A method for ultrafast low-damage pre-oxidation assisted brazing of carbon fiber reinforced composites

Abstract

The application discloses a method for superfast low-damage pre-oxidation assisted brazing of carbon fiber reinforced composites, and relates to a method for pre-oxidation assisted brazing of carbon fiber reinforced composites. The application aims at solving the problems of large overall thermal damage of carbon fiber reinforced composites, low efficiency and high cost in a traditional muffle furnace pre-oxidation process. The method comprises the following steps: one, superfast low-damage pre-oxidation of carbon fiber reinforced composites; and two, brazing. The application is used for superfast low-damage pre-oxidation assisted brazing of carbon fiber reinforced composites.

Description

Technical Field

[0001] This invention relates to a method for pre-oxidation-assisted brazing of carbon fiber reinforced composite materials. Background Technology

[0002] To improve the mechanical properties of brazed joints of carbon fiber reinforced composites, surface treatments are typically applied to the carbon fiber reinforced composites, such as creating groove structures through mechanical drilling or laser etching. The brazing filler metal penetrating into the groove structure significantly increases the contact area between the filler metal and the base material, forming a pinned structure. In recent years, a novel method for pre-oxidizing carbon fiber reinforced composites has been developed. For example, in C / C composites, because the pyrolytic carbon matrix has different oxidation resistance than the carbon fiber, the pyrolytic carbon matrix of the C / C composite is oxidized at a certain temperature, while the carbon fiber is retained, forming a root-like pinned structure. However, traditional oxidation is usually carried out in a muffle furnace, requiring the entire base material to be immersed in a high-temperature oxidizing atmosphere. While this method can improve the mechanical strength of the joint, it also causes severe oxidative damage to the base material, leading to a decline in its properties. Summary of the Invention

[0003] This invention aims to address the problems of significant overall thermal damage, low efficiency, and high cost in the traditional muffle furnace pre-oxidation process for carbon fiber reinforced composite materials, and provides a method for ultra-fast, low-damage pre-oxidation-assisted brazing of carbon fiber reinforced composite materials.

[0004] A method for ultra-fast, low-damage pre-oxidation assisted brazing of carbon fiber reinforced composite materials comprises the following steps:

[0005] I. Ultra-fast, low-damage pre-oxidation of carbon fiber reinforced composites:

[0006] Two ends of the sheet-like carbon-based material are fixed to the positive and negative electrodes respectively. Then, the carbon fiber reinforced composite material is placed on the sheet-like carbon-based material, and the surface of the carbon fiber reinforced composite material to be brazed is in contact with the surface of the sheet-like carbon-based material. Under the conditions of air atmosphere and DC power supply current of 10A to 100A, the Joule heat generated by the sheet-like carbon-based material is used to pre-oxidize the surface of the carbon fiber reinforced composite material to be brazed until the sheet-like carbon-based material breaks and the pre-oxidation stops, thus obtaining the pre-oxidized carbon fiber reinforced composite material.

[0007] II. Brazing:

[0008] The pre-oxidized carbon fiber reinforced composite material, solder foil, and base material to be soldered are assembled to obtain an assembly, under a vacuum degree ≤10. -2 Under conditions of Pa and a heating rate of 5℃ / min to 25℃ / min, the brazing temperature is raised to 300℃ to 1500℃, and then the brazing is carried out under a vacuum of ≤10℃. -2Under the conditions of Pa and brazing temperature of 300℃~1500℃, the temperature is held for 1min~60min, and finally cooled, thus completing the method of ultra-fast low-damage pre-oxidation assisted brazing of carbon fiber reinforced composite materials.

[0009] The beneficial effects of this invention are:

[0010] 1. This invention helps reduce damage to carbon fiber reinforced composites. When the Joule heating of the sheet-like carbon-based material is used as a heat source, a non-uniform temperature field is formed on the surface of the carbon fiber reinforced composite. The side of the carbon fiber reinforced composite in contact with the heat source is at a high temperature, while the side away from the heat source is at a low temperature. This results in significant oxidation of the surface of the carbon fiber reinforced composite in contact with the heat source, while the surface of the carbon fiber reinforced composite away from the heat source experiences less oxidation damage. Brazing the pre-oxidized carbon fiber reinforced composite allows the brazing filler metal to penetrate into the oxidation pores, healing the oxidation pores and increasing the connection area between the brazing filler metal and the carbon fiber reinforced composite, forming a pinned structure and improving mechanical properties. For example, in Example 1, the temperature of the C / C composite material 10 mm away from the heat source is below 800°C, and its surface morphology is similar to that of the original C / C composite material, with no obvious oxidation pores. The temperature of the C / C composite material on the side in contact with the heat source is above 1200°C, and annular oxidation pores appear on the surface.

[0011] 2. This invention utilizes the inherent oxidation fracture of carbon-based materials to forcibly terminate the test, providing a more controllable process parameter adjustment strategy. Traditional strategies use energizing time and current as parameters for thermal shock, resulting in low test stability. This invention uses the upper limit of carbon-based material oxidation (which depends on material type and size) as a controllable variable, leading to greater test stability. Due to the rapid speed and extremely short duration of thermal shock, and the influence of uncontrollable factors such as equipment control precision and the degree of contact between the fixture and the carbon-based material, the temperature of the heat source can still deviate by 100℃ to 500℃ under identical current and energizing time conditions in actual tests. Therefore, using traditional current and time as variable control parameters leads to unstable test results. This invention utilizes the inherent oxidation fracture characteristics of carbon-based materials as a heat source, using the size of the carbon-based material as a crucial variable in the test, and innovatively uses the fracture of the carbon-based material as the marker for the end of the actual test. Since both carbon-based materials and carbon fiber reinforced composites undergo oxidation, in repeatable tests, when carbon-based materials of uniform specifications undergo oxidation fracture, the oxidation degree of the carbon fiber reinforced composite will also remain consistent. When carbon-based materials are used as a heat source, they can oxidize in high-temperature environments. When the oxidation limit of the carbon-based material is reached, the carbon-based material fractures, forcibly terminating the oxidation of the carbon fiber reinforced composite. Since the oxidation limit of the same size and type of carbon-based material is a constant and controllable variable, it can replace unstable parameters such as energizing time and current.

[0012] 3. This invention helps reduce production costs and energy consumption. Traditional pre-oxidation in muffle furnaces primarily utilizes thermal radiation from resistive elements within the furnace cavity for heating, typically at power levels ranging from several kilowatts to tens of kilowatts. This method uses relatively little energy to heat carbon fiber reinforced composite materials, with most of the energy dissipated into the environment, which is detrimental to energy conservation and emission reduction. This invention uses the Joule heating of sheet-like carbon-based materials as a heat source; the pre-oxidation power in Example 1 is less than 800W, significantly improving energy utilization.

[0013] 4. This invention helps improve production efficiency. Traditional muffle furnace pre-oxidation has a long total processing time. This invention can significantly reduce preheating time; for example, pre-oxidation in Example 1 is less than 30 seconds. Therefore, this method can reduce the total processing time and improve pre-oxidation efficiency.

[0014] This invention relates to a method for ultra-fast, low-damage pre-oxidation assisted brazing of carbon fiber reinforced composite materials.

[0015] Instruction manual illustrations

[0016] Figure 1 This is a schematic diagram of step one, ultra-fast low-damage pre-oxidation, of the present invention;

[0017] Figure 2 The image shows the surface morphology of the pre-oxidized carbon fiber reinforced composite material prepared in step one of Example 1 (first group of experiments);

[0018] Figure 3 The image shows the surface morphology of the pre-oxidized carbon fiber reinforced composite material prepared in step one of Example 1 (second group of experiments);

[0019] Figure 4 The surface morphology of the C / C composite material at a distance of 10 mm from the heat source (first group of experiments). Detailed Implementation

[0020] Specific Implementation Method 1: This implementation method provides an ultra-fast, low-damage, pre-oxidation-assisted brazing method for carbon fiber reinforced composite materials, which is carried out according to the following steps:

[0021] I. Ultra-fast, low-damage pre-oxidation of carbon fiber reinforced composites:

[0022] Two ends of the sheet-like carbon-based material are fixed to the positive and negative electrodes respectively. Then, the carbon fiber reinforced composite material is placed on the sheet-like carbon-based material, and the surface of the carbon fiber reinforced composite material to be brazed is in contact with the surface of the sheet-like carbon-based material. Under the conditions of air atmosphere and DC power supply current of 10A to 100A, the Joule heat generated by the sheet-like carbon-based material is used to pre-oxidize the surface of the carbon fiber reinforced composite material to be brazed until the sheet-like carbon-based material breaks and the pre-oxidation stops, thus obtaining the pre-oxidized carbon fiber reinforced composite material.

