Ferro-aluminum composite material interface stress treatment method and ferro-aluminum composite material

Abstract

The invention belongs to the technical field of metallurgy, and particularly relates to an aluminum-iron composite material interface stress treatment method which comprises the following steps: S1, activating the surface of an iron base material; s2, a first aluminum material is adopted to conduct hot dipping on the iron base material, a second aluminum material is adopted to conduct casting on the iron base material subjected to hot dipping, the aluminum-iron composite material is obtained, the first aluminum material is a molten aluminum material with the temperature ranging from 770 DEG C to 790 DEG C, and the second aluminum material is a molten aluminum material with the temperature ranging from 700 DEG C to 720 DEG C; s3, the aluminum-iron composite material is heated to 280 DEG C to 320 DEG C at the heating rate of 3 DEG C / min to 5 DEG C / min, and heat preservation is conducted for 2.5 h to 3.5 h; according to the method, the aluminum-iron composite material obtained through casting is subjected to heat treatment at a certain temperature for a certain time, so that the effect of reducing the interface stress between double metals of the aluminum-iron composite material is achieved, the aluminum side stress in liquid-solid composite aluminum / iron double metals is weakened, the metallurgical bonding integrity of the aluminum / iron double metal interface can be guaranteed, and the service life of the aluminum-iron composite material is prolonged. And the shearing strength of the aluminum / iron bimetal is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of metallurgy, and in particular relates to an interface stress treatment method for an aluminum-iron composite material and an aluminum-iron composite material. Background Art

[0002] With the increasing demand for energy conservation and emission reduction, lightweighting of key automotive components (engines) has become a key research focus. Using the aluminum / iron liquid-solid composite casting method, a reaction layer will be formed between aluminum and iron, resulting in a metallurgical bond, thereby combining the low density, lightweight, and corrosion resistance of aluminum alloys with the excellent strength, wear resistance, excellent vibration damping, and yield strength of cast iron materials.

[0003] The harsh operating environment of automobile engines, with high pressure and high heat, places high demands on the performance of aluminum / iron bimetallic materials. However, cracking defects may occur at the bimetallic interface. This is because the intermetallic compound generated at the interface by the metallurgical bonding of aluminum and iron is a hard and brittle phase. On the other hand, it is due to the internal stress caused by the difference in thermal expansion coefficients of aluminum and iron. These factors can lead to cracking defects at the aluminum-iron bonding interface, which is not conducive to the life of the engine in harsh environments.

[0004] In response to these factors, the conventional method for aluminum / iron bimetallic bonding is to suppress cracking by reducing unfavorable phases and adding an iron matrix intermediate layer, such as using metal mold casting to reduce element diffusion by accelerating cooling; and promoting metallurgical reactions, changing the hard and brittle phase composition, and improving interface stress by galvanizing and copper plating the iron matrix surface.

[0005] The use of a metal mold casting method for liquid-solid aluminum-iron composite casting can accelerate the solidification and cooling of the molten aluminum, thereby slowing the formation of unfavorable phases at the aluminum-iron interface. However, excessive cooling at certain angles can increase the stress at the aluminum-iron interface, leading to cracking. While introducing an intermediate layer on the surface of the iron matrix improves the metallurgical bond between the aluminum and iron, it is less effective in reducing interfacial stress. Summary of the Invention

[0006] To solve the above technical problems, the present invention provides a method for treating interfacial stress of an aluminum-iron composite material, comprising the following steps: S1, activating the surface of an iron substrate; S2, hot-dip the iron substrate with a first aluminum material, and casting the hot-dip iron substrate with a second aluminum material to obtain the aluminum-iron composite material, wherein the first aluminum material is a molten aluminum material at a temperature of 770-790°C, and the second aluminum material is a molten aluminum material at a temperature of 700-720°C; S3, heating the aluminum-iron composite material to 280-320°C at a heating rate of 3-5°C / min and keeping it warm for 2.5-3.5 hours.

