A high-temperature copper alloy for the inner lining of a rocket engine combustion chamber

Abstract

The present invention discloses a high-temperature copper alloy for a rocket engine combustion chamber liner. The high-temperature copper alloy is composed of a three-dimensional space structure formed by reinforcing ribs and a copper-based alloy that forms a surface layer by wrapping around the outside of the three-dimensional space structure. The preparation method of the high-temperature copper alloy is as follows: S1. Weld three circular-ring-shaped reinforcing ribs and eight round-bar-shaped reinforcing ribs into the three-dimensional space structure; S2. Coat the surface of the reinforcing ribs in the three-dimensional space structure; S3. Place the coated reinforcing ribs obtained in step S2 into a casting mold, use molten copper-based alloy as the casting material, and cast the reinforcing ribs under a protective atmosphere; S4. Cool the copper-based alloy cast in step S3 in the furnace. After cooling to 495-505 °C and holding for 1.5-2.5 h, continue to cool in the furnace until it is cooled to room temperature and then taken out for machining to obtain the high-temperature copper alloy. The high-temperature strength and service temperature of the high-temperature copper alloy prepared by the present invention are significantly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of alloy linings, and specifically relates to a high-temperature copper alloy for the inner lining of a rocket engine combustion chamber. Background Art

[0002] Liquid hydrogen and liquid oxygen engines, as power components of launch vehicles, are being widely used. The inner wall of the combustion chamber of this type of liquid rocket engine is subjected to high temperature, high pressure, and high-speed gas flow, and bears high thermal stress caused by pressure loads and temperature gradients on both sides of the inner wall. The engine combustion chamber is the core component to ensure the normal operation of the rocket, and the working conditions are extremely harsh. If the engine overheats during use, it will cause overheating and overburning of the heat-bearing components, resulting in coarsening of the crystal grains in the internal structure of the material or oxidation or melting at the grain boundaries, thereby greatly reducing the plasticity, impact toughness, fatigue performance, fracture toughness, and corrosion resistance of the material, and causing ablation, cracking, and fracture failures in the hot end part. Therefore, it is particularly important to improve the high-temperature strength of the inner lining material of the combustion chamber.

[0003] Copper-based alloys and copper-based composites can be used as the inner lining material for liquid rocket engine components because they have higher thermal conductivity than other engineering materials. The inner side of the combustion chamber is exposed to the gas, with a temperature as high as several thousand degrees, and a huge heat flow needs to be conducted out through the inner wall of the combustion chamber.

[0004] Using high-thermal-conductivity materials is an effective way to significantly reduce the inner wall temperature and its gradient and improve the service life. However, although pure copper has high thermal conductivity, its strength is not high, especially its low high-temperature strength limits its use.

[0005] Therefore, the present invention prepares a high-temperature copper alloy for good use in the inner lining of a rocket engine combustion chamber. Summary of the Invention

[0006] To solve the above technical problems, the present invention provides a high-temperature copper alloy for the inner lining of a rocket engine combustion chamber.

[0007] The technical solution of the present invention is: a high-temperature copper alloy for the inner lining of a rocket engine combustion chamber, the high-temperature copper alloy is composed of a three-dimensional space structure formed by reinforcing ribs and a copper-based alloy forming a surface layer wrapped outside the three-dimensional space structure, and the three-dimensional space structure is a three-dimensional space structure with an upper hollow cylinder and a lower hollow frustum formed by welding three circular ring-shaped reinforcing ribs and eight circular rod-shaped reinforcing ribs;

[0008] The preparation method of the high-temperature copper alloy is as follows:

[0009] S1. Weld three circular ring-shaped reinforcing ribs and eight circular rod-shaped reinforcing ribs into the three-dimensional space structure;

[0010] S2. Coat a coating on the surface of the reinforcing rib with a three-dimensional spatial structure obtained in step S1;

[0011] S3. Place the coated reinforcing rib obtained in step S2 into a casting mold, use molten copper-based alloy as the casting material, and cast the three-dimensional spatial structure under a protective atmosphere. The molten copper-based alloy is in a liquid state and the temperature > 1100 °C;

[0012] S4. Cool the copper-based alloy after casting in step S3 in the furnace. After cooling to 495 - 505 °C and holding for 1.5 - 2.5 h, continue to cool in the furnace until it is cooled to room temperature and then taken out for machining to obtain a high-temperature copper alloy.

[0013] Further, the material of the reinforcing rib is any one of nickel-based alloy, cobalt-based alloy, and molybdenum-based alloy.

[0014] Note: Nickel-based alloy can maintain a certain strength at high temperatures, has good anti-deformation properties, is more fatigue-resistant than general alloy materials, and will not oxidize, and has certain plasticity; cobalt-based alloy is a hard alloy that can withstand various types of wear, corrosion, and high-temperature oxidation; molybdenum-based alloy is an alloy with high strength and toughness and high temperature resistance; all three alloys have good strength, good thermal fatigue performance, and good oxidation resistance at high temperatures, and the structure is stable under long-term use, and also has good cold formability and welding performance.

[0015] Further, in step S2, the protective atmosphere is nitrogen with a purity > 99.9%.

[0016] Note: Selecting high-purity nitrogen as the protective atmosphere can prevent the copper-based alloy and the reinforcing rib from oxidizing and decarburizing at high temperatures.

[0017] Further, the coating is any one of ceramic coatings such as titanium nitride, aluminum nitride, and titanium carbide.

[0018] Note: Titanium nitride has a high melting point, high hardness, and good chemical stability. It is a quite stable compound and does not react with metals such as iron, chromium, calcium, and magnesium at high temperatures; aluminum nitride is stable at high temperatures in an inert atmosphere, has high thermal conductivity and good electrical insulation performance; titanium carbide has a high melting point, high hardness, and high elastic modulus, good thermal shock resistance and chemical stability; the three materials have high melting points, are good heat shock-resistant materials, and have strong resistance to molten metal erosion.

[0019] Further, in step S2, the method of coating the coating is: Place the reinforcing rib with a three-dimensional spatial structure on the rotating platform in a magnetron sputtering coating machine. The parameters of the magnetron sputtering coating machine are: the number of targets is 2, and the vacuum degree is 0.5 - 1.5×10 -4pa, the platform rotation speed is 0.4 - 0.6 r / min, the single target power is 1.5 - 2.5 kW, the preparation time is 0.2 - 0.8 h, and a coating with a thickness of 1 - 3 μm is deposited.

[0020] Note: The magnitude of the vacuum degree will affect the gas field disturbance and air pressure in a relatively large range of air leakage points; when the sputtering power is too low, the deposition rate is low, and the energy of sputtered atoms reaching the substrate is also low; when the sputtering power is too high, the deposition speed is too fast, affecting the film formation quality and damaging the target; the platform rotation speed will affect the thickness of the deposited film layer.

[0021] Further, the cross-sectional diameter of the circular ring-shaped reinforcing rib and the diameter of the round bar-shaped reinforcing rib are both 2 - 10 mm.

[0022] Note: The diameter of the reinforcing rib is adjusted according to the size of the combustion chamber liner.

[0023] Further, in step S4, the machining methods include turning, milling, and planing.

[0024] Note: Machining does not require mold opening and has a high degree of freedom; moreover, the machining accuracy is very high, which is beneficial to improving the quality of workpieces; turning can complete various surface machining in one clamping; milling has strong adaptability and good flexibility for machining parts; planing has good versatility and can machine vertical and horizontal planes, as well as T-grooves, V-grooves, dovetail grooves, etc.

[0025] Further, after step S4, surface strengthening of the cast copper-based alloy is carried out, including the following steps:

[0026] Raise the temperature to 1050 - 1100 °C and then forge the cast copper-based alloy. After the forging temperature drops by 80 - 90 °C each time, use supersonic particle bombardment on the surface of the copper-based alloy for 5 - 8 s, keep it warm for 10 - 15 min, and repeat the bombardment 2 - 3 times. The particles are ceramic particles.

[0027] Note: Forging the copper-based alloy at high temperature can improve the fatigue strength of the copper-based alloy, and by interspersing supersonic particle bombardment during the cooling process of forging to assist in refining the grain structure on the surface of the copper-based alloy and strengthening the surface strength of the copper-based alloy. Ceramic particles have the advantages of being particularly wear-resistant and having stable physical properties. Then, by keeping it warm, the internal temperature of the copper-based alloy is made uniform, so that the high-temperature strength distribution on the surface of the copper-based alloy is uniform.

[0028] Further, the distance of supersonic particle bombardment from the copper-based alloy is 250 - 280 mm, the bombardment speed is 600 - 800 m / s, and the particle size is 30 - 40 μm.

[0029] Description: When performing supersonic particle bombardment with the above parameters, it is necessary to prevent the bombardment from being too severe and damaging the original surface of the copper-based alloy, and avoid the bombardment from being too light to achieve the surface strengthening effect.

[0030] The beneficial effects of the present invention are as follows:

[0031] (1) The high-temperature copper alloy of the present invention uses a copper-based alloy as the base alloy and the reinforcing rib as the reinforcing alloy. The material of the reinforcing rib is selected from high-melting-point and high-strength alloys to form a three-dimensional structure, and the copper-based alloy wraps the reinforcing rib; this significantly improves the high-temperature strength and service temperature of the high-temperature copper alloy, and the copper-based alloy still has good thermal conductivity.

[0032] (2) The high-temperature copper alloy of the present invention is covered with a dense ceramic coating on the surface of the reinforcing rib by using a physical deposition technique. This ceramic coating can isolate the reinforcing rib from the copper-based alloy and prevent contact, thereby effectively avoiding the reaction between the reinforcing rib and the copper-based alloy.

[0033] (3) The preparation method of the high-temperature copper alloy of the present invention uses a casting technique to prepare a high-temperature copper alloy with reinforcing ribs inside. The high-temperature (700 °C) tensile strength of the prepared high-temperature copper alloy can reach more than 150 MPa. Brief Description of the Drawings

[0034] Figure 1 is the front sectional view of the high-temperature copper alloy of the present invention;

[0035] Figure 2 is the structural diagram of the reinforcing rib of the high-temperature copper alloy of the present invention;

[0036] Among them, 1 - reinforcing rib, 11 - circular ring-shaped reinforcing rib, 12 - round bar-shaped reinforcing rib, 2 - copper-based alloy. Specific Embodiments

[0037] The following further describes the present invention in more detail in combination with specific embodiments to better reflect the advantages of the present invention. Embodiment

[0038] A high-temperature copper alloy for the inner lining of a rocket engine combustion chamber, as Figure 1 and 2 shown, the high-temperature copper alloy is composed of a three-dimensional space structure formed by the reinforcing rib 1 and a copper-based alloy 2 that forms a surface layer by wrapping the outside of the three-dimensional space structure. The three-dimensional space structure is a three-dimensional space structure with an upper hollow cylinder and a lower hollow frustum formed by welding three circular ring-shaped reinforcing ribs 11 and eight round bar-shaped reinforcing ribs 12;

[0039] The preparation method of the high-temperature copper alloy is as follows:

[0040] S1. Weld three circular ring-shaped reinforcing ribs 11 and eight round bar-shaped reinforcing ribs 12 intoFigure 2 The three-dimensional spatial structure shown; the materials of the circular reinforcing rib 11 and the rod-shaped reinforcing rib 12 are both Mo-ZrC molybdenum-based alloys, and the cross-sectional diameter of the circular reinforcing rib 11 and the diameter of the rod-shaped reinforcing rib 12 are both 6 mm;

[0041] S2. Then, place the reinforcing rib 1 with a three-dimensional spatial structure on the rotating platform in the magnetron sputtering coating machine. The parameters of the magnetron sputtering coating machine are as follows: the number of target materials is 2, the vacuum degree is 1.0×10 -4 Pa, the platform rotation speed is 0.5 r / min, the single target material power is 2.0 kW, and the preparation time is 0.5 h. A titanium carbide coating with a thickness of 2 μm is deposited;

