Applications of High-Entropy Alloys, Titanium-Steel Bimetallic Composite Plates and Their Preparation Methods

Abstract

The present invention relates to the application of high-entropy alloys, titanium-steel bimetallic composite plates and their preparation methods, belonging to the technical field of bimetallic composite materials. In the present invention, an AlLiMgSnTi high-entropy alloy is used as a filler metal for welding titanium and steel materials. Since the high-entropy alloy does not contain iron elements, the high-entropy alloy can reduce the mutual diffusion between titanium and iron and effectively inhibit the diffusion of carbon elements in steel into titanium to generate intermetallic compounds, thereby reducing the formation of brittle phases, and further improving the bonding strength, shear strength and corrosion resistance of titanium and steel materials.

Description

Technical Field

[0001] The present invention relates to the application of high-entropy alloys, a titanium-steel bimetallic composite plate and a preparation method thereof, and belongs to the technical field of bimetallic composite materials. Background Art

[0002] When traditional metal plates for buildings are used under daily conditions, their service life generally can meet the design requirements and have good economy. However, with the gradual development of ocean exploitation in China, under relatively humid conditions, due to the corrosion effects of seawater, rainwater, moisture, etc., ordinary steel plates for buildings are severely corroded, and their service life is greatly reduced. Seriously, it may affect production and living safety.

[0003] Titanium and titanium alloys have the advantages of low density, high specific strength, seawater corrosion resistance, etc., and are ideal materials for ocean engineering. However, due to the high cost of titanium, its use as a structural material for buildings in the marine environment is restricted. The titanium-steel corrosion-resistant composite plate is a corrosion-resistant and high-strength composite material with steel as the matrix and titanium alloy covering one or both sides of the steel. It can give full play to the advantages of the two materials, having both the good corrosion resistance of the titanium alloy and the strength and plasticity of the steel as a structural material, extending the service life of the material in the marine corrosion environment, and having a relatively low use cost.

[0004] Since brittle intermetallic compounds such as TiC and Ti-Fe are likely to form at the interface of titanium-steel composite plates. Below the phase transformation temperature of titanium, mainly the carbon element in the steel diffuses towards the titanium side to form TiC; above the phase transformation temperature of titanium, the solubility of carbon in the steel increases. At this time, mainly titanium and iron diffuse mutually to form brittle phases such as TiC, FeTi, and Fe2Ti, deteriorating the properties such as the bonding strength and shear strength of the titanium-steel composite plate and affecting the quality of the titanium-steel composite plate. Therefore, an intermediate layer material needs to be placed between the titanium and steel interfaces to prevent the diffusion of titanium and the mutual diffusion of titanium and iron. Commonly used intermediate layer materials include nickel, niobium, copper, silver, etc., but these materials are relatively expensive. To save costs, industrial pure iron, stainless steel, etc. with extremely low carbon content can also be used as the intermediate layer, but there are still problems with carbon diffusion. Moreover, since industrial pure iron and stainless steel contain a certain amount of carbon, not only the strength is reduced due to the formation of brittle phases, but also a primary battery effect will occur with the steel in the composite plate, and the corrosion resistance will be greatly reduced. Due to the combined effects of the high-entropy effect, atomic retarded diffusion effect, lattice distortion effect, and cocktail effect, high-entropy alloys tend to form simple solid solution structures such as face-centered cubic (FCC), body-centered cubic (BCC), or hexagonal close-packed (HCP), and the high-entropy effect can inhibit the formation of intermetallic compounds. Therefore, high-entropy alloys can also be used as intermediate layer materials to prevent the diffusion of titanium and the mutual diffusion of titanium and iron. Chinese patent document CN 110936680A discloses an intermediate alloy and a composite process for titanium / carbon steel bimetal composite. The composite material is composed of titanium, carbon steel, and an intermediate alloy. The intermediate alloy uses a high-entropy alloy, and the high-entropy alloy is composed of the following five metal elements by atomic percentage: Ga: 5-35%, Cu: 5-35%, Zn: 5-35%, Mn: 5%-35%, Fe: 5%-35%. The composite material is prepared by the method of the intermediate alloy composite technology. Although the metallurgical bonding strength of the titanium / carbon steel bimetal composite material prepared in this patent document has been improved, it still cannot meet the usage requirements. Summary of the Invention

[0005] The purpose of the present invention is to provide an application of an AlLiMgSnTi high-entropy alloy as a filler metal in the welding of titanium materials and steel materials to solve the problem of poor bonding strength existing in current titanium-steel composite materials.

