Aluminum-iron composite material based on micro-texture cross-section morphology optimization and preparation method thereof

Abstract

This application belongs to the field of cemented carbide technology, specifically relating to an aluminum-iron composite material based on microtexture cross-sectional morphology optimization and its preparation method. The preparation method includes the following steps: S1, obtaining an iron substrate, a first aluminum substrate, and a second aluminum substrate; grinding the iron substrate to obtain the first iron substrate; S2, laser etching the first iron substrate to obtain the second iron substrate; S3, heating the first aluminum substrate to obtain a first aluminum substrate melt, using the first aluminum substrate melt to hot-dip the second iron substrate to obtain a third iron substrate, heating the second aluminum substrate to obtain a second aluminum substrate melt, and using the second aluminum substrate melt to cast the third iron substrate to obtain the aluminum-iron composite material. This application achieves an interface sandwich structure by laser pretreatment of the iron substrate to form a moderately deep, semi-circular microtexture at the bottom, combined with liquid-solid composite casting, significantly improving the aluminum-iron bonding performance.

Description

Technical Field

[0001] This application belongs to the field of cemented carbide technology, specifically relating to an aluminum-iron composite material based on microtexture cross-sectional morphology optimization and its preparation method. Background Technology

[0002] With the rapid development of high-precision and high-reliability in the high-end equipment manufacturing industry, traditional single-metal materials can no longer meet the performance requirements of structural materials in harsh service environments. Liquid-solid composite casting of aluminum / iron bimetals can fully leverage the high strength and excellent wear resistance of iron-based materials with the lightweight, good corrosion resistance, and high thermal conductivity of aluminum-based materials, achieving complementary performance. This material can significantly improve structural strength and service performance while meeting lightweight design requirements, providing a new option for developing high-performance lightweight structural materials. However, due to the significant differences in the thermophysical properties (such as coefficients of thermal expansion and thermal conductivity) of aluminum and iron, thermal stress concentration is prone to occur at the interface during liquid-solid composite casting. When subjected to external forces, brittle fracture easily occurs at the interface, leading to early cracking, which seriously affects the reliability and safety of structural components, thus restricting the engineering application of aluminum / iron bimetals.

[0003] To address the aforementioned challenges, preheating or hot-dip galvanizing of the iron substrate is commonly employed to reduce the temperature difference between the solid iron substrate and the molten aluminum alloy, accommodating interfacial thermal expansion and solidification shrinkage deformation, thereby improving interfacial bonding to some extent. However, to prevent oxidation of the iron substrate surface during preheating, the preheating temperature is limited and cannot be too high, offering little effect in regulating interfacial thermal stress. While hot-dip galvanizing can raise the substrate temperature to near that of the molten aluminum alloy in a short time, its primary purpose is to prevent high-temperature oxidation of the iron substrate surface and alter the composition of the interfacial reaction layer by pre-plating a low-melting-point metal. Therefore, neither preheating nor hot-dip galvanizing effectively controls the concentration and release of localized interfacial thermal stress, leading to unstable interfacial bonding and a risk of cracking during subsequent machining.

[0004] Existing technologies employ laser microtexturing of iron substrates to improve interfacial bonding strength. However, these methods primarily focus on the presence of water to protect the iron substrate surface from oxidation during laser etching. Furthermore, optimization of equipment parameters such as laser power and frequency is necessary to enhance the interfacial bonding strength in subsequent liquid-solid bimetallic composite processes. The laser microtexturing process is complex, and the impact of microtextured cross-sectional morphology on the interfacial reaction layer structure and bonding performance during liquid-solid composite processes is not adequately addressed. Therefore, a method for preparing aluminum-iron composite materials based on microtexturing is urgently needed. This method is simple to operate, unaffected by environmental media, and can effectively improve interfacial bonding capabilities. Summary of the Invention

