Aluminum / iron double-metal composite material based on micro-textured middle layer and preparation method of aluminum / iron double-metal composite material

Abstract

The invention belongs to the technical field of composite material casting, and relates to an aluminum / iron bimetal composite material based on a micro-textured intermediate layer and a preparation method thereof.The micro-textured intermediate layer is pre-arranged on the surface of an iron base material in advance in an electro-deposition and laser etching composite mode, and in the liquid-solid composite casting process, the micro-textured intermediate layer is pre-arranged on the surface of the iron base material in advance; the middle layer plays a role in isolating direct contact between the liquid aluminum alloy melt and the solid iron base material, and the microstructure on the surface of the middle layer plays a role in inducing stress coordinated distribution. The problem that the interface is easy to crack can be effectively solved through dual control of the interface phase composition and the interface structure of the aluminum / iron double-metal composite material, so that the interface bonding strength of the aluminum / iron double-metal composite material is stably improved.

Description

Technical Field

[0001] The invention relates to the technical field of composite material casting, in particular to an aluminum / iron bimetallic composite material based on a micro-textured intermediate layer and a preparation method thereof. Background Art

[0002] The aluminum / iron bimetallic composite material formed by cooling the liquid aluminum alloy melt on the surface of the iron-based material by the liquid-solid composite casting method not only combines the low density, high thermal conductivity, toughness and good corrosion resistance of aluminum alloy, but also combines the advantages of excellent mechanical properties, high yield strength and good wear resistance of iron-based materials. Therefore, aluminum / iron bimetallic composite materials have become one of the preferred materials for lightweight design of vehicle engines. However, as the engine develops towards high explosive pressure and high load, the problem of insufficient interface bonding strength or easy cracking of aluminum / iron bimetallic composite materials cast by liquid-solid composite casting has been exposed. The reasons are mainly attributed to the following two points: First, the thermal properties of aluminum and iron are quite different, and stress is easily generated at the interface during the composite casting process, leading to cracking; second, aluminum and iron are very easy to react to form hard and brittle aluminum-iron binary metal compounds, which will cause brittle fracture once subjected to external force.

[0003] In order to solve the above problems, a commonly used method is to use hot-dip low-melting-point alloys, such as hot-dip a layer of aluminum or zinc on the surface of the iron substrate to reduce or avoid the contact between the aluminum melt and the iron substrate, thereby reducing the formation of large-area continuous intermetallic compounds at the aluminum-iron interface. The hot-dip method protects the pre-treated iron substrate surface from contamination and oxidation on the one hand, and reduces the temperature difference between the liquid aluminum alloy melt and the solid iron substrate on the other hand, thereby promoting the interface reaction between the aluminum alloy melt and the iron substrate, but has little effect on inhibiting the interface binary aluminum-iron brittle intermetallic compounds. Therefore, although an aluminum / iron bimetallic composite material with a metallurgical bond at the interface is obtained, the problem of easy cracking of the interface during stress is still quite significant. Summary of the invention

[0004] In order to solve the problems existing in the prior art, the main purpose of the present invention is to provide an aluminum / iron bimetallic composite material based on a micro-textured intermediate layer and a preparation method thereof.

[0005] To solve the above technical problems, according to one aspect of the present invention, the present invention provides the following technical solutions: A method for preparing an aluminum / iron bimetallic composite material based on a micro-textured intermediate layer comprises the following steps: S1. Activating the surface of the iron substrate; S2, preparing an intermediate layer on the surface of the iron substrate; S3, performing microtexturing on the surface of the intermediate layer; S4. Liquid-solid composite casting is performed using an aluminum solution and an iron substrate after micro-texturing of the intermediate layer surface to obtain an aluminum / iron bimetallic composite material based on a micro-textured intermediate layer.

[0006] As a preferred embodiment of the method for preparing an aluminum / iron bimetallic composite material based on a micro-textured intermediate layer according to the present invention, in step S1, the activation treatment includes grinding, cleaning, and drying treatment, which specifically includes the following steps: S11. Use sandpaper to polish the surface of the iron substrate to remove surface rust; S12, placing the iron substrate in a NaOH solution for ultrasonic alkaline washing to remove oil stains on the surface of the substrate; S13, washing the iron substrate under running water to remove the residual NaOH solution on the surface; S14, placing the iron substrate in an HCl solution for ultrasonic pickling to further remove the oxide scale on the surface to expose a fresh metal surface; S15, washing the iron substrate under running water to remove residual HCl solution on the surface thereof; S16. Use cold air to dry the surface of the iron substrate for later use.