[0006] The second purpose of the present invention is to provide a titanium-steel bimetal composite plate.

[0007] The third purpose of the present invention is to provide a preparation method of a titanium-steel bimetal composite plate.

[0008] To achieve the above purposes, the technical solution adopted for the application of the AlLiMgSnTi high-entropy alloy of the present invention as a filler metal in the welding of titanium materials and steel materials is as follows:

[0009] Application of an AlLiMgSnTi high-entropy alloy as a filler metal in welding of titanium and steel materials

[0010] In the present invention, the AlLiMgSnTi high-entropy alloy is used as a filler metal for welding titanium and steel materials. Since the high-entropy alloy does not contain iron element, the high-entropy alloy can reduce the mutual diffusion between titanium and iron and effectively inhibit the diffusion of carbon element in steel into titanium to generate intermetallic compounds, thereby reducing the formation of brittle phases, and further improving the bonding strength, shear strength and corrosion resistance of titanium and steel materials. The composite plate prepared by the present invention has a high-entropy alloy as a bonding layer, and has good bonding strength, stability and corrosion resistance. The bonding strength of the obtained bimetallic composite material is 260-300 MPa, and the neutral salt spray corrosion can reach 96 h, reaching grade 10.

[0011] The AlLiMgSnTi high-entropy alloy is a solid-solution alloy formed by mixing five main elements (Al, Li, Mg, Sn and Ti), and the atomic fraction of each main element is between 5% and 35%.

[0012] Preferably, the AlLiMgSnTi high-entropy alloy is composed of the following elements in mole percentages: Al: 18-30%, Li: 11-25%, Mg: 5-15%, Sn: 10-18%, and Ti: 30-38%. For example, the AlLiMgSnTi high-entropy alloy is composed of the following elements in mole percentages: Al: 25%, Li: 15%, Mg: 10%, Sn: 15%, and Ti: 35%.

[0013] The present invention places no restrictions on the steel materials, and ordinary steel or stainless steel can be used in the present invention. For example, the steel material is ordinary steel or stainless steel. For example, the steel material is ordinary steel, and the ordinary steel is Q356, 45# steel or 40Cr steel. The steel material is stainless steel, and the stainless steel is martensitic stainless steel or austenitic stainless steel. Further, when the steel material is martensitic stainless steel, the martensitic stainless steel is 2Cr13. Further, when the steel material is austenitic stainless steel, the austenitic stainless steel is 1Cr18Ni9 or 316L.

[0014] The present invention places no restrictions on the titanium materials, and pure titanium materials or titanium alloy materials are applicable to the present invention.

[0015] Preferably, the titanium material is composed of the following elements in mass percentages: Al: 5.50%-6.75%, V: 3.50%-4.50%, Fe: ≤0.30%, C: ≤0.10%, N: ≤0.05%, H: ≤0.015%, O: ≤0.20%, and the balance is Ti.

[0016] Preferably, the titanium material is TC4.

[0017] Preferably, during welding, an AlLiMgSnTi high-entropy alloy is placed between the parts to be welded of the titanium material and the steel material, and then heated to melt the AlLiMgSnTi high-entropy alloy, followed by heat preservation and cooling. During the heat preservation and cooling processes, pressure is applied to squeeze the welded parts of the titanium material and the steel material against each other.

[0018] Preferably, the pressure is 300 - 780 Pa. For example, the pressure is 333 - 778 Pa.

[0019] Preferably, during welding, the AlLiMgSnTi high-entropy alloy is used in the form of powder. Preferably, the thickness of the powder is 300 - 1500 μm. For example, the thickness of the powder is 500 - 1500 μm.

