Ultrafast laser in-situ composite cladding repair method

Abstract

The invention provides an ultrafast laser in-situ composite cladding repair method, and relates to the field of metal material repair. The ultrafast laser in-situ composite cladding repair method comprises the following steps: pretreating a to-be-repaired area of a titanium alloy defect part; cladding repair is conducted on the pretreated titanium alloy defect part through cladding laser, and a molten pool is formed; and the ultrafast impact laser acts on the molten pool so as to induce to generate impact waves to conduct impact forging on the molten pool. According to the method, the microscopic structure of the repairing layer can be remarkably refined, the Widmannstatten needle-shaped alpha phase is short, small and uniformly distributed, the grain size is obviously reduced, and the structure is more compact and uniform; and the microhardness of the repairing layer is effectively improved through the refined microscopic structure, and the mechanical property of the material is enhanced. According to the method, the structure uniformity and hardness of the repairing layer can be remarkably improved, and the requirement for high-performance repairing of the titanium alloy defect part is met.

Description

Technical Field

[0001] This application relates to the field of metal material repair, and in particular to an ultrafast laser in-situ composite cladding repair method. Background Technology

[0002] Titanium alloys are widely used in high-end equipment such as compressor impellers, rotating blades, and turbine guide vanes of aero engines due to their excellent specific strength, corrosion resistance, and high-temperature performance. However, titanium alloy components that have been operating under extreme environments such as long-term high temperature, high speed, and alternating stress are prone to localized failures such as surface wear, cracks, and edge damage, which seriously affect their structural integrity and service life.

[0003] Current repair technologies for titanium alloy components mainly include welding repair, thermal spraying, cold spraying, laser cladding, and metal powder bed melting (such as SLM) remanufacturing.

[0004] Among these, metal powder bed fusion processes are suitable for additive manufacturing of tiny, precision structures, but are difficult to use for in-situ repair of complex curved surfaces or large parts. Thermal spraying and cold spraying are mainly physical adhesion processes with low bonding strength; welding repair, on the other hand, involves large heat input, which can easily lead to coarsening of the microstructure and crack propagation in the heat-affected zone.

[0005] Laser cladding technology has become an important means of in-service repair of titanium alloys due to its advantages such as metallurgical bonding, controllable molten pool, and dense microstructure. However, traditional single laser cladding still faces problems such as poor thermal stability of the molten pool, uneven distribution of strengthening phases, and coarse microstructure that is prone to cracking, making it difficult to meet the high-performance requirements of titanium alloy impeller repair. Summary of the Invention

[0006] The purpose of this application is to provide an ultrafast laser in-situ composite cladding repair method to solve the above-mentioned problems.

[0007] To achieve the above objectives, this application adopts the following technical solution: A cladding repair method using ultrafast laser in-situ composite cladding includes: Pre-treatment is performed on the repairable area of ​​the titanium alloy defective part; A cladding laser is used to clad and repair pre-treated titanium alloy defective parts, forming a molten pool. An ultrafast shock laser is applied to the molten pool to induce a shock wave that impacts and forges the molten pool.

[0008] According to an embodiment of this application, the emission interval between the ultrafast shock laser and the cladding laser is 0s to 1.0s.

[0009] According to an embodiment of this application, the method further includes the step of feeding a cladding material into the molten pool, wherein the cladding material is titanium alloy powder; And / or, the cladding material is TC4 titanium alloy powder; And / or, the titanium alloy defective component includes a titanium alloy impeller.

[0010] According to an embodiment of this application, the pretreatment includes a first grinding and polishing process, a first cleaning process, and a first drying process performed sequentially.

[0011] According to an embodiment of this application, the surface roughness Ra of the titanium alloy defective part after the first grinding and polishing treatment is less than 0.4 micrometers; And / or, the first cleaning process includes ultrasonically cleaning the polished titanium alloy defective part in ethanol for 6 to 12 minutes. And / or, the first drying process includes cleaning the titanium alloy defective part by blowing it with compressed air.

[0012] According to embodiments of this application, the cladding repair method satisfies at least one of the following conditions: (1) The repetition rate of the cladding laser is 30Hz to 500Hz; (2) The spot diameter of the cladding laser is 1 mm to 5 mm; (3) The average power of the cladding laser is 120W to 400W.