[0007] Wherein, in step S1, the activation treatment includes: grinding, alkali washing, and acid washing.

[0008] Wherein, in the step S1, the iron substrate is iron or steel; in the step S2, the first aluminum material and the second aluminum material are aluminum or aluminum alloy.

[0009] Wherein, before step S2, the step further includes: preheating the iron substrate.

[0010] The preheating treatment is to keep the iron substrate at a temperature of 500-600°C for 2-3 minutes, so that the temperature of the iron substrate is raised to 340-360°C.

[0011] Furthermore, the iron substrate is heated to any one of 340, 345, 350, 355, and 360°C, or a range between the two; the first aluminum material is a molten aluminum material having a temperature of any one of 770, 775, 780, 785, and 790°C, or a range between the two; and the second aluminum material is a molten aluminum material having a temperature of 700, 705, 710, 715, and 720°C.

[0012] Wherein, the step S3 further includes: S31, heating the aluminum-iron composite material to 280-320°C at a heating rate of 3-5°C / min, and keeping the temperature for 2.5-3.5h; S32, furnace cooling the aluminum-iron composite material.

[0013] Furthermore, the heating rate is any one of 3°C / min, 4°C / min, 5°C / min or a range between the two, and the holding time is any one of 2.5h, 3h, 3.5h or a range between the two; S32, furnace cooling the aluminum-iron composite material.

[0014] The aluminum-iron composite material includes an aluminum coating, the aluminum coating includes a metallurgical reaction layer and a hot-dip melt layer, the metallurgical reaction layer includes Al5Fe2, Al 13 Fe4, the thickness of the metallurgical reaction layer is 4-6 μm, and the thickness of the aluminum coating is 10-14 μm.

[0015] In order to solve the above technical problems, the present invention also provides an aluminum-iron composite material, which is prepared by the above-mentioned aluminum-iron composite material interface stress treatment method.

[0016] The present invention achieves the effect of reducing the interface stress between the aluminum-iron composite material bimetal by controlling the temperature of the iron substrate during hot dipping and performing a heat treatment at a certain temperature and time on the aluminum-iron composite material obtained by casting. On the one hand, the aluminum side stress in the liquid-solid composite aluminum / iron bimetal is weakened, which can ensure the metallurgical bonding integrity of the aluminum / iron bimetal interface and improve the shear strength of the aluminum / iron bimetal; on the other hand, after the residual stress of the aluminum / iron bimetal is released, the original aluminum / iron bimetal casting sample can be processed more freely and with more options, and the integrity of the aluminum / iron bimetal interface is guaranteed after processing. 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 following briefly introduces the drawings required for use in the embodiments or the description of the prior art. 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 any creative work.

[0018] Figure 1 This is a microscopic image of the aluminum-iron composite material after heat treatment in Example 1, Comparative Example 4, and Comparative Example 5 of the present application; Figure 2 : This is the XRD stress diagram of the aluminum-iron composite material after heat treatment in Example 1 of the present application; Figure 3 This is a microscopic image of the aluminum-iron composite material in Comparative Example 1 of the present application; Figure 4 This is the XRD stress diagram of the aluminum-iron composite material in Comparative Example 1 of this application; Figure 5 The actual image and microscopic image of the aluminum-iron composite material after cutting in Comparative Example 1 of this application; Figure 6 This is a microscopic image of the aluminum-iron composite material in Comparative Examples 2 and 3 of the present application; Figure 7 These are microscopic images of the aluminum-iron composite materials that were not heat-treated in Comparative Examples 1, 2, and 3 of the present application.