[0023] II. Brazing:

[0024] The pre-oxidized carbon fiber reinforced composite material, solder foil, and base material to be soldered are assembled to obtain an assembly, under a vacuum degree ≤10. -2 Under conditions of Pa and a heating rate of 5℃ / min to 25℃ / min, the brazing temperature is raised to 300℃ to 1500℃, and then the brazing is carried out under a vacuum of ≤10℃. -2 Under the conditions of Pa and brazing temperature of 300℃~1500℃, the temperature is held for 1min~60min, and finally cooled, thus completing the method of ultra-fast low-damage pre-oxidation assisted brazing of carbon fiber reinforced composite materials.

[0025] Figure 1 This is a schematic diagram of the ultra-fast, low-damage pre-oxidation process in step one of this invention. As shown in the diagram, using sheet-like carbon-based material as a heat source, a direct current is passed through the conductive sheet-like carbon-based material, and heat is applied to the carbon fiber reinforced composite material via thermal conduction, causing oxidation of the surface of the carbon fiber reinforced composite material. During the pre-oxidation process, only the surface in contact with the sheet-like carbon-based material experiences a higher temperature, resulting in the formation of annular gaps. Due to the limited heat penetration capability of the sheet-like carbon-based material, the temperature is lower at locations farther from it, resulting in less pre-oxidation damage and thus less overall thermal damage to the material.

[0026] The beneficial effects of this embodiment are:

[0027] 1. This embodiment helps reduce damage to carbon fiber reinforced composites. When the Joule heating of the sheet-like carbon-based material is used as a heat source, a non-uniform temperature field is formed on the surface of the carbon fiber reinforced composite. The side of the carbon fiber reinforced composite in contact with the heat source is at a high temperature, while the side away from the heat source is at a low temperature. This results in significant oxidation of the surface of the carbon fiber reinforced composite in contact with the heat source, while the surface of the carbon fiber reinforced composite away from the heat source experiences less oxidation damage. Brazing the pre-oxidized carbon fiber reinforced composite allows the brazing filler metal to penetrate into the oxidation pores, healing the oxidation pores and increasing the connection area between the brazing filler metal and the carbon fiber reinforced composite, forming a pinned structure and improving mechanical properties. For example, in Example 1, the temperature of the C / C composite material 10 mm away from the heat source is below 800°C, and its surface morphology is similar to that of the original C / C composite material, with no obvious oxidation pores. The temperature of the C / C composite material on the side in contact with the heat source is above 1200°C, and annular oxidation pores appear on the surface.

[0028] 2. This embodiment utilizes the characteristic of carbon-based materials undergoing self-oxidation fracture to forcibly terminate the test, providing a more controllable process parameter adjustment strategy. Traditional strategies use energizing time and current as parameters for thermal shock, resulting in low test stability. This embodiment, however, uses the upper limit of carbon-based material self-oxidation (which depends on the material type and size) as a controllable variable, leading to stronger test stability. Due to the rapid speed and extremely short duration of thermal shock, and the influence of uncontrollable factors such as equipment control precision and the degree of contact between the fixture and the carbon-based material, the temperature of the heat source can still deviate by 100℃ to 500℃ under identical current and energizing time conditions in actual tests. Therefore, using traditional current and time as variable control parameters leads to unstable test results. This embodiment utilizes the self-oxidation fracture characteristics of the carbon-based material heat source, using the size of the carbon-based material as an important variable in the test, and innovatively uses the fracture of the carbon-based material as the marker for the end of the actual test. Since both carbon-based materials and carbon fiber reinforced composites undergo oxidation, in repeatable tests, when carbon-based materials of uniform specifications undergo oxidation fracture, the oxidation degree of the carbon fiber reinforced composite will also remain consistent. When carbon-based materials are used as a heat source, they can oxidize in high-temperature environments. When the oxidation limit of the carbon-based material is reached, the carbon-based material fractures, forcibly terminating the oxidation of the carbon fiber reinforced composite. Since the oxidation limit of the same size and type of carbon-based material is a constant and controllable variable, it can replace unstable parameters such as energizing time and current.

[0029] 3. This implementation method helps reduce production costs and energy consumption. Traditional pre-oxidation in muffle furnaces primarily utilizes thermal radiation from resistive elements within the furnace cavity for heating, typically at power levels ranging from several kilowatts to tens of kilowatts. This method uses relatively little energy to heat carbon fiber reinforced composite materials, with most of the energy dissipated into the environment, which is detrimental to energy conservation and emission reduction. This implementation method uses the Joule heating of sheet-like carbon-based materials as the heat source; the pre-oxidation power in Example 1 is less than 800W, significantly improving energy utilization.

[0030] 4. This implementation method helps improve production efficiency. Traditional muffle furnace pre-oxidation has a long total processing time. This implementation method can significantly reduce preheating time; for example, pre-oxidation in Example 1 is less than 30 seconds. Therefore, this method can reduce the total processing time and improve pre-oxidation efficiency.

[0031] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the sheet-like carbon-based material mentioned in step one is carbon cloth, carbon paper, carbon felt, graphite felt, graphene film, carbon nanotube film, or carbon fiber film. Everything else is the same as in Specific Implementation Method One.

[0032] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One or Two in that: the upper surface area of ​​the sheet-like carbon-based material in step one is larger than the brazing surface of the carbon fiber reinforced composite material, and the thickness of the sheet-like carbon-based material is 1mm to 8mm. Everything else is the same as in Specific Implementation Method One or Two.

[0033] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that the carbon fiber reinforced composite material mentioned in step one is a C / C composite material, a C / SiC composite material, or a C / C-SiC composite material. Everything else is the same as in Specific Implementation Methods One to Three.

[0034] Specific Implementation Method Five: This implementation method differs from Specific Implementation Methods One to Four in that: in step one, under the conditions of an air atmosphere and a DC power supply current of 10A to 100A, the Joule heating generated by the sheet-like carbon-based material causes the surface temperature of the sheet-like carbon-based material to reach 800℃ to 2000℃. Everything else is the same as in Specific Implementation Methods One to Four.

[0035] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that it utilizes an infrared thermometer, infrared thermal imager, or thermocouple to test the surface temperature of the sheet-like carbon-based material. Otherwise, it is the same as Specific Implementation Methods One to Five.

[0036] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods One to Six in that the solder foil mentioned in step two is AgCuTi solder, SnAgCu solder, AgCuInTi solder, TiZrNiCu solder, TiCu solder, SnAgCu solder, BNi2 solder, or BNi5 solder. Everything else is the same as in Specific Implementation Methods One to Six.

[0037] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods One to Seven in that the thickness of the solder foil mentioned in step two is 50 micrometers to 200 micrometers. Everything else is the same as in Specific Implementation Methods One to Seven.

[0038] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods One to Eight in that the base material to be welded in step two is a pre-oxidized C / C composite material, a pre-oxidized C / SiC composite material, a pre-oxidized C / C-SiC composite material, titanium alloy, stainless steel, nickel-based alloy, niobium metal, aluminum alloy, alumina ceramic, zirconium oxide ceramic, graphite, or silicon carbide ceramic. Everything else is the same as in Specific Implementation Methods One to Eight.

[0039] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Methods One to Nine in that: in step two, furnace cooling is used or the cooling rate is 5℃ / min to 25℃ / min. Everything else is the same as Specific Implementation Methods One to Nine.

[0040] The beneficial effects of the present invention are verified using the following embodiments:

[0041] Example 1:

[0042] A method for ultra-fast, low-damage pre-oxidation assisted brazing of carbon fiber reinforced composite materials comprises the following steps:

[0043] I. Ultra-fast, low-damage pre-oxidation of carbon fiber reinforced composites:

[0044] Two ends of the sheet-like carbon-based material are fixed to the positive and negative electrodes respectively. Then, the carbon fiber reinforced composite material is placed on the sheet-like carbon-based material, and the surface of the carbon fiber reinforced composite material to be brazed is in contact with the surface of the sheet-like carbon-based material. Under the conditions of air atmosphere and DC power supply current of 30A, the Joule heat generated by the sheet-like carbon-based material is used to pre-oxidize the surface of the carbon fiber reinforced composite material to be brazed until the sheet-like carbon-based material breaks and the pre-oxidation stops, thus obtaining the pre-oxidized carbon fiber reinforced composite material.

