Crack repairing method for nickel-based single crystal alloy
By adopting joint treatment of decontamination, crack propagation, plasma treatment and laser cladding on nickel-based single crystal alloys, the problems of tissue defects and high equipment cost in traditional repair methods are solved, and efficient and uniform crack repair of nickel-based single crystal alloys is achieved.
Patent Information
- Application Number
- CN202411817942.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-11
- Publication Date
- 2025-03-14
AI Technical Summary
The crack repair method of traditional nickel-based single crystal alloys has defects such as new surface cracks, residual stress, and pores in the tissue. Thermal isostatic pressing equipment is expensive and has high operating and maintenance costs, making it difficult to achieve uniform repair of large or complex-shaped components.
The crack repair method of nickel-based single crystal alloy based on forming the quasi-single crystal repair layer structure is adopted, including detergent treatment, crack propagation treatment, plasma treatment of clad powder to form a clad thin plate, and combined treatment of laser clad and water cooling.
On the basis of maintaining the original strength and ductility of the base material, it can reduce the negative effects of the heat-affected zone on the joint, effectively repair cracks in nickel-based single-crystal high-temperature alloy sheets, and reduce repair costs.
Smart Images
Figure CN119615149A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of metal material connection, and specifically provides a crack repair method for a nickel-based single crystal alloy with excellent mechanical properties obtained by forming a quasi-single crystal repair layer structure. Background Art
[0002] Since nickel-based alloys can still maintain excellent mechanical properties under high temperature and high pressure environments, nickel-based single crystal alloys are widely used in hot end components of various engines, such as engine blades. However, nickel-based alloys work in high temperature, high pressure and corrosive atmosphere environments for a long time, and defects are very likely to occur on the surface, which will affect the service life of the blades and pose a great safety hazard to the engine. Therefore, in order to ensure the safety of the aircraft, defective blades must be replaced or repaired in a timely manner. Single crystal high-temperature alloys are expensive to manufacture, and the cost of replacing blades is relatively high. Therefore, repairing nickel-based single crystal alloy blades has received more widespread attention. Existing repair methods have many defects. For example, although traditional repair technology can repair alloy surface cracks to a certain extent, it is easy to cause new surface cracks, residual stress, pores and other defects in the organization. Moreover, the selection of traditional hot isostatic pressing parameters has a great influence on the repair results. Inappropriate parameters may not be able to effectively repair defects, and may even cause internal recrystallization near the healing holes, affecting material properties. In addition, hot isostatic pressing equipment is expensive, with high operating and maintenance costs, and requires professional technicians to operate, which is difficult for small and medium-sized enterprises to afford. For large or complex-shaped nickel-based high-temperature alloy parts, traditional processing methods cannot guarantee the uniformity of the repair results, resulting in differences in performance of different parts.
[0003] Therefore, proposing a new crack repair method for nickel-based single crystal alloys has become an urgent problem to be solved. Summary of the invention
[0004] In view of this, the purpose of the present invention is to provide a crack repair method for nickel-based single crystal alloy to solve the problems existing in traditional repair methods.
[0005] The present invention provides a method for repairing cracks in a nickel-based single crystal alloy, comprising:
[0006] The nickel-based single crystal alloy to be repaired is subjected to a decontamination treatment, wherein the nickel-based single crystal alloy comprises, by mass ratio, Cr: 6.0-8.0, Co: 6.0-8.0, W: 4.0-6.0, Al: 6.0-6.5, Ta: 6.0-7.0, Mo: 1.0-2.0, Re: 2.5-3.5, and Ni: 60-68;
[0007] Crack extension treatment of decontaminated nickel-based single crystal alloy;
[0008] preparing cladding powder and performing plasma treatment, and then pressing the cladding powder after the plasma treatment into a cladding sheet, wherein the cladding powder is GH4738 powder material;
[0009] Inserting the cladding thin plate into the expanded crack to be repaired, and repairing the crack by using a laser cladding method;
[0010] The cladding layer is cooled by water cooling.
[0011] Preferably, the decontamination process is as follows: first, wash away the oil stains on the surface of the nickel-based single crystal alloy with alcohol, then use 280# and 400# sandpaper to grind away the oxide film on the surface of the nickel-based single crystal alloy, then wash with alcohol, and finally blow dry with a hair dryer.