[0005] To address the aforementioned technical problems, this application provides a method for preparing an aluminum-iron composite material based on optimized microtexture cross-sectional morphology, comprising the following steps: S1, obtaining an iron substrate and an aluminum substrate, wherein the aluminum substrate includes a first aluminum substrate and a second aluminum substrate; grinding, cleaning, and drying the iron substrate to obtain a first iron substrate; S2, performing laser etching, alkaline washing, acid washing, cleaning, and drying on the first iron substrate to obtain a second iron substrate; the laser etching processing speed is 460-500 mm / s, the number of laser etching processes is 14-16, the surface of the second iron substrate has a microtexture, the depth of the grooves in the microtexture is 100-120 μm, and the bottom shape of the cross-section of the grooves in the microtexture is semi-circular; S3, heating the first aluminum substrate to obtain a first aluminum substrate melt, using the first aluminum substrate melt to hot-dip the second iron substrate to obtain a third iron substrate, heating the second aluminum substrate to obtain a second aluminum substrate melt, and using the second aluminum substrate melt to cast the third iron substrate to obtain an aluminum-iron composite material.

[0006] As a preferred embodiment of the method for preparing aluminum-iron composite materials based on microtexture cross-sectional morphology optimization described in this application, in step S1, the type of iron substrate is one of ductile iron, carbon steel, alloy steel, and stainless steel; the type of aluminum substrate is one of pure aluminum, aluminum-silicon alloy, and aluminum-copper alloy.

[0007] As a preferred embodiment of the preparation method of aluminum-iron composite material based on microtexture cross-sectional morphology optimization described in this application, in step S1, the grinding method is specifically as follows: the substrate surface is ground sequentially with 200-grit, 400-grit, 800-grit, and 1000-grit sandpaper to remove rust from the substrate surface and make the substrate smooth and glossy.

[0008] As a preferred embodiment of the method for preparing aluminum-iron composite material based on microtexture cross-sectional morphology optimization described in this application, in step S2, the laser power of the laser etching is 30W and the laser frequency of the laser etching is 20Hz.

[0009] As a preferred embodiment of the preparation method of aluminum-iron composite material based on microtexture cross-sectional morphology optimization described in this application, in step S2, the alkaline washing method is specifically as follows: the substrate is placed in a 10wt% NaOH solution and ultrasonically alkaline washed 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 off with running water; the acid washing method is specifically as follows: the substrate is placed in a 10wt% HCl solution and ultrasonically acid washed for 10 minutes to further remove the oxide scale on the surface of the substrate to expose a fresh metal surface, and then the residual acid solution on the surface of the substrate is rinsed off with running water.

[0010] As a preferred embodiment of the method for preparing aluminum-iron composite material based on microtexture cross-sectional morphology optimization described in this application, step S3 further includes degassing the first aluminum substrate melt and the second aluminum substrate melt; the temperature of the first aluminum substrate melt is 730°C and the temperature of the second aluminum substrate melt is 710°C.

[0011] As a preferred embodiment of the preparation method of aluminum-iron composite material based on microtexture cross-sectional morphology optimization described in this application, in step S3, the hot dipping method specifically involves: after the second iron substrate is kept at 320°C for 8 minutes, it is immediately taken out and immersed in the first aluminum substrate melt for 150 seconds to obtain the third iron substrate; the casting method specifically involves: placing the third iron substrate in a metal mold at a temperature of 200°C, and pouring the second aluminum substrate melt into the mold to obtain the aluminum-iron composite material.

[0012] This application also provides an aluminum-iron composite material based on microtexture cross-sectional morphology optimization, which is prepared by the above-described method for preparing aluminum-iron composite materials based on microtexture cross-sectional morphology optimization.

[0013] As a preferred embodiment of the aluminum-iron composite material based on microtexture cross-sectional morphology optimization described in this application, the interfacial microtexture region of the aluminum-iron composite material exhibits a hard-soft-hard sandwich structure with alternating "reaction layer-aluminum substrate-reaction layer".

[0014] As a preferred embodiment of the aluminum-iron composite material based on microtexture cross-sectional morphology optimization described in this application, the interfacial shear strength of the aluminum-iron composite material is ≥70MPa.

[0015] This study found that during the liquid-solid composite process, the wettability between the molten aluminum alloy and the solid iron substrate at the moment of contact directly affects the spread of the molten aluminum on the surface of the solid iron substrate, thus influencing the liquid-solid interface reaction. Therefore, from the perspective of interface microstructure design, a laser pretreatment method is used to pre-form uniformly distributed microtextures on the surface of the iron substrate. By controlling the number of laser processing cycles and the processing speed, the depth of the grooves in the microtextures is ensured to be between 100-120 μm, with a semi-circular bottom. This alters the wettability between the molten aluminum alloy and the solid iron substrate surface during the liquid-solid composite process, regulates the distribution of residual stress at the interface during solidification, and ultimately improves the interfacial bonding ability.

