A preparation method of a bimetallic composite plate using a Bridgman method

Abstract

The present application discloses a preparation method of a bimetallic composite plate by a Bridgman method, wherein the bimetallic composite plate is composed of a metal substrate and a cladding plate, wherein the cladding plate is obtained by sintering after granulating metal powder, and the steps include: (1) the metal substrate is corrected and leveled, and the top surface is sequentially rusted, degreased and roughened, and cleaned for use; (2) the metal powder is mixed and granulated, poured on the top surface of the metal substrate, and smoothed after vibration; (3) the metal substrate with the top surface covered with metal mixed particles is horizontally sent into a regional sintering furnace, inert gas protection is introduced, and heated to the liquefaction sintering temperature of the metal particles, the temperature zone width is 10-50cm, and the regional high temperature is gradually passed at a speed of 30-200cm / h to complete sintering; (4) cooling gas is blown to the metal substrate at the bottom of the regional sintering furnace outlet, and the bimetallic composite plate is obtained after the other side is naturally cooled. The method sets the regional temperature control and cooling crystallization mode for the preparation of the bimetallic plate, so that the bimetallic composite plate has high density, strength and material consistency.

Description

Technical Field

[0001] The present application relates to a method for preparing a bimetallic composite plate using a Bridgman process, and belongs to the technical field of metal composite plate preparation. Background Art

[0002] Bimetallic composite plate refers to a plate with another metal welded on a layer of metal, which saves resources and reduces costs while meeting special performance requirements. In a broad sense, bimetallic composite process methods can be divided into three categories according to the material state: solid / liquid, liquid / liquid, and solid / solid composite. A typical example of the solid / liquid method is to pour or cast a layer of metal on a substrate. This method relies on the heat of the molten metal itself to produce an interface bond, but due to the short action time, the interface bond is difficult to guarantee. The liquid / liquid composite method is also called the double liquid casting composite method. When using this process, the pouring speed of the two metals needs to be well controlled during the pouring process. The solid / solid composite method usually includes explosive composite, explosive rolling composite, rolling composite, etc. The explosive bonding method has a low degree of mechanization, poor working conditions, and a certain degree of danger. The prepared bimetallic material is deformed and uneven, and is rarely used in plate production. The direct rolling method can be divided into hot rolling method and cold rolling method. The composite plate manufactured by the direct rolling method has the following advantages: (1) the size of the composite plate surface can be expanded; (2) the production cost is low and the product is competitive in the market; (3) it is suitable for mass production; (4) it is easy to establish a production line with a high degree of automation; (5) the product has good bonding performance and stable quality. Rolling composite is an effective process for producing layered composite plates, which can produce relatively thin plate and strip composite materials. However, when rolling high-melting-point metals, high temperature and high pressure are required, and the requirements for rolling rollers are high. The thickness of the composite plate is difficult to control, and the production consistency and stability are poor. It is mostly suitable for the production of thick composite plates and slabs. In addition, there is semi-solid squeeze casting technology for the manufacture of composite parts, but the plate area is large and the tonnage of the press is required to be large. The continuous casting and rolling process is suitable for mass production, but it has high requirements for rolling mills and requires multiple rolling passes to achieve. It cannot be processed in small batches or special plate specifications, and can only be achieved in large steel plants.

[0003] Powder metallurgy is an industrial technology that produces metal powder or uses metal powder (or a mixture of metal powder and non-metallic powder) as raw material, and then forms and sinters it to produce metal materials, composite materials and various types of products. Powder metallurgy can minimize the segregation of alloy components, eliminate coarse and uneven casting structures, save metal and reduce costs. Powder metallurgy can ensure the correctness and uniformity of material components in proportion, and reduce costs through mass production. The sintering of powder metallurgy is carried out in a high-temperature furnace or vacuum furnace in a protective atmosphere. Sintering is different from metal melting. At least one element remains in a solid state during sintering. During the sintering process, the powder particles undergo a series of physical and chemical processes such as diffusion, recrystallization, welding, combination, and dissolution to become metallurgical products with a certain porosity. Powder metallurgy products have high porosity, poor strength and toughness, and high die costs. Powder metallurgy can achieve near-net shaping and automated mass production, which can effectively reduce the consumption of resources and energy in production. Generally, sintered parts can be used directly. In order to solve the defects of powder metallurgy products, some parts that require high dimensional accuracy and high hardness and wear resistance must be subjected to post-sintering treatment. Post-treatment includes precision pressing, rolling, extrusion, quenching, surface quenching, oil immersion, and infiltration.