[0007] As a preferred embodiment of the method for preparing an aluminum / iron bimetallic composite material based on a micro-textured intermediate layer described in the present invention, in which: in the step S1, the iron substrate includes iron and steel, such as ductile iron QT500, carbon steel, etc.

[0008] As a preferred embodiment of the method for preparing an aluminum / iron bimetallic composite material based on a micro-textured intermediate layer according to the present invention, wherein: in step S2, the intermediate layer is prepared by electrodeposition, specifically comprising the following steps: S21, connecting the iron substrate to the negative electrode of the DC power supply, and connecting the positive electrode of the DC power supply to the graphite plate; S22, fixing the iron substrate and the graphite plate at two ends of the container respectively, pouring the prepared intermediate layer plating solution into the container so that the height of the plating solution exceeds the position to be plated of the iron substrate; S23, turning on the DC power supply to start depositing the intermediate layer; S24, turn off the power supply after the target thickness is deposited; S25. Take out the iron substrate from the container, clean it with alcohol ultrasonic wave, and blow dry it with cold air.

[0009] As a preferred embodiment of the method for preparing an aluminum / iron bimetallic composite material based on a micro-textured intermediate layer described in the present invention, in which: in the step S23, the composition of the intermediate layer is not limited, and any metal intermediate layer that can form a uniform and dense metal intermediate layer on the surface of the iron substrate can be used, such as: a copper intermediate layer, a chromium intermediate layer, a nickel intermediate layer, a high entropy alloy intermediate layer, etc.

[0010] As a preferred embodiment of the method for preparing an aluminum / iron bimetallic composite material based on a micro-textured intermediate layer according to the present invention, in step S3, micro-texturing is performed by laser etching, which specifically includes the following steps: S31, placing the iron substrate on the workbench of the laser etching machine, with the side where the intermediate layer is deposited facing the laser gun head; S32, drawing a micro-texture pattern on an operation interface of a laser etching device; S33, setting laser etching parameters; S34, starting the laser equipment system, and the laser generator etches on the surface of the intermediate layer according to the input laser scanning path to obtain an iron substrate with a micro-textured intermediate layer on the surface.

[0011] As a preferred embodiment of the method for preparing an aluminum / iron bimetallic composite material based on a micro-textured intermediate layer described in the present invention, in the step S32, any micro-texture pattern that can increase the contact area between the liquid aluminum alloy melt and the solid iron substrate can be used, such as: pit-shaped pattern, grid-shaped pattern, hexagonal pattern, irregular pattern, etc.

[0012] As a preferred embodiment of the method for preparing an aluminum / iron bimetallic composite material based on a micro-textured intermediate layer according to the present invention, wherein: in the step S4, an iron substrate having a micro-textured intermediate layer on its surface is placed in a mold, and an aluminum melt is cast into the mold for liquid-solid composite casting, specifically comprising the following steps: S41, using a silicon carbon rod furnace to melt aluminum, and degassing the aluminum melt; S42, controlling the melt temperature and keeping it warm to make the melt temperature uniform; S43, placing the iron substrate with the micro-textured intermediate layer on the surface in an insulation box for insulation, and then placing it in a metal mold, and quickly pouring the aluminum melt in the silicon carbon rod furnace into the mold to completely solidify the aluminum melt, thereby completing the liquid-solid composite casting of the aluminum / iron bimetal.

[0013] As a preferred embodiment of the method for preparing an aluminum / iron bimetallic composite material based on a micro-textured intermediate layer described in the present invention, in step S4, the aluminum material is pure aluminum or a cast aluminum alloy.

[0014] To solve the above technical problem, according to another aspect of the present invention, the present invention provides the following technical solution: An aluminum / iron bimetallic composite material based on a micro-textured intermediate layer is prepared by adopting the preparation method of the aluminum / iron bimetallic composite material based on a micro-textured intermediate layer.

[0015] As a preferred solution of the aluminum / iron bimetallic composite material based on a micro-textured intermediate layer described in the present invention, the thickness of the intermediate layer is 20-60 μm.

