Layered dissimilar metal hot-pressing composite forming method

Abstract

The invention discloses a layered dissimilar metal hot-pressing composite forming method, and belongs to the field of layered metal material manufacturing. According to the method, firstly, at least two metal components are provided, the first metal component with the highest melting point is a metal block, the other components are metal powder, and the melting points are reduced layer by layer from a matrix block to a subsequent powder layer. Then the metal block and the powder are loaded into a mold in a layered structure, vacuumizing is conducted or protective atmosphere is introduced, and then two-stage hot-pressing compounding is conducted; in the first stage, rapid densification and interface pre-combination of the powder are achieved through medium temperature and high pressure; and in the second stage, interface metallurgy diffusion is promoted and interface thermal stress is actively relaxed by adopting high temperature and low pressure. The powder-solid composite unit is used as a base body to be repeatedly stacked, and the multi-layer composite material with the preset number of layers can be prepared layer by layer. The method effectively solves the problems of poor interface bonding, many brittle-hard phases, high residual stress, poor plate shape and the like in a traditional method, and has the advantages of safety, high efficiency, high yield, flexible thickness design, excellent comprehensive performance and the like.

Description

Technical Field

[0001] This invention relates to the field of layered metal material manufacturing, specifically a method for hot pressing composite forming of layered heterogeneous metals. Background Technology

[0002] Layered heterogeneous metal composites (such as copper / steel, aluminum / steel, titanium / aluminum, aluminum / magnesium, etc.) have shown great application potential in key fields such as aerospace, defense, and high-end equipment due to their unique functional-structural integration advantages. However, due to the inherent differences in physical properties and processing technology among the component metals, existing preparation methods generally face the common technical challenge of precise interface control, which severely restricts the large-scale production and industrial application of such materials.

[0003] Traditional explosive bonding methods suffer from significant pollution and safety risks, and the resulting products often exhibit defects such as poor shape, interface melting, or cracking. Furthermore, continuous and stable production is difficult to achieve. Traditional diffusion bonding methods generally have poor bonding performance, long production cycles, and high costs, making large-scale industrial production challenging. Rolling bonding methods introduce significant residual stress at the interface, leading to warping, twisting, and poor interface bonding in the composite plate. Welding bonding methods are strictly limited by the metallurgical compatibility between the welding material and the matrix, and their large heat-affected zone easily generates porosity and residual stress. Casting bonding methods result in intense interdiffusion of elements at the bonding interface, easily generating various brittle and hard phases, leading to unstable bonding performance. Friction stir welding bonding methods are prone to inclusion defects, have a narrow process window, and produce materials with limited thickness. Traditional powder sintering bonding methods have cumbersome processes, long cycles, and produce workpieces with low density. Laser cladding, cold spraying, and their composite processes (such as laser-assisted cold spraying) essentially fall under the category of surface engineering technology. Although these methods offer high coating bonding strength, they suffer from high investment and maintenance costs, narrow process windows, and difficulty in efficiently and economically preparing thick composite panels. Therefore, there is an urgent need to develop a new technology for preparing layered heterogeneous metal composite materials that enables continuous and efficient production, offers cost advantages, and combines high interfacial bonding strength, fewer brittle hard phases, low residual stress, excellent plate shape, and flexible thickness adjustment. Summary of the Invention

[0004] The purpose of this invention is to overcome the core problems in the preparation of existing layered heterogeneous metal composite materials, such as poor interfacial performance due to imperfect interfacial bonding mechanisms, difficulty in controlling brittle and hard phases, and high residual stress and poor plate shape caused by thermo-mechanical process mismatch. Simultaneously, addressing manufacturing bottlenecks such as low production efficiency, high cost, and specification curing, this invention proposes a powder-solid hot-pressing composite forming method. This method achieves simultaneous optimization of the microscopic interface and macroscopic forming quality of heterogeneous materials through the controlled diffusion / reaction of the powder-solid interface and the synergistic design of a two-stage hot-pressing process (medium-temperature high-pressure + high-temperature low-pressure), thereby systematically solving the technical coupling problems in composite material preparation.

[0005] The technical solution of the present invention:

[0006] A method for hot-pressing composite forming of layered heterogeneous metals, comprising the following steps:

[0007] (1) Provide at least two metal components, wherein the first metal component with the highest melting point is a metal block and the other metal components are metal powders; and the melting point of the metal components decreases layer by layer from the first metal component to the subsequent metal powder components.

[0008] (2) The metal block described in step (1) and at least one metal powder are loaded into the mold in a layered structure in contact with each other, and the metal block is tightly fitted with the mold cavity;

[0009] (3) Vacuum treatment or introduction of protective atmosphere into the mold cavity described in step (2) to obtain the preform assembly;

[0010] (4) Perform a two-stage hot-pressing composite process on the precast assembly obtained in step (3):

[0011] a) First stage (medium temperature and high pressure): The precast assembly is heated to a first temperature T1 and held at a first axial pressure P1; wherein, T1 satisfies 0.6T m ≤ T1 ≤ 0.75T m T m P1 is the melting point of the metal powder component with the highest melting point among the current components to be composited, and P1 ≥ 50 MPa;

[0012] b) Second stage (high temperature and low pressure): The precast assembly is heated to a second temperature T2, and the pressure is adjusted to a second axial pressure P2 for heat preservation; wherein, T2 satisfies 0.75T m ≤ T2 ≤ 0.9T m P2 satisfies 10 MPa ≤ P2 ≤ 50 MPa and P2 ≤ 0.5P1;

[0013] The layered composite material is obtained through the two-stage hot pressing process described above;

[0014] (5) Using the composite material obtained in step (4) as the matrix block for subsequent processing, repeat steps (2) to (4), that is, sequentially perform the steps of loading the matrix block and the next layer of metal powder components into the mold, atmosphere treatment, and two-stage hot pressing composite, until a multilayer heterogeneous metal composite material with a preset number of layers is obtained.

[0015] Preferably, in step (2), the metal block is controlled to fit the mold cavity, and the metal powder is used to fill the assembly gap between the metal block and the mold cavity wall.

[0016] Preferably, in step (4), after the second stage of hot pressing and bonding, controlled cooling is performed, and the axial pressure is gradually unloaded during the cooling process.

[0017] Preferably, in step (5), during the hot-pressing composite process of the metal powder components, the set value of the second temperature T2 decreases in a gradient manner.

[0018] Preferably, after step (1) and before step (2), the method further includes cleaning the bonding surface of the metal block and / or drying the metal powder.

[0019] Preferably, in step (1), the particle size D90 of the metal powder is ≤ 100 μm.

[0020] The design concept of this invention:

[0021] This pioneering approach employs a novel two-stage decoupled and synergistic process for powder-solid layered composite materials: "medium-temperature high-pressure densification and pre-bonding" and "high-temperature low-pressure diffusion and relaxation." This achieves a fundamental fusion of solid-state bonding (hot pressing) and powder metallurgy (sintering) in terms of process time and space. Using a high-melting-point metal bulk as a substrate, low-melting-point powder components are progressively composited layer by layer: The first stage, hot pressing, utilizes "medium-temperature high-pressure" bonding, forming a thin pre-bonding layer through medium-temperature insulation to prevent excessive growth of interfacial products at subsequent high temperatures, while achieving rapid powder densification through high pressure. The second stage employs "high-temperature low-pressure," completing metallurgical bonding through high-temperature insulation while actively relaxing interfacial thermal mismatch stresses using low pressure. Based on this principle, a gradient temperature hot pressing composite process has been developed, capable of preparing thick, multi-layered, asymmetric layered composite materials, systematically overcoming common technical challenges such as weak interfacial bonding, high residual stress, and difficulty in composite heterogeneous materials.

[0022] The beneficial effects of this invention are:

[0023] (1) Low residual stress and few brittle and hard phases

[0024] By employing hot-pressing composite technology without macroscopic plastic deformation, the problem of plate distortion caused by uneven deformation is eliminated at its root, and the excessive formation of brittle and hard phases at the interface is suppressed from a thermodynamic perspective. Through a two-stage hot-pressing composite process, the interfacial thermal mismatch stress is actively relaxed, which can reduce the residual stress at the interface by more than 96% compared with the traditional rolling composite method; at the same time, the thin pre-bonded layer formed can effectively suppress the coarsening of brittle and hard phases, and its total formation is reduced by more than 83% compared with the casting method.

[0025] (2) High yield and high finished product rate

[0026] By integrating the "atmosphere-temperature-pressure" process unit, the composite, densification, and sintering processes are completed simultaneously, directly driving the near-net-shape forming of materials. This integrated design significantly simplifies the production process, substantially reduces material waste and subsequent processing requirements, and, combined with a two-stage hot-pressing composite process, increases both the yield and product quality rate to over 95%, resulting in a significant overall cost advantage.

[0027] (3) Safe, efficient, and flexible in thickness

[0028] By integrating solid-state bonding with powder metallurgy principles, the manufacturing of thick, asymmetric, multilayer composite plates with high melting point differences, which traditionally relies on high-risk explosive bonding methods, is transformed into a precisely controllable, continuous, and stable process. Furthermore, this method has no special limitations on raw material thickness, depending only on the physical boundaries of the equipment and molds. Therefore, it can simultaneously achieve ultra-thickness bonding and ultra-thin precision forming, significantly improving production efficiency and the versatility and reliability of the process. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the production process of the present invention. Detailed Implementation

[0030] The raw materials used in the embodiments of the present invention are as follows:

[0031] Metal blocks: 304 austenitic stainless steel round plate, 35 mm in diameter and 5 mm in thickness; TA2 pure titanium block, 35 mm in diameter and 5 mm in thickness.

[0032] Metal powders: N6 pure nickel powder, particle size D90 ≤ 75 μm; T2 pure copper powder, particle size D90 ≤ 50 μm; AA6061 aluminum alloy powder, particle size D90 ≤ 50 μm; AZ31 magnesium alloy powder, particle size D90 ≤ 50 μm.

[0033] In this embodiment of the invention, the surface treatment of the metal block is as follows: the composite surface of the stainless steel block is mechanically polished with 180# and 400# sandpaper in sequence until the surface is smooth and there is no visible oxide layer; then, acetone and anhydrous ethanol are used in sequence to remove surface oil stains, and finally, hot air is used for drying.

[0034] In this embodiment of the invention, metal powder drying is performed by placing all metal powders in a vacuum drying oven and drying them at 80-120°C for 2-4 hours to remove adsorbed moisture.

[0035] The method for hot-pressing composite forming of layered heterogeneous metals according to the present invention will be described in detail below with reference to embodiments and accompanying drawings. A typical preparation process of this method is as follows: Figure 1 As shown, the main process includes three core steps: filling and spreading powder, atmosphere protection, and two-stage hot pressing and compounding.

[0036] Example 1

[0037] This example demonstrates the preparation of a copper / steel composite material using T2 pure copper powder and 304 stainless steel blocks as raw materials. The specific steps are as follows:

[0038] 1) Filling and spreading powder: Place the pretreated stainless steel block (35 mm in diameter, 5 mm in thickness) into the mold with its smooth surface facing upwards. Then, spread pure copper powder (particle size D90 ≤ 50 μm) evenly on the surface of the steel block to form a powder layer with a thickness of approximately 5 mm;

[0039] 2) Atmosphere protection: Argon gas is introduced into the mold cavity for protection;

[0040] 3) Hot-pressing composite:

[0041] a. First stage: The copper / steel layered preform in the mold is heated to 800℃ at a heating rate of 120℃ / min, and a constant pressure of 70 MPa is applied along the axial direction for 40 min.

[0042] b. Second stage: The preform is heated to 950 ℃ at a heating rate of 60 ℃ / min, and the axial pressure is adjusted to 35 MPa and held at the temperature and pressure for 40 min; then it is cooled to room temperature in the furnace, and the axial pressure is gradually unloaded during this cooling process.

[0043] Results: After demolding, a copper / steel composite material was obtained. Testing showed that the composite interface achieved good metallurgical bonding, with a shear strength of approximately 113 MPa.

[0044] Example 2

[0045] This example demonstrates the preparation of a copper / nickel / steel three-layer composite material using T2 pure copper powder, N6 pure nickel powder, and 304 stainless steel blocks as raw materials. The specific steps are as follows:

[0046] (I) First cycle: Preparation of nickel / steel composite material

[0047] 1) Filling and Powder Spreading: Place the pretreated 304 stainless steel block (35 mm in diameter, 5 mm in thickness) into the mold with its smooth surface facing upwards. Then, evenly spread N6 pure nickel powder (particle size D90 ≤ 75 μm) on the surface of the steel block to form a powder layer with a thickness of approximately 5 mm;

[0048] 2) Vacuum treatment: Evacuate the mold cavity to 10°C. ‒2 Pa;

[0049] 3) Hot-pressing composite:

[0050] a. First stage: Heat the nickel / steel layered preform in the mold to 900℃ at a heating rate of 120℃ / min, and apply a constant pressure of 75 MPa along the axial direction for 40 min.

[0051] b. Second stage: The preform is heated to 1100 ℃ at a heating rate of 60 ℃ / min, and the axial pressure is adjusted to 35 MPa. The temperature and pressure are maintained for 60 min. Then, it is cooled to room temperature in the furnace. During this cooling process, the axial pressure and vacuum conditions are gradually unloaded to obtain the nickel / steel composite material.

[0052] (ii) Second cycle: A copper layer is laminated onto the nickel surface of the nickel / steel composite material.

[0053] 1) Filling and spreading: Pure copper powder (particle size D90 ≤ 50 μm) is evenly spread on the nickel surface of the double-layer composite material after hot pressing, forming a powder layer with a thickness of about 5 mm;

[0054] 2) Vacuum treatment: Evacuate the mold cavity to 10°C. ‒2 Pa;

[0055] 3) Hot-pressing composite:

[0056] a. First stage: The copper / nickel / steel layered preform in the mold is heated to 800 ℃ at a heating rate of 120 ℃ / min, and a constant pressure of 70 MPa is applied along the axial direction for 40 min.

[0057] b. Second stage: The preform is heated to 950 ℃ at a heating rate of 60 ℃ / min, and the axial pressure is adjusted to 35 MPa and held at the temperature and pressure for 40 min; then it is cooled to room temperature in the furnace, and the axial pressure and vacuum conditions are gradually unloaded during the cooling process.

[0058] (III) Results

[0059] After demolding, a copper / nickel / steel three-layer composite material was obtained, with good bonding at all interfaces. The shear strength of the copper / nickel composite interface was approximately 187 MPa, and the shear strength of the nickel / steel composite interface was approximately 297 MPa.

[0060] Example 3

[0061] This example demonstrates the preparation of an aluminum / titanium / nickel three-layer composite material using AA6061 aluminum alloy powder, TA2 pure titanium block, and N6 pure nickel powder. The specific steps are as follows:

[0062] (I) First cycle: Preparation of titanium / nickel composite material

[0063] 1) Filling and spreading powder: N6 pure nickel powder (particle size D90 ≤ 75 μm) is evenly spread on the bottom layer of the mold to form a powder layer with a thickness of about 5 mm. Then, TA2 pure titanium blocks (diameter 35 mm, thickness 5 mm) with pretreated upper and lower surfaces are placed in the mold and placed on top of the nickel powder layer;

[0064] 2) Vacuum treatment: Evacuate the mold cavity to 10°C. ‒2 Pa;

[0065] 3) Hot-pressing composite:

[0066] a. First stage: Heat the titanium / nickel layered preform in the mold to 900℃ at a heating rate of 120℃ / min, and apply a constant pressure of 75 MPa along the axial direction for 40 min.

[0067] b. Second stage: The preform is heated to 1100 ℃ at a heating rate of 60 ℃ / min, and the axial pressure is adjusted to 35 MPa. The temperature and pressure are maintained for 60 min. Then, the preform is cooled to room temperature in the furnace, and the axial pressure and vacuum conditions are gradually unloaded to obtain the titanium / nickel composite material.

[0068] (ii) Second cycle: Aluminum layer is laminated onto the titanium surface of the titanium / nickel composite material.

[0069] 1) Filling and spreading powder: AA6061 aluminum alloy powder (particle size D90 ≤ 50 μm) is evenly spread on the surface of the double-layer composite titanium material after hot pressing and bonding to form a powder layer with a thickness of about 5 mm.

[0070] 2) Vacuum treatment: Evacuate the mold cavity to 10°C. ‒2 Pa;

[0071] 3) Hot-pressing composite:

[0072] a. First stage: The aluminum / titanium / nickel layered preform in the mold is heated to 450℃ at a heating rate of 60℃ / min, and a constant pressure of 50 MPa is applied along the axial direction for 30 min.

[0073] b. Second stage: The preform is heated to 580 ℃ at a heating rate of 30 ℃ / min, and the axial pressure is adjusted to 20 MPa and held at the temperature and pressure for 90 min. Then it is cooled to room temperature in the furnace, and the axial pressure and vacuum conditions are gradually unloaded during the cooling process.

[0074] (III) Results

[0075] After demolding, a three-layer aluminum / titanium / nickel composite material was obtained. Testing showed that all composite interfaces achieved good metallurgical bonding, with the aluminum / titanium composite interface exhibiting a shear strength of approximately 75 MPa and the titanium / nickel composite interface exhibiting a shear strength of approximately 150 MPa.

[0076] Example 4

[0077] This example uses AZ31 magnesium alloy powder, AA6061 aluminum alloy powder, TA2 pure titanium block, N6 pure nickel powder, and T2 pure copper powder as raw materials to prepare a five-layer composite material of magnesium / aluminum / titanium / nickel / copper. The specific steps are as follows:

[0078] (I) First cycle: Preparation of titanium / nickel composite material

[0079] 1) Filling and spreading powder: Place a TA2 pure titanium block (35 mm in diameter, 5 mm thick) into the mold with its smooth surface facing upwards. Then, spread N6 pure nickel powder (particle size D90 ≤ 75 μm) evenly on the surface of the titanium block to form a nickel powder layer with a thickness of approximately 5 mm;

[0080] 2) Vacuum treatment: Evacuate the mold cavity to 10°C. ‒2 Pa;

[0081] 3) Hot-pressing composite:

[0082] a. First stage: Heat the titanium / nickel layered preform in the mold to 900℃ at a heating rate of 120℃ / min, and apply a constant pressure of 75 MPa along the axial direction for 40 min.

[0083] b. Second stage: The preform is heated to 1100 ℃ at a heating rate of 60 ℃ / min, and the axial pressure is adjusted to 35 MPa. The temperature and pressure are maintained for 60 min. Then, the preform is cooled to room temperature in the furnace, and the axial pressure and vacuum conditions are gradually unloaded to obtain the titanium / nickel composite material.

[0084] (ii) Second cycle: A copper layer is laminated onto the nickel surface of the titanium / nickel composite material.

[0085] 1) Filling and spreading: T2 pure copper powder (particle size D90 ≤ 50 μm) is evenly spread on the nickel surface to form a copper powder layer with a thickness of about 5 mm;

[0086] 2) Vacuum treatment: Evacuate the mold cavity to 10°C. ‒2 Pa;

[0087] 3) Hot-pressing composite:

[0088] a. First stage: Heat the titanium / nickel / copper layered preform in the mold to 800 ℃ at a heating rate of 120 ℃ / min, and apply a constant pressure of 70 MPa along the axial direction for 40 min.

[0089] b. Second stage: The preform is heated to 950 ℃ at a heating rate of 60 ℃ / min, and the axial pressure is adjusted to 35 MPa. The temperature and pressure are maintained for 40 min. Then, it is cooled to room temperature in the furnace. During this cooling process, the axial pressure and vacuum conditions are gradually unloaded to obtain the titanium / nickel / copper composite material.

[0090] (III) Third cycle: Aluminum layer is composited on the titanium surface of the titanium / nickel / copper three-layer composite material.

[0091] The resulting titanium / nickel / copper three-layer composite material was demolded. The titanium surface was polished and cleaned to remove the oxide layer and contaminants, and then dried. The following steps were then performed:

[0092] 1) Filling and Powder Spreading: The treated composite material is placed into a mold as a new matrix, with the cleaned titanium surface facing upwards. Then, AA6061 aluminum alloy powder (particle size D90 ≤ 50 μm) is evenly spread on this surface to form a powder layer with a thickness of approximately 5 mm;

[0093] 2) Vacuum treatment: Evacuate the mold cavity to 10°C. ‒2 Pa;

[0094] 3) Hot-pressing composite:

[0095] a. First stage: The aluminum / titanium / nickel / copper layered preform in the mold is heated to 450 ℃ at a heating rate of 60 ℃ / min, and a constant pressure of 50 MPa is applied along the axial direction for 30 min.

[0096] b. Second stage: The preform is heated to 580 ℃ at a heating rate of 30 ℃ / min, and the axial pressure is adjusted to 20 MPa. The temperature and pressure are maintained for 90 min. Then, it is cooled to room temperature in the furnace, while the axial pressure and vacuum conditions are gradually unloaded to obtain an aluminum / titanium / nickel / copper four-layer composite material.

[0097] (iv) Fourth cycle: A magnesium layer is laminated onto the aluminum surface of the aluminum / titanium / nickel / copper four-layer composite material.

[0098] 1) Filling and spreading powder: AZ31 magnesium alloy powder (particle size D90 ≤ 50 μm) is evenly spread on the surface of the aluminum layer to form a powder layer with a thickness of about 5 mm;

[0099] 2) Vacuum treatment: Evacuate the mold cavity to 10°C. ‒2 Pa;

[0100] 3) Hot-pressing composite:

[0101] a. First stage: The magnesium / aluminum / titanium / nickel / copper layered preform in the mold is heated to 400 ℃ at a rate of 60 ℃ / min, and a constant pressure of 50 MPa is applied along the axial direction for 30 min.

