Repair powder for damage of high-aluminum high-titanium nickel-based cast superalloy and use method of repair powder

Abstract

The invention discloses repair powder for repairing damaged high-aluminum high-titanium nickel-based cast superalloy after service. The repair powder comprises the following components in parts by mass: 5.0 to 10.0 parts of Cr, 6.0 to 12.0 parts of Co, 2.5 to 10.0 parts of W, 1.0 to 5.0 parts of Mo, 5.0 to 6.5 parts of Al, 0 to 1.5 parts of Ti, 10.0 to 15.0 parts of Ta, 1.0 to 5.0 parts of Re, 0 to 2.0 parts of Hf and 33 to 69.5 parts of Ni. The method for repairing the damaged part of the high-aluminum high-titanium nickel-based cast superalloy after service by using the repairing powder specifically comprises the following steps: step 1, marking a damaged area; 2, removing a damaged area; 3, laser cladding repairing is carried out; step 4, a destressing process; and fifthly, profile recovery is conducted, specifically, the repaired area is machined in the modes of grinding, polishing and the like, and the three-dimensional profile of the part is recovered. The problem that when existing powder for repairing the high Al + Ti nickel-based cast superalloy is used, the high-temperature mechanical property and the environment use performance of a repaired joint cannot be considered at the same time is solved.

Description

Technical Field

[0001] The invention relates to the field of aircraft engine maintenance, in particular to a high-aluminum high-titanium nickel-based cast high-temperature alloy damage repair powder and a use method thereof. Background Art

[0002] With the rapid development of advanced aero-engine performance, the requirements for high-temperature mechanical properties, corrosion resistance and fatigue performance of parts are becoming more and more stringent, resulting in the increasingly widespread application of high Al+Ti nickel-based casting high-temperature alloys, such as K438, K418B, K492M, K447A, K424, etc. The core application of high Al+Ti nickel-based high-temperature alloys is turbine parts, which have complex casting structures and high processing precision, resulting in relatively low product qualification rate and long production cycle, and at the same time causing the price of new products to remain high.

[0003] Since high Al+Ti nickel-based high-temperature alloys have harsh service conditions and are subjected to various complex mechanical effects, they may suffer damage such as wear, cracks, and ablation. Using new castings to directly replace service parts with minor damage is difficult to meet the application needs of existing aircraft engines and is economically unaffordable. Therefore, repairs are urgently needed.

[0004] The total content of Al and Ti in high Al+Ti nickel-based high-temperature alloys is generally 6~11 wt.%, and its weldability is poor. When the same repair material is used for repair, a low-melting-point γ / γ' eutectic is easily formed at the repair interface, thereby promoting the formation of liquid cracks and possibly extending along the grain boundaries, thereby causing the entire part to fail. If low-content Al and Ti repair materials are used, the formation of hot cracks can be effectively avoided. However, due to the low content of γ' phase-forming elements, it is difficult to precipitate a phase with a similar γ' content to the matrix, resulting in a significant reduction in the high-temperature resistance of the repair area, making it difficult to meet the life requirements of an aircraft engine for one service period. In addition, there are large differences in the damage of parts cast with different matrix materials after service, resulting in the need to study different repair materials and methods during repair, which greatly increases the R&D cycle and cost.

[0005] Patent CN 112538583 A discloses a repair material for high Al+Ti equiaxed crystal casting defects. The composition design mainly regulates the content of γ' phase forming elements (Al, Ti, Nb) to ensure that the repair area has excellent high-temperature performance. However, since the high Al+Ti nickel-based high-temperature alloy has excellent oxidation resistance, adding a trace amount of Nb to the repair material may cause the oxidation resistance of the repaired joint to decrease, which cannot meet the service life of the high-temperature alloy.

[0006] Patent CN 113337756 A discloses a Co-based high-temperature alloy repair material with controlled Al element, no Ti element, and optimized Co element content, wherein the Co content is between 40-60 wt.%, belonging to Co-based high-temperature alloy powder. Co-based high-temperature alloy has excellent oxidation resistance and corrosion resistance, but relatively poor high-temperature performance. For some parts, it cannot meet their performance requirements.