[0016] The beneficial effects of the present invention are as follows: The present invention proposes an aluminum / iron bimetallic composite material based on a micro-textured intermediate layer and a preparation method thereof. A micro-textured intermediate layer is pre-placed on the surface of an iron substrate in advance by a combination of electrodeposition and laser etching. In the liquid-solid composite casting process, the intermediate layer plays a role in isolating the liquid aluminum alloy melt from direct contact with the solid iron substrate, and the micro-texture on the surface of the intermediate layer plays a role in inducing coordinated stress distribution. The present invention can effectively solve the problem of easy cracking of the interface by dual control of the interface phase composition and interface structure of the aluminum / iron bimetallic composite material, thereby achieving a stable improvement in the interface bonding strength of the aluminum / iron bimetallic composite material. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0018] Figure 1 This is a cross-sectional photograph of an iron substrate having an intermediate layer on the surface in Example 1 of the present invention; Figure 2 This is an interface morphology diagram of the aluminum / iron bimetallic composite material of Example 1 of the present invention.

[0019] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0020] The following will be described clearly and completely in conjunction with the technical solutions in the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] The present invention proposes an aluminum / iron bimetallic composite material based on a micro-textured intermediate layer and a preparation method thereof. After pre-setting the micro-textured intermediate layer, aluminum and iron cannot directly contact each other, and the aluminum-iron binary phase with brittle interface is replaced by other new phases or mixed phases, thereby realizing interface component regulation. In addition, the presence of micro-texture belongs to the category of interface structure design. On the one hand, it increases the contact area between the interface reaction layer and the substrate, and on the other hand, it affects the growth path of the interface reaction layer, reduces the interface stress concentration phenomenon, and realizes artificial intervention of interface stress. Therefore, under the dual guarantee of interface component regulation and interface structure design, the interface bonding strength of aluminum / iron bimetallic is stably improved.

[0022] According to one aspect of the present invention, the present invention provides the following technical solution: A method for preparing an aluminum / iron bimetallic composite material based on a micro-textured intermediate layer comprises the following steps: S1. Activating the surface of the iron substrate; S2, preparing an intermediate layer on the surface of the iron substrate; S3, performing microtexturing on the surface of the intermediate layer; S4. Liquid-solid composite casting is performed using an aluminum solution and an iron substrate after micro-texturing of the intermediate layer surface to obtain an aluminum / iron bimetallic composite material based on a micro-textured intermediate layer.

[0023] Preferably, in step S1, the activation treatment includes grinding, cleaning, and drying, which specifically includes the following steps: S11. Use sandpaper to polish the surface of the iron substrate to remove surface rust; S12, placing the iron substrate in a 5-10wt% NaOH solution, and ultrasonically washing for 3-5 minutes to remove oil stains on the surface of the substrate; S13, rinse the iron substrate under running water for 1-2 minutes to remove the residual NaOH solution on the surface; S14, placing the iron substrate in a 5-10wt% HCl solution, and ultrasonic pickling for 3-5 minutes to further remove the oxide scale on the surface to expose a fresh metal surface; S15, rinsing the iron substrate under running water for 1-2 minutes to remove residual HCl solution on the surface; S16. Use cold air to dry the surface of the iron substrate for later use.

[0024] Preferably, in step S1, the iron substrate includes iron and steel, such as ductile iron QT500, carbon steel, etc. Further preferably, the iron substrate is ductile iron QT500, which has the characteristics of high yield strength, tensile strength, high temperature oxidation resistance, creep resistance, good high temperature strength, etc., and its composition is, by weight percentage, C: 3.6~3.8wt%, Si: 2.5~2.9wt%, Mn<0.6wt%, S<0.025wt%, P<0.08wt%, Mg: 0.03~0.05wt%, RE: 0.03~0.05wt%, and the balance is Fe and unavoidable impurities.

[0025] Preferably, in step S2, the intermediate layer is prepared by electrodeposition, which specifically includes the following steps: S21, connecting the iron substrate to the negative electrode of the DC power supply, and connecting the positive electrode of the DC power supply to the graphite plate; S22, fixing the iron substrate and the graphite plate at two ends of the container respectively, pouring the prepared intermediate layer plating solution into the container so that the height of the plating solution exceeds the position to be plated of the iron substrate; S23, turning on the DC power supply to start depositing the intermediate layer; S24, turn off the power after 10-40 minutes of deposition; S25. Take out the iron substrate from the container, clean it with alcohol ultrasonically for 1 to 5 minutes, and blow dry it with cold air.

