A method for joining titanium aluminide to niobium using a titanium interlayer and the joint

Abstract

The application provides a method for connecting titanium aluminum carbide and niobium by adopting a titanium intermediate layer and a connected joint, and relates to the technical field of welding. The method comprises the following steps: S1, preparing a component to be connected; the component to be connected is formed by sequentially stacking titanium aluminum carbide base material, an intermediate layer and niobium base material from top to bottom, and the material of the intermediate layer is titanium; S2, performing discharge plasma sintering on the component to be connected under a preset air pressure to obtain a connected joint. By adopting the method, the cracking of the joint can be inhibited, the decarburization or Al evaporation of Ti3AlC2 at high temperature can be inhibited, thereby the deterioration of the base material is inhibited; the generation of brittle intermetallic compounds can be avoided, which is helpful to improve the interface bonding strength, thereby the strength of the connected joint is improved.

Description

Technical Field

[0001] This invention relates to the field of welding technology, and more specifically, to a method and joint for connecting titanium aluminum carbide and niobium using a titanium interlayer. Background Technology

[0002] Titanium aluminum carbide (Ti3AlC2) is a MAX phase material with both metallic and ceramic properties, possessing excellent mechanical properties, electrothermal conductivity, and thermal shock resistance, making it valuable for applications in aerospace, high-temperature structures, and other fields. Niobium (Nb) metal, as an important component of high-entropy alloys, superconducting materials, and high-temperature structural materials, is also in increasing demand in related fields due to its good high-temperature oxidation resistance and toughness. However, the connection between titanium aluminum carbide ceramic and niobium faces the following challenges: (1) The difference in thermal expansion coefficients between ceramic and metal leads to thermal stress during welding, resulting in joint cracking; (2) Ti3AlC2 is prone to decarburization and Al volatilization during welding, leading to deterioration of the base material; (3) The direct reaction between the two may generate brittle intermetallic compounds (Nb-Al compounds), severely weakening the mechanical properties of the joint (such as shear strength). Summary of the Invention

[0003] The problem solved by this invention is that the following problems exist in the connection process between titanium aluminum carbide ceramic and niobium: (1) the joint is prone to cracking; (2) decarburization and Al volatilization are prone to occur, leading to the deterioration of the base material; (3) brittle intermetallic compounds are prone to form, which seriously weakens the mechanical properties of the joint.

[0004] To address the above problems, this invention provides a method for connecting titanium aluminum carbide and niobium using a titanium interlayer, comprising:

[0005] Step S1: Prepare the component to be connected; the component to be connected is formed by stacking titanium aluminum carbide base material, intermediate layer and niobium base material from top to bottom, and the material of the intermediate layer is Ti;

[0006] Step S2: The components to be connected are subjected to discharge plasma sintering under a preset pressure to obtain a connection joint.

[0007] Optionally, in step S2, the temperature of the discharge plasma sintering is 900°C to 1200°C, the pressure is 5MPa to 30MPa, and the time is 5min to 30min.

[0008] Optionally, in step S2, the preset air pressure is lower than 0.008 Pa.

[0009] Optionally, the discharge plasma sintering temperature is 1000℃, the pressure is 20MPa, and the time is 20min.

[0010] Optionally, in step S1, the thickness of the intermediate layer is 50 μm to 200 μm.

[0011] Optionally, in step S1, the thickness of the titanium aluminum carbide substrate is 2 mm to 4 mm.

[0012] Optionally, in step S1, the thickness of the niobium base material is 2 mm to 4 mm.

[0013] Optionally, in step S1, the niobium parent material is made of pure niobium.

[0014] Optionally, in step S2, the spark plasma sintering is performed in a spark plasma sintering furnace.

[0015] The present invention also provides a connecting joint, which is made by means of connecting titanium aluminum carbide and niobium using a titanium interlayer as described above.

[0016] Compared with related technologies, this invention utilizes a titanium interlayer to connect titanium aluminum carbide and niobium. During the connection process, the titanium interlayer undergoes multi-stage reactions with the two parent materials (titanium aluminum carbide and niobium) to generate a multi-layer structure of Ti3AlC2 parent material / Ti3Al / TiAl layer / α-Ti single-phase layer / α-Ti and β-Ti lamellar mixed structure / Nb parent material. That is, a "gradual transition zone" is formed between Ti3AlC2 and Nb, which can reduce the thermal stress caused by the difference in thermal expansion coefficients, which is beneficial to suppressing crack formation and thus improving the overall toughness of the joint. Moreover, the TiAl and Ti3Al layers in the generated multi-layer structure indicate that Ti and Al react preferentially, avoiding the reaction of Nb and Al to form brittle intermetallic compounds (Nb-Al compounds), which helps to improve the interfacial bonding strength and thus improve the strength of the joint. Furthermore, during the joining process, due to the high reactivity and low melting point of titanium, the titanium interlayer preferentially participates in the reaction, absorbing heat and diffusing elements from Nb. This helps suppress the decarburization of Ti3AlC2 or Al evaporation at high temperatures, improves the shape retention of the ceramic phase, and inhibits the degradation of the base material, thereby ensuring the strength of the joint. Additionally, this invention employs spark plasma sintering to join the components. During the joining process, pulsed current excites the spark plasma, reducing the atomic diffusion free energy and increasing the diffusion rate, achieving a short-time, low-temperature welding process. Because the current is concentrated at the welding interface, the welding area can be locally heated, avoiding deformation and residual stress caused by large-area heating of the base material. Furthermore, the electromigration effect during spark plasma sintering accelerates interfacial atomic diffusion, which helps improve welding quality, resulting in a high-strength joint. In summary, the method of this invention can suppress joint cracking and inhibit the decarburization of Ti3AlC2 or Al evaporation at high temperatures, thereby inhibiting the degradation of the base material; it can also avoid the formation of brittle intermetallic compounds, helping to improve interfacial bonding strength, thus increasing the strength of the joint. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the method for connecting titanium aluminum carbide and niobium using a titanium interlayer in an embodiment of the present invention;

[0018] Figure 2 These are scanning electron microscope and energy dispersive spectroscopy (EDS) images of the connector prepared in Example 1.

[0019] Figure 3 The image shows a scanning electron microscope (SEM) image of the connector prepared in Comparative Example 1.

[0020] Figure 4 The image shows a scanning electron microscope (SEM) image of the connector prepared in Comparative Example 2.

[0021] Figure 5 This is a scanning electron microscope image of the connector prepared in Comparative Example 3. Detailed Implementation

[0022] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Although some embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the accompanying drawings and embodiments of the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0023] Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0024] The term "comprising" and its variations as used herein are open-ended, meaning "including but not limited to"; the term "based on" means "at least partially based on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments"; and the term "optionally" means "optional embodiments". Definitions of other terms will be given in the following description. It should be noted that the concepts of "first," "second," etc., mentioned in this invention are used to distinguish different objects, not to describe a specific order or hierarchy. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0025] like Figure 1 As shown in the figure, an embodiment of the present invention provides a method for connecting titanium aluminum carbide and niobium using a titanium interlayer, comprising:

[0026] Step S1: Prepare the component to be connected; the component to be connected is formed by stacking titanium aluminum carbide base material, intermediate layer and niobium base material from top to bottom, and the material of the intermediate layer is Ti;

[0027] Step S2: The components to be connected are subjected to discharge plasma sintering under a preset pressure to obtain a connection joint.

[0028] This invention utilizes a titanium interlayer to connect titanium aluminum carbide and niobium. During the connection process, the titanium interlayer undergoes multi-stage reactions with the two parent materials (titanium aluminum carbide and niobium) to generate a multi-layer structure consisting of Ti3AlC2 parent material / Ti3Al / TiAl layer / α-Ti single-phase layer / α-Ti and β-Ti lamellar mixed structure / Nb parent material. That is, a "gradual transition zone" is formed between Ti3AlC2 and Nb, which can reduce the thermal stress caused by the difference in thermal expansion coefficients, which is beneficial to suppressing crack formation and thus improving the overall toughness of the joint. Moreover, the TiAl and Ti3Al layers in the generated multi-layer structure indicate that Ti and Al react preferentially, avoiding the reaction of Nb and Al to form brittle intermetallic compounds (Nb-Al compounds), which helps to improve the interfacial bonding strength and thus improve the strength of the joint. Furthermore, during the joining process, due to the high reactivity and low melting point of titanium, the titanium interlayer preferentially participates in the reaction, absorbing heat and diffusing elements from Nb. This helps suppress the decarburization of Ti3AlC2 or Al evaporation at high temperatures, improves the shape retention of the ceramic phase, and inhibits the degradation of the base material, thereby ensuring the strength of the joint. Additionally, this invention employs spark plasma sintering to join the components. During the joining process, pulsed current excites the discharge plasma, reducing the atomic diffusion free energy and increasing the diffusion rate, achieving a short-time, low-temperature welding process. Because the current is concentrated at the welding interface, the welding area can be locally heated, avoiding deformation and residual stress caused by large-area heating of the base material. Furthermore, the electromigration effect during spark plasma sintering accelerates interfacial atomic diffusion, which helps improve welding quality, resulting in a high-strength joint. In summary, the method of this invention can suppress joint cracking and inhibit the decarburization of Ti3AlC2 or Al evaporation at high temperatures, thereby inhibiting the degradation of the base material; it can also avoid the formation of brittle intermetallic compounds, helping to improve interfacial bonding strength and thus increasing the strength of the joint.

[0029] In some embodiments of the present invention, in step S2, the preset gas pressure is lower than 0.008 Pa, the temperature of the spark plasma sintering is 900°C to 1200°C, the pressure is 5 MPa to 30 MPa, and the time is 5 min to 30 min. Preferably, the temperature of the spark plasma sintering is 1000°C, the pressure is 20 MPa, and the time is 20 min.

[0030] In some embodiments of the present invention, in step S1, the thickness of the intermediate layer is 50 μm to 200 μm, the thickness of the titanium aluminum carbide substrate is 2 mm to 4 mm, and the thickness of the niobium substrate is 2 mm to 4 mm.

[0031] In some embodiments of the present invention, in step S1, the niobium parent material is made of pure niobium.

[0032] In some embodiments of the present invention, in step S2, the discharge plasma sintering is performed in a discharge plasma sintering furnace.

[0033] This invention also provides a connecting joint, which is made using the method described above of connecting titanium aluminum carbide and niobium with a titanium interlayer.

[0034] The present invention will be further described below with reference to specific embodiments.

[0035] Example 1

[0036] A1. Preparation of the component to be connected; the component to be connected is formed by stacking titanium aluminum carbide base material, intermediate layer and niobium base material from top to bottom, the intermediate layer is made of Ti; wherein, the thickness of the intermediate layer is 100μm, the thickness of the titanium aluminum carbide base material is 3mm, and the thickness of the niobium base material is 3mm.

[0037] A2. In a spark plasma sintering furnace, the components to be connected are subjected to spark plasma sintering under a preset pressure to obtain a connection joint; the preset pressure is 0.006 Pa, the spark plasma sintering temperature is 1000℃, the pressure is 20 MPa, and the time is 20 min.

[0038] Example 2

[0039] A1. Preparation of the component to be connected; the component to be connected is formed by stacking titanium aluminum carbide base material, intermediate layer and niobium base material from top to bottom, the intermediate layer is made of Ti; wherein, the thickness of the intermediate layer is 50 μm, the thickness of the titanium aluminum carbide base material is 2 mm, and the thickness of the niobium base material is 2 mm.

[0040] A2. In a spark plasma sintering furnace, the components to be connected are subjected to spark plasma sintering under a preset pressure to obtain a connection joint; the preset pressure is 0.006 Pa, the spark plasma sintering temperature is 900℃, the pressure is 30 MPa, and the time is 30 min.

[0041] Example 3

[0042] A1. Preparation of the component to be connected; the component to be connected is formed by stacking titanium aluminum carbide base material, intermediate layer and niobium base material from top to bottom, the intermediate layer is made of Ti; wherein, the thickness of the intermediate layer is 200 μm, the thickness of the titanium aluminum carbide base material is 4 mm, and the thickness of the niobium base material is 4 mm.

[0043] A2. In a spark plasma sintering furnace, the components to be connected are subjected to spark plasma sintering under a preset pressure to obtain a connection joint; the preset pressure is 0.006 Pa, the temperature of the spark plasma sintering is 1200 °C, the pressure is 5 MPa, and the time is 5 min.

[0044] Comparative Example 1

[0045] The difference from Example 1 is that step A2 is: in a conventional heating diffusion furnace, the components to be connected are subjected to high-temperature diffusion welding under a preset gas pressure to obtain a connection joint; the preset gas pressure is 0.006 Pa, the temperature of the high-temperature diffusion welding is 1000 °C, the pressure is 20 MPa, and the time is 20 min.

[0046] Comparative Example 2

[0047] The difference from Example 1 is that in step A1, the material of the intermediate layer is Zr.

[0048] Comparative Example 3

[0049] The difference from Example 1 is that in step A1, the material of the intermediate layer is Nb.

