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CN-115635154-B - Method for connecting carbon materials by adopting high-entropy alloy solder

CN115635154BCN 115635154 BCN115635154 BCN 115635154BCN-115635154-B

Abstract

The invention provides a method for connecting carbon materials by adopting high-entropy alloy solder, which solves the technical problem that the structure obtained by the existing connecting method can not meet the ultra-high temperature service requirement. The invention is based on IVB-VIB refractory high-entropy alloy, utilizes the advantages of high-entropy effect and high heating speed of discharge plasma connection process, can promote element diffusion in the joint, controllable tissue structure and the like, generates high-entropy carbide in the joint tissue through carbonization reaction of the high-entropy alloy to realize regulation and control of good high-temperature mechanical property and high-temperature stability of the high-temperature carbon material joint, and reduces joint residual stress through residual high-entropy alloy layer, thereby improving joint toughness and joint strength at room temperature, and finally obtaining the carbon material connection joint with good comprehensive performance under high-temperature service condition.

Inventors

  • FU LI
  • WANG XINCHENG
  • MAO YUE
  • XIAO XUAN
  • QIN DINGQIANG

Assignees

  • 西北工业大学

Dates

Publication Date
20260512
Application Date
20221020

Claims (8)

  1. 1. A method for connecting carbon materials by adopting high-entropy alloy solder is characterized in that the high-entropy alloy solder comprises TiZrHfTa percent of components in a molar percentage range of 15-35 percent; The method specifically comprises the following steps: 1) Preparing high-entropy alloy solder foil Weighing the required pure metal according to the high-entropy alloy proportion, and preparing a high-entropy alloy solder foil with the thickness of 150-200 mu m; 2) Carbon material joining 2.1 Placing the high-entropy alloy solder foil prepared in the step 1) between the surfaces to be welded of the two pretreated carbon material blocks to be welded to form a welding assembly body with a sandwich structure; 2.2 Placing the welding assembly prepared in the step 2.1) in a discharge plasma sintering furnace, and applying pressure to the welding assembly to ensure that all surfaces to be welded are fully contacted; 2.3 Heat treatment is carried out on a sample to be welded, and the following two modes are adopted: First kind: The discharge plasma sintering furnace is operated at full power, and is heated for 14-18 seconds, the temperature is heated to 2000-2300 ℃ within the heating time range, after the heating is finished, the furnace is cooled to below 50 ℃ within 3 minutes, and the cooling rate is more than 500 ℃ per minute, so that the connection is completed; Second kind: Heating a sample to be welded to 1200-1400 ℃ at a temperature rising rate of 20-60 ℃ per minute, heating the sample to 1800-2200 ℃ at a rate of 20-40 ℃ per minute, preserving heat for 10-60 minutes at a target temperature, and then cooling to room temperature at a rate of 50-100 ℃ per minute to finish connection; The obtained sample can be used in an ultra-high temperature service environment with the temperature of above 1600 ℃ and has the shearing strength of up to 27.3 MPa at the temperature of 1600 ℃.
  2. 2. The method according to claim 1, wherein step 1) is specifically: 1.1 Weighing the required pure metal according to the high-entropy alloy ratio; 1.2 Mixing the weighed pure metals, and adopting electric arc melting or electromagnetic melting for a plurality of times under vacuum or inert atmosphere to prepare a high-entropy alloy cast ingot; 1.3 After the high-entropy alloy cast ingot is cooled to room temperature, taking out, rolling into a foil with the thickness of 300-500 mu m; 1.4 Polishing, polishing and ultrasonic cleaning the foil in sequence to obtain the high-entropy alloy solder foil with the thickness of 150-200 mu m.
  3. 3. The method according to claim 2, characterized in that: In the step 2.1), the pretreatment refers to sequentially polishing and polishing the surface to be welded of the carbon material block to be welded and ultrasonically cleaning the surface to be welded; In the step 2.2), a pressure of 10-20 MPa is applied to the welding assembly, and a vacuum or inert atmosphere with the pressure of less than 1X 10 -3 Pa is arranged in the discharge plasma sintering furnace.
  4. 4. A method according to claim 3, characterized in that: in step 2.3), in a first mode, the rate of temperature increase is greater than 100 ℃ per second.
  5. 5. The method according to claim 4, wherein: the carbon material is single-phase carbon or carbon-based composite material.
  6. 6. A carbon material joint is characterized in that the joint is prepared by adopting the method of any one of claims 1-5, and the microstructure of a joint reaction layer is single high-entropy carbide ceramic or a structure of a high-entropy carbide and high-entropy alloy layer.
  7. 7. The carbon material joint as set forth in claim 6, wherein the carbon material joint is capable of being used in an ultra-high temperature service environment at a temperature of 1600 ℃ or higher.
  8. 8. The carbon material joint of claim 7, wherein the joint has a shear strength of up to 27.3 MPa at 1600 ℃.