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

[0020] The following will be a clear and complete description of the technical solutions in the embodiments. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0021] This invention proposes a method for reducing residual internal stress at the interface of aluminum / iron bimetallic composite materials, overcoming the problem of easy cracking at the interface of aluminum / iron bimetallic composite materials in existing technologies. By controlling the hot-dip temperature of the iron substrate and slowly heating, maintaining the temperature, and then slowly cooling it, the internal stress at the interface of the bimetallic material is reduced, effectively solving the problem of easy cracking at the interface and thus achieving stable bonding at the aluminum / iron bimetallic composite interface. The specific steps are as follows: S1. Activate the surface of the iron substrate; In the embodiments of this application, the iron substrate is ductile iron QT500, which has high tensile strength, yield strength, and elastic modulus. Its composition is C: 3.6wt%-3.8wt%, Si: 2.5wt%-2.9wt%, Mn <0.6wt%, S <0.025wt%, P <0.08wt%, Mg: 0.03wt%-0.05wt%, RE: 0.03wt%-0.05wt%, and the balance is Fe and unavoidable impurities.

[0022] In an embodiment of the present application, the steps of activating the surface of the iron substrate are as follows: the surface of the iron substrate is polished to 1000 mesh with sandpaper to ensure that the surface is smooth and flat; the iron substrate is ultrasonically alkaline washed in a 10wt% NaOH solution for 5 minutes to remove oil stains on the surface of the substrate, and then the residual alkaline solution on the surface of the substrate is rinsed with running water; the iron substrate is placed in a 10wt% HCl solution and ultrasonically pickled for 5 minutes to further remove rust on the surface; the iron substrate is placed in alcohol, ultrasonically cleaned for 10 seconds, and then blown dry to prevent rust.

[0023] S2. hot-dip the iron substrate with a first aluminum material, and cast the hot-dip iron substrate with a second aluminum material to obtain the aluminum-iron composite material, wherein the first aluminum material is a molten aluminum material at a temperature of 770-790° C., and the second aluminum material is a molten aluminum material at a temperature of 700-720° C.; In the embodiments of the present application, step S2 adopts the following processing method: two parts of aluminum alloy are melted in a silicon carbide rod furnace, the aluminum alloy is melted at 730°C, the molten aluminum alloy is degassed and temperature adjusted at 730°C using hexachloroethane, one part of the aluminum alloy is selected and the temperature is adjusted to 700-720°C as a casting melt, the temperature is stabilized at 710°C for 20 minutes, the metal mold and other tools that will come into contact with the melt are coated with boron nitride, the mold is preheated in an electric constant temperature blower dryer at 200°C, and the other part of the aluminum alloy is temperature adjusted to 770-790°C for use as a hot dip melt, and the temperature is stabilized at 780°C for 20 minutes.

[0024] In the embodiment of the present application, the aluminum alloy is selected as Al-Si alloy ZL702A, which has good fluidity and excellent performance. The composition of the Al-Si alloy ZL702A is as follows: Si: 6.0wt%-8.0wt%, Mg: 0.25wt%-0.50wt%, Cu: 1.2wt%-1.8wt%, Mn: 0.1wt%-0.25wt%, Ti: 0.1wt%-0.2wt%, Fe≤0.15wt%, Sr: 0.01wt%-0.06wt%, and the balance is Fe and inevitable impurities. The inventors have found through research that the iron base material can be provided with a complete metallurgical reaction layer by hot dipping the iron base material in molten aluminum material at a temperature of 770-790℃. In order to prevent the aluminum-iron composite material from being weakened due to an excessively thick intermediate layer between the aluminum material and the iron base material, a higher temperature is not used for hot dipping.

[0025] In the step S2, the residual stress of the aluminum side of the aluminum-iron composite material is 60-90MPa.

[0026] S3, performing heat treatment on the aluminum-iron composite material.

[0027] In the embodiment of the present application, the cast aluminum-iron composite material is subjected to heat treatment at a certain temperature and for a certain time, so as to reduce the intermetallic interface stress of the aluminum-iron composite material, thereby weakening the stress of the aluminum side in the liquid-solid composite aluminum / iron bimetallic material, ensuring the integrity of the metallurgical bonding of the aluminum / iron bimetallic interface, and improving the shear strength of the aluminum / iron bimetallic material.

[0028] In the step S3, the residual stress of the aluminum side of the aluminum-iron composite material is between 12-18MPa.

