Composite metal structure and preparation method thereof

Abstract

A composite metal structure and preparation method, wherein the preparation method of the metal composite structure comprises: in a main metal substrate processed into different structural shapes by a mechanical processing method, a composite transition layer of the same material as the main metal substrate is welded to the main metal substrate by 3D printing, and then the molten liquid of the auxiliary metal is added to the upper surface of the main metal transition layer composite structure of the solid main metal and the composite transition layer by a die-casting process, and finally the metal composite structure is obtained. The present invention can quickly and accurately manufacture a composite transition layer of any complex shape by 3D printing, and the die-casting process can efficiently fill the auxiliary metal into the composite transition layer to form a final metal composite structure. The main metal substrate can be mass-produced by conventional machines, and has good strength, corrosion resistance and decorative properties; the auxiliary metal is light and easy to process, and the composite transition layer can be tightly fused by the die-casting process.

Description

Technical Field

[0001] The present invention relates to the field of metal composite material science and engineering technology, and in particular to a metal composite structure combining traditional mechanical processing, 3D printing and die-casting processes and a preparation method of the metal composite structure. The metal composite structure can be widely used in the 3C field, such as handheld phones, tablet computers and watches. Background Art

[0002] Composite metal materials refer to materials with new properties that are formed by metallurgically combining two or more metals with different chemical and mechanical properties at the interface using composite technology. Composite metal materials are generally divided into main metals (such as titanium or stainless steel) and auxiliary metals (such as aluminum alloys and other low-cost metals).

[0003] For the appearance structural parts, the main metal has high strength and hardness, which can provide the desired external decorative appearance and stiffness level, but it is relatively heavy and expensive, difficult to process and may lead to waste of such materials, while the internal structural auxiliary metal is light, low cost and easy to process, but it cannot provide the desired decorative appearance and is not scratch-resistant. Therefore, composite metal can combine the advantages and disadvantages of main metal and auxiliary metal to achieve the advantages of light weight, low cost and easy processing, and can have the advantages of desired decorative appearance, hardness and scratch resistance. However, due to the differences in deformation degree and stress distribution of different metals, this non-uniformity makes it easy for composite metal to cause delamination and peeling in the weaker bonding areas when the material is subjected to external force, affecting the overall performance of the material.

[0004] At present, the composite metal manufacturing processes mainly include three categories: rolling composite, die-casting composite and hot isostatic pressing composite, each of which has its own advantages and disadvantages.

[0005] The first type, rolling bonding, is to heat two or more metal plates and then roll them through a rolling mill to combine them under high pressure. This method is relatively simple, but it is only suitable for single-plane bonding, and special-shaped structures are difficult to achieve, and cannot be produced continuously;

[0006] The second type, die-casting composite, is to put solid metal into the die-casting mold, and use the fluidity and wettability of liquid metal under high temperature and high pressure to make it contact with the surface of solid metal to form a mechanical bond through diffusion. After solidification, it is tightly connected with the solid metal to achieve the composite of the two metals. This process can be used to make complex composite metal products. However, due to the inconsistency of expansion coefficients of different metals, the cooling process will cause gaps and cracks in the bonding layer.

[0007] The third type, hot isostatic pressing, is a process that combines hot isostatic pressing with high temperature (usually 1000-2200℃) and high pressure (usually 100-200MPa). Under such extreme conditions, the two metals will undergo plastic deformation and diffusion under high temperature and high pressure, allowing the metals to fuse with each other. This process can eliminate the pores and defects in the middle of the two metal materials. However, its equipment structure is complex and costly, the process conditions are harsh and difficult to control, and the composite process requires a long time of heat preservation and pressure holding, which has low production efficiency.

[0008] Therefore, in view of the shortcomings of the prior art, it is necessary to provide a metal composite structure that combines traditional machining, 3D printing and die-casting processes and a method for preparing the metal composite structure to solve the shortcomings of the prior art. Summary of the invention

[0009] The first object of the present invention is to provide a method for preparing a metal composite structure by avoiding the shortcomings of the prior art. The method for preparing a metal composite structure can improve the bonding strength between the main metal and the auxiliary metal in the metal composite structure by using a composite transition layer. The metal composite structure obtained by the preparation method of the present invention can be widely used in the 3C field, such as handheld phones, tablet computers and watches.