[0045] II. Brazing:

[0046] The pre-oxidized carbon fiber reinforced composite material, solder foil, and base material to be soldered are assembled to obtain an assembly, which is then subjected to a vacuum of 10... -3 Under the conditions of Pa and a heating rate of 15℃ / min, the brazing temperature was raised to 750℃, and then the brazing was performed under a vacuum of 10... -3 Under the conditions of Pa and a brazing temperature of 750℃, the temperature is held for 10 minutes, and then cooled at a rate of 5℃ / min. This completes the method of ultra-fast, low-damage pre-oxidation assisted brazing of carbon fiber reinforced composite materials, resulting in pre-oxidation assisted carbon fiber reinforced composite material / TC4 titanium alloy welded parts.

[0047] The sheet-like carbon-based material mentioned in step one is graphite felt, with dimensions of 15mm × 30mm × 4mm (thickness).

[0048] The carbon fiber reinforced composite material mentioned in step one is a three-dimensional woven C / C composite material with dimensions of 5mm × 5mm × 10mm (thickness).

[0049] The carbon fiber reinforced composite material mentioned in step one is a pretreated carbon fiber reinforced composite material, and the pretreatment is carried out according to the following steps: the carbon fiber reinforced composite material is polished, and then ultrasonically cleaned with ethanol and deionized water respectively to remove surface impurities.

[0050] In step one, the equipment parameters are set to 30A / 30s (equipment setting value). Under the conditions of air atmosphere and DC power supply current of 30A, the Joule heat generated by the sheet carbon-based material is measured by using an infrared thermometer to test the surface temperature of the sheet carbon-based material.

[0051] The solder foil mentioned in step two is an AgCuInTi solder with a thickness of 80 micrometers.

[0052] The base material to be welded in step two is TC4 titanium alloy with dimensions of 10mm × 10mm × 3mm (thickness).

[0053] Under the test conditions of Example 1, the pre-oxidation power was 634W.

[0054] Two repeated experiments were conducted according to the process in Example 1. At 30A / 30s (equipment setpoint), due to uncontrollable factors, the peak temperatures of the same-sized graphite felt in the two experiments were 1532℃ (first group experiment) and 1715℃ (second group experiment), respectively. This indicates that even with the same current and time, different heat source temperatures can occur, leading to low experimental stability. However, graphite felt of the same size as a heat source has the same upper limit for oxidation resistance; it will break when oxidized to the same degree, which also results in the same degree of oxidation in the carbon fiber reinforced composite material on the graphite felt. The peak temperature in the first group experiment was lower than that in the second group experiment. In the first group, oxidation and fracture of the graphite felt occurred at 28s, forcibly stopping the experiment. In the second group experiment, the temperature was higher, and oxidation and fracture occurred at 23s, forcibly stopping the experiment. This strategy, despite the different temperatures and times, can ensure that the carbon fiber reinforced composite material exhibits the same degree of oxidation, making the effect more controllable.

[0055] In the first set of experiments, the weight loss rate of the pre-oxidized carbon fiber reinforced composite material prepared in step one was 2.38%. In the second set of experiments, the weight loss rate of the pre-oxidized carbon fiber reinforced composite material prepared in step one was 2.31%. Within the error range, the two can be considered to have no significant difference, indicating that the control strategy is effective. However, when the C / C composite material was placed in a uniform high-temperature environment (1200℃ / 30s) for oxidation, the C / C composite material showed overall oxidation damage, with a weight loss rate of 5.3%.

[0056] Figure 2 The image shows the surface morphology of the pre-oxidized carbon fiber reinforced composite material prepared in step one of Example 1 (first group of experiments); Figure 3 The image shows the surface morphology of the pre-oxidized carbon fiber reinforced composite material prepared in step one of Example 1 (second group of experiments). As can be seen from the image, the matrix in the C / C composite material is significantly oxidized and corroded, forming annular pores. The formation of these annular oxidation pores depends on the preferential oxidation of the carbon matrix at high temperatures. The oxidized carbon matrix first forms a microgroove structure, which provides channels for oxygen diffusion, thus intensifying the oxidation of the carbon matrix. The size of the oxidation pores is limited by the reaction rate between the carbon matrix and oxygen. As the temperature increases, the oxidation intensifies, and the oxidation pores gradually expand from the surface layer to the deeper layers of the material. Furthermore, as shown in the image, there is no significant difference in morphology after the two sets of repeated experiments, indicating that the control strategy is effective.

