A method for improving diffusion welding of TiAl 45XD and GH4169 by adding a Ni foil interlayer

Abstract

The application discloses a TiAl 45XD and GH4169 alloy joint method, comprising the following steps of: sandpaper polishing, mechanical polishing, alcohol ultrasonic cleaning of the to-be-welded end faces of TiAl 45XD and nickel-based alloy; and adding a Ni foil intermediate layer. The center contact is placed in a vacuum hot-pressing sintering furnace; vacuumizing is carried out, the temperature is raised to 450 DEG C to 650 DEG C at a temperature raising rate of 8 to 10 DEG C / min, then the temperature is continuously raised to 900 DEG C, the pressurizing operation is started, the pressurizing rate is 1 to 5 MPa / min, the pressurizing is stopped after 10 to 30 min, the pressure is 39.2 MPa, and the temperature and pressure are kept for 60 min; final processing, and polishing and cleaning of the obtained TiAl 45XD and nickel-based alloy components. The application obtains a welded joint with certain strength, and has the advantages of small deformation, relatively dense combination and the like.

Description

Technical Field

[0001] This invention relates to a method for diffusion welding of TiAl 45XD modified with a Ni foil interlayer to a nickel-based alloy, and particularly to a method for manufacturing a diffusion weld joint of TiAl 45XD and a nickel-based alloy. Background Technology

[0002] GH4169 alloy is a widely used high-temperature alloy with good high-temperature strength, excellent fatigue resistance, and creep resistance. However, its high density reduces the thrust-to-weight ratio of aircraft and lowers fuel economy. TiAl 45XD is an excellent high-temperature structural material with good high-temperature strength, oxidation resistance, and creep resistance, comparable to nickel-based high-temperature alloys, and its density is only half that of GH4169. However, due to the poor room-temperature plasticity of titanium-aluminum alloys, they are difficult to process into large-sized parts. Therefore, joining TiAl 45XD and GH4169 alloys has become a practical necessity. Due to the differences in their physicochemical properties, the residual stress during fusion welding is high, making cracking likely. Diffusion welding is a solid-state welding technique that uses specific temperature and external pressure conditions to induce minute plastic deformation at the contact surface of two workpieces, thereby promoting atomic diffusion and achieving welding. Ni foil is a widely used interlayer material that can effectively reduce the stress between the two base materials and reduce cracking to a certain extent. It has the same main element as GH4169 alloy.

[0003] Therefore, there is a need for a method to incorporate a nickel-based alloy and TiAl45XD with a Ni foil interlayer to reduce residual stress and improve welding quality. Summary of the Invention

[0004] According to one aspect of this disclosure, a method for diffusion welding TiAl 45XD to a nickel-based alloy is provided, comprising the following steps: Step 1: Material preparation and surface treatment. Grind the end faces of the TiAl 45XD and the nickel-based alloy to be welded, then polish until the surface is free of scratches. Clean the end faces with alcohol using ultrasound and then dry. Step 2: Sample placement. Place the TiAl 45XD and the nickel-based alloy into a Ni foil interlayer (30μm thick) and center them in a hot-pressing sintering furnace. Step 3: After evacuating the hot-pressing sintering furnace, begin heating. Initiate vacuum diffusion welding, heating at a rate of 8-10℃ / min to 450℃-650℃ and holding for 30-40 min, then continuing to heat to 900℃ and holding for 10-30 min. Step 4: Heating and pressurizing. When the temperature reaches 900℃, begin pressurizing at a rate of 1-5MPa / min, stopping after 10-30 min. The pressure is 39.2MPa. Continue holding at this temperature and pressure for 60 min. Step 5: Final treatment. After stopping heating, allow the pressure to drop naturally. Perform final treatment on the obtained vacuum diffusion welded TiAl... The surfaces of 45XD and nickel-based alloy components are polished and cleaned.

[0005] Preferably, in step 1, different grades of sandpaper are used to polish the end faces of the TiAl 45XD and the nickel-based alloy to be welded.

[0006] Preferably, in step 3, the temperature is increased to 500℃~600℃ at a heating rate of 8~10℃ / min and held for 30~40min, and then increased to 850℃~900℃ at a heating rate of 8~10℃ / min and held for 10~25min.

[0007] Preferably, in the above steps, pressurization begins when the temperature reaches 900℃, at a rate of 2~3MPa / min, and stops after 10~25min, with a pressure of 39.2MPa, and the temperature and pressure are maintained for another 60min.

