity argon gas, adjust the power output of the self-resistance heating device to 40kW, start the self-resistance heating device to heat the plate-like pure aluminum alloy substrate 4, and stop heating immediately when the temperature of the plate-like pure aluminum alloy substrate 4 rises to 500°C after 40s. At the same time, pour the 730°C ZL205A aluminum alloy liquid metal obtained in step 2 into the cavity 10 through the sand mold runner 12, and take it out after cooling to room temperature to obtain a ZL205A / pure aluminum bimetallic composite material. In this embodiment, the volume ratio of the casting formed in the cavity 10 to the volume of the plate-like pure aluminum alloy substrate 4 is 2.5:1, and the interface size is 180mm×10mm.

[0169] Figure 6 The microstructure photos and grain orientation diagrams of the interfaces of the 8090 / 2195 bimetallic composite materials prepared in Examples 1 to 3 show that, from the microstructures of the interfaces of the 8090 / 2195 bimetallic composite materials in a, b, and c, it can be seen that the 8090 matrix and the 2195 matrix achieve good metallurgical bonding and there is no residual oxide film, which indicates that the coordinated use of the self-resistance heating process and the cesium fluorochlorate reagent can effectively remove the oxide film on the surface of the alloy and promote the metallurgical bonding between the two. From the grain orientation of the interface of the 8090 / 2195 bimetallic composite material in d, it can be seen that the structure on one side of the solid substrate has partially recrystallized under the influence of the liquid metal, and there is a continuous transition between the two, which once again proves that the two have achieved good metallurgical bonding.

[0170] Figure 7This is a comparison chart of the interface tensile strength of 8090 / 2195 bimetallic composite materials prepared at different preheating temperatures in Examples 4 to 7. It can be seen from the figure that when the preheating temperature of the 2195 substrate is 450°C, the interface tensile strength is 115MPa, and the tensile strength of the interface increases with the increase of the preheating temperature. When the preheating temperature of the solid substrate is 467°C, the tensile strength of the interface is increased to 161MPa. When the temperature continues to rise, the interface strength shows a gradually decreasing trend, but the tensile strength also exceeds 150MPa. The strength of the cast 8090 substrate is 208MPa, and the tensile strength of the interface exceeds 70% of the substrate strength.

[0171] Figure 8 The microstructure photographs of the interface of the ZL205A / AlFeSi alloy bimetallic composite material prepared in Example 8 and Example 9 show obvious differences in microstructure due to element differences in the two alloys, but show a good transition zone in the interface area with a thickness of more than 100 microns, achieving good metallurgical bonding, indicating that preheating of the substrate by self-resistance heating can reduce the generation of oxide film and reduce the hindrance of the oxide film to interface bonding.

Claims

1. A method for preparing a solid-liquid bimetallic composite material based on self-resistance heating, characterized in that: The following steps are involved: Step 1: pretreating a plate-shaped metal substrate; Step 2: Smelting in an inert atmosphere to obtain liquid metal; Step 3: The obtained pre-treated plate-shaped metal substrate is fixedly mounted on the self-resistance heating device, and the sand mold and the plate-shaped metal substrate mounted on the self-resistance heating device are fixedly assembled together to complete the molding process; Step 4: In an inert atmosphere, start the self-resistance heating device to heat the plate-shaped metal substrate. When the temperature reaches the target temperature, stop heating immediately. At the same time, pour the liquid metal melted in step 2 into the inner cavity of the sand mold and cool it to room temperature to obtain a bimetallic composite.

2. A method for preparing a solid-liquid bimetallic composite material based on self-resistance heating according to claim 1, characterized in that: Step 1: The pretreatment method for the plate-like metal substrate is to grind the surface of the plate-like solid metal substrate processed into the desired shape to remove surface stains and expose the metallic luster on the surface, and then ultrasonically clean it to remove residual stains, and then grind and polish the interface to be connected again to further remove the surface oxide film and stains, and finally apply flux and dry it naturally.

3. A method for preparing a solid-liquid bimetallic composite material based on self-resistance heating according to claim 2, characterized in that: During the pretreatment process of step 1, use 80# sandpaper for the first polishing, and use 80# and 400# sandpaper to polish the connection interface again.

4. The method for preparing a solid-liquid bimetallic composite material based on self-resistance heating according to claim 3, characterized in that: The reagent used in the ultrasonic cleaning is anhydrous ethanol; the soldering flux is a cesium fluoroaluminate suspension or a potassium fluoroaluminate suspension with a mass fraction of 10-20%.

5. A method for preparing a solid-liquid bimetallic composite material based on self-resistance heating according to any one of claims 1 to 4, characterized in that: Step 3: The self-resistance heating device includes a power supply, a copper tube, an upper electrode, a lower electrode, a temperature measuring device and a temperature display. The pretreated plate-shaped metal substrate is fixedly installed between the upper electrode and the lower electrode.

6. The method for preparing a solid-liquid bimetallic composite material based on self-resistance heating according to claim 5, characterized in that: A heat-resistant sheet is placed between the upper electrode and the plate-shaped metal substrate, and between the lower electrode and the plate-shaped metal substrate. The heat-resistant sheet is a TC4 sheet or a stainless steel sheet.

7. A method for preparing a solid-liquid bimetallic composite material based on self-resistance heating according to claim 6, characterized in that: After the molding is completed in step three, the internal cavity of the sand mold includes a mold cavity, an overflow trough and a runner. The liquid metal is poured into the mold cavity through the runner. The liquid metal poured onto the surface of the plate-like metal substrate flushes the oxide film on the surface of the plate-like metal substrate, and then flows into the overflow trough until the pouring process is completed.

8. A method for preparing a solid-liquid bimetallic composite material based on self-resistance heating according to claim 7, characterized in that: In step 4, the power output power of the self-resistance heating device is 15-25 kW, and the current frequency is 15 kHz.

9. A method for preparing a solid-liquid bimetallic composite material based on self-resistance heating according to claim 8, characterized in that: In step 4, the target temperature of heating the plate-shaped metal substrate is 450-600° C., and the time to reach the target temperature is 30-60 seconds.

10. A method for preparing a solid-liquid bimetallic composite material based on self-resistance heating according to claim 9, characterized in that: In step 4, the volume ratio of the casting formed in the cavity to the volume ratio of the plate-shaped metal substrate is 1 to 3:1.

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