[0016] The beneficial effects of this application are as follows: This application provides an aluminum-iron composite material based on optimized microtexture cross-sectional morphology and its preparation method. This application utilizes laser pretreatment of the iron substrate to form a moderately deep, semi-circular microtexture at the bottom, combined with liquid-solid composite casting, to achieve an interfacial sandwich structure, significantly improving the aluminum-iron bonding performance. This application employs laser surface pretreatment technology. By controlling the laser process parameters, when the depth of the microtexture grooves is within a certain range and the bottom is semi-circular, it not only increases the wettability of the liquid-solid interface but also induces the growth path of the interfacial reaction layer, thereby altering the interfacial stress distribution behavior and preventing early interfacial cracking. This method is simple to operate, unaffected by environmental media, and significantly improves the interfacial bonding effect.

[0017] This application first sands the surface of the iron substrate; then, it performs laser pretreatment on the surface to create a microtexture. The grooves of the microtexture are 100-120 μm deep and have a semi-circular bottom. The iron substrate with the microtexture is then subjected to liquid-solid composite casting. An interfacial reaction layer is formed between the aluminum substrate and the microtextured iron substrate. This interfacial reaction layer grows continuously along the iron substrate, and the aluminum substrate melt fills well in the microtextured area, resulting in a continuous and stable reaction layer. However, unlike the previous method, the reaction layer in the microtextured area grows along its cross-sectional texture, forming a "reaction layer-aluminum substrate-reaction layer" sandwich structure, rather than the nearly straight reaction layer without microtexture. The presence of microtexture does not change the phase composition of the interfacial reaction layer, which is still dominated by aluminum-iron binary intermetallic compounds. The aluminum-iron binary intermetallic compounds are hard and brittle phases. Therefore, the "reaction layer-aluminum substrate-reaction layer" sandwich structure formed by microtexture is actually a hard-soft-hard alternating structure. This structure is beneficial to alleviate sudden changes in interfacial stress and coordinate interfacial deformation during the stress process, and significantly improves the interfacial bonding performance of liquid-solid composite cast aluminum / iron bimetals.

[0018] If the grooves in the microtexture are too deep, it will lead to poor filling of the aluminum substrate melt, resulting in porosity defects at the interface. If the grooves are too shallow, the interface will be similar to that without microtexture under the scouring and diffusion effects of the aluminum alloy melt. If the microtexture cross-section is sharp, it will either cause pore defects due to poor filling or cause the reaction layer in the microtexture area to connect into sheets, leading to stress concentration and cracking. Therefore, the microtexture cross-sectional morphology pre-formed on the iron substrate surface by laser pretreatment must ensure that the depth is moderate and the bottom is semi-circular to guarantee a significant improvement in interfacial bonding performance.

[0019] This study also found that the number of processing cycles and the processing speed of the laser processing equipment affect the depth and bottom shape of the grooves in the microtexture. When the laser power is 30W, the laser frequency is 20Hz, the processing speed is 460-500mm / s, and the number of processing cycles is 14-16, which can ensure that the bottom shape of the processed microtexture cross section is semi-circular and the depth is between 100-120μm. This is because higher processing speeds result in shorter laser dwell times, leading to instantaneous vaporization of the substrate surface, less molten residue, and a smaller heat-affected zone. The bottom is more likely to form an arc shape, but the trench depth tends to be shallower. Conversely, slower processing speeds result in longer laser dwell times, leading to a large accumulation of molten material, significant sidewall thermal deformation, and a wider trench opening and narrower bottom. Fewer processing passes result in less heat accumulation in the processing area, less molten loss on the substrate surface, and a shallower trench depth, but it is easier to maintain the stability of the semi-circular bottom geometry. Excessive processing passes lead to repeated heat accumulation in the processing area, resulting in a larger heat-affected zone, deeper trenches, and, combined with sidewall collapse, a gradually sharpening of the trench bottom. Therefore, by synergistically controlling the processing speed at 460-500 mm / s and the number of passes at 14-16, the cross-sectional morphology of the microtexture can be guaranteed, thereby ensuring the bonding performance of the bimetallic interface.

