Magnesium-aluminum composite material and preparation method thereof

Abstract

The invention relates to a magnesium-aluminum composite material and a preparation method thereof, and relates to the technical field of metal-based composite materials. According to the main technical scheme, the magnesium-aluminum composite material comprises a three-dimensional continuous aluminum alloy binding phase and a steel-coated magnesium alloy bundle-shaped structure; the steel-coated magnesium alloy bundle structure comprises a plurality of bundles of steel-coated magnesium alloy structures; wherein the multiple beams of steel-coated magnesium alloy structures are distributed in the continuous aluminum alloy binding phase; and each beam of steel-coated magnesium alloy structure comprises a steel coating layer and a particle reinforced magnesium-based composite material positioned in the steel coating layer. The preparation method of the magnesium-aluminum composite material comprises the steps of material mixing, steel-magnesium composite powder core wire preparation, magnesium-aluminum composite preform preparation, rolling treatment and annealing treatment. The preparation method is mainly used for preparing the magnesium-aluminum composite material with a novel structure, so that the strength and toughness of the magnesium-aluminum composite material are improved, the magnesium-aluminum composite material has excellent toughness matching, the service life of the magnesium-aluminum composite material is greatly prolonged, and the application scene of the magnesium-aluminum composite material is greatly widened.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metal matrix composites, and particularly relates to a magnesium-aluminum composite material and a preparation method thereof. BACKGROUND

[0002] Magnesium is increasingly valued for its rich resource reserves and excellent performance of products, and has been widely used in deep processing fields such as automobiles, rail transit equipment, aerospace, military and civilian products, and the industry development prospect is very broad. However, due to the characteristics of low strength and low plasticity of magnesium, its wide application is limited. Among them, aluminum alloy has the advantages of low density, high strength, good ductility and corrosion resistance, and has a high solid solubility with magnesium. Therefore, the two metals are compounded to prepare magnesium-aluminum composite materials, which can simultaneously obtain good strength and plasticity.

[0003] The preparation process of the magnesium-aluminum composite material mainly includes hot pressing, welding, casting and rolling. It is found through research that various processes will produce continuously growing hard intermetallic compounds such as Al3Mg2 and Mg17Al12 between magnesium and aluminum elements when preparing the magnesium-aluminum composite material, which will greatly weaken the interface bonding performance of the material, thereby reducing the bonding strength of the interface. Therefore, how to improve the formation of continuously growing brittle intermetallic compounds in the interface layer of the magnesium-aluminum composite material has become a technical problem to be solved in the field. 17 Al 12 Therefore, how to improve the formation of continuously growing brittle intermetallic compounds in the interface layer of the magnesium-aluminum composite material has become a technical problem to be solved in the field.

[0004] At present, in order to inhibit the continuous growth of intermetallic compounds at the magnesium-aluminum interface, the most direct method adopted by researchers is to separate the magnesium-aluminum interface by implanting an intermediate layer to improve the defects of the continuous growth of brittle intermetallic compounds. For example, Chinese Patent 201711007352.X discloses a method for preparing aluminum / magnesium composite materials by continuous casting. A nickel-aluminum alloy is formed on the surface of the magnesium material by plasma spraying, and then aluminum melt is poured to realize the continuous casting of magnesium-aluminum composite materials in the form of Al / Mg / Al, so as to hinder the formation of hard and brittle second phases in the surface area and obtain magnesium-aluminum composite materials with good metallurgical bonding interface. In addition, Chinese Patent 202210231507.2 discloses a magnesium-aluminum layered composite plate and a preparation method thereof. The composite pipe blank is prepared by centrifugal casting, which includes: first pouring the molten liquid of aluminum alloy, treating the surface of the aluminum alloy after it cools and solidifies to obtain a nickel coating, and then pouring the molten liquid of magnesium alloy, and obtaining the composite pipe blank after cooling; the composite pipe blank is pretreated to form a composite plate; two or more composite plates of the same size are stacked and rolled in an alternating and spaced manner to obtain a magnesium-aluminum layered composite plate, wherein a nickel layer is arranged between the two adjacent composite plates to avoid the generation of a large amount of hard and brittle intermetallic compounds at the interface of the composite plate under medium-high temperature (350-500℃), thereby improving the mechanical properties of the magnesium-aluminum composite plate.

[0005] However, the above-mentioned related prior art at least has the following technical problems: (1) Since the ductile metal aluminum is not three-dimensionally continuous, it is easy to cause the whole layer to peel off and fail. (2) In order to form a nickel layer at the interface of the magnesium-aluminum composite material, surface treatment such as plasma spraying, chemical plating, electroplating or the like is required to form a nickel coating on the surface of magnesium or aluminum. However, the additional plasma spraying, chemical plating, electroplating or surface treatment process increases the overall process flow and manufacturing difficulty. (3) The introduction of the intermediate layer of the noble metal nickel significantly increases the preparation cost.

[0006] In summary, it is urgent to develop a new type of magnesium-aluminum composite material and a preparation method thereof to improve the strength and toughness of the magnesium-aluminum composite material. SUMMARY

[0007] Therefore, the present application provides a magnesium-aluminum composite material and a preparation method thereof, which mainly aims to improve a new type of magnesium-aluminum composite material to improve the strength and toughness of the magnesium-aluminum composite material.

[0008] To achieve the above-mentioned purpose, the present application mainly provides the following technical solutions:

[0009] On the one hand, the present application provides a magnesium-aluminum composite material, wherein the magnesium-aluminum composite material comprises a three-dimensionally continuous aluminum alloy binder phase and a steel-coated magnesium alloy bundle structure; wherein,

[0010] The steel-coated magnesium alloy bundle structure comprises a plurality of steel-coated magnesium alloy structures; wherein the plurality of steel-coated magnesium alloy structures are distributed in the continuous aluminum alloy binder phase.

[0011] Each of the steel-coated magnesium alloy structures comprises a steel coating layer and a particle-reinforced magnesium matrix composite located in the steel coating layer.

[0012] Preferably, the steel coating layer is a low-carbon steel coating layer; preferably, the steel coating layer is an H08A low-carbon steel coating layer.

[0013] Preferably, the particle-reinforced magnesium matrix composite comprises a magnesium alloy binder phase and a particle-reinforced phase distributed in the magnesium alloy binder phase; preferably, the particle-reinforced phase is one or more of metal Ti particles, SiC particles, and TiC particles.

[0014] Preferably, in the magnesium-aluminum composite, the volume fraction of steel is 4-15%, the volume fraction of the particle-reinforced magnesium matrix composite is 15-55%, and the volume fraction of aluminum is 30-81%.

[0015] Preferably, in the magnesium-aluminum composite: an A15Fe2 and Al4 gradient transition layer is formed at the interface between the steel coating layer and the continuous aluminum alloy binder phase; and / or when the particle-reinforced magnesium matrix composite contains aluminum elements, an A15Fe2 gradient layer is formed at the interface between the steel coating layer and the particle-reinforced magnesium matrix composite. 13

[0016] Preferably, the magnesium-aluminum composite has a tensile strength of 343-427 MPa, an elongation of 7.5-15.2%, and an impact energy of 13-28 J.

[0017] Preferably, the method for preparing the magnesium-aluminum composite comprises the following steps:

[0018] Mixing step: ball-milling and mixing magnesium alloy powder and reinforcing particles to obtain particle-reinforced magnesium alloy powder;

[0019] Preparation of steel-magnesium composite powder core wire step: placing the particle-reinforced magnesium alloy powder into a steel structure with a containing cavity, processing into a wire, and obtaining a steel-magnesium composite powder core wire with a steel coating layer and a particle-reinforced magnesium alloy powder core layer;

[0020] ​The step of preparing the magnesium-aluminum composite preform comprises the following steps: cladding aluminum alloy on an aluminum alloy substrate to obtain a first aluminum alloy layer; laying the steel-magnesium composite powder core wire on the first aluminum alloy layer to obtain a first wire layer; cladding aluminum alloy on the first aluminum alloy layer and the first wire layer to obtain a second aluminum alloy layer; repeating the steps of laying the steel-magnesium composite powder core wire and cladding aluminum alloy for 0 times or at least one time to obtain the magnesium-aluminum composite preform.

[0021] The step of rolling treatment comprises the following steps: rolling the magnesium-aluminum composite preform to obtain a rolled magnesium-aluminum composite preform.

[0022] The step of annealing treatment comprises the following steps: annealing the rolled magnesium-aluminum composite preform to obtain the magnesium-aluminum composite material.