[0042] S3. Place the reinforcing rib 1 with a titanium carbide coating obtained in step S2 into the casting mold, and use the molten copper-based alloy 2 in a liquid state and at a temperature of 1200 °C as the casting material to cast the three-dimensional spatial structure under a nitrogen protection atmosphere with a purity of 99.99%;

[0043] S4. Cool the copper-based alloy 2 cast in step S3 in the furnace. After cooling to 500 °C and holding for 2.0 h, continue to cool in the furnace until it is cooled to room temperature and then taken out, and then obtain a high-temperature copper alloy with a high-temperature (700 °C) tensile strength of 210 MPa through turning. Example

[0044] The difference between this example and Example 1 is that the preparation material of the reinforcing rib 1 is GH605 cobalt-based alloy, the coating material is aluminum nitride, and the diameters of the circular reinforcing rib 11 and the rod-shaped reinforcing rib 12 are both 2 mm. Example

[0045] The difference between this example and Example 1 is that the preparation material of the reinforcing rib 1 is GH3039 nickel-based alloy, the coating material is titanium nitride, and the diameters of the circular reinforcing rib 11 and the rod-shaped reinforcing rib 12 are both 10 mm. Example

[0046] The difference between this example and Example 1 is that the thickness of the coating is 1 μm and the preparation time is 0.2 h. Example

[0047] The difference between this example and Example 1 is that the thickness of the coating is 3 μm and the preparation time is 0.8 h. Example

[0048] The difference between this example and Example 1 is that the parameters of the magnetron sputtering coating machine are as follows: the number of target materials is 2, the vacuum degree is 0.5×10 -4 Pa, the platform rotation speed is 0.4 r / min, and the single target material power is 1.5 kW. Example

[0049] The difference between this example and Example 1 is that the parameters of the magnetron sputtering coating machine are as follows: the number of target materials is 2, the vacuum degree is 1.5×10 -4 Pa, the platform rotation speed is 0.6 r / min, and the single target material power is 2.5 kW. Example

[0050] The difference between this example and Example 1 is that in step S4, the copper-based alloy 2 is first cooled in the furnace to 495 °C and held for 1.5 h. Example

[0051] The difference between this example and Example 1 is that in step S4, the copper-based alloy 2 is first cooled in the furnace to 505 °C and held for 2.5 h. Example

[0052] The difference between this example and Example 1 is that after step S4, surface strengthening is performed on the cast copper-based alloy 2, including the following steps:

[0053] The temperature is raised to 1080 °C and then the cast copper-based alloy 2 is forged. After the forging temperature is reduced by 85 °C each time, the surface of the copper-based alloy 2 is bombarded with supersonic particles for 6 s and held for 13 min, and the bombardment is repeated 2 times. The particles are ceramic particles;

[0054] The distance of the supersonic particle bombardment from the copper-based alloy 2 is 65 mm, the bombardment speed is 700 m / s, and the particle size is 35 μm. Example

[0055] The difference between this example and Example 10 is that the forging temperature is 1050 °C, the reduction range of the forging temperature is 90 °C, and the holding time is 10 min. Example

[0056] The difference between this example and Example 10 is that the forging temperature is 1100 °C, the reduction range of the forging temperature is 80 °C, and the holding time is 15 min. Example

[0057] The difference between this example and Example 10 is that the distance of the supersonic particle bombardment from the copper-based alloy 2 is 50 mm, the bombardment speed is 600 m / s, and the particle size is 30 μm. Example

[0058] The difference between this example and Example 10 is that the distance of the supersonic particle bombardment from the copper-based alloy 2 is 80 mm, the bombardment speed is 800 m / s, and the particle size is 40 μm. Example

[0059] The difference between this embodiment and Embodiment 10 is that the bombardment time is 5 s and the bombardment is repeated 2 times. Embodiment

[0060] The difference between this embodiment and Embodiment 10 is that the bombardment time is 8 s and the bombardment is repeated 3 times.

[0061] For the high-temperature copper alloys prepared in each embodiment, 5 samples of each embodiment were taken respectively to test the performance of the high-temperature copper alloy. The performance measurement results of the 5 samples of each embodiment were averaged as the performance measurement results of this embodiment. The specific exploration is as follows:

[0062] 1. Explore the influence of the material parameters of the high-temperature copper alloy and the coating on the high-temperature (700 °C) tensile strength of the high-temperature copper alloy.

[0063] Taking Embodiments 1-5 as experimental comparisons, the results are shown in Table 1:

[0064] Table 1 Influence of Embodiments on the High-Temperature (700 °C) Tensile Strength of High-Temperature Copper Alloys

[0065] It can be seen from the results in Table 1 that since nickel, cobalt, and molybdenum are all high-temperature alloys, the strength of the high-temperature alloy is: molybdenum > cobalt > nickel, the melting point of titanium carbide > titanium nitride > aluminum nitride. If the coating preparation time is too long, i.e., the thickness is too thick, it may not be uniform enough. If the preparation time is too short, i.e., the thickness is too thin, the effect may not be achieved. Therefore, overall, the high-temperature (700 °C) tensile strength of the high-temperature copper alloy prepared from the materials selected in Embodiment 1 is relatively better.

[0066] 2. Explore the influence of the parameters of the magnetron sputtering coating machine on the high-temperature (700 °C) tensile strength of the high-temperature copper alloy.

[0067] Taking Embodiments 1, 6-7 as experimental comparisons, the results are shown in Table 2:

[0068] Table 2 Influence of Embodiments on the High-Temperature (700 °C) Tensile Strength of High-Temperature Copper Alloys

[0069] Group Example 1 Example 6 Example 7 Tensile strength at high temperature (700 °C) / MPa 210 174 195

[0070] It can be seen from the results in Table 2 that the magnitude of the vacuum degree will affect the gas field disturbance and air pressure in a relatively large range of air leakage points; when the sputtering power is too low, the deposition rate is low, and the energy of the sputtered atoms reaching the substrate is also low; when the sputtering power is too high, the deposition speed is too fast, affecting the film formation quality and damaging the target; the platform rotation speed will affect the thickness of the deposited film layer. Therefore, overall, the high-temperature (700 °C) tensile strength of the high-temperature copper alloy prepared from the parameters selected in Embodiment 1 is relatively better.

[0071] 3. Explore the influence of the processing parameters in Step S4 on the high-temperature (700 °C) tensile strength of the high-temperature copper alloy.

[0072] Taking Examples 1, 8 - 9 as experimental comparisons, the results are shown in Table 3 as follows:

[0073] Table 3 Influence of Examples on the Tensile Strength of High - Temperature Copper Alloy at High Temperature (700 °C)

[0074] Group Example 1 Example 8 Example 9 Tensile strength at high temperature (700 °C) / MPa 210 188 219

[0075] It can be seen from the results in Table 3 that the high - temperature (700 °C) tensile strength of Example 9 is higher than that of Example 1. However, Example 9 requires a higher temperature and a longer holding time, and the improvement amplitude is smaller. Therefore, from the economic perspective, the parameter effect of Example 1 is relatively better.

[0076] 4. Explore the influence of the processing parameters of surface strengthening on the high - temperature (700 °C) tensile strength of high - temperature copper alloy.

[0077] Taking Examples 1, 10 - 16 and Control Example 1 as experimental comparisons, the results are shown in Table 4 as follows:

[0078] Table 4 Influence of Examples and Control Example on the Tensile Strength of High - Temperature Copper Alloy at High Temperature (700 °C)

[0079] Group Example 10 Example 11 Example 12 Example 13 Tensile strength at high temperature (700 °C) / MPa 256 234 242 229 Group Example 14 Example 15 Example 16 Control Example 1 Tensile strength at high temperature (700 °C) / MPa 238 228 237 219

[0080] The difference between Control Example 1 and Example 10 is that the forging temperature remains unchanged, and the temperature is lowered after the supersonic particle bombardment is completed;

[0081] It can be seen from the results in Table 4 that after forging and supersonic particle bombardment, the high - temperature (700 °C) tensile strength of the high - temperature copper alloy in Examples 10 - 16 and Control Example 1 has been significantly improved. However, the improvement effect of Control Example 1 is weakened because the forging temperature does not change according to a specific law.

[0082] Too high or too low forging temperature, too large or too small amplitude of forging temperature reduction, too large or too small parameters of supersonic particle bombardment, and too long or too short bombardment time will all affect the high - temperature (700 °C) tensile strength of high - temperature copper alloy. And from the experimental data in Table 4, the high - temperature (700 °C) tensile strength of the high - temperature copper alloy prepared with the parameters of Example 10 is relatively better.

Claims

1. A high-temperature copper alloy for a rocket engine combustion chamber liner, characterized in that, The high-temperature copper alloy is composed of a three-dimensional space structure formed by reinforcing ribs (1) and a copper-based alloy (2) that forms a surface layer by wrapping around the outside of the three-dimensional space structure. The three-dimensional space structure is a three-dimensional space structure with a hollow cylinder at the upper part and a hollow frustum at the lower part, which is formed by welding three circular-ring-shaped reinforcing ribs (11) and eight circular-rod-shaped reinforcing ribs (12). The preparation method of the high-temperature copper alloy is as follows: S1. Weld three circular-ring-shaped reinforcing ribs (11) and eight circular-rod-shaped reinforcing ribs (12) into the three-dimensional space structure; S2. Coat a coating on the surface of the reinforcing rib (1) with a three-dimensional spatial structure obtained in step S1; the method of coating the coating is: place the reinforcing rib (1) with a three-dimensional spatial structure on the rotating platform in a magnetron sputtering coating machine, and the parameters of the magnetron sputtering coating machine are: the number of target materials is 2, the vacuum degree is 0.5~1.5×10 -4 Pa, the platform rotation speed is 0.4~0.6 r / min, the single target material power is 1.5~2.5 kW, the preparation time is 0.2~0.8 h, and a coating with a thickness of 1~3 μm is deposited; S3. Put the coated reinforcing ribs (1) obtained in step S2 into a casting mold, use the molten copper-based alloy (2) as the casting material, and cast the three-dimensional space structure under a protective atmosphere. The molten copper-based alloy (2) is in a liquid state and the temperature > 1100 °C; S4. Cool the copper-based alloy (2) cast in step S3 in the furnace. After cooling to 495 - 505 °C and holding for 1.5 - 2.5 h, continue to cool in the furnace until it is cooled to room temperature and then taken out for machining to obtain the high-temperature copper alloy; After step S4, surface strengthening is carried out on the cast copper-based alloy (2), including the following steps: Raise the temperature to 1050 - 1100 °C and then forge the cast copper-based alloy (2). After the forging temperature drops by 80 - 90 °C each time, use supersonic particle bombardment on the surface of the copper-based alloy (2) for 5 - 8 s, hold for 10 - 15 min, and repeat the bombardment 2 - 3 times. The particles are ceramic particles.

2. The high-temperature copper alloy for the inner lining of a rocket engine combustion chamber according to claim 1, characterized in that, The material of the reinforcing ribs (1) is any one of nickel-based alloys, cobalt-based alloys, and molybdenum-based alloys.

3. The high-temperature copper alloy for the inner lining of a rocket engine combustion chamber according to claim 1, characterized in that, In step S3, the protective atmosphere is nitrogen with a purity > 99.9%.

4. The high-temperature copper alloy for the inner lining of a rocket engine combustion chamber according to claim 1, characterized in that, The coating is any one of ceramic coatings such as titanium nitride, aluminum nitride, and titanium carbide.

5. The high-temperature copper alloy for the inner lining of a rocket engine combustion chamber as described in claim 1, wherein The cross-sectional diameter of the circular-ring-shaped reinforcing ribs (11) and the diameter of the circular-rod-shaped reinforcing ribs (12) are both 2 - 10 mm.

6. The high-temperature copper alloy for the inner lining of a rocket engine combustion chamber according to claim 1, characterized in that, In step S4, the machining methods include turning, milling, and planing.

7. The high-temperature copper alloy for the inner lining of a rocket engine combustion chamber according to claim 1, characterized in that, The distance of supersonic particle bombardment from the copper-based alloy is 250 - 280 mm, the bombardment speed is 600 - 800 m / s, and the particle size is 30 - 40 μm.

Images