[0020] Compared to traditional liquid-solid composite casting technology, this application innovatively performs laser pretreatment on the iron substrate, resulting in a uniformly distributed microtexture of moderate depth (100-120 μm) with a semi-circular bottom on its surface. On one hand, the presence of the microtexture significantly enhances the wettability of the liquid-solid interface; on the other hand, the reaction layer morphology formed in the microtextured region facilitates coordinated interface deformation during stress and alleviates interface stress concentration under conditions without microtexture, thereby significantly improving interfacial bonding performance. Furthermore, compared to conventional iron substrate preheating and single hot-dip galvanizing methods, laser pretreatment is a highly efficient, low-cost, portable, and environmentally friendly technology, unrestricted by substrate specifications or environmental factors, and perfectly suitable for industrial applications of large and complex structural components. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0022] Figure 1 This is a cross-sectional morphology diagram of the microtexture prepared in Example 1 of this application; Figure 2 This is a cross-sectional morphology diagram of the aluminum-iron composite material prepared in Example 1 of this application; Figure 3 This is a cross-sectional morphology diagram of the microtexture prepared in Comparative Example 2 of this application; Figure 4 This is a cross-sectional morphology diagram of the aluminum-iron composite material prepared in Comparative Example 2 of this application; Figure 5 This is a cross-sectional morphology diagram of the microtexture prepared in Comparative Example 4 of this application; Figure 6 This is a cross-sectional morphology diagram of the aluminum-iron composite material prepared in Comparative Example 4 of this application; Figure 7 This is a cross-sectional morphology diagram of the microtexture prepared in Comparative Example 6 of this application; Figure 8 This is a cross-sectional morphology diagram of the aluminum-iron composite material prepared in Comparative Example 6 of this application.

[0023] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0024] The technical solutions in the embodiments will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0025] This application provides a method for preparing aluminum-iron composite materials based on microtexture cross-sectional morphology optimization, including the following steps: S1. Obtain an iron substrate and an aluminum substrate, wherein the aluminum substrate includes a first aluminum substrate and a second aluminum substrate; grind, clean, and dry the iron substrate to obtain the first iron substrate. The iron substrate is one of ductile iron, carbon steel, alloy steel, and stainless steel; the aluminum substrate is one of pure aluminum, aluminum-silicon alloy, and aluminum-copper alloy; the polishing method is as follows: the substrate surface is polished in sequence with 200 grit, 400 grit, 800 grit, and 1000 grit sandpaper to remove rust and make the substrate smooth and shiny. S2. The first iron substrate is subjected to laser etching, alkaline washing, acid washing, cleaning, and drying to obtain a second iron substrate; the laser etching speed is 460-500 mm / s, the number of laser etching operations is 14-16, the surface of the second iron substrate has a microtexture, the depth of the grooves of the microtexture is 100-120 μm, and the bottom shape of the cross-section of the grooves of the microtexture is semi-circular; Specifically, the laser etching speed is any one or any two of 460mm / s, 465mm / s, 470mm / s, 475mm / s, 480mm / s, 485mm / s, 490mm / s, 495mm / s, and 500mm / s; the number of laser etching operations is any one or any two of 14, 15, and 16. The laser etching uses a laser power of 30W and a laser frequency of 20Hz. The alkaline cleaning method specifically involves placing the substrate in a 10wt% NaOH solution and ultrasonically cleaning it for 5 minutes to remove oil stains from the substrate surface, followed by rinsing off any remaining alkaline solution with running water. The acid cleaning method specifically involves placing the substrate in a 10wt% HCl solution and ultrasonically acid cleaning it for 10 minutes to further remove the oxide scale from the substrate surface, exposing a fresh metal surface, followed by rinsing off any remaining acid solution with running water. S3. Heating the first aluminum substrate to obtain a first aluminum substrate melt, using the first aluminum substrate melt to hot-dip the second iron substrate to obtain a third iron substrate, heating the second aluminum substrate to obtain a second aluminum substrate melt, using the second aluminum substrate melt to cast the third iron substrate to obtain an aluminum-iron composite material.