[0023] Preferably, in the mixing step, the particulate reinforced magnesium alloy powder comprises 85-98% of magnesium alloy powder and 2-15% of reinforcing particles by weight percentage; preferably, the magnesium alloy powder has a particle size of 5-15 μm; and preferably, the reinforcing particles have a particle size of 100 nm-55 μm.

[0024] Preferably, the process parameters of the ball milling mixing are as follows: the ball-to-material ratio is 15:1-20:1, the rotation speed of the ball mill is 200-500 r / min, and the diameter of the grinding ball is 3-10 mm.

[0025] Preferably, during the ball milling mixing process, the intermittent ball milling mixing method is adopted, the time for each continuous ball milling mixing process is 20-40 min, and the interval time is 10-15 min; and the total time for the ball milling mixing process is 8-10 h.

[0026] Preferably, in the step of preparing the steel-magnesium composite powder core wire, the steel structure with the accommodating cavity is a steel strip structure with the accommodating cavity; preferably, the steel strip is rolled into the steel strip structure with the accommodating cavity; further preferably, the width of the steel strip is 4-12 mm, and the thickness of the steel strip is 0.05-0.2 mm; preferably, the cross section of the steel strip structure with the accommodating cavity is in a U shape; and / or the composition of the steel structure with the accommodating cavity is low-carbon steel, preferably H08A low-carbon steel; and / or the outer diameter D of the steel-magnesium composite powder core wire is 1-3 mm.

[0027] Preferably, in the step of preparing the magnesium-aluminum composite preform: an aluminum alloy layer is prepared using arc additive manufacturing technology; preferably, the step of preparing the aluminum alloy layer using arc additive manufacturing technology includes: loading aluminum alloy welding wire into a wire feeder, melting it into a molten state through a welding torch and spraying it onto the substrate to form an aluminum alloy layer; wherein, the substrate is one or more of aluminum alloy substrate, steel-magnesium composite core wire, and aluminum alloy layer; preferably, the wire feeding speed of the wire feeder is 500-650 mm / min, the movement speed of the welding torch is 90-110 mm / min, the current is 50-100 A, and the shielding gas flow rate is 10-20 L / min; more preferably, argon is used as the shielding gas.

[0028] Preferably, in the step of preparing the magnesium-aluminum composite preform: the thickness of the first aluminum alloy layer is 2-4 mm; and / or the thickness of the second aluminum alloy layer is 0.5D-1.5D; wherein, D is the outer diameter of the steel-magnesium composite core wire in mm; and / or when laying the steel-magnesium composite core wire, the steel-magnesium composite core wire must be laid in parallel, and the wire spacing is 1-3 mm.

[0029] Preferably, in the rolling process: the rolling temperature is 430-500℃, the holding time is 15-50 min, and the total rolling deformation is 25-45%; and / or in the annealing process: the annealing temperature is 200-350℃, and the annealing time is 20-60 min.

[0030] Compared with the prior art, the magnesium-aluminum composite material and its preparation method of the present invention have at least the following beneficial effects:

[0031] On one hand, embodiments of the present invention provide a magnesium-aluminum composite material, which includes a three-dimensional continuous aluminum alloy binder phase and a steel-clad magnesium alloy bundle structure; wherein, the steel-clad magnesium alloy bundle structure includes multiple steel-clad magnesium alloy structures; wherein, the multiple steel-clad magnesium alloy structures are distributed in the three-dimensional continuous aluminum alloy binder phase; each steel-clad magnesium alloy structure includes a steel cladding layer and a particle-reinforced magnesium matrix composite material located within the steel cladding layer. Regarding the magnesium-aluminum composite material with the above structure, the following points are explained: First, the present invention utilizes hard particles in the core layer to reinforce the magnesium matrix composite material, thereby improving the overall strength of the composite material; Second, the present invention, with the help of a high-toughness low-carbon steel cladding layer, effectively inhibits the interfacial reaction between metallic magnesium and metallic aluminum, and effectively inhibits the crack initiation, propagation, and passivation of the hard particles in the core layer reinforced magnesium matrix composite material, thus significantly improving the damage tolerance of the composite material; Third, based on the in-situ reaction principle and element interdiffusion behavior, Al₂₅Fe₂ and Al₂₃Fe₂ are formed at the interface between low-carbon steel and aluminum. 13An Fe4 gradient transition layer is formed at the interface between the magnesium alloy and carbon steel when the magnesium alloy contains Al. Therefore, the low-carbon steel cladding layer effectively connects the core-layer hard particle-reinforced magnesium matrix composite with the high-strength, high-toughness aluminum alloy bonding phase. Simultaneously, the formation of the interface gradient layer effectively reduces macroscopic interface stress concentration, improves load transfer efficiency, and helps the composite material achieve a superior strength-toughness balance. Therefore, the solution of this invention improves the strength and toughness of magnesium-aluminum composite materials, exhibiting excellent strength-toughness matching.

[0032] On the other hand, embodiments of the present invention provide a method for preparing the above-mentioned magnesium-aluminum composite material, comprising the following steps: a mixing step: ball milling and mixing magnesium alloy powder and reinforcing particles to obtain particle-reinforced magnesium alloy powder; a steel-magnesium composite powder core wire preparation step: placing the particle-reinforced magnesium alloy powder into a steel structure with a accommodating cavity and processing it into wire to obtain a steel-magnesium composite powder core wire with steel as the cladding layer and particle-reinforced magnesium alloy powder as the core layer; a magnesium-aluminum composite preform preparation step: cladding aluminum alloy onto an aluminum alloy substrate to obtain a first aluminum alloy layer; in the first... The steel-magnesium composite core wire is laid on the aluminum alloy layer to obtain a first wire layer; aluminum alloy is clad on the first aluminum alloy layer and the first wire layer to obtain a second aluminum alloy layer; the steps of laying the steel-magnesium composite core wire and cladding the aluminum alloy are repeated 0 times or at least once (once or more) to obtain a magnesium-aluminum composite preform; a rolling process is performed to roll the magnesium-aluminum composite preform to obtain a rolled magnesium-aluminum composite preform; an annealing process is performed to anneal the rolled magnesium-aluminum composite preform to obtain the magnesium-aluminum composite material. Here, the above preparation method is explained as follows: First, the present invention achieves the preparation of the desired magnesium-aluminum composite material through the above preparation method; Second, the present invention can control the composition of the magnesium alloy core by preparing the steel-magnesium composite core wire, and can also control the diameter and wall thickness of the composite core wire by drawing and diameter reduction; Third, the present invention uses electric arc additive manufacturing to prepare the aluminum alloy layer. During the preparation process, the wire spacing and distribution can be precisely controlled, and the thickness of the aluminum alloy layer can also be precisely controlled. In addition, the use of high-temperature electric arc helps to form a metallurgical bonding interface. Fourth, this invention, prepared by electric arc additive manufacturing and hot rolling technology, significantly improves the strength, ductility, and wear resistance of magnesium-aluminum composite materials. The tensile strength is 343-427 MPa and the elongation is 7.5-15.2%, which are 10-124% and 56-192% higher than those of metallic magnesium (120 MPa and 6.8%), respectively. The impact energy is 13-28 J, which is 46-215% higher than that of metallic magnesium (8.9 J), greatly improving the service life and application scenarios of magnesium-aluminum composite materials.

[0033] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the structure of a magnesium-aluminum composite material provided in an embodiment of the present invention;

[0035] Figure 2 This is a schematic diagram of each steel-clad magnesium alloy structure according to an embodiment of the present invention;

[0036] Figure 3 This is a flowchart illustrating the preparation process of a magnesium-aluminum composite material, as provided in an embodiment of the present invention.