[0029] Further, the shear strength of the aluminum-iron composite material is tested to be 15-35MPa.

[0030] Further, the average microhardness of the aluminum-iron composite material is tested to be 75-90HV (Vickers hardness), and the average microhardness is the average hardness of the aluminum within a range of 1cm at the interface of the aluminum-iron composite material.

[0031] The technical solutions of the present application are further described below in combination with specific embodiments.

[0032] Embodiment 1 The activated iron substrate was kept in a 550°C ceramic fiber heat treatment furnace for 2 minutes and 50 seconds to 350°C; the preheated iron substrate was hot-dipped in a 780°C aluminum alloy melt for 3 minutes; the hot-dipped iron substrate was clamped and placed in a 200°C mold and fixed, and a 710°C aluminum alloy melt was cast within 5 seconds to obtain an aluminum-iron composite material; a ceramic fiber furnace was used as the heat treatment furnace, and after the aluminum-iron composite material was cooled to room temperature, it was heated to the target temperature at a heating rate of 5°C / min in the heat treatment furnace, kept at 300°C for 3 hours, and then slowly furnace cooled to obtain the treated aluminum-iron composite material, which was then subjected to shear strength and microhardness tests, and its shear strength was 30.2MPa and its average microhardness was 87HV.

[0033] Example 2 The activated iron substrate was kept in a 550°C ceramic fiber heat treatment furnace for 2 minutes and 50 seconds to 350°C; the preheated iron substrate was hot-dipped in a 770°C aluminum alloy melt for 3 minutes; the hot-dipped iron substrate was clamped and placed in a 200°C mold and fixed, and a 700°C aluminum alloy melt was cast within 5 seconds to obtain an aluminum-iron composite material; a ceramic fiber furnace was used as the heat treatment furnace, and after the aluminum-iron composite material was cooled to room temperature, it was heated to the target temperature at a heating rate of 3°C / min in the heat treatment furnace, kept at 280°C for 2.5 hours, and then slowly furnace cooled to obtain the treated aluminum-iron composite material, which was then subjected to shear strength and microhardness tests, and the shear strength was 21MPa and the average microhardness was 88HV.

[0034] Example 3 The activated iron substrate was kept in a 550°C ceramic fiber heat treatment furnace for 2 minutes and 50 seconds to 350°C; the preheated iron substrate was hot-dipped in a 790°C aluminum alloy melt for 3 minutes; the hot-dipped iron substrate was clamped and placed in a 200°C mold and fixed, and a 720°C aluminum alloy melt was cast within 5 seconds to obtain an aluminum-iron composite material; a ceramic fiber furnace was used as the heat treatment furnace, and after the aluminum-iron composite material was cooled to room temperature, it was heated to the target temperature at a heating rate of 5°C / min in the heat treatment furnace, kept at 320°C for 3.5 hours, and then slowly furnace cooled to obtain the treated aluminum-iron composite material, which was then subjected to shear strength and microhardness tests, and the shear strength was 17 MPa and the average microhardness was 78 HV.

[0035] Comparative Example 1 The activated iron substrate was kept in a 550°C ceramic fiber heat treatment furnace for 2 minutes and 50 seconds to 350°C; the preheated iron substrate was hot-dipped in a 780°C aluminum alloy melt for 3 minutes; the hot-dipped iron substrate was clamped and placed in a 200°C mold and fixed, and a 710°C aluminum alloy melt was cast within 5 seconds to obtain an aluminum-iron composite material. Shear strength and microhardness tests were performed on the composite material, and the shear strength and average microhardness were 11.5MPa and 100HV, respectively.