[0010] The above-mentioned purpose of the present invention is achieved by the following technical measures:

[0011] A method for preparing a metal composite structure is provided, comprising the following steps:

[0012] S1. Take a main metal substrate processed into different structural shapes by a mechanical processing method, and then remove the oxide layer from the surface of the main metal substrate that needs 3D printing;

[0013] S2. A composite transition layer made of the same material as the main metal substrate is welded to the main metal substrate by 3D printing, and the composite transition layer is composed of multiple strength structures to obtain a main metal-composite transition layer composite structure of the main metal and the composite transition layer, and a side surface having the composite transition layer in the main metal-composite transition layer composite structure is defined as an upper surface, and the upper surface is cleaned and dried to remove the oxide layer;

[0014] S3, combining the auxiliary metal in a molten state with the upper surface of the main metal-composite transition layer composite structure in a mold through a die-casting process to obtain a composite metal blank, wherein the melting point of the auxiliary metal is lower than the melting point of the main metal substrate;

[0015] S4, performing heat treatment and strengthening on the composite metal blank obtained in S2, and finally obtaining the metal composite structure.

[0016] In the composite transition layer, the strength structures are distributed in a matrix.

[0017] Preferably, the thickness of the composite transition layer is 0.1 mm to 3 mm.

[0018] Preferably, the above-mentioned strength structure is a strength structure edited by 3D software according to required characteristics and strength.

[0019] The S1 is specifically performed by the following steps:

[0020] S1.1. Take the main metal substrate processed into different structural shapes by mechanical processing methods;

[0021] S1.2, removing the upper surface of the main metal substrate obtained in S1.1 to remove the oxide layer, and then cleaning and drying the main metal substrate as a whole.

[0022] Preferably, the above S2 is specifically performed by the following steps:

[0023] S2.1, heating the substrate powder of the composite transition layer and the main metal substrate to 100° C. to 110° C. when the oxygen content is below 4000 ppm;

[0024] S2.2, under the conditions of laser power of 100W~300W, scanning speed of 500mm / s~1200mm / s, spot diameter of 70μm~100μm, pulse frequency of 50Hz~200Hz, pulse width of 50ns~150ns, thickness of each printed layer not more than 0.05mm, printing speed of 500mm / s~1200mm / s, and printing temperature of 1200℃~1500℃, printing the composite transition layer; after printing, powder is removed, and cooled at room temperature with an oxygen content of less than 4000ppm to obtain a main metal-composite transition layer composite structure;

[0025] S2.3, the main metal-composite transition layer composite structure obtained in S2.2 is pickled to remove the oxide layer, then ultrasonically washed and cleaned, and finally air-dried.

[0026] Preferably, the above S3 is specifically as follows: placing the main metal-composite transition layer composite structure obtained in S2.2 into a die-casting mold, the die-casting temperature is 500℃~800℃, under the conditions of inert gas protection, die-casting pressure is 80MPa~120MPa, and die-casting time is 150s~220s, adding the auxiliary metal molten liquid in the melting furnace to the mold injection port, and injecting it through the mold to the upper surface of the solid main metal-composite transition layer composite structure to obtain a composite metal blank.

[0027] Preferably, the above S4 specifically comprises: performing T4 heat treatment and T6 heat treatment on the composite metal blank obtained in S2 to finally obtain the metal composite structure.

[0028] Preferably, the treatment temperature of the T4 heat treatment is 500° C. to 550° C., and the treatment time is 0.4 h to 0.6 h.

[0029] Preferably, the treatment temperature of the T6 heat treatment is 150° C. to 200° C., and the treatment time is 2.8 h to 3.3 h.

[0030] Preferably, the main metal substrate is made of titanium or stainless steel.

[0031] Preferably, the auxiliary metal is made of aluminum alloy or magnesium alloy.

