Method for preparing explosively welded composite plate of medium-entropy alloy and stainless steel

Abstract

The present invention discloses a method for preparing a composite plate of explosively welded medium-entropy alloy and stainless steel, which belongs to the field of metal-based composite material processing. The preparation method specifically comprises: grinding the medium-entropy alloy and stainless steel to remove surface oil and oxides; using a low-carbon steel anvil as a backing plate, stainless steel as a substrate, a medium-entropy alloy as a composite plate, corrugated cardboard as an explosive and a buffer layer of the composite plate, and using a low-detonation-velocity, high-strength mixed explosive to achieve metallurgical connection between the medium-entropy alloy plate and the stainless steel plate. The obtained composite plate has an interface bonding rate greater than 98.8%, a yield strength greater than 620MPa, a tensile strength greater than 735MPa, an elongation after fracture greater than 40%, and an interface shear strength greater than 300MPa. The process of the present invention is simple and convenient, and is suitable for industrial production.

Description

Technical Field

[0001] The invention relates to the field of metal composite material processing, and specifically provides a method for preparing a medium-entropy alloy and stainless steel explosively welded composite plate, belonging to the field of material forming. Background Art

[0002] Medium-entropy alloys (MEAs) are a new type of high-performance structural and functional integrated metal material that has emerged in recent years. Compared with traditional alloys, MEAs have high hardness, high strength, excellent high-temperature oxidation resistance, corrosion resistance, and radiation resistance, and therefore have extremely broad application prospects. As a representative of MEAs, the equiatomic ratio CoCrNi alloy is currently recognized as an alloy with excellent mechanical properties at both room temperature and low temperature. In addition, compared with other MEAs and high-entropy alloys, CoCrNi MEAs also exhibit better corrosion resistance in HCl solution. However, the high Co content in this alloy leads to a significant increase in its manufacturing cost, which to some extent limits its widespread application.

[0003] 316L stainless steel is one of the most common structural materials. Due to its excellent mechanical properties and low price, it has been widely used in various fields of industry and daily life. However, as modern industry's requirements for material performance become increasingly stringent, single metal materials are gradually unable to meet the needs of many fields. Therefore, people are paying more and more attention to double-layer or multi-layer dissimilar metal composite materials.

[0004] Composites of CoCrNi medium-entropy alloys with 316L stainless steel to produce layered composites not only leverage the performance advantages of CoCrNi medium-entropy alloys but also leverage the low-cost advantages of 316L stainless steel, significantly promoting the wider application of CoCrNi medium-entropy alloys. Explosive welding, as an important method for preparing dissimilar metal layered composites, has been applied to a variety of materials, including copper / aluminum, titanium / aluminum, titanium / steel, titanium / stainless steel, nickel / copper, and nickel / stainless steel. However, as an isomeric, multi-component alloy, CoCrNi medium-entropy alloys exhibit a disordered atomic arrangement and lack of primary alloying elements, resulting in completely different plastic deformation mechanisms, as well as those induced during explosive composites, compared to conventional pure metals and alloys such as aluminum, copper, titanium, and nickel, as well as aluminum alloys, copper alloys, titanium alloys, carbon steel, and stainless steel. Therefore, there is currently no experience or reports on explosive welding production technologies for CoCrNi medium-entropy alloys and 316L stainless steel. Therefore, developing a technology that satisfies the explosive welding requirements of CoCrNi medium-entropy alloys and 316L stainless steel is a critical issue that urgently needs to be addressed in the field of composite plate manufacturing technology. Summary of the Invention

[0005] In response to the shortcomings of the prior art, the present invention aims to provide a method for preparing a composite plate made of explosively welded medium-entropy alloy and stainless steel. The composite plate comprises a medium-entropy alloy of CoCrNi with an equiatomic ratio, and 316L stainless steel. The composite plate is obtained by explosive welding. The explosive welding process uses a low-carbon steel anvil as a backing plate, stainless steel as a substrate, the medium-entropy alloy as a composite plate, and corrugated cardboard as a buffer layer between the explosive and the composite plate. A low-detonation-velocity, high-intensity mixed explosive is then used to achieve metallurgical connection. The process is simple and convenient, making it suitable for industrial production.