[0004] Chinese patent CN109500400.A discloses a process for composite rolling of metal powder and metal strip. It includes a feeding roller, a steel plate surface treatment device, a front roller, a feeding device, a powder rolling mill, an intermediate roller, an online heating furnace, a hot rolling mill and a rear roller connected in sequence and arranged in an assembly line; the intermediate roller is divided into a front intermediate roller and a rear intermediate roller, and the online heating furnace is located between the front intermediate roller and the rear intermediate roller; the powder rolling mill and the hot rolling mill are both horizontal rolling mills with rollers arranged up and down, and the metal plate or metal strip runs continuously in the rolling direction. Continuous online batch production of high-quality metal plates (strips) is achieved. This process combines the advantages of powder metallurgy and rolling processes. Through rolling, preliminary forming is carried out to achieve powder metallurgy sintering and reduce the cost of die pressing. As mentioned above, the subsequent hot rolling reduces the porosity of powder metallurgy sintering. This process, like the rolling method mentioned above, requires the investment of multiple rolling mills, and the production equipment cost is high. It is difficult for general enterprises to produce, and this process is still essentially a powder metallurgy process.

[0005] The sintering method is basically the same as the powder metallurgy method, except that the powder is directly spread without pressure. In a protective atmosphere or vacuum environment, the powder particles are combined with the composite substrate by heating. Since the sintering temperature is lower than the melting point of the high-melting-point pure metal component during the sintering process, the microstructure and properties of the alloy coating are very uniform, which is a beneficial supplement to the rolling method (Material Development and Application, 2008, V23, No5, P48-51). The metal composite plate obtained by the sintering method has a large porosity, so this method can only be used to prepare composite metal materials with high porosity, and its scope of application is very narrow.

[0006] Overlay welding or welding method has the advantages of being direct and convenient, and has many applications in the wear-resistant plate industry. However, due to the narrow welding pool and insufficient insulation measures, the surface cracks are more serious, the surface is not smooth, and the welding efficiency is quite low.

[0007] Considering the advantages and disadvantages of the above-mentioned various process methods, seeking an economically feasible process method for preparing a bimetallic composite plate has become the focus of people's attention.

[0008] The Bridgman crystal growth method is a commonly used crystal growth method. It is divided into the vertical Bridgman method (VB) and the horizontal Bridgman method (HB). The horizontal Bridgman method is a method for preparing large-area shaped thin flake crystals successfully developed by BarIIacapob. The raw materials are placed in a boat-shaped crucible, and the crucible is passed horizontally through the heating zone, and the raw materials are melted and crystallized. There are high-temperature zones and low-temperature zones in the furnace in the horizontal direction. First, the crucible is placed in the high-temperature zone in the furnace to melt all the raw materials. When the top of the seed crystal begins to melt, the crucible begins to move to the low-temperature zone, the melt continues to crystallize, and the crystal grows slowly. This method is used for the growth of gallium arsenide and some compound semiconductor crystals. This method has the following characteristics: the open crucible makes it easy to observe the growth of crystals; since the height of the melt is much smaller than its surface size, it is beneficial to remove volatile impurities, and it is also beneficial to reduce the convection intensity and improve the stability of the crystallization process; the open melt surface makes it possible to add activating ions to the melt at any stage of crystallization; through multiple crystallization methods, the raw materials can be chemically purified. Summary of the invention

[0009] In order to solve the above problems, a method for preparing a bimetallic composite plate by a Bridgman method is provided. In this method, a substrate is used as a crucible, a molten composite metal layer is used as crystal growth, and a regional temperature control method and a cooling crystallization method suitable for the preparation of the bimetallic plate are set. The bi(multi)metallic plate can be prepared simply, quickly and economically. The bimetallic composite plate obtained by this method has high density, strength, and material consistency, and the interface bonding force between the bimetals of the bimetallic composite plate is relatively high.