[0007] Therefore, it is urgent to develop a repair method that takes into account both the high-temperature mechanical properties and environmental performance of the repaired joint. Summary of the invention

[0008] The purpose of the present invention is to provide a high-aluminum and high-titanium nickel-based cast high-temperature alloy damage repair powder and a method of using the same, so as to solve the problem that the existing high-Al+Ti nickel-based high-temperature alloy repair powder cannot take into account both the high-temperature mechanical properties and environmental performance of the repaired joint when used.

[0009] In order to solve the above technical problems, the present invention adopts the following technical solutions: A repair powder for repairing a high-aluminum, high-titanium nickel-based cast high-temperature alloy after damage after service, comprising the following components in parts by mass: 5.0-10.0 parts of Cr, 6.0-12.0 parts of Co, 2.5-10.0 parts of W, 1.0-5.0 parts of Mo, 5.0-6.5 parts of Al, 0-1.5 parts of Ti, 10.0-15.0 parts of Ta, 1.0-5.0 parts of Re, 0-2.0 parts of Hf, and 33-69.5 parts of Ni.

[0010] In view of the composition characteristics of high Al and high Ti nickel-based cast high-temperature alloys for aircraft engines, in order to ensure that the repaired area has high-temperature resistance similar to or exceeding that of the matrix after repair, a high γ' phase content must be guaranteed, so it is necessary to control the ratio of γ' forming elements. Cast high-temperature alloys with high Al+Ti content are prone to liquid cracks at grain boundaries under the action of laser rapid heating, which leads to part failure; therefore, the present invention proposes a repair powder preparation strategy that maintains Al content, reduces Ti content, and increases Ta content; on the one hand, Ta element, as a γ' phase forming element, can significantly increase the volume fraction of γ' phase, thereby ensuring the high-temperature resistance of the repaired area; on the other hand, a higher Ta / Al ratio will inhibit the segregation between dendrites, thereby ensuring the structural stability of the alloy; in addition, the repair powder proposed by the present invention adds a higher content of Cr, Co, W, Mo and other solid solution strengthening elements, which can ensure that the strength of the alloy is further improved. In order to improve the creep resistance of the repaired area, a small amount of Re is added to the repair powder; therefore, the nickel-based high-temperature alloy repair powder of the above composition of the present invention has a high γ' phase content and ensures that there are no micro cracks at the repair interface, and can be used for damage repair of high Al+Ti cast high-temperature alloys after service. As a further preferred embodiment of the present invention, the following components are included in mass fractions: Cr: 5.2-6.0 parts, Co: 10.0-12.0 parts, W: 6.8-7.2 parts, Mo: 1.0-3.0 parts, Al: 5.5-6.5 parts, Ta: 11.2-14.0 parts, Re: 1.2-3.5 parts, Hf: 1.3-1.5 parts, Ni: 46.3-57.8 parts.

[0011] As a further preference of the present invention, the following components are included in mass proportions: Cr: 6.1-7.3 parts, Co: 8.0-12.0 parts, W: 5.2-5.7 parts, Mo: 1.7-2.2 parts, Al: 5.8-6.4 parts, Ta: 10.0-12.2 parts, Re: 1.5-3.2 parts, Hf: 1.2-1.5 parts, Ni: 49.5-60.5 parts.