[0037] Figure 4 This is a physical image of a magnesium-aluminum composite material prepared according to an embodiment of the present invention (made from steel-magnesium composite core wire with a diameter of 3 mm);

[0038] Figure 5 This is a physical image of a magnesium-aluminum composite material prepared according to an embodiment of the present invention (made from steel-magnesium composite powder core wire with a diameter of 2 mm);

[0039] Figure 6 This is a microstructure diagram of the aluminum / steel interface in the magnesium-aluminum composite material prepared according to the embodiments of the present invention;

[0040] Figure 7 This is a microstructure diagram of the steel-magnesium alloy interface in the magnesium-aluminum composite material prepared according to an embodiment of the present invention;

[0041] Figure 8 This is a phase analysis diagram of the magnesium-aluminum composite material prepared according to an embodiment of the present invention;

[0042] Figure 9 This is a flowchart illustrating the preparation of steel-magnesium composite powder core wire according to an embodiment of the present invention. Detailed Implementation

[0043] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the specific embodiments, structures, features, and effects according to the present invention will be described in detail below with reference to the accompanying drawings and preferred embodiments. In the following description, different "embodiments" or "embodiments" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0044] On the one hand, embodiments of the present invention provide a magnesium-aluminum composite material, such as... Figure 1 and Figure 2As shown, the steel-clad magnesium alloy bundle structure includes multiple bundles of steel-clad magnesium alloy structures 1 (see...). Figure 1 As shown, the structure presents a bundled structure in the vertical direction, with each bundle being a steel-clad magnesium alloy structure; wherein, multiple bundles of steel-clad magnesium alloy structures 1 are distributed in a three-dimensional continuous aluminum alloy binder phase 2. Each bundle of steel-clad magnesium alloy structure 1 includes a steel cladding layer 3 and a particle-reinforced magnesium matrix composite material 4 located within the steel cladding layer 3.

[0045] Preferably, the steel cladding layer 3 is a high-toughness low-carbon steel cladding layer; more preferably, the steel cladding layer 3 is an H08A low-carbon steel cladding layer.

[0046] Preferably, the particle-reinforced magnesium matrix composite material includes a magnesium alloy binder phase 5 and a particle-reinforcing phase 6 distributed within the magnesium alloy binder phase. Preferably, the particle-reinforcing phase is one or more of metallic Ti particles, SiC particles, and TiC particles. The magnesium alloy is AZ31, AZ91, AM60B, ZK61M, etc. The particle-reinforced magnesium matrix composite material includes 85-98 wt% of the magnesium alloy binder phase and 2-15 wt% of the reinforcing particle phase.

[0047] Preferably, in the magnesium-aluminum composite material, Al₂O₅Fe₂ and Al₂O₃ are formed at the interface between the steel cladding layer 3 and the continuous aluminum alloy binder phase 2. 13 Fe4 gradient transition layer (see Fe4 gradient transition layer) Figure 6 Here, "gradient" refers to a gradient in composition and volume fraction. When the particle-reinforced magnesium matrix composite contains aluminum, an Al₅Fe₂ gradient layer is formed at the interface between the steel cladding layer 3 and the particle-reinforced magnesium matrix composite (see...). Figure 7 Here, "gradient" refers to a gradient in composition and volume fraction. Multiple bundles of steel-clad magnesium alloy structures are distributed in parallel within the continuous aluminum alloy binder phase.

[0048] Preferably, in the magnesium-aluminum composite material, the volume fraction of steel is 4-15%, the volume fraction of particle-reinforced magnesium matrix composite material is 15-55%, and the volume fraction of aluminum is 30-81%.

[0049] On the other hand, the present invention provides a method for preparing the above-mentioned magnesium-aluminum composite material, the raw materials used are as follows: magnesium alloy powder (particle size of 5-15μm, purity of 99.9%, such as AZ31, AZ91, etc.), reinforcing particles (hard particles, such as one or more of metallic Ti particles, SiC particles, TiC particles, etc., ceramic particles with a particle size of about 100nm-55μm), high-toughness low-carbon steel (the width of the high-toughness low-carbon steel strip is 4-12mm, and the thickness is 0.05-0.2mm), aluminum alloy welding wire (such as 4-series aluminum alloy welding wire or 5-series aluminum alloy welding wire; further, for example, ER1070, ER3103, ER4043, ER5356, but not limited thereto).

[0050] Among them, such as Figure 3 and Figure 9 As shown, the preparation method includes the following steps:

[0051] Mixing step: The magnesium alloy powder and reinforcing particles (also known as hard particles) are ball-milled and mixed to obtain particle-reinforced magnesium alloy powder.

[0052] Preferably, the procedure is as follows: Weigh the following components by mass percentage: 85-98% magnesium alloy powder and 2-15% reinforcing particles, with the total weight percentage of all components being 100%. Mix the materials using a planetary ball mill, with a ball-to-material ratio of 15:1-20:1. Set the mill speed to 200-500 r / min and the grinding ball diameter to 3-10 mm. To prevent excessively high milling temperatures and ball / tank sticking, intermittent ball milling is used. Each continuous ball milling process takes 20-40 minutes, with an interval of 10-15 minutes, for a total ball milling time of 8-10 hours.

[0053] Steps for preparing steel-magnesium composite powder core wire: The particle-reinforced magnesium alloy powder is placed in a steel structure with a accommodating cavity, and after being encapsulated and rolled, it is processed into wire to obtain a steel-magnesium composite powder core wire with steel as the cladding layer and particle-reinforced magnesium alloy powder as the core layer.

[0054] Preferably, the steel structure is mainly low-carbon steel (carbon content less than 0.25%), preferably high-toughness low-carbon steel strip (high toughness to ensure it can be made into wire); more preferably H08A.

[0055] Preferably, in this step, a low-carbon steel strip with a width of 4-12 mm and a thickness of 0.05-0.2 mm is rolled into a U-shaped steel strip (see schematic diagram of the U-shaped steel strip for details). Figure 9 As shown, the cross-section is U-shaped; the U-shaped steel strip is a steel structure with a cavity, but it is not limited to this, and a steel pipe structure can also be used as a steel structure with a cavity. The particle-reinforced magnesium alloy powder is then placed into the U-shaped steel strip, the U-shaped steel strip is encapsulated and rolled, and finally a steel-magnesium composite powder core wire with an outer diameter D of 1-3 mm is obtained through drawing and diameter reduction processes.

[0056] The steps for preparing the magnesium-aluminum composite preform are as follows: Aluminum alloy is clad onto an aluminum alloy substrate to obtain a first aluminum alloy layer; the steel-magnesium composite core wire is laid on the first aluminum alloy layer to obtain a first wire layer; aluminum alloy is clad onto the first aluminum alloy layer and the first wire layer to obtain a second aluminum alloy layer; the steps of laying the steel-magnesium composite core wire and cladding the aluminum alloy are repeated 0 times or at least once to obtain the magnesium-aluminum composite preform. Preferably, the laying direction of all wire layers is consistent. Preferably, the steel-magnesium composite core wires in the same wire layer are laid in parallel (the spacing between the wires is 1-3 mm). Preferably, the thickness of the first aluminum alloy layer is 2-4 mm; the thickness of the remaining aluminum alloy layers is 0.5D-1.5D mm, where D is the outer diameter of the steel-magnesium composite core wire in mm.

[0057] Preferably, in this step, an arc additive manufacturing technology is used to prepare a magnesium-aluminum composite material on an aluminum alloy substrate, specifically as follows: An aluminum alloy welding wire is loaded into a wire feeder and melted into a molten state by a welding torch, then sprayed onto the aluminum alloy substrate. A wire feeding auxiliary device is installed on the robotic arm at the end of the welding torch and moves synchronously with the welding torch. The wire feeding speed of the wire feeder is 500-650 mm / min, the movement speed of the welding torch is 90-110 mm / min, the current is 50-100 A, and the flow rate of pure argon shielding gas is 10-20 L / min. First, an aluminum alloy layer with a thickness of 2-4 mm (first aluminum alloy layer) is uniformly clad onto the aluminum alloy substrate. Then, steel-magnesium composite cored wires are laid parallel on the first aluminum alloy layer with a wire spacing of 1-3 mm (first layer of steel-magnesium composite cored wires). Subsequently, an aluminum alloy layer with a thickness of 1D-1.5D mm (second aluminum alloy layer) is uniformly clad onto its surface. Preferably, a steel-magnesium composite powder core wire (second layer steel-magnesium composite powder core wire) is laid parallel to the surface of the second aluminum alloy layer, and its direction is consistent with that of the first layer steel-magnesium composite powder core wire. Then, an aluminum alloy layer (third layer) with a thickness of 1D-1.5D mm is uniformly clad onto its surface. This process is repeated alternately to obtain the magnesium-aluminum composite preform. The number of cladding layers can be adjusted according to the workpiece requirements. During the cladding process, diffusion occurs between the molten aluminum alloy and the low-carbon steel to form Al₂O₃ and Al₂O₃. 13 A Fe4 gradient transition layer is formed, thereby obtaining a metallurgical bonding interface.