[0026] Step S3 further includes degassing the first aluminum substrate melt and the second aluminum substrate melt; the temperature of the first aluminum substrate melt is 730°C and the temperature of the second aluminum substrate melt is 710°C; the hot dipping method is specifically as follows: after the second iron substrate is kept at 320°C for 8 minutes, it is immediately taken out and immersed in the first aluminum substrate melt for 150 seconds to obtain the third iron substrate; the casting method is specifically as follows: the third iron substrate is placed in a metal mold at a temperature of 200°C, and the second aluminum substrate melt is poured into the mold to obtain an aluminum-iron composite material.

[0027] This application also provides an aluminum-iron composite material based on microtextured cross-sectional morphology optimization, comprising: the interfacial microtextured region of the aluminum-iron composite material presents a hard-soft-hard sandwich structure with alternating "reaction layer-aluminum substrate-reaction layer", and the interfacial shear strength of the aluminum-iron composite material is ≥70MPa.

[0028] The technical solution of this application will be further described below with reference to specific embodiments.

[0029] Example 1 A method for preparing aluminum-iron composite materials based on microtexture cross-sectional morphology optimization, the method comprising the following steps: S1. Obtain an iron substrate and an aluminum substrate, wherein the aluminum substrate includes a first aluminum substrate and a second aluminum substrate; grind, clean and dry the iron substrate to obtain the first iron substrate. The iron-based material is ductile iron QT500, and by weight percentage, its composition is: C: 3.7wt%, Si: 2.7wt%, Mn: 0.4wt%, S: 0.02wt%, P: 0.05wt%, Mg: 0.04wt%, with the balance being Fe and unavoidable impurities. The aluminum-based material is Al-Si alloy ZL702A; by weight percentage, its composition is: Si: 7.0wt%, Mg: 0.2wt%, Cu: 1.5wt%, Mn: 0.14wt%, Fe: 0.12wt%, with the balance being Al and unavoidable impurities. The specific sanding method is as follows: use 200 grit, 400 grit, 800 grit and 1000 grit sandpaper to sand the surface of the substrate in sequence to remove rust from the substrate surface and make the substrate smooth and shiny; S2. The first iron substrate is subjected to laser etching, alkaline washing, acid washing, cleaning, and drying to obtain the second iron substrate; the laser etching speed is 480 mm / s, the number of laser etching operations is 15, the laser power is 30 W, and the laser frequency is 20 Hz; the surface of the second iron substrate has a microtexture, please refer to [reference needed]. Figure 1 , Figure 1 This is a cross-sectional topography of the microtexture prepared in Example 1 of this application; the depth of the grooves in the microtexture is 110 μm, and the bottom shape of the cross-section of the grooves in the microtexture is semi-circular; The specific alkaline washing method is as follows: place the substrate in a 10wt% NaOH solution and ultrasonically wash for 5 minutes to remove oil stains on the surface of the substrate, and then rinse off the residual alkaline solution on the surface of the substrate with running water. The pickling method is as follows: the substrate is placed in a 10wt% HCl solution and ultrasonically pickled for 10 minutes to further remove the oxide scale on the surface of the substrate to expose a fresh metal surface. Then, the residual acid on the surface of the substrate is rinsed off with running water. S3. Heating the first aluminum substrate to obtain the first aluminum substrate melt, using the first aluminum substrate melt to hot-dip the second iron substrate to obtain the third iron substrate, heating the second aluminum substrate to obtain the second aluminum substrate melt, using the second aluminum substrate melt to cast the third iron substrate to obtain the aluminum-iron composite material.

[0030] Step S3 further includes degassing the first aluminum substrate melt and the second aluminum substrate melt; the temperature of the first aluminum substrate melt is 730°C and the temperature of the second aluminum substrate melt is 710°C. The hot-dip method is as follows: after the second iron substrate is kept at 320°C for 8 minutes, it is immediately taken out and immersed in the first aluminum substrate melt for 150 seconds to obtain the third iron substrate. The specific casting method is as follows: the third iron substrate is placed in a metal mold at a temperature of 200°C, and the molten second aluminum substrate is poured into the mold to obtain an aluminum-iron composite material.

[0031] The prepared aluminum-iron composite material was tested, and the results showed that: (Please refer to...) Figure 2 , Figure 2 This is a cross-sectional morphology diagram of the aluminum-iron composite material prepared in Example 1 of this application; the interfacial microtexture region of the aluminum-iron composite material exhibits a hard-soft-hard sandwich structure with alternating "reaction layer-aluminum substrate-reaction layer" and the interfacial shear strength of the aluminum-iron composite material is 75 MPa.