[0026] Preferably, in step S2, the composition of the intermediate layer is not limited, and any metal intermediate layer that can form a uniform and dense metal intermediate layer on the surface of the iron substrate can be used, such as a copper intermediate layer, a chromium intermediate layer, a nickel intermediate layer, a high entropy alloy intermediate layer, etc.

[0027] Preferably, in step S3, micro-texturing is performed by laser etching, which specifically includes the following steps: S31, placing the iron substrate on the workbench of the laser etching machine, with the side where the intermediate layer is deposited facing the laser gun head; S32, drawing a micro-texture pattern on an operation interface of a laser etching device; S33, setting the laser spot diameter, laser power and laser scanning speed parameters, the spot is a circular focus spot of 0.1 mm, the laser power is 15-20 W, the scanning speed is 500-1000 mm / s, and the number of processing times for each pattern is 1-3 times; S34, starting the laser equipment system, and the laser generator etches on the surface of the intermediate layer according to the input laser scanning path to obtain an iron substrate with a micro-textured intermediate layer on the surface.

[0028] Preferably, in step S3, any micro-texture pattern that can increase the contact area between the liquid aluminum alloy melt and the solid iron substrate can be used, such as: a pit-shaped pattern, a grid-shaped pattern, a hexagonal pattern, an irregular pattern, etc.

[0029] Preferably, in step S4, the iron substrate having a micro-textured intermediate layer on the surface is placed in a mold, and the aluminum alloy melt is cast into the mold for liquid-solid composite casting, which specifically includes the following steps: S41, using silicon carbon rod furnace to melt aluminum, aluminum melt is degassed at 725 ~ 735 ℃; S42, control the melt temperature to 700~720℃, keep it warm for 10~20min to make the melt temperature uniform; S43. Place the iron substrate with a micro-textured intermediate layer on the surface in an insulation box. After insulation for 5 to 8 minutes, put it into a metal mold at a temperature of 200°C. Quickly pour the aluminum melt in the silicon carbon rod furnace into the mold. Wait until the aluminum melt is completely solidified to complete the liquid-solid composite casting of the aluminum / iron bimetal.

[0030] Preferably, in step S4, the aluminum material is pure aluminum or cast aluminum alloy. Further preferably, the aluminum material is Al-Si alloy ZL702A, which has good fluidity and excellent performance, and its composition is, by weight percentage, Si: 6.0~8.0wt%, Mg: 0.25~0.50wt%, Cu: 1.2~1.8wt%, Mn: 0.1~0.25wt%, Fe≤0.15wt%, and the balance is Al and unavoidable impurities.

[0031] Preferably, in step S4, when the iron substrate is cast iron, the insulation temperature is 250°C; when the iron substrate is steel, the insulation temperature is 300°C.

[0032] According to another aspect of the present invention, the present invention provides the following technical solution: An aluminum / iron bimetallic composite material based on a micro-textured intermediate layer is prepared by using the above-mentioned method for preparing an aluminum / iron bimetallic composite material based on a micro-textured intermediate layer, and the thickness of the intermediate layer is 20-60 μm.

[0033] The technical solution of the present invention is further described below in conjunction with specific embodiments.

[0034] Example 1 In this embodiment, the iron substrate is ductile iron QT500, and its composition is, by weight percentage, C: 3.7wt%, Si: 2.7wt%, Mn: 0.2wt%, S: 0.015wt%, P: 0.05wt%, Mg: 0.04wt%, RE: 0.04wt%, and the balance is Fe and inevitable impurities. The aluminum material is Al-Si alloy ZL702A, and its composition is, by weight percentage, Si: 7.11wt%, Mg: 0.39wt%, Cu: 1.5wt%, Mn: 0.16wt%, Fe: 0.08wt%, and the balance is Al and inevitable impurities. The preparation method of aluminum / iron bimetallic composite material based on micro-textured intermediate layer includes the following steps: S1. Activating the surface of the iron substrate; S11. Use sandpaper to polish the surface of the iron substrate to remove surface rust; S12, placing the iron substrate in a 10wt% NaOH solution and performing ultrasonic alkaline washing for 5 minutes to remove oil stains on the surface of the substrate; S13, rinse the iron substrate under running water for 1 min to remove the residual NaOH solution on the surface; S14, placing the iron substrate in a 10wt% HCl solution and ultrasonically pickling for 5 minutes to further remove the oxide scale on the surface to expose a fresh metal surface; S15, rinsing the iron substrate under running water for 1 min to remove residual HCl solution on the surface; S16. Use cold air to dry the surface of the iron substrate for later use.

