Additive preparation method and application of aluminum-steel composite material

Abstract

The invention discloses an additive preparation method and application of an aluminum-steel composite material. The additive preparation method comprises the following steps: S1, carrying out laser preheating treatment on an aluminum alloy raw material to obtain an aluminum alloy; and S2, aluminum alloy material increase is conducted on the base material steel plate through a friction stir material increase technology, and the aluminum-steel composite material is obtained. According to the method, solid-phase additive materials are combined with various external source auxiliary process technologies, a laser heat source is introduced in the stirring friction additive material process to preheat the aluminum alloy raw materials, the material softening degree can be well improved, the metal fluidity in the additive material process is improved, heat input needed in the additive material process is reduced, and cracks, air holes and other defects are effectively avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of aluminum alloys, and in particular to a forming method of an aluminum alloy and application thereof. Background Art

[0002] Aluminum-steel composite materials have great demand in the industry because they have the advantages of low density and corrosion resistance of aluminum and its alloys and high strength of steel. For example, the use of aluminum-steel composite materials on ships can play a role in firmly connecting the deck (steel material) and the cabin (aluminum alloy), thereby ensuring the safe operation of the ship. However, the physical and chemical properties of aluminum alloy and steel are quite different, and the traditional melting welding cannot achieve effective connection of the two materials. The main advantages of the rolling composite method include: it can composite metal plates, bars, pipes, and wires, and it has low cost, high output, mature technology, and is suitable for large-scale industrial production. The main disadvantages include: the oxidation of raw materials cannot be avoided during the production process of rolling composite, and the bonding between the two metals is unstable, which is a typical mechanical bonding. When aluminum-steel composite materials are prepared by explosive welding, due to the poor chemical or metallurgical compatibility of aluminum and iron elements, a large number of compounds are easily generated at the interface. These compounds are hard and brittle, which seriously affect the bonding quality of the composite materials and make the materials unable to be used in engineering. Therefore, in the actual production process, in order to improve the bonding quality of aluminum-steel composite materials, pure titanium or pure aluminum is often introduced as a transition layer between aluminum alloy and steel materials to improve the bonding quality of the composite materials. However, the interface is the weak point of the composite material. If a transition layer is used in the preparation of aluminum-steel composite materials, two interfaces will appear inside the material, thereby increasing the risk of failure of the composite material. There are great differences in the thermal physical and chemical properties of aluminum and steel, which increases the difficulty of aluminum / steel dissimilar metal connection. Aluminum and steel have low mutual solubility, and are prone to generate hard and brittle intermetallic compounds (IMC) during welding, such as FeAl2, Fe2Al5 and FeAl3, which increase the brittleness of the joint; aluminum and steel have large differences in linear expansion coefficient and thermal conductivity, which are prone to produce large residual stress after welding, and are prone to crack initiation and expansion; during welding, refractory Al2O3 oxide film is easily formed on the surface of aluminum alloy, which affects the degree of fusion of weld metal and reduces welding quality. For aluminum / steel dissimilar metal connection, friction stir welding (friction stir welding) is widely used. As a solid-phase joining technology, FSW (Full Speed ​​Welding) uses the heat generated by the friction between the high-speed rotating stirring head and the workpiece and the heat generated by the deformation of the material to locally plasticize the welded material. The plasticized material flows under the stirring action of the stirring needle and forms a dense solid-phase weld under the extrusion of the welding tool. Its low heat input and short thermal cycle time can effectively control the growth of IMCs, while also reducing welding stress and defects such as cracks and pores caused by the melting-solidification process. It has become a research hotspot in the welding of aluminum / steel dissimilar materials. The FSW process has complex frictional heat generation and shear deformation behaviors. The material near the friction interface is mainly affected by the thermal-mechanical coupling provided by temperature and deformation force, causing a series of physical phenomena such as plastic deformation and flow and atomic diffusion.The large plastic deformation rate produces crystal defects such as supersaturated vacancies, dislocations and stacking faults, as well as internal stress at the interface, which reduces the activation energy of atomic diffusion and promotes the atomic diffusion kinetics. The severe plastic deformation during the stir friction treatment can refine the grains, damage the second phase particles, shorten the diffusion distance, and change the element diffusion from bulk diffusion to tube diffusion along dislocations, increasing the diffusion rate by 1000 times. Therefore, during the aluminum / steel FSW process, due to the severe plastic deformation, atoms at the interface diffuse with each other, metal bonding occurs, and a series of Fe-Al IMCs are generated to achieve aluminum / steel dissimilar metal metallurgical connection. The reliable connection of aluminum / steel dissimilar metals is closely related to the interface behavior, and the thickness and type of Fe-Al IMCs play a key role in the interface bonding. The generation of IMCs at the aluminum / steel interface can achieve metallurgical connection of aluminum / steel, which enhances the joint strength and fatigue performance compared with pure mechanical connection. However, too many IMCs will cause phase volume changes, generate local stress, and facilitate crack initiation and expansion, reducing the bearing capacity of the joint.