[0036] Comparative Example 2 The activated iron substrate was kept in a 550°C ceramic fiber heat treatment furnace for 2 minutes and 50 seconds to 350°C; the preheated iron substrate was hot dipped in a 700°C aluminum alloy melt for 3 minutes; the hot-dipped iron substrate was clamped and placed in a 200°C mold and fixed, and a 710°C aluminum alloy melt was cast within 5 seconds to obtain an aluminum-iron composite material; a ceramic fiber furnace was used as the heat treatment furnace, and after the aluminum-iron composite material was cooled to room temperature, it was heated to the target temperature in the heat treatment furnace at a heating rate of 5°C / min, kept at 300°C for 3 hours, and then slowly cooled in the furnace to obtain the treated aluminum-iron composite material, which was then subjected to shear strength and microhardness tests. It was found that no metallurgical reaction layer was generated during the hot dip of the iron substrate in a 700°C aluminum alloy melt, and large cracks still existed.

[0037] Comparative Example 3 The activated iron substrate is kept in a 550°C ceramic fiber heat treatment furnace for 2 minutes and 50 seconds to 350°C; the preheated iron substrate is hot dipped in a 730°C aluminum alloy melt for 3 minutes; the hot-dipped iron substrate is clamped and placed in a 200°C mold and fixed, and a 710°C aluminum alloy melt is cast within 5 seconds to obtain an aluminum-iron composite material; a ceramic fiber furnace is used as the heat treatment furnace, and after the aluminum-iron composite material is cooled to room temperature, it is heated to the target temperature in the heat treatment furnace at a heating rate of 5°C / min, kept at 300°C for 3h, and then slowly furnace cooled to obtain the treated aluminum-iron composite material, and the shear strength test and microhardness test are performed on it. It is found that although a metallurgical reaction layer is partially generated in the process of hot dipping the iron substrate with a 730°C aluminum alloy melt, there are still some areas without a metallurgical reaction layer. These areas without a metallurgical reaction layer are mechanically riveted, with insufficient connection force and performance, and the shear strength is less than 6.7MPa.

[0038] Comparative Example 4 The activated iron substrate was kept in a 500°C ceramic fiber heat treatment furnace for 2 minutes to 340°C; the preheated iron substrate was hot-dipped in a 780°C aluminum alloy melt for 3 minutes; the hot-dipped iron substrate was clamped and placed in a 200°C mold and fixed, and a 700°C aluminum alloy melt was cast within 5 seconds to obtain an aluminum-iron composite material; a ceramic fiber furnace was used as the heat treatment furnace, and after the aluminum-iron composite material was cooled to room temperature, it was heated to the target temperature at a heating rate of 3°C / min in the heat treatment furnace, kept at 250°C for 3 hours, and then slowly furnace cooled to obtain the treated aluminum-iron composite material, which was then subjected to shear strength and microhardness tests, and the shear strength was 19 MPa and the microhardness was 89 HV.

[0039] Comparative Example 5 The activated iron substrate was kept in a 500°C ceramic fiber heat treatment furnace for 2 minutes to 340°C; the preheated iron substrate was hot-dipped in a 780°C aluminum alloy melt for 3 minutes; the hot-dipped iron substrate was clamped and placed in a 200°C mold and fixed, and a 700°C aluminum alloy melt was cast within 5 seconds to obtain an aluminum-iron composite material; a ceramic fiber furnace was used as the heat treatment furnace, and after the aluminum-iron composite material was cooled to room temperature, it was heated to the target temperature at a heating rate of 3°C / min in the heat treatment furnace, kept at 350°C for 3 hours, and then slowly cooled in the furnace to obtain the treated aluminum-iron composite material, which was then subjected to shear strength and microhardness tests, and the shear strength was 15MPa and the microhardness was 76HV.

[0040] See also Figure 1 , Figure 1 This is a microscopic image of the aluminum-iron composite material after heat treatment in Example 1, Comparative Example 4 and Comparative Example 5 of the present application, wherein: Figure 1 Figure a is a microscopic image of the aluminum-iron composite material obtained in Comparative Example 4 after being kept at 250°C for 3 hours and then furnace-cooled. Figure 1 Figure b is a microscopic image of the aluminum-iron composite material obtained in Example 1 after being kept at 300°C for 3 hours and then furnace-cooled. Figure 1 Figure c is a microscopic image of the aluminum-iron composite material obtained in comparative example 5 after being kept at 350°C for 3 hours and then cooled in the furnace. After being kept at different temperatures and removing the excess aluminum alloy, Figure 1 There are obvious cracks in the metallurgical reaction layer of a. Figure 1 There are no cracks in the metallurgical reaction layer of b. Figure 1 Narrow cracks also appeared in the metallurgical reaction layer of middle c.