[0010] According to one aspect of the present application, a method for preparing a bimetallic composite plate by a Bridgman process is provided, wherein the bimetallic composite plate is composed of a metal substrate and a cladding plate, wherein the cladding plate is obtained by granulating metal powder and then sintering the cladding plate, comprising the following steps:

[0011] (1) Correct the metal substrate to make it flat, remove rust, oil and roughen the top surface in turn, clean it and set it aside;

[0012] (2) Mix the metal powders and granulate them, pour them on the top surface of the metal substrate, and smooth them after compaction;

[0013] (3) The metal substrate with the metal mixed particles on the top surface is horizontally sent into the regional sintering furnace, and inert gas protection is introduced, and it is heated to the liquefaction sintering temperature of the metal particles. The width of the temperature zone is 10-50 cm, and it gradually passes through the regional high temperature at a speed of 30-200 cm / h to complete the sintering;

[0014] (4) Blowing cooling gas to the metal substrate at the bottom of the regional sintering furnace outlet, and the other side is naturally cooled to obtain the bimetallic composite plate.

[0015] Specifically, the amount of metal powder added is determined by calculation according to the required thickness of the cladding plate. The metal powder is completely and evenly spread. The thickness of the metal mixed particles added to the cladding plate is 0.3-3 times the thickness of the metal substrate.

[0016] Optionally, the sintering temperature of the regional sintering furnace in step (3) is 10-50° C. higher than the melting temperature of the metal powder for preparing the cladding plate, and needs to reach at least 90% of the melting amount of the powder.

[0017] Specifically, the melting temperature of the metal powder of the cladding plate needs to be measured by technicians in this field according to the selected metal powder components to determine the melting temperature of the metal powder. The measurement method can be carried out using instruments such as differential scanning calorimeter and differential thermal analyzer according to relevant national standards or other methods.

[0018] Optionally, the metal substrate is one of a copper plate, a steel plate, a stainless steel plate, a tungsten alloy plate and a molybdenum alloy plate.

[0019] Preferably, the metal substrate is a steel plate or a stainless steel plate.

[0020] Optionally, the metal powder of the cladding plate is one of aluminum silicon alloy powder, copper silicon alloy powder and chromium iron alloy powder.

[0021] Specifically, the cladding plate powder includes aluminum powder, aluminum alloy powder, aluminum or aluminum alloy and tungsten, molybdenum, silicon, silicon carbide, boron carbide, titanium carbide, iron carbide, titanium nitride, zirconium boride, iron boride, chromium boride powder; copper powder, copper alloy powder, copper or copper alloy and tungsten, molybdenum, silicon, silicon carbide, boron carbide, titanium carbide, iron carbide, titanium nitride, zirconium boride, iron boride, chromium boride powder; nickel-based, iron-based self-fluxing alloy powder, iron-based or nickel-based self-fluxing alloy and tungsten, molybdenum, silicon, silicon carbide, boron carbide, titanium carbide, iron carbide, titanium nitride, zirconium boride, iron boride, chromium boride powder; wear-resistant cast iron powder, high carbon iron-based powder, high carbon nickel-based powder, high boron iron-based powder, high boron nickel-based powder, high silicon iron-based powder, high silicon nickel-based powder; or powders combined with each other.

[0022] Optionally, the melting point of the metal powder of the cladding plate is lower than the melting point of the metal substrate by more than 100°C.

[0023] Optionally, the zone sintering furnace adopts medium or high frequency induction heating or heating by one of resistance wire, silicon carbon rod and silicon molybdenum rod.

[0024] Optionally, the inert gas in step (3) is nitrogen.

[0025] The beneficial effects of this application include but are not limited to:

[0026] 1. According to the Bridgman method for preparing a bimetallic composite plate of the present application, the bimetallic composite plate can be prepared simply, quickly and economically. The method can achieve a bimetallic composite plate having high density, strength, and material consistency, and the interface bonding force between the bimetals of the obtained bimetallic composite plate is relatively high, which solves the problems of uneven surface and many surface cracks caused by the current bimetallic composite plate using welding technology.

[0027] 2. According to the Bridgman method for preparing a bimetallic composite plate of the present application, the molten metal of the cladding plate crystallizes along the horizontal direction of the metal substrate and is gradually pushed out from the high temperature zone. The liquid phase begins to cool, and the molten metal begins to nucleate and crystallize, growing in the opposite direction of the movement of the plate. The width of the metal substrate is large, forming multiple crystals that grow side by side forward; the side-by-side crystals grow along the length direction of the plate, and the grain length is significantly longer than that of the hot-rolled plate. Due to the lack of lateral grain boundaries, the bimetallic composite plate prepared in the present application will have better toughness and tensile strength than the hot-rolled plate.