[0012] Further preferably, the crack extension processing method is as follows: a groove is set at the crack, and the groove shape is I-type.
[0013] More preferably, the plasma treatment conditions are as follows: the power-on voltage is 40 to 60 V, the current is 1.6 to 2.0 A, and the power-on time is 6 to 10 min.
[0014] Further preferably, a binder is added to the cladding powder when pressing it into a cladding thin plate.
[0015] Further preferably, the laser cladding method is as follows: introducing argon gas for gas protection, and performing laser cladding under the following parameter conditions: laser power 800-1400W, laser scanning speed 2-4mm / s, and laser spot size 2-3mm.
[0016] More preferably, the method of cooling the cladding layer by water cooling is as follows: the cladding layer is circulated and cooled at a flow rate of 0.5 to 2 L / min.
[0017] The crack repair method of the nickel-based single crystal alloy provided by the present invention, through the combined treatment of plasma-treated cladding thin plate, laser cladding and water cooling, makes the repair layer structure and the base material structure have the same tissue orientation, can maintain the original strength and ductility of the parent material, and at the same time reduce the negative effect of the heat-affected zone on the joint, and can effectively repair the cracks of the nickel-based single crystal high-temperature alloy plate. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments:
[0019] Figure 1 This is a microstructure image of the nickel-based single crystal alloy substrate of Example 1 of the present invention;
[0020] Figure 2This is a microstructure picture of the repair interface of the nickel-based single crystal high-temperature alloy repair plate in Example 1 of the present invention;
[0021] Figure 3 This is the grain orientation diagram of the repair interface of the nickel-based single crystal high-temperature alloy repair plate described in Example 1. DETAILED DESCRIPTION
[0022] The present invention will be further explained below in conjunction with specific implementation schemes, but the present invention is not limited thereto.
[0023] Since nickel-based high-temperature alloys are multi-element strengthened phase-change-free alloys, composition and structure segregation are very likely to occur during fusion welding additive repair, and solidification cracks, liquefaction cracks, strain aging cracks and plastic loss cracks are likely to occur. In order to solve the above problems, the present invention provides a new crack repair method for nickel-based single crystal alloys.
[0024] Example 1
[0025] The crack repair method of nickel-based single crystal alloy is as follows:
[0026] (1) To ensure that the nickel-based single crystal high-temperature alloy plate is not contaminated and to prevent impurities from affecting the repair process, the nickel-based single crystal alloy to be repaired is first decontaminated with alcohol. The specific steps are as follows: first, the oil on the surface of the nickel-based single crystal alloy is washed away with alcohol, and then the oxide film on the surface of the nickel-based single crystal alloy plate is polished off with 280# and 400# sandpaper respectively, and then washed with alcohol, and finally dried with a hair dryer; wherein the nickel-based single crystal high-temperature alloy plate includes, by mass ratio, Cr: 7.0, Co: 7.5, W: 5.0, Al: 6.2, Ta: 6.5, Mo: 1.5, Re: 3.0, Ni: 63.3, and the thickness of the plate is 10 mm;
[0027] (2) Determine the repair trajectory, expand the crack along the direction of the crack, and set a groove at the repair position of the workpiece to be repaired, and the groove shape is I-type;
[0028] (3) After the cladding powder (GH4738 powder material) was subjected to plasma treatment with a voltage of 50 V, a current of 1.8 A, and a power-on time of 8 min, it was placed on a water-cooled copper workbench, a binder was added, and then pressed into a 2 mm cladding sheet;
[0029] (4) The workpiece to be repaired is assembled on a water-cooled copper workbench, the cladding sheet is inserted into the expanded crack to be repaired, and the crack is repaired by a laser cladding method, wherein, under the condition of introducing argon gas for gas protection, the process parameters of the laser cladding method are: laser power of 1200 W, laser speed of 2 mm / s, and laser spot size of 2 mm;
[0030] (5) The cladding layer is cooled by circulating water at a flow rate of 0.5 L / min.
