Preparation method of tough-brittle combined Ti-15Mo / TiCrNb / TiAl3 layered composite board

Abstract

The invention discloses a preparation method of a tough-brittle combined Ti-15Mo / TiCrNb / TiAl3 layered composite plate. The preparation method comprises the following steps: 1, preparing a Ti-15Mo alloy plate, a Ti4Cr4Nb alloy foil and an aluminum foil raw material; 2, raw material surface treatment; 3, carrying out lamination design to obtain a laminated plate; 4, performing gradient vacuum hot pressing sintering to obtain a sintered plate blank; and 5, carrying out vacuum annealing treatment on the sintered plate blank to obtain the layered composite plate. The Ti4Cr4Nb alloy foil is adopted to isolate the Ti-15Mo alloy plate and the aluminum foil so as to ensure the plasticity and toughness of the Ti-15Mo alloy, a TiAl3 intermetallic compound is generated at the interface of Ti4Cr4Nb and the aluminum in situ by adopting a hot pressing sintering method, the microstructure is regulated and controlled by combining annealing, the tough-brittle combined Ti-15Mo / TiCrNb / TiAl3 layered composite plate is obtained, and the Ti-15Mo / TiCrNb / TiAl3 layered composite plate is suitable for the field of anti-impact protective materials.

Description

Technical Field

[0001] The present invention belongs to the technical field of titanium-aluminum composite materials, and specifically relates to a tough-brittle combination Ti-15Mo / TiCrNb / TiAl 3 A method for preparing a layered composite plate. Background Art

[0002] In recent years, the emergence of tough-brittle layered composite materials has opened up a new path for the research of impact-resistant protective materials. A new type of tough-brittle high-performance titanium / titanium aluminum (Ti / TiAl) light metal layered composite material has come into the sight of researchers. 3 Layered composites have received a lot of attention, but due to the 3 The plasticity and toughness are extremely low, and TiAl cannot be prepared by mechanical processing at this stage. 3 Alloy foil and Ti alloy are directly compounded, and the main method is to use Al and Ti foil to prepare layered composite plates by foil metallurgical composite method. Due to the intrinsic brittleness of intermetallic compounds, it is difficult to significantly improve the comprehensive mechanical properties of the material by relying solely on layered structure and limited improvement of the performance of TiAl intermetallic compounds. However, in order to further improve the performance of the material, it is planned to use Ti-15Mo alloy with better plasticity and toughness than Ti6Al4V (TC4) and TiAl intermetallic compounds to improve the comprehensive mechanical properties of the light metal composite material. Therefore, how to realize the composite of Ti-15Mo and TiAl intermetallic compounds and ensure the plasticity and toughness of Ti-15Mo and the formation of TiAl intermetallic compounds is a problem that researchers must solve. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a tough-brittle Ti-15Mo / TiCrNb / TiAl 3 The method uses Ti4Cr4Nb alloy foil to separate the Ti-15Mo alloy plate and the aluminum foil to ensure the plasticity and toughness of the Ti-15Mo alloy, and uses a hot pressing sintering method to generate TiAl in situ at the interface between Ti4Cr4Nb and aluminum. 3 Intermetallic compounds, combined with annealing treatment to regulate the microstructure, make the toughness of Ti-15Mo and the brittleness of TiAl 3 The intermetallic compounds combine to form a tough-brittle combination of Ti-15Mo / TiCrNb / TiAl 3 The layered composite plate solves the problem of existing tough-brittle laminated composite plates that both ensure the plasticity and toughness of Ti-15Mo and promote the formation of TiAl intermetallic compounds.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is: a tough-brittle combination of Ti-15Mo / TiCrNb / TiAl 3 The method for preparing a layered composite plate is characterized in that a Ti-15Mo alloy plate, a Ti4Cr4Nb alloy foil and an aluminum foil are laminated and composited, and then a hot pressing sintering composite method is used to prepare a Ti-15Mo / TiCrNb / TiAl 3 The layered composite board specifically comprises the following steps:

[0005] Step 1: preparing Ti-15Mo alloy plate, Ti4Cr4Nb alloy foil and aluminum foil;