[0013] According to embodiments of this application, the cladding repair method satisfies at least one of the following conditions: (4) The powder feeding rate to the cladding material is 0.05 g / min to 1 g / min; (5) The number of cladding layers is 1 to 5.

[0014] According to an embodiment of this application, the pulse width of the ultrafast shock laser is 100ps to 1000ps.

[0015] According to embodiments of this application, the cladding repair method satisfies at least one of the following conditions: (6) The spot diameter of the ultrafast shock laser is 0.2 mm to 1.0 mm; (7) The repetition rate of the ultrafast shock laser is 1 kHz to 50 kHz; (8) The average power of the ultrafast shock laser is 0.5W to 10W.

[0016] According to an embodiment of this application, after the cladding repair is completed, the method further includes: sequentially performing a second grinding and polishing treatment, a second cleaning treatment, and a second drying treatment on the repaired workpiece.

[0017] Compared with the prior art, the beneficial effects of this application include: This application introduces an ultrafast shock laser into the laser cladding repair process of titanium alloy damaged parts. The high-pressure shock wave generated by the ultrafast shock laser impacts and forges the cladding pool, significantly refining the microstructure of the repair layer. This results in shorter and more uniformly distributed Widmanstätten acicular α phases, a significantly reduced grain size, and a denser, more uniform microstructure. The refined microstructure effectively improves the microhardness of the repair layer and enhances the material's mechanical properties. Experimental results show that, compared to traditional laser cladding processes, the ultrafast laser in-situ composite cladding repair method of this application can significantly improve the microstructure uniformity and hardness of the repair layer, meeting the requirements for high-performance repair of titanium alloy damaged parts. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation on the scope of this application.

[0019] Figure 1 This is a flowchart of the ultrafast laser in-situ composite cladding repair method of this application; Figure 2 The image shows the microstructure of the titanium alloy workpiece repaired in Example 1. Figure 3 The image shows the microstructure of the titanium alloy workpiece after repair in Comparative Example 1. Figure 4 The graph shows the relationship between the microhardness and repair depth of the titanium alloy workpieces repaired in Examples 1-5 and Comparative Example 1. Figure 5 This is a graph showing the relationship between the microhardness and repair depth of the titanium alloy workpiece repaired in Example 3. Figure 6 This is a graph showing the relationship between the microhardness and repair depth of the titanium alloy workpiece repaired in Example 5. Figure 7 The graph shows the relationship between the microhardness and the repair depth of the titanium alloy workpiece after repair in Comparative Example 1. Detailed Implementation

[0020] As used in this article: "Prepared from" is synonymous with "comprising". The terms "comprising", "including", "having", "containing", or any other variations thereof as used herein are intended to cover non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or elements inherent to such composition, step, method, article, or apparatus.

[0021] The conjunction "composed of..." excludes any unspecified elements, steps, or components. If used in a claim, this phrase makes the claim closed, excluding materials other than those described, except for associated conventional impurities. When the phrase "composed of..." appears in a clause of the body of a claim rather than immediately following it, it limits only the elements described in that clause; other elements are not excluded from the claim as a whole.

[0022] When a quantity, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pair of any upper or preferred value with any lower or preferred value, regardless of whether the range is disclosed individually. For example, when the range “1–5” is disclosed, the described range should be interpreted as including ranges “1–4”, “1–3”, “1–2”, “1–2 and 4–5”, “1–3 and 5”, etc. When numerical ranges are described herein, unless otherwise stated, the range is intended to include its endpoints and all integers and fractions within that range.

[0023] In these embodiments, unless otherwise specified, the portions and percentages are all by weight.

[0024] "Parts by mass" refers to the basic unit of measurement that expresses the mass ratio of multiple components. One part can represent any unit mass, such as 1g or 2.689g. If we say that component A has "a" parts by mass and component B has "b" parts by mass, it means the ratio of the mass of component A to the mass of component B is a:b. Alternatively, it can mean that the mass of component A is aK and the mass of component B is bK (where K is any number representing a multiplier). It is important to understand that, unlike parts by mass, the sum of the mass parts of all components is not limited to 100 parts.

[0025] "And / or" is used to indicate that one or both of the described situations may occur, for example, A and / or B includes (A and B) and (A or B).