[0012] The method for repairing the damaged parts of the high-aluminum, high-titanium nickel-based cast high-temperature alloy after service using any one of the repair powders described above is repaired by laser cladding method, specifically comprising the following steps: Step 1: Mark the damaged area: Use non-destructive testing methods to determine the type and size of the damaged area; Step 2: Remove the damaged area: Use a pneumatic polishing pen to polish the damaged area until the interface presents a metallic luster; then use alcohol to clean the polished surface and perform ultrasonic cleaning to obtain a clean area to be repaired; Step 3: Laser cladding repair: The laser cladding repair method is used to repair the repair area. The process parameters are: laser power: 300-500 W, laser scanning speed: 3-6 mm / s, powder feeding rate: 0.3-0.6 r / min, shielding gas flow: 10-15 L / min, powder feeding gas flow: 5-10 L / min; Step 4: Stress relief process: Use heat treatment to remove residual stress after welding, reduce the strength of the surface after welding, and improve plasticity; Step 5: Surface restoration: Use grinding, polishing and other methods to process the repair area and restore the three-dimensional surface of the part.

[0013] As a further preferred embodiment of the present invention, the nondestructive testing method in step 1 mainly utilizes fluorescent flaw detection and X-ray to check the location and size of damage to parts after service.

[0014] As a further preferred embodiment of the present invention, the particle size of the powder used for repairing in step three is Φ53-Φ150 μm.

[0015] As a further preference of the present invention, the process parameters for the first to second layers in step three are: laser power: 400-500 W, laser scanning speed: 3-4 mm / s, powder feeding rate: 0.3-0.5 r / min, shielding gas flow rate: 10-15 L / min, powder feeding gas flow rate: 5-10 L / min; the process parameters for the third layer and above are: laser power: 300-400 W, laser scanning speed: 33-4 mm / s, powder feeding rate: 0.3-0.5 r / min, shielding gas flow rate: 10-15 L / min, powder feeding gas flow rate: 5-10 L / min.

[0016] Since the repair powder contains a high content of refractory element Ta, in the laser cladding repair process provided by the present invention, a higher laser power is used in the first and second layers to ensure that the powder and the substrate are melted at the same time, so that the defects caused by insufficient melting of the powder are significantly reduced; in the third layer and above, since the substrate has been fully preheated during the repair of the first three layers, the laser power is reduced. Through the above strategy, it is ensured that the cast high-temperature alloy repaired within the energy input range described in the present invention is crack-free and has very excellent high-temperature performance.

[0017] As a further preferred embodiment of the present invention, the specific parameters in the stress relief process in step 4 are: temperature range: 800-1050°C; heat preservation for 2-4 hours; and then natural cooling to 200°C.

[0018] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects: 1. In view of the composition characteristics of high Al+Ti nickel-based cast high-temperature alloys for aircraft engines, in order to ensure that the repaired area has high-temperature resistance similar to or exceeding that of the matrix after repair, a high γ' phase content must be guaranteed, so it is necessary to control the ratio of γ' forming elements. Cast high-temperature alloys with high Al+Ti content are prone to produce liquefaction cracks at grain boundaries under the action of laser rapid heating, which leads to part failure. Therefore, the present invention proposes a repair powder preparation strategy that maintains the Al content, reduces the Ti content, and increases the Ta content; on the one hand, the Ta element, as a forming element of the γ' phase, can significantly increase the volume fraction of the γ' phase, thereby ensuring the high-temperature resistance of the repair area; on the other hand, a higher Ta / Al ratio will inhibit the segregation between dendrites, thereby ensuring the structural stability of the alloy.

[0019] 2. Since the repair powder contains a high content of refractory element Ta, in the laser cladding repair process provided by the present invention, a higher laser power is used in the first and second layers to ensure that the powder and the substrate are melted at the same time, so that the defects caused by insufficient melting of the powder are significantly reduced; in the third layer and above, since the substrate has been fully preheated during the repair of the first three layers, the laser power is reduced. Through the above strategy, it is ensured that the cast high-temperature alloy repaired within the energy input range described in the present invention is crack-free and has very good high-temperature performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a metallographic diagram of K418B high-temperature alloy repaired by laser cladding using the repair-specific powder prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0024] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features of the embodiments may be combined with each other.