[0020] Preferably, during welding, the method of heating to melt the AlLiMgSnTi high-entropy alloy includes the following steps: First, heat up to 300 - 500 °C for heat preservation, and then heat up to 700 - 900 °C to melt the AlLiMgSnTi high-entropy alloy.

[0021] Preferably, in the method of heating to melt the AlLiMgSnTi high-entropy alloy, the heating rate from 300 - 500 °C is 25 - 70 °C / min. Preferably, in the method of heating to melt the AlLiMgSnTi high-entropy alloy, the heating rate from 300 - 500 °C to 700 - 900 °C is 70 - 130 °C / min. For example, in the method of heating to melt the AlLiMgSnTi high-entropy alloy, the heating rate from 300 - 500 °C to 700 - 900 °C is 80 - 100 °C / min. First, heating is carried out at a slower heating rate and then heat preservation is carried out, which can avoid generating large thermal stresses in the titanium material and the steel material during the heating process. After heat preservation at 300 - 500 °C, heating is carried out at a faster heating rate to 700 - 900 °C, which has the beneficial effect of reducing the time of the metal plate in the high-temperature range, that is, weakening the influence of the reduction in strength of the metal plate due to high temperature.

[0022] Preferably, the heat preservation time at 300 - 500 °C is 20 - 40 min. For example, the heat preservation time at 300 - 500 °C is 25 - 35 min.

[0023] Preferably, during welding, after the AlLiMgSnTi high-entropy alloy melts, the heat preservation temperature is 700 - 900 °C.

[0024] Preferably, during welding, after the AlLiMgSnTi high-entropy alloy melts, the heat preservation time is 20 to 60 minutes. For example, during welding, after the AlLiMgSnTi high-entropy alloy melts, the heat preservation time is 30 to 40 minutes. After the AlLiMgSnTi high-entropy alloy melts, heat preservation for 20 to 60 minutes can enable the composite plate to obtain a good metallurgical bonding effect. Applying pressure during heat preservation and cooling to squeeze the welding parts of the titanium material and the steel material can enable the titanium material and the steel material to better perform metallurgical bonding through the melted AlLiMgSnTi high-entropy alloy, thereby improving the bonding strength between the titanium material and the steel material.

[0025] Preferably, during welding, the cooling method includes the following steps: First, cool at a cooling rate of 20 to 100 °C / h to 100 to 200 °C, and then air-cool. When cooling, using a slower cooling rate first can avoid generating large thermal stresses, thereby reducing the damage caused by thermal stresses to the metallurgical bonding between the titanium material and the steel material.

[0026] The technical solution adopted for the titanium-steel bimetallic composite plate of the present invention is as follows:

[0027] A titanium-steel bimetallic composite plate is obtained by compounding a titanium plate and a steel plate with an AlLiMgSnTi high-entropy alloy as an intermediate alloy.

[0028] The titanium-steel bimetallic composite plate of the present invention uses an AlLiMgSnTi high-entropy alloy as an intermediate alloy. Since the high-entropy alloy does not contain iron elements, the high-entropy alloy can reduce the mutual diffusion between titanium and iron and can effectively inhibit the diffusion of carbon elements in the steel into the titanium alloy layer to generate intermetallic compounds, thereby reducing the formation of brittle phases, and further improving the bonding strength, shear strength, and corrosion resistance of the titanium-steel bimetallic composite plate.

[0029] Preferably, in the titanium-steel bimetallic composite plate, the AlLiMgSnTi high-entropy alloy is composed of the following elements in mole percentages: Al: 18 - 30%, Li: 11 - 25%, Mg: 5 - 15%, Sn: 10 - 18%, and Ti: 30 - 38%. For example, in the titanium-steel bimetallic composite plate, the AlLiMgSnTi high-entropy alloy is composed of the following elements in mole percentages: Al: 25%, Li: 15%, Mg: 10%, Sn: 15%, and Ti: 35%.