[0006] Step 2: Surface treatment of the Ti-15Mo alloy plate, Ti4Cr4Nb alloy foil and aluminum foil prepared in step 1;

[0007] Step 3: Design a laminated plate by laminating the Ti-15Mo alloy plate, Ti4Cr4Nb alloy foil and aluminum foil after the surface treatment in step 2, and use the Ti4Cr4Nb alloy foil to isolate the Ti-15Mo alloy plate from direct contact with the aluminum foil to obtain a laminated plate;

[0008] Step 4: performing gradient vacuum hot pressing sintering on the laminated plate obtained in step 3 to obtain a sintered plate blank;

[0009] Step 5: vacuum anneal the sintered slab obtained in step 4 to obtain Ti-15Mo / TiCrNb / TiAl 3 Layered composite panels.

[0010] The above-mentioned ductile-brittle combination of Ti-15Mo / TiCrNb / TiAl 3 The method for preparing a layered composite plate is characterized in that the composition of the Ti-15Mo alloy plate is calculated by mass percentage as follows: Mo 15.8%, C 0.011%, Fe 0.01%, Si0.01%, O 0.099%, N 0.013%, and the balance is titanium. The main component of the Ti-15Mo alloy plate is the Mo element, and the [Mo] equivalent is 15 to 16, ensuring that its plastic deformation mechanism is mainly based on the twin induced plasticity (TWIP) effect, and at the same time, by strictly controlling the content of impurity elements, it is avoided that the elongation of the Ti-15Mo alloy plate is seriously reduced due to excessive impurity elements.

[0011] The above-mentioned ductile-brittle combination of Ti-15Mo / TiCrNb / TiAl 3The method for preparing a layered composite plate is characterized in that the composition of the Ti4Cr4Nb alloy foil is calculated by mass percentage as follows: Cr 4.16%, Fe 0.024%, Nb 7.50%, C 0.004%, O 0.043%, N 0.004%, and the balance is titanium. The composition of the Ti4Cr4Nb alloy foil is evolved from the Ti4822 alloy (γ-TiAl alloy), and the plasticity of the Ti4Cr4Nb alloy foil is ensured by removing the original Al element and strictly controlling the content of impurity elements.

[0012] The above-mentioned ductile-brittle combination of Ti-15Mo / TiCrNb / TiAl 3 The method for preparing a layered composite plate is characterized in that the structure of the laminated plate in step three is a bottom layer Ti-15Mo and M combination units Ti-15Mo / Ti4Cr4Nb / Al / Ti4Cr4Nb located on the bottom layer Ti-15Mo, M≥1, or a bottom layer Ti-15Mo, a top layer Ti-15Mo and N combination units Ti4Cr4Nb / Al / TiCrNb located between the bottom layer Ti-15Mo and the top layer Ti-15Mo, N≥1.

[0013] The above-mentioned ductile-brittle combination of Ti-15Mo / TiCrNb / TiAl 3 The method for preparing a layered composite plate is characterized in that the process of gradient vacuum hot pressing sintering in step 4 is: maintaining a vacuum degree of 1×10 -3 Pa~1×10 -5 Pa, first heat from room temperature to 520℃ and keep it for 2h, the sintering pressure is 8t, then heat to 650℃ and keep it for 6h, the sintering pressure is 20t, and then cool to room temperature with the furnace.

[0014] The present invention adopts a gradient vacuum hot pressing sintering process, firstly pre-sintering at 520℃ for 2h under low pressure, on the one hand, activates the atomic activity between the laminated plates to promote the interface reaction, on the other hand, releases the residual stress in the lamination process, and applies a sintering pressure of 8t to ensure the close bonding of the interface; then the sintering temperature is raised to a temperature close to the melting temperature of aluminum (650℃) and the pressure is increased to 20t, on the one hand, it is conducive to the reaction of Al and Ti4Cr4Nb to form interface TiAl 3 Intermetallic compounds avoid the leakage of molten aluminum during sintering, which reduces the risk of holes caused by the Kirkendall effect during the formation of intermetallic compounds and achieves the densification of intermetallic compounds.