[0032] Example 2 The difference between this embodiment and Embodiment 1 is that the laser etching processing speed is 460 mm / s, the number of laser etching processes is 14, the surface of the second iron substrate has a microtexture, the depth of the grooves of the microtexture is 101 μm, and the bottom shape of the cross-section of the grooves of the microtexture is semi-circular; the other steps are the same as in Embodiment 1.

[0033] The prepared aluminum-iron composite material was tested, and the results showed that the interfacial microtexture region of the aluminum-iron composite material exhibited a hard-soft-hard sandwich structure with alternating "reaction layer-aluminum substrate-reaction layer" and the interfacial shear strength of the aluminum-iron composite material was 70 MPa.

[0034] Example 3 The difference between this embodiment and Embodiment 1 is that the laser etching processing speed is 500 mm / s, the number of laser etching processes is 16, the surface of the second iron substrate has a microtexture, the depth of the grooves of the microtexture is 115 μm, and the bottom shape of the cross-section of the grooves of the microtexture is semi-circular; the other steps are the same as in Embodiment 1.

[0035] The prepared aluminum-iron composite material was tested, and the results showed that the interfacial microtexture region of the aluminum-iron composite material exhibited a hard-soft-hard sandwich structure with alternating "reaction layer-aluminum substrate-reaction layer" and the interfacial shear strength of the aluminum-iron composite material was 72 MPa.

[0036] Comparative Example 1 The difference between this comparative example and Example 1 is that the laser etching speed is 420 mm / s, the surface of the second iron substrate has a microtexture, the depth of the grooves in the microtexture is 75 μm, and the bottom shape of the cross-section of the grooves in the microtexture is sharp; all other steps are the same as in Example 1.

[0037] The prepared aluminum-iron composite material was tested, and the results showed that the interfacial microtexture region of the aluminum-iron composite material only had a reaction layer and no alternating soft and hard structure. The interfacial shear strength of the aluminum-iron composite material was 24 MPa.

[0038] Comparative Example 2 The difference between this comparative example and Example 1 is that the laser etching speed is 520 mm / s, and the surface of the second iron substrate has a microtexture. Please refer to [link to example]. Figure 3 , Figure 3 This is a cross-sectional morphology diagram of the microtexture prepared in Comparative Example 2 of this application; the depth of the grooves in the microtexture is 48 μm, and the bottom shape of the cross-section of the grooves in the microtexture is semi-circular; the other steps are the same as in Example 1.

[0039] The prepared aluminum-iron composite material was tested, and the results showed that: (Please refer to...) Figure 4 , Figure 4 This is a cross-sectional morphology diagram of the aluminum-iron composite material prepared in Comparative Example 2 of this application; the interfacial microtexture region of the aluminum-iron composite material exhibits a hard-soft-hard sandwich structure with alternating "reaction layer-aluminum substrate-reaction layer" and the interfacial shear strength of the aluminum-iron composite material is 14 MPa.

[0040] Comparative Example 3 The difference between this comparative example and Example 1 is that the laser etching process is performed 12 times, the surface of the second iron substrate has a microtexture, the depth of the grooves in the microtexture is 80 μm, and the bottom shape of the cross-section of the grooves in the microtexture is semi-circular; all other steps are the same as in Example 1.

[0041] The prepared aluminum-iron composite material was tested, and the results showed that the interfacial microtexture region of the aluminum-iron composite material exhibited a hard-soft-hard sandwich structure with alternating "reaction layer-aluminum substrate-reaction layer" and the interfacial shear strength of the aluminum-iron composite material was 20 MPa.

[0042] Comparative Example 4 The difference between this comparative example and Example 1 is that the laser etching process is repeated 18 times, and the surface of the second iron substrate has a microtexture. Please refer to [link to example]. Figure 5 , Figure 5 This is a cross-sectional morphology diagram of the microtexture prepared in Comparative Example 4 of this application; the depth of the grooves in the microtexture is 113 μm, and the bottom shape of the cross-section of the grooves in the microtexture is sharp; the other steps are the same as in Example 1.