[0006] In order to achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0007] The present invention discloses a method for preparing a medium-entropy alloy and stainless steel explosively welded composite plate. The method comprises the following steps: annealing the medium-entropy alloy plate and solution treating the stainless steel plate; then laying sand, anvils, stainless steel plates, support columns, medium-entropy alloy plates, corrugated paper, and explosives in sequence from bottom to top on an explosion field; and then performing explosive welding to obtain the medium-entropy alloy and stainless steel explosively welded composite plate. The explosive has a detonation velocity of 1600-2100 m / s and a velocities of 15-18 mm.

[0008] In the present invention, the medium-entropy alloy plate is first annealed and the stainless steel plate is solution treated so that they both have good plasticity, ensuring that the explosion process can easily achieve metallurgical bonding of the materials without cracking, then the stainless steel plate is used as the base plate and the medium-entropy alloy plate is used as the composite plate, and finally low-detonation velocity and high-intensity explosives are used for explosion welding to obtain an explosion with metallurgical bonding, wherein the low detonation velocity can control the amplitude of the composite interface waveform, forming a small wave bonding interface, and improving the bonding strength, while the high-intensity explosive can cause the base plate and the composite plate to undergo severe work hardening during the explosion process, thereby improving the strength of the material and compensating for the material strength loss caused by complete annealing before the explosive composite, thereby obtaining a medium-entropy alloy and stainless steel explosion-welded composite plate with excellent mechanical properties in the present invention.

[0009] As a preferred solution, the stainless steel in the stainless steel plate is 316L, and the medium entropy alloy in the medium entropy alloy plate is a CoCrNi medium entropy alloy, wherein Co, Cr and Ni are in equal atomic ratios.

[0010] As a preferred embodiment, the length × width × thickness of the stainless steel plate is: (400~1000) mm × (200~500) mm × (5~20) mm; the length × width × thickness of the medium entropy alloy plate is: (410~1010) mm × (210~510) mm × (1.5~3) mm, and the length and width of the medium entropy alloy plate are both greater than the length and width of the stainless steel plate.

[0011] In the present invention, the high-cost medium-entropy alloy plate is selected as a thin plate, and the low-cost stainless steel plate is used as a thick plate. During the explosive composite process, the stainless steel plate is used as the base plate and the medium-entropy alloy plate is used as the composite plate, which has better support.

[0012] As a preferred solution, the surface roughness Ra of the medium entropy alloy plate and the stainless steel plate is ≤3 μm. In actual operation, the surface of the base plate and the composite plate is polished before use to remove surface oil and oxides to ensure that the surface roughness Ra is ≤3 μm.

[0013] As a preferred solution, the medium-entropy alloy plate is annealed at a temperature of 1000-1100°C for 1-2 hours. By completely softening the medium-entropy alloy plate within these parameters, the alloy possesses good plasticity, ensuring that the explosion process easily achieves metallurgical bonding without cracking.

[0014] As a preferred solution, the stainless steel plate is subjected to a solution treatment at a temperature of 1100-1150° C. for 1.5-2 hours. In actual operation, after the solution treatment is completed, a rapid cooling treatment such as water cooling is performed.

[0015] Through the above-mentioned solution treatment, the stainless steel plate is softened and has good plasticity, ensuring that the metallurgical bonding of the materials can be easily achieved without cracking during the explosion process.

[0016] In industrial applications, a hard soil site needs to be selected as a test site, and debris must be removed and leveled to form an explosion site. Then, a layer of 8-10mm sand is laid as the foundation.

[0017] As a preferred solution, the thickness of the sand is 8 to 10 mm.

[0018] As a preferred solution, the anvil is made of low carbon steel and has a thickness of 40-60 mm.

[0019] In the present invention, since high-intensity explosives are used, the explosion process not only has a greater impact on the base plate and the composite plate, but also has a greater impact on the anvil plate. Therefore, by placing a low-carbon steel anvil plate with a larger thickness and better toughness under the soft base plate, serious bending and deformation of the composite plate during the explosion process can be avoided.