[0026] This application provides a cladding repair method using ultrafast laser in-situ composite bonding, referencing... Figure 1 ,include: Pre-treatment is performed on the repairable area of ​​the titanium alloy defective part; A cladding laser is used to clad and repair pre-treated titanium alloy defective parts, forming a molten pool. An ultrafast shock laser is applied to the molten pool to induce a shock wave that impacts and forges the molten pool.

[0027] This application, based on laser cladding repair technology, introduces an ultrafast shock laser. During the laser cladding repair process, the ultrafast shock laser impacts and forges the molten pool. In this process, the ultrafast shock laser precisely targets the solidifying molten pool, directly converting the shock wave energy into a driving force that disrupts dendrite growth and promotes heterogeneous nucleation. This achieves grain refinement and performance improvement of the overall repair layer structure from the source of solidification kinetics. Specifically, the instantaneous high-pressure shock wave of the ultrafast shock laser effectively disrupts the grain growth direction in the molten pool, promoting nucleation and recrystallization processes. This results in significantly refined grains, uniform microstructure distribution, and a substantial improvement in the microhardness and mechanical properties of the repaired part, thus achieving high-performance cladding repair of titanium alloy impellers.

[0028] According to embodiments of this application, the emission interval between the ultrafast shock laser and the cladding laser is 0 s to 1.0 s. This ensures that the shock wave acts on the molten pool while it is still in a high-temperature plastic state or just beginning to solidify, facilitating "in-situ compositing." If the emission interval between the ultrafast shock laser and the cladding laser is greater than 1.0 s, the molten pool has completely solidified, and the shock wave can only modify the surface layer, failing to affect the solidified structure.

[0029] For example, the emission interval between ultrafast shock lasers and cladding lasers can be any value between 0s, 0.1s, 0.2s, 0.3s, 0.4s, 0.5s, 0.6s, 0.7s, 0.8s, 0.9s, 1.0s, or 0s to 1.0s.

[0030] When the emission interval between the ultrafast shock laser and the cladding laser is 0s, the ultrafast shock laser and the cladding laser are emitted simultaneously, and the shock wave can directly act on the growing molten pool, directly breaking and disrupting the dendrites.

[0031] In this application, the emission time of the cladding laser is no later than the emission time of the ultrafast shock laser; that is, the ultrafast shock laser and the cladding laser can be emitted synchronously or with a delay. This allows the shock wave from the ultrafast laser to directly act on the molten pool. At this time, the shock wave can powerfully stir the molten pool, breaking up the growing coarse grains and forcing the molten metal to form more and finer crystal nuclei, thereby directly generating a repair layer with fine grains, dense structure, and excellent performance from within.

[0032] If an ultrafast shock laser is fired first, followed by a cladding laser, it only performs surface strengthening on the part's surface, forming a very thin strengthening layer. The high temperature of the cladding laser will then completely melt away this thin strengthening area, and the previous strengthening effect will disappear completely, making no contribution to the internal structure of the final repair layer.

[0033] If laser shock cladding is applied to the surface of the cladding layer after traditional laser cladding has been completed and completely cooled, the ultrafast laser will only affect the solidified cladding layer. The resulting shock wave effect can only achieve plastic deformation and introduce residual stress field on the surface, which falls under the category of surface modification. When the solid cladding layer is subjected to impact, the coarse Widmanstätten structure already formed inside will not change, and its effect is inferior to the solution proposed in this application.

[0034] According to an embodiment of this application, the method further includes the step of feeding a cladding material into the molten pool, wherein the cladding material is titanium alloy powder.

[0035] Under the action of cladding laser, the titanium alloy defective parts and cladding material form a molten pool. The ultrafast impact laser applies impact forging to the molten pool, which promotes grain refinement and uniform structure, improves the performance of the cladding layer, and is conducive to realizing high-performance cladding repair of titanium alloy impellers by ultrafast laser in-situ composite.

[0036] In some embodiments, the method further includes: conveying cladding material into the molten pool via a powder feeding device.

[0037] In some embodiments, the cladding material is TC4 titanium alloy powder; In some embodiments, the titanium alloy defective component includes a titanium alloy impeller.

[0038] According to an embodiment of this application, the pretreatment includes a first grinding and polishing process, a first cleaning process, and a first drying process performed sequentially.