[0030] The present invention places no restrictions on the titanium plate, and any titanium plate used for the titanium-steel bimetallic composite plate can be used in the present invention. For example, the titanium plate is pure titanium or a titanium alloy.

[0031] Preferably, the titanium plate is composed of the following elements by mass percentage: Al: 5.50% - 6.75%, V: 3.50% - 4.50%, Fe: ≤0.30%, C: ≤0.10%, N: ≤0.05%, H: ≤0.015%, O: ≤0.20%, and the balance is Ti.

[0032] Preferably, the titanium plate is TC4.

[0033] The present invention has no restrictions on the steel plate, and any steel plate used for the titanium-steel bimetallic composite plate can be used in the present invention. For example, the steel plate is ordinary steel or stainless steel. For example, the steel plate is ordinary steel, and the ordinary steel is Q356, 45# steel or 40Cr steel. The steel plate is stainless steel, and the stainless steel is martensitic stainless steel or austenitic stainless steel. Further, the steel plate is martensitic stainless steel, and the martensitic stainless steel is 2Cr13. Further, the steel plate is austenitic stainless steel, and the austenitic stainless steel is 1Cr18Ni9 or 316L.

[0034] The technical solution adopted by the preparation method of the titanium-steel bimetallic composite plate of the present invention is as follows:

[0035] A preparation method of the above-mentioned titanium-steel bimetallic composite plate, comprising the following steps: heating the slab to melt the AlLiMgSnTi high-entropy alloy powder, cooling after heat preservation, and then obtaining; applying pressure during heat preservation and cooling to squeeze the titanium plate and the steel plate against each other; the slab includes a steel plate, a titanium plate, and a high-entropy alloy powder layer provided between the steel plate and the titanium plate.

[0036] The preparation method of the titanium-steel bimetallic composite plate of the present invention has a simple process, and the prepared titanium-steel composite material has good corrosion resistance.

[0037] Preferably, in the preparation method of the titanium-steel bimetallic composite plate, the pressure is 300 - 780 Pa. For example, in the preparation method of the titanium-steel bimetallic composite plate, the pressure is 333 - 778 Pa.

[0038] Preferably, in the preparation method of the titanium-steel bimetallic composite plate, after the AlLiMgSnTi high-entropy alloy powder is melted, the heat preservation temperature is 700 - 900 °C.

[0039] Preferably, in the preparation method of the titanium-steel bimetallic composite plate, after the AlLiMgSnTi high-entropy alloy powder is melted, the heat preservation time is 20 - 60 min. For example, in the preparation method of the titanium-steel bimetallic composite plate, after the AlLiMgSnTi high-entropy alloy powder is melted, the heat preservation time is 30 - 40 min.

[0040] Preferably, in the method for preparing the titanium-steel bimetal composite plate, the AlLiMgSnTi high-entropy alloy powder is composed of the following elements in molar percentages: Al: 18 - 30%, Li: 11 - 25%, Mg: 5 - 15%, Sn: 10 - 18%, and Ti: 30 - 38%. For example, in the method for preparing the titanium-steel bimetal composite plate, the AlLiMgSnTi high-entropy alloy is composed of the following elements in molar percentages: Al: 25%, Li: 15%, Mg: 10%, Sn: 15%, and Ti: 35%.

[0041] Preferably, in the method for preparing the titanium-steel bimetal composite plate, the method for heating to melt the AlLiMgSnTi high-entropy alloy powder includes the following steps: First, heat the slab to 300 - 500 °C for heat preservation, and then heat it to 700 - 900 °C to melt the AlLiMgSnTi high-entropy alloy powder. Preferably, in the method for preparing the titanium-steel bimetal composite plate, the heat preservation time at 300 - 500 °C is 20 - 40 min. For example, in the method for preparing the titanium-steel bimetal composite plate, the heat preservation time at 300 - 500 °C is 25 - 35 min.

[0042] Preferably, in the method for preparing the titanium-steel bimetal composite plate, in the method for heating to melt the AlLiMgSnTi high-entropy alloy powder, the heating rate from 300 - 500 °C is 25 - 70 °C / min.