[0020] As a further preferred embodiment, the anvil is 2000-3000 mm long and 1000-2000 mm wide. In actual industrial applications, the anvil should be parallel to the ground and not tilted. The upper surface of the anvil should be cleaned and kept smooth, and the stainless steel plate should be placed in the center of the anvil.

[0021] As a preferred solution, support columns are arranged at the four corners of the surface of the stainless steel plate, and then the medium entropy alloy plate is placed above the support columns to ensure that the center position of the medium entropy alloy plate and the center position of the stainless steel plate are on the same axis, and the four sides of the medium entropy alloy plate are parallel to the four sides of the stainless steel plate.

[0022] Further preferably, the support column has a diameter of 9-10 mm, preferably 10 mm, and a height of 5-8 mm, preferably 6 mm.

[0023] As a preferred solution, wooden strips are used to surround the medium entropy alloy plate on all sides, and the upper surface of the wooden strips is controlled to be higher than the surface of the medium entropy alloy plate to serve as an explosive pool. The depth of the explosive pool is 50-70 mm.

[0024] As a preferred embodiment, the thickness of the corrugated paper is 5-6 mm. In industrial applications, the corrugated paper is placed in an explosive pool to isolate the explosive from direct contact with the composite board, and to act as a buffer and protect the board surface during the explosion. The explosive is then evenly spread on the corrugated paper.

[0025] As a preferred embodiment, the explosives are composed of the following components by mass percentage: 50-60% antimony-free rock ammonium nitrate explosive, 10-15% magnesium carbonate powder, 5-10% silicon carbide powder, 5-10% perlite powder, 5-10% charcoal powder, and 5-8% nickel powder.

[0026] Generally, the detonation velocity of explosives is high and the force is also large; the detonation velocity is low and the force is small, but the detonation velocity is related to the released energy and temperature rise. Although the force is also related to energy, it is more related to the impact force. The explosive components of the present invention use antimony-free rock ammonium nitrate as the base explosive. Adding magnesium carbonate and silicon carbide powder to the base explosive can reduce the detonation velocity of the explosive. Adding perlite powder and charcoal powder can increase the fluffiness, which is conducive to detonation. Adding nickel powder can increase the force of the explosive, thereby obtaining an explosive with low detonation velocity and high force. When the explosive components of the present invention are used for production, the low detonation velocity feature can ensure that the composite interface is a small wavy bonding interface, thereby improving the bonding strength; and the high force feature can ensure that the base plate and the composite plate undergo severe work hardening during the explosion process, thereby compensating for the material strength loss caused by complete annealing before explosive composite.

[0027] For industrial applications, the explosives must be prepared, dried, and evenly mixed within one hour before use. The mixture should then be sieved through an 80-mesh sieve, and the -80-mesh mixed powder should be selected as the explosive to be used. When using, add 5% water by volume to the mixed explosives and mix thoroughly before laying.

[0028] As a preferred solution, the density of the explosive is 0.75~0.9g / cm 3 .

[0029] As a preferred solution, a detonator is installed in the explosives, positioned centrally along the short sides of the stainless steel and medium-entropy alloy plates. A lead is then connected to the detonator, which is then connected to a remote detonator. The detonator is then detonated via the lead, completing the explosive welding process and producing a medium-entropy alloy and stainless steel explosively welded composite plate. The inventors have discovered that placing the detonator on the short sides improves yield.

[0030] In a further preferred embodiment, three quarters of the detonator is buried in the explosive.

[0031] In industrial production, the board surface after explosive compounding needs to be cleaned and leveled, and the cracked and collapsed parts of the edges need to be removed. Finally, ultrasonic testing is used to ensure that the entire board surface is well bonded.

[0032] The medium-entropy alloy and stainless steel explosively welded composite plate prepared by the present invention has an interface bonding rate greater than 98.8%, a yield strength greater than 620 MPa, a tensile strength greater than 735 MPa, an elongation after fracture greater than 40%, and an interface shear strength greater than 300 MPa.

[0033] The interface bonding rate obtained under the optimal process is 99.2%, the yield strength is 635MPa, the tensile strength is 755MPa, the elongation after fracture is 42%, and the interface shear strength is 318MPa.