[0039] According to an embodiment of this application, the surface roughness Ra of the titanium alloy defective part after the first grinding and polishing treatment is less than 0.4 micrometers; through the first grinding and polishing treatment, irregular scratches, protrusions and other defects on the surface of the damaged part of the titanium alloy defective part can be removed, so that the surface roughness of the damaged part of the titanium alloy defective part reaches a machinable level.

[0040] In some embodiments, the first grinding and polishing process includes: polishing and grinding the area to be repaired of the titanium alloy defective part using sandpaper with a grit of 600 to 2000 grit (e.g., 600 grit, 800 grit, 1000 grit, 1200 grit, 1400 grit, 1600 grit, 1800 grit, 2000 grit or any value between 600 grit and 2000 grit).

[0041] And / or, the first cleaning process includes ultrasonically cleaning the polished titanium alloy defective part in ethanol for 6 to 12 minutes (e.g., 6 minutes, 7 minutes, 8 minutes, 9 minutes, 10 minutes, 11 minutes, 12 minutes or any value between 6 and 12 minutes); through the first cleaning process, the wear debris and other impurities on the surface of the titanium alloy defective part can be removed, thereby ensuring the cleanliness of the workpiece surface, so as to facilitate subsequent repair.

[0042] And / or, the first drying process includes cleaning the titanium alloy defective part by blowing it with compressed air.

[0043] According to embodiments of this application, the repetition rate of the cladding laser is 30Hz to 500Hz. Setting the repetition rate of the cladding laser to 30Hz to 500Hz is based on a comprehensive consideration of molten pool stability, heat input uniformity, and the ability to control the repair morphology. When the repetition rate of the cladding laser is too low, the pulse interval is too long, and the formation and solidification process of the molten pool is discontinuous, which may lead to obvious pulsating marks similar to "fish scales" on the repair layer, affecting surface smoothness and interlayer bonding. Conversely, when the repetition rate of the cladding laser is too high, the pulse superposition effect is significant, and the heat input tends to be continuous. Although a smoother surface can be obtained, it weakens the unique instantaneous high energy density advantage of pulsed lasers, reduces the precise control over the shape and depth of the molten pool, and may expand the heat-affected zone. Therefore, when the repetition rate of the cladding laser is 30Hz to 500Hz, sufficient single-pulse energy is ensured to achieve good melting depth and metallurgical bonding, while a stable and uniform cladding channel can be obtained through appropriate pulse superposition, thereby meeting different process requirements from high-precision repair to high-efficiency coverage.

[0044] For example, the repetition rate of the cladding laser can be 30Hz, 50Hz, 100Hz, 150Hz, 200Hz, 250Hz, 300Hz, 350Hz, 400Hz, 450Hz, 500Hz, or any value between 30Hz and 500Hz.

[0045] According to embodiments of this application, the spot diameter of the cladding laser is 1mm to 5mm. The spot size directly determines the energy density and repair efficiency. When the spot diameter of the cladding laser is 1mm to 5mm, it can balance energy density and process stability, while also considering repair accuracy and efficiency—small spots (e.g., 1mm) are suitable for high-precision repair of narrow grooves and cracks, while large spots (e.g., 5mm) can improve the efficiency of large-area repair. If the spot diameter of the cladding laser is too small, it is prone to local overheating and evaporation; if the spot diameter of the cladding laser is too large, it may be impossible to form a stable molten pool due to insufficient energy density.

[0046] For example, the spot diameter of the cladding laser can be 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, or any value between 1 mm and 5 mm.

[0047] According to embodiments of this application, the average power of the cladding laser is 120W to 400W. The average power of the cladding laser, together with the spot diameter and scanning speed, determines the heat input of the molten pool. A lower power of 120W is sufficient to melt TC4 titanium alloy powder and the substrate surface at the appropriate spot size and scanning speed; an upper power of 400W can meet the energy requirements at higher scanning speeds. When the average power of the cladding laser is 120W to 400W, reliable metallurgical bonding is ensured while avoiding overheating of the substrate or excessive element loss due to excessive power.

[0048] For example, the average power of the cladding laser is 120W, 150W, 200W, 250W, 300W, 350W, 400W, or any value between 120W and 400W.

[0049] According to embodiments of this application, the powder feed rate of the cladding material is 0.05 g / min to 1 g / min. The powder feed rate of the cladding material is precisely matched with the laser power and scanning speed. When the powder feed rate of the cladding material is 0.05 g / min to 1 g / min, a dynamic balance between the melting efficiency and deposition efficiency of the powder can be ensured. If the powder feed rate of the cladding material is too low, it will lead to insufficient powder supply, forming a "deficient cladding layer" or directly burning off the substrate; if the powder feed rate of the cladding material is too high, unmelted particles may be formed because the powder cannot be completely melted, reducing the density.

[0050] For example, the powder feeding rate to the cladding material can be 0.05 g / min, 0.06 g / min, 0.07 g / min, 0.08 g / min, 0.09 g / min, 1 g / min, or any value between 0.05 g / min and 1 g / min.

[0051] According to embodiments of this application, the number of cladding layers is 1 to 5. The number of cladding layers refers to the total number of material layers deposited sequentially during the laser repair process, directly corresponding to the overall thickness and three-dimensional morphology of the repaired area. Each cladding layer undergoes a "powder feeding" process. melt The complete metallurgical process of "solidification" allows for precise filling of defects through controlled layer-by-layer stacking, and enables optimization of the internal microstructure through interlayer process adjustments (such as laser parameters and path offset). When the number of cladding layers is 1 to 5, it ensures that while achieving the required repair thickness, the uniformity, density, and high performance of the overall microstructure of the repair layer are maintained, ensuring that each layer can obtain a refined solidification microstructure. One layer is suitable for strengthening and repairing surface damage; two to five layers can effectively fill common local defects, grooves, or cracks. When the number of cladding layers is too large, repeated thermal cycling will cause a heat accumulation effect, leading to coarsening of the microstructure under the repair layer, a significant increase in internal stress, and even the risk of cracking, thus severely offsetting the grain refinement advantage brought by ultrafast lasers.

[0052] For example, the number of cladding layers can be 1, 2, 3, 4, 5, or any value between 1 and 5 layers.

[0053] According to embodiments of this application, the pulse width of the ultrafast shock laser is 100 ps to 1000 ps. When the pulse width of the ultrafast shock laser is 100 ps to 1000 ps, ​​the laser energy is deposited on the material surface in a very short time, causing the surface material to instantly vaporize and plasmaize, generating a high-pressure (GPa level) shock wave with a very shallow heat-affected zone. If the pulse width of the ultrafast shock laser is too small, the equipment cost increases sharply while the shock wave pressure gain is limited; if the pulse width of the ultrafast shock laser is too large, the thermal effect dominates, and the impact forging effect cannot be achieved.

[0054] For example, the pulse width of an ultrafast shock laser can be any value between 100ps, 200ps, 300ps, 400ps, 500ps, 600ps, 700ps, 800ps, 900ps, 1000ps, or 100ps to 1000ps.

[0055] According to embodiments of this application, the spot diameter of the ultrafast shock laser is 0.2 mm to 1.0 mm. This achieves an optimal balance between impact pressure and effective area. The spot diameter directly determines the energy density and effective area of ​​the shock wave: when the spot diameter of the ultrafast shock laser is too small, the energy is too concentrated, potentially generating extreme high pressure that could lead to molten pool splashing or microscopic defects; conversely, when the spot diameter is too large, the energy density is insufficient to generate a shock wave of sufficient intensity to effectively forge the interior of the molten pool and achieve grain refinement. Therefore, setting the spot diameter of the ultrafast shock laser to within 0.2 mm to 1.0 mm ensures both sufficient high-pressure impact to disrupt the molten pool solidification process and uniform coverage of the molten pool area by the impact, thus achieving effective control over the repair layer structure.

[0056] For example, the spot diameter of the ultrafast shock laser can be 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, or any value between 0.2 mm and 1.0 mm.

[0057] According to embodiments of this application, the repetition rate of the ultrafast impact laser is 1 kHz to 50 kHz. This allows it to match the scanning speed of the cladding laser, achieving continuous and uniform impact coverage of the moving molten pool. The repetition rate determines the number of impact strikes per unit time: when the repetition rate is too low, the interval between two impacts is too long, resulting in overly sparse impact points for a high-speed scanning molten pool, leading to discontinuous forging action and uneven microstructure refinement; when the repetition rate is too high, although denser impacts can be achieved, it places extremely high demands on the laser and may cause energy accumulation and increased thermal effects due to excessively short pulse intervals. Therefore, when the repetition rate of the ultrafast impact laser is 1 kHz to 50 kHz, it can effectively coordinate with the cladding scanning speed while ensuring forging uniformity.