[0015] The above-mentioned ductile-brittle combination of Ti-15Mo / TiCrNb / TiAl 3The method for preparing a layered composite plate is characterized in that the thickness of the intermetallic compound layer on the interface of the sintered plate blank in step 4 reaches more than 20 μm. By controlling the sintering time, the interface TiAl 3 The thickness of the intermetallic compound layer reaches more than 20 μm, thereby ensuring the dispersion of the high-speed impact stress on the intermetallic compound.

[0016] The above-mentioned ductile-brittle combination of Ti-15Mo / TiCrNb / TiAl 3 The method for preparing a layered composite plate is characterized in that the temperature of the vacuum annealing treatment in step 5 is 850°C, the holding time is 2h to 3h, the constant pressure is the contact pressure, and the air cooling is performed. The present invention controls the annealing at 850°C without changing the interface TiAl 3 The chemical composition of intermetallic compounds can also be used to study the chemical composition of Ti-15Mo / TiCrNb / TiAl 3 The Ti-15Mo phase composition and grain size in the layered composite plate are regulated. Usually, the vacuum annealing treatment makes the Ti-15Mo / TiCrNb / TiAl 3 The plasticity of the layered composite plate is increased to more than 38%.

[0017] The above-mentioned ductile-brittle combination of Ti-15Mo / TiCrNb / TiAl 3 The method for preparing a layered composite plate is characterized in that the Ti-15Mo / TiCrNb / TiAl 3 The Ti-15Mo grain size in the layered composite plate is 60 μm. By controlling the Ti-15Mo grain size, the TWIP effect of Ti15Mo is ensured, and its plasticity can be maintained above 35%, which is beneficial to improving the plasticity of the layered composite plate.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] 1. The present invention laminates Ti-15Mo alloy plate, Ti4Cr4Nb alloy foil and aluminum foil and then hot presses and sinters them. By adding Ti4Cr4Nb alloy foil as an intermediate layer to block the direct contact between the Ti-15Mo alloy plate and the aluminum foil, Al atoms are effectively prevented from diffusing into the Ti-15Mo alloy. Thus, the composite and hot press sintering process will not change the [Mo] equivalent of the Ti-15Mo alloy, effectively ensuring the intrinsic plastic toughness of the Ti-15Mo alloy. At the same time, TiAl intermetallic compound TiAl is generated in situ at the interface between the Ti4Cr4Nb alloy foil and the aluminum foil. 3 The ductility and toughness of Ti-15Mo alloy sheet and the brittleness and hardness of TiAl intermetallic compounds are used to form a tough-brittle combination of Ti-15Mo / TiCrNb / TiAl 3 Layered composite panels.

[0020] 2. The present invention regulates the microstructure including the phase composition and grain size of Ti-15Mo by vacuum annealing of the sintered slab, releases the phase transformation residual stress of the intermetallic compound layer without affecting the TiAl intermetallic compound and Ti4Cr4Nb, and further improves the Ti-15Mo / TiCrNb / TiAl 3 Plasticity of layered composite plates.

[0021] 3. The present invention forms different laminated structures by laminating Ti-15Mo alloy plate, Ti4Cr4Nb alloy foil and aluminum foil to obtain layered composite plates with different properties, thereby meeting the use requirements of different occasions.

[0022] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Ti-15Mo / TiCrNb / TiAl prepared in Example 1 of the present invention 3 SEM morphology of the layered composite plate.

[0024] Figure 2 Ti-15Mo / TiCrNb / TiAl prepared in Example 2 of the present invention 3 SEM morphology of the layered composite plate.

[0025] Figure 3 TiCrNb / TiAl prepared in Comparative Example 1 of the present invention 3 SEM morphology of the layered composite plate.