[0034] Principles and advantages

[0035] This invention achieves metallurgical bonding of a CoCrNi medium-entropy alloy and 316L stainless steel through explosive welding, providing a method for preparing high-performance bimetallic composite plates suitable for industrial production. The selection of various explosive welding parameters plays a crucial role in the final composite plate's performance. Through numerous experiments, the present invention has identified optimal explosive welding process parameters for producing excellent-performance CoCrNi medium-entropy alloy and 316L stainless steel composite plates.

[0036] Before explosive welding, the present invention performs a complete annealing treatment on the selected CoCrNi medium entropy alloy and 316L stainless steel, so that the alloy has good plasticity, ensuring that the metallurgical bonding of the materials is easy to achieve and no cracking during the explosion process. In particular, when high-strength explosives are used in the present invention, the plate to be composited must be pretreated to a suitable state. In industrial production, a low-carbon steel anvil with a large thickness and good toughness is placed under the soft substrate to avoid serious bending deformation of the composite plate during the explosion process. In addition, the use of low-detonation-velocity explosives can control the amplitude of the composite interface waveform and form a small-wave bonding interface. The selection of high-strength explosives can cause severe work hardening of the substrate and composite plate during the explosion process, improve the strength of the material, and make up for the material strength loss caused by complete annealing before explosive composite. Therefore, this technology is designed specifically to utilize the excellent work hardening capabilities of the soft CoCrNi medium entropy alloy and 316L stainless steel.

[0037] The present invention obtains a composite plate of medium-entropy alloy and stainless steel for the first time through explosive welding. Under the optimal process conditions, the interface bonding rate of the composite plate obtained is 99.2%, the yield strength is 635 MPa, the tensile strength is 755 MPa, the elongation after fracture is 42%, and the interface shear strength is 318 MPa. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 Schematic diagram of the process structure for explosive welding of CoCrNi medium entropy alloy and 316L stainless steel.

[0039] Figure 2 Explosive welding samples of CoCrNi medium entropy alloy and 316L stainless steel.

[0040] Figure 3 The interface morphology of the explosively welded composite plate of the medium entropy alloy and stainless steel obtained in Example 1 shows a small wavy interface. DETAILED DESCRIPTION

[0041] The following are preferred embodiments of the present invention, but not all embodiments. Without departing from the principle of this process innovation, any equivalent process transformation made by utilizing the contents of the present invention specification, or directly or indirectly applied in other related technical fields, shall be deemed to be within the scope of patent protection of this invention.

[0042] Example 1

[0043] Selecting equiatomic ratio CoCrNi medium entropy alloy sheet and 316L stainless steel sheet as raw materials, firstly, the CoCrNi medium entropy alloy sheet was subjected to complete softening annealing at 1000℃ / 2h, and the 316L stainless steel was subjected to solution treatment and rapid cooling at 1100℃ / 2h. Then, the following steps were followed:

[0044] S1. Cut a stainless steel plate and a CoCrNi medium-entropy alloy plate with dimensions of 400 mm (length × width × thickness) by 200 mm by 5 mm and 410 mm (width × thickness) by 210 mm by 1.5 mm, respectively. Polish the surfaces of the two alloy plates with an abrasive belt to remove surface oil and oxides.

[0045] S2. Select a hard soil site as the blasting site, remove debris from the site, level it, and then lay a layer of 8-10mm sand as the foundation.

[0046] S3. Place a low-carbon steel anvil with dimensions of 1000mm x 2000mm x 40mm parallel to the ground on the foundation and clean its surface.

[0047] S4. Place a 5 mm thick stainless steel plate as a substrate in the center of the anvil.

[0048] S5. Place four aluminum alloy columnar support columns with a diameter of 10 mm and a height of 6 mm at the four corners of the stainless steel plate.

[0049] S6. Place the CoCrNi medium-entropy alloy plate on the support column, ensuring that the center of the medium-entropy alloy and the center of the stainless steel substrate are on the same axis, and the four sides are parallel to the four sides of the substrate.

[0050] S7. Surround the medium-entropy alloy with wooden strips, with the upper surface of the wooden strips 50 mm higher than the surface of the medium-entropy alloy, to form an explosive pool with a depth of 50 mm.