[0003] Therefore, defects such as cracks and pores are easily generated during the preparation process of existing aluminum-steel composite materials, which affects the mechanical properties of the material. Summary of the invention

[0004] The present invention aims to solve the above technical problems existing in the prior art. To this end, the present invention proposes an additive preparation method for aluminum-steel composite materials, which combines solid-phase additives with a variety of exogenous auxiliary process technologies to obtain a high-performance and highly reliable interface of dissimilar metal materials.

[0005] The present invention also proposes an additive manufacturing method for aluminum-steel composite materials and its application in manufacturing components in the field of transportation.

[0006] According to one aspect of the present invention, a method for additively preparing an aluminum-steel composite material is provided, comprising the following steps:

[0007] S1. performing laser preheating treatment on the aluminum alloy raw material to obtain an aluminum alloy;

[0008] S2. Aluminum alloy is added to the substrate steel plate using a stir friction additive process to obtain an aluminum-steel composite material.

[0009] The first aspect of the present invention has at least the following beneficial effects:

[0010] The invented solid-phase additive manufacturing process for aluminum-steel composite materials combines solid-phase additive with a variety of external auxiliary process technologies. The laser heat source is introduced to preheat the aluminum alloy raw materials during the stirring and rubbing additive process, which can greatly improve the softening degree of the material, improve the metal fluidity during the additive process, and reduce the heat input required during the additive process. The low heat input avoids the melting of the material during the additive process, and instead connects the metal layers through solid-phase diffusion, which can effectively avoid the generation of defects such as cracks and pores.

[0011] In some embodiments of the present invention, the preparation method further comprises: cooling the aluminum-steel composite material in step S2 at -250 to -150° C. for 20 to 120 minutes.

[0012] In some embodiments of the present invention, the preparation method further comprises: cooling the aluminum-steel composite material in step S2 at -200 to -150° C. for 20 to 120 minutes.

[0013] In some embodiments of the present invention, the cooling further includes heat treatment.

[0014] In some embodiments of the present invention, the heat treatment temperature is 150-250°C.

[0015] The additively prepared aluminum-steel composite material is placed in a coolant at a temperature of -150 to -250°C for 20 to 120 minutes, and then taken out and rapidly heated at a temperature of 150 to 250°C. The extremely cold and hot treatment can produce a large number of dislocations, strengthen the substrate, and eliminate residual stress.

[0016] In some embodiments of the present invention, the temperature of the laser preheating treatment is 200-300°C.

[0017] In some embodiments of the present invention, the laser power of the laser preheating treatment is 1 to 5 kW; the beam diameter of the laser preheating treatment is 0.5 to 1.5 mm.

[0018] In some embodiments of the present invention, the parameters of the friction stir additive process include: a rotation speed of the stirring head is 1000 to 2000 r / min.

[0019] In some embodiments of the present invention, the parameters of the friction stir additive process include: a rotation speed of the stirring head is 1000 to 2000 r / min.

[0020] In some embodiments of the present invention, the parameters of the friction stir additive process include: additive speed: 50 to 200 mm / min.

[0021] In some embodiments of the present invention, the parameters of the friction stir additive process include: additive speed: 90-110 mm / min.

[0022] In some embodiments of the present invention, the parameters of the friction stir additive process include: an inter-axial pressure of 0.5 to 2 mm.

[0023] In some embodiments of the present invention, the parameters of the friction stir additive process include: the inclination angle of the stirring head is 1 to 5 degrees

[0024] In some embodiments of the present invention, the parameters of the friction stir additive process include: the inclination angle of the stirring head is 2 to 4 degrees.

[0025] In some embodiments of the present invention, the friction stir additive process also includes ultrasonic assistance.

[0026] In some embodiments of the present invention, the ultrasonic-assisted parameters include: an ultrasonic vibration frequency of 10 to 50 kHz.

[0027] In some embodiments of the present invention, the ultrasonic-assisted parameters include: an ultrasonic vibration frequency of 20 to 40 kHz.

[0028] In some embodiments of the present invention, the ultrasonic-assisted parameters include: an amplitude of 10 to 40 μm.

[0029] In some embodiments of the present invention, the ultrasonic-assisted parameters include: an amplitude of 20 to 40 μm.

[0030] In some embodiments of the present invention, the ultrasonic-assisted parameters include: ultrasonic power of 1 to 4 kW.

[0031] In some embodiments of the present invention, the ultrasonic assistance parameters include: ultrasonic power of 2 to 4 kW.

[0032] In some embodiments of the present invention, a cooling medium is used to cool the substrate steel plate during the friction stir additive process.

[0033] In some embodiments of the present invention, the flow rate of the cooling medium is 10 to 30 L / min, and the cooling rate of the cooling medium is 10 to 30° C. / s.

[0034] In some embodiments of the present invention, the temperature of the cooling medium is 10-80°C.

[0035] In some embodiments of the present invention, the flow rate of the cooling medium is 15 to 25 L / min, and the cooling rate of the cooling medium is 15 to 25° C. / s.

[0036] The cooling medium is used to cool the base material (steel) to improve the thermal conductivity of the base material, achieve grain refinement, and improve the mechanical properties. The cooling medium can effectively reduce the welding heat input, control the growth of interface IMCs, reduce the thickness of the IMCs layer, and prevent the generation of coarse brittle compounds. Rapid cooling can improve the grain structure, thereby improving the mechanical properties of the joint.

[0037] Ultrasonic assistance and cooling medium can effectively reduce welding heat input, control the growth of interface IMCs, and rapid cooling can improve the grain structure, thereby improving the mechanical properties of the joint. Therefore, the combination of solid-phase additive manufacturing and a variety of exogenous auxiliary processes is expected to achieve low-cost, high-stability and high-quality welding / additive manufacturing of dissimilar metal materials, and obtain high-performance and high-reliability dissimilar metal material interfaces.

[0038] The present invention combines solid-phase additive manufacturing with a variety of exogenous auxiliary process technologies, and introduces laser heat sources and ultrasound during the stirring and friction additive manufacturing process, which can greatly improve the softening degree of the material and regulate the heat input. By introducing ultrasound and FSW processes simultaneously into the additive manufacturing process, on the one hand, ultrasound can cause IMCs to break and reduce the thickness of the IMCs layer; on the other hand, ultrasound introduces additional mechanical energy, which helps soften the material, reduce friction, reduce heat input, and inhibit the growth of IMCs. Solid-phase additive manufacturing under a cooling medium can reduce the stirring area and interface temperature, increase the cooling rate, and obtain ultrafine equiaxed grains. The presence of a cooling medium can quickly absorb the heat generated by stirring friction, reduce heat input, and increase the cooling rate. Less heat reduces the diffusion rate and duration between Al and Fe atoms, thereby reducing the thickness of IMCs. The faster cooling rate refines the grain structure in the weld core and significantly improves the mechanical strength of the joint.