[0058] The rolling process involves rolling the magnesium-aluminum composite preform to obtain the rolled magnesium-aluminum composite preform.

[0059] Among them, hot-rolled magnesium-aluminum composite material is obtained by hot rolling of magnesium-aluminum composite preforms. The rolling temperature is 430-500℃, the holding time is 15-50min, and the total deformation during hot rolling is 25-45%. During the hot rolling process, the steel-magnesium composite core wire in the magnesium-aluminum composite preform is densified to form a steel-magnesium composite bundle structure, and the microstructure (magnesium alloy and aluminum alloy matrix structure) is refined.

[0060] Annealing treatment: The rolled magnesium-aluminum composite preform is annealed to obtain the magnesium-aluminum composite material.

[0061] In this process, the rolled magnesium-aluminum composite preform is annealed to prepare a high-strength and high-toughness magnesium-aluminum composite material. The heat treatment temperature is 200-350℃ and the heat treatment time is 20-60min.

[0062] The following explanation is needed regarding the above-mentioned solution of the present invention:

[0063] 1. Regarding the structure and interfacial reaction inhibition mechanism of the magnesium-aluminum composite material in the embodiments of the present invention.

[0064] Structure: The design consists of steel-clad magnesium alloy bundles uniformly distributed within a three-dimensional continuous aluminum alloy binder phase. Each bundle comprises an outer steel cladding layer and a core layer of particle-reinforced magnesium matrix composite material, with a gradient structure at the interface between the steel cladding layer and the core layer.

[0065] Interface reaction inhibition mechanism: In this embodiment of the invention, a steel cladding layer is used as a physical barrier to isolate the magnesium alloy and aluminum alloy, preventing direct contact between Mg and Al. An Fe-Al gradient transition layer (Al₂O₅Fe₂ / Al₃O₃) is formed through an in-situ reaction. 13 Fe4) helps alleviate stress concentration.

[0066] It should be noted that the steel cladding completely isolates magnesium / aluminum from contact, thoroughly inhibiting Al3Mg2 and Mg. 17 Al 12 Brittle intermetallic compounds are formed. Traditional magnesium-aluminum composites require an additional nickel interlayer (such as plasma spraying), while this invention achieves this in one step through a steel cladding layer, simplifying the process and reducing costs.

[0067] The solution of this invention achieves a synergistic improvement in strength and toughness. ① Strengthening mechanism: The core layer is a particle-reinforced magnesium-based composite material, which improves the overall strength; at the same time, an excellent gradient interface (Al5Fe2 and Al2Fe2 are formed at the interface between the steel cladding layer 3 and the continuous aluminum alloy binder phase 2) 13 The Fe4 gradient transition layer can improve load transfer efficiency and achieve load transfer strengthening. ② Toughening mechanism: The outer layer is a three-dimensional continuous aluminum alloy, which can provide high toughness and ductility; at the same time, the steel cladding layer can passivate cracks and prevent their propagation.

[0068] 2. Key processes of the present invention:

[0069] ① Steel-magnesium composite powder core wire: Granular reinforced magnesium alloy powder is encapsulated in a steel structure and drawn into a composite wire. This not only allows for the control of the composition of the core layer in the composite wire, but also the control of the diameter of the composite wire and the relative proportion between the steel cladding layer and the core layer.

[0070] ② Arc additive manufacturing: Precisely control the spacing of composite wires and the thickness of aluminum alloy layers, and achieve metallurgical bonding between the steel cladding layer and metallic aluminum.

[0071] ③ Hot rolling + annealing: to achieve densification of the core layer particle-reinforced magnesium matrix composite material and to form a metallurgical bonding interface between the low carbon steel cladding layer and the core layer.

[0072] 3. The preparation process of this invention has significant advantages:

[0073] ① Precise structural control: Arc additive manufacturing enables precise control of wire spacing (1–3 mm) and aluminum alloy layer thickness, avoiding the interlayer misalignment problem of traditional lamination processes.

[0074] ② High-efficiency metallurgical bonding: High-temperature electric arc melting promotes the in-situ formation of a gradient transition layer at the steel / aluminum interface, which, combined with hot rolling densification, enhances the interfacial bonding strength.

[0075] ③ Cost reduction: Eliminating the precious metal nickel intermediate layer and complex surface treatments such as electroplating / spraying simplifies the process by more than 30%.

[0076] 4. Breaking through the limitations of traditional composite materials.

[0077] The three-dimensional continuous aluminum alloy matrix of this invention avoids the risk of "whole-layer peeling" failure caused by discontinuous aluminum layers in the prior art. This invention achieves multi-scale reinforcement, namely the synergistic effect of the steel cladding layer (macroscopic) and the core layer hard particles (microscopic), to achieve a composite structure that combines rigidity and flexibility.

[0078] The solution of this invention and its beneficial effects are shown in the table below:

[0079]

[0080] Here, the innovative design of "using steel to separate magnesium and aluminum, using particles to strengthen magnesium matrix, and using gradient interface to adjust stress" proposed in this embodiment of the invention breaks through the bottleneck of the difficulty in achieving both strength and toughness in magnesium-aluminum composite materials, and provides a high-performance solution for lightweight structural materials.

[0081] 5. Regarding the Al₅Fe₂ and Al₂ of this invention 13 The process determining factors for the formation of the Fe4 gradient transition layer.

[0082] The formation of the gradient layer depends on diffusion kinetics control; key process parameters are shown in the table below.

[0083]

[0084] A15Fe2 and A1 13 Key mechanism of Fe4 gradient transition layer formation:

[0085] A15Fe2 preferentially forms on the steel side, is rich in Fe (Fe:Al≈1:2.5), has high hardness, but thin layers can withstand stress. 13 Fe4: Formed on the aluminum side, rich in Al (Fe:Al≈1:3.25), with good toughness.

[0086] Gradient transition: By controlling the heat input and time, the volume fraction of the two phases is adjusted from the steel side (mainly Al15Fe2) to the aluminum side (Al2). 13 The continuous transition (mainly Fe4) forms a stress buffer zone.

[0087] In addition, A15Fe2 and A1 13 The core function of the Fe4 gradient transition layer is shown in the table below:

[0088]

[0089] In summary, the synergistic strengthening pathways of the present invention are as follows: ① Particle-reinforced magnesium matrix: Ti / SiC / TiC particles play a role in dispersion strengthening and dislocation pinning; ② Steel cladding layer constraint: suppresses magnesium matrix cracks and improves damage tolerance; ③ Dual-gradient interface layer: improves load transfer efficiency; ④ Three-dimensional continuous aluminum alloy: provides toughness support and improves overall plasticity.

[0090] The present invention will be further described below through specific embodiments. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0091] Example 1

[0092] This embodiment prepares a magnesium-aluminum composite material, wherein the raw materials used are as follows: AZ31 magnesium alloy powder, TiC powder, low carbon steel, and aluminum alloy welding wire. The AZ31 magnesium alloy powder has a particle size of 5-15 μm and a purity of 99.9%. The TiC particles have a particle size of approximately 3-15 μm. The low carbon steel strip (H08A) has a width of 5 mm and a thickness of 0.08 mm. The aluminum alloy welding wire is ER4043 aluminum alloy welding wire.

[0093] The main steps include the following:

[0094] Mixing steps: Weigh the following components by mass percentage: 90% magnesium alloy powder and 10% reinforcing TiC particles. A planetary ball mill is used for mixing, with a ball-to-powder ratio of 20:1. The mill speed is set to 200 r / min, and the grinding ball diameter is 3-10 mm. To prevent excessive ball milling temperature and subsequent ball sticking, intermittent ball milling is used in this experiment. Each continuous ball milling session lasts 20 min, with a 10 min interval, for a total ball milling time of 8 h.

[0095] The steps for preparing steel-magnesium composite powder core wire are as follows: a low-carbon steel strip with a width of 5 mm and a thickness of 0.05 mm is rolled into a U-shaped steel strip, then the mixed powder is placed into the U-shaped steel strip, the U-shaped steel strip is sealed and rolled, and finally steel-magnesium composite powder core wire with an outer diameter D of 1 mm is obtained through drawing and diameter reduction processes.