[0026] Figure 4 TiCrNb / TiAl prepared in Comparative Example 2 of the present invention 3 SEM morphology of the layered composite plate. DETAILED DESCRIPTION

[0027] Example 1

[0028] In this embodiment, Ti-15Mo alloy plate, Ti4Cr4Nb alloy foil and aluminum foil are laminated and then hot-pressed and sintered to prepare Ti-15Mo / TiCrNb / TiAl 3A layered composite plate, wherein the composition of the Ti-15Mo alloy plate is calculated by mass percentage as follows: Mo 15.8%, C 0.011%, Fe 0.01%, Si 0.01%, O 0.099%, N 0.013%, and the balance is titanium; and the composition of the Ti4Cr4Nb alloy foil is calculated by mass percentage as follows: Cr 4.16%, Fe 0.024%, Nb 7.50%, C 0.004%, O 0.043%, N 0.004%, and the balance is titanium;

[0029] The method specifically comprises the following steps:

[0030] Step 1: Prepare a Ti-15Mo alloy plate with a thickness of 1.5 mm, a Ti4Cr4Nb alloy foil with a thickness of 180 μm, and an aluminum foil with a thickness of 60 μm;

[0031] Step 2: Surface treatment is performed on the Ti-15Mo alloy plate, Ti4Cr4Nb alloy foil and aluminum foil prepared in step 1: firstly, the surface oxide film is removed by pickling, and then the foil is placed in an ethanol solution to prevent oxidation;

[0032] Step 3: Design a laminate of the Ti-15Mo alloy sheet, Ti4Cr4Nb alloy foil and aluminum foil after the surface treatment in step 2, and use the Ti4Cr4Nb alloy foil to isolate the Ti-15Mo alloy sheet from direct contact with the aluminum foil, so as to obtain a laminate with a total thickness of 11.1 mm; the structure of the laminate is a bottom layer Ti-15Mo and 5 combination units Ti-15Mo / Ti4Cr4Nb / Al / Ti4Cr4Nb located on the bottom layer Ti-15Mo;

[0033] Step 4: The laminated plate obtained in step 3 is subjected to gradient vacuum hot pressing sintering to obtain a sintered plate blank; the process of the gradient vacuum hot pressing sintering is: maintaining a vacuum degree of 1×10 -3 Pa~1×10 -5 Pa, firstly, the temperature is raised from room temperature to 520℃ and kept for 2h, the sintering pressure is 8t, then the temperature is raised to 650℃ and kept for 6h, the sintering pressure is 20t, and then the furnace is cooled to room temperature;

[0034] Step 5: vacuum anneal the sintered slab obtained in step 4 to obtain Ti-15Mo / TiCrNb / TiAl 3 The layered composite plate; the vacuum annealing treatment temperature is 850°C, the holding time is 2 hours, and it is air-cooled to room temperature, and the constant pressure is the contact pressure.

[0035] Example 2

[0036] The difference between this embodiment and embodiment 1 is that the structure of the laminate in step three is a bottom layer Ti-15Mo, a top layer Ti-15Mo and 15 combined units Ti4Cr4Nb / Al / Ti4Cr4Nb located between the bottom layer Ti-15Mo and the top layer Ti-15Mo, with a total thickness of 9.3 mm; the holding time for the vacuum annealing treatment in step five is 3 hours.

[0037] Comparative Example 1

[0038] The difference between this comparative example and Example 1 is that in step 3, Ti-15Mo alloy plate is not used for lamination design, and the structure of the laminated plate is 10 combined units Ti4Cr4Nb / Al / Ti4Cr4Nb, with a total thickness of 4.2 mm; the process of gradient vacuum hot pressing sintering in step 4 is: maintaining the vacuum degree of 1×10 -3 Pa~1×10 -5 Pa, firstly, the temperature was raised from room temperature to 520℃ and kept for 2h, the sintering pressure was 8t, then the temperature was raised to 650℃ and kept for 3h, the sintering pressure was 20t, and then air-cooled to room temperature, and the vacuum annealing treatment in step 5 was not performed, and the sintered slab was directly used as TiCrNb / TiAl 3 Layered composite panels.

[0039] Comparative Example 2

[0040] The difference between this comparative example and comparative example 1 is that the process of gradient vacuum hot pressing sintering in step 4 is: maintaining the vacuum degree at 1×10 -3 Pa~1×10 -5 Pa, first heat it from room temperature to 520℃ and keep it for 2h, the sintering pressure is 8t, then heat it to 650℃ and keep it for 6h, the sintering pressure is 20t, then heat it to 950℃ and keep it for 16h, the sintering pressure is 10t, and then air cool it to room temperature.

