Method for connecting titanium aluminum carbide and niobium by adopting titanium intermediate layer and connecting joint

Abstract

The invention provides a method for connecting titanium aluminum carbide and niobium through a titanium intermediate layer and a connector, and relates to the technical field of welding. The method comprises the steps that S1, a to-be-connected assembly is prepared; the to-be-connected assembly is formed by sequentially stacking a titanium aluminum carbide base material, a middle layer and a niobium base material from top to bottom, and the middle layer is made of titanium; and S2, the to-be-connected assembly is subjected to spark plasma sintering under preset air pressure, and the connection joint is obtained. By adopting the method disclosed by the invention, joint cracking can be inhibited, and decarburization or Al evaporation of Ti3AlC2 at high temperature can be inhibited, so that deterioration of a base material is inhibited; and generation of brittle intermetallic compounds can be avoided, and the interface bonding strength can be improved, so that the strength of a connection joint is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of welding, and in particular to a method for connecting titanium carbide aluminum and niobium using a titanium intermediate layer and a connection joint. Background Art

[0002] Titanium aluminum carbide (Ti3AlC2) is a MAX phase material with dual properties of metal and ceramic. It has excellent mechanical properties, electrical and thermal conductivity, and thermal shock resistance, and has important application value 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 following challenges are faced in the process of joining titanium aluminum carbide ceramics and niobium: (1) The difference in thermal expansion coefficients between ceramics and metals leads to thermal stress during welding, which in turn causes cracking of the joint; (2) Ti3AlC2 is prone to decarburization and volatilization of Al elements during welding, resulting in degradation of the base material; (3) The direct reaction between the two may generate brittle intermetallic compounds (Nb-Al compounds), which seriously weaken the mechanical properties of the joint (such as shear strength). Summary of the Invention

[0003] The problem to be solved by the present invention is that the following problems exist during the connection process of titanium carbide aluminum ceramics and niobium: (1) the joint is prone to cracking; (2) decarburization and Al element volatilization are prone to occur, resulting in degradation of the parent material; and (3) brittle intermetallic compounds are easily generated, seriously weakening the mechanical properties of the joint.

[0004] To solve the above problems, the present invention provides a method for connecting titanium aluminum carbide and niobium using a titanium intermediate layer, comprising:

[0005] Step S1, preparing a component to be connected; the component to be connected is formed by stacking a titanium carbide aluminum base material, an intermediate layer and a niobium base material in sequence from top to bottom, wherein the intermediate layer is made of Ti;

[0006] Step S2: performing spark plasma sintering on the components to be connected under a preset pressure to obtain a connection joint.

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

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

[0009] Optionally, the spark plasma sintering is performed at a temperature of 1000° C., a pressure of 20 MPa, and a time of 20 min.

[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 carbide aluminum base material 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 base 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 manufactured by the above-mentioned method of connecting titanium carbide aluminum and niobium using a titanium intermediate layer.

[0016] Compared with the related art, the present invention uses a titanium intermediate layer to connect titanium aluminum carbide and niobium. During the connection process, the titanium intermediate layer will undergo multi-stage reactions with the parent materials on both sides (titanium aluminum carbide and niobium) to generate a Ti3AlC2 parent material / Ti3Al / TiAl layer / α-Ti single-phase layer / α-Ti and β-Ti lamellar mixed structure / Nb parent material multilayer structure, 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 coefficient, which is beneficial to inhibit crack formation, thereby improving the overall toughness of the joint; moreover, the TiAl and Ti3Al layers in the generated multilayer structure indicate that Ti and Al react preferentially, avoiding the reaction of Nb and Al to generate brittle intermetallic compounds (Nb-Al compounds), which helps to improve the interface bonding strength, thereby improving the strength of the connection joint. In addition, during the connection process, due to the high activity and low melting point of titanium, the titanium intermediate layer will preferentially participate in the reaction, absorb heat and the diffusing elements in Nb, which is beneficial to inhibiting the decarburization of Ti3AlC2 at high temperature or Al evaporation, improving the conformality of the ceramic phase, and inhibiting the degradation of the parent material, thereby helping to ensure the strength of the connection joint. In addition, the present invention adopts a spark plasma sintering method to achieve the connection of the components to be connected. During the connection process, the discharge plasma is excited by a pulse current, which reduces the atomic diffusion free energy, increases the diffusion rate, and realizes a short-time, low-temperature welding process. Since 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 parent material. In addition, the electromigration effect accelerates the diffusion of interface atoms during the spark plasma sintering process, which is beneficial to improving the welding quality, thereby forming a connection joint with higher strength. In summary, the method of the present invention can inhibit joint cracking, and can inhibit the decarburization or Al evaporation of Ti3AlC2 at high temperature, thereby inhibiting the degradation of the parent material; it can avoid the formation of brittle intermetallic compounds, which helps to improve the interface bonding strength, thereby improving the strength of the connection joint. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Schematic diagram of a process for connecting titanium carbide aluminum and niobium using a titanium intermediate layer in an embodiment of the present invention;

