Corundum mullite ceramic material, titanium alloy composite material and manufacturing method and application of corundum mullite ceramic material and titanium alloy composite material
By controlling apparent porosity and sintering parameters, a high-purity corundum mullite ceramic and TC4 titanium alloy composite material was prepared, solving the problems of flammability, heavy weight and low thermal conductivity of existing materials under high temperature conditions, and achieving improved performance of the flame tube with high temperature stability and lightweight.
Patent Information
- Application Number
- CN202411578823.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-06
- Publication Date
- 2025-11-21
AI Technical Summary
When existing titanium alloys and ceramic matrix composites are used in the combustion chamber flame tubes of aero engines, they suffer from problems such as flammability, low thermal conductivity, large weight, complex manufacturing process and many internal defects, making it difficult to meet the requirements of stability and lightweight in high-temperature environments.
Using high-purity corundum and mullite as the main crystalline phases, a corundum-mullite ceramic material with a bending strength ≥550MPa is prepared by controlling the apparent porosity at 28-35%, the sintering temperature at 1800-1850℃ and the sintering time at 3-3.5h, and adding ATM additive. This material is then brazed with a TC4 titanium alloy layer to form a cylindrical structure, thus creating a composite material.
It improves the high-temperature strength and thermal stability of the material, reduces weight, enhances thermal conductivity, overcomes the flammability of titanium alloy, has a wider range of applications, significantly improves the performance of the flame tube, and conforms to the trend of lightweight aero-engines.
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Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to brazing technology, in particular to a corundum mullite ceramic material, a titanium alloy composite material and a manufacturing method and application thereof. BACKGROUND
[0002] The working temperature of the combustion chamber flame tube of an aero-engine is very high, generally above 500℃, and the temperature of local areas can even reach above 1000℃ under the maximum working condition. The combustion chamber flame tube is an important component in the combustion chamber, and its working conditions are very severe, needing to withstand high temperature, high load and high-speed airflow impact. The material of the flame tube has a crucial influence on the performance and reliability of the engine.
[0003] The flame tube is usually made of materials that are resistant to high temperature, corrosion, oxidation and fatigue, and the materials mainly include titanium alloy, high-temperature alloy and ceramic composite material, etc. These materials can ensure that the flame tube remains stable under extreme working conditions and has a long service life. Among them, the advantages of titanium alloy lie in its high strength, corrosion resistance and heat resistance, which can withstand the combined action of high temperature and high load; and the processing performance of titanium alloy is good, and it is easy to be welded and processed into a shape. Ceramic matrix composite material has excellent high-temperature resistance, oxidation resistance and corrosion resistance, and can remain stable under extreme conditions; and it has high thermal conductivity, which is beneficial to heat dissipation, and can withstand the impact of high-speed airflow. In addition, ceramic matrix composite material also has the advantages of light weight, high hardness and fatigue resistance, etc.
[0004] However, the existing titanium alloy as the material of the combustion chamber flame tube of an aero-engine still has the disadvantages of flammability, low thermal conductivity, limited application range and heavy weight, etc. The existing ceramic matrix composite material also has the disadvantages of complex preparation process, and not only volume and area defects such as holes, inclusions, cracks, delamination and uneven density are easy to appear in the internal and interface phase, but also use damage is easy to occur. These defects and damage have the characteristics of micro-to-millimeter scale, complex defect / damage and size atlas, and once the material defects and use damage are not detected in time, it may cause a catastrophic accident, bringing great difficulty to the quality control of ceramic matrix composite material.
[0005] Common corundum mullite ceramic is a ceramic material mainly composed of corundum and mullite. It has high mechanical strength, good insulation performance and stable dielectric performance. Its relative dielectric constant is usually between 6 and 7, the dielectric loss tangent value is low, and the volume resistivity is high. This ceramic material has strong chemical corrosion resistance, good thermal stability, and can withstand rapid cooling and heating without peeling. In addition, the corundum mullite ceramic has good thermal shock resistance and can be fired at high temperature in an oxidizing atmosphere. It is widely used to manufacture various types of high-voltage insulators, bushings, high-voltage switches and other device parts. Through research, the existing corundum mullite ceramic is not suitable for manufacturing rocket engine combustion cylinder parts due to low strength and poor heat dissipation performance, and is only suitable for high-temperature tunnel kiln insulation bricks and roller kiln and push plate kiln lining bricks. SUMMARY
[0006] Corundum mullite ceramic material is a porous material, and its mechanical and thermal properties are closely related to the apparent porosity. If the apparent porosity is too high, the mechanical properties such as strength and toughness of the ceramic will be reduced, because the existence of pores reduces the bearing area of the material and to some extent causes stress concentration; and the high apparent porosity will also result in low thermal conductivity, which is mainly because the existence of pores makes heat transfer easier, and gas is a poor conductor of heat. High apparent porosity may reduce its heat dissipation performance at cold state, although it has good heat preservation performance at high temperature; in addition, it can also achieve the purpose of weight reduction. If the apparent porosity is too low, the density of corundum mullite ceramic will increase, the mechanical properties such as strength and toughness will increase, and the heat dissipation performance will also be enhanced, but the heat preservation performance at high temperature will decrease, and the purpose of weight reduction cannot be achieved, which cannot meet the development trend of lightweight of future aero-engine. Therefore, when applying corundum mullite ceramic material to manufacture rocket engine combustion cylinder parts, the apparent porosity needs to be controlled, so that it can have good mechanical and thermal properties while achieving the purpose of weight reduction.
[0007] Therefore, the main purpose of the present application is to provide a corundum mullite ceramic material with high strength, good thermal performance, and suitable for high temperature environment, which can be used for rocket cylinder materials.
[0008] To this end, the present application provides a corundum mullite ceramic material, which is mainly composed of corundum and mullite, composed of corundum micro powder and mullite particles, and sintered at high temperature, and the bending strength of the corundum mullite ceramic is ≥550MPa, the apparent porosity is ≤35%, the bulk density is 1.55-1.65g / cm 3The chemical formula of mullite in the present application is 3Al2O3·2SiO2, the main component of corundum is α-Al2O3, and the purity of mullite and corundum is ≥ 99.5%. The performance parameters of the material in the present application, which are not particularly mentioned, are the bending strength, apparent porosity, bulk density, fracture toughness and other performance parameters measured at room temperature. The "room temperature" refers to 20-30℃.
[0009] In order to ensure that the above-mentioned corundum-mullite ceramic material has good mechanical properties such as strength, toughness, impact resistance and good thermal properties, the mass ratio of mullite particles to corundum micropowder is preferably 55-65:35-45. The sintering temperature and sintering time mainly affect the bonding strength of corundum micropowder and mullite particles in the corundum-mullite ceramic, and then affect the bending strength of the ceramic, therefore, the sintering temperature is preferably 1800℃-1850℃, and the sintering time is preferably 3-3.5h.
[0010] In the high-temperature sintering process, ATM additive is also added to improve the thermal shock resistance and high-temperature bending strength of the corundum-mullite ceramic. Preferably, the amount of ATM additive added is 0.3-0.5% of the total mass of the corundum-mullite ceramic material. The ATM additive is an aluminum titanate-mullite composite material, and the mass ratio of aluminum titanate to mullite therein is 6:4-7:3.
[0011] The apparent porosity is directly related to the particle size of corundum micropowder and mullite. In order to further improve the mechanical properties and thermal properties of the corundum-mullite ceramic material, so that it can be used to make a flame tube, and also to achieve the purpose of weight reduction of the flame tube, the particle size of the mullite is preferably 72-100 mesh, the particle size of the corundum micropowder is preferably 200-240 mesh, and the apparent porosity is preferably 28-35%.
[0012] The apparent porosity of the corundum-mullite ceramic material is closely related to its bending strength, and both satisfy the following formula:
[0013] R = 120 + 472 / (1 + exp((x-0.4) / dx))
[0014] The second object of the present application is to provide a corundum-mullite ceramic-titanium alloy composite material, which has good mechanical strength, thermal shock resistance and high temperature resistance, and exhibits good creep performance and high temperature stability at high temperature, can withstand large thermal stress and strain, and is not prone to brittle fracture and deformation. The composite material can overcome the use defects of titanium alloy as a flame tube manufacturing material, such as reduction of strength at high temperature, and significantly improve the performance of the flame tube.
[0015] Specifically, the composite material comprises a titanium alloy layer and a corundum mullite ceramic layer brazed on the surface of the titanium alloy layer, and the corundum mullite ceramic layer is composed of the corundum mullite ceramic material. Preferably, the titanium alloy layer and the corundum mullite ceramic layer are both in a cylindrical structure; more preferably, the corundum mullite ceramic layer is welded in the inner layer of the titanium alloy layer.
[0016] A third object of the present application is to provide an application of the above-mentioned corundum mullite ceramic-titanium alloy composite material in manufacturing a rocket engine combustion cylinder, in particular, a flame cylinder. In this way, the use defect of reduced strength at high temperature when titanium alloy is used as a material for manufacturing a flame cylinder can be overcome, the performance of the flame cylinder can be significantly improved, and the weight of the engine flame cylinder can be effectively reduced.
[0017] A fourth object of the present application is to provide a manufacturing method of the above-mentioned corundum mullite ceramic-titanium alloy composite material, so as to obtain a corundum mullite ceramic-titanium alloy brazing composite structure with high connection strength and stable reliability. Specifically, the manufacturing method comprises the step of: welding the corundum mullite ceramic layer and the titanium alloy layer together by using a brazing material and a brazing process, so as to obtain the corundum mullite ceramic-titanium alloy composite material. BRIEF DESCRIPTION OF DRAWINGS
[0018] Figure 1 is a micrograph of the corundum mullite ceramic material provided by the embodiment of the present application, wherein Fig. a is an SEM test diagram of the microstructure of the corundum mullite ceramic, Fig. b is an O element distribution diagram of the corundum mullite ceramic, Fig. c is an Al element distribution diagram of the corundum mullite ceramic, and Fig. d is an Si element distribution diagram of the corundum mullite ceramic;
[0019] Figure 2 is a diagram of the relationship between the apparent porosity and the bending strength of the corundum mullite ceramic material provided by the embodiment of the present application;
[0020] Figure 3 is a microstructure diagram of the weld diffusion zone of the corundum mullite ceramic-titanium alloy composite material S2 after air quenching provided by the embodiment of the present application;
[0021] Figure 4 is a microstructure diagram of the weld diffusion zone of the common corundum mullite ceramic-titanium alloy composite material D1 after air quenching provided by the comparative example. DETAILED DESCRIPTION
[0022] The technical solutions of the present application are described in further detail below through specific embodiments.
[0023] The terms used in the present application are all common terms in the field, and the raw materials, equipment, preparation processes, and test methods used are all prior art in the field, which are not specially described. The materials used are all commercially available.
[0024] The main purpose of the present application is to provide a corundum mullite ceramic material with higher strength, good thermal performance, and suitable for high temperature environment, which can be used for rocket barrel material.
[0025] To this end, the present application provides a corundum mullite ceramic material, taking corundum and mullite as main crystal phase, composed of corundum micro powder and mullite, and made by high temperature sintering, and the bending strength of the corundum mullite ceramic is ≥550MPa, the apparent porosity is ≤35%, and the bulk density is 1.55-1.65g / cm 3 . In this application, the chemical formula of mullite is 3Al2O3·2SiO2, the main component of the corundum micro powder is α-Al2O3, and the purity of the mullite and corundum is ≥99.5%. Preferably, the corundum micro powder is imported plate-shaped corundum or high-purity fused corundum, etc.
[0026] In the preparation process of the above corundum mullite ceramic material, the mass ratio of corundum micro powder and mullite, sintering temperature and sintering time have important influence on the mechanical and thermal properties of the corundum mullite ceramic. When the mass ratio of mullite ceramic particles and corundum micro powder is 55-65:35-45, it is located at the eutectic point of SiO2-Al2O3 phase, at this time the thermal shock resistance of the corundum mullite ceramic material is better. When the addition amount of corundum micro powder is too large or too small, the thermal expansion mismatch degree in the corundum mullite ceramic material is low, and the micro cracks are less. Since the micro cracks can absorb the fracture energy of the ceramic, therefore, when the addition amount of corundum micro powder is too large or too small, it is not conducive to improve the thermal shock resistance of the corundum mullite ceramic material. Therefore, through experiments, the mass ratio of the mullite ceramic particles and the corundum micro powder is preferably 55-65:35-45.
[0027] If the sintering temperature is too high and the sintering time is too long, it may cause the ceramic to appear over-sintering phenomenon, such as abnormal grain growth, reduction of porosity, etc., and the mechanical properties of the corundum mullite ceramic, such as strength, fracture toughness, thermal expansion coefficient, etc., are decreased; if the sintering temperature is too low and the sintering time is too short, the ceramic density and bonding strength are insufficient, and the mechanical properties of the corundum mullite ceramic, such as strength, fracture toughness, thermal expansion coefficient, etc., cannot meet the use requirements. Therefore, through experiments, the sintering temperature is preferably 1800℃-1850℃, and the sintering time is preferably 3-3.5h.
[0028] The apparent porosity has a direct relationship with the particle size of corundum micropowder and mullite. If the particle size of corundum micropowder and mullite is too large, the apparent porosity will be larger, so that the mechanical properties such as strength and toughness of the ceramic are reduced, because the existence of pores reduces the bearing area of the material and to some extent leads to stress concentration; and the apparent porosity is too high, which will also lead to lower thermal conductivity; if the particle size of corundum micropowder and mullite is too small, the apparent porosity will be smaller, so that the density of corundum mullite ceramic increases, the mechanical properties such as strength and toughness are improved, and the heat dissipation performance is also enhanced, but the heat preservation performance at high temperature will be reduced, and it is difficult to achieve the purpose of weight reduction. Therefore, in order to further improve the mechanical properties and thermal properties of corundum mullite ceramic material, so that it can be used to make flame tube, and the flame tube can also achieve the purpose of weight reduction, the particle size of mullite is preferably 72-100 mesh, and the particle size of corundum micropowder is preferably 200-240 mesh. The apparent porosity is preferably 28-35%.
[0029] In the high-temperature sintering process, ATM additive also needs to be added to improve the thermal shock resistance and high-temperature bending strength of corundum mullite ceramic, preferably, the amount of ATM additive is 0.3-0.5% of the total weight of the corundum mullite ceramic material. The ATM additive is an aluminum titanate-mullite composite material, which is an inorganic non-metallic material combining the advantages of aluminum titanate and mullite, and the mass ratio of aluminum titanate to mullite is 6:4-7:3.
[0030] The above corundum mullite ceramic material exhibits different mechanical strength due to different apparent porosities, and the relationship between apparent porosity and bending strength is as follows:
[0031] R = 120 + 472 / (1 + exp((x-0.4) / dx))
[0032] Wherein: R is the bending strength at room temperature, MPa; x is the apparent porosity.
[0033] The above corundum mullite ceramic material has high purity of raw materials and low impurity content, so that it has better chemical stability and thermal stability. The crystal phase composition of the above corundum mullite ceramic is more uniform, and the mechanical properties such as strength, toughness, impact resistance and other properties are excellent, the thermal expansion coefficient is small, and the thermal conductivity is high, so it has good thermal performance and is suitable for application in high temperature environment. The bending strength of the above corundum mullite ceramic at 1000℃ can reach 620MPa, and the fracture toughness KIC is 5.9MPa, so that with the increase of temperature, the strength and toughness not only do not decrease but also increase significantly, which is an excellent characteristic of corundum mullite ceramic as a high-temperature material. The thermal shock resistance of corundum mullite ceramic is one of its important physical properties. The above performance makes the above corundum mullite ceramic material have the feasibility of application in the combustion chamber of an aero-engine.
[0034] The second object of the present application is to provide a corundum mullite ceramic-titanium alloy composite material, which has good high-temperature strength and thermal stability, exhibits good creep performance and high-temperature stability at high temperatures, can withstand large thermal stress and strain, and is not prone to brittle fracture and deformation. The composite material can overcome the use defects of titanium alloy as a flame tube manufacturing material, such as reduction of strength at high temperatures, and significantly improve the performance of the flame tube.
[0035] Specifically, the composite material comprises a titanium alloy layer and a corundum mullite ceramic layer brazed on the surface of the titanium alloy layer, and the corundum mullite ceramic layer is composed of the corundum mullite ceramic material.
[0036] When the corundum mullite ceramic-titanium alloy composite material is used to manufacture a flame tube, it is preferably in a cylindrical structure. The titanium alloy layer and the corundum mullite ceramic layer are in a sleeved cylindrical structure, and the corundum mullite ceramic layer is welded as an inner lining on the inner layer of the titanium alloy layer. Preferably, the titanium alloy is TC4 titanium alloy, and the thickness thereof is preferably 1 mm. The thickness of the corundum mullite ceramic-titanium alloy composite material is preferably 2-2.1 mm.
[0037] The corundum mullite ceramic-titanium alloy composite material provided by the present application has the following characteristics:
[0038] (1) High temperature resistance, not flammable, wide application range
[0039] The corundum mullite ceramic has good high-temperature strength and thermal stability, can maintain good mechanical properties and chemical stability in a high-temperature environment, and the maximum working temperature thereof can reach 1700℃. When the corundum mullite ceramic is used as the inner side of the composite material, direct contact of the titanium alloy with the high-temperature flame in the flame tube is avoided, and therefore, the corundum mullite ceramic-titanium alloy composite material overcomes the flammability defect of titanium alloy. At the same time, the corundum mullite ceramic has excellent heat insulation performance, and the corundum mullite ceramic-titanium alloy composite material can work in an environment with a temperature higher than the conventional working temperature of titanium alloy. Therefore, the corundum mullite ceramic-titanium alloy composite material has higher temperature resistance than titanium alloy, and has a wider application range.
[0040] (2) High strength in high-temperature environment, good use effect
[0041] With the increase of temperature, the strength of TC4 titanium alloy decreases. The yield strength of titanium alloy is closely related to temperature, and with the increase of temperature, the crystal lattice structure of titanium alloy changes, which increases the crystal boundary slip and dislocation movement, thereby reducing the yield strength of the material. In addition, the deformation trend of titanium alloy at high temperatures may also cause the strength to decrease. Generally, when the temperature exceeds 400℃, the strength and hardness of titanium alloy gradually decrease, and the elongation increases.
[0042] The corundum mullite ceramic adopts artificial synthetic superfine mullite powder, has the characteristics of uniform expansion, excellent thermal shock resistance, high hot modulus of rupture, small high-temperature creep value, high hardness, good chemical corrosion resistance, etc. The bending strength of the corundum mullite ceramic at 1000 DEG C can reach 620 MPa, and the fracture toughness KIC can reach 5.9 MPa. With the increase of temperature, the strength and toughness not only do not decrease, but also increase significantly, which is an excellent characteristic of the corundum mullite ceramic as a high-temperature material.
[0043] Due to the addition of the corundum mullite ceramic, the corundum mullite ceramic-titanium alloy composite material also has the characteristics that the strength and toughness increase with the increase of temperature, and has good creep performance and high-temperature stability at high temperature, can withstand large thermal stress and strain, and is not easy to be brittle and deformed.
[0044] (3) Small density and light weight
[0045] The density of the corundum mullite ceramic material is about 1.5-1.7 g / cm 3 , and the density of the TC4 titanium alloy is 4.43 g / cm 3 . The density of the corundum mullite ceramic-titanium alloy composite material is tested to be 2.5-2.7 g / cm 3 .
[0046] The third object of the present application is to provide an application of the corundum mullite ceramic-titanium alloy composite material in manufacturing a rocket engine combustion cylinder, especially a flame cylinder.
[0047] Based on the characteristics of the corundum mullite ceramic-titanium alloy composite material, when it is used to manufacture a flame cylinder, it has the characteristics of high temperature resistance, non-flammability, wide application range, etc., and can overcome the use defects of the decrease of the strength of the titanium alloy at high temperature, and significantly improve the performance of the flame cylinder. Under the condition of the same size, the weight of the flame cylinder manufactured by the corundum mullite ceramic-titanium alloy composite material is reduced by 41.3% compared with the flame cylinder manufactured by the TC4 titanium alloy, which is more in line with the development trend of the light weight of the aero-engine.
[0048] The fourth object of the present application is to provide a manufacturing method of the corundum mullite ceramic-titanium alloy composite material, so as to obtain a corundum mullite ceramic-titanium alloy brazing composite structure with high connection strength and stable and reliable. Specifically, the manufacturing method comprises the following steps: using a brazing material and a brazing process to weld the corundum mullite ceramic layer and the titanium alloy layer together, so as to obtain the corundum mullite ceramic-titanium alloy composite material.
[0049] The brazing material includes Zr: 26-29%, Ni: 21-24%, Cu: 21-24% by mass percentage, and the balance is Ti; and can be represented by TiZrCuNi filler metal. The brazing material can be TiZrCuNi foil strip filler metal. If the thickness of the TiZrCuNi foil strip is less than 0.09 mm, it is easy to make the brazing seam too thin, which is not conducive to the combination of corundum mullite ceramic and titanium alloy; and if the thickness of the TiZrCuNi foil strip is more than 0.1 mm, it is easy to cause the brazing seam to be too thick, which wastes the filler metal. Therefore, the thickness of the TiZrCuNi foil strip is preferably 0.09-0.1 mm. The brazing material can also be TiZrCuNi amorphous filler metal or TiZrCuNi paste-like filler metal, etc. The TiZrCuNi filler metal can also be TiCrCuNi amorphous filler metal or TiCrCuNi paste-like filler metal, but the gap between TC4 titanium alloy and the above-mentioned corundum mullite ceramic needs to be controlled well during use.
[0050] The manufacturing method of the above-mentioned corundum mullite ceramic-titanium alloy composite material includes the following steps:
[0051] Component assembly and fixation: the above-mentioned corundum mullite ceramic material and titanium alloy are assembled and fixed together to form an assembly component;
[0052] Brazing heating: the assembly component is heated and welded by a vacuum brazing furnace to form the welded joint, and a composite material semi-finished product is prepared;
[0053] Cooling and post-processing: the composite material semi-finished product is cooled to room temperature and subjected to post-processing to prepare the corundum mullite ceramic-titanium alloy composite material.
[0054] The step of component assembly and fixation is a prior art, which can include: first, the above-mentioned corundum mullite ceramic and titanium alloy are assembled together, the TiZrCuNi foil strip filler metal is placed between the corundum mullite ceramic and the titanium alloy, and a certain position and distance are maintained; and then a clamp or a bracket and the like is used for fixation to ensure that no movement or deformation occurs during brazing, and an assembly component is obtained.
[0055] The brazing heating step comprises: placing the assembly component into a vacuum brazing furnace for heating and welding to form the welded joint, thereby obtaining a composite material semi-finished product. The welding heating temperature is selected in relation to the liquid phase temperature of the brazing material. According to the liquidus temperature of the brazing material TiZrCuNi, the heating temperature is preferably 1000-1050 DEG C. If the heating temperature is lower than 1000 DEG C, the brazing material is not completely melted. If the heating temperature is higher than 1050 DEG C, the heating temperature is too high, which affects the performance of the base material and the joint stress is large, thereby affecting the connection strength and reliability of the weld diffusion zone. The holding time is determined according to the TiZrCuNi brazing material and the base material. If the holding time is too short, the brazing joint is seriously segregated, the component distribution is uneven, and the strength of the weld diffusion zone is low. If the holding time is too long, the base material and the brazing material are excessively diffused, which affects the performance of the base material. Therefore, the holding time is preferably 20-30 min.
[0056] The cooling and post-processing step comprises: gradually cooling the composite material semi-finished product to room temperature; and performing trimming, polishing, cutting and other treatments on the brazing connection part, thereby obtaining a titanium alloy and ceramic composite material. During the cooling process, if the cooling rate is higher than 10 DEG C / min, the residual stress of the welded joint is too large. If the cooling rate is lower than 5 DEG C / min, the cooling time is too long and the preparation efficiency is too low. Therefore, the cooling rate is preferably 5 DEG C / min-10 DEG C / min.
[0057] The manufacturing method provided by the application brazes the corundum mullite ceramic and the titanium alloy together by using the vacuum brazing method, so that the corundum mullite ceramic and the titanium alloy are well brazed together at a high temperature of 1000 DEG C without pores and cracks. The structure of the ceramic side is dense, and there is no crack between the brazing joint area and the corundum mullite ceramic side. The overall strength of the composite material is 410-425 MPa, which has good mechanical strength, thermal shock resistance and high temperature resistance, and meets the manufacturing requirements of the flame tube of the combustion chamber of the aero-engine.
[0058] In the application, the apparent porosity is tested according to the light industry standard QB / T1642-2012, the bending strength is tested according to the standard GBT11363-brazing joint strength test method, the fracture toughness is tested according to the American Society for Testing and Materials standard ASTM C1421-01a standard test method for determining the fracture toughness of advanced ceramics at room temperature, the thermal expansion coefficient is tested according to the GBT 16535 engineering ceramic linear thermal expansion coefficient test method, and the thermal conductivity is tested according to the GB / T39862-2021 high thermal conductivity ceramic thermal conductivity detection.
[0059] The application will be further explained and described below with specific examples.
[0060] Example 1: corundum mullite ceramic material
[0061] The embodiment provides a corundum mullite ceramic material M1-M5, which takes corundum and mullite as main crystal phases, mainly takes corundum micro powder, mullite and ATM additives as raw materials, is uniformly mixed and sintered in a high-temperature kiln to form. The process parameters of the corundum mullite ceramic material M1-M5 are shown in Table 1. The purity of the corundum micro powder and the mullite in the embodiment is all above 99.9 %, and the corundum micro powder is fused corundum, and the mass ratio of aluminum titanate to mullite in the ATM additive is 13:7.
[0062] Table 1 Process parameters of the corundum mullite ceramic material M1-M5
[0063] Examples M1 M2 M3 M4 M5 Mullite to corundum mass ratio 55:45 60:40 60:40 60:40 65:35 ATM addition amount / % 0.4 0.3 0.4 0.5 0.4 Sintering temperature / °C 1825 1800 1825 1850 1825 Sintering time / h 3.5 3.5 3.5 3 3.5
[0064] The bending strength, shock resistance, fracture toughness, thermal expansion coefficient, thermal conductivity and the like of the corundum mullite ceramic M1-M5 are shown in Table 2.
[0065] Table 2 Performance test result table of the corundum mullite ceramic material
[0066]
[0067] As can be seen from Table 2, the apparent porosity of the corundum mullite ceramic provided in the embodiment is 28.4-33.5 %, the density is 3.78-3.99 g / cm 3 , the bending strength at room temperature is 528-584 MPa, the fracture toughness KIC at room temperature reaches 4.8-5.3 MPa, the thermal expansion coefficient is (5.3-6.7) x 10 -6 / ℃, the thermal conductivity is 9.8-13.7 W / (m·K), and the like, which meets the use requirements of the high-temperature-resistant material for the flame tube of the aero-engine combustion chamber.
[0068] The microstructure of the corundum mullite ceramic material M3 is shown in Figure 1 From Figure 1 , it can be clearly seen that the corundum mullite ceramic material M3 is composed of corundum phase and mullite phase, and both of them are uniformly distributed and have a dense structure.
[0069] The corundum mullite ceramics with different apparent porosities show different mechanical strengths, the corundum mullite ceramic materials with different apparent porosities are prepared by using the method provided in the embodiment through the control variable method, and the bending strength is tested, so as to screen and determine the appropriate corundum mullite ceramic material for the production of the flame tube. The apparent porosity and the bending strength of part of the test data are shown in Table 3, and the fitting results of the detection data are shown in Figure 2 Table 3. In Table 3, the "mass ratio" is the mass ratio of mullite to corundum.
[0070] Table 3 Corundum-mullite ceramic preparation process parameters and thermal shock resistance results table
[0071] Serial number Mass ratio Sintering temperature Sintering time Apparent porosity / % Bending strength test value / MPa 1 60:40 1825 3.5 28.4 584 2 60:40 1850 3 32.1 573 3 60:40 1800 3 36.3 529 4 60:40 1900 3 39.2 362 5 60:40 1950 3.5 42.1 247 6 60:40 2000 3 44.9 156 7 60:40 2000 3.5 47.8 144
[0072] From Table 3 and Figure 2 It can be seen that: the apparent porosity is in the range of 28.4%-47.8%, the bending strength of corundum-mullite ceramic first slowly decreases with the increase of apparent porosity, until the apparent porosity increases to about 36.3%, the bending strength sharply decreases, and when the apparent porosity increases to about 42.1%, the bending strength slowly decreases, and even tends to be stable. Combined with Table 3 and Figure 2 The bending strength change rule of corundum-mullite ceramic material is analyzed, and the performance evaluation of corundum-mullite ceramic material is comprehensively considered. When the mass ratio of mullite to corundum is 60:40, the ATM addition amount is 0.4%, the sintering temperature is 1825℃, and the sintering time is 3.5h, the mechanical and thermal properties of the corundum-mullite ceramic material M3 are the best.
[0073] From Figure 2 It can be seen that the fitting empirical formula of the thermal shock resistance R of the above corundum-mullite ceramic material and the apparent porosity x is:
[0074] R = 120 + 472 / (1 + exp((x-0.4) / dx));
[0075] Wherein: R is the bending strength at room temperature, MPa; x is the apparent porosity.
[0076] It is verified that the error between the test value and the calculated value of the bending strength in the above fitting formula is not more than ±3%, thereby proving the scientificity and rationality of the above fitting formula.
[0077] Example 2 Corundum-mullite ceramic-titanium alloy composite material and preparation method
[0078] This embodiment respectively provides a corundum-mullite ceramic-titanium alloy composite material S1-S5, which has a thickness of about 2mm, and is obtained by laminating together the corundum-mullite ceramic materials M1-M5 and TC4 titanium alloy through a brazing welding layer. Specifically, the corundum-mullite ceramic-titanium alloy composite materials S1-S5 are respectively in a cylindrical structure, each corundum-mullite ceramic material is used as an inner side material of a flame tube to form a corundum-mullite ceramic layer; the TC4 titanium alloy is used as an outer side material to form a titanium alloy layer; and each corundum-mullite ceramic layer is arranged in the inner layer of the titanium alloy layer to avoid direct contact of the titanium alloy with the high-temperature flame in the flame tube. The corresponding relationship between the corundum-mullite ceramic-titanium alloy composite materials S1-S5 and the corundum-mullite ceramic materials M1-M5 is: S1-M1, S2-M2, S3-M3, S4-M4, and S5-M5.
[0079] The embodiments respectively provide applications of the above corundum-mullite ceramic-titanium alloy composite materials S1-S5 in flame tubes.
[0080] The embodiments also respectively provide a manufacturing method of the corundum-mullite ceramic-titanium alloy composite materials S1-S5. The corundum-mullite ceramic-titanium alloy composite materials are mainly prepared by the following steps:
[0081] (1) Selection of raw materials: when the titanium alloy is used to manufacture the flame tube of the combustion chamber of the aero-engine, the thickness thereof is about 2 mm; the thickness of the corundum-mullite ceramic materials M1-M5 is 1 mm, and the thickness of the TC4 titanium alloy is 1 mm, wherein the high-purity corundum-mullite ceramic is used as the inner material of the flame tube, and the density thereof is 4.43 g / cm 3 ; and the TC4 titanium alloy is used as the outer material;
[0082] (2) Preparation of brazing material: when the TC4 titanium alloy and the corundum-mullite ceramic materials M1-M5 are brazed to be manufactured, the TiCrCuNi foil strip brazing material is selected, and the thickness thereof is 0.09-0.1 mm;
[0083] (3) Assembly and fixation: the above corundum-mullite ceramic materials M1-M5 and the TC4 titanium alloy are assembled together, the TiCrCuNi foil strip brazing material is placed between the corundum-mullite ceramic and the titanium alloy, the interval is kept to be 0.1 mm, and a clamp is used for fixation, so that movement or deformation of the assembly does not occur during brazing, and an assembly component is obtained;
[0084] (4) Brazing heating: the above assembly component is placed into a vacuum brazing furnace to be heated and brazed to form the welded joint, and after heating, a composite material semi-finished product is obtained; wherein the heating temperature is about 1025℃, the holding time is about 25 min, and the heating speed is 10℃ / min;
[0085] (5) Cooling and processing: first, the cooling speed is kept to be 5℃ / min-10℃ / min, so that the brazed semi-finished product of the composite material is gradually cooled to room temperature; and then the brazing connection part is processed, such as trimming and polishing, so that the connection quality meets the requirements, and the corundum-mullite ceramic-titanium alloy composite materials S1-S5 are prepared;
[0086] (6) Processing: according to the use requirements of the engine flame tube, the corundum-mullite ceramic-titanium alloy composite materials S1-S5 are processed into specific sizes.
[0087] Comparative examples
[0088] The comparative examples 1-4 each provide a corundum-mullite ceramic-titanium alloy composite material D1-D4, the brazing manufacturing method of which is the same as that provided in the embodiment 2, and the main difference is that different corundum-mullite ceramic materials are used, and the specific conditions are as follows:
[0089] The ordinary corundum mullite ceramic material DM1 of Comparative Example D1 has the same process parameters as the material M3 provided in Example 1, and the main difference is that DM1 uses natural corundum and natural kaolin as raw materials, and the apparent porosity of the corundum mullite ceramic material DM1 obtained is 48.1%;
[0090] The ordinary corundum mullite ceramic material DM2 of Comparative Example D2 has the same raw materials and process parameters as the material M3 provided in Example 1, and the main difference is that the mass ratio of mullite to corundum in DM2 is 50:50, and the apparent porosity of the corundum mullite ceramic material DM2 obtained is 35.2%;
[0091] The ordinary corundum mullite ceramic material DM3 of Comparative Example D3 has the same raw materials and process parameters as the material M3 provided in Example 1, and the main difference is that the mass ratio of mullite to corundum in DM2 is 70:30, and the apparent porosity of the corundum mullite ceramic material DM3 obtained is 39.7%;
[0092] The ordinary corundum mullite ceramic material DM4 of Comparative Example D4 has the same raw materials and process parameters as the material M3 provided in Example 1, and the main difference is that the sintering temperature of the mullite and corundum mixture is 1750℃, and the apparent porosity of the corundum mullite ceramic material DM4 obtained is 42.5%;
[0093] The ordinary corundum mullite ceramic material DM5 of Comparative Example D5 has the same raw materials and process parameters as the material M3 provided in Example 1, and the main difference is that the sintering temperature of the mullite and corundum mixture is 1900℃, and the apparent porosity of the corundum mullite ceramic material DM5 obtained is 43.6%;
[0094] The ordinary corundum mullite ceramic material DM6 of Comparative Example D6 has the same raw materials and process parameters as the material M3 provided in Example 1, and the main difference is that the sintering time of the mullite and corundum mixture is 2.5h, and the apparent porosity of the corundum mullite ceramic material DM6 obtained is 36.4%;
[0095] The ordinary corundum mullite ceramic material DM7 of Comparative Example D7 has the same raw materials and process parameters as the material M3 provided in Example 1, and the main difference is that the sintering time of the mullite and corundum mixture is 4h, and the apparent porosity of the corundum mullite ceramic material DM7 obtained is 36.8%.
[0096] 1) Titanium alloy composite material performance test
[0097] The density, overall mechanical properties and thermal properties of the ceramic-titanium alloy composite materials S1-S5 and D1-D7 described above were tested, and the results are shown in Table 4.
[0098] Table 4 Test results of titanium alloy composite materials at room temperature (25℃)
[0099] Sample Density g / cm 3 ]] Bending strength / MPa Fracture toughness / MPa Thermal conductivity W / (m K) S1 4.16 531 5.2 8.9 S2 4.14 528 5.3 10.1 S3 4.25 584 4.8 9.65 S4 4.18 573 5.0 10.2 S5 4.19 580 4.9 10.9 D1 3.94 98 -- 7.2 D2 4.14 496 5.3 10.1 D3 4.07 332 4.2 8.15 D4 4.02 281 3.8 7.85 D5 4.01 275 3.9 7.75 D6 4.12 485 5.1 9.9 D7 4.11 476 5.0 9.75
[0100] As can be seen from Table 4, compared with the titanium alloy composite materials D1-D7 of the comparative examples using alumina ceramic insulating materials, the corundum mullite ceramic materials used in the titanium alloy composite materials S1-S5 of the embodiments as high-temperature materials make the density of the overall titanium alloy composite materials at room temperature reach 4.14-4.25 g / cm 3 , the bending strength reach 528-584 MPa, the fracture toughness KIC reach 4.8-5.3 MPa, the thermal conductivity reach 8.99-10.9 W / (m·K), etc., meeting the use requirements of the flame tube of the combustion chamber of the aero-engine on the high-temperature resistant materials, and the comprehensive performance of the corundum mullite ceramic-titanium alloy composite material S3 is the best.
[0101] Under the same conditions, the apparent porosity of the common corundum mullite ceramic material DM1 prepared by using natural corundum and natural kaolin in the comparative example D1 reaches 48.1%, and the bending strength is only 98 MPa, which is difficult to meet the use requirements of the corundum mullite ceramic in the field of the combustion chamber of the aero-engine; while the high-purity raw materials used in the embodiments of the present application can meet the use requirements of the corundum mullite ceramic in the field of the combustion chamber of the aero-engine.
[0102] In terms of the mass ratio of mullite to corundum, compared with the titanium alloy composite material S3 using the material M3, the mass ratio of corundum to mullite in the material DM2 used in the comparative example D2 is less than 55:45, the density of the overall titanium alloy composite material D2 is reduced, but the apparent porosity is obviously larger, and the bending strength is obviously decreased; the mass ratio of corundum to mullite in the material DM3 used in the comparative example D3 is greater than 65:35, the density of the overall titanium alloy composite material D3 is reduced, but the apparent porosity is obviously larger, and the bending strength, the fracture toughness and the thermal conductivity are obviously decreased, which are all difficult to meet the use requirements of the corundum mullite ceramic in the field of the combustion chamber of the aero-engine, so the addition amount of corundum to mullite in the corundum mullite ceramic material provided by the present application is 55-65:35-45.
[0103] In terms of the sintering temperature, compared with the titanium alloy composite material S3 using the material M3, the sintering temperature of the material DM4 used in the comparative example D4 is less than 1800℃, and the sintering temperature of the material DM5 used in the comparative example D5 is greater than 1850℃, the density of the titanium alloy composite materials D4 and D5 is reduced, but the apparent porosity of both is obviously larger, and the bending strength, the fracture toughness and the thermal conductivity are significantly decreased, which are all difficult to meet the use requirements of the corundum mullite ceramic in the field of the combustion chamber of the aero-engine, so the sintering temperature of the corundum mullite ceramic material provided by the present application is 1800-1850℃.
[0104] In terms of sintering time, the sintering time of the material DM6 used in the comparative example D6 is less than 3h, the sintering time of the material DM6 used in the comparative example D6 is greater than 3.5h, the density of the titanium alloy composite materials D6 and D7 is reduced, but the apparent porosity of the two is obviously larger, and the bending strength is significantly reduced, and both of them are difficult to meet the use requirements of corundum mullite ceramics in the field of aero-engine combustion chamber, therefore, the sintering time of the corundum mullite ceramic material provided by the present application is 3-3.5h.
[0105] 2) Welding diffusion zone structure of composite material
[0106] The microstructure of the welding diffusion zone of the ceramic-titanium alloy composite material S3 and D1 is photographed by using a scanning electron microscope (SEM) equipped with an energy dispersive spectrometer (EDS), and the results are shown in Figure 3 and Figure 4 .
[0107] It can be seen from Figure 3 that: in the corundum mullite ceramic-titanium alloy composite material S3, the corundum mullite ceramic is well bonded with the titanium alloy by brazing, and there is no pore and crack; the structure on the ceramic side is dense.
[0108] Figure 4 It is shown that: in the ordinary corundum mullite ceramic-titanium alloy composite material D1, the ordinary corundum mullite ceramic is well bonded with the titanium alloy composite material by brazing, and there is no pore and crack; the structure on the ceramic side is not dense, a large number of holes and cracks appear, and the apparent porosity is high.
[0109] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application and not to limit it; although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the specific embodiments of the present application can be modified or some technical features can be replaced by equivalent ones; without departing from the spirit of the technical solutions of the present application, they should be covered in the technical solution range of the present application.
Claims
1. A corundum mullite ceramic material, characterized in that, The corundum-mullite ceramic material is mainly made of corundum micropowder and mullite particles by high-temperature sintering, and the corundum micropowder is filled in the mullite particles in the high-temperature sintering process; the corundum-mullite ceramic material has a bending strength ≥550 MPa, an apparent porosity ≤35%, and a bulk density of 1.55-1.65 g / cm³. Preferably, the mullite particles have a chemical formula of 3Al2O3·2SiO2, the corundum micropowder mainly contains α-Al2O3, and the purity of the mullite particles and the corundum micropowder is ≥99.5%.
2. The corundum mullite ceramic material according to claim 1, characterized in that The relationship between the apparent porosity and the bending strength of the corundum-mullite ceramic material satisfies the following formula: R = 120 + 472 / (1 + exp((x-0.4) / dx)) wherein R is the bending strength, MPa; and x is the apparent porosity.
3. Corundum-mullite ceramic material according to claim 1 or 2, characterized in that The apparent porosity is 28-35%, the density is 3.78-3.99 g / cm3, the bending strength is 528-584 MPa, the fracture toughness KIC at room temperature reaches 4.8-5.3 MPa, the thermal expansion coefficient is (5.3-6.7) x 10 -6 / ℃, and the thermal conductivity is 9.8-13.7 W / (m K). Preferably, the mass ratio of the mullite particles to the corundum micropowder is 55-65:35-45 by 100 parts by mass. Preferably, the particle size of the mullite particles is 72-100 mesh, and the particle size of the corundum micropowder is 200-240 mesh. Preferably, 0.3-0.5% of ATM additive is further added in the high-temperature sintering process, wherein the ATM additive is an aluminum titanate-mullite composite material, and the mass ratio of the aluminum titanate to the mullite is 6:4-7:
3.
4. Corundum-mullite ceramic material according to claim 1 or 2, characterized in that The sintering temperature is 1800-1850°C, and the sintering time is 3-3.5 h.
5. A corundum-mullite ceramic-titanium alloy composite material, characterized by, The corundum-mullite ceramic-titanium alloy composite material comprises a titanium alloy layer and a corundum-mullite ceramic layer which is brazed on the surface of the titanium alloy layer, and the corundum-mullite ceramic layer is composed of the corundum-mullite ceramic material according to any one of claims 1-4. Preferably, the titanium alloy layer and the corundum-mullite ceramic layer are both in a cylindrical structure; more preferably, the corundum-mullite ceramic layer is welded on the inner layer of the titanium alloy layer. Preferably, the overall strength of the corundum-mullite ceramic-titanium alloy composite material is 410-425 MPa. Preferably, the overall density of the corundum-mullite ceramic-titanium alloy composite material is 4.14-4.25 g / cm³, the bending strength is 528-584 MPa, the fracture toughness KIC is 4.8-5.3 MPa, and the thermal conductivity is 8.99-10.9 W / (m·K).
6. The application of the corundum-mullite ceramic-titanium alloy composite material according to claim 5 in a flame tube.
7. A manufacturing method of the corundum-mullite ceramic-titanium alloy composite material according to claim 5, comprising the following steps: using a brazing material and a brazing process to weld the corundum-mullite ceramic layer and the titanium alloy layer together to obtain the corundum-mullite ceramic-titanium alloy composite material. Preferably, the brazing material comprises, in mass percent, Zr: 26-29%, Ni: 21-24%, Cu: 21-24%, with the balance being Ti; wherein, The brazing material is a foil, an amorphous filler metal, or a paste filler metal. Preferably, the titanium alloy is a TC4 titanium alloy.
8. The manufacturing method according to claim 7, wherein The manufacturing method comprises the following steps: Component assembly and fixation: assembling and fixing the corundum-mullite ceramic material and the titanium alloy together to form an assembly component; Brazing heating: heating and welding the assembly component in a vacuum brazing furnace to form a welded joint, thereby obtaining a composite material semi-finished product. Cooling and post-processing: cooling the composite semi-finished product to room temperature and performing post-processing to obtain the corundum-mullite ceramic-titanium alloy composite material.
9. The brazing manufacturing method according to claim 8, characterized by In the step of brazing heating, the heating temperature is 1000-1050℃, and the holding time is 20-30 min.
10. The brazing manufacturing method according to claim 8 or 9, characterized in that, The step of cooling and post-processing: first gradually cooling the composite semi-finished product to room temperature; and then performing trimming, polishing and cutting on the brazing joint to obtain the titanium alloy-ceramic composite material. Preferably, the cooling rate during the cooling process is 5-10℃ / min.