[0041] Figure 1 and Figure 2 Ti-15Mo / TiCrNb / TiAl prepared in Example 1 and Example 2 of the present invention respectively 3 SEM morphology of the layered composite plate, where Figure 1 Figure (a) is the SEM morphology of the Ti-15Mo / TiCrNb interface, Figure (b) is the SEM morphology of the Ti-15Mo layer, and Figure (c) is the SEM morphology of the composite plate. Figure 1 and Figure 2 It can be seen that the Ti-15Mo / TiCrNb / TiAl prepared by the present invention 3 The cross sections of the laminated plates are well bonded, and the aluminum in the laminate is completely consumed to form a dense TiAl 3intermetallic compound, and the thickness is 20μm, at the same time, Ti-15Mo / TiCrNb / TiAl 3 The Ti-15Mo layer in the layered composite plate is mainly β phase with a grain size of 60μm, and no obvious intermediate phase is formed at the interface between the Ti-15Mo and Ti4Cr4Nb layers.

[0042] The Ti-15Mo / TiCrNb / TiAl prepared in Example 1 and Example 2 of the present invention 3 The tensile properties of the Ti-15Mo layer in the layered composite plate were tested, and the results are shown in Table 1 below.

[0043] Table 1

[0044] sample <![CDATA[R m / MPa]]> <![CDATA[R p0.2 / MPa]]> A / ％ Example 1 795 532 39.5 Example 2 798 528 38.0

[0045] From Table 1, we can see that Ti-15Mo / TiCrNb / TiAl 3 The elongation after fracture of the Ti-15Mo layer in the layered composite plate reaches more than 38%, which meets the required characteristics of the toughness layer material and ensures its intrinsic plastic toughness.

[0046] Figure 3 TiCrNb / TiAl prepared in Comparative Example 1 of the present invention 3 SEM morphology of the layered composite plate. Figure 3 It can be seen that the TiCrNb / TiAl 3 No intermetallic compounds were formed in the layered composite plate, indicating that the hot pressing sintering time of 6 h is sufficient to ensure the effective consumption of the aluminum layer and the formation of TiAl 3 Necessary conditions for intermetallic compounds.

[0047] Figure 4 TiCrNb / TiAl prepared in Comparative Example 2 of the present invention 3 SEM morphology of the layered composite plate. Figure 4 It can be seen that the TiCrNb / TiAl 3 There is still no stable TiAl intermetallic compound at the interface of the layered composite plate, indicating that further increasing the gradient vacuum hot pressing sintering temperature will promote the TiAl 3 The layer undergoes phase transformation, TiAl 3 Forming a diffusion couple with Ti4Cr4Nb promotes TiAl 2 , γ-TiAl and other intermetallic compounds, which will reduce the interface density, increase interface defects and reduce the interface bonding strength.

[0048] The above is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent change made to the above embodiment according to the technical essence of the invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A method for preparing a tough-brittle Ti-15Mo / TiCrNb / TiAl3 layered composite plate, characterized in that: Ti-15Mo alloy sheet, Ti4Cr4Nb alloy foil and aluminum foil are laminated and then hot-pressed and sintered to prepare a Ti-15Mo / TiCrNb / TiAl3 layered composite plate, which specifically includes the following steps: Step 1: preparing Ti-15Mo alloy plate, Ti4Cr4Nb alloy foil and aluminum foil; Step 2: Surface treatment of the Ti-15Mo alloy plate, Ti4Cr4Nb alloy foil and aluminum foil prepared in step 1; Step 3: Design a laminated plate by laminating the Ti-15Mo alloy plate, Ti4Cr4Nb alloy foil and aluminum foil after the surface treatment in step 2, and use the Ti4Cr4Nb alloy foil to isolate the Ti-15Mo alloy plate from direct contact with the aluminum foil to obtain a laminated plate; Step 4: performing gradient vacuum hot pressing sintering on the laminated plate obtained in step 3 to obtain a sintered plate blank; Step 5: vacuum annealing the sintered slab obtained in step 4 to obtain a Ti-15Mo / TiCrNb / TiAl3 layered composite plate.

2. The method for preparing a tough-brittle Ti-15Mo / TiCrNb / TiAl3 layered composite plate according to claim 1, characterