Method for connecting titanium aluminum carbide and niobium and connecting joint
Titanium aluminum carbide and niobium are connected at high temperature through spark plasma sintering to form a multilayer structure, which solves the problems of metallurgical compatibility and thermal expansion mismatch when connecting titanium aluminum carbide and niobium, improves the strength and toughness of the joint, and avoids the formation of brittle compounds.
Patent Information
- Application Number
- CN202510753970.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-06
- Publication Date
- 2025-09-05
AI Technical Summary
The existing technology for connecting titanium carbide aluminum and niobium has poor metallurgical compatibility and is prone to forming brittle Nb-Al intermetallic compounds, resulting in low joint strength. In addition, thermal expansion mismatch leads to large residual stress and easy cracking.
Spark plasma sintering is used to connect titanium aluminum carbide and niobium at 1200°C to 1500°C, with the heating and cooling rates controlled at above 50°C/min, to form a multilayer structure of Ti3AlC2 matrix/Ti2AlNb layer/AlNb2 layer/Al3Nb and AlNb3 mixed tissue layer/Nb matrix. Pulsed current is used to excite discharge plasma to accelerate atomic diffusion, achieving connection without an intermediate layer.
It significantly improves the thermal expansion mismatch and stress concentration problems, improves the overall toughness and strength of the connection joint, avoids the formation of brittle intermetallic compounds, and enhances the interface bonding strength.
Smart Images
Figure CN120590181A_ABST
Abstract
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 and a connection joint. Background Art
[0002] With the development of high-end manufacturing fields such as aerospace and nuclear energy equipment, higher requirements are placed on high-temperature structural materials. Especially in extreme service environments, materials not only need to have excellent mechanical properties and high-temperature oxidation resistance, but also need to meet the reliable connection performance between different materials. Titanium aluminum carbide (Ti3AlC2), as a representative of MAX phase ceramic materials, has the advantages of both metals and ceramics, such as high-temperature strength, good thermal conductivity, oxidation resistance and certain machinability. It shows broad application prospects in the fields of high-temperature components, hot end parts, etc. Niobium (Nb) is widely used in aircraft engines due to its excellent high-temperature strength, but its high density (8.6g / cm 3 ) has limited performance improvement. Connecting titanium carbide aluminum and niobium can combine the advantages of the two and is the key to achieving high-performance integrated components. However, this connection technology faces the following problems: (1) The metallurgical compatibility between the two is poor, and brittle Nb-Al intermetallic compounds are easily generated, resulting in low strength of the joint; (2) The thermal expansion mismatch between the two leads to large residual stress in the joint, which easily leads to joint cracking. In order to solve the above problems, traditional methods generally rely on intermediate layer (metal or alloy) transition connection, which not only increases the complexity of the process, but also introduces a new interface, which easily leads to stress concentration and strength reduction. It is difficult to achieve a good balance between strength and toughness in joint performance, especially under high temperature or impact load conditions, the joint is prone to failure. Therefore, how to solve the problems faced when connecting titanium carbide aluminum and niobium without introducing an intermediate layer has become a problem that needs to be solved urgently. Summary of the Invention
[0003] The problem to be solved by the present invention is how to solve the following problems in the connection process of titanium carbide aluminum ceramics and niobium without introducing an intermediate layer: (1) the poor metallurgical compatibility between the two, which easily generates brittle Nb-Al intermetallic compounds, resulting in low strength of the joint; (2) the mismatch in thermal expansion between the two leads to large residual stress in the joint, which easily causes cracking of the joint.
[0004] To solve the above problems, the present invention provides a method for connecting titanium carbide aluminum and niobium, comprising:
[0005] Step S1, splicing the titanium carbide aluminum base material and the niobium base material together to obtain a component to be connected;
[0006] Step S2: Under a preset gas pressure, the components to be connected are heated to a preset temperature at a preset heating rate for spark plasma sintering, and cooled to room temperature at a preset cooling rate to obtain a connection joint; wherein, the preset heating rate is above 50°C / min, the preset temperature is 1200°C to 1500°C, and the preset cooling rate is above 50°C / min.
[0007] Optionally, in step S2, the spark plasma sintering is performed at a pressure of 10 MPa to 30 MPa and for a time of 5 to 30 min.
[0008] Optionally, in step S2, the preset air pressure is lower than 0.008 Pa.
[0009] Optionally, in step S2, the preset heating rate is 100°C / min, the preset temperature is 1300°C, and the preset cooling rate is 100°C / min.
[0010] Optionally, in step S2, the spark plasma sintering is performed at a pressure of 20 MPa and for a time of 20 min.
[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 made by the above-mentioned method of connecting titanium carbide aluminum and niobium.
[0016] Compared with the related art, the present invention adopts spark plasma sintering to realize the connection between titanium carbide aluminum base material and niobium base material at a higher temperature (1200℃ to 1500℃), which can accelerate the reaction between Al and Nb, thereby quickly forming a strong metallurgical bond, and by controlling the heating rate and cooling rate during the connection process to a high level (above 50℃ / min), the decarburization of Ti3AlC2 and the desolvation of Al element are suppressed, thereby ensuring the stable existence of the ceramic phase, and finally realizing the connection between Ti3AlC2 ceramic and niobium without an intermediate layer; moreover, it has been found through experiments that during the connection process between titanium carbide aluminum base material and niobium base material, a Ti3AlC2 base material / Ti2AlNb layer is formed. / AlNb2 layer / Al3Nb and AlNb3 mixed tissue layer / Nb parent material multilayer structure, wherein the hardness of the Ti2AlNb layer is relatively low, the hardness of the AlNb2 layer located in the middle is relatively high, and the hardness of the Al3Nb and AlNb3 mixed tissue layer is relatively low. In this multilayer structure, the low hardness of Ti2AlNb on the Ti3AlC2 parent material side → the high hardness of the middle layer AlNb2 → the low hardness of Al3Nb and AlNb3 on the metal Nb end forms an "arched" hardness gradient, which significantly improves the thermal expansion mismatch and stress concentration problems between Nb and Ti3AlC2, is conducive to suppressing crack formation, thereby improving the overall toughness of the connection joint and avoiding cracking of the connection joint. In addition, the present invention adopts a spark plasma sintering method to realize the connection of the components to be connected. During the connection process, a pulse current is used to excite the discharge plasma, 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, avoiding deformation and residual stress caused by large-area heating of the parent material. In addition, the electromigration effect during spark plasma sintering accelerates interfacial atomic diffusion, which helps improve welding quality and thus form a stronger joint. In summary, the method of the present invention can not only inhibit cracking of the joint, but also avoid the formation of brittle intermetallic compounds (Nb-Al), helping to improve the interfacial bonding strength, thereby increasing the strength of the joint. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 Schematic diagram of the process of connecting titanium carbide aluminum and niobium in the implementation of the present invention;
[0018] Figure 2 This is a scanning electron microscope analysis image of the connection joint prepared in Example 1;
[0019] Figure 3 The scanning electron microscope analysis image of the connection joint prepared in Comparative Example 1;
[0020] Figure 4 This is a real picture of the connecting joint prepared in Comparative Example 3. DETAILED DESCRIPTION
[0021] 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.
[0022] 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.
[0023] 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.
[0024] like Figure 1 As shown, an embodiment of the present invention provides a method for connecting titanium carbide aluminum and niobium, comprising:
[0025] Step S1, splicing the titanium carbide aluminum base material and the niobium base material together to obtain a component to be connected;
[0026] Step S2: Under a preset gas pressure, the components to be connected are heated to a preset temperature at a preset heating rate for spark plasma sintering, and cooled to room temperature at a preset cooling rate to obtain a connection joint; wherein, the preset heating rate is above 50°C / min, the preset temperature is 1200°C to 1500°C, and the preset cooling rate is above 50°C / min.
[0027] Titanium aluminum carbide is a layered ceramic. At high temperatures, the Al element in it has high diffusivity and is prone to diffusion and desolvation. The Al element diffuses to the surface or adjacent materials. Specifically, Ti3AlC2 is prone to Al desolvation in a vacuum environment >1200℃.
[0028] In the embodiment of the present invention, spark plasma sintering is used to connect the titanium carbide aluminum base material and the niobium base material at a relatively high temperature (1200°C to 1500°C), which can accelerate the reaction between Al and Nb, thereby quickly forming a strong metallurgical bond. The heating rate and cooling rate during the connection process are controlled to be relatively high (above 50°C / min) to inhibit the decarburization of Ti3AlC2 and the desolvation of Al elements, thereby ensuring the stable existence of the ceramic phase and ultimately achieving a non-intermediate layer connection between Ti3AlC2 ceramic and niobium. Moreover, experiments have found that in the connection process between the titanium carbide aluminum base material and the niobium base material, a Ti3AlC2 base material / Ti2AlNb layer / Al2AlNb layer is formed. Nb2 layer / Al3Nb and AlNb3 mixed tissue layer / Nb parent material multilayer structure, wherein the hardness of the Ti2AlNb layer is low, the hardness of the AlNb2 layer in the middle is high, and the hardness of the Al3Nb and AlNb3 mixed tissue layer is low. In this multilayer structure, the low hardness of Ti2AlNb on the Ti3AlC2 parent material side → the high hardness of the middle layer AlNb2 → the low hardness of Al3Nb and AlNb3 on the metal Nb end, forming an "arched" hardness gradient, significantly improving the thermal expansion mismatch and stress concentration problems between Nb and Ti3AlC2, which is beneficial to suppress crack formation, thereby improving the overall toughness of the connection joint and avoiding cracking of the connection joint. In addition, the embodiment of 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, avoiding deformation and residual stress caused by large-area heating of the parent material. In addition, the electromigration effect during spark plasma sintering accelerates interfacial atomic diffusion, which helps improve welding quality and thus form a stronger joint. In summary, the method of the embodiment of the present invention can not only suppress cracking of the joint, but also avoid the formation of brittle intermetallic compounds (Nb-Al), which helps to improve the interface bonding strength, thereby improving the strength of the joint.
[0029] In some embodiments of the present invention, in step S2, the spark plasma sintering is performed at a pressure of 10 MPa to 30 MPa and for a time of 5 to 30 minutes.
[0030] In some embodiments of the present invention, in step S2, the preset air pressure is lower than 0.008 Pa.
[0031] In some embodiments of the present invention, in step S2, the preset heating rate is 100°C / min, the preset temperature is 1300°C, the preset cooling rate is 100°C / min, the spark plasma sintering pressure is 20 MPa, and the time is 20 minutes. The resulting joint has a higher shear strength.
[0032] In some embodiments of the present invention, in step S1, the thickness of the titanium-aluminum carbide parent material is 2 mm to 4 mm, the thickness of the niobium parent material is 2 mm to 4 mm, and the niobium parent material is made of pure niobium.
[0033] In some embodiments of the present invention, in step S2, the spark plasma sintering is performed in a spark plasma sintering furnace.
[0034] An embodiment of the present invention further provides a connecting joint, which is manufactured using the above-mentioned method for connecting titanium carbide aluminum and niobium.
[0035] The present invention is further described below with reference to specific embodiments.
[0036] Example 1
[0037] A1. Splice a titanium-aluminum carbide mother material and a niobium mother material together to obtain a component to be connected; the thickness of the titanium-aluminum carbide mother material is 3 mm, the thickness of the niobium mother material is 3 mm, and the niobium mother material is made of pure niobium.
[0038] A2. Place the components to be connected in a spark plasma sintering furnace, evacuate to a preset air pressure, heat the components to be connected to a preset temperature at a preset heating rate, perform spark plasma sintering, and cool to room temperature at a preset cooling rate to obtain a connection joint; wherein, the preset air pressure is 0.001 Pa, the preset heating rate is 100°C / min, the preset temperature is 1300°C, the preset cooling rate is 100°C / min, the spark plasma sintering pressure is 20 MPa, and the time is 20 min.
[0039] Example 2
[0040] A1. Splice a titanium-aluminum carbide mother material and a niobium mother material together to obtain a component to be connected; the thickness of the titanium-aluminum carbide mother material is 2 mm, the thickness of the niobium mother material is 2 mm, and the niobium mother material is made of pure niobium.
[0041] A2. Place the components to be connected in a spark plasma sintering furnace, evacuate to a preset air pressure, heat the components to be connected to a preset temperature at a preset heating rate, perform spark plasma sintering, and cool to room temperature at a preset cooling rate to obtain a connection joint; wherein, the preset air pressure is 0.001 Pa, the preset heating rate is 50°C / min, the preset temperature is 1200°C, the preset cooling rate is 50°C / min, the spark plasma sintering pressure is 30 MPa, and the time is 30 min.
[0042] Example 3
[0043] A1. Splice a titanium-aluminum carbide mother material and a niobium mother material together to obtain a component to be connected; the thickness of the titanium-aluminum carbide mother material is 4 mm, the thickness of the niobium mother material is 4 mm, and the niobium mother material is made of pure niobium.
[0044] A2. Place the components to be connected in a spark plasma sintering furnace, evacuate to a preset air pressure, heat the components to be connected to a preset temperature at a preset heating rate, perform spark plasma sintering, and cool to room temperature at a preset cooling rate to obtain a connection joint; wherein, the preset air pressure is 0.001 Pa, the preset heating rate is 150°C / min, the preset temperature is 1500°C, the preset cooling rate is 150°C / min, the spark plasma sintering pressure is 10 MPa, and the time is 5 min.
[0045] Comparative Example 1
[0046] The difference from Example 1 is that in step A2, the preset heating rate is 2°C / min, and the preset cooling rate is 20°C / min.