[0039] According to a second aspect of the present invention, an additive manufacturing method for aluminum-steel composite materials and its application in manufacturing components in the field of transportation are proposed. DETAILED DESCRIPTION

[0040] The following will be combined with the embodiments to clearly and completely describe the concept of the present invention and the technical effects produced, so as to fully understand the purpose, characteristics and effects of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of the present invention.

[0041] Example 1

[0042] This embodiment provides a method for additively preparing an aluminum-steel composite material, which comprises the following steps:

[0043] S1. Use laser to preheat the 7075 aluminum alloy raw material (wherein the size of the aluminum alloy raw material is 50mm wide, 200mm long, and 6mm thick), laser power: 2kW, beam diameter: 1.0mm. Preheating temperature: 240℃;

[0044] S2. Adopting the friction stir additive process (wherein, the rotation speed of the stir head is 1000r / min, the additive speed is 100mm / min, the interaxial downward pressure is 1mm, the inclination angle of the stir head is 3°; the ultrasonic vibration frequency is 30kHz, the amplitude is 30μm, and the ultrasonic power is 3kW), 7075 aluminum alloy is added on the substrate steel plate to obtain an aluminum-steel composite material, and the aluminum-steel composite material prepared by the additive is placed in a coolant for 60min, the temperature of the coolant is -180℃, and then taken out for rapid heating, the heating temperature is 170℃, and extreme cold and extreme heat treatment is adopted;

[0045] The additive process uses coolant for cooling, and a cooling medium (the temperature of the cooling medium is 30°C) is used to cool the substrate (steel), with a flow rate of 20L / min and a cooling rate of 20°C / s.

[0046] Example 2

[0047] This embodiment provides a method for additively preparing an aluminum-steel composite material, which comprises the following steps:

[0048] S1. Preheating of 7075 aluminum alloy raw materials by laser, laser power: 2kW, beam diameter: 1.0mm.

[0049] Preheating temperature: 240℃;

[0050] S2. Adopting the friction stir additive process (wherein, the rotation speed of the stir head is 1500r / min, the additive speed is 100mm / min, the interaxial pressure is 1mm, the inclination angle of the stir head is 3°; the ultrasonic vibration frequency is 30kHz, the amplitude is 30μm, and the ultrasonic power is 3kW), 7075 aluminum alloy is added on the substrate steel plate to obtain an aluminum-steel composite material, and the aluminum-steel composite material prepared by the additive is placed in a coolant for 60min, the temperature of the coolant is -180℃, and then taken out for rapid heating, the heating temperature is 170℃, and extreme cold and extreme heat treatment is adopted;

[0051] The additive process uses coolant for cooling, and the cooling medium is used to cool the substrate (steel), with a flow rate of 20L / min and a cooling rate of 20℃ / s.

[0052] Example 3

[0053] This embodiment provides a method for additively preparing an aluminum-steel composite material, which comprises the following steps:

[0054] S1. Preheating of 7075 aluminum alloy raw materials by laser, laser power: 2kW, beam diameter: 1.0mm.

[0055] Preheating temperature: 240℃;

[0056] S2. Adopting the friction stir additive process (wherein, the rotation speed of the stir head is 2000r / min, the additive speed is 100mm / min, the downward pressure between the axes is 1mm, the inclination angle of the stir head is 3°; the ultrasonic vibration frequency is 30kHz, the amplitude is 30μm, and the ultrasonic power is 3kW), 7075 aluminum alloy is added on the substrate steel plate to obtain an aluminum-steel composite material, and the aluminum-steel composite material prepared by the additive is placed in a coolant for 60min, the temperature of the coolant is -180℃, and then taken out for rapid heating, the heating temperature is 170℃, and extreme cold and extreme heat treatment is adopted;

[0057] The additive process uses coolant for cooling, and the cooling medium is used to cool the substrate (steel), with a flow rate of 20L / min and a cooling rate of 20℃ / s.