[0032] The present invention provides a metal composite structure combining traditional mechanical processing, 3D printing and die-casting processes and a method for preparing the metal composite structure, wherein the method for preparing the metal composite structure comprises the following steps: S1. taking a main metal substrate processed into different structural shapes by a mechanical processing method, and then performing a deoxidation layer treatment on the surface of the main metal substrate that needs 3D printing; S2. welding a composite transition layer made of the same material as the main metal substrate to the main metal substrate by 3D printing, wherein the composite transition layer is composed of a plurality of strength structures, to obtain a main metal-composite transition layer composite structure in which the main metal and the composite transition layer are composited, defining an upper surface on a side surface having the composite transition layer in the main metal-composite transition layer composite structure, and performing a deoxidation layer cleaning and drying treatment on the upper surface; S3. combining a molten auxiliary metal with the upper surface of the main metal-composite transition layer composite structure in a mold by a die-casting process to obtain a composite metal blank, wherein the melting point of the auxiliary metal is lower than the melting point of the main metal substrate; S4. performing a heat treatment and strengthening on the composite metal blank obtained by S2, and finally obtaining the metal composite structure. The beneficial effects of the present invention are as follows: 1. Applicable to special-shaped structures: Since 3D printing can quickly and accurately manufacture a composite transition layer with any complex shape according to the design model, and the die-casting process can efficiently fill the auxiliary metal into the composite transition layer to form a final metal composite structure, it can be easily realized for 3C products with different specifications and structures, such as handheld phones, tablet computers and watches, etc., meeting the diverse design and manufacturing needs. 2. Excellent comprehensive performance: The main metal substrate can be mass-produced by traditional machinery, and has good strength, corrosion resistance and decorativeness; and the special-shaped structure of the composite transition layer of the present invention ensures its bonding strength with the main metal substrate and the auxiliary metal, the composite transition layer is easy to edit and requires less material, and the processing efficiency is high, thus realizing intelligent manufacturing; since the auxiliary metal is light and easy to process, it can be tightly fused with the composite transition layer through the die-casting process; by combining the main metal and the auxiliary metal through this technical solution, the advantages of the two metal materials can be fully utilized, and there will be no problem of bonding strength. 3. Simplified manufacturing process: Compared with the existing traditional metal composite material processing technology, the present invention processes the main metal substrate, composite transition layer and auxiliary metal through processes that can be easily realized by each of them. After the composite, it has perfect bonding strength, ensuring high reliability while avoiding the high difficulty of traditional processing technology. The simple and mature manufacturing process improves the product yield and reduces the manufacturing cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 Schematic diagram of the structure of the metal composite structure.

[0034] Figure 2 Schematic diagram of another metal composite structure.

[0035] Figure 3Schematic diagram of the cross section of the metal composite structure.

[0036] Figure 4 for Figure 3 A magnified view of the interface between the primary metal substrate and the secondary metal.

[0037] Figure 5 Schematic diagram of the strength structure.

[0038] exist Figures 1 to 5 Including:

[0039] Main metal substrate 1, composite transition layer 2, strength structure 21, auxiliary metal 3. DETAILED DESCRIPTION

[0040] The technical scheme of the present invention is further described in conjunction with the following examples. The experimental methods in the following examples are conventional methods unless otherwise specified.

[0041] Embodiment 1: A method for preparing a metal composite structure, comprising the following steps:

[0042] S1. Take the main metal substrate 1 processed into different structural shapes by mechanical processing methods, and then remove the oxide layer of the surface of the main metal substrate 1 that needs 3D printing, and enter S2;

[0043] S2. A composite transition layer 2 made of the same material as the main metal substrate 1 is welded to the main metal substrate 1 by 3D printing, and the composite transition layer 2 is composed of a plurality of strength structures 21, so as to obtain a main metal-composite transition layer composite structure in which the main metal and the composite transition layer 2 are composited; an upper surface is defined on one side of the main metal-composite transition layer composite structure having the composite transition layer 2, and the upper surface is subjected to a deoxidation layer cleaning and drying treatment; wherein the composite transition layer 2 is composed of a plurality of strength structures 21, and in the composite transition layer 2, the strength structures 21 are distributed in a matrix, and the thickness of the composite transition layer 2 is 0.1 mm to 3 mm; the strength structure 21 of the present invention is a strength structure 21 edited by 3D software according to the required characteristics and strength;

[0044] S3, combining the auxiliary metal 3 in a molten state with the upper surface of the composite structure of the main metal-composite transition layer in a mold through a die-casting process to obtain a composite metal blank, wherein the melting point of the auxiliary metal 3 is lower than the melting point of the main metal substrate 1;

[0045] S3, combining the auxiliary metal 3 in a molten state with the upper surface of the composite structure of the main metal-composite transition layer in a die by a die-casting process to obtain a composite metal blank, such as Figures 1 to 4 , and the melting point of the auxiliary metal 3 is lower than the melting point of the main metal substrate 1. Wherein, the material of the main metal substrate 1 is titanium or stainless steel, and the material of the auxiliary metal 3 is aluminum alloy or magnesium alloy;

[0046] S4, heat-treating and strengthening the composite metal blank obtained in S2 to finally obtain a metal composite structure.