[0058] For example, the repetition rate of an ultrafast shock laser can be 1 kHz, 5 kHz, 10 kHz, 15 kHz, 20 kHz, 25 kHz, 30 kHz, 35 kHz, 40 kHz, 45 kHz, 50 kHz, or any value between 1 kHz and 50 kHz.

[0059] According to embodiments of this application, the average power of the ultrafast shock laser is 0.5W to 10W. This ensures a sufficiently significant shock wave effect while avoiding unnecessary thermal interference to the molten pool. Average power is the energy basis for forming an effective shock wave: if the average power of the ultrafast shock laser is too low, the laser energy is insufficient to induce an observable shock wave that alters solidification behavior, resulting in negligible forging effect; if the average power of the ultrafast shock laser is too high, significant thermal effects may occur due to excessive energy input, even leading to secondary melting or vaporization of the molten pool surface, which contradicts the original intention of using ultrafast lasers to achieve "cold forging." When the average power of the ultrafast shock laser is 0.5W to 10W, the sufficiency of the mechanical action of the shock wave is guaranteed, while its accompanying heat input is strictly limited.

[0060] For example, the average power of an ultrafast shock laser is 0.5W, 1W, 2W, 3W, 4W, 5W, 6W, 7W, 8W, 9W, 10W, or any value between 0.5W and 10W.

[0061] Technicians can rationally set the parameters of the cladding laser and ultrafast impact laser based on the specific shape and size of the pre-treated titanium alloy impeller defect, combined with the required repair layer thickness and performance indicators. Using these parameters, software can be used to generate the laser scanning path, determining its speed and length.

[0062] Based on the determined cladding laser parameters, ultrafast shock laser parameters, and laser path control information, the laser emission equipment can be controlled to achieve synchronous or delayed emission of the cladding laser and the ultrafast shock laser. The laser beam covers the repair area layer by layer according to the scanning speed and length of the predetermined scanning trajectory, completing the deposition of a repair layer of predetermined thickness.

[0063] According to an embodiment of this application, after the cladding repair is completed, the method further includes: sequentially performing a second grinding and polishing treatment, a second cleaning treatment, and a second drying treatment on the repaired workpiece.

[0064] The implementation schemes of this application will be described in detail below with reference to specific embodiments. However, those skilled in the art will understand that the following embodiments are only for illustrating this application and should not be regarded as limiting the scope of this application. Unless otherwise specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments used without specified manufacturers are all conventional products that can be purchased commercially.

[0065] Example 1 Example 1 provides a cladding repair method using ultrafast laser in-situ composite cladding, comprising: S1. Pre-treat the area to be repaired of the damaged titanium alloy impeller to obtain the pre-treated damaged titanium alloy impeller.

[0066] S11. Use 1200-grit sandpaper to grind and polish the area to be repaired of the titanium alloy impeller until the surface roughness Ra of the area to be repaired of the titanium alloy impeller is less than 0.4 μm.

[0067] S12. The polished titanium alloy impeller defective part is placed in anhydrous ethanol for ultrasonic cleaning and the cleaning is continued for 10 minutes to obtain the cleaned titanium alloy impeller defective part.

[0068] S13. The titanium alloy damaged parts are cleaned by blowing with compressed air, and the cleaned titanium alloy impeller damaged parts are dried to obtain pre-treated titanium alloy impeller damaged parts.

[0069] S2. Using cladding laser to clad repair the pre-treated titanium alloy impeller defective parts to form a molten pool; The laser scanning path is generated using computer-aided design (CAD) and computer-aided manufacturing (CAM) software. The speed and length of the scanning path are determined, and the path design must cover the area to be repaired.

[0070] Following the preset laser path, the cladding laser is focused on the surface of the repair area of ​​the pre-treated titanium alloy impeller defect to form a molten pool. The powder feeding system simultaneously feeds the cladding material into the molten pool at a set rate. The cladding material is TC4 titanium alloy powder, which achieves effective fusion of materials.

[0071] In Example 1, the cladding laser parameters were as follows: the repetition rate of the cladding laser was 30 Hz; the spot diameter of the cladding laser was 1.8 mm; the average power of the cladding laser was 157.95 W; the powder feeding rate of the cladding material was 0.1 g / min; and the number of cladding layers was 1.