[0018] Figure 2 The scanning electron microscope and energy spectrum data analysis images of the connection joint prepared in Example 1;

[0019] Figure 3 This is a scanning electron microscope image of the connection joint prepared in Comparative Example 1;

[0020] Figure 4 This is a scanning electron microscope image of the connection joint prepared in Comparative Example 2;

[0021] Figure 5 This is a scanning electron microscope image of the connection joint prepared in Comparative Example 3. DETAILED DESCRIPTION

[0022] To make the above-mentioned objects, features, and advantages of the present invention more clearly understood, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings. Although certain embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as being limited to the embodiments described herein. Instead, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the 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 the present invention have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0024] The term "including" and its variations used in this document are open inclusions, that is, "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 other embodiment"; the term "some embodiments" means "at least some embodiments"; the term "optionally" means "optional embodiments". The relevant definitions of other terms will be given in the following description. It should be noted that the concepts of "first" and "second" mentioned in the present invention are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

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

[0026] Step S1, preparing a component to be connected; the component to be connected is formed by stacking a titanium carbide aluminum base material, an intermediate layer and a niobium base material in sequence from top to bottom, wherein the intermediate layer is made of Ti;

[0027] Step S2: performing spark plasma sintering on the components to be connected under a preset pressure to obtain a connection joint.

[0028] The embodiment of the present invention utilizes a titanium intermediate layer to connect titanium aluminum carbide and niobium. During the connection process, the titanium intermediate layer will undergo multi-stage reactions with the parent materials on both sides (titanium aluminum carbide and niobium) to generate a Ti3AlC2 parent material / Ti3Al / TiAl layer / α-Ti single-phase layer / α-Ti and β-Ti lamellar mixed structure / Nb parent material multilayer structure, 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 coefficient, and is beneficial to inhibiting crack formation, thereby improving the overall toughness of the joint; moreover, the TiAl and Ti3Al layers in the generated multilayer structure indicate that Ti and Al react preferentially, avoiding the reaction of Nb and Al to generate brittle intermetallic compounds (Nb-Al compounds), which helps to improve the interface bonding strength, thereby improving the strength of the connection joint. In addition, during the connection process, due to the high activity and low melting point of titanium, the titanium intermediate layer will preferentially participate in the reaction, absorb heat and the diffusing elements in Nb, which is beneficial to inhibiting the decarburization of Ti3AlC2 at high temperature or Al evaporation, improving the conformality of the ceramic phase, and inhibiting the degradation of the parent material, thereby helping to ensure the strength of the connection joint. In addition, the present invention adopts a spark plasma sintering method to achieve the connection of the components to be connected. During the connection process, the discharge plasma is excited by a pulse current to reduce the atomic diffusion free energy, increase the diffusion rate, and realize a short-time, low-temperature welding process. Since the current is concentrated at the welding interface, the welding area can be locally heated to avoid deformation and residual stress caused by large-area heating of the parent material. In addition, the electromigration effect in the spark plasma sintering process accelerates the diffusion of interface atoms, which is beneficial to improving the welding quality, thereby forming a connection joint with higher strength. In summary, the method of the embodiment of the present invention can inhibit joint cracking, and can inhibit the decarburization or Al evaporation of Ti3AlC2 at high temperature, thereby inhibiting the degradation of the parent material; it can avoid the formation of brittle intermetallic compounds, which helps to improve the interface bonding strength, thereby improving the strength of the connection joint.

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

[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 parent material is 2 mm to 4 mm, and the thickness of the niobium parent material is 2 mm to 4 mm.

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

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

[0033] An embodiment of the present invention further provides a connecting joint, which is manufactured by the above-mentioned method of connecting titanium aluminum carbide and niobium using a titanium intermediate layer.