[0051] S8. Lay a layer of 5mm corrugated paper at the bottom of the explosives pool to isolate the explosives from direct contact with the composite plate. At this time, the depth of the explosives pool is 45mm.

[0052] S9. Evenly spread the homemade low-detonation-velocity and high-strength mixed explosive in the explosive pool above the corrugated paper, and arrange the detonating cap at the center of one of the short sides to ensure that three-quarters of the detonating cap is buried in the explosive. In this embodiment, the composition of the explosive is as follows by mass percentage: 50% antimony-free rock ammonium nitrate explosive, 15% magnesium carbonate powder, 10% silicon carbide powder, 10% perlite powder, 10% charcoal powder, and 5% nickel powder. All powders are dried and mixed evenly within 1 hour before use, and then sieved with an 80-mesh sieve, and the -80-mesh mixed powder is selected as the stand-by explosive. Before use, add 5% by volume of water to the mixed explosive and mix it evenly. The detonation velocity of the mixed explosive is 1600m / s, the strength is 15mm, and the density is 0.75g / cm 3 .

[0053] S10. Detonate the detonator with a detonator through the connecting wire to obtain a medium-entropy alloy and stainless steel composite plate.

[0054] The resulting explosively welded plates were surface cleaned, leveled, and their cracked and collapsed edges removed, and finally ultrasonically inspected.

[0055] The interface bonding rate of the medium-entropy alloy and stainless steel explosively welded composite plate prepared by this process is 99%, the yield strength is 625 MPa, the tensile strength is 742 MPa, the elongation after fracture is 46.2%, and the interface shear strength is 312 MPa.

[0056] Example 2

[0057] Selecting equiatomic ratio CoCrNi medium entropy alloy sheet and 316L stainless steel sheet as raw materials, firstly, the CoCrNi medium entropy alloy sheet was subjected to complete softening annealing at 1000℃ / 2h, and the 316L stainless steel was subjected to solution treatment and rapid cooling at 1100℃ / 2h. Then, the following steps were followed:

[0058] S1. Cut a stainless steel plate and a CoCrNi medium-entropy alloy plate with dimensions of 600 mm (length × width × thickness) × 300 mm (length × width × thickness) × 15 mm, respectively. Polish the surfaces of the two alloy plates with an abrasive belt to remove surface oil and oxides.

[0059] S2. Select a hard soil site as the blasting site, remove debris from the site, level it, and then lay a layer of 8-10mm sand as the foundation.

[0060] S3. Place a low-carbon steel anvil with dimensions of 2000mm x 2500mm x 50mm parallel to the ground on the foundation and clean its surface.

[0061] S4. Place a 15 mm thick stainless steel plate as a substrate in the center of the anvil.

[0062] S5. Place four aluminum alloy columnar support columns with a diameter of 10 mm and a height of 6 mm at the four corners of the stainless steel plate.

[0063] S6. Place the CoCrNi medium-entropy alloy plate on the support column, ensuring that the center of the medium-entropy alloy and the center of the stainless steel substrate are on the same axis, and the four sides are parallel to the four sides of the substrate.

[0064] S7. Surround the medium-entropy alloy with wooden strips, with the upper surface of the wooden strips 60 mm higher than the surface of the medium-entropy alloy, to form an explosive pool with a depth of 60 mm.

[0065] S8. Lay a layer of 5mm corrugated paper at the bottom of the explosives pool to isolate the explosives from direct contact with the composite plate. At this time, the depth of the explosives pool is 55mm.

[0066] S9. Evenly spread the homemade low-detonation-velocity and high-strength mixed explosive in the explosive pool above the corrugated paper, and arrange the detonating cap at the center of one of the short sides to ensure that three-quarters of the detonating cap is buried in the explosive. In this embodiment, the composition of the explosive is as follows by mass percentage: 54% antimony-free rock ammonium nitrate explosive, 10% magnesium carbonate powder, 10% silicon carbide powder, 10% perlite powder, 10% charcoal powder, and 6% nickel powder. All powders are dried and mixed evenly within 1 hour before use, and then sieved with an 80-mesh sieve, and the -80-mesh mixed powder is selected as the stand-by explosive. Before use, add 5% by volume of water to the mixed explosive and mix it evenly. The detonation velocity of the mixed explosive is 1800m / s, the strength is 16mm, and the density is 0.80g / cm 3 .