[0026] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0027] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or the positions or positional relationships in which the product of the invention is usually placed when in use, or the positions or positional relationships commonly understood by those skilled in the art, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0028] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. Specific embodiment 1: Figure 1 A repair powder for repairing a high-aluminum, high-titanium nickel-based cast high-temperature alloy after service damage is shown, with a particle size of Φ53-Φ150 μm, and mass fractions: Cr: 6.7 parts, Co: 9.0 parts, W: 6.8 parts, Mo: 2.1 parts, Al: 6.2 parts, Ta: 12.2 parts, Hf: 1.3 parts, Re: 2.1 parts, Ni: 53.6 parts. Laser cladding is used to repair the thermal corrosion of the K418B turbine blade tip, and the specific steps are as follows: Step 1: Mark the damaged area: Use visual and X-ray inspection to determine the type and size of the damaged area, which is approximately 1.5 mm × 2.2 mm; Step 2: Remove the damaged area: Use a pneumatic polishing pen to polish the damaged area of ​​the blade tip. The air inlet edge and the blade tip polishing area should be smoothly transitioned until the interface presents a metallic luster; and use alcohol to clean the polished surface and ultrasonically clean it to obtain a clean area to be repaired. The size of the repair area is about 1.8 mm × 2.4 mm; Step 3: Laser cladding repair: Fix the blade on a special tooling, and fix the tooling on a three-jaw chuck; tilt the three-jaw chuck so that the tip of the blade's air inlet edge is perpendicular to the laser head; use the laser cladding repair method to repair the area to be repaired, and the process parameters are: laser power for the first to second layers: 450 W, laser scanning speed: 4 mm / s, powder feeding rate: 0.5 r / min, shielding gas flow: 13 L / min, powder feeding gas flow: 8 L / min; the process parameters for the third layer and above are: laser power: 400 W, laser scanning speed: 4 mm / s, powder feeding rate: 0.5 r / min, shielding gas flow: 13 L / min, powder feeding gas flow: 8 L / min, and the repair path is a reciprocating one; Step 4: Stress relief process: Use heat treatment to remove residual stress at a temperature of 900 °C for 2 hours, then naturally cool to 200 °C before taking out; Step 5: Surface restoration: Use grinding, polishing and other methods to process the repair area to restore the three-dimensional surface of the blade tip; and use three-coordinate detection to ensure that the blade tip meets the design input; Step 6: Nondestructive testing: Fluorescent flaw detection and X-ray testing methods are used to inspect the blades. No defects such as cracks and pores are found, which meets the requirements for repairing the turbine blade tips. Laser cladding repair test was carried out on K418B high temperature alloy test plate, metallographic examination ( Figure 1 ) The results show that the repair interface is well bonded and there are no micro cracks in the repair area. Example 2 A repair powder for repairing a high-aluminum, high-titanium nickel-based cast high-temperature alloy after damage after service, with a particle size of Φ53-Φ150 μm, mass fractions: Cr: 7.2 parts, Co: 8.4 parts, W: 5.7 parts, Mo: 2.2 parts, Al: 6.2 parts, Ta: 13.7 parts, Hf: 1.2 parts, Re: 1.5 parts, Ni: 53.9 parts. Laser cladding is used to repair a certain type of engine tail nozzle adjustment plate with a K424 matrix. The specific steps are as follows: Step 1: Mark the damaged area: Use fluorescent flaw detection to determine that the crack depth on the surface of the adjustment plate is 0.7 mm; Step 2: Remove the damaged area: Use a pneumatic grinding pen to grind the crack area on the surface of the adjustment plate, and make a smooth transition between the crack and the substrate; Step 3: Laser cladding repair: Before repair, place the adjustment sheet in a 200 °C oven for 2 h. After taking it out, immediately use the laser cladding repair method to repair the repair area. The process parameters are: laser power: 500 W, laser scanning speed: 4 mm / s, powder feeding rate: 0.5 r / min, protective gas flow: 13 L / min, powder feeding gas flow: 8 L / min; the repair path is cyclic reciprocating; the number of repair layers is set to: 3 layers; Step 4: Stress relief process: Use heat treatment to remove residual stress, the temperature is 800 °C, the holding time is 2 h, and then naturally cool to 200 °C before taking it out; Step 5: Surface restoration: Use grinding, polishing and other methods to process the repair area and restore the surface of the adjustment piece; Step 6: Nondestructive testing: Fluorescent flaw detection and X-ray testing methods were used to inspect the adjustment plate, and no defects such as cracks and pores were found. It meets the requirements for the use of aircraft engine products.