[0072] S3. During the laser cladding repair process, an ultrafast shock laser is emitted into the molten pool generated during the laser cladding repair of the pre-treated titanium alloy impeller defect. The ultrafast shock laser induces a high-pressure shock wave to impact and forge the cladding molten pool, so that the repaired titanium alloy impeller defect is obtained after the laser cladding repair process.

[0073] In Example 1, the ultrafast shock laser parameters are as follows: pulse width is 674.1 ps; spot diameter is 0.65 mm; repetition rate is 1 kHz; average power is 2 W; and the emission interval between the ultrafast shock laser and the cladding laser is 0 s.

[0074] In Example 1, the scanning speed of the cladding laser and the ultrafast shock laser is 3.5 mm / s, and the scanning length is 30 mm.

[0075] The laser emitting equipment is controlled to achieve synchronous emission of cladding laser and ultrafast impact laser. The laser beam covers the repair area layer by layer according to the scanning speed and length of the predetermined scanning trajectory. The number of cladding layers is set according to the depth of the defect and the repair requirements to complete the deposition of the repair layer of the predetermined thickness.

[0076] S4. Post-processing and Performance Testing After the cladding repair is completed, the repaired part is allowed to cool naturally to room temperature, and then post-processing is carried out, including grinding, polishing, cleaning and drying. The specific operation steps and detailed parameters of the post-processing in Example 1 are the same as those of the pre-processing step, and the repaired part is finally obtained.

[0077] Example 2 The difference between Example 2 and Example 1 is that the emission interval between the ultrafast shock laser and the cladding laser in Example 2 is 0.2 s. Everything else is the same as in Example 1.

[0078] Example 3 The difference between Example 3 and Example 1 is that the emission interval between the ultrafast shock laser and the cladding laser in Example 3 is 0.4 s. Everything else is the same as in Example 1.

[0079] Example 4 The difference between Example 4 and Example 1 is that the emission interval between the ultrafast shock laser and the cladding laser in Example 4 is 0.6 s. Everything else is the same as in Example 1.

[0080] Example 5 The difference between Example 5 and Example 1 is that the emission interval between the ultrafast shock laser and the cladding laser in Example 5 is 0.8 s. Everything else is the same as in Example 1.

[0081] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that Comparative Example 1 uses only a cladding laser for laser cladding repair and does not introduce an ultrafast impact laser; that is, the power of the ultrafast impact laser in Comparative Example 1 is 0W. Everything else is the same as in Example 1.

[0082] After the repaired titanium alloy impeller defect was cooled and post-treated, a sample was taken from the repaired area to prepare a metallographic specimen.

[0083] The cross-section of the repair layer was observed using a metallographic microscope, and metallographic images were acquired at the same magnification to compare and analyze the differences in the morphology of the repair layer before and after the introduction of ultrafast shock laser, including grain size, morphology and uniformity of distribution.

[0084] The hardness of the repair layer cross section was tested using a microhardness tester. The test points were distributed along the depth direction of the repair layer with a fixed spacing, and the variation of microhardness with depth was recorded.

[0085] The microstructure of the repaired titanium alloy workpiece in Example 1 is shown below. Figure 2 As shown, by Figure 2 It can be seen that the microstructure consists of fine and uniformly distributed Widmanstätten acicular α phases. The acicular structures are short and fine, with random arrangement and significantly refined grains.

[0086] The microstructure of the repaired titanium alloy workpiece in Comparative Example 1 is shown in the figure below. Figure 3 As shown, Figure 3 and Figure 2 The repair depth is the same, by Figure 3 It can be seen that, Figure 3 The microstructure consists of relatively coarse and directional Widmanstätten α phases, with long and regular needle-like structures and relatively large grain size.

[0087] The relationship between microhardness and repair depth of the titanium alloy workpieces repaired in Examples 1-5 and Comparative Example 1 is shown in the figure below. Figure 4 As shown, by Figure 4 It can be seen that, compared with not introducing ultrafast impact laser, introducing ultrafast impact laser can improve the microhardness of the repaired part within a certain depth. At the same time, the interval time will affect the improvement effect.