[0047] In the present invention, the side surface where the main metal substrate 1 and the composite transition layer 2 are welded is defined as the upper surface, then the end where the strength structure 21 and the main metal substrate 1 are welded is the bottom end, and the end of the strength structure 21 away from the main metal substrate 1 is the top end. The maximum width of the top end of the strength structure 21 of the present invention is greater than the maximum width of the bottom end.

[0048] The strength structure 21 of the present invention is welded to the upper surface of the main metal substrate 1 by 3D printing, thus forming a good bonding strength. Then, under high temperature and high pressure, the molten liquid of the auxiliary metal 3 is injected at high temperature and high pressure to the upper surface of the solid main metal-composite transition layer composite structure, and the molten liquid flows into the gap between the strength structures 21 to form filling and fusion, thereby fusing the main metal substrate 1 and the auxiliary metal 3 to form a complete composite metal material with strong peeling force and strong shear force, and through heat treatment, the two metals reach a certain metal strength and hardness. The metal composite structure obtained by the present invention can be widely used in 3C and other fields, such as handheld phones, tablet computers and watches, etc. after subsequent mechanical processing and surface treatment.

[0049] The maximum width of the top of the strength structure 21 of the present invention is greater than the maximum width of the bottom, which further improves the peeling force. The strength structure 21 shown in the present invention is a structure with a larger top and a smaller bottom, and a plug-in structure is formed between the top and bottom of the strength structure 21, thereby forming a tight structure with the auxiliary metal 3. Therefore, the strength structure 21 that can form such a plug-in structure can be used as the strength structure 21 of the present invention. Figure 5 As shown, the present invention is Figure 5 The strength structure 21 of the present invention is described as an example. In addition, a plurality of convex points are distributed on the surface of the strength structure 21 of the present invention. The convex points further improve the bonding strength of the reinforced composite transition layer 2 after the molten liquid of the auxiliary metal 3 is filled.

[0050] S1 is specifically performed by the following steps:

[0051] S1.1, take a main metal substrate 1 processed into different structural shapes by mechanical processing method;

[0052] S1.2, removing the oxidation layer from the upper surface of the main metal substrate 1 obtained in S1.1, and then cleaning and drying the main metal substrate 1 as a whole.

[0053] It should be noted that the purpose of S1 of the present invention is to remove impurities such as oil, dust, oxide layer, etc. on the surface of the printed bonding surface before 3D printing, thereby improving the connection strength between the composite transition layer 2 and the main metal substrate 1.

[0054] In S2, the following steps are performed:

[0055] S2.1. When the oxygen content is below 4000 ppm, heat the substrate powder of the composite transition layer 2 and the main metal substrate 1 to 100° C. to 110° C.;

[0056] S2.2, under the conditions of laser power of 100W~300W, scanning speed of 500mm / s~1200mm / s, spot diameter of 70μm~100μm, pulse frequency of 50Hz~200Hz, pulse width of 50ns~150ns, thickness of each printed layer not more than 0.05mm, printing speed of 500mm / s~1200mm / s, and printing temperature of 1200℃~1500℃, print the composite transition layer 2; after printing, remove the powder, cool at room temperature with oxygen content below 4000ppm, and obtain the main metal-composite transition layer composite structure;

[0057] S2.3, the main metal-composite transition layer composite structure obtained in S2.2 is pickled to remove the oxide layer, then ultrasonically washed and cleaned, and finally air-dried.

[0058] S3 is specifically as follows: the main metal-composite transition layer composite structure obtained in S2.2 is placed into a die-casting mold at a die-casting temperature of 500°C to 800°C. Under the conditions of inert gas protection, a die-casting pressure of 80MPa to 120MPa, and a die-casting time of 150s to 220s, the molten auxiliary metal 3 in the melting furnace is added to the injection port of the mold, and injected through the mold to the upper surface of the solid main metal-composite transition layer composite structure to obtain a composite metal blank.