[0030] Comparative Example 1: Repair powder mass parts: Cr: 6.5 parts, Co: 8.9 parts, W: 6.8 parts, Mo: 1.9 parts, Al: 6.2 parts, Ta: 18.4 parts, Hf: 1.3 parts, Re: 2.1 parts, Ni: 47.9 parts.

[0031] Comparative Example 2: Repair powder mass parts: Cr: 6.6 parts, Co: 8.9 parts, W: 6.8 parts, Mo: 1.9 parts, Al: 6.1 parts, Ta: 6.2 parts, Hf: 1.3 parts, Re: 2.1 parts, Ni: 60.1 parts.

[0032] The repair powders of Example 1, Comparative Example 1 and Comparative Example 2 were used for laser cladding repair of K418B high-temperature alloy test plates, and the room temperature tensile properties and high temperature endurance properties of the repaired samples were tested. The results are listed in Table 1.

[0033] Table 1 Mechanical properties test results of repaired powder laser cladding K418B test plates of Example 1, Comparative Example 1 and Comparative Example 2 sample Tensile strength (MPa) Elongation (%) High temperature endurance time (980 ℃, 160 MPa) Example 1 Repair powder 962 12.1 89.6 Comparative Example 1 Repair Powder 990 1.6 1.74 Comparative Example 2 Repair Powder 867 10.8 14.7 It can be found that after laser cladding K418B in Comparative Example 1, although its room temperature tensile strength is higher than that of the repaired powder in Example 1, its elongation and high temperature endurance performance are extremely low, which is mainly because the Ta content can reduce the solubility of Al in the γ phase, promote the precipitation of the γ' phase, and improve the tensile strength of the repaired sample, while excessive Ta reduces the crack propagation resistance of the high-temperature alloy, resulting in a significant decrease in its elongation and high temperature endurance performance. Compared with Example 1, the Ta content in Comparative Example 2 is significantly reduced, and its room temperature tensile strength is significantly reduced, which is mainly due to the high content of the γ / γ' low melting point eutectic phase, which becomes the source of crack propagation and significantly reduces the tensile strength of the repaired sample.

[0034] Comparative Example 3: The repair powder in Example 1 was used to carry out a laser cladding test on a K418B high-temperature alloy test plate. The process parameters were: laser power: 450 W, laser scanning speed: 4 mm / s, powder feeding rate: 0.5 r / min, shielding gas flow rate: 13 L / min, powder feeding gas flow rate: 8 L / min; the repair path was reciprocating; and the number of layers was set to 20 layers.

[0035] During the cladding process, macro cracks appeared when cladding the 10th layer, and the crack propagation direction was perpendicular to the cladding path. This was mainly due to continuous high-power cladding, which caused the molten pool to maintain an extremely high temperature during cladding, making the temperature gradient of this cladding layer relatively small. However, the temperature gradient between the cladding layer and the cooled cladding layer and the substrate was large. Under the action of thermal stress, cracks initiated and propagated perpendicular to the cladding path. In Example 1, the cladding layers after the third layer reduced laser cladding, reduced heat input, and reduced the temperature gradient between the cladding layer and the substrate, that is, reduced thermal stress, ensuring high-quality laser cladding repair.

[0036] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A repair powder for repairing a high-aluminum, high-titanium nickel-based cast high-temperature alloy after damage after service, characterized in that: The composition includes the following components in parts by mass: Cr: 5.0-10.0 parts, Co: 6.0-12.0 parts, W: 2.5-10.0 parts, Mo: 1.0-5.0 parts, Al: 5.0-6.5 parts, Ti: 0-1.5 parts, Ta: 10.0-15.0 parts, Re: 1.0-5.0 parts, Hf: 0-2.0 parts, Ni: 33-69.5 parts.