[0088] When analyzing microhardness data, it is important to clarify that due to the inherent microscopic inhomogeneities in the material's microstructure (such as grain orientation, phase distribution, and local defects), single-point hardness test values ​​will exhibit a certain range of normal fluctuations. Therefore, performance comparisons should be based on statistically significant overall trends and average values. Figure 4 As shown, although there are slight fluctuations in each hardness curve, reflecting the natural differences in the local structure of the material, the hardness curves of Examples 1 to 5, as a whole, consistently and significantly occupy a position above the curve of Comparative Example 1. At any given depth coordinate, the average hardness value corresponding to the example with the introduction of ultrafast shock laser is clearly higher than that of the comparative example without the introduction of shock laser. For example, from Figure 5 It can be seen that, in Example 3, when the repair depth of the titanium alloy workpiece was 0-120 μm, the average microhardness was 473.91 HV. Figure 6 It can be seen that, in Example 5, when the repair depth of the titanium alloy workpiece was 0-120 μm, the average microhardness was 438.84 HV. Figure 7 It can be seen that when the repair depth of the titanium alloy workpiece repaired in Comparative Example 1 is 0-120μm, the average microhardness is 397.75HV. That is, at the same repair depth, the average hardness value of the embodiment is significantly higher than that of Comparative Example 1.

[0089] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

[0090] Furthermore, those skilled in the art will understand that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of this application and form different embodiments. For example, in the foregoing claims, any of the claimed embodiments can be used in any combination. The information disclosed in this background section is intended only to enhance the understanding of the general background of this application and should not be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

Claims

1. A cladding repair method using ultrafast laser in-situ composite cladding, characterized in that, include: Pre-treatment is performed on the repairable area of ​​the titanium alloy defective part; A cladding laser is used to clad and repair pre-treated titanium alloy defective parts, forming a molten pool. An ultrafast shock laser is applied to the molten pool to induce a shock wave that impacts and forges the molten pool.

2. The ultrafast laser in-situ composite cladding repair method according to claim 1, characterized in that, The emission interval between the ultrafast shock laser and the cladding laser is 0s to 1.0s.

3. The ultrafast laser in-situ composite cladding repair method according to claim 1, characterized in that, The method further includes the step of feeding a cladding material into the molten pool, wherein the cladding material is titanium alloy powder; And / or, the cladding material is TC4 titanium alloy powder; And / or, the titanium alloy defective component includes a titanium alloy impeller.

4. The ultrafast laser in-situ composite cladding repair method according to claim 1, characterized in that, The pretreatment includes a first grinding and polishing process, a first cleaning process, and a first drying process performed sequentially.

5. The ultrafast laser in-situ composite cladding repair method according to claim 4, characterized in that, The surface roughness Ra of the first polished titanium alloy defective part is less than 0.4 micrometers; And / or, the first cleaning process includes ultrasonically cleaning the polished titanium alloy defective part in ethanol for 6 to 12 minutes. And / or, the first drying process includes cleaning the titanium alloy defective part by blowing it with compressed air.

6. The ultrafast laser in-situ composite cladding repair method according to claim 1, characterized in that, The cladding repair method satisfies at least one of the following conditions: (1) The repetition rate of the cladding laser is 30Hz to 500Hz; (2) The spot diameter of the cladding laser is 1 mm to 5 mm; (3) The average power of the cladding laser is 120W to 400W.

7. The ultrafast laser in-situ composite cladding repair method according to claim 3, characterized in that, The cladding repair method satisfies at least one of the following conditions: (4) The powder feeding rate to the cladding material is 0.05 g / min to 1 g / min; (5) The number of cladding layers is 1 to 5.

8. The ultrafast laser in-situ composite cladding repair method according to claim 1, characterized in that, The pulse width of the ultrafast shock laser is 100ps to 1000ps.

9. The ultrafast laser in-situ composite cladding repair method according to claim 8, characterized in that, The cladding repair method satisfies at least one of the following conditions: (6) The spot diameter of the ultrafast shock laser is 0.2 mm to 1.0 mm; (7) The repetition rate of the ultrafast shock laser is 1 kHz to 50 kHz; (8) The average power of the ultrafast shock laser is 0.5W to 10W.

10. The ultrafast laser in-situ composite cladding repair method according to any one of claims 1-9, characterized in that, After the cladding repair is completed, the method further includes: performing a second grinding and polishing treatment, a second cleaning treatment, and a second drying treatment on the repaired workpiece in sequence.

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