[0096] The steps for preparing the magnesium-aluminum composite preform are as follows: Magnesium-aluminum composite materials are prepared on an aluminum alloy substrate using arc additive manufacturing technology. Specifically, aluminum alloy welding wire is loaded into a wire feeder and melted into a molten state by a welding torch, then sprayed onto the aluminum alloy substrate. A wire feeding auxiliary device is installed on the robotic arm at the end of the welding torch and moves synchronously with the torch. The wire feeding speed of the wire feeder is 650 mm / min, the movement speed of the welding torch is 100 mm / min, the current is 70 A, and the pure argon shielding gas flow rate is 15 L / min. First, an aluminum alloy layer with a thickness of approximately 2 mm (first aluminum alloy layer) is uniformly clad onto the aluminum alloy substrate. Then, steel-magnesium composite cored wires are laid parallel to the first aluminum alloy layer, with a wire spacing of 1 mm (first wire layer). Finally, an aluminum alloy layer with a thickness of 1 mm (second aluminum alloy layer) is uniformly clad onto the surfaces of the first aluminum alloy layer and the first wire layer. Then, steel-magnesium composite powder core wire (second wire layer) is laid parallel to the surface of the second aluminum alloy layer; wherein the direction of the second wire layer is consistent with that of the first wire layer. Subsequently, an aluminum alloy layer with a thickness of 1 mm (third aluminum alloy layer) is uniformly clad onto the surfaces of the second aluminum alloy layer and the second wire layer. The above steps are repeated alternately to obtain the magnesium-aluminum composite preform; wherein the total number of aluminum alloy cladding layers is 15. During the cladding process, diffusion occurs between the molten aluminum alloy liquid and the low carbon steel to form Al5Fe2 and Al2O3. 13 An Fe4 gradient transition layer is formed, thereby achieving a metallurgical bonding interface. An Al5Fe2 gradient layer is formed at the interface between low-carbon steel and particulate-reinforced magnesium matrix composites.

[0097] The rolling process involves rolling the magnesium-aluminum composite preform to obtain a rolled magnesium-aluminum composite preform. The rolling temperature is 450℃, the holding time is 15 minutes, and the total rolling deformation is 25%. During the rolling process, the steel-magnesium composite core wire in the magnesium-aluminum composite preform is densified, forming a steel-magnesium composite bundle structure, while the microstructure is refined.

[0098] Annealing treatment is performed on the rolled magnesium-aluminum composite preform to obtain the magnesium-aluminum composite material. The heat treatment temperature is 200℃, and the heat treatment time is 20 minutes.

[0099] In the magnesium-aluminum composite material prepared in this embodiment, the volume fraction of steel is 5%, the volume fraction of particle-reinforced magnesium matrix composite material is 16%, and the volume fraction of aluminum is 79%.

[0100] Example 2

[0101] This embodiment prepares a magnesium-aluminum composite material, wherein the raw materials used are as follows: AZ31 magnesium alloy powder, Ti powder, low carbon steel, and aluminum alloy welding wire. The AZ31 magnesium alloy powder has a particle size of 5-15 μm and a purity of 99.9%. The Ti particles have a particle size of approximately 0.5-9 μm. The low carbon steel strip (H08A) has a width of 6 mm and a thickness of 0.2 mm. The aluminum alloy welding wire is ER4043 aluminum alloy welding wire.

[0102] The main steps include the following:

[0103] Mixing steps: Weigh the following components by mass percentage: 95% magnesium alloy powder and 5% reinforcing Ti particles. A planetary ball mill is used for mixing, with a ball-to-powder ratio of 20:1. The mill speed is set to 300 r / min, and the grinding ball diameter is 3-10 mm. To prevent excessive ball milling temperature and subsequent ball sticking, intermittent ball milling is used in this experiment. Each continuous ball milling session lasts 30 min, with a 15 min interval between sessions, for a total ball milling time of 8 h.

[0104] The steps for preparing steel-magnesium composite powder core wire are as follows: a low-carbon steel strip with a width of 6 mm and a thickness of 0.2 mm is rolled into a U-shaped steel strip, then the mixed powder is placed into the U-shaped steel strip, the U-shaped steel strip is sealed and rolled, and finally steel-magnesium composite powder core wire with an outer diameter D of 1.5 mm is obtained through drawing and diameter reduction processes.

[0105] The steps for preparing the magnesium-aluminum composite preform are as follows: Magnesium-aluminum composite materials are prepared on an aluminum alloy substrate using arc additive manufacturing technology. Specifically, aluminum alloy welding wire is loaded into a wire feeder and melted into a molten state by a welding torch, then sprayed onto the aluminum alloy substrate. A wire feeding auxiliary device is installed on the robotic arm at the end of the welding torch and moves synchronously with the torch. The wire feeding speed of the wire feeder is 500 mm / min, the movement speed of the welding torch is 100 mm / min, the current is 70 A, and the pure argon shielding gas flow rate is 15 L / min. First, a layer of aluminum alloy with a thickness of approximately 2 mm (first aluminum alloy layer) is uniformly clad onto the aluminum alloy substrate. Then, steel-magnesium composite cored wires are laid parallel to the first aluminum alloy layer, with a wire spacing of 2 mm (first wire layer). Finally, a layer of aluminum alloy with a thickness of 1.8 mm (second aluminum alloy layer) is uniformly clad onto the surfaces of the first aluminum alloy layer and the first wire layer. Then, steel-magnesium composite powder core wire (second wire layer) is laid parallel to the surface of the second aluminum alloy layer; wherein the direction of the second wire layer is consistent with that of the first wire layer. Subsequently, an aluminum alloy layer with a thickness of 1.8 mm (third aluminum alloy layer) is uniformly clad onto the surfaces of the second aluminum alloy layer and the second wire layer. This process is repeated alternately to obtain the magnesium-aluminum composite preform. The total number of aluminum alloy cladding layers is 10. During the cladding process, diffusion occurs between the molten aluminum alloy and the low-carbon steel to form Al₂O₃ and Al₂O₃. 13 An Fe4 gradient transition layer is formed, thereby achieving a metallurgical bonding interface. An Al5Fe2 gradient layer is formed at the interface between low-carbon steel and particulate-reinforced magnesium matrix composites.

[0106] The rolling process involves rolling the magnesium-aluminum composite preform to obtain a rolled magnesium-aluminum composite preform. The rolling temperature is 450℃, the holding time is 20 minutes, and the total rolling deformation is 35%. During the rolling process, the steel-magnesium composite core wire in the magnesium-aluminum composite preform is densified, forming a steel-magnesium composite bundle structure, while the microstructure is refined.

[0107] Annealing treatment is performed on the rolled magnesium-aluminum composite preform to obtain the magnesium-aluminum composite material. The heat treatment temperature is 300℃, and the heat treatment time is 30 minutes.

[0108] In the magnesium-aluminum composite material prepared in this embodiment, the volume fraction of steel is 8%, the volume fraction of particle-reinforced magnesium matrix composite material is 15%, and the volume fraction of aluminum is 77%.

[0109] Example 3

[0110] This embodiment prepares a magnesium-aluminum composite material, wherein the raw materials used are as follows: AZ91 magnesium alloy powder, Ti powder, low carbon steel, and aluminum alloy welding wire. The AZ91 magnesium alloy powder has a particle size of 5-15 μm and a purity of 99.9%. The Ti particles have a particle size of approximately 100 nm-9 μm. The low carbon steel strip (H08A) has a width of 8 mm and a thickness of 0.2 mm. The aluminum alloy welding wire is ER4043 aluminum alloy welding wire.

[0111] The main steps include the following:

[0112] Mixing steps: Weigh the following components by mass percentage: 95% magnesium alloy powder and 5% reinforcing Ti particles. A planetary ball mill was used for mixing, with a ball-to-powder ratio of 20:1. The mill speed was set to 300 r / min, and the grinding ball diameter was 3-10 mm. To prevent excessive ball milling temperature and subsequent ball sticking, intermittent ball milling was used in this experiment. Each continuous ball milling session lasted 40 min, with a 15 min interval, for a total ball milling time of 9 h.

[0113] The steps for preparing steel-magnesium composite powder core wire are as follows: a low-carbon steel strip with a width of 8 mm and a thickness of 0.2 mm is rolled into a U-shaped steel strip, then the mixed powder is placed into the U-shaped steel strip, the U-shaped steel strip is sealed and rolled, and finally steel-magnesium composite powder core wire with an outer diameter D of 2 mm is obtained through drawing and diameter reduction processes.