2. The repair powder for repairing the high-aluminum and high-titanium nickel-based cast high-temperature alloy after damage after service according to claim 1 is characterized in that: The components are included in the following mass parts: Cr: 5.2-6.0 parts, Co: 10.0-12.0 parts, W: 6.8-7.2 parts, Mo: 1.0-3.0 parts, Al: 5.5-6.5 parts, Ta: 11.2-14.0 parts, Re: 1.2-3.5 parts, Hf: 1.3-1.5 parts, Ni: 46.3-57.8 parts.

3. The repair powder for repairing the high-aluminum and high-titanium nickel-based cast high-temperature alloy after damage after service according to claim 1 is characterized in that: The composition includes the following components in parts by mass: Cr: 6.1-7.3 parts, Co: 8.0-12.0 parts, W: 5.2-5.7 parts, Mo: 1.7-2.2 parts, Al: 5.8-6.4 parts, Ta: 10.0-12.2 parts, Re: 1.5-3.2 parts, Hf: 1.2-1.5 parts, Ni: 49.5-60.5 parts.

4. A method for repairing damage to high-aluminum, high-titanium nickel-based cast high-temperature alloy after service, characterized in that: The method for repairing the damaged parts of the high-aluminum and high-titanium nickel-based cast high-temperature alloy after service using the repair powder according to any one of claims 1 to 3 is repaired by laser cladding method, specifically comprising the following steps: Step 1: Mark the damaged area: Use non-destructive testing methods to determine the type and size of the damaged area; Step 2: Remove the damaged area: Use a pneumatic polishing pen to polish the damaged area until the interface presents a metallic luster; then use alcohol to clean the polished surface and perform ultrasonic cleaning to obtain a clean area to be repaired; Step 3: Laser cladding repair: The laser cladding repair method is used to repair the repair area. The process parameters are: laser power: 300-500 W, laser scanning speed: 3-6 mm / s, powder feeding rate: 0.3-0.6 r / min, shielding gas flow: 10-15 L / min, powder feeding gas flow: 5-10 L / min; Step 4: Stress relief process: Use heat treatment to remove residual stress after welding, reduce the strength of the surface after welding, and improve plasticity; Step 5: Surface restoration: Use grinding, polishing and other methods to process the repair area and restore the three-dimensional surface of the part.

5. The method for repairing damage of high-aluminum and high-titanium nickel-based cast high-temperature alloy after service according to claim 4, characterized in that: The non-destructive testing method in step 1 mainly utilizes fluorescent flaw detection and X-ray to check the location and size of damage to parts after service.

6. The method for repairing damage of high-aluminum and high-titanium nickel-based cast high-temperature alloy after service according to claim 4, characterized in that: The particle size of the powder used for repair in step three is Φ53-Φ150 μm.

7. The method for repairing damage of high-aluminum and high-titanium nickel-based cast high-temperature alloy after service according to claim 4, characterized in that: The process parameters for the first and second layers in the step three are: laser power: 400-500 W, laser scanning speed: 3-4 mm / s, powder feeding rate: 0.3-0.5 r / min, shielding gas flow rate: 10-15 L / min, powder feeding gas flow rate: 5-10 L / min; the process parameters for the third layer and above are: laser power: 300-400 W, laser scanning speed: 3-4 mm / s, powder feeding rate: 0.3-0.5 r / min, shielding gas flow rate: 10-15 L / min, powder feeding gas flow rate: 5-10 L / min.

8. The method for repairing damage of high-aluminum and high-titanium nickel-based cast high-temperature alloy after service according to claim 4, characterized in that: The specific parameters of the stress relief process in step 4 are: temperature range: 800-1050°C; keeping warm for 2-4 hours; and then naturally cooling to 200°C.

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