[0067] S10. Detonate the detonator with a detonator through the connecting wire to obtain a medium-entropy alloy and stainless steel composite plate.

[0068] The resulting explosively welded plates were surface cleaned, leveled, and their cracked and collapsed edges removed, and finally ultrasonically inspected.

[0069] The interface bonding rate of the medium-entropy alloy and stainless steel explosively welded composite plate prepared by this process is 99.2%, the yield strength is 635 MPa, the tensile strength is 755 MPa, the elongation after fracture is 42%, and the interface shear strength is 318 MPa.

[0070] Example 3

[0071] Selecting equiatomic ratio CoCrNi medium entropy alloy sheet and 316L stainless steel sheet as raw materials, firstly, the CoCrNi medium entropy alloy sheet was subjected to complete softening annealing at 1000℃ / 2h, and the 316L stainless steel was subjected to solution treatment and rapid cooling at 1100℃ / 2h. Then, the following steps were followed:

[0072] S1. Cut a stainless steel plate and a CoCrNi medium-entropy alloy plate with dimensions of 1000 mm (length, width, and thickness) by 500 mm (length, width, and thickness) by 20 mm (width, width, and thickness) and 1010 mm (width, width, and thickness) by 510 mm (width, width, and thickness) by 3 mm (height, width, and thickness). Polish the surfaces of the two alloy plates with an abrasive belt to remove surface oil and oxides.

[0073] S2. Select a hard soil site as the blasting site, remove debris from the site, level it, and then lay a layer of 8-10mm sand as the foundation.

[0074] S3. Place a low-carbon steel anvil with dimensions of 2000mm x 3000mm x 60mm parallel to the ground on the foundation and clean its surface.

[0075] S4. Place a 20 mm thick stainless steel plate as a substrate in the center of the anvil.

[0076] S5. Place four aluminum alloy columnar support columns with a diameter of 10 mm and a height of 6 mm at the four corners of the stainless steel plate.

[0077] S6. Place the CoCrNi medium-entropy alloy plate on the support column, ensuring that the center of the medium-entropy alloy and the center of the stainless steel substrate are on the same axis, and the four sides are parallel to the four sides of the substrate.

[0078] S7. Surround the medium-entropy alloy with wooden strips, with the upper surface of the wooden strips 70 mm higher than the surface of the medium-entropy alloy, to form an explosive pool with a depth of 70 mm.

[0079] S8. Lay a layer of 5mm corrugated paper at the bottom of the explosives pool to isolate the explosives from direct contact with the composite plate. At this time, the depth of the explosives pool is 65mm.

[0080] S9. Evenly spread the homemade low-detonation-velocity and high-strength mixed explosive in the explosive pool above the corrugated paper, and arrange the detonating cap at the center of one of the short sides to ensure that three-quarters of the detonating cap is buried in the explosive. In this embodiment, the composition of the explosive is as follows by mass percentage: 60% antimony-free rock ammonium nitrate explosive, 15% magnesium carbonate powder, 5% silicon carbide powder, 5% perlite powder, 7% charcoal powder, and 8% nickel powder. All powders are dried and mixed evenly within 1 hour before use, and then sieved with an 80-mesh sieve, and the -80-mesh mixed powder is selected as the stand-by explosive. Before use, add 5% by volume of water to the mixed explosive and mix it evenly. The detonation velocity of the mixed explosive is 2100m / s, the strength is 18mm, and the density is 0.90g / cm 3 .

[0081] S10. Detonate the detonator with a detonator through the connecting wire to obtain a medium-entropy alloy and stainless steel composite plate.

[0082] The resulting explosively welded plates were surface cleaned, leveled, and their cracked and collapsed edges removed, and finally ultrasonically inspected.

[0083] The interface bonding rate of the medium-entropy alloy and stainless steel explosively welded composite plate prepared by this process is 98.8%, the yield strength is 622 MPa, the tensile strength is 731 MPa, the elongation after fracture is 40.3%, and the interface shear strength is 304 MPa.