[0059] S4 is specifically: performing T4 heat treatment and T6 heat treatment on the composite metal blank obtained in S2, and finally obtaining a metal composite structure. The treatment temperature of T4 heat treatment is 500℃~550℃, and the treatment time is 0.4h~0.6h. The treatment temperature of T6 heat treatment is 150℃~200℃, and the treatment time is 2.8h~3.3h.

[0060] The metal composite structure obtained by the present invention has a peel strength of 5N / mm and a shear force of 400Mpa-550Mpa, while the hardness of the main metal is 280HV-340HV, the weight of the metal composite structure is reduced by about 50%, and the yield is 99.8%. At present, the peel strength of the metal composite structure obtained by rolling and die-casting without a composite transition layer 2 is 2N / mm, and the shear force is 170Mpa-250Mpa.

[0061] The metal composite structure obtained by the preparation method has a main metal substrate 1 located in the outer layer, directly in contact with the external environment, providing good wear resistance and hardness, high strength and decorative appearance; the auxiliary metal 3 is located in the inner layer, in contact with the strength structure 21 of the composite transition layer 2, and the auxiliary metal 3 exerts its good processing, thermal conductivity and light weight characteristics; the composite transition layer 2 is located in the middle, and through other strength structures 21 such as T-shaped barbs, the main metal substrate 1 and the auxiliary metal 3 are tightly integrated. During the working process, the main metal substrate 1 of the outer layer withstands external forces such as scratches and collisions to protect the internal structure. The auxiliary metal 3 of the inner layer can be connected with other structural parts to reduce the difficulty of processing and reduce the overall weight. The composite transition layer 2 is formed into a special structure of any shape through 3D editing, which increases the physical bonding force between the main metal substrate 1 and the auxiliary metal 3 and ensures overall stability and reliability.

[0062] The beneficial effects of the preparation method of the metal composite structure are as follows: 1. Applicable to special-shaped structures: Since 3D printing can quickly and accurately manufacture a composite transition layer 2 with any complex shape according to the design model, and the die-casting process can efficiently fill the auxiliary metal 3 into the composite transition layer 2 to form the final metal composite structure; for 3C products of different specifications and structures, such as handheld phones, tablet computers and watches, etc., it can be easily realized, meeting the diverse design and manufacturing needs. 2. Excellent comprehensive performance: The main metal substrate 1 can be mass-produced by traditional machines, with good strength, corrosion resistance and decorativeness; and the special-shaped structure of the composite transition layer 2 of the present invention ensures its bonding strength with the main metal substrate 1 and the auxiliary metal 3, the composite transition layer 2 is easy to edit and requires less material, and the processing efficiency is high, thus realizing intelligent manufacturing; since the auxiliary metal 3 is light and easy to process, the composite transition layer 2 can be tightly fused through the die-casting process; by combining the main metal and the auxiliary metal 3 through this technical solution, the advantages of the two metal materials can be fully utilized, and there will be no problem of bonding strength. 3. Simplified manufacturing process: Compared with the existing traditional metal composite material processing technology, the present invention processes the main metal substrate 1, the composite transition layer 2 and the auxiliary metal 3 through processes that can be easily implemented by each of them, and has perfect bonding strength after being composited, which ensures high reliability while avoiding the high difficulty of traditional processing technology. The simple and mature manufacturing process improves the product yield and reduces the manufacturing cost.

[0063] Example 2: A metal composite structure is prepared by the preparation method of the metal composite structure of Example 1.

[0064] The main metal substrate 1 of the metal composite structure is located in the outer layer, directly in contact with the external environment, providing good wear resistance and hardness, high strength and decorative appearance; the auxiliary metal 3 is located in the inner layer, in contact with the strength structure 21 of the composite transition layer 2, and the auxiliary metal 3 exerts its good processing, thermal conductivity and light weight characteristics; the composite transition layer 2 is located in the middle, and through other strength structures 21 such as T-shaped barbs, the main metal substrate 1 and the auxiliary metal 3 are tightly integrated. During the working process, the main metal substrate 1 of the outer layer withstands external scratches, collisions and other forces to protect the internal structure. The auxiliary metal 3 of the inner layer can be connected with other structural parts to reduce the difficulty of processing and reduce the overall weight. The composite transition layer 2 is formed into a special structure of any shape through 3D editing, which increases the physical bonding force between the main metal substrate 1 and the auxiliary metal 3 and ensures overall stability and reliability.

[0065] The main metal substrate 1 of the metal composite structure can be mass-produced by traditional machinery, and has good strength, corrosion resistance and decorative properties. The auxiliary metal 3 is light and easy to process. The metal composite structure of the present invention can give full play to the advantages of the two metal materials by combining the main metal and the auxiliary metal 3, and there will be no problem of bonding strength. It can also reduce the amount of the main metal substrate 1, achieve a weight reduction of about 50%, and a yield of 99.8%. The metal composite structure is suitable for 3C products of different specifications and structures, such as handheld phones, tablet computers and watches, etc., meeting the diverse design and manufacturing needs.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A method for preparing a metal composite structure, characterized in that: The following steps are involved: S1. Take a main metal substrate processed into different structural shapes by a mechanical processing method, and then remove the oxide layer on the surface of the main metal substrate that needs 3D printing, and enter S2; S2. Weld a composite transition layer of the same material as the main metal substrate to the main metal substrate by 3D printing, and the composite transition layer is composed of multiple strength structures to obtain a main metal-composite transition layer composite structure of a main metal and a composite transition layer, define a side surface having the composite transition layer in the main metal-composite transition layer composite structure as an upper surface, and remove the oxide layer, clean and dry the upper surface; S3, combining the auxiliary metal in a molten state with the upper surface of the main metal-composite transition layer composite structure in a mold through a die-casting process to obtain a composite metal blank, wherein the material of the main metal substrate is titanium or stainless steel; the material of the auxiliary metal is an aluminum alloy or a magnesium alloy; S4, heat-treating and strengthening the composite metal blank obtained in S2 to finally obtain the metal composite structure; The S2 is specifically performed by the following steps: S2.1, heating the substrate powder of the composite transition layer and the main metal substrate to 100°C~110°C when the oxygen content is below 4000ppm; S2.2, printing each layer with a thickness of 100~300mm at a laser power of 100W~300W, a scanning speed of 500mm / s~1200mm / s, a spot diameter of 70μm~100μm, a pulse frequency of 50Hz~200Hz, a pulse width of 50ns~150ns, and a thickness of 100~1500nm. The composite transition layer is printed under the conditions of a thickness of no more than 0.05 mm, a printing speed of 500 mm / s to 1200 mm / s, and a printing temperature of 1200°C to 1500°C; after printing, the powder is removed and cooled at room temperature with an oxygen content of less than 4000 ppm to obtain a main metal-composite transition layer composite structure; S2.3, the main metal-composite transition layer composite structure obtained in S2.2 is pickled to remove the oxide layer, then ultrasonically washed and cleaned, and finally air-dried; The S3 is specifically as follows: placing the main metal-composite transition layer composite structure obtained in S2.2 into a die-casting mold, with a die-casting temperature of 500°C to 800°C, adding the auxiliary metal molten liquid in the melting furnace to the injection port of the mold under the conditions of inert gas protection, a die-casting pressure of 80MPa to 120MPa, and a die-casting time of 150s to 220s, and injecting it through the mold to the upper surface of the solid main metal-composite transition layer composite structure to obtain a composite metal blank; In the composite transition layer, the strength structure is distributed in a matrix, and the thickness of the composite transition layer is 0.1 mm to 3 mm.

2. The method for preparing a metal composite structure according to claim 1, characterized in that: The S1 is specifically performed by the following steps: S1.

1. Take the main metal substrate processed into different structural shapes by mechanical processing methods; S1.2, removing the upper surface of the main metal substrate obtained in S1.1 to remove the oxide layer, and then cleaning and drying the main metal substrate as a whole.

3. The method for preparing a metal composite structure according to claim 2, characterized in that: The S4 specifically comprises: performing T4 heat treatment and T6 heat treatment on the composite metal blank obtained in S2, and finally obtaining the metal composite structure; The treatment temperature of the T4 heat treatment is 500°C to 550°C, and the treatment time is 0.4h to 0.6h; The treatment temperature of the T6 heat treatment is 150° C. to 200° C., and the treatment time is 2.8 h to 3.3 h.

4. A metal composite structure, characterized in that: The metal composite structure is prepared by the method for preparing the metal composite structure according to any one of claims 1 to 3.

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