[0031] Example 2
[0032] The crack repair method of nickel-based single crystal alloy is as follows:
[0033] (1) To ensure that the nickel-based single crystal high-temperature alloy plate is not contaminated and to prevent impurities from affecting the repair process, the nickel-based single crystal alloy to be repaired is first decontaminated with alcohol. The specific steps are as follows: first, the oil on the surface of the nickel-based single crystal alloy is washed away with alcohol, and then the oxide film on the surface of the nickel-based single crystal alloy plate is polished off with 280# and 400# sandpaper respectively, and then washed with alcohol, and finally dried with a hair dryer; wherein the nickel-based single crystal high-temperature alloy plate comprises, by mass ratio, Cr: 8.0, Co: 6.5, W: 5.0, Al: 6.2, Ta: 6.5, Mo: 3.0, Re: 3.0, Ni: 61.8, and the thickness of the plate is 5 mm;
[0034] (2) Determine the repair trajectory, expand the crack along the direction of the crack, and set a groove at the repair position of the workpiece to be repaired, and the groove shape is I-type;
[0035] (3) After the cladding powder (GH4738 powder material) was subjected to plasma treatment at a voltage of 40 V, a current of 2 A, and a power-on time of 6 min, it was placed on a water-cooled copper workbench, a binder was added, and then pressed into a 3 mm cladding sheet;
[0036] (4) The workpiece to be repaired is assembled on a water-cooled copper workbench, the cladding sheet is inserted into the expanded crack to be repaired, and the crack is repaired by a laser cladding method, wherein, under the condition of introducing argon gas for gas protection, the process parameters of the laser cladding method are: laser power of 1400 W, laser speed of 4 mm / s, and laser spot size of 3 mm;
[0037] (5) The water-cooled copper workbench circulates water to cool the cladding layer at a flow rate of 1 L / min.
[0038] Example 3
[0039] The crack repair method of nickel-based single crystal alloy is as follows:
[0040] (1) To ensure that the nickel-based single crystal high-temperature alloy plate is not contaminated and to prevent impurities from affecting the repair process, the nickel-based single crystal alloy to be repaired is first decontaminated with alcohol. The specific steps are as follows: first, the oil on the surface of the nickel-based single crystal alloy is washed away with alcohol, and then the oxide film on the surface of the nickel-based single crystal alloy plate is polished off with 280# and 400# sandpaper respectively, and then washed with alcohol, and finally dried with a hair dryer; wherein the nickel-based single crystal high-temperature alloy plate comprises, by mass ratio, Cr: 8.0, Co: 6.5, W: 5.0, Al: 6.2, Ta: 6.5, Mo: 3.0, Re: 3.0, Ni: 61.8, and the thickness of the plate is 5 mm;
[0041] (2) Determine the repair trajectory, expand the crack along the direction of the crack, and set a groove at the repair position of the workpiece to be repaired, and the groove shape is I-type;
[0042] (3) After the cladding powder (GH4738 powder material) was subjected to plasma treatment at a voltage of 60 V, a current of 1.6 A, and a power-on time of 10 min, it was placed on a water-cooled copper workbench, a binder was added, and then pressed into a 1 mm cladding sheet;
[0043] (4) The workpiece to be repaired is assembled on a water-cooled copper workbench, the cladding sheet is inserted into the expanded crack to be repaired, and the crack is repaired by a laser cladding method, wherein, under the condition of introducing argon gas for gas protection, the process parameters of the laser cladding method are: laser power of 800 W, laser speed of 3 mm / s, and laser spot size of 2 mm;
[0044] (5) The water-cooled copper workbench circulates water to cool the cladding layer at a flow rate of 2 L / min.
[0045] Comparative Example 1
[0046] The difference from Example 1 is that the cladding powder is not pressed into a cladding thin plate, and the repair is carried out by a traditional laser synchronous powder feeding method. The remaining steps and conditions are the same as those in Example 1.
[0047] Comparative Example 2
[0048] The difference from Example 1 is that the cladding powder is not treated with plasma, and the remaining steps and conditions are the same as those of Example 1.
[0049] Comparative Example 3
[0050] The difference from Example 1 is that no water cooling control is performed after repair, and the remaining steps and conditions are the same as those of Example 1. The repaired plate is obtained accordingly.