[0102] b. Second stage: The preform is heated to 485 ℃ at a heating rate of 30 ℃ / min, and the axial pressure is adjusted to 20 MPa and held at the temperature and pressure for 60 min. Then it is cooled to room temperature in the furnace, and the axial pressure and vacuum conditions are gradually unloaded during the cooling process.

[0103] (v) Results

[0104] After demolding, a five-layer composite material of magnesium / aluminum / titanium / nickel / copper was obtained. Testing showed that all composite interfaces achieved good metallurgical bonding. Specifically, the shear strength of the magnesium / aluminum composite interface was approximately 37 MPa, the aluminum / titanium composite interface approximately 72 MPa, the titanium / nickel composite interface approximately 145 MPa, and the nickel / copper composite interface approximately 192 MPa.

[0105] It should be understood that the above description is merely an exemplary illustration of the principles and methods of the present invention, and not a limitation thereof. For those skilled in the art, based on the core technical concepts disclosed in this invention (such as layered filling and hot-pressing composite of powder and bulk materials), any equivalent substitutions, modifications, variations, or extensions without departing from the spirit and scope of this invention should be covered within the protection scope of this invention.

Claims

1. A method for hot-pressing composite forming of layered heterogeneous metals, characterized in that, In order, they include: (1) Provide at least two metal components, wherein the first metal component with the highest melting point is a metal block and the other metal components are metal powders; and the melting point of the metal components decreases layer by layer from the first metal component to the subsequent metal powder components. (2) The metal block described in step (1) and at least one metal powder are loaded into the mold in a layered structure in contact with each other, and the metal block is tightly fitted with the mold cavity; (3) Vacuum treatment or introduction of protective atmosphere into the mold cavity described in step (2) to obtain the preform assembly; (4) Perform a two-stage hot-pressing composite process on the precast assembly obtained in step (3): a) First stage: The precast assembly is heated to a first temperature T1 and held under a first axial pressure P1; wherein, T1 satisfies 0.6T m ≤ T1 ≤ 0.75T m T m P1 is the melting point of the metal powder component with the highest melting point among the current components to be composited, and P1 ≥ 50 MPa; b) Second stage: The precast assembly is heated to a second temperature T2, and the pressure is adjusted to a second axial pressure P2 for heat preservation; wherein, T2 satisfies 0.75T m ≤ T2 ≤ 0.9T m P2 satisfies 10 MPa ≤ P2 ≤ 50 MPa and P2 ≤ 0.5P1; The layered composite material is obtained through the two-stage hot-pressing composite process described above; (5) Using the composite material obtained in step (4) as the matrix block for subsequent processing, repeat steps (2) to (4), that is, sequentially perform the steps of loading the matrix block and the next layer of metal powder components into the mold, atmosphere treatment, and two-stage hot pressing composite, until a multilayer heterogeneous metal composite material with a preset number of layers is obtained.

2. The method for hot-pressing composite forming of layered heterogeneous metals according to claim 1, characterized in that, In step (2), the metal block is controlled to fit the mold cavity, and the metal powder is used to fill the assembly gap between the metal block and the mold cavity wall.

3. The method for hot-pressing composite forming of layered heterogeneous metals according to claim 1, characterized in that, In step (4), after the second stage of hot pressing, controlled cooling is performed, and the axial pressure is gradually unloaded during the cooling process.

4. The method for hot-pressing composite forming of layered heterogeneous metals according to claim 1, characterized in that, In step (5), during the hot-pressing composite process of the metal powder components, the set value of the second temperature T2 decreases in a gradient manner.

5. The method for hot-pressing composite forming of layered heterogeneous metals according to claim 1, characterized in that, After step (1) and before step (2), the process also includes cleaning the bonding surface of the metal block and / or drying the metal powder.

6. The method for hot-pressing composite forming of layered heterogeneous metals according to claim 1, characterized in that, The particle size D90 of the metal powder is ≤ 100 μm.

7. A layered heterogeneous metal composite material, characterized in that, It includes at least two metal layers bonded together by metallurgical means, with adjacent metal layers having different melting points.

8. The layered heterogeneous metal composite material according to claim 7, characterized in that, In the thickness direction, the melting points of each metal layer of the composite material are distributed in a gradient.

9. A layered heterogeneous metal composite material, characterized in that, Prepared by the method according to any one of claims 1 to 6.

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