Crack repairing method for additive manufacturing nickel-based high-temperature alloy part

Abstract

The invention relates to a crack repairing method for an additive manufacturing nickel-based high-temperature alloy part, and relates to the technical field of high-temperature alloys. According to the main technical scheme, filler powder and solder powder are adopted for conducting crack repairing on the additive manufacturing nickel-based high-temperature alloy part; wherein the solder powder comprises the following chemical components in percentage by weight: 11.0 to 17.0 weight percent of Cr, 5.0 to 9.0 weight percent of W, 1 to 4 weight percent of B, less than or equal to 0.06 weight percent of C, less than or equal to 0.1 weight percent of Co and the balance of Ni; wherein the filler comprises the following chemical components in percentage by weight: 6 to 10 weight percent of Cr, 6 to 10 weight percent of Co, 6 to 10 weight percent of W, 0.5 to 3 weight percent of Mo, 3 to 6 weight percent of Al, 0.5 to 2 weight percent of Ti, 3 to 6 weight percent of Ta, less than or equal to 0.2 weight percent of C, less than or equal to 0.1 weight percent of B, less than or equal to 2 weight percent of Hf and the balance of Ni; the additive manufacturing nickel-based superalloy comprises the following chemical components in percentage by weight: 6 to 10 percent of Cr, 6 to 10 percent of Co, 6 to 10 percent of W, 0.5 to 3 percent of Mo, 3 to 6 percent of Al, 0.5 to 2 percent of Ti, 3 to 6 percent of Ta, less than or equal to 0.2 percent of C, less than or equal to 0.1 percent of B, less than or equal to 2 percent of Hf and the balance of Ni. The method is mainly used for solving the problem of repairing and remanufacturing the cracks of the additive manufacturing nickel-based superalloy part, and has important application value.

Description

Technical Field

[0001] The present invention relates to the technical field of high-temperature alloys, and further to a welding material product for repairing cracks in high-temperature alloy parts, and a crack repair method, and in particular to a crack repair method for additively manufactured nickel-based high-temperature alloy parts. Background Art

[0002] Additive manufacturing high-temperature alloy is a high-temperature alloy prepared by high-temperature alloy powder with the help of laser melting technology or synchronous powder feeding technology. This type of alloy parts has the advantages of short manufacturing cycle and high shape adaptability.

[0003] However, when the content of γ′-forming elements such as Al and Ti in the chemical composition of additively manufactured high-temperature alloys is high, strain aging cracks are very likely to occur during the manufacturing process due to the large amount of precipitation of γ′ precipitate phase in the alloy, which greatly restricts the application of high-temperature alloys with high Al and Ti content bottom strengthening additive manufacturing.

[0004] If the cracks in such parts can be repaired, additive manufacturing of high-temperature alloy crack repair and remanufacturing can be realized, thereby greatly improving the qualified rate of parts production and having broad application prospects. Summary of the invention

[0005] In view of this, the present invention provides a crack repair method for additively manufactured nickel-based high-temperature alloy parts, the main purpose of which is to achieve crack repair of additively manufactured high-temperature alloys.

[0006] In order to achieve the above object, the present invention mainly provides the following technical solutions:

[0007] On the one hand, an embodiment of the present invention provides a method for repairing cracks in an additively manufactured nickel-based high-temperature alloy part, wherein filler powder and solder powder are used to repair cracks in the additively manufactured nickel-based high-temperature alloy part;

[0008] Wherein, the chemical composition of the solder powder includes, by weight percentage: Cr 11.0-17.0wt%, W 5.0-9.0wt%, B 1-4wt%, C≤0.06wt%, Co≤0.1wt%, and Ni as the balance;

[0009] Wherein, the chemical composition of the filler is as follows, in terms of weight percentage: Cr 6-10wt%, Co 6-10wt%, W 6-10wt%, Mo 0.5-3wt%, Al 3-6wt%, Ti 0.5-2wt%, Ta3-6wt%, C≤0.2wt%, B≤0.1wt%, Hf≤2wt%, and Ni is the balance;

[0010] Among them, the chemical composition of the additively manufactured nickel-based high-temperature alloy is as follows, measured in weight percentage: Cr 6-10wt%, Co 6-10wt%, W 6-10wt%, Mo 0.5-3wt%, Al 3-6wt%, Ti 0.5-2wt%, Ta 3-6wt%, C≤0.2wt%, B≤0.1wt%, Hf≤2wt%, and Ni is the balance.

[0011] Preferably, in the solder powder: the content of B is 2 to 3.5 wt%; and / or the filler powder has the same chemical composition as the additively manufactured nickel-based high-temperature alloy part; and / or the solder powder is spherical and / or nearly spherical, with a particle size of -325 mesh; and / or the filler powder is spherical and / or nearly spherical, with a particle size of -140 to +325 mesh.

[0012] Preferably, the preparation of the solder powder comprises:

[0013] Atomizing the solder alloy to obtain alloy powder; sieving the alloy powder to select alloy powder with a set particle size as solder powder;

[0014] Preferably, the parameters of the gas atomization treatment are as follows: the melting temperature is 1390-1590° C.; the powder spraying temperature is 1410-1570° C.; the atomizing gas is an inert gas, preferably argon; and the atomizing pressure is 2-10 MPa.

[0015] Preferably, the preparation of the filler powder comprises:

[0016] Performing a gas atomization treatment on the filler alloy to obtain alloy powder; performing a sieving treatment on the alloy powder, and selecting alloy powder with a set particle size as filler powder;

[0017] Preferably, the parameters of the gas atomization treatment are as follows: the melting temperature is 1450-1620° C.; the powder spraying temperature is 1440-1590° C.; the atomizing gas is an inert gas, preferably argon; and the atomizing pressure is 2-10 MPa.

[0018] Preferably, the crack repair method of the additively manufactured nickel-based high-temperature alloy part comprises the following steps:

[0019] Step S1: Pressing a first paste into a crack of an additively manufactured nickel-based high-temperature alloy part; wherein the first paste comprises filler powder, solder powder and an adhesive;

[0020] Step S2: applying a second paste to the crack to cover the first paste, and to an area near the crack; wherein the second paste comprises solder powder and an adhesive;

[0021] Step S3: applying a flow-blocking agent around the second paste material on the additively manufactured nickel-based high-temperature alloy part;

[0022] Step S4: drying and crack repairing the additively manufactured nickel-based high-temperature alloy part coated with the flow-blocking agent to obtain the additively manufactured high-temperature alloy part after crack repair.

[0023] Preferably, in the first paste, the content of the adhesive shall not exceed 8wt%; preferably, the adhesive is a water-based adhesive; and / or in the first paste, the mass of the solder powder accounts for 40-50wt% of the sum of the mass of the solder powder and the filler powder; and / or the preparation steps of the first paste include: mixing the filler powder with the solder powder to obtain a mixed powder; then adding the adhesive to the mixed powder and stirring to form a first paste; and / or in the second paste, the content of the binder is 8-14wt%.

[0024] Preferably, before step S1, step S0 is also included: removing the oxide layer at the crack to be repaired on the additively manufactured nickel-based high-temperature alloy part; and / or after step S4, step S5 is also included: grinding the residual solder on the additively manufactured high-temperature alloy part after the crack is repaired.

[0025] Preferably, in the step S1: the first paste is pressed into the crack of the additively manufactured nickel-based high-temperature alloy part, and after compaction, the first paste that overflows from the crack to the non-to-be-welded part needs to be cleaned up; and / or in the step S2: the area near the crack refers to: an area that is no more than 2 mm away from the crack; and / or in the step S2, the coating amount of the second paste is not less than 2 times the crack volume; and / or in the step S3, the distance between the flow barrier and the second paste is no more than 2 mm.

[0026] Preferably, in step S4: the drying temperature is 80-150°C, and the drying time is 1-3 hours; and / or after the drying, the surface solder on the additively manufactured nickel-based high-temperature alloy part needs to be trimmed; and / or the crack repair process is performed in a vacuum heat treatment furnace or a vacuum brazing furnace; preferably, the crack repair process is performed at a temperature of 1150-1240°C, and the holding time is 10-30 minutes. Preferably, after the holding time is over, the furnace is cooled or filled with argon for cooling; preferably, before the cooling process, the vacuum pressure in the furnace is not higher than 4×10 -2 Pa.

[0027] Preferably, the crack repair method for additively manufactured nickel-based high-temperature alloy parts is used to repair cracks with a crack gap size not greater than 1.2 mm; and / or the cracks in the additively manufactured high-temperature alloy parts after the crack repair are eliminated, and there are no unwelded defects in the repaired parts.

[0028] Compared with the prior art, the crack repair method of the additively manufactured nickel-based high-temperature alloy part of the present invention has at least the following beneficial effects:

[0029] The embodiment of the present invention provides a crack repair method for additively manufactured nickel-based high-temperature alloy parts, in order to solve the crack repair problem of γ′-strengthened additively manufactured nickel-based high-temperature alloy parts with high Al and Ti. The embodiment of the present invention adopts a method of combining filler powder and solder powder for crack repair. Specifically, powder of the alloy body component is used as filler powder. In order to improve the internal repair density of large gap cracks, a certain amount of low-melting-point and high-wettability solder powder is mixed in the filler. Combined with tight compaction, it is ensured that sufficient powder is preserved in the crack gap to avoid local unwelded defects. In the repair process, the mixed powder (filler powder and solder powder) of the present invention is used as the matrix skeleton in the joint. Compared with directly using filler powder as the skeleton, or adding only a small amount of solder powder as the mixed powder skeleton, it can avoid the situation where the center part is not welded when the repaired crack gap is wide. In addition, since the substrate is a high Al and Ti precipitation-strengthened additive manufacturing high-temperature alloy, even after heat treatment, there is still a large residual internal stress. In this embodiment of the present invention, filler powder with the same composition as the additive manufacturing high-temperature alloy part is used to maximize the matching of the welding material and the substrate, avoiding further stress cracking. In addition, the Cr element and W element, which are also present in the parent material, are added to the chemical composition of the solder powder as strengthening elements to improve the matching. Among them, the amount of Cr element added is more to obtain a better antioxidant effect, and the amount of W element added is moderate to prevent excessive W from causing fluidity to decrease, thereby reducing welding processability. In addition, by limiting the Co element content, crack sensitivity can be reduced. The B element in the solder powder plays a role in lowering the melting point of the solder. The B element is added together with the matrix element Ni and the strengthening elements Cr and W to ensure that the weld improves the solder wettability, fluidity and filling properties while ensuring strength and structural stability, thereby reducing weld defects and improving weld strength.

[0030] Furthermore, in the embodiment of the present invention, when the filler powder, solder powder and adhesive are mixed to form the first paste for pressing into the crack, the amount of adhesive needs to be strictly controlled. If the adhesive is excessive, the density of the weld will be poor, welding defects will occur, and the crack will not be successfully repaired. If the adhesive content is insufficient, the solder paste will have poor fluidity and solidify too quickly, making it difficult to press into the crack.

[0031] Furthermore, in the embodiment of the present invention, different particle sizes are used in the selection of the particle size specifications of the solder and filler powders. The solder powder is finer, while the filler powder is coarser, so that the solder powder can fill the gaps between the filler powders, making full use of the existing space to further achieve a greater space utilization rate, so that more powder can be filled into the cracks. In addition, the use of powders of different particle sizes also increases the actual amount of powder added into the cracks, further ensuring the repair ability of wide gap cracks.

[0032] Furthermore, in the crack repair method for additively manufactured nickel-based high-temperature alloy parts provided by the embodiment of the present invention, after pressing the first paste into the crack, a low-melting-point and high-wettability solder powder (the solder powder is mixed with an adhesive to form a second paste) is directly placed outside the crack, and the excellent flow and gap-filling properties of the solder during the repair process are fully utilized to infiltrate the micro-gap channels in the crack and fill the entire crack. The solder remaining outside the crack can provide a better surface quality than the first paste after post-welding polishing. In summary, the solder powder (second paste) applied to the outside of the crack has excellent flowability, wettability, and gap-filling properties, and can assist in infiltrating the remaining gaps in the crack, thereby improving the internal quality of the joint while ensuring the surface quality.

[0033] In summary, the embodiments of the present invention provide a method for repairing cracks in additively manufactured nickel-based high-temperature alloy parts, which uses alloy powder with the same composition as the additively manufactured high-temperature alloy substrate as filler, combined with high-wettability solder, and with the help of a vacuum heat treatment furnace or vacuum brazing furnace with wide adaptability and low cost. While meeting the use requirements of additively manufactured parts, the method of repair and remanufacturing can greatly improve the pass rate and reduce production costs, and has huge economic value and application value.

[0034] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a macroscopic picture of the additively manufactured nickel-based high-temperature alloy part in Example 1 before crack repair.

[0036] Figure 2 This is an X-ray photograph of the crack site of the additively manufactured nickel-based high-temperature alloy part in Example 1 before crack repair.

[0037] Figure 3 This is a macroscopic photograph of the original crack site of the additively manufactured nickel-based high-temperature alloy part after the crack repair in Example 1.

[0038] Figure 4This is a fluorescent photograph of the original crack site of the additively manufactured nickel-based high-temperature alloy part after the crack repair in Example 1.

[0039] Figure 5 This is an X-ray photograph of the original crack site of the additively manufactured nickel-based high-temperature alloy part after the crack repair in Example 1.

[0040] Figure 6 This is a macroscopic picture of the additively manufactured nickel-based high-temperature alloy part in Example 2 before crack repair.

[0041] Figure 7 This is a macroscopic photograph of the original crack site of the additively manufactured nickel-based high-temperature alloy part after the crack was repaired in Example 2.

[0042] Figure 8 This is a fluorescent photograph of the original crack site of the additively manufactured nickel-based high-temperature alloy part after the crack was repaired in Example 2.

[0043] Fig. 9 This is an X-ray photograph of the original crack site of the additively manufactured nickel-based high-temperature alloy part after the crack was repaired in Example 2.

[0044] Fig.10 This is an X-ray photograph of the crack site of the additively manufactured nickel-based high-temperature alloy part in Example 3 before crack repair.

[0045] Fig.11 This is a macroscopic photograph of the original crack site of the additively manufactured nickel-based high-temperature alloy part after the crack was repaired in Example 3.

[0046] Fig.12 This is an X-ray photograph of the original crack site of the additively manufactured nickel-based high-temperature alloy part after the crack was repaired in Example 3.

[0047] Fig.13 This is a fluorescent photograph of the original crack site of the additively manufactured nickel-based high-temperature alloy part after the crack was repaired in Comparative Example 1.

[0048] Fig.14 Fluorescence photo of the original crack site of the additively manufactured nickel-based high-temperature alloy part after crack repair in Comparative Example 2

[0049] Fig.15 This is a macroscopic photo of the original crack site of the additively manufactured nickel-based high-temperature alloy part after the crack was repaired in Comparative Example 3.

[0050] Fig.16 X-ray photo of the original crack site of the additively manufactured nickel-based high-temperature alloy part after the crack was repaired in Comparative Example 4

[0051] Fig.17 X-ray photo of the original crack site of the additively manufactured nickel-based high-temperature alloy part after the crack was repaired in Comparative Example 5 DETAILED DESCRIPTION

[0052] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation methods, structures, features and effects of the present invention application are described in detail below in conjunction with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures, or characteristics in one or more embodiments may be combined in any suitable form.

[0053] The crack repair method of the additively manufactured nickel-based high-temperature alloy part according to the embodiment of the present invention comprises the following steps:

[0054] Step S0: removing the oxide layer at the crack to be repaired of the additively manufactured nickel-based high-temperature alloy part.

[0055] Step S1: Pressing a first paste into a crack of an additively manufactured nickel-based high-temperature alloy part; wherein the first paste comprises filler powder, solder powder and an adhesive.

[0056] In this step, the filler powder and the solder powder are mechanically mixed to form a mixed powder, in which the solder powder accounts for 40-50%. Then, the adhesive is added to the mixed powder and stirred evenly to form a first paste. The amount of adhesive added shall not exceed 8% of the total weight of the mixed powder and the adhesive. Then, the first paste is pressed into the original crack of the additively manufactured nickel-based high-temperature alloy part. After compaction, the first paste that overflows from the non-to-be-welded part outside the crack is cleaned up (it should be noted that the inside of the crack is the part to be welded, and the outside of the crack is the part not to be welded).

[0057] Preferably, the "pressing" method includes: using a syringe or a dispensing machine to inject the first paste into the crack, or directly using a clean dust-free cloth to dip the solder paste and press it in, but is not limited to this, as long as the first paste is pressed into the crack of the additively manufactured nickel-based high-temperature alloy part.

[0058] It should be noted that: since the present invention is used for repairing ultra-large gap cracks, the proportion of solder powder is strictly required. If the proportion of solder powder is too high, the filler skeleton will not be supported enough, and the solder will be easily lost, resulting in a lack of meat in visual inspection. If the proportion of solder powder is too low, the solder filling will be insufficient, and a large number of micropores will be easily generated, resulting in a dense dot display in the fluorescent inspection. Therefore, the present invention controls the proportion of solder powder in the mixed powder to be 40-50%.

[0059] Wherein, the chemical composition of the solder powder includes, by weight percentage: Cr 11.0-17.0wt%, W 5.0-9.0wt%, B 1-4wt%, C≤0.06wt%, Co≤0.1wt%, and Ni as the balance;

[0060] Wherein, the chemical composition of the filler is as follows, in terms of weight percentage: Cr 6-10wt%, Co 6-10wt%, W 6-10wt%, Mo 0.5-3wt%, Al 3-6wt%, Ti 0.5-2wt%, Ta3-6wt%, C≤0.2wt%, B≤0.1wt%, Hf≤2wt%, and Ni is the balance;

[0061] Among them, the chemical composition of the additively manufactured nickel-based high-temperature alloy is as follows, measured in weight percentage: Cr 6-10wt%, Co 6-10wt%, W 6-10wt%, Mo 0.5-3wt%, Al 3-6wt%, Ti 0.5-2wt%, Ta 3-6wt%, C≤0.2wt%, B≤0.1wt%, Hf≤2wt%, and Ni is the balance.

[0062] Preferably, the filler powder has the same chemical composition as the additively manufactured nickel-based high-temperature alloy part.

[0063] Preferably, the solder powder is spherical and / or nearly spherical, and has a particle size of -325 mesh (particles that can pass through a 325 mesh sieve).

[0064] Preferably, the filler powder is spherical and / or nearly spherical, and has a particle size of (-140 to +325) mesh. Here, "-" means "undersize", "+" means "onsize", and -140 to +325 mesh means particles between 140 mesh and 325 mesh.

[0065] Preferably, the solder powder is prepared by gas atomization, and the gas atomization process parameters are: melting temperature is 1390-1590°C, powder spraying temperature is 1410-1570°C, atomizing gas is argon, and atomizing pressure is 2-10MPa; the prepared alloy powder is sieved to obtain an alloy powder with a particle size of -325 mesh, which is the solder powder.

[0066] Preferably, the filler powder is prepared by gas atomization, and the gas atomization process parameters are: melting temperature is 1450-1620°C, powder spraying temperature is 1440-1590°C, atomizing gas is argon, and atomizing pressure is 2-10MPa; the prepared alloy powder is sieved to obtain an alloy powder with a particle size of (-140 to +325), which is the filler powder.

[0067] Step S2: applying a second paste to the crack to cover the first paste, and applying the second paste to an area near the crack; wherein the second paste comprises solder powder and an adhesive.

[0068] Preferably, in this step, an adhesive is added to the solder powder and stirred evenly to form a second paste, the amount of adhesive added is 8% to 14% of the total weight of the solder powder and the adhesive, and then the second paste is applied to the outer surface of the paste mixed solder and within 2 mm of the metal substrate outside the original crack. The total coating amount must not be less than twice the volume of the original crack to ensure that sufficient solder can flow into the skeleton (filler) at high temperature to avoid welding defects caused by insufficient solder.

[0069] Step S3: applying a flow inhibitor around the second paste material on the additively manufactured nickel-based high-temperature alloy part.

[0070] Preferably, in this step, the flow blocker is applied around the solder paste, and the distance between the flow blocker and the second solder paste should not exceed 2 mm.

[0071] Step S4: drying and crack repairing the additively manufactured nickel-based high-temperature alloy part coated with the flow-blocking agent to obtain the additively manufactured high-temperature alloy part after crack repair.

[0072] Preferably, in this step, the additively manufactured nickel-based high-temperature alloy parts are placed in an oven at 80 to 150°C for drying for 1 to 3 hours, and the surface solder (surface paste) is appropriately trimmed; then the parts to be repaired are placed in a vacuum heat treatment furnace or a vacuum brazing furnace for crack repair, wherein the temperature of the crack repair treatment is (1150 to 1240)°C, and the holding time is 10 to 30 minutes. It should be noted here that the selection of the above-mentioned crack repair treatment temperature does not exceed the limit temperature that the alloy can withstand, and will not damage the alloy itself, while ensuring that the melting and filling effects of the brazing material meet the repair requirements. In addition, the holding time is short and the economy is better, and the shorter holding time can reduce the impact on the alloy. Although the time is short, it is sufficient to ensure the full flow and filling of the brazing material. After welding, furnace cooling or argon filling is used for cooling, and the vacuum pressure in the furnace before cooling is not higher than 4×10 -2 Pa to ensure that the parts, fillers and solder are not oxidized, and that the solder has good wettability to the substrate and fillers during the repair process.

[0073] Step S5: grinding the residual solder on the outer metal of the original crack position of the additively manufactured high-temperature alloy part after the crack repair to the prototype surface state of the part.

[0074] The adhesive mentioned in the above steps of this embodiment is a water-based adhesive or an oily adhesive, preferably a water-based adhesive (such as Nicrobraz s-binder adhesive produced by Wall Colmonoy Company).