[0008] Preferably, during the vacuum diffusion welding process, the vacuum degree of the vacuum sintering furnace is ≤2×10⁻⁶. -2 Pa.

[0009] This invention uses a vacuum hot-press sintering furnace to perform diffusion bonding of TiAl 45XD and nickel-based alloys, resulting in a smooth matrix connection between the two materials and a joint with a certain welding strength. By utilizing the pressure and high temperature of the diffusion welding process, the microstructure of the welding interface can be easily and quickly adjusted, reducing brittle phases and giving the welded joint advantages such as small deformation and low stress, thus achieving an effective connection between TiAl 45XD and nickel-based alloys. Attached Figure Description

[0010] The above and other objects, features, and advantages of this disclosure will become more apparent from the more detailed description of the embodiments thereof in conjunction with the accompanying drawings. The drawings are provided to further illustrate the embodiments of this disclosure and form part of the specification. They are used together with the embodiments of this disclosure to explain the disclosure and do not constitute a limitation thereof. In the drawings, the same reference numerals generally represent the same components or steps.

[0011] Figure 1 The image shows a SEM image of a cross-section of a joint obtained by a method for manufacturing a TiAl 45XD and a nickel-based alloy joint by diffusion welding according to Embodiment 1 of this disclosure, wherein the upper side is the nickel-based alloy and the lower side is TiAl 45XD; Figure 2 The diagram shows the hardness distribution of the cross section of the joint obtained by the method of manufacturing a TiAl 45XD and nickel-based alloy joint by diffusion welding according to Embodiment 1 of this disclosure, from right to left, showing the transition from TiAl 45XD to nickel-based alloy. Detailed Implementation Hereinafter, exemplary embodiments according to the present disclosure will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present disclosure, and not all embodiments of the present disclosure, and it should be understood that the present disclosure is not limited to the exemplary embodiments described herein.

[0012] Example Example 1 Step 1: Material preparation and surface treatment Ingots with alloy composition Ti-45Al-2Nb-2Mn-1B and GH4169 were wire-cut to obtain cuboids with dimensions of 10mm×10mm×35mm and 5mm×10mm×35mm respectively. One end of each was selected as the welding end face. The welding end faces of the TiAl 45XD and nickel-based alloy cuboids were polished with different grades of sandpaper in turn. Then, they were polished until the surface was free of scratches. The end faces were ultrasonically cleaned with alcohol for 15 minutes and then dried. Step 2: The polished, cleaned, and dried TiAl 45XD was placed in a vacuum hot-pressing sintering furnace, aligned with a nickel-based alloy cuboid. Step 3: Heating Operation First, the vacuum hot sintering furnace is evacuated, and then the temperature is raised at a rate of 10℃ / min. The temperature is raised to 500℃ and held for 30 minutes. Then, the temperature is raised to 900℃ at a rate of 10℃ / min and held for 10 minutes. Step 4: Heating and pressurizing operation When the temperature reaches 900℃, the TiAl 45XD and nickel-based alloy cuboid are axially pressurized at a pressurization rate of 5MPa / min using a relevant mold. After 8 minutes, the pressure is stopped, reaching 39.2MPa. The pressure is held for 60 minutes while the temperature remains constant. Step 5: Final Processing After heating is stopped, the pressure drops naturally, and the surfaces of the obtained vacuum diffusion welded TiAl 45XD and nickel-based alloy components are polished and cleaned.

[0013] The obtained TiAl 45XD and nickel-based alloy joint was wire-cut to obtain a cross-section. After grinding and polishing the cross-section, the resulting SEM images and hardness distribution maps are shown below. Figure 1 , 2 As shown.

[0014] from Figure 1 As can be seen, the joint between TiAl 45XD and the nickel-based alloy obtained by this invention shows no obvious shrinkage cavities or porosity, the bond is relatively tight, and no welding cracks appear. The joint elements of TiAl 45XD with the nickel-based alloy and nickel foil diffuse, forming an intermediate phase layer of a certain thickness. Figure 2 This is a hardness distribution diagram of the cross-section of the diffusion weld joint of TiAl 45XD and a nickel-based alloy. From right to left, the hardness transitions from TiAl 45XD to the nickel-based alloy, decreasing in the middle. Figure 2 As can be seen, the joint hardness of TiAl45XD and nickel-based alloy obtained by this invention is lower than that of the base metal, reaching 300 HV. The deformation of the joint is within 2%, and the shear strength test shows that its average shear strength is 91.74 MPa.