[0084] Example 4

[0085] Selecting equiatomic ratio CoCrNi medium entropy alloy sheet and 316L stainless steel sheet as raw materials, firstly, the CoCrNi medium entropy alloy sheet was subjected to complete softening annealing at 1000℃ / 2h, and the 316L stainless steel was subjected to solution treatment and rapid cooling at 1100℃ / 2h. Then, the following steps were followed:

[0086] S1. Cut a stainless steel plate and a CoCrNi medium-entropy alloy plate with dimensions of 750 mm (length × width × thickness) by 400 mm (length × width × thickness) by 10 mm. Then, use an abrasive belt to polish the surfaces of the two alloy plates to remove surface oil and oxides.

[0087] S2. Select a hard soil site as the blasting site, remove debris from the site, level it, and then lay a layer of 8-10mm sand as the foundation.

[0088] S3. Place a low-carbon steel anvil parallel to the ground with dimensions of 1500mm x 2000mm x 50mm on the foundation and clean its surface.

[0089] S4. Place a 10 mm thick stainless steel plate as a substrate in the center of the anvil.

[0090] S5. Place four aluminum alloy columnar support columns with a diameter of 10 mm and a height of 6 mm at the four corners of the stainless steel plate.

[0091] S6. Place the CoCrNi medium-entropy alloy plate on the support column, ensuring that the center of the medium-entropy alloy and the center of the stainless steel substrate are on the same axis, and the four sides are parallel to the four sides of the substrate.

[0092] S7. Surround the medium-entropy alloy with wooden strips, with the upper surface of the wooden strips 65 mm higher than the surface of the medium-entropy alloy, to form an explosive pool with a depth of 65 mm.

[0093] S8. Lay a layer of 5mm corrugated paper at the bottom of the explosives pool to isolate the explosives from direct contact with the composite plate. At this time, the depth of the explosives pool is 60mm.

[0094] S9. Evenly spread the homemade low-detonation-velocity and high-strength mixed explosive in the explosive pool above the corrugated paper, and arrange the detonating cap at the center of one of the short sides to ensure that three-quarters of the detonating cap is buried in the explosive. In this embodiment, the composition of the explosive is as follows by mass percentage: 56% antimony-free rock ammonium nitrate explosive, 15% magnesium carbonate powder, 7% silicon carbide powder, 7% perlite powder, 8% charcoal powder, and 7% nickel powder. All powders are dried and mixed evenly within 1 hour before use, and then sieved with an 80-mesh sieve, and the -80-mesh mixed powder is selected as the stand-by explosive. Before use, add 5% by volume of water to the mixed explosive and mix it evenly. The detonation velocity of the mixed explosive is 2000m / s, the strength is 17mm, and the density is 0.89g / cm 3 .

[0095] S10. Detonating the detonator through the connecting wire and the detonator to obtain a composite plate of the medium-entropy alloy and the stainless steel.

[0096] The resulting explosively welded plates were surface cleaned, leveled, and their cracked and collapsed edges removed, and finally ultrasonically inspected.

[0097] The interface bonding rate of the medium-entropy alloy and stainless steel explosively welded composite plate prepared by this process is 99.1%, the yield strength is 630 MPa, the tensile strength is 726 MPa, the elongation after fracture is 41.6%, and the interface shear strength is 312 MPa.

[0098] Comparative Example 1

[0099] Other conditions were the same as those in Example 1, except that the CoCrNi medium-entropy alloy was not annealed before explosive cladding. That is, the composite plate material was a hard CoCrNi medium-entropy alloy. Since the hard medium-entropy alloy has high strength and poor plasticity, it cannot withstand strong plastic deformation during the explosive cladding process. Therefore, after the explosion, the strong impact force generated by the explosives caused the medium-entropy alloy composite plate to be cracked, and the cladding failed.