[0075] By using the above crack repair method of the embodiment of the present invention, cracks with a gap of no more than 1.2 mm in the additively manufactured nickel-based high-temperature alloy parts can be repaired. After the repair, the original cracks are eliminated and there are no unwelded defects in the repaired parts.

[0076] The present invention is further described below in conjunction with preferred embodiments:

[0077] Example 1

[0078] This embodiment provides a crack repair method for additively manufactured nickel-based high-temperature alloy parts, wherein:

[0079] The additively manufactured nickel-based high-temperature alloy part used in this embodiment is a part with a chemical composition of Ni-8Cr-8Co-7.85W-6Ta-5.5Al-0.7Ti-2Mo-0.08C-0.015B printed by selective laser melting technology, see Figure 1 and Figure 2 As shown, there is a through crack on the part, and the gap at the widest point of the crack is 1mm.

[0080] The filler powder used in this embodiment is an alloy powder with the same chemical composition as the parts prepared by gas atomization. The gas atomization process parameters are: melting temperature is 1560℃, powder spraying temperature is 1540℃, atomization gas is argon, and atomization pressure is 9MPa. The alloy powder obtained by atomization is sieved to obtain an alloy powder with a particle size of (-140~+325), which is the filler powder of this embodiment.

[0081] The solder powder used in this embodiment is an alloy powder with a chemical composition of Ni-15Cr-7W-3B prepared by gas atomization. The gas atomization process parameters are: melting temperature of 1510°C, powder spraying temperature of 1490°C, atomization gas of argon, and atomization pressure of 8MPa. The alloy powder obtained by atomization is sieved to obtain an alloy powder with a particle size of -325 mesh, which is the solder powder of this embodiment.

[0082] The crack repair method of this embodiment comprises the following steps:

[0083] Step S0: using sand blasting combined with grinding to remove the oxide layer at the crack to be repaired.

[0084] Step S1: mechanically mix the filler powder and the solder powder in a ratio of 60%:40% to form a mixed powder, then add a water-based adhesive (Nicrobraz s-binder adhesive produced by Wall Colmonoy) to the mixed powder and stir evenly to form a first paste. The amount of the adhesive added is 7wt% of the total weight of the mixed powder and the adhesive. Then, the first paste is pressed into the original crack of the additively manufactured nickel-based high-temperature alloy part with the help of a weighing spoon, and after compaction, the paste mixed solder overflowing from the crack and not to be welded is cleaned up.

[0085] Step S2: Add a water-based adhesive (Nicrobraz s-binder adhesive produced by Wall Colmonoy) to the solder powder and stir evenly to form a second paste. The amount of the adhesive added accounts for 12wt% of the total weight of the solder powder and the adhesive. Then, the second paste is applied to the outer surface of the first paste and within 2mm of the metal substrate outside the original crack, and the total coating amount is 2.5 times the volume of the original crack.

[0086] Step S3: Apply the flow blocker around the second paste, and the maximum distance between the flow blocker and the second paste is 1.5 mm.

[0087] Step S4: Place the additively manufactured nickel-based high-temperature alloy parts that have been coated with the above-mentioned coating in a 110°C oven for drying for 1.5 hours, and slightly trim the unevenly coated areas of the surface solder; then place the additively manufactured nickel-based high-temperature alloy parts in a vacuum heat treatment furnace for crack repair. The temperature for crack repair treatment is 1160°C, and the insulation time is 10 minutes. After the insulation is completed, argon is filled and cooled to below 80°C. The vacuum pressure in the furnace is always no higher than 4×10 - 2 Pa.

[0088] Step S5: After the crack-repaired additively manufactured nickel-based high-temperature alloy part is taken out of the furnace, the residual solder on the outer metal of the original crack position is polished to the prototype surface state of the part.

[0089] in, Figure 3 This is a macroscopic photograph of the original crack site of the additively manufactured nickel-based high-temperature alloy component after the crack is repaired in this embodiment. Fluorescence penetration and X-ray inspection are performed on the original crack site of the additively manufactured nickel-based high-temperature alloy component after the crack is repaired. Figure 4 and Figure 5 As shown. Figure 3-Figure 5 It can be seen that: no defects were found, confirming that the original cracks have been eliminated, there are no unwelded defects, and successful repair has been achieved.

[0090] Example 2

[0091] This embodiment provides a crack repair method for additively manufactured nickel-based high-temperature alloy parts, wherein:

[0092] The additively manufactured nickel-based high-temperature alloy part used in this embodiment is a part with a chemical composition of Ni-8Cr-8Co-8W-6Ta-5.5Al-0.7Ti-2Mo-0.1C-0.015B-1.4Hf printed by selective laser melting technology, see Figure 6 As shown, there is a through crack on the part, and the gap at the widest point of the crack is 1.2mm.

[0093] The filler powder used in this embodiment is an alloy powder with the same chemical composition as the parts prepared by gas atomization. The gas atomization process parameters are: melting temperature is 1560℃, powder spraying temperature is 1540℃, atomization gas is argon, and atomization pressure is 9MPa. The alloy powder obtained by atomization is sieved to obtain an alloy powder with a particle size of (-140~+325), which is the filler powder of this embodiment.

[0094] The solder powder used in this embodiment is an alloy powder with a chemical composition of Ni-16Cr-8W-2.5B prepared by gas atomization. The gas atomization process parameters are: melting temperature of 1540°C, powder spraying temperature of 1520°C, atomization gas of argon, and atomization pressure of 8MPa. The alloy powder obtained by atomization is sieved to obtain an alloy powder with a particle size of -325 mesh, which is the solder powder of this embodiment.

[0095] The crack repair method of this embodiment comprises the following steps:

[0096] Step S0: using sand blasting combined with grinding to remove the oxide layer at the crack to be repaired.

[0097] Step S1: mechanically mix the filler powder and the solder powder in a ratio of 50%:50% to form a mixed powder, and then add a water-based adhesive (Nicrobraz s-binder adhesive produced by Wall Colmonoy) to the mixed powder and stir evenly to form a first paste. The amount of the adhesive added is 6wt% of the total weight of the mixed powder and the adhesive. Then, the first paste is pressed into the original crack of the additively manufactured nickel-based high-temperature alloy part with the help of a weighing spoon, and after compaction, the paste mixed solder overflowing from the crack and not to be welded is cleaned up.

[0098] Step S2: Add a water-based adhesive (Nicrobraz s-binder adhesive produced by Wall Colmonoy) to the solder powder and stir evenly to form a second paste. The amount of the adhesive added accounts for 12wt% of the total weight of the solder powder and the adhesive. Then, the second paste is applied to the outer surface of the first paste and within 2mm of the metal substrate outside the original crack, and the total coating amount is 3 times the volume of the original crack.

[0099] Step S3: Apply the flow blocker around the second paste, and the maximum distance between the flow blocker and the second paste is 1.6 mm.

[0100] Step S4: Place the additively manufactured nickel-based high-temperature alloy parts that have been coated with the above-mentioned coating in a 110°C oven for drying for 1.5 hours, and slightly trim the unevenly coated areas of the surface solder; then place the additively manufactured nickel-based high-temperature alloy parts in a vacuum heat treatment furnace for crack repair. The temperature for crack repair treatment is 1230°C, and the insulation time is 30 minutes. After the insulation is completed, argon is filled and cooled to below 80°C. The vacuum pressure in the furnace is always no higher than 4×10 - 2 Pa.

[0101] Step S5: After the crack-repaired additively manufactured nickel-based high-temperature alloy part is taken out of the furnace, the residual solder on the outer metal of the original crack position is polished to the prototype surface state of the part.