[0028] 3. According to the Bridgman method for preparing a bimetallic composite plate of the present application, by using a protective gas blown cold from the bottom of the furnace mouth, the gas at the bottom of the crystal growth front and the core is discharged in time, thereby solving the problem of high porosity in methods such as powder metallurgy, sintering, direct casting, and liquid phase method. The hot rolling method has a slightly lower porosity but cannot completely eliminate the internal pore problem. This method controls the regional sintering conditions and combines a specific cooling method to enable the bimetallic composite plate to obtain high density without multiple processes.

[0029] 4. According to the preparation method of the Bridgman method bimetallic composite plate of the present application, by limiting the width of the temperature zone, it is ensured that the molten liquid is easy to control, and the liquid phase for crystal growth can be provided above 10 cm; if it exceeds 50 cm, the equipment heating temperature zone is too long, resulting in excessive equipment investment; by limiting the moving rate, it is ensured that the crystal can grow along the length direction of the substrate surface, and too low a moving rate causes energy waste and low efficiency; it also avoids too high a moving rate so that the crystal has no time to grow, and defects are easily formed in the middle of the final surface layer and between the substrate. By limiting the width of the temperature zone and the moving rate, the powder is fully melted, and the coating crystal is fully grown, so that the impurities such as oxides in the powder and melt in the coating plate are driven to the front of the crystal growth, which solves the problem of high inclusions in methods such as powder metallurgy, sintering, and direct casting, and hot rolling cannot eliminate the inclusion problem; at the same time, the melt and the substrate are directly fused and bitten, which solves the problem of insufficient mechanical strength of the contact surface between the substrate and the composite layer in methods such as powder metallurgy, direct casting, and rolling.

[0030] 5. According to the Bridgman method for preparing a bimetallic composite plate of the present application, the prepared bimetallic composite plate has uniform composition, a narrow temperature zone width, and an easy-to-control high-temperature liquid phase. The finally prepared bimetallic composite plate has a flat and smooth surface and can be used by simply cutting the tail, eliminating the hot rolling and grinding processes, and has high economic value.

[0031] 6. In powder metallurgy, people often use vibration to achieve high packing density of powder, and then pressurize to obtain high-density green body; in sintering method, similar to powder metallurgy, the composition is relatively uniform; direct melting and pouring can obtain high density. However, as mentioned above, each method is difficult to achieve high pressure in large flat plates; the sintering method cannot obtain high density due to insufficient liquid phase; direct liquid casting is difficult to control thickness and range, and the composition is easy to segregate. The welding method is inefficient and the surface quality is poor; the rolling joint surface is difficult to ensure quality.

[0032] The preparation method of the present application solves the pressure problem of powder metallurgy and can manufacture large plate sizes; solves the component segregation of liquid phase casting and the difficulty in controlling the size; solves the low density problem of the sintering method; solves the poor surface quality and low efficiency of the welding method; and solves the problem of the difficult control of the bonding surface of the direct rolling method. The preparation method has the advantages of uniformity of components of powder metallurgy and sintering method, high density of liquid phase casting method and welding method, and smooth surface of rolling method, overcomes many problems caused by oxidation of the bonding interface during rolling, overcomes the problem of large cold rolling composite rolling force, and overcomes the shortcomings of explosion-rolling method and sintering method. Finally, the present application adopts regional sintering to overcome the problem of large-area direct sintering and difficult control of liquid phase flow. At the same time, the equipment investment is small, the heating power is low, and it can be easily produced in small and medium-sized factories. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0034] Figure 1 The full spectrum component analysis result of the spectrometer after sintering of the region 3# of the composite plate involved in the embodiment of the present application;

[0035] Figure 2 This is a photo of the cladding surface of the composite panel 3# involved in the embodiment of the present application;

[0036] Figure 3 This is a cross-sectional photo of the composite plate 3# involved in the embodiment of the present application;

[0037] Figure 4 This is a cross-sectional photo of a comparative composite board 1# involved in an embodiment of the present application;

[0038] Figure 5 This is a photograph of the cladding surface of the comparative composite panel 2# involved in the embodiment of the present application. DETAILED DESCRIPTION

[0039] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0040] Unless otherwise defined, all professional and scientific terms used herein have the same meanings as those familiar to those skilled in the art. The reagents or raw materials used in the present invention can be purchased through conventional channels. Unless otherwise specified, the reagents or raw materials used in the present invention are used in a conventional manner in the art or in accordance with the product instructions. In addition, any method and material similar or equivalent to the described content can be applied to the method of the present invention. The preferred implementation methods and materials in this patent are for demonstration purposes only.