Description

Method for connecting carbon materials by adopting high-entropy alloy solder Technical Field The invention belongs to the technical field of materials, and particularly relates to a method for connecting carbon materials by adopting novel high-entropy alloy solder. Background Carbon-based materials such as graphite and C/C composite materials can be applied to a series of high-temperature extreme environments such as aerospace, nuclear industry and the like due to the special heat resistance and electric/thermal properties. For example, the C/C composite material has the characteristics of light specific gravity, low linear expansion coefficient, strong heat and electricity conducting capability, excellent thermal shock resistance, friction and abrasion resistance and the like, and is widely applied to manufacturing of aerospace structural members in recent years. However, the C/C composite material is limited by a preparation process, and the direct preparation of a large-scale composite structure still has great difficulty and high cost, so that engineering application of the high-temperature carbon material is urgently needed to prepare a high-temperature-resistant high-strength and high-toughness connecting joint. Brazing is the main connecting method of the high-temperature carbon material at present, and the traditional brazing filler metal mainly based on Cu base, ti base and Ag base is adopted in most cases. If He selects Ti 14Si86 eutectic alloy, the braze welding connection of the C/C composite material is successfully realized by adopting a pre-infiltration method, the obtained joint has the highest shearing strength of 26 MPa at room temperature, the theoretical service temperature is about 1000 ℃ and the service cannot be carried out under the ultra-high temperature environment (Z. J. He, C. Li , J. L. Qi, et al. Pre-infiltration and Brazing Behaviors of Cf/C Composites with High Temperature Ti-Si Eutectic Alloy. Carbon, 2018, 140:57-67.). Chinese patent application CN 114346346A, which provides a method for connecting high-entropy carbide ceramics by high-entropy alloy brazing, discloses a method for connecting (HfZrTiTaNb) C high-entropy carbide ceramics by FeCoCrNiTix high-entropy alloy brazing filler metal. Although the high-entropy alloy brazing filler metal in the method can avoid generating intermetallic compounds in the brazing joint, the reaction between the alloy brazing filler metal and the carbide ceramic base metal can lead to serious component segregation on one side of the base metal, and the residual of a large amount of low-melting-point alloy layers in the joint structure enables the service temperature of the joint to be only 800 ℃, so that the brazing joint obtained at a lower process temperature is obviously not suitable for high-temperature carbon in service in an ultra-high temperature environment. Therefore, no proper brazing filler metal system and brazing technology for the ultra-high temperature service environment exist at present for the high temperature carbon material. In view of this, it is necessary to continue to explore a method for solving the problem of connecting the current high temperature resistant carbon material and its large structure. Disclosure of Invention The invention aims to solve the technical problem that the structure obtained by the existing connection method cannot meet the ultra-high temperature service requirement, and provides a method for connecting carbon materials by adopting novel high-entropy alloy front solder. The conception of the invention: Compared with the traditional alloy solder, the high-entropy alloy has the characteristics of high strength, high plasticity, high fracture toughness and the like, and the refractory high-entropy alloy formed by elements of IVB-VIB groups has excellent high-temperature performance and good structural stability, however, the development of the refractory high-entropy alloy as the solder is limited due to the characteristics of high melting point (usually higher than 1800 ℃), difficult diffusion of the elements and the like. With the continuous and deep research of high-entropy alloy, the research of high-entropy carbide ceramics is developed, and the research is mainly focused on solid solutions of transition metal IVB and VB carbide. These carbides have strong covalent bond characteristics and high melting points and can be applied to various extreme conditions. From the ultra-high temperature service environment of the high-temperature carbon material, if refractory high-entropy alloy brazing filler metal required by the preparation of the high-temperature and high-strength carbon material connecting structure can be prepared, the refractory high-entropy alloy brazing filler metal has very important significance for the high-temperature carbon material, and therefore, the research team of the invention aims to search for suitable refractory high-entropy alloy in elements from IVB to VIB as b