[0102] Figure 7 This is a macroscopic photograph of the original crack site of the additively manufactured nickel-based high-temperature alloy component after the crack is repaired in this embodiment. Fluorescence penetration and X-ray inspection are performed on the original crack site of the additively manufactured nickel-based high-temperature alloy component after the crack is repaired. Figure 8 and Fig. 9 As shown, it can be seen that: no defect display is found, confirming that the original crack has been eliminated, there is no unwelded defect, and successful repair is achieved.

[0103] Example 3

[0104] This embodiment provides a crack repair method for additively manufactured nickel-based high-temperature alloy parts, wherein:

[0105] The additively manufactured nickel-based high-temperature alloy part used in this embodiment is a part with a chemical composition of Ni-7Cr-7.5Co-8W-5Ta-4.5Al-1.1Ti-2.2Mo-0.12C-0.03B printed by selective laser melting technology, see Fig.10 As shown, there is a through crack on the part, and the gap at the widest point of the crack is 1mm.

[0106] The filler powder used in this embodiment is an alloy powder with the same chemical composition as the parts prepared by gas atomization. The gas atomization process parameters are: melting temperature is 1560℃, powder spraying temperature is 1540℃, atomization gas is argon, and atomization pressure is 9MPa. The alloy powder obtained by atomization is sieved to obtain an alloy powder with a particle size of (-140~+325), which is the filler powder of this embodiment.

[0107] The solder powder used in this embodiment is an alloy powder with a chemical composition of Ni-15Cr-5.5W-1.8B prepared by gas atomization. The gas atomization process parameters are: melting temperature of 1545°C, powder spraying temperature of 1520°C, atomization gas of argon, and atomization pressure of 8MPa. The alloy powder obtained by atomization is sieved to obtain an alloy powder with a particle size of -325 mesh, which is the solder powder of this embodiment.

[0108] The crack repair method of this embodiment comprises the following steps:

[0109] Step S0: using sand blasting combined with grinding to remove the oxide layer at the crack to be repaired.

[0110] Step S1: mechanically mix the filler powder and the solder powder in a ratio of 60%:40% to form a mixed powder, then add a water-based adhesive (Nicrobraz s-binder adhesive produced by Wall Colmonoy) to the mixed powder and stir evenly to form a first paste. The amount of the adhesive added is 8wt% of the total weight of the mixed powder and the adhesive. Then, the first paste is pressed into the original crack of the additively manufactured nickel-based high-temperature alloy part with the help of a weighing spoon, and after compaction, the paste mixed solder overflowing from the crack and not to be welded is cleaned up.

[0111] Step S2: Add a water-based adhesive (Nicrobraz s-binder adhesive produced by Wall Colmonoy) to the solder powder and stir evenly to form a second paste. The amount of the adhesive added accounts for 13wt% of the total weight of the solder powder and the adhesive. Then, the second paste is applied to the outer surface of the first paste and within 2mm of the metal substrate outside the original crack, and the total coating amount is 3 times the volume of the original crack.

[0112] Step S3: Apply the flow blocker around the second paste, and the maximum distance between the flow blocker and the second paste is 1.5 mm.

[0113] Step S4: Place the additively manufactured nickel-based high-temperature alloy parts that have been coated with the above-mentioned coating in a 120°C oven for drying for 1.5 hours, and slightly trim the unevenly coated areas on the surface of the solder; then place the additively manufactured nickel-based high-temperature alloy parts in a vacuum heat treatment furnace for crack repair. The temperature for crack repair treatment is 1240°C, and the insulation time is 12 minutes. After the insulation is completed, the furnace is cooled to below 80°C. The vacuum pressure in the furnace is always no higher than 4×10 - 2 Pa.

[0114] Step S5: After the crack-repaired additively manufactured nickel-based high-temperature alloy part is taken out of the furnace, the residual solder on the outer metal of the original crack position is polished to the prototype surface state of the part.

[0115] Fig.11 is a macroscopic photograph of the original crack site of the additively manufactured nickel-based high-temperature alloy part after the crack is repaired in this embodiment. Fig.12 This is an X-ray photo of the original crack position of the additively manufactured nickel-based high-temperature alloy part after the crack is repaired in this embodiment. Fig.11 and Fig.12 It can be seen that: no defects were found, confirming that the original cracks have been eliminated, there are no unwelded defects, and successful repair has been achieved.

[0116] It should be noted here that: compared with Example 3, the B content in the solder of Example 1 and Example 2 is higher. Therefore, the fluidity, wettability and filling properties of the solder in Example 1 and Example 2 are better, which is more helpful to avoid defects and obtain a denser weld structure.

[0117] Comparative Example 1

[0118] Comparative Example 1 provides a method for repairing cracks in additively manufactured nickel-based high-temperature alloy parts, wherein:

[0119] The additively manufactured nickel-based high-temperature alloy part used in this embodiment is a part with a chemical composition of Ni-8Cr-8Co-8W-6Ta-5.5Al-0.7Ti-2Mo-0.1C-0.015B-1.4Hf printed by selective laser melting technology. There is a through crack on the part, and the gap at the widest part of the crack is 1.2 mm.

[0120] The filler powder used in this embodiment is an alloy powder with the same chemical composition as the parts prepared by gas atomization. The gas atomization process parameters are: melting temperature is 1560℃, powder spraying temperature is 1540℃, atomization gas is argon, and atomization pressure is 9MPa. The alloy powder obtained by atomization is sieved to obtain an alloy powder with a particle size of (-140~+325), which is the filler powder of this embodiment.

[0121] The solder powder used in this embodiment is an alloy powder with a chemical composition of Ni-16Cr-8W-2.5B prepared by gas atomization. The gas atomization process parameters are: melting temperature of 1540°C, powder spraying temperature of 1520°C, atomization gas of argon, and atomization pressure of 8MPa. The alloy powder obtained by atomization is sieved to obtain an alloy powder with a particle size of -325 mesh, which is the solder powder of this embodiment.

[0122] The crack repair method of this embodiment comprises the following steps:

[0123] Step S0: using sand blasting combined with grinding to remove the oxide layer at the crack to be repaired.

[0124] Step S1: mechanically mix the filler powder and the solder powder in a ratio of 50%:50% to form a mixed powder, and then add a water-based adhesive (Nicrobraz s-binder adhesive produced by Wall Colmonoy) to the mixed powder and stir evenly to form a first paste. The amount of adhesive added is 10% of the total weight of the mixed powder and the adhesive. Then, the first paste is pressed into the original crack of the additively manufactured nickel-based high-temperature alloy part with the help of a weighing spoon, and after compaction, the paste mixed solder overflowing from the crack and not to be welded is cleaned up.

[0125] Step S2: Add a water-based adhesive (Nicrobraz s-binder adhesive produced by Wall Colmonoy) to the solder powder and stir evenly to form a second paste. The amount of the adhesive added accounts for 12% of the total weight of the solder powder and the adhesive. Then, the second paste is applied to the outer surface of the first paste and within 2 mm of the metal substrate outside the original crack, and the total coating amount is 3 times the volume of the original crack.

[0126] Step S3: Apply the flow blocker around the second paste, and the maximum distance between the flow blocker and the second paste is 1.6 mm.