[0041] See also Figure 2 , Figure 2This is the XRD stress diagram of the aluminum-iron composite material after heat treatment in Example 1 of the present application. The residual stress value on the aluminum side close to the metallurgical reaction layer of the aluminum-iron composite material is obtained by XRD residual stress testing after heat treatment. The residual stress value on the aluminum side is 15.2±1.6MPa, thereby ensuring the quality of the aluminum / iron bimetallic interface.

[0042] See also Figure 3 、 Figure 4 as well as Figure 5 , Figure 3 This is a microscopic image of the aluminum-iron composite material in Comparative Example 1 of this application. Figure 4 This is the XRD stress diagram of the aluminum-iron composite material in Comparative Example 1 of this application, Figure 5 The actual image and microscopic image of the aluminum-iron composite material after cutting in Comparative Example 1 of this application; Figure 3 The aluminum-iron composite material shown in the figure has a metallurgical reaction layer at the composite interface, and the metallurgical reaction layer is more straight, with a thickness of about 5μm. At this time, the interface is not cracked. Figure 4 The aluminum side of the aluminum-iron composite material has a residual stress of 73.9±10.1MPa. Figure 5 The aluminum-iron composite material in Comparative Example 1 is not subjected to heat treatment, and the excess aluminum alloy that bears the aluminum-iron interface stress is removed by wire cutting. Figure 5 Shown are the macroscopic image of the wire-cut part and the metallographic image of the aluminum-iron interface after stress release. It can be seen that the residual stress at the aluminum / iron bimetallic interface tears the metallurgical reaction layer, forming a crack of about 5μm.

[0043] See also Figure 6 and Figure 7 , Figure 6 This is a microscopic image of the aluminum-iron composite material in Comparative Examples 2 and 3 of the present application; Figure 7 Middle a, Figure 7 Middle b, Figure 7 c are microscopic images of the aluminum-iron composite materials that have not been heat-treated in Comparative Examples 1, 2 and 3 of the present application; Figure 6 Figure a is a microscopic image of an aluminum-iron composite material obtained by hot-dip dipping an iron matrix into a molten aluminum alloy at 700°C. Figure 6 Figure b is a microscopic image of an aluminum-iron composite material obtained by hot-dip dipping an iron matrix with molten aluminum alloy at 750°C. After heat treatment, even with corresponding temperature insulation treatment, heat treatment at 300°C for 3 hours is not enough to cause obvious element diffusion. No metallurgical reaction layer is generated under the hot-dip condition of 700°C, and there are still large cracks. Although some metallurgical reaction layer is generated during the hot-dip process at 730°C, there are still some areas without metallurgical reaction layer. These areas without metallurgical reaction layer are mechanically riveted, with insufficient connection force and performance. Figure 6 A and Figure 6 The specimen represented by b was subjected to shear strength test. Figure 6 The sample represented by a has no bonding, and the aluminum and iron have been separated during processing into a shear sample, Figure 6 The shear strength of the sample represented by b is only less than 6.7 MPa.

[0044] In the above examples, through the comparison of Example 1 and Comparative Example 1, the heat treatment method provided by the present application, i.e., heat treatment at 300℃ for 3h and then slow furnace cooling, although does not change the element composition of the metallurgical reaction layer, on the one hand reduces the residual stress on the aluminum side, and on the other hand, this annealing heat treatment can eliminate the composition segregation and dissolved non-equilibrium phase of the aluminum alloy, and these common factors can reduce the "pressure" of the aluminum side on the metallurgical reaction layer, thereby ensuring the bonding and shear strength of the aluminum / iron bimetallic metallurgical interface. The inventors found through Example and Comparative Examples 2 and 3 that selecting a temperature of 780±10℃ for hot dipping can achieve the technical effects in the heat treatment scheme of the present application; the inventors found through Example and Comparative Examples 4 and 5 that the heat treatment temperature and time of 280-320℃ for 2.5-3.5h can achieve the technical effects of the present application.