[0043] Preferably, in the method for preparing the titanium-steel bimetal composite plate, in the method for heating to melt the AlLiMgSnTi high-entropy alloy powder, the heating rate from 300 - 500 °C to 700 - 900 °C is 70 - 130 °C / min. For example, in the method for preparing the titanium-steel bimetal composite plate, in the method for heating to melt the AlLiMgSnTi high-entropy alloy powder, the heating rate from 300 - 500 °C to 700 - 900 °C is 80 - 100 °C / min.

[0044] In order to reduce the thermal stress, a lower cooling rate can be adopted. Preferably, in the method for preparing the titanium-steel bimetal composite plate, the cooling method includes the following steps: First, cool at a cooling rate of 20 - 100 °C / h to 100 - 200 °C, and then air-cool.

[0045] Preferably, in the method for preparing the titanium-steel bimetal composite plate, the thickness of the high-entropy alloy powder layer is 300 - 1500 μm. For example, in the method for preparing the titanium-steel bimetal composite plate, the thickness of the high-entropy alloy powder layer is 500 - 1500 μm. Description of the Drawings

[0046] Figure 1Schematic diagram of the positions of the steel plate, titanium plate and high-entropy alloy powder during the preparation of the titanium-steel bimetal composite plate in Example 7; the reference signs are as follows: 1 - steel plate, 2 - titanium plate, 3 - high-entropy alloy powder layer;

[0047] Figure 2 Schematic diagram of the test method for the interfacial bonding strength in the experimental example; the reference signs are as follows: 4 - titanium plate of the titanium-steel bimetal composite plate, 5 - indenter, 6 - steel frame, 7 - WDW-300 microcomputer-controlled electronic universal material testing machine, 8 - steel plate of the titanium-steel bimetal composite plate. Detailed implementation manners

[0048] The technical solutions of the present invention will be further described below in conjunction with specific embodiments.

[0049] I. Specific embodiments of the application of the AlLiMgSnTi high-entropy alloy of the present invention as a filler metal in the welding of titanium and steel are as follows:

[0050] Example 1

[0051] The specific method for the application of the AlLiMgSnTi high-entropy alloy of this example as a filler metal in the welding of titanium and steel is as shown in Example 7, and will not be elaborated here.

[0052] Example 2

[0053] The specific method for the application of the AlLiMgSnTi high-entropy alloy of this example as a filler metal in the welding of titanium and steel is as shown in Example 8, and will not be elaborated here.

[0054] Example 3

[0055] The specific method for the application of the AlLiMgSnTi high-entropy alloy of this example as a filler metal in the welding of titanium and steel is as shown in Example 9, and will not be elaborated here.

[0056] II. Specific embodiments of the titanium-steel bimetal composite plate of the present invention are as follows:

[0057] Example 4

[0058] The titanium-steel bimetal composite plate of this example is obtained by using the AlLiMgSnTi high-entropy alloy as an intermediate alloy to composite the titanium plate and the steel plate. Among them, the AlLiMgSnTi high-entropy alloy is composed of the following elements in mole percentages: Al: 25%, Li: 15%, Mg: 10%, Sn: 15%, and Ti: 35%. The steel plate is a martensitic stainless steel (2Cr13) plate, and the titanium plate is a titanium alloy (TC4) plate.

[0059] Example 5

[0060] The titanium-steel bimetallic composite plate of this embodiment is obtained by using an AlLiMgSnTi high-entropy alloy as an intermediate alloy to composite a titanium plate and a steel plate. Among them, the AlLiMgSnTi high-entropy alloy is composed of the following elements in molar percentages: Al: 18%, Li: 11%, Mg: 15%, Sn: 18%, and Ti: 38%. The steel plate is an austenitic stainless steel (316L) plate, and the titanium plate is a titanium alloy (TC4) plate.