[0050] Experimental Example

[0051] Scanning electron microscopy analysis was performed on the connectors prepared in Example 1 and Comparative Examples 1 to 3. The results are shown in the figure. Figures 2 to 5 ,from Figure 2 It can be seen that the joint prepared in Example 1 forms a multi-layer structure of Ti3AlC2 matrix / Ti3Al layer / TiAl layer / α-Ti single-phase layer / α-Ti and β-Ti lamellar mixed structure layer / Nb matrix. The thickness of the Ti3Al layer is approximately 1 μm, the TiAl layer is approximately 1 μm, the α-Ti layer is approximately 50 μm, and the α-Ti and β-Ti lamellar mixed structure layer is approximately 50 μm. Although the Ti3Al and TiAl layers are brittle layers, they are extremely thin. The stress transition between the α-Ti layer and the α-Ti and β-Ti lamellar mixed structure layer is relatively gentle, forming an ideal buffer zone (ductile transition zone). That is, a "gradual transition zone" is formed between Ti3AlC2 and Nb, which can reduce the thermal stress caused by the difference in thermal expansion coefficients, which is beneficial for suppressing crack formation and thus improving the overall toughness of the joint. Figure 2 It can be seen that the weld of the joint prepared in Example 1 is dense and without obvious defects. From Figure 3 It can be seen that the connector prepared in Comparative Example 1 has obvious cracks. From Figure 4 It can be seen that a joint with good metallurgical bonding was obtained in Comparative Example 2. From Figure 3 It can be seen that the connection joint prepared in Comparative Example 3 has obvious cracks.

[0052] It should be noted that, Figure 2 It was obtained through scanning electron microscopy and energy dispersive spectroscopy analysis. Figure 2From left to right, the layers are: Ti3AlC2 matrix, Ti3Al layer, TiAl layer, α-Ti single-phase layer, α-Ti and β-Ti lamellar mixed structure layer, and Nb matrix.

[0053] The results of shear strength testing of the joints prepared in Examples 1 to 3 and Comparative Examples 1 to 3 are shown in Table 1. As can be seen from Table 1, the joints prepared in Examples 1 to 3 have higher shear strength compared with Comparative Examples 1 to 3.

[0054] Table 1

[0055]

[0056] It should be noted that the joints prepared in Comparative Examples 1 and 3 had obvious cracks, resulting in low strength that could not be tested. In Table 1, the "-" indicates joints with low strength that could not be measured.

[0057] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the scope of protection of the present invention.

Claims

1. A method for connecting titanium aluminum carbide and niobium using a titanium interlayer, characterized in that, include: Step S1: Prepare the component to be connected; the component to be connected is formed by stacking titanium aluminum carbide base material, intermediate layer and niobium base material from top to bottom, and the material of the intermediate layer is Ti; Step S2: The components to be connected are subjected to discharge plasma sintering under a preset pressure to obtain a connection joint.

2. The method for connecting titanium aluminum carbide and niobium using a titanium interlayer according to claim 1, characterized in that, In step S2, the temperature of the discharge plasma sintering is 900°C to 1200°C, the pressure is 5MPa to 30MPa, and the time is 5min to 30min.

3. The method for connecting titanium aluminum carbide and niobium using a titanium interlayer according to claim 1, characterized in that, In step S2, the preset air pressure is lower than 0.008 Pa.

4. The method for connecting titanium aluminum carbide and niobium using a titanium interlayer according to claim 2, characterized in that, The discharge plasma sintering temperature is 1000℃, the pressure is 20MPa, and the time is 20min.

5. The method for connecting titanium aluminum carbide and niobium using a titanium interlayer according to claim 1, characterized in that, In step S1, the thickness of the intermediate layer is 50 μm to 200 μm.

6. The method for connecting titanium aluminum carbide and niobium using a titanium interlayer according to claim 1, characterized in that, In step S1, the thickness of the titanium aluminum carbide base material is 2mm to 4mm.

7. The method for connecting titanium aluminum carbide and niobium using a titanium interlayer according to claim 1, characterized in that, In step S1, the thickness of the niobium base material is 2 mm to 4 mm.

8. The method for connecting titanium aluminum carbide and niobium using a titanium interlayer according to claim 1, characterized in that, In step S1, the niobium base material is made of pure niobium.

9. The method for connecting titanium aluminum carbide and niobium using a titanium interlayer according to claim 1, characterized in that, In step S2, the discharge plasma sintering is carried out in a discharge plasma sintering furnace.

10. A connecting connector, characterized in that, It is manufactured using the method described in any one of claims 1 to 9, which uses a titanium interlayer to connect titanium aluminum carbide and niobium.

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