[0035] S2, preparing a chromium intermediate layer on the surface of the iron substrate; S21, connecting the iron substrate to the negative electrode of the DC power supply, and connecting the positive electrode of the DC power supply to the graphite plate; S22, fixing the iron substrate and the graphite plate at two ends of the container respectively, pouring the prepared chromium intermediate layer plating solution into the container so that the height of the plating solution exceeds the position to be plated of the iron substrate; S23, turning on the DC power supply to start depositing the chromium intermediate layer; S24, after 40 minutes of deposition, the power supply is turned off to obtain a chromium intermediate layer with a thickness of about 50 μm; S25. Take out the iron substrate from the container, clean it with alcohol ultrasonic for 1 minute, and blow it dry with cold air (the cross-sectional photo of the iron substrate with a chromium intermediate layer on the surface is shown in Figure 2). Figure 1 as shown).

[0036] S3, performing microtexturing on the surface of the chromium intermediate layer; S31, placing the iron substrate on the workbench of the laser etching machine, with the side on which the chromium intermediate layer is deposited facing the laser gun head; S32, drawing a micro-texture pattern on the operation interface of the laser etching device, wherein the center spacing of the grooves of the micro-texture is 450 μm, the groove width is 80 μm, and the depth is 50 μm; S33, setting the laser spot diameter, laser power and laser scanning speed parameters, the spot is a circular focus spot of 0.1 mm, the laser power is 17 W, the laser scanning speed is 700 mm / s, and each groove is processed 3 times; S34, starting the laser equipment system, and the laser generator etches on the surface of the chromium intermediate layer according to the input laser scanning path, so as to obtain an iron substrate with a micro-textured chromium intermediate layer on the surface.

[0037] S4, using an aluminum solution and an iron substrate with a micro-textured chromium intermediate layer surface to perform liquid-solid composite casting to obtain an aluminum / iron bimetallic composite material based on a micro-textured chromium intermediate layer; S41, using a silicon carbon rod furnace to melt aluminum, and degassing the aluminum melt at 730°C; S42, control the melt temperature to 710°C and keep it warm for 10 minutes to make the melt temperature uniform; S43. Place the iron substrate with a micro-textured chromium intermediate layer on the surface in an insulation box. After insulation for 5 minutes, put it into a metal mold at a temperature of 200°C, and quickly pour the aluminum melt in the silicon carbon rod furnace into the mold. The aluminum melt is completely solidified within 60 seconds to complete the liquid-solid composite casting of the aluminum / iron bimetal.

[0038] The interface morphology of aluminum / iron bimetallic composites is shown in Figure 2 As shown in the figure, the left side is the iron substrate and the right side is the aluminum alloy. The narrow strip of the interface is the interface reaction layer formed by the reaction of the chromium intermediate layer with the iron substrate and the aluminum material on both sides. The thickness of the interface reaction layer is 20~25μm. It can be clearly seen from the black dotted circle in the figure that the interface reaction layer containing microtexture is distributed in a discontinuous state, and the reaction layer is bent at the microtexture. In addition, the composition of the interface reaction layer was identified, and the results are shown in Table 1. The three elements Al, Cr and Si are mainly enriched on the side close to the aluminum alloy, and Al and Cr are mainly enriched on the side close to the iron substrate. Combined with the ratio of element content, it can be inferred that Al is formed on the iron side. 5 Cr binary new phase, Al formed near the aluminum side 13 Cr 4 Si 4 Compared with the aluminum / iron bimetal without microtextured chromium interlayer, after the introduction of the "groove-shaped" chromium interlayer, the bimetallic interface is composed of a mixed layer of Al-Cr phase and Al-Cr-Si phase instead of a hard and brittle Al-Fe binary phase (Al 5 Fe 2 、Al 13 Fe 4) and Al-Fe-Si (Al 8 Fe 2 That is, the present invention can achieve dual regulation of interface composition and interface structure, and finally improve the shear strength of the bimetallic interface from 9MPa without micro-textured chromium intermediate layer to 126MPa of the aluminum / iron bimetallic composite material with micro-textured chromium intermediate layer of the present invention.