[0100] Comparative Example 2

[0101] Other conditions were the same as in Example 1, except that the explosive composition was changed to: 55% antimony-free rock ammonium nitrate explosive, 15% magnesium carbonate powder, 10% silicon carbide powder, 10% perlite powder, and 10% charcoal powder. That is, nickel powder was not added to the explosive. Since nickel serves to increase explosive strength, without nickel powder, the explosive has a low detonation velocity and low strength. Although low strength is beneficial to the surface quality after composite bonding, the low strength does not provide sufficient impact force during the explosion, resulting in a cross-sectional bonding ratio of only 20% after explosive composite bonding.

Claims

1. A method for preparing a composite plate of a medium entropy alloy and stainless steel by explosive welding, characterized in that: The medium entropy alloy plate is annealed, and the stainless steel plate is solution treated. Then, sand, anvils, stainless steel plates, support columns, medium entropy alloy plates, corrugated paper, and explosives are laid in order from bottom to top on the explosion field. Then, explosive welding is performed to obtain a medium entropy alloy and stainless steel explosion-welded composite plate. The detonation velocity of the explosive is 1600-2100 m / s and the intensity is 15-18 mm. The stainless steel in the stainless steel plate is 316L, and the medium entropy alloy in the medium entropy alloy plate is CoCrNi medium entropy alloy, wherein Co, Cr, and Ni are in equal atomic ratios; The length × width × thickness of the stainless steel plate is: 400~1000mm × 200~500mm × 5~20mm; the length × width × thickness of the medium entropy alloy plate is: 410~1010mm × 210~510mm × 1.5~3mm, and the length and width of the medium entropy alloy plate are both greater than the length and width of the stainless steel plate; The surface roughness Ra of the medium entropy alloy plate and the stainless steel plate are both ≤3 μm; The annealing temperature is 1000-1100°C and the annealing time is 1-2 hours; The temperature of the solution treatment is 1100-1150°C, and the time of the solution treatment is 1.5-2 hours; The anvil is made of low carbon steel and has a thickness of 40-60 mm. The explosive comprises the following components by mass percentage: 50-60% antimony-free rock ammonium nitrate explosive, 10-15% magnesium carbonate powder, 5-10% silicon carbide powder, 5-10% perlite powder, 5-10% charcoal powder, and 5-8% nickel powder; The density of the explosive is 0.75~0.9g / cm 3 .

2. The method for preparing a medium entropy alloy and stainless steel explosively welded composite plate according to claim 1, characterized in that: The thickness of the sand is 8-10 mm; The anvil has a length of 2000-3000 mm and a width of 1000-2000 mm.

3. The method for preparing a medium entropy alloy and stainless steel explosively welded composite plate according to claim 1, characterized in that: Arrange support columns at the four corners of the surface of the stainless steel plate, and then place the medium entropy alloy plate on top of the support columns, ensuring that the center position of the medium entropy alloy plate and the center position of the stainless steel plate are on the same axis, and the four sides of the medium entropy alloy plate are parallel to the four sides of the stainless steel plate; The support column has a diameter of 9-10 mm and a height of 5-8 mm.

4. The method for preparing a medium entropy alloy and stainless steel explosively welded composite plate according to claim 1, characterized in that: The medium entropy alloy plate is surrounded by wooden strips, and the upper surface of the wooden strips is controlled to be higher than the surface of the medium entropy alloy plate to serve as an explosive pool. The depth of the explosive pool is 50-70 mm. The thickness of the corrugated paper is 5-6 mm.

5. The method for preparing a medium entropy alloy and stainless steel explosively welded composite plate according to claim 1, characterized in that: A detonator is installed in the explosive, and the detonator is installed at the center position of the short side direction of the stainless steel plate and the medium entropy alloy plate. Then, a lead is connected to the detonator, and finally, the connecting lead is connected to a remote control detonating device. Through the connecting lead, the detonator is detonated with a detonator to complete the explosive welding, thereby obtaining a medium entropy alloy and stainless steel explosively welded composite plate; three-quarters of the detonator is buried in the explosive.

6. The method for preparing a medium entropy alloy and stainless steel explosively welded composite plate according to claim 1, characterized in that: The interface bonding rate of the explosively welded composite plate of the medium-entropy alloy and stainless steel is greater than 98.8%, the yield strength is greater than 620 MPa, the tensile strength is greater than 735 MPa, the elongation after fracture is greater than 40%, and the interface shear strength is greater than 300 MPa.

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