[0114] The steps for preparing the magnesium-aluminum composite preform are as follows: Magnesium-aluminum composite materials are prepared on an aluminum alloy substrate using arc additive manufacturing technology. Specifically, aluminum alloy welding wire is loaded into a wire feeder and melted into a molten state by a welding torch, then sprayed onto the aluminum alloy substrate. A wire feeding auxiliary device is installed on the robotic arm at the end of the welding torch and moves synchronously with the torch. The wire feeding speed of the wire feeder is 500 mm / min, the movement speed of the welding torch is 100 mm / min, the current is 90 A, and the pure argon shielding gas flow rate is 15 L / min. First, a layer of aluminum alloy with a thickness of approximately 2 mm (first aluminum alloy layer) is uniformly clad onto the aluminum alloy substrate. Then, steel-magnesium composite cored wires are laid parallel to the first aluminum alloy layer, with a wire spacing of 2 mm (first wire layer). Finally, a layer of aluminum alloy with a thickness of 2.1 mm (second aluminum alloy layer) is uniformly clad onto the surfaces of the first aluminum alloy layer and the first wire layer. Then, steel-magnesium composite cored wire (second wire layer) is laid parallel to the surface of the second aluminum alloy layer; wherein the direction of the second wire layer is consistent with that of the first wire layer. Subsequently, an aluminum alloy layer with a thickness of 2.1 mm (third aluminum alloy layer) is uniformly clad onto the surfaces of the second aluminum alloy layer and the second wire layer. This process is repeated alternately to obtain the magnesium-aluminum composite preform, wherein the total number of aluminum alloy cladding layers is 10. During the cladding process, diffusion occurs between the molten aluminum alloy and the low-carbon steel to form Al₂O₃ and Al₂O₃. 13An Fe4 gradient transition layer is formed, thereby achieving a metallurgical bonding interface. An Al5Fe2 gradient layer is formed at the interface between low-carbon steel and particulate-reinforced magnesium matrix composites.

[0115] The rolling process involves rolling the magnesium-aluminum composite preform to obtain a rolled magnesium-aluminum composite preform. The rolling temperature is 450℃, the holding time is 30 minutes, and the total rolling deformation is 30%. During the rolling process, the steel-magnesium composite core wire in the magnesium-aluminum composite preform is densified, forming a steel-magnesium composite bundle structure, while the microstructure is refined.

[0116] Annealing treatment is performed on the rolled magnesium-aluminum composite preform to obtain the magnesium-aluminum composite material. The heat treatment temperature is 300℃, and the heat treatment time is 30 minutes.

[0117] Figure 5 This is a photograph of a magnesium-aluminum composite material prepared according to an embodiment of the present invention (made from steel-magnesium composite core wire with a diameter of 2 mm). From Figure 5 It can be seen that the multi-strand steel-clad magnesium alloy structure 1 is uniformly distributed in the three-dimensional continuous aluminum alloy binder phase 2, and exhibits good metallurgical bonding with the three-dimensional continuous aluminum alloy binder phase 2.

[0118] Figure 6 This is a SEM image of the aluminum / steel interface microstructure in the magnesium-aluminum composite material prepared in this embodiment; from Figure 6 This can be explained by the fact that a gradient structure interface layer is formed between low-carbon steel and metallic aluminum, with the layers from low-carbon steel to metallic aluminum being Al₅Fe₂ and Al₂Fe₃, respectively. 13 Fe4.

[0119] Figure 7 This is a SEM image of the steel-magnesium alloy interface in the magnesium-aluminum composite material prepared in this embodiment; from Figure 7 This can be explained by the fact that an A15Fe2 gradient structure interface layer is formed between the low-carbon steel and the AZ91 magnesium alloy.

[0120] Figure 8 This is a phase analysis diagram of the magnesium-aluminum composite material prepared in this embodiment; Figure 8 This demonstrates the in-situ formation of Al₅Fe₂ and Al₂ in magnesium-aluminum composites. 13 Fe4 phase, which is consistent with SEM results ( Figure 6 and Figure 7 It exhibits excellent consistency.

[0121] In the magnesium-aluminum composite material prepared in this embodiment, the volume fraction of steel is 5%, the volume fraction of particle-reinforced magnesium matrix composite material is 15%, and the volume fraction of aluminum is 80%.

[0122] Example 4

[0123] This embodiment prepares a magnesium-aluminum composite material, wherein the raw materials used are as follows: AZ91 magnesium alloy powder, SiC powder, low-carbon steel, and aluminum alloy welding wire. The AZ91 magnesium alloy powder has a particle size of 5-15 μm and a purity of 99.9%. The SiC particles have a particle size of approximately 15-55 μm. The low-carbon steel strip (H08A) has a width of 10 mm and a thickness of 0.2 mm. The aluminum alloy welding wire is ER5356 aluminum alloy welding wire.

[0124] The main steps include the following:

[0125] Mixing steps: Weigh the following components by mass percentage: 90% magnesium alloy powder and 10% reinforcing SiC particles. A planetary ball mill is used for mixing, with a ball-to-powder ratio of 20:1. The mill speed is set to 500 r / min, and the grinding ball diameter is 3-10 mm. To prevent excessive ball milling temperature and subsequent ball sticking, intermittent ball milling is used in this experiment. Each continuous ball milling session lasts 40 min, with a 15 min interval, for a total ball milling time of 8 h.

[0126] The steps for preparing steel-magnesium composite powder core wire are as follows: a low-carbon steel strip with a width of 10 mm and a thickness of 0.2 mm is rolled into a U-shaped steel strip, then the mixed powder is placed into the U-shaped steel strip, the U-shaped steel strip is sealed and rolled, and finally steel-magnesium composite powder core wire with an outer diameter of 2.5 mm is obtained through drawing and diameter reduction processes.

[0127] The steps for preparing the magnesium-aluminum composite preform are as follows: Magnesium-aluminum composite materials are prepared on an aluminum alloy substrate using arc additive manufacturing technology. Specifically, aluminum alloy welding wire is loaded into a wire feeder and melted into a molten state by a welding torch, then sprayed onto the aluminum alloy substrate. A wire feeding auxiliary device is installed on the robotic arm at the end of the welding torch and moves synchronously with the torch. The wire feeding speed of the wire feeder is 600 mm / min, the movement speed of the welding torch is 100 mm / min, the current is 90 A, and the pure argon shielding gas flow rate is 15 L / min. First, a layer of aluminum alloy with a thickness of approximately 2 mm (first aluminum alloy layer) is uniformly clad onto the aluminum alloy substrate. Then, steel-magnesium composite cored wires are laid parallel to the first aluminum alloy layer, with a wire spacing of 2 mm (first wire layer). Finally, a layer of aluminum alloy with a thickness of 2.1 mm (second aluminum alloy layer) is uniformly clad onto the surfaces of the first aluminum alloy layer and the first wire layer. Then, steel-magnesium composite powder core wire (second wire layer) is laid parallel to the surface of the second aluminum alloy layer; wherein the direction of the second wire layer is consistent with that of the first wire layer. Subsequently, an aluminum alloy layer with a thickness of 2.1 mm (third aluminum alloy layer) is uniformly clad on the surfaces of the second aluminum alloy layer and the second wire layer. This process is repeated alternately to obtain the magnesium-aluminum composite preform, wherein the total number of aluminum alloy cladding layers is 8. During the cladding process, diffusion occurs between the molten aluminum alloy and the low-carbon steel to form Al₂O₃ and Al₂O₃. 13 An Fe4 gradient transition layer is formed, thereby achieving a metallurgical bonding interface. An Al5Fe2 gradient layer is formed at the interface between low-carbon steel and particulate-reinforced magnesium matrix composites.

[0128] The rolling process involves rolling the magnesium-aluminum composite preform to obtain a rolled magnesium-aluminum composite preform. The rolling temperature is 480℃, the holding time is 30 minutes, and the total rolling deformation is 30%. During the rolling process, the steel-magnesium composite core wire in the magnesium-aluminum composite preform is densified, forming a steel-magnesium composite bundle structure, while the microstructure is refined.

[0129] Annealing treatment is performed on the rolled magnesium-aluminum composite preform to obtain the magnesium-aluminum composite material. The heat treatment temperature is 350℃, and the heat treatment time is 40 minutes.

[0130] In the magnesium-aluminum composite material prepared in this embodiment, the volume fraction of steel is 5%, the volume fraction of particle-reinforced magnesium matrix composite material is 20%, and the volume fraction of aluminum is 75%.