[0039] Table 1 Main element composition of the interface reaction layer (at%) Compared with the traditional liquid-solid composite casting technology, the present invention innovatively pre-sets a micro-textured intermediate layer on the surface of the iron substrate. On the one hand, the intermediate layer effectively prevents the direct contact between the aluminum melt and the solid iron substrate during the liquid-solid composite process, inhibiting the bimetallic interface Al produced by the traditional technology. 13 Fe 4 、Al 5 Fe 2 On the other hand, the existence of micro-texture can interrupt the continuity of the interface reaction layer and reduce the interface stress concentration. By combining interface component control and interface structure design, the interface cracking problem can be reduced and the interface bonding strength can be steadily improved. This provides a theoretical basis and application foundation for the subsequent replacement of aluminum / iron bimetallic materials in vehicle engines and other products.

[0040] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for preparing an aluminum / iron bimetallic composite material based on a micro-textured intermediate layer, characterized in that: The steps include: S1. Activating the surface of the iron substrate; S2, preparing an intermediate layer on the surface of the iron substrate; S3, performing microtexturing on the surface of the intermediate layer; S4. Liquid-solid composite casting is performed using an aluminum solution and an iron substrate after micro-texturing of the intermediate layer surface to obtain an aluminum / iron bimetallic composite material based on a micro-textured intermediate layer.

2. The method for preparing the aluminum / iron bimetallic composite material based on the micro-textured intermediate layer according to claim 1, characterized in that: In the step S1, the activation treatment includes grinding, cleaning and drying.

3. The method for preparing the aluminum / iron bimetallic composite material based on the micro-textured intermediate layer according to claim 1, characterized in that: In the step S1, the iron substrate is iron or steel.

4. The method for preparing the aluminum / iron bimetallic composite material based on the micro-textured intermediate layer according to claim 1, characterized in that: In the step S2, the intermediate layer is prepared by electrodeposition.

5. The method for preparing the aluminum / iron bimetallic composite material based on the micro-textured intermediate layer according to claim 1, characterized in that: In the step S2, the intermediate layer is a copper intermediate layer, a chromium intermediate layer, a nickel intermediate layer, or a high entropy alloy intermediate layer.

6. The method for preparing the aluminum / iron bimetallic composite material based on the micro-textured intermediate layer according to claim 1, characterized in that: In the step S3, micro-texturing is performed by laser etching.

7. The method for preparing the aluminum / iron bimetallic composite material based on the micro-textured intermediate layer according to claim 6, characterized in that: Microtexturing is performed by laser etching, which specifically includes the following steps: S31, placing the iron substrate on the workbench of the laser etching machine, with the side where the intermediate layer is deposited facing the laser gun head; S32, drawing a micro-texture pattern on an operation interface of a laser etching device; S33, setting laser etching parameters; S34, starting the laser equipment system, and the laser generator etches on the surface of the intermediate layer according to the input laser scanning path to obtain an iron substrate with a micro-textured intermediate layer on the surface.

8. The method for preparing the aluminum / iron bimetallic composite material based on the micro-textured intermediate layer according to claim 7, characterized in that: In the step S32, the micro-texture pattern is a pit-shaped pattern, a grid-shaped pattern, a hexagonal pattern, or an irregular pattern.

9. The method for preparing the aluminum / iron bimetallic composite material based on the micro-textured intermediate layer according to claim 1, characterized in that: In the step S4, the iron substrate having a micro-textured intermediate layer on its surface is placed in a mold, and the aluminum melt is cast into the mold for liquid-solid composite casting.

10. An aluminum / iron bimetallic composite material based on a micro-textured intermediate layer, prepared by the preparation method of an aluminum / iron bimetallic composite material based on a micro-textured intermediate layer according to any one of claims 1 to 9, wherein the thickness of the intermediate layer is 20-60 μm.

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