[0127] Step S4: Place the additively manufactured nickel-based high-temperature alloy parts that have been coated with the above-mentioned coating in a 110°C oven for drying for 1.5 hours, and slightly trim the unevenly coated areas of the surface solder; then place the additively manufactured nickel-based high-temperature alloy parts in a vacuum heat treatment furnace for crack repair. The temperature for crack repair treatment is 1230°C, and the insulation time is 30 minutes. After the insulation is completed, argon is filled and cooled to below 80°C. The vacuum pressure in the furnace is always no higher than 4×10 - 2 Pa.

[0128] Step S5: After the crack-repaired additively manufactured nickel-based high-temperature alloy part is taken out of the furnace, the residual solder on the outer metal of the original crack position is polished to the prototype surface state of the part.

[0129] See also Fig.13 As shown in the figure, the original cracked part of the repaired part was inspected and it was found that the original cracked part showed local dot-like display after fluorescent penetration, indicating that the density of the repaired part was poor and there were local defects of unwelded parts. This is because the content of adhesive in the paste-like mixed solder pressed into the crack exceeded 8%, resulting in poor density of the weld and welding defects, which made the crack fail to be successfully repaired.

[0130] Comparative Example 2

[0131] This embodiment provides a crack repair method for additively manufactured nickel-based high-temperature alloy parts, wherein:

[0132] The additively manufactured nickel-based high-temperature alloy part used in this embodiment is a part with a chemical composition of Ni-8Cr-8Co-8W-6Ta-5.5Al-0.7Ti-2Mo-0.1C-0.015B-1.4Hf printed by selective laser melting technology. There is a through crack on the part, and the gap at the widest part of the crack is 1.2 mm.

[0133] The filler powder used in this embodiment is an alloy powder with the same chemical composition as the parts prepared by gas atomization. The gas atomization process parameters are: melting temperature is 1560℃, powder spraying temperature is 1540℃, atomization gas is argon, and atomization pressure is 9MPa. The alloy powder obtained by atomization is sieved to obtain an alloy powder with a particle size of (-140~+325), which is the filler powder of this embodiment.

[0134] The solder powder used in this embodiment is an alloy powder with a chemical composition of Ni-16Cr-8W-2.5B prepared by gas atomization. The gas atomization process parameters are: melting temperature is 1540°C, powder spraying temperature is 1520°C, atomization gas is argon, and atomization pressure is 8MPa. The alloy powder obtained by atomization is sieved to obtain an alloy powder with a particle size of (-140 to +325), which is the solder powder of this embodiment.

[0135] The crack repair method of this embodiment comprises the following steps:

[0136] Step S0: using sand blasting combined with grinding to remove the oxide layer at the crack to be repaired.

[0137] Step S1: mechanically mix the filler powder and the solder powder in a ratio of 50%:50% to form a mixed powder, then add a water-based adhesive (Nicrobraz s-binder adhesive produced by Wall Colmonoy) to the mixed powder and stir evenly to form a first paste. The amount of adhesive added is 6% of the total weight of the mixed powder and the adhesive. Then, the first paste is pressed into the original crack of the additively manufactured nickel-based high-temperature alloy part with the help of a weighing spoon, and after compaction, the paste mixed solder overflowing from the crack and not to be welded is cleaned up.

[0138] Step S2: Add a water-based adhesive (Nicrobraz s-binder adhesive produced by Wall Colmonoy) to the solder powder and stir evenly to form a second paste. The amount of the adhesive added accounts for 12% of the total weight of the solder powder and the adhesive. Then, the second paste is applied to the outer surface of the first paste and within 2 mm of the metal substrate outside the original crack, and the total coating amount is 3 times the volume of the original crack.

[0139] Step S3: Apply the flow blocker around the second paste, and the maximum distance between the flow blocker and the second paste is 1.6 mm.

[0140] Step S4: Place the additively manufactured nickel-based high-temperature alloy parts that have been coated with the above-mentioned coating in a 110°C oven for drying for 1.5 hours, and slightly trim the unevenly coated areas of the surface solder; then place the additively manufactured nickel-based high-temperature alloy parts in a vacuum heat treatment furnace for crack repair. The temperature for crack repair treatment is 1230°C, and the insulation time is 30 minutes. After the insulation is completed, argon is filled and cooled to below 80°C. The vacuum pressure in the furnace is always no higher than 4×10 - 2 Pa.

[0141] Step S5: After the crack-repaired additively manufactured nickel-based high-temperature alloy part is taken out of the furnace, the residual solder on the outer metal of the original crack position is polished to the prototype surface state of the part.

[0142] like Fig.14 As shown in the figure, the original cracked part of the repaired part was inspected and it was found that the original cracked part showed local linear display after fluorescent penetration, indicating that the density of the repaired part was poor and there were local defects. This was because the particle size of the solder powder was not appropriate, resulting in insufficient space utilization of the mixed solder, which in turn made the total amount of mixed solder pressed into the crack small, resulting in poor density of the weld and welding defects, so that the crack could not be successfully repaired.

[0143] Comparative Example 3

[0144] This comparative example provides a crack repair method for additively manufactured nickel-based high-temperature alloy parts, wherein:

[0145] The additively manufactured nickel-based high-temperature alloy part used in this comparative example is a part with a chemical composition of Ni-8Cr-8Co-7.85W-6Ta-5.5Al-0.7Ti-2Mo-0.08C-0.015B printed by selective laser melting technology, see Figure 1 and Figure 2 As shown, there is a through crack on the part, and the gap at the widest point of the crack is 1mm.

[0146] The filler powder used in this comparative example is an alloy powder with the same chemical composition as the parts prepared by gas atomization. The gas atomization process parameters are: melting temperature is 1560℃, powder spraying temperature is 1540℃, atomization gas is argon, and atomization pressure is 9MPa. The alloy powder obtained by atomization is sieved to obtain an alloy powder with a particle size of (-140~+325), which is the filler powder of this example.

[0147] The solder powder used in this comparative example is an alloy powder with a chemical composition of Ni-15Cr-7W-0.8B prepared by gas atomization. The gas atomization process parameters are: melting temperature of 1550°C, powder spraying temperature of 1530°C, atomization gas of argon, and atomization pressure of 8MPa. The alloy powder obtained by atomization is sieved to obtain an alloy powder with a particle size of -325 mesh, which is the solder powder of this example.

[0148] The crack repairing method of this comparative example comprises the following steps:

[0149] Step S0: using sand blasting combined with grinding to remove the oxide layer at the crack to be repaired.

[0150] Step S1: mechanically mix the filler powder and the solder powder in a ratio of 60%:40% to form a mixed powder, then add a water-based adhesive (Nicrobraz s-binder adhesive produced by Wall Colmonoy) to the mixed powder and stir evenly to form a first paste. The amount of the adhesive added is 7wt% of the total weight of the mixed powder and the adhesive. Then, the first paste is pressed into the original crack of the additively manufactured nickel-based high-temperature alloy part with the help of a weighing spoon, and after compaction, the paste mixed solder overflowing from the crack and not to be welded is cleaned up.

[0151] Step S2: Add a water-based adhesive (Nicrobraz s-binder adhesive produced by Wall Colmonoy) to the solder powder and stir evenly to form a second paste. The amount of the adhesive added accounts for 12wt% of the total weight of the solder powder and the adhesive. Then, the second paste is applied to the outer surface of the first paste and within 2mm of the metal substrate outside the original crack, and the total coating amount is 2.5 times the volume of the original crack.

[0152] Step S3: Apply the flow blocker around the second paste, and the maximum distance between the flow blocker and the second paste is 1.5 mm.

[0153] Step S4: Place the additively manufactured nickel-based high-temperature alloy parts that have been coated with the above-mentioned coating in a 110°C oven for drying for 1.5 hours, and slightly trim the unevenly coated areas of the surface solder; then place the additively manufactured nickel-based high-temperature alloy parts in a vacuum heat treatment furnace for crack repair. The temperature for crack repair treatment is 1240°C, and the insulation time is 15 minutes. After the insulation is completed, argon is filled and cooled to below 80°C. The vacuum pressure in the furnace is always no higher than 4×10 - 2 Pa.

[0154] Step S5: After the crack-repaired additively manufactured nickel-based high-temperature alloy part is taken out of the furnace, the residual solder on the outer metal of the original crack position is polished to the prototype surface state of the part.

[0155] like Fig.15 As shown in the figure, the original crack site of the repaired part was inspected, and visually found that there were some parts of the original crack site that were not welded. This shows that the solder powder used had insufficient fluidity and filling properties, and failed to fully melt and fill the micro gaps between the fillers, resulting in serious lack of bonding strength between the solder, filler and parent material, and visually visible non-welding defects.

[0156] Comparative Example 4

[0157] This comparative example provides a crack repair method for additively manufactured nickel-based high-temperature alloy parts, wherein:

[0158] The additively manufactured nickel-based high-temperature alloy part used in this comparative example is a part with a chemical composition of Ni-8Cr-8Co-8W-6Ta-5.5Al-0.7Ti-2Mo-0.1C-0.015B-1.4Hf printed by selective laser melting technology. There is a through crack on the part, and the gap at the widest point of the crack is 1.2 mm.

[0159] The filler powder used in this comparative example is an alloy powder with the same chemical composition as the parts prepared by gas atomization. The gas atomization process parameters are: melting temperature is 1560°C, powder spraying temperature is 1540°C, atomization gas is argon, and atomization pressure is 9MPa. The alloy powder obtained by atomization is sieved to obtain an alloy powder with a particle size of -325 mesh, which is the filler powder of this example.

[0160] The solder powder used in this comparative example is an alloy powder with a chemical composition of Ni-16Cr-8W-2.5B prepared by gas atomization. The gas atomization process parameters are: melting temperature of 1540°C, powder spraying temperature of 1520°C, atomization gas of argon, and atomization pressure of 8MPa. The alloy powder obtained by atomization is sieved to obtain an alloy powder with a particle size of -325 mesh, which is the solder powder of this example.

[0161] The crack repairing method of this comparative example comprises the following steps:

[0162] Step S0: using sand blasting combined with grinding to remove the oxide layer at the crack to be repaired.

[0163] Step S1: mechanically mix the filler powder and the solder powder in a ratio of 50%:50% to form a mixed powder, and then add a water-based adhesive (Nicrobraz s-binder adhesive produced by Wall Colmonoy) to the mixed powder and stir evenly to form a first paste. The amount of the adhesive added is 6wt% of the total weight of the mixed powder and the adhesive. Then, the first paste is pressed into the original crack of the additively manufactured nickel-based high-temperature alloy part with the help of a weighing spoon, and after compaction, the paste mixed solder overflowing from the crack and not to be welded is cleaned up.

[0164] Step S2: Add a water-based adhesive (Nicrobraz s-binder adhesive produced by Wall Colmonoy) to the solder powder and stir evenly to form a second paste. The amount of the adhesive added accounts for 12wt% of the total weight of the solder powder and the adhesive. Then, the second paste is applied to the outer surface of the first paste and within 2mm of the metal substrate outside the original crack, and the total coating amount is 3 times the volume of the original crack.

[0165] Step S3: Apply the flow blocker around the second paste, and the maximum distance between the flow blocker and the second paste is 1.6 mm.

[0166] Step S4: Place the additively manufactured nickel-based high-temperature alloy parts that have been coated with the above-mentioned coating in a 110°C oven for drying for 1.5 hours, and slightly trim the unevenly coated areas of the surface solder; then place the additively manufactured nickel-based high-temperature alloy parts in a vacuum heat treatment furnace for crack repair. The temperature for crack repair treatment is 1230°C, and the insulation time is 30 minutes. After the insulation is completed, argon is filled and cooled to below 80°C. The vacuum pressure in the furnace is always no higher than 4×10 - 2 Pa.

[0167] Step S5: After the crack-repaired additively manufactured nickel-based high-temperature alloy part is taken out of the furnace, the residual solder on the outer metal of the original crack position is polished to the prototype surface state of the part.

[0168] like Fig.16 As shown in the figure, the original cracked part of the repaired part was inspected and linear defects were found in the original cracked part after X-ray inspection, indicating that the density of the repaired part was poor and there were local defects that were not welded. This was because the particle size of the filler powder was not appropriate, resulting in insufficient space utilization of the mixed solder, which in turn made the total amount of mixed solder pressed into the crack small, resulting in poor density of the weld and welding defects, so that the crack could not be successfully repaired.

[0169] Comparative Example 5

[0170] This comparative example provides a crack repair method for additively manufactured nickel-based high-temperature alloy parts, wherein:

[0171] The additively manufactured nickel-based high-temperature alloy part used in this comparative example is a part with a chemical composition of Ni-8Cr-8Co-7.85W-6Ta-5.5Al-0.7Ti-2Mo-0.08C-0.015B printed by selective laser melting technology, see Figure 1 and Figure 2 As shown, there is a through crack on the part, and the gap at the widest point of the crack is 1mm.

[0172] The filler powder used in this comparative example is an alloy powder with the same chemical composition as the parts prepared by gas atomization. The gas atomization process parameters are: melting temperature is 1560℃, powder spraying temperature is 1540℃, atomization gas is argon, and atomization pressure is 9MPa. The alloy powder obtained by atomization is sieved to obtain an alloy powder with a particle size of (-140~+325), which is the filler powder of this example.

[0173] The solder powder used in this comparative example is an alloy powder with a chemical composition of Ni-15Cr-7W-3B prepared by gas atomization. The gas atomization process parameters are: melting temperature of 1510°C, powder spraying temperature of 1490°C, atomization gas of argon, and atomization pressure of 8MPa. The alloy powder obtained by atomization is sieved to obtain an alloy powder with a particle size of -325 mesh, which is the solder powder of this example.

[0174] The crack repairing method of this comparative example comprises the following steps:

[0175] Step S0: using sand blasting combined with grinding to remove the oxide layer at the crack to be repaired.

[0176] Step S1: mechanically mix the filler powder and the solder powder in a ratio of 70%:30% to form a mixed powder, and then add a water-based adhesive (Nicrobraz s-binder adhesive produced by Wall Colmonoy) to the mixed powder and stir evenly to form a first paste. The amount of the adhesive added is 7wt% of the total weight of the mixed powder and the adhesive. Then, the first paste is pressed into the original crack of the additively manufactured nickel-based high-temperature alloy part with the help of a weighing spoon, and after compaction, the paste mixed solder overflowing from the crack and not to be welded is cleaned up.

[0177] Step S2: Add a water-based adhesive (Nicrobraz s-binder adhesive produced by Wall Colmonoy) to the solder powder and stir evenly to form a second paste. The amount of the adhesive added accounts for 12wt% of the total weight of the solder powder and the adhesive. Then, the second paste is applied to the outer surface of the first paste and within 2mm of the metal substrate outside the original crack, and the total coating amount is 2.5 times the volume of the original crack.