[0058] Comparative Example 1

[0059] This comparative example provides an additive preparation method for an aluminum-steel composite material. The difference between this comparative example and Example 1 is that it does not include preheating treatment and ultrasonic assistance, and specifically includes the following steps:

[0060] S1. Using a friction stir additive process (wherein, the rotation speed of the stir head is 1000r / min, the additive speed is 100mm / min, the inter-axis downward pressure is 1mm, and the inclination angle of the stir head is 3°), 7075 aluminum alloy is added on the substrate steel plate to obtain an aluminum-steel composite material, and the aluminum-steel composite material prepared by the additive is placed in a coolant for 60 minutes, the temperature of the coolant is -180°C, and then taken out for rapid heating, the heating temperature is 170°C, and extreme cold and extreme heat treatment is adopted;

[0061] The additive process uses coolant for cooling, and the cooling medium is used to cool the substrate (steel), with a flow rate of 20L / min and a cooling rate of 20℃ / s.

[0062] Comparative Example 2

[0063] This comparative example provides an additive preparation method for an aluminum-steel composite material. The difference between this comparative example and Example 1 is that the method does not include preheating treatment and cooling in the additive step, and specifically includes the following steps:

[0064] S1. Using a friction stir additive process (wherein, the rotation speed of the stirring head is 1000r / min, the additive speed is 100mm / min, the downward pressure between the axes is 1mm, and the inclination angle of the stirring head is 3°), 7075 aluminum alloy is added on the substrate steel plate to obtain an aluminum-steel composite material, and the aluminum-steel composite material prepared by the additive is placed in a coolant for 60 minutes, the temperature of the coolant is -180°C, and then taken out and rapidly heated at a temperature of 170°C, using extremely cold and extremely hot treatment.

[0065] Comparative Example 3

[0066] This comparative example provides an additive preparation method for an aluminum-steel composite material, which specifically comprises the following steps:

[0067] S1. The 7075 aluminum alloy and the 316 stainless steel are heated to 350°C and rolled on a rolling mill with a rolling reduction of 10%;

[0068] S2. The rolled and compounded material is subjected to solution treatment at a solution temperature of 470°C and a holding time of 2h. After being taken out, it is subjected to water cooling quenching and then to aging heat treatment at 120°C / 24h.

[0069] Comparative Example 4

[0070] This comparative example provides an additive preparation method for an aluminum-steel composite material. The difference between this comparative example and Example 1 is that the laser preheating step in Example 1 is replaced, and the other conditions are the same.

[0071] This embodiment provides a method for additively preparing an aluminum-steel composite material, which comprises the following steps:

[0072] S1. Use TIG argon arc to preheat the 7075 aluminum alloy raw material, the argon arc current is 8A, and the preheating temperature is 240℃;

[0073] S2. Adopting the friction stir additive process (wherein, the rotation speed of the stir head is 1000r / min, the additive speed is 100mm / min, the interaxial downward pressure is 1mm, the inclination angle of the stir head is 3°; the ultrasonic vibration frequency is 30kHz, the amplitude is 30μm, and the ultrasonic power is 3kW), 7075 aluminum alloy is added on the substrate steel plate to obtain an aluminum-steel composite material, and the aluminum-steel composite material prepared by the additive is placed in a coolant for 60min, the temperature of the coolant is -180℃, and then taken out for rapid heating, the heating temperature is 170℃, and extreme cold and extreme heat treatment is adopted;

[0074] The additive process uses coolant for cooling, and the cooling medium is used to cool the substrate (steel), with a flow rate of 20L / min and a cooling rate of 20℃ / s.

[0075] TIG argon arc is used for preheating. Due to the low energy density of argon arc, the preheating time is long and the preheating temperature is uneven. The heat dissipation of aluminum is relatively fast, resulting in poor preheating effect, poor metal fluidity in the stirring additive process, aluminum oxide entanglement and void defects, and reduced performance. The laser energy density is large, the preheating speed is fast and uniform, and it can also remove the oxide film on the aluminum surface, so the effect is very good.