[0051] The repaired plates obtained in Examples 1 to 3 and Comparative Examples 1 to 3 were tested, and the results were as follows:
[0052] After testing, the tensile strength of the repaired plate of Example 1 is 1126.1MPa, and the elongation is 12.2%. Compared with the substrate, the tensile strength is increased by 3%, and the elongation is increased by 3.5%; the tensile strength of the repaired plate of Example 2 is 1003.1MPa, and the elongation is 10.4%. The tensile strength is 92% of the tensile strength of the substrate, and the elongation is 1.7% higher than the elongation of the substrate; the tensile strength of the repaired plate of Example 3 is 996.3MPa, and the elongation is 9.4%. The tensile strength is 91% of the tensile strength of the substrate, and the elongation is 0.7% higher than the substrate.
[0053] The nickel-based single crystal alloy to be repaired used in Examples 1 to 3 and Comparative Examples 1 to 3 has a typical cross-shaped γ-shaped single crystal structure in the as-cast state. Figure 1 : is the microstructure diagram of the nickel-based single crystal alloy substrate to be repaired in the embodiment.
[0054] The repaired plates obtained in Examples 1 to 3 have good bonding properties, distinct fusion lines, and no obvious defects such as heat-affected zones and pores. Figure 2 This is the microstructure diagram of the repair interface of the repair plate obtained in Example 1.
[0055] The repair layer structure of the repaired plate obtained in Examples 1 to 3 is a near single crystal structure grown along the
[001] direction. Figure 3 This is the grain orientation diagram of the repair interface of the repaired plate obtained in Example 1.
[0056] The repaired plates obtained in Comparative Examples 1 and 2 have a loose repair layer structure and obvious cracks at the repaired parts. The repaired plate obtained in Comparative Example 3 has a grain orientation in the repaired area that is very different from that of the substrate. It can be seen that the plasma treatment, inserted cladding thin plate laser cladding and water cooling steps are coordinated with each other, and the lack of any step will affect the repair effect.
Claims
1. A method for repairing cracks in a nickel-based single crystal alloy, characterized in that: include: The nickel-based single crystal alloy to be repaired is subjected to a decontamination treatment, wherein the nickel-based single crystal alloy comprises, by mass ratio, Cr: 6.0-8.0, Co: 6.0-8.0, W: 4.0-6.0, Al: 6.0-6.5, Ta: 6.0-7.0, Mo: 1.0-2.0, Re: 2.5-3.5, and Ni: 60-68; Crack extension treatment of decontaminated nickel-based single crystal alloy; preparing cladding powder and performing plasma treatment, and then pressing the cladding powder after the plasma treatment into a cladding sheet, wherein the cladding powder is GH4738 powder material; Inserting the cladding thin plate into the expanded crack to be repaired, and repairing the crack by using a laser cladding method; The cladding layer is cooled by water cooling.
2. The crack repair method of nickel-based single crystal alloy according to claim 1, characterized in that: The decontamination process is as follows: first, wash away the oil stains on the surface of the nickel-based single crystal alloy with alcohol, then use 280# and 400# sandpaper to grind away the oxide film on the surface of the nickel-based single crystal alloy, then wash with alcohol, and finally blow dry with a hair dryer.
3. The crack repair method of nickel-based single crystal alloy according to claim 1, characterized in that: The crack extension treatment method is as follows: a groove is set at the crack, and the groove shape is I-type.
4. The crack repair method of nickel-based single crystal alloy according to claim 1, characterized in that: The plasma treatment conditions are as follows: the power-on voltage is 40 to 60 V, the current is 1.6 to 2.0 A, and the power-on time is 6 to 10 min.
5. The crack repair method of nickel-based single crystal alloy according to claim 1, characterized in that: When pressing into cladding sheets, a binder is added to the cladding powder.
6. The crack repair method of nickel-based single crystal alloy according to claim 1, characterized in that: The method of laser cladding is as follows: argon gas is introduced for gas protection, and laser cladding is performed under the following parameter conditions: laser power 800-1400W, laser scanning speed 2-4mm / s, and laser spot size 2-3mm.
7. The crack repair method of nickel-based single crystal alloy according to claim 1, characterized in that: The method of cooling the cladding layer by water cooling is as follows: the cladding layer is circulated and cooled at a flow rate of 0.5 to 2 L / min.