[0131] Example 5

[0132] This embodiment prepares a magnesium-aluminum composite material, wherein the raw materials used are as follows: AZ91 magnesium alloy powder, metallic Ti powder, low-carbon steel, and aluminum alloy welding wire. The AZ91 magnesium alloy powder has a particle size of 5-15 μm and a purity of 99.9%. The metallic Ti powder has a particle size of approximately 100 nm-55 μm. The low-carbon steel strip (H08A) has a width of 12 mm and a thickness of 0.2 mm. The aluminum alloy welding wire is ER5356 aluminum alloy welding wire.

[0133] The main steps include the following:

[0134] Mixing steps: Weigh the following components by mass percentage: 95% magnesium alloy powder and 5% reinforcing TiC particles. A planetary ball mill was used for mixing, with a ball-to-powder ratio of 20:1. The mill speed was set to 300 r / min, and the grinding ball diameter was 3-10 mm. To prevent excessively high milling temperatures and ball sticking, intermittent ball milling was used in this experiment. Each continuous ball milling session lasted 30 min, with a 12 min interval, for a total ball milling time of 9 h.

[0135] The steps for preparing steel-magnesium composite powder core wire are as follows: a low-carbon steel strip with a width of 12 mm and a thickness of 0.2 mm is rolled into a U-shaped steel strip, then the mixed powder is placed into the U-shaped steel strip, the U-shaped steel strip is sealed and rolled, and finally steel-magnesium composite powder core wire with an outer diameter of 3 mm is obtained through drawing and diameter reduction processes.

[0136] The steps for preparing the magnesium-aluminum composite preform are as follows: Magnesium-aluminum composite materials are prepared on an aluminum alloy substrate using arc additive manufacturing technology. Specifically, aluminum alloy welding wire is loaded into a wire feeder and melted into a molten state by a welding torch, then sprayed onto the aluminum alloy substrate. A wire feeding auxiliary device is installed on the robotic arm at the end of the welding torch and moves synchronously with the torch. The wire feeding speed of the wire feeder is 500 mm / min, the movement speed of the welding torch is 100 mm / min, the current is 90 A, and the pure argon shielding gas flow rate is 15 L / min. First, a layer of aluminum alloy with a thickness of approximately 2 mm (first aluminum alloy layer) is uniformly clad onto the aluminum alloy substrate. Then, steel-magnesium composite cored wires are laid parallel to the first aluminum alloy layer, with a wire spacing of 2 mm (first wire layer). Finally, a layer of aluminum alloy with a thickness of 3 mm (second aluminum alloy layer) is uniformly clad onto the surfaces of the first aluminum alloy layer and the first wire layer. Then, steel-magnesium composite powder core wire (second wire layer) is laid parallel to the surface of the second aluminum alloy layer; wherein the direction of the second wire layer is consistent with that of the first wire layer. Subsequently, a 3mm thick aluminum alloy layer (third aluminum alloy layer) is uniformly clad onto the surfaces of the second aluminum alloy layer and the second wire layer, wherein the total number of aluminum alloy cladding layers is 3. During the cladding process, diffusion occurs between the molten aluminum alloy and the low-carbon steel to form Al5Fe2 and Al2O3. 13An Fe4 gradient transition layer is formed, thereby achieving a metallurgical bonding interface. An Al5Fe2 gradient layer is formed at the interface between low-carbon steel and particulate-reinforced magnesium matrix composites.

[0137] The rolling process involves rolling the magnesium-aluminum composite preform to obtain a rolled magnesium-aluminum composite preform. The rolling temperature is 500℃, the holding time is 50 minutes, and the total rolling deformation is 45%. During the rolling process, the steel-magnesium composite core wire in the magnesium-aluminum composite preform is densified, forming a steel-magnesium composite bundle structure, while the microstructure is refined.

[0138] Annealing treatment is performed on the rolled magnesium-aluminum composite preform to obtain the magnesium-aluminum composite material. The heat treatment temperature is 350℃, and the heat treatment time is 50 minutes.

[0139] Figure 4 This is a photograph of a magnesium-aluminum composite material prepared according to an embodiment of the present invention (made from steel-magnesium composite powder core wire with a diameter of 3 mm); from Figure 4 It can be seen that the multiple steel-clad magnesium alloy structures 1 are uniformly distributed in the three-dimensional continuous aluminum alloy binder phase 2, and exhibit good metallurgical bonding with the three-dimensional continuous aluminum alloy binder phase 2. Furthermore, it should be noted that compared with other embodiments, due to the larger outer diameter D of the steel-magnesium composite core wire, the lateral spacing between the multiple steel-clad magnesium alloy structures 1 in this embodiment is reduced (the steel-clad magnesium alloy structure is flat), thereby reducing the inhibitory effect of the aluminum binder on crack initiation, and consequently leading to a decrease in the strength and toughness of the magnesium-aluminum composite material (therefore, the strength and toughness of the magnesium-aluminum composite material prepared in this embodiment are not as good as those in other embodiments).

[0140] In the magnesium-aluminum composite material prepared in this embodiment, the volume fraction of steel is 4%, the volume fraction of particle-reinforced magnesium matrix composite material is 20%, and the volume fraction of aluminum is 76%.

[0141] Comparative Example 1

[0142] Comparative Example 1 prepared a magnesium-aluminum composite material, which differed from Example 3 in that:

[0143] In the process of preparing steel-magnesium composite core wire, the width of the low-carbon steel strip is 15 mm and the thickness is 0.2 mm. Finally, the steel-magnesium composite core wire with an outer diameter D of 3.5 mm is obtained by drawing and reducing the diameter.

[0144] The other steps and parameters are the same as in Example 3.

[0145] Comparative Example 2

[0146] Comparative Example 2 prepared a magnesium-aluminum composite material, which differed from Example 3 in that:

[0147] In the rolling process, the rolling parameters are as follows: rolling temperature is 350℃, holding time is 50min, and total rolling deformation is 30%.

[0148] The other steps and parameters are the same as in Example 3.

[0149] Table 1 Mechanical properties of magnesium-aluminum composite materials prepared from pure magnesium alloys, Examples 1-5, and Comparative Examples 1-2.

[0150] Table 1

[0151]

[0152] As can be seen from the above embodiments, comparative examples, and Table 1:

[0153] (1) The magnesium-aluminum composite material prepared in the embodiments of the present invention has excellent strength and toughness.

[0154] (2) The material prepared in Comparative Example 1 has inferior performance compared to that in Example 3. The main reasons are as follows:

[0155] The effect of wire size on density: In Comparative Example 1, the outer diameter of the steel-magnesium composite core wire is 3.5 mm, which is larger than the 2 mm in Example 3, and the width of the low-carbon steel strip is 15 mm, which is larger than the 8 mm in Example 3. In the arc additive manufacturing process, larger wire sizes are not conducive to uniform heating and densification of the internal powder. On the one hand, the contact area between the powder and the external heat source is relatively small, resulting in uneven heat transfer and insufficient melting and diffusion of powder in some areas. On the other hand, larger wires, during the encapsulation, rolling, and subsequent drawing and diameter reduction processes, exhibit uneven internal stress distribution, which easily leads to defects and affects the material's density. In contrast, the smaller wire size in Example 3 better achieves uniform heating and densification, forming a denser steel-magnesium composite bundle structure, thereby improving the material's strength and toughness.

[0156] Interface bonding and microstructure uniformity: Due to the larger wire size in Comparative Example 1, the contact area between the molten aluminum alloy and the steel-magnesium composite core wire was relatively small during the cladding process, and the uniformity of the contact was also poor. This resulted in the formation of A15Fe2 and A1... 13 The Fe4 gradient transition layer is uneven and discontinuous, leading to a decrease in the quality of the metallurgical interface. Furthermore, the uniformity of the distribution of larger-sized wires in the composite material is not as good as in Example 3, resulting in poorer microstructure uniformity. In contrast, the smaller wires in Example 3 are able to be uniformly distributed in the aluminum alloy layer, making full contact with the molten aluminum alloy to form a uniform and continuous transition layer. This ensures the quality of the metallurgical interface and results in a more uniform and finer microstructure, thereby improving the overall performance of the material.

[0157] Differences in mechanical properties: Due to the lower density, poorer interfacial bonding, and uneven microstructure of the material in Comparative Example 1, stress concentration is easily generated at defects, weak interfacial areas, and regions with uneven microstructure when subjected to external forces, leading to premature crack propagation and fracture. In contrast, the material in Example 3 has higher density, better interfacial bonding, and a uniform and fine microstructure, enabling it to better withstand external forces and exhibiting higher tensile strength, elongation, and impact energy.