[0057] Comparative Experiment: This comparative experiment differs from Example 1 in that the pre-oxidation in step one is omitted, and step two yields a carbon fiber reinforced composite material / TC4 titanium alloy welded part. Everything else is the same as in Example 1.

[0058] After oxidation, the solder penetrates into the annular gap, forming a pinned structure. This structure effectively increases the contact area between the solder and the base material, hindering crack propagation. Furthermore, the properties of the solder-penetrated zone are intermediate between those of the base material and the solder, forming a transition zone that effectively alleviates the problem of mismatched thermal expansion coefficients. Additionally, the pre-oxidation current has a significant impact on the mechanical properties of the C / C composite material and the TC4 joint. As the current increases, the strength initially increases and then decreases.

[0059] Under a shear rate of 0.5 mm / min, the shear strength of the carbon fiber reinforced composite / TC4 titanium alloy welded joint in the comparative experiment was 13.4 MPa. The joint strength of the pre-oxidation assisted carbon fiber reinforced composite / TC4 titanium alloy welded joint (first group of tests) in Example 1 reached 25.1 MPa. The joint strength of the pre-oxidation assisted carbon fiber reinforced composite / TC4 titanium alloy welded joint (second group of tests) in Example 1 reached 25.5 MPa. The average joint strength of the two groups of tests was 25.3 MPa.

[0060] Due to the limited penetration ability of graphite felt into C / C composite materials, the surface temperature of the C / C composite material on the graphite felt side exceeds 1200℃, resulting in good oxidation and corrosion effects. At a distance of 10mm from the heat source, the C / C composite material resembles its original morphology, such as... Figure 4 As shown, Figure 4 The image shows the surface morphology of the C / C composite material at a distance of 10 mm from the heat source (first group of experiments). Tests showed that the peak temperature at 10 mm from the heat source was 765℃, and the peak temperature at 3 mm from the heat source was 1325℃. This indicates that this method selectively oxidizes only the C / C composite material near the heat source, while the overall oxidation damage to the C / C composite material is relatively small.

Claims

1. A method for ultra-fast, low-damage pre-oxidation assisted brazing of carbon fiber reinforced composite materials, characterized in that... It is done in the following steps: I. Ultra-fast, low-damage pre-oxidation of carbon fiber reinforced composites: Two ends of the sheet-like carbon-based material are fixed to the positive and negative electrodes respectively. Then, the carbon fiber reinforced composite material is placed on the sheet-like carbon-based material, and the surface of the carbon fiber reinforced composite material to be brazed is in contact with the surface of the sheet-like carbon-based material. Under the conditions of air atmosphere and DC power supply current of 30A, the Joule heat generated by the sheet-like carbon-based material is used to pre-oxidize the surface of the carbon fiber reinforced composite material to be brazed until the sheet-like carbon-based material breaks and the pre-oxidation stops, thus obtaining the pre-oxidized carbon fiber reinforced composite material. II. Brazing: The pre-oxidized carbon fiber reinforced composite material, solder foil, and base material to be soldered are assembled to obtain an assembly, which is then subjected to a vacuum of 10... -3 Under the conditions of Pa and a heating rate of 15℃ / min, the brazing temperature was raised to 750℃, and then the brazing was performed under a vacuum of 10... -3 Under the conditions of Pa and brazing temperature of 750℃, the temperature is held for 10 minutes, and then cooled down at a rate of 5℃ / min. This completes the method of ultra-fast low-damage pre-oxidation assisted brazing of carbon fiber reinforced composite material, and obtains pre-oxidation assisted carbon fiber reinforced composite material / TC4 titanium alloy welded parts. The sheet-like carbon-based material mentioned in step one is graphite felt, with dimensions of 15mm × 30mm × 4mm; The carbon fiber reinforced composite material mentioned in step one is a three-dimensional woven C / C composite material with dimensions of 5mm×5mm×10mm; The carbon fiber reinforced composite material mentioned in step one is a pretreated carbon fiber reinforced composite material, and the pretreatment is carried out according to the following steps: the carbon fiber reinforced composite material is polished, and then ultrasonically cleaned with ethanol and deionized water respectively to remove surface impurities; The solder foil mentioned in step two is an AgCuInTi solder with a thickness of 80 micrometers; The base material to be welded in step two is TC4 titanium alloy with dimensions of 10mm×10mm×3mm.

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