[0043] The prepared aluminum-iron composite material was tested, and the results showed that: (Please refer to...) Figure 6 , Figure 6 This is a cross-sectional morphology diagram of the aluminum-iron composite material prepared in Comparative Example 4 of this application; the entire interfacial microtexture region of the aluminum-iron composite material is a reaction layer and cracks are present, and the interfacial shear strength of the aluminum-iron composite material is 28 MPa.

[0044] Comparative Example 5 The difference between this comparative example and Example 1 is that the laser etching speed is 420 mm / s, the number of laser etching operations is 12, the surface of the second iron substrate has a microtexture, the depth of the grooves in the microtexture is 62 μm, and the bottom shape of the cross-section of the grooves in the microtexture is semi-circular; all other steps are the same as in Example 1.

[0045] The prepared aluminum-iron composite material was tested, and the results showed that the interfacial microtexture region of the aluminum-iron composite material exhibited a hard-soft-hard sandwich structure with alternating "reaction layer-aluminum substrate-reaction layer" and the interfacial shear strength of the aluminum-iron composite material was 27 MPa.

[0046] Comparative Example 6 The difference between this comparative example and Example 1 is that the laser etching speed is 520 mm / s, the number of laser etching operations is 18, and the surface of the second iron substrate has a microtexture. Please refer to [link to example]. Figure 7 , Figure 7 This is a cross-sectional morphology diagram of the microtexture prepared in Comparative Example 6 of this application; the depth of the grooves in the microtexture is 176 μm, and the bottom shape of the cross-section of the grooves in the microtexture is sharp; the other steps are the same as in Example 1.

[0047] The prepared aluminum-iron composite material was tested, and the results showed that: (Please refer to...) Figure 8 , Figure 8 This is a cross-sectional morphology diagram of the aluminum-iron composite material prepared in Comparative Example 6 of this application; the entire interfacial microtexture region of the aluminum-iron composite material is a reaction layer, and there is insufficient filling. The interfacial shear strength of the aluminum-iron composite material is 20 MPa.

[0048] A comparison of the performance data of the above embodiments and comparative examples shows that: Example 1, in conjunction with Comparative Example 1, shows that when the number of processing cycles remains constant, as the processing speed decreases, the time the laser interacts with the substrate increases, leading to increased thermal deformation of the trench sidewalls, narrowing of the bottom, sharpening of the microtexture cross-section, and poor interfacial shear strength.

[0049] Example 1, in conjunction with Comparative Example 2, shows that when the number of processing cycles remains constant, as the processing speed increases, the laser action time on the substrate becomes shorter, resulting in a shallower groove depth in the microtexture. The effect is similar to that without microtexture, and it cannot improve the interfacial bonding performance.

[0050] Example 1, in conjunction with Comparative Example 3, shows that when the processing speed remains constant, as the number of processing cycles decreases, the heat accumulation in a single groove is less, and the bottom is more likely to form a semi-circle, but the depth is significantly reduced. During the liquid-solid composite process, the microtexture is further dissolved, the width at the opening increases, and the area of ​​the alternating soft and hard structure at the interface decreases, which is not conducive to the improvement of mechanical properties.

[0051] Example 1, in conjunction with Comparative Example 4, shows that when the processing speed remains constant, although the microtexture depth does not change significantly with the increase of the number of processing cycles, the substrate is affected by repeated heat accumulation and sidewall collapse, which causes the grooves at the bottom of the microtexture to narrow, resulting in the close connection of the reaction layers on both sides. Stress concentration causes cracks to form, thus making the interface a brittle and weak area.

[0052] Example 1, in conjunction with Comparative Example 5, shows that as the processing speed and number of processing cycles decrease, the depth of the microtexture becomes shallower. Although the semi-circular bottom of the groove is easily formed, the liquid-solid composite process leads to further melting of the microtexture, an increase in the width of the opening, and a reduction in the area of ​​the alternating soft and hard interface structure, which is not conducive to the improvement of mechanical properties.

[0053] Example 1, in conjunction with Comparative Example 6, shows that as the processing speed and number of processing cycles increase, the depth of the microtexture continuously increases, and the bottom of the groove gradually becomes sharper. This results in the aluminum melt not being able to fully fill the microtexture during the liquid-solid composite process, causing void defects to form in the area where the microtexture is located, thus weakening the mechanical properties.