[0047] Comparative Example 2
[0048] The difference from Example 1 is that in step A2, the preset temperature is 1100° C. Experiments have shown that the connection joint prepared in Comparative Example 2 cannot form a good metallurgical bond and has obvious cracks.
[0049] Comparative Example 3
[0050] The difference from Example 1 is that in step A2, the preset temperature is 1600°C.
[0051] Comparative Example 4
[0052] The difference from Example 1 is that step A2 is: in a common heating diffusion furnace, the components to be connected are heated to a preset temperature at a preset heating rate for high-temperature diffusion welding, and then cooled to room temperature at a preset cooling rate to obtain a connection joint; wherein the preset gas pressure is 0.001Pa, the preset heating rate is 10°C / min, the preset temperature is 1300°C, the preset cooling rate is 10°C / min, the high-temperature diffusion welding pressure is 20MPa, and the time is 20min. Experimental results show that in Comparative Example 4, no metallurgical reaction occurs between the Ti3AlC2 base material and the Nb base material, and no connection joint can be obtained. It should be noted that during ordinary diffusion welding, the heating and cooling rate cannot reach 100°C / min, and can reach a maximum of 20°C / min.
[0053] Experimental example
[0054] The connection joints prepared in Example 1 and Comparative Example 1 were analyzed by scanning electron microscopy. Figures 2 to 3 ,from Figure 2 It can be seen that the connection joint prepared in Example 1 forms a multilayer structure of Ti3AlC2 base material / Ti2AlNb layer / AlNb2 layer / Al3Nb and AlNb3 mixed tissue layer / Nb base material, wherein the hardness of the Ti2AlNb layer is low, the hardness of the AlNb2 layer in the middle is high, and the hardness of the Al3Nb and AlNb3 mixed tissue layer is low. In this multilayer structure, the low hardness of Ti2AlNb on the Ti3AlC2 base material side → the high hardness of the middle layer AlNb2 → the low hardness of Al3Nb and AlNb3 on the metal Nb end forms an "arch-shaped" hardness gradient, which significantly improves the thermal expansion mismatch and stress concentration problems between Nb and Ti3AlC2, is beneficial to suppress crack formation, and thus improves 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 in the connection joint prepared in Comparative Example 1, a large amount of Al is removed from the Ti3AlC2 ceramic and reacts with Nb to form a thicker Nb-Al layer, resulting in a significant decrease in the shear strength of the joint.
[0055] The shear strength test was performed on the connection joints prepared in Examples 1 to 3 and Comparative Examples 1 to 4. The results are shown in Table 1. As can be seen from Table 1, the connection joints prepared in Examples 1 to 3 have higher shear strength than those in Comparative Examples 1 to 2 and Comparative Example 4. Compared with Examples 1 to 3, the connection joint prepared in Comparative Example 3 has higher shear strength. However, the actual shape observation of the connection joint sample prepared in Comparative Example 3 shows that the connection joint sample is smaller than the connection joint sample prepared in Comparative Example 3. Figure 4 ,from Figure 4 It can be seen that the connection joint prepared in Comparative Example 3 is too high in temperature, which causes the Ti3AlC2 ceramic and Nb to deform, affecting the normal use of the product.
[0056] Table 1
[0057]
[0058] It should be noted that the “-” connection joints in Table 1 represent low strength and cannot be measured.
[0059] 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 carbide aluminum and niobium, characterized in that: include: Step S1, splicing the titanium carbide aluminum base material and the niobium base material together to obtain a component to be connected; Step S2: Under a preset gas pressure, the components to be connected are heated to a preset temperature at a preset heating rate for spark plasma sintering, and cooled to room temperature at a preset cooling rate to obtain a connection joint; wherein, the preset heating rate is above 50°C / min, the preset temperature is 1200°C to 1500°C, and the preset cooling rate is above 50°C / min.
2. The method for connecting titanium carbide aluminum and niobium according to claim 1, characterized in that: In step S2, the spark plasma sintering is performed at a pressure of 10 MPa to 30 MPa and for a time of 5 to 30 minutes.
3. The method for connecting titanium aluminum carbide and niobium 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 carbide aluminum and niobium according to claim 1, characterized in that: In step S2, the preset heating rate is 100°C / min, the preset temperature is 1300°C, and the preset cooling rate is 100°C / min.
5. The method for connecting titanium aluminum carbide and niobium according to claim 2, characterized in that: In step S2, the spark plasma sintering is performed at a pressure of 20 MPa and for a time of 20 minutes.
6. The method for connecting titanium carbide aluminum and niobium 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 carbide aluminum and niobium 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 carbide aluminum and niobium 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 carbide aluminum and niobium 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 for connecting titanium carbide aluminum and niobium as claimed in any one of claims 1 to 9 is used for manufacturing the same.