[0015] The basic principles of this disclosure have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this disclosure are merely examples and not limitations, and should not be considered as essential features of each embodiment of this disclosure. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the scope of this disclosure to the necessity of employing the aforementioned specific details for implementation.

[0016] The block diagrams of devices, apparatuses, devices, and systems disclosed herein are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it. It should also be noted that in the apparatus, devices, and methods of this disclosure, the components or steps can be disassembled and / or recombined. These disassemblies and / or recombinations should be considered as equivalent solutions to this disclosure.

[0017] In this article, modifiers without quantifiers, such as "first" and "second," are intended to distinguish different components / parts / circuits / modules / devices / steps, rather than to emphasize order, positional relationship, importance, or priority. In contrast, modifiers with quantifiers, such as "first" and "second," can be used to emphasize the order, positional relationship, importance, or priority of different components / parts / circuits / modules / devices / steps.

[0018] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use this disclosure. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects without departing from the scope of this disclosure. Therefore, this disclosure is not intended to be limited to the aspects shown herein, but rather to be carried out within the widest scope consistent with the principles and novel features disclosed herein. The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of this disclosure to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

Claims

1. A method for diffusion welding TiAl 45XD to a nickel-based alloy, characterized in that, Includes the following steps: Step 1: Material preparation and surface treatment. Grind the end faces of the TiAl 45XD and the nickel-based alloy to be welded, then polish until the surface is free of scratches. Use organic solvent to ultrasonically clean the end faces to be welded and then dry them. Step 2: Place the sample. The TiAl 45XD and the nickel-based alloy are placed in the Ni foil interlayer (30μm) in a centered contact in a graphite mold in a vacuum hot pressing sintering furnace. Step 3: After evacuating the hot press furnace, heat it to 450℃~650℃ at a heating rate of 8~10℃ / min and hold for 30~40min. Then heat it to 900℃ and hold for 10~30min. Step 4: Heating and pressurizing operation. Start pressurizing when the temperature reaches 900℃ at a rate of 1~5MPa / min. Stop pressurizing after 10~30min and continue to maintain the temperature and pressure at 39.2MPa. Step 5: Final cleaning. After heating is stopped, the pressure drops naturally. The surfaces of the obtained vacuum diffusion welded TiAl 45XD and nickel-based alloy components are then polished and cleaned.

2. The method for diffusion welding TiAl 45XD to a nickel-based alloy according to claim 1, characterized in that, In step 1, different grades of sandpaper are used sequentially on the end faces of the TiAl 45XD and the nickel-based alloy to be welded.

3. The method for diffusion welding TiAl 45XD to a nickel-based alloy according to claim 1, characterized in that, In step 1, the organic solvent is alcohol. The ultrasonic cleaning of the end face lasts for 10-30 minutes.

4. The method for diffusion welding TiAl 45XD to a nickel-based alloy according to claim 1, characterized in that, In step 3, the temperature is increased to 500-600℃ at a heating rate of 8-10℃ / min and held for 30-40 minutes. Then, the temperature is increased to 900℃ at a heating rate of 8-10℃ / min and held for 10-30 minutes.

5. The method for diffusion welding TiAl 45XD to a nickel-based alloy according to claim 1, characterized in that, In step 4, pressurization begins when the temperature reaches 900℃ at a rate of 1~5MPa / min, and stops after 10~30min, with a pressure of 39.2MPa. The temperature and pressure are then maintained for another 60min.

6. The method for diffusion welding TiAl 45XD to a nickel-based alloy according to claim 1, characterized in that, During the vacuum diffusion welding process, the vacuum degree of the vacuum sintering furnace is ≤2×10⁻⁶. -2 Pa.

7. The method for diffusion welding TiAl 45XD to a nickel-based alloy according to claim 1, characterized in that, The elemental composition of the TiAl 45XD is Ti-45Al-2Nb-2Mn-1B, and the material grade of the nickel-based alloy is GH4169.

8. The method for diffusion welding TiAl 45XD to a nickel-based alloy according to claim 7, characterized in that, The TiAl 45XD has a machining size of 10mm×5mm×35mm, and the nickel-based alloy has a machining size of 5mm×5mm×35mm.

Images