[0158] (3) The material prepared in Comparative Example 2 has inferior performance compared to that in Example 3. The main reasons are as follows:

[0159] Effect of rolling temperature: In Example 3, the rolling temperature was 450℃. At this temperature, atoms have higher activity, allowing for better densification of the steel-magnesium composite core wire in the magnesium-aluminum composite preform. Simultaneously, the higher temperature facilitates the diffusion of metal atoms, resulting in a more refined microstructure and increased grain boundaries. Grain boundaries can hinder dislocation movement, thereby improving the material's strength. Furthermore, refined grains allow the material to bear loads more evenly under stress, improving its toughness and elongation.

[0160] In Comparative Example 2, the rolling temperature was 350°C, which is relatively low, resulting in insufficient atomic activity. This leads to a lower degree of densification in the steel-magnesium composite core wire compared to Example 3, potentially resulting in more porosity or defects within the material. Simultaneously, the lower temperature hinders the diffusion of metal atoms, resulting in insufficient microstructure refinement and larger grain sizes. Under stress, dislocations in large-grained materials are more prone to movement within the grains, easily leading to stress concentration and premature fracture, thus reducing the material's strength, toughness, and elongation.

[0161] Effect of holding time: In Example 3, the holding time was 30 minutes. During this time, the internal structure of the material had sufficient time to homogenize and optimize. A suitable holding time allows for the formation of a good metallurgical interface between the magnesium alloy and the carbon steel cladding layer in the steel-magnesium composite core wire during the rolling process, improving the overall performance of the material.

[0162] In Comparative Example 2, the holding time was 50 minutes. Although the holding time was extended, the atomic diffusion rate was limited due to the low rolling temperature. The long holding time could not compensate for the effect of insufficient temperature, and it was difficult to form a good metallurgical bonding interface between the magnesium alloy and the low carbon steel cladding layer.

[0163] In summary, due to the low rolling temperature and unreasonable holding time during the rolling process in Comparative Example 2, the microstructure of the material was not ideal, with many defects, insufficient grain refinement, and incomplete metallurgical bonding interface formation, resulting in lower performance than the material prepared in Example 3.

[0164] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A magnesium-aluminum composite material, characterized in that, The magnesium-aluminum composite material comprises a three-dimensional continuous aluminum alloy binder phase and a steel-clad magnesium alloy bundle structure; wherein... The steel-clad magnesium alloy bundle structure includes multiple steel-clad magnesium alloy structures; wherein, the multiple steel-clad magnesium alloy structures are distributed in the continuous aluminum alloy binder phase; Each of the steel-clad magnesium alloy structures comprises a steel cladding layer and a particle-reinforced magnesium matrix composite material located within the steel cladding layer.

2. The magnesium-aluminum composite material according to claim 1, characterized in that, The steel cladding layer is a low-carbon steel cladding layer; preferably, the steel cladding layer is an H08A low-carbon steel cladding layer; and / or The particle-reinforced magnesium matrix composite material comprises a magnesium alloy binder phase and a particle-reinforcing phase distributed within the magnesium alloy binder phase; preferably, the particle-reinforcing phase is one or more of metallic Ti particles, SiC particles, and TiC particles; and / or In the magnesium-aluminum composite material, the volume fraction of steel is 4-15%, the volume fraction of particle-reinforced magnesium matrix composite material is 15-55%, and the volume fraction of aluminum is 30-81%.

3. The magnesium-aluminum composite material according to claim 1 or 2, characterized in that, In the magnesium-aluminum composite material: Al₅Fe₂ and Al₂Fe₂ are formed at the interface between the steel cladding and the continuous aluminum alloy binder phase. 13 Fe4 gradient transition layer; and / or When the particle-reinforced magnesium matrix composite contains aluminum, an Al5Fe2 gradient layer is formed at the interface between the steel cladding layer and the particle-reinforced magnesium matrix composite.

4. The magnesium-aluminum composite material according to any one of claims 1-3, characterized in that, The magnesium-aluminum composite material has a tensile strength of 343-427 MPa, an elongation of 7.5-15.2%, and an impact energy of 13-28 J.

5. The method for preparing the magnesium-aluminum composite material according to any one of claims 1-4, characterized in that, The preparation method of the magnesium-aluminum composite material includes the following steps: Mixing step: The magnesium alloy powder and reinforcing particles are ball-milled and mixed to obtain particle-reinforced magnesium alloy powder; Steps for preparing steel-magnesium composite powder core wire: The particle-reinforced magnesium alloy powder is placed in a steel structure with a accommodating cavity and processed into wire to obtain a steel-magnesium composite powder core wire with steel as the cladding layer and particle-reinforced magnesium alloy powder as the core layer. The steps for preparing the magnesium-aluminum composite preform are as follows: aluminum alloy is clad onto an aluminum alloy substrate to obtain a first aluminum alloy layer; the steel-magnesium composite core wire is laid on the first aluminum alloy layer to obtain a first wire layer; aluminum alloy is clad onto the first aluminum alloy layer and the first wire layer to obtain a second aluminum alloy layer; the steps of laying the steel-magnesium composite core wire and cladding the aluminum alloy are repeated 0 times or at least once to obtain the magnesium-aluminum composite preform. The rolling process involves rolling the magnesium-aluminum composite preform to obtain the rolled magnesium-aluminum composite preform. Annealing treatment: The rolled magnesium-aluminum composite preform is annealed to obtain the magnesium-aluminum composite material.

6. The method for preparing the magnesium-aluminum composite material according to claim 5, characterized in that, In the mixing step: By weight percentage, the particle-reinforced magnesium alloy powder comprises 85-98% magnesium alloy powder and 2-15% reinforcing particles; preferably, the magnesium alloy powder has a particle size of 5-15 μm; preferably, the reinforcing particles have a particle size of 100 nm-55 μm; and / or The process parameters for ball milling are as follows: ball-to-material ratio of 15:1-20:1, ball mill speed of 200-500 r / min, and grinding ball diameter of 3-10 mm; and / or During the ball milling and mixing process, an intermittent ball milling and mixing method is adopted. The duration of each continuous ball milling and mixing process is 20-40 minutes, and the interval is 10-15 minutes. The total time of the ball milling and mixing process is 8-10 hours.

7. The method for preparing the magnesium-aluminum composite material according to claim 5, characterized in that, In the step of preparing the steel-magnesium composite core wire: The steel structure with a cavity is a steel strip structure with a cavity; preferably, the steel strip is rolled into a steel strip structure with a cavity; more preferably, the width of the steel strip is 4-12 mm and the thickness is 0.05-0.2 mm; preferably, the cross-section of the steel strip structure with a cavity is U-shaped; and / or The steel structure with the accommodating cavity is made of low-carbon steel, preferably H08A low-carbon steel; and / or The outer diameter D of the steel-magnesium composite core wire is 1-3 mm.

8. The method for preparing the magnesium-aluminum composite material according to claim 5, characterized in that, In the step of preparing the magnesium-aluminum composite preform: Aluminum alloy layers were prepared using arc additive manufacturing technology; Preferably, the step of preparing the aluminum alloy layer using arc additive manufacturing technology includes: loading aluminum alloy welding wire into a wire feeder, melting it into a molten state through a welding torch and spraying it onto a substrate to form an aluminum alloy layer; wherein the substrate is one or more of aluminum alloy substrate, steel-magnesium composite core wire, and aluminum alloy layer; preferably, the wire feeding speed of the wire feeder is 500-650 mm / min, the movement speed of the welding torch is 90-110 mm / min, the current is 50-100 A, and the shielding gas flow rate is 10-20 L / min; more preferably, argon is used as the shielding gas.

9. The method for preparing the magnesium-aluminum composite material according to claim 5, characterized in that, In the step of preparing the magnesium-aluminum composite preform: The thickness of the first aluminum alloy layer is 2-4 mm; and / or The thickness of the second aluminum alloy layer is 0.5D-1.5D; where D is the outer diameter of the steel-magnesium composite core wire, in mm; and / or When laying the steel-magnesium composite core wire, the steel-magnesium composite core wire should be laid in parallel, and the spacing between the wires should be 1-3mm.

10. The method for preparing the magnesium-aluminum composite material according to claim 5, characterized in that, In the rolling process: the rolling temperature is 430-500℃, the holding time is 15-50 min, and the total rolling deformation is 25-45%; and / or In the annealing process: the annealing temperature is 200-350℃, and the annealing time is 20-60 minutes.

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