[0041] In this embodiment, auxiliary operations such as leveling, rust removal, oil removal, roughening, and compaction of the metal substrate are all performed according to conventional operations in the field using conventional parameters. The metal powder granulation is prepared using a metal mixing and mixing granulator, and the cooling gas is a commercially available conventional protective gas.

[0042] Example 1 Composite board 1#

[0043] The metal substrate of composite plate 1# is 304 type stainless steel plate, which has a melting point of 1400°C. The metal powder of the cladding plate is aluminum silicon alloy powder containing 5% Si. After measurement, it was found that the aluminum silicon alloy component will completely melt at 660°C.

[0044] The preparation method comprises the following steps:

[0045] (1) Straighten the stainless steel plate, remove rust, oil and roughen the top surface, clean it and set it aside;

[0046] (2) weighing aluminum powder and silicon powder, mixing and granulating, pouring the aluminum-silicon alloy powder onto the surface of the stainless steel substrate cleaned in step (1), vibrating it, and smoothing it;

[0047] (3) The stainless steel substrate loaded with aluminum-silicon alloy mixed particles in step (2) is horizontally sent into a regional sintering furnace, and is protected by inert gas nitrogen. It is heated to a controlled liquefaction sintering temperature of 660° C., a temperature zone width of 10 cm, and gradually passes through the regional high temperature of 660° C. at a speed of 50 cm / h;

[0048] (4) Cooling gas is blown to the stainless steel substrate at the bottom of the sintering furnace outlet in the step (3), and the other side is naturally cooled to obtain composite plate 1#.

[0049] Example 2 Composite board 2#

[0050] The metal substrate of composite plate 2# is made of 304 stainless steel plate, which has a melting point of 1400°C. The metal powder of the cladding plate is made of copper-silicon alloy powder containing 8% Si. After measurement, it was found that the copper-silicon alloy component will completely melt at 1000°C.

[0051] The preparation method comprises the following steps:

[0052] (1) Straighten the stainless steel plate, remove rust, oil and roughen the top surface, clean it and set it aside;

[0053] (2) Weighing and mixing copper powder and silicon powder to form granules, pouring the copper-silicon alloy powder onto the surface of the stainless steel substrate cleaned in step (1), vibrating it, and smoothing it;

[0054] (3) The stainless steel substrate loaded with copper-silicon alloy mixed particles in step (2) is horizontally fed into a regional sintering furnace, and is protected by inert gas nitrogen, and is heated to a controlled liquefaction sintering temperature of 1000° C., a temperature zone width of 10 cm, and gradually passes through a regional high temperature of 1000° C. at a speed of 30 cm / h;

[0055] (4) Cooling gas is blown to the stainless steel substrate at the bottom of the sintering furnace outlet in step (3), and the other side is naturally cooled to obtain composite plate 2#.

[0056] Example 3 Composite board 3#

[0057] The metal substrate of composite plate 3# is Q235 steel plate, and the metal powder of the cladding plate is ferrochrome powder, specifically ferrochrome powder containing 3.6% C and 13% Cr. After measurement, the alloy composition will be completely melted at 1215°C.

[0058] The preparation method comprises the following steps:

[0059] (1) Straighten the Q235 steel plate, remove rust, oil and roughen the top surface, clean it and set it aside;

[0060] (2) Weighing and mixing various powders to form granules, pouring the alloy powder onto the surface of the Q235 steel plate cleaned in step (1), vibrating it, and smoothing it;

[0061] (3) The Q235 steel plate loaded with chromium-iron alloy mixed particles in step (2) is horizontally fed into a zone sintering furnace, and is protected by an inert gas nitrogen, and is heated to a controlled liquefaction sintering temperature of 1225° C., a temperature zone width of 50 cm, and is gradually passed through the zone high temperature of 1225° C. at a speed of 50 cm / h;

[0062] (4) Cooling gas is blown to the Q235 steel plate at the bottom of the sintering furnace outlet in step (3), and the other side is naturally cooled to obtain composite plate 3#.

[0063] pass Figure 1 The data show that the cladding panels prepared by the method defined in this application have good composition consistency. Figure 2 This is a photo of the cladding surface of the composite board 3#. Figure 3 This is a cross-sectional photo of composite plate 3#. It can be seen that the bimetallic composite plate 3# prepared in Example 3 has high density, no obvious shrinkage holes, a clear bonding interface, which basically forms a line, no obvious ablation of the substrate, a smooth surface of the bimetallic plate, and the Rockwell hardness of the chromium-iron alloy plate surface is measured to be HRC55.

[0064] Comparative Example 1 Comparative Composite Board 1#

[0065] The difference between Comparative Example 1 and Example 3 is that: in Comparative Example 1, the sintering temperature is 1225° C. and directly kept at this temperature for 1 hour, and then cooled naturally in the furnace.

[0066] Figure 4 By comparing the cross-sectional photo of composite plate 1#, it can be seen that it has obvious pores and shrinkage cavities, which can only be solved by vacuum sintering or subsequent hot rolling process. The embodiment of the present application does not require subsequent process to obtain a dense bimetallic plate.

[0067] Comparative Example 2 Comparative Composite Board 2#

[0068] The difference between Comparative Example 2 and Example 3 is that the temperature zone width of Comparative Example 2 is 2 cm, and the sintering is completed by gradually passing through the regional high temperature at a speed of 150 cm / h. Figure 5 For comparison of the coating surface photos of composite board 2#, due to the narrow temperature zone width, too fast moving speed and insufficient insulation time, the coating powder was not completely melted, resulting in hardening.

[0069] Experimental Example: Surface Rockwell Hardness Test

[0070] Experimental method: According to GB / T8263-2010, the performance of bimetallic plates only needs to be tested for Rockwell hardness HRC. Taking composite plate 3# as an example, 3 plates of composite plate 3# are tested, 10 points are scored, and the results are averaged.

[0071] For the comparison of composite board 1#, 3 boards were taken for testing, 10 points were marked, and the results were averaged.

[0072]

[0073] Based on the above data and pictures, it can be seen that the Rockwell hardness value of the composite plate prepared by the preparation method specified in the present application is high, while the comparison composite plate 1# has a large number of pores and the tested hardness value is low. The comparison composite plate 2# was not sintered and no hardness test was performed.

[0074] The above is only the embodiment of the present application, and the protection scope of the present application is not limited by these specific embodiments, but is determined by the claims of the present application. For those skilled in the art, the present application can have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the technical ideas and principles of the present application should be included in the protection scope of the present application.

Claims

1. A method for preparing a bimetallic composite plate by a Bridgman method, characterized in that: The bimetallic composite plate is composed of a metal substrate and a cladding plate. The cladding plate is obtained by sintering metal powder granulation, and includes the following steps: (1) Correct the metal substrate to make it flat, remove rust, oil and roughen the top surface in turn, clean it and set it aside; (2) Mix the metal powders and granulate them, pour them on the top surface of the metal substrate, vibrate them and smooth them; (3) The metal substrate with the metal mixed particles on the top surface is horizontally sent into the regional sintering furnace, and inert gas protection is introduced, and it is heated to the liquefaction sintering temperature of the metal particles. The width of the temperature zone is 10-50 cm, and it gradually passes through the regional high temperature at a speed of 30-200 cm / h to complete the sintering; (4) Blowing cooling gas to the metal substrate at the bottom of the regional sintering furnace outlet, and the other side is naturally cooled to obtain the bimetallic composite plate; The sintering temperature of the regional sintering furnace in step (3) is 10-50°C higher than the melting temperature of the metal powder for preparing the cladding plate, and needs to reach at least 90% of the melting amount of the powder; In step (2), the metal powder is evenly spread, and the thickness of the cladding plate metal mixed particles added is 0.3-3 times the thickness of the metal substrate; The molten metal of the cladding plate crystallizes along the horizontal direction of the metal substrate, is gradually pushed out from the high temperature zone, the liquid phase begins to cool, the molten metal begins to nucleate and crystallize, and grows in the opposite direction of the plate movement. The width of the metal substrate is large, forming multiple crystals that grow side by side forward.

2. The preparation method according to claim 1, characterized in that: The metal substrate is one of a copper plate, a steel plate, a tungsten alloy plate and a molybdenum alloy plate.

3. The preparation method according to claim 1, characterized in that: The metal powder of the cladding plate is one of aluminum silicon alloy powder, copper silicon alloy powder and chromium iron alloy powder.

4. The preparation method according to claim 1, characterized in that: The melting point of the metal powder of the cladding plate is lower than the melting point of the metal substrate by more than 100°C.

5. The preparation method according to claim 1, characterized in that: The regional sintering furnace adopts medium or high frequency induction heating or adopts one of resistance wire, silicon carbon rod and silicon molybdenum rod for heating.

6. The preparation method according to claim 1, characterized in that: The inert gas in step (3) is nitrogen.

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