[0178] Step S3: Apply the flow blocker around the second paste, and the maximum distance between the flow blocker and the second paste is 1.5 mm.

[0179] Step S4: Place the additively manufactured nickel-based high-temperature alloy parts that have been coated with the above-mentioned coating in a 110°C oven for drying for 1.5 hours, and slightly trim the unevenly coated areas of the surface solder; then place the additively manufactured nickel-based high-temperature alloy parts in a vacuum heat treatment furnace for crack repair. The temperature for crack repair treatment is 1160°C, and the insulation time is 10 minutes. After the insulation is completed, argon is filled and cooled to below 80°C. The vacuum pressure in the furnace is always no higher than 4×10 - 2 Pa.

[0180] Step S5: After the crack-repaired additively manufactured nickel-based high-temperature alloy part is taken out of the furnace, the residual solder on the outer metal of the original crack position is polished to the prototype surface state of the part.

[0181] like Fig.17 As shown, the original cracked part of the repaired part was inspected, and X-rays showed that there was a defect of unwelded part at the original cracked part, indicating that the ratio of filler powder to solder powder was not within the scope of the present invention, resulting in insufficient shrinkage of the solder to the gap between the fillers, thereby affecting the density of the joint and causing unwelded part.

[0182] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention still falls within the scope of the technical solution of the present invention.

Claims

1. A crack repair method for additively manufactured nickel-based high-temperature alloy parts, characterized in that: Crack repair of additively manufactured nickel-based high-temperature alloy parts using filler powder and solder powder; Wherein, the chemical composition of the solder powder includes, by weight percentage: Cr 11.0-17.0wt%, W 5.0-9.0wt%, B 1-4wt%, C≤0.06wt%, Co≤0.1wt%, and Ni as the balance; Wherein, the chemical composition of the filler is as follows, in terms of weight percentage: Cr 6-10wt%, Co 6-10wt%, W6-10wt%, Mo 0.5-3wt%, Al 3-6wt%, Ti 0.5-2wt%, Ta3-6wt%, C≤0.2wt%, B≤0.1wt%, Hf≤2wt%, and Ni is the balance; Among them, the chemical composition of the additively manufactured nickel-based high-temperature alloy is as follows, measured in weight percentage: Cr 6-10wt%, Co 6-10wt%, W 6-10wt%, Mo 0.5-3wt%, Al 3-6wt%, Ti 0.5-2wt%, Ta 3-6wt%, C≤0.2wt%, B≤0.1wt%, Hf≤2wt%, and Ni is the balance.

2. The crack repair method for additively manufactured nickel-based high-temperature alloy parts according to claim 1, characterized in that: In the solder powder: the content of B is 2 to 3.5 wt%; and / or The filler powder has the same chemical composition as the additively manufactured nickel-based high-temperature alloy part; and / or The solder powder is spherical and / or nearly spherical, and has a particle size of -325 mesh; and / or The filler powder is spherical and / or nearly spherical, and has a particle size of -140 to +325 meshes.

3. The crack repair method for additively manufactured nickel-based high-temperature alloy parts according to claim 1 or 2, characterized in that: The preparation of the solder powder comprises: Atomizing the solder alloy to obtain alloy powder; sieving the alloy powder to select alloy powder with a set particle size as solder powder; Preferably, the parameters of the gas atomization treatment are as follows: the melting temperature is 1390-1590° C.; the powder spraying temperature is 1410-1570° C.; the atomizing gas is an inert gas, preferably argon; and the atomizing pressure is 2-10 MPa.

4. The crack repair method for additively manufactured nickel-based high-temperature alloy parts according to any one of claims 1 to 3, characterized in that: The preparation of the filler powder comprises: Performing a gas atomization treatment on the filler alloy to obtain alloy powder; performing a sieving treatment on the alloy powder, and selecting alloy powder with a set particle size as filler powder; Preferably, the parameters of the gas atomization treatment are as follows: the melting temperature is 1450-1620° C.; the powder spraying temperature is 1440-1590° C.; the atomizing gas is an inert gas, preferably argon; and the atomizing pressure is 2-10 MPa.

5. The crack repair method for additively manufactured nickel-based high-temperature alloy parts according to any one of claims 1 to 4, characterized in that: The crack repair method of the additively manufactured nickel-based high-temperature alloy part comprises the following steps: Step S1: Pressing a first paste into a crack of an additively manufactured nickel-based high-temperature alloy part; wherein the first paste comprises filler powder, solder powder and an adhesive; Step S2: applying a second paste to the crack to cover the first paste, and to an area near the crack; wherein the second paste comprises solder powder and an adhesive; Step S3: applying a flow-blocking agent around the second paste material on the additively manufactured nickel-based high-temperature alloy part; Step S4: drying and crack repairing the additively manufactured nickel-based high-temperature alloy part coated with the flow-blocking agent to obtain the additively manufactured high-temperature alloy part after crack repair.

6. The crack repair method for additively manufactured nickel-based high-temperature alloy parts according to claim 5, characterized in that: In the first paste, the content of the adhesive shall not exceed 8wt%; preferably, the adhesive is a water-based adhesive; and / or In the first paste, the mass of the solder powder accounts for 40-50 wt % of the sum of the mass of the solder powder and the filler powder; and / or The preparation step of the first paste comprises: mixing filler powder and solder powder to obtain a mixed powder; adding a binder to the mixed powder and stirring to form a first paste; and / or In the second paste, the content of the binder is 8-14 wt %.

7. The crack repair method for additively manufactured nickel-based high-temperature alloy parts according to claim 5, characterized in that: Before step S1, the method further includes step S0: removing the oxide layer at the crack to be repaired on the additively manufactured nickel-based high-temperature alloy part; and / or After step S4, the method further includes step S5: grinding the residual solder on the additively manufactured high-temperature alloy part after the crack is repaired.

8. The crack repair method for additively manufactured nickel-based high-temperature alloy parts according to claim 5, characterized in that: In the step S1: the first paste material is pressed into the crack of the additively manufactured nickel-based high-temperature alloy part, and after compaction, the first paste material overflowing from the crack to the non-to-be-welded part needs to be cleaned up; and / or In step S2: the area near the crack refers to an area no more than 2 mm away from the crack; and / or In the step S2, the coating amount of the second paste is not less than 2 times of the crack volume; and / or In step S3, the distance between the flow-blocking agent and the second paste is no more than 2 mm.

9. The crack repair method for additively manufactured nickel-based high-temperature alloy parts according to claim 5, characterized in that: In step S4: The drying temperature is 80-150° C. and the drying time is 1-3 hours; and / or The surface solder on the additively manufactured nickel-based high-temperature alloy parts needs to be trimmed after drying; and / or The crack repair process is carried out in a vacuum heat treatment furnace or a vacuum brazing furnace; preferably, the temperature of the crack repair process is 1150-1240°C, and the holding time is 10-30 minutes. Preferably, after the holding time is over, the furnace is cooled or filled with argon for cooling; preferably, before the cooling process, the vacuum pressure in the furnace is not higher than 4×10 -2 Pa.

10. The crack repair method for additively manufactured nickel-based high-temperature alloy parts according to any one of claims 1 to 9, characterized in that: The crack repair method of the additively manufactured nickel-based high-temperature alloy part is used to repair cracks with a crack gap size not greater than 1.2 mm; and / or After the crack repair, the cracks in the additively manufactured high-temperature alloy part are eliminated, and there are no unwelded defects at the repaired part.

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