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

[0035] Example 1

[0036] A1. Prepare the components to be connected; the components to be connected are composed of a titanium-aluminum carbide base material, an intermediate layer, and a niobium base material stacked in sequence from top to bottom, wherein the intermediate layer is made of Ti; wherein the thickness of the intermediate layer is 100 μm, the thickness of the titanium-aluminum carbide base material is 3 mm, and the thickness of the niobium base material is 3 mm.

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

[0038] Example 2

[0039] A1. Prepare the components to be connected; the components to be connected are composed of a titanium-aluminum carbide base material, an intermediate layer, and a niobium base material stacked in sequence from top to bottom, wherein 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 at a preset gas pressure to obtain a connection joint; the preset gas pressure is 0.006 Pa, the spark plasma sintering temperature is 900°C, the pressure is 30 MPa, and the time is 30 min.

[0041] Example 3

[0042] A1. Prepare the components to be connected; the components to be connected are composed of a titanium-aluminum carbide base material, an intermediate layer, and a niobium base material stacked in sequence from top to bottom, wherein 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 at a preset gas pressure to obtain a connection joint; the preset gas pressure is 0.006 Pa, the spark plasma sintering temperature is 1200°C, the pressure is 5 MPa, and the time is 5 minutes.

[0044] Comparative Example 1

[0045] The difference from Example 1 is that step A2 is: in an ordinary heating diffusion furnace, the components to be connected are subjected to high-temperature diffusion welding under a preset air pressure to obtain a connecting joint; the preset air 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 minutes.

[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] The connection joints prepared in Example 1 and Comparative Examples 1 to 3 were analyzed by scanning electron microscopy. Figures 2 to 5 ,from Figure 2 It can be seen that the connection joint prepared in Example 1 forms a multilayer structure of Ti3AlC2 base material / Ti3Al layer / TiAl layer / α-Ti single phase layer / α-Ti and β-Ti lamellar mixed tissue layer / Nb base material, wherein the thickness of the Ti3Al layer is about 1 μm, the thickness of the TiAl layer is about 1 μm, the thickness of the α-Ti layer is about 50 μm, and the thickness of the α-Ti and β-Ti lamellar mixed tissue layer is about 50 μm. Although the Ti3Al layer and the TiAl layer are brittle layers, they are extremely thin. The stress transition in the region from the α-Ti layer to the α-Ti and β-Ti lamellar mixed tissue layer is relatively slow, which is an ideal buffer zone (toughness 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 coefficient, which is beneficial to inhibit crack formation, thereby improving the overall toughness of the joint. Figure 2 It can be seen that the weld of the connection joint prepared in Example 1 is dense and has no obvious defects. Figure 3 It can be seen that the connection joint prepared in Comparative Example 1 has obvious cracks. Figure 4 It can be seen that a joint with good metallurgical bonding is obtained in Comparative Example 2. 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 by scanning electron microscopy and energy spectrum analysis. Figure 2From left to right in the figure are Ti3AlC2 base material, Ti3Al layer, TiAl layer, α-Ti single phase layer, α-Ti and β-Ti lamellar mixed structure layer, and Nb base material.

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

[0054] Table 1

[0055]

[0056] It should be noted that obvious cracks existed in the connection joints prepared in Comparative Examples 1 and 3, resulting in low strength of the connection joints and failure to perform testing. In Table 1, the connection joints marked with a "-" have low strength and cannot be measured.

[0057] Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. A method for connecting titanium aluminum carbide and niobium using a titanium intermediate layer, characterized in that: include: Step S1, preparing a component to be connected; the component to be connected is formed by stacking a titanium carbide aluminum base material, an intermediate layer and a niobium base material in sequence from top to bottom, wherein the intermediate layer is made of Ti; Step S2: performing spark plasma sintering on the components to be connected under a preset pressure to obtain a connection joint.

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

3. The method for connecting titanium aluminum carbide and niobium using a titanium intermediate layer 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 intermediate layer according to claim 2, characterized in that: The spark plasma sintering temperature is 1000° C., the pressure is 20 MPa, and the time is 20 min.

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

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

9. The method for connecting titanium aluminum carbide and niobium using a titanium intermediate layer according to claim 1, characterized in that: In the step S2, the spark plasma sintering is performed in a spark plasma sintering furnace.

10. A connecting joint, characterized in that: The method of connecting titanium carbide aluminum and niobium using a titanium intermediate layer as claimed in any one of claims 1 to 9 is adopted.

Images