[0061] Example 6

[0062] The titanium-steel bimetallic composite plate of this embodiment is obtained by using an AlLiMgSnTi high-entropy alloy as an intermediate alloy to composite a titanium plate and a steel plate. Among them, the AlLiMgSnTi high-entropy alloy is composed of the following elements in molar percentages: Al: 30%, Li: 25%, Mg: 5%, Sn: 10%, and Ti: 30%. The steel plate is a Q356 steel plate, and the titanium plate is a titanium alloy (TC4) plate.

[0063] III. Specific embodiments of the preparation method of the titanium-steel bimetallic composite plate of the present invention are as follows:

[0064] Example 7

[0065] The preparation method of the titanium-steel bimetallic composite plate of this embodiment is the same as that of the titanium-steel bimetallic composite plate in Example 4, including the following steps:

[0066] (1) Perform machining treatment on the surfaces of the steel plate and the titanium plate to be composite, so that the surfaces of the steel plate and the titanium plate to be composite expose fresh metal; the sizes of the steel plate and the titanium alloy plate are both 300×300 mm, and the thickness is 10 mm;

[0067] (2) Using the steel plate as the bottom plate, evenly lay a layer of AlLiMgSnTi high-entropy alloy powder with a thickness of 500 μm on the surface of the steel plate to be composite, and then place the titanium plate on the surface of the AlLiMgSnTi high-entropy alloy powder with the surface to be composite facing the AlLiMgSnTi high-entropy alloy powder to obtain a slab (the slab is as shown in Figure 1 including a steel plate 1, a titanium plate 2, and a high-entropy alloy powder layer 3), then heat it to 300 °C at a heating rate of 25 °C / min, hold for 20 min, and then heat it to 700 °C at a heating rate of 70 °C / min to melt the AlLiMgSnTi high-entropy alloy powder, then hold at 700 °C for 20 min and use a fixture to clamp the slab to make the steel plate and the titanium plate extrude each other. The pressure applied by the fixture is 30 N. Finally, cool it to 100 °C at a cooling rate of 20 °C / h, and then air-cool to obtain the titanium-steel bimetallic composite plate.

[0068] In this embodiment, the steel plate is a martensitic stainless steel (2Cr13) plate, the titanium plate is a titanium alloy (TC4) plate, and the AlLiMgSnTi high-entropy alloy powder is composed of the following elements in molar percentages: Al: 25%, Li: 15%, Mg: 10%, Sn: 15%, and Ti: 35%.

[0069] Example 8

[0070] The preparation method of the titanium-steel bimetallic composite plate in this embodiment is the same as that of the titanium-steel bimetallic composite plate in Example 5, including the following steps:

[0071] (1) Machining the surfaces to be compounded of the steel plate and the titanium plate to expose fresh metal on the surfaces to be compounded of the steel plate and the titanium plate; the sizes of the steel plate and the titanium alloy plate are both 300×300 mm, and the thickness is 10 mm;

[0072] (2) Using the steel plate as the bottom plate, evenly laying a layer of AlLiMgSnTi high-entropy alloy powder with a thickness of 750 μm on the surface to be compounded of the steel plate, then placing the titanium plate on the surface of the AlLiMgSnTi high-entropy alloy powder with the surface to be compounded facing the AlLiMgSnTi high-entropy alloy powder, then heating at a heating rate of 60 °C / min to 400 °C, holding for 30 min, then heating at a heating rate of 90 °C / min to 800 °C to melt the AlLiMgSnTi high-entropy alloy powder, then holding at 800 °C for 40 min and fixing the steel plate and the titanium plate with a fixture to make the steel plate and the titanium plate extrude each other, the pressure applied by the fixture is 50 N, and finally cooling at a cooling rate of 60 °C / h to 150 °C, and then air-cooling to obtain the titanium-steel bimetallic composite plate.

[0073] In this embodiment, the steel plate is an austenitic stainless steel (316L) plate, the titanium plate is a titanium alloy (TC4) plate, and the AlLiMgSnTi high-entropy alloy powder is composed of the following elements in molar percentages: Al: 18%, Li: 11%, Mg: 15%, Sn: 18%, and Ti: 38%.

[0074] Example 9

[0075] The preparation method of the titanium-steel bimetallic composite plate in this embodiment is the same as that of the titanium-steel bimetallic composite plate in Example 6, including the following steps:

[0076] (1) Machining the surfaces to be compounded of the steel plate and the titanium plate to expose fresh metal on the surfaces to be compounded of the steel plate and the titanium plate; the sizes of the steel plate and the titanium alloy plate are both 300×300 mm, and the thickness is 10 mm;

[0077] (2) Using a steel plate as the bottom plate, a layer of AlLiMgSnTi high-entropy alloy powder with a thickness of 1500 μm is evenly laid on the surface of the steel plate to be compounded. Then, the titanium plate is placed on the surface of the AlLiMgSnTi high-entropy alloy powder with the surface to be compounded facing the AlLiMgSnTi high-entropy alloy powder. Then, it is heated to 500 °C at a heating rate of 70 °C / min, held for 40 min, and then heated to 900 °C at a heating rate of 130 °C / min to melt the AlLiMgSnTi high-entropy alloy powder. Then, it is held at 900 °C for 60 min, and the steel plate and the titanium plate are fixed with a fixture to make the steel plate and the titanium plate squeeze each other. The pressure applied by the fixture is 70 N. Finally, it is cooled to 200 °C at a cooling rate of 100 °C / h, and then air-cooled to obtain a titanium-steel bimetal composite plate.

[0078] In this embodiment, the steel plate is a Q356 steel plate, the titanium plate is a titanium alloy (TC4) plate, and the AlLiMgSnTi high-entropy alloy powder is composed of the following elements in molar percentages: Al: 30%, Li: 25%, Mg: 5%, Sn: 10%, and Ti: 30%.

[0079] Experimental example

[0080] The interfacial bonding strength and corrosion resistance of the titanium-steel bimetal composite plates prepared in Examples 7-9 were tested respectively.

[0081] Among them, the test method for the interfacial bonding strength is as follows: The titanium-steel bimetal composite plate is fixed on a WDW-300 microcomputer-controlled electronic universal material testing machine 7 with a steel frame 6, as Figure 2 shown, and the steel plate 8 side of the titanium-steel bimetal composite plate is on the outside and the titanium plate 4 side is on the inside. Then, the indenter 5 is brought into contact with the steel plate 8 in the titanium-steel bimetal composite plate, and then loaded continuously from top to bottom at a loading speed of 0.5 mm / min to cause the titanium-steel bimetal composite plate to fracture along the titanium-steel bonding interface; during the experiment, the maximum load applied is recorded, and the measured interfacial bonding strength is equal to the ratio of the maximum load to the area of the titanium-steel bonding interface; three samples are selected from the titanium-steel bimetal composite plates prepared in the same embodiment, and the average value of the interfacial bonding strengths of the three samples is used as the final interfacial bonding strength.

[0082] The test method for corrosion resistance is as follows: The titanium-steel bimetallic composite plates prepared in Examples 7-9 are subjected to neutral salt spray (NSS) experiments in accordance with the provisions of the standard GB-T 10125-2012 "Artificial Atmosphere Corrosion Test - Salt Spray Test". During the experiment, the concentration of the sodium chloride solution used is 50 g / L, the pH is 7, the temperature is 35 °C, the experimental period is 1000 h, and the spray pressure is 84 kPa. After the experiment, the titanium-steel bimetallic composite plates are simply cleaned with distilled water, then dried, and then the protective rating (R P ) and appearance rating (R A ) of the corroded surface of the titanium plate in the dried titanium-steel bimetallic composite plates are evaluated in accordance with the provisions of the standard GB-T 6461-2002 "Rating of Specimens and Test Pieces of Metallic and Other Inorganic Coatings on Metallic Substrates After Corrosion Tests".

[0083] The test results of the interfacial bonding strength and corrosion resistance of the titanium-steel bimetallic composite plates prepared in Examples 7-9 are shown in Table 1. At the same time, the corrosion resistance of the titanium alloy (TC4) plate is tested in accordance with the above-mentioned test method for corrosion resistance, and the protective rating (R P ) and appearance rating (R A ) of the corroded surface of the titanium plate are evaluated. The results show that the protective rating (R P ) and appearance rating (R A ) of the pure titanium alloy (TC4) plate are 9 and 9 respectively.