[0076] Comparative Example 5

[0077] This comparative example provides an additive preparation method for an aluminum-steel composite material. The difference between this comparative example and Example 1 is that the ultrasonic-assisted step in Example 1 is replaced, and the other conditions are the same.

[0078] S1. Preheating of 7075 aluminum alloy raw materials by laser, laser power: 2kW, beam diameter: 1.0mm.

[0079] Preheating temperature: 240℃;

[0080] S2. Adopting the friction stir additive process (wherein, the rotation speed of the stir head is 1000r / min, the additive speed is 100mm / min, the interaxial pressure is 1mm, the inclination angle of the stir head is 3°; the excitation current of the electromagnetic field is 1-10A, the frequency is 10-100Hz, and the magnetic field strength is 1-100mT), 7075 aluminum alloy is added on the substrate steel plate to obtain an aluminum-steel composite material, and the aluminum-steel composite material prepared by the additive is placed in a coolant for 60min, the temperature of the coolant is -180℃, and then taken out for rapid heating, the heating temperature is 170℃, and extreme cold and extreme heat treatment is adopted;

[0081] The additive process uses coolant for cooling, and the cooling medium is used to cool the substrate (steel), with a flow rate of 20L / min and a cooling rate of 20℃ / s.

[0082] The use of electromagnetic field has a certain material softening effect and improves fluidity, but it cannot effectively break up the coarse aluminum-iron compounds between the interfaces, nor can it hinder the formation and growth of IMCs, so the strength and shear strength are not high.

[0083] Test example

[0084] The properties of the embodiments and comparative examples are shown in Table 1.

[0085] Mechanical properties testing standard: GB / T 228.1-2021;

[0086] Table 1 Performance results

[0087]

[0088]

[0089] The invention discloses a solid-phase additive preparation technology for aluminum-steel composite materials. The solid-phase additive is combined with a variety of external auxiliary process technologies. The laser heat source is introduced into the stirring friction additive process to preheat the aluminum alloy raw material, which can well improve the softening degree of the material, improve the metal fluidity in the additive process, and reduce the heat input required in the additive process. By introducing ultrasound and FSW processes into the additive process simultaneously, on the one hand, ultrasound can cause IMCs to break, reduce the thickness of the IMCs layer, and prevent the generation of coarse brittle compounds; on the other hand, ultrasound introduces additional mechanical energy, which helps soften the material, reduce friction, reduce heat input, and inhibit the growth of IMCs. Solid-phase additive under cooling medium can reduce the stirring area and interface temperature, increase the cooling rate, and obtain ultrafine equiaxed grains. The cooling effect of steel is poor. When cooling is performed on the substrate (steel), the presence of the cooling medium can quickly absorb the heat generated by stirring friction, reduce heat input, and increase the cooling rate. Less heat reduces the diffusion rate and duration between Al and Fe atoms, thereby reducing the thickness of IMCs. The faster cooling rate refines the grain structure in the weld core and significantly improves the mechanical strength of the joint. Ultrasonic assistance and cooling medium can effectively reduce welding heat input and control the growth of interface IMCs. Rapid cooling can improve the grain structure, thereby improving the mechanical properties of the joint. Therefore, the combination of solid-phase additive and a variety of exogenous auxiliary processes is expected to achieve low-cost, high-stability and high-quality welding / additive of dissimilar metal materials, and obtain high-performance and high-reliability interfaces of dissimilar metal materials. It can be seen from the test results in Table 1 that the strength, elongation and shear strength of the composite materials prepared by combining the solid-phase additive of the present invention with a variety of exogenous auxiliary process technologies are significantly improved, the thickness of the intermetallic compound is significantly reduced, and the grain structure of the aluminum alloy of the additive is significantly refined.

[0090] Comparative Example 1 does not include preheating treatment and ultrasonic assistance, which results in reduced material fluidity, uneven deposition of aluminum alloy material during the additive process, poor molding quality, and the appearance of cracks or pores. At the same time, in the absence of ultrasonic assistance, it is impossible to reduce the plastic deformation resistance and fluidity of the metal material, and it is impossible to cause the IMCs to rupture, resulting in an increase in the thickness of the IMCs layer and the production of coarse brittle compounds.