[0045] The present application controls the temperature during hot dipping of the iron base material and performs heat treatment on the cast aluminum-iron composite material at a certain temperature and time, thereby achieving the effect of reducing the intermetallic interface stress of the aluminum-iron composite material, on the one hand weakening the stress on the aluminum side in the liquid-solid composite aluminum / iron bimetal, and on the other hand ensuring the integrity of the aluminum / iron bimetallic interface metallurgical bonding and improving the shear strength of the aluminum / iron bimetal; on the other hand, after the release of the residual stress of the aluminum / iron bimetal, the as-cast aluminum / iron bimetal sample can be processed more freely and more selectively, and the aluminum / iron bimetallic interface is ensured to be intact after processing.

[0046] The above only describes the preferred embodiments of the present application, and does not limit the patent scope of the present application, and any equivalent structural transformation made according to the content of the present application, or direct / indirect application in other related technical fields is included in the patent protection scope of the present application.

Claims

1. A method for treating interface stress of aluminum-iron composite materials, characterized in that: The steps include: S1. Activate the surface of the iron substrate; S2. hot-dip the iron substrate with a first aluminum material, and cast the hot-dip iron substrate with a second aluminum material to obtain the aluminum-iron composite material, wherein the first aluminum material is a molten aluminum material at a temperature of 770-790° C., and the second aluminum material is a molten aluminum material at a temperature of 700-720° C.; S3. Heat the aluminum-iron composite material to 280-320° C. at a heating rate of 3-5° C. / min and keep the temperature for 2.5-3.5 hours.

2. The method for treating interface stress of aluminum-iron composite material according to claim 1, characterized in that: In the step S1, the activation treatment includes: grinding, alkali washing, and pickling.

3. The method for treating interface stress of aluminum-iron composite material according to claim 1, characterized in that: In the step S1, the iron substrate is iron or steel; in the step S2, the first aluminum material and the second aluminum material are aluminum or aluminum alloy.

4. The method for treating interface stress of aluminum-iron composite material according to claim 1, characterized in that: Before step S2, the method further includes: preheating the iron substrate.

5. The method for treating interface stress of aluminum-iron composite material according to claim 4, characterized in that: The preheating treatment is to keep the iron substrate at a temperature of 500-600°C for 2-3 minutes, so that the temperature of the iron substrate is raised to 340-360°C.

6. The method for treating interface stress of aluminum-iron composite material according to claim 1, characterized in that: After step S3, the method further includes: furnace cooling the aluminum-iron composite material.

7. The method for treating interface stress of aluminum-iron composite material according to claim 1, characterized in that: The aluminum-iron composite material comprises an aluminum coating, the aluminum coating comprises a metallurgical reaction layer and a hot-dip melt layer, the metallurgical reaction layer comprises Al5Fe2, Al 13 Fe4, the thickness of the metallurgical reaction layer is 4-6 μm, and the thickness of the aluminum coating is 10-14 μm.

8. The method for treating interface stress of aluminum-iron composite material according to claim 4, characterized in that: In the step S2, the residual stress on the aluminum side of the aluminum-iron composite material is 60-90 MPa.

9. The method for treating interface stress of aluminum-iron composite material according to claim 6, characterized in that: In step S3, the residual stress on the aluminum side of the aluminum-iron composite material is between 12 MPa and 18 MPa.

10. An aluminum-iron composite material, characterized in that: The aluminum-iron composite material is prepared by the aluminum-iron composite material interface stress treatment method according to any one of claims 1 to 9.

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