[0084] Table 1 Interfacial bonding strength and corrosion resistance of the titanium-steel bimetallic composite plates prepared in Examples 7-9

[0085]

[0086]

[0087] As can be seen from Table 1, the interfacial bonding strength of the titanium-steel bimetallic composite plates in the examples can reach above 260 MPa, and the corrosion resistance reaches level 9, which can meet the requirements of high-strength and corrosion-resistant structural parts in the marine environment.

Claims

1. Application of an AlLiMgSnTi high-entropy alloy as a filler metal in welding titanium materials and steel materials, characterized in that, The AlLiMgSnTi high-entropy alloy consists of elements in the following molar percentages : Al: 18 - 30%, Li: 11 - 25%, Mg: 5 - 15%, Sn: 10 - 18%, and Ti: 30 - 38%.

2. The application according to claim 1, characterized in that The titanium material consists of elements in the following mass percentages : Al: 5.50% - 6.75%, V: 3.50% - 4.50%, Fe: ≤0.30%, C: ≤0.10%, N: ≤0.05%, H: ≤0.015%, O: ≤0.20%, with the balance being Ti.

3. The application according to claim 1 or 2, characterized in that, The welding is carried out by placing the AlLiMgSnTi high-entropy alloy between the parts to be welded of the titanium material and the steel material, heating to melt the AlLiMgSnTi high-entropy alloy, then keeping warm and cooling, and applying pressure during the heat preservation and cooling processes to make the welded parts of the titanium material and the steel material squeeze against each other.

4. A titanium-steel bimetallic composite plate, characterized in that, It is obtained by compounding a titanium plate and a steel plate with the AlLiMgSnTi high-entropy alloy as an intermediate alloy; the AlLiMgSnTi high-entropy alloy consists of elements in the following molar percentages : Al: 18 - 30%, Li: 11 - 25%, Mg: 5 - 15%, Sn: 10 - 18%, and Ti: 30 - 38%.

5. The titanium-steel bimetallic composite plate according to claim 4, wherein The titanium plate consists of elements in the following mass percentages : Al: 5.50% - 6.75%, V: 3.50% - 4.50%, Fe: ≤0.30%, C: ≤0.10%, N: ≤0.05%, H: ≤0.015%, O: ≤0.20%, with the balance being Ti.

6. A preparation method of the titanium-steel bimetal composite plate as described in claim 4 or 5, characterized in that, It includes the following steps: heating the slab to melt the AlLiMgSnTi high-entropy alloy powder, keeping warm and then cooling down to obtain it; applying pressure during the heat preservation and cooling processes to make the titanium plate and the steel plate squeeze against each other; the slab includes a steel plate, a titanium plate, and a high-entropy alloy powder layer arranged between the steel plate and the titanium plate; the AlLiMgSnTi high-entropy alloy powder consists of elements in the following molar percentages : Al: 18 - 30%, Li: 11 - 25%, Mg: 5 - 15%, Sn: 10 - 18%, and Ti: 30 - 38%.

7. The manufacturing method of the titanium-steel bimetal composite plate according to claim 6, characterized in that, The method for heating to melt the AlLiMgSnTi high-entropy alloy powder includes the following steps: first heating the slab to 300 - 500 °C for heat preservation, and then heating to 700 - 900 °C to melt the AlLiMgSnTi high-entropy alloy powder.

8. The preparation method of the titanium-steel bimetal composite plate according to claim 6 or 7, characterized in that, The method for cooling down includes the following steps: first cooling at a cooling rate of 20 - 100 °C / h to 100 - 200 °C, and then air cooling.

9. The method for preparing a titanium-steel bimetallic composite plate according to claim 6 or 7, characterized in that, The thickness of the high-entropy alloy powder layer is 300 - 1500 μm; the pressure is 300 - 780 Pa.

Images