[0091] Comparative Example 2 does not include the cooling operation in the preheating treatment and the additive step, which fails to keep the material in good fluidity, resulting in uneven fusion between layers. It also aggravates the formation of IMCs, increases the brittleness of the joint, and reduces the mechanical properties of the composite material. The cooling step is not included and the welding heat input cannot be effectively reduced, resulting in an increase in the thickness of the IMCs layer, thereby affecting the strength and shear strength.

[0092] Comparative Example 3 uses hot rolling to composite aluminum and steel, and then performs solid solution treatment. This high-temperature and long-term heat treatment method leads to the formation of thicker IMCs at the aluminum-steel interface, and the presence of a large amount of coarse and brittle aluminum-iron compounds, resulting in poor bonding performance of aluminum and steel, resulting in low strength and shear strength.

[0093] In Comparative Example 4, TIG argon arc was used for preheating. Due to the low energy density of the argon arc, the preheating time was long and the preheating temperature was uneven. The heat dissipation of aluminum was relatively fast, resulting in poor preheating effect, poor metal fluidity in the stirring additive process, aluminum oxide entrapment and void defects, and reduced performance.

[0094] In Comparative Example 5, the electromagnetic field has a certain material softening effect and improves fluidity, but it cannot effectively break up the coarse aluminum-iron compounds between the interfaces, nor can it hinder the formation and growth of IMCs, so the strength and shear strength are not high.

[0095] The above is a detailed description of the embodiments of the present invention, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the purpose of the present invention. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

Claims

1. A method for additively preparing an aluminum-steel composite material, characterized in that: The following steps are involved: S1. performing laser preheating treatment on the aluminum alloy raw material to obtain an aluminum alloy; S2. Aluminum alloy is added to the substrate steel plate using a stir friction additive process to obtain an aluminum-steel composite material.

2. The additive manufacturing method of aluminum-steel composite material according to claim 1, characterized in that: The preparation method further comprises: cooling the aluminum-steel composite material in step S2 at -250 to -150° C. for 20 to 120 minutes.

3. The additive manufacturing method of aluminum-steel composite material according to claim 2, characterized in that: The cooling step further includes heat treatment; and / or the heat treatment temperature is 150-250°C.

4. The additive manufacturing method of aluminum-steel composite material according to claim 1, characterized in that: The temperature of the laser preheating treatment is 200-300°C.

5. The additive manufacturing method of aluminum-steel composite material according to claim 1, characterized in that: The laser power of the laser preheating treatment is 1-5 kW; the beam diameter of the laser preheating treatment is 0.5-1.5 mm.

6. The additive manufacturing method of aluminum-steel composite material according to claim 1, characterized in that: The parameters of the friction stir additive process include: a rotation speed of the stirring head of 1000 to 2000 r / min; and / or; an additive speed of 50 to 200 mm / min, and / or; an inter-axial downward pressure of 0.5 to 2 mm; and / or; an inclination angle of the stirring head of 1 to 5°.

7. The additive manufacturing method of aluminum-steel composite material according to claim 1, characterized in that: The friction stir additive process also includes ultrasonic assistance; and / or, the parameters of the ultrasonic assistance include: ultrasonic vibration frequency of 10 to 50 kHz; and / or, amplitude of 10 to 40 μm; and / or, ultrasonic power of 1 to 4 kW.

8. The additive manufacturing method of aluminum-steel composite material according to claim 1, characterized in that: During the friction stir additive process, a cooling medium is used to cool the substrate steel plate.

9. The additive manufacturing method of aluminum-steel composite material according to claim 8, characterized in that: The flow rate of the cooling medium is 10 to 30 L / min, and the cooling rate of the cooling medium is 10 to 30° C. / s.

10. Use of the additive preparation method of the aluminum-steel composite material according to any one of claims 1 to 9 in the preparation of components in the field of transportation.

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