[0054] The above description is only a preferred embodiment of this application and does not limit the patent scope of this application. All equivalent structural transformations made using the content of this application's specification under the inventive concept of this application, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this application.

Claims

1. A method for preparing aluminum-iron composite material based on micro-texture cross-sectional morphology optimization, characterized in that, Includes the following steps: S1. Obtain an iron substrate and an aluminum substrate, wherein the aluminum substrate includes a first aluminum substrate and a second aluminum substrate; grind, clean, and dry the iron substrate to obtain the first iron substrate. S2. The first iron substrate is subjected to laser etching, alkaline washing, acid washing, cleaning, and drying to obtain a second iron substrate; the laser etching speed is 460-500 mm / s, the number of laser etching operations is 14-16, the surface of the second iron substrate has a microtexture, the depth of the grooves of the microtexture is 100-120 μm, and the bottom shape of the cross-section of the grooves of the microtexture is semi-circular; S3. Heating the first aluminum substrate to obtain a first aluminum substrate melt, using the first aluminum substrate melt to hot-dip the second iron substrate to obtain a third iron substrate, heating the second aluminum substrate to obtain a second aluminum substrate melt, using the second aluminum substrate melt to cast the third iron substrate to obtain an aluminum-iron composite material.

2. The method for preparing aluminum-iron composite materials based on microtexture cross-sectional morphology optimization according to claim 1, characterized in that, In step S1, the type of iron substrate is one of ductile iron, carbon steel, alloy steel, and stainless steel; the type of aluminum substrate is one of pure aluminum, aluminum-silicon alloy, and aluminum-copper alloy.

3. The method for preparing aluminum-iron composite materials based on microtexture cross-sectional morphology optimization according to claim 1, characterized in that, In step S1, the polishing method is as follows: the substrate surface is polished sequentially with 200-grit, 400-grit, 800-grit, and 1000-grit sandpaper to remove rust and make the substrate smooth and glossy.

4. The method for preparing aluminum-iron composite materials based on microtexture cross-sectional morphology optimization according to claim 1, characterized in that, In step S2, the laser power of the laser etching is 30W, and the laser frequency of the laser etching is 20Hz.

5. The method for preparing aluminum-iron composite materials based on microtexture cross-sectional morphology optimization according to claim 1, characterized in that, In step S2, the alkaline washing method is as follows: the substrate is placed in a 10wt% NaOH solution and ultrasonically alkaline washed 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 off with running water; the acid washing method is as follows: the substrate is placed in a 10wt% HCl solution and ultrasonically acid washed for 10 minutes to further remove the oxide scale on the surface of the substrate to expose a fresh metal surface, and then the residual acid solution on the surface of the substrate is rinsed off with running water.

6. The method for preparing aluminum-iron composite materials based on microtexture cross-sectional morphology optimization according to claim 1, characterized in that, Step S3 further includes degassing the first aluminum substrate melt and the second aluminum substrate melt; the temperature of the first aluminum substrate melt is 730°C and the temperature of the second aluminum substrate melt is 710°C.

7. The method for preparing aluminum-iron composite materials based on microtexture cross-sectional morphology optimization according to claim 1, characterized in that, In step S3, the hot dipping method is specifically as follows: after the second iron substrate is kept at 320°C for 8 minutes, it is immediately taken out and immersed in the first aluminum substrate melt for 150 seconds to obtain the third iron substrate; the casting method is specifically as follows: the third iron substrate is placed in a metal mold at a temperature of 200°C, and the second aluminum substrate melt is poured into the mold to obtain an aluminum-iron composite material.

8. An aluminum-iron composite material based on microtexture cross-sectional morphology optimization, characterized in that, The aluminum-iron composite material was prepared using the method described in any one of claims 1-7, which is based on the optimization of microtexture cross-sectional morphology.

9. An aluminum-iron composite material based on microtexture cross-sectional morphology optimization according to claim 8, characterized in that, The interfacial microtexture region of the aluminum-iron composite material exhibits a hard-soft-hard sandwich structure with alternating "reaction layer-aluminum substrate-reaction layer".

10. An aluminum-iron composite material based on microtexture cross-sectional morphology optimization according to claim 8, characterized in that, The interfacial shear strength of the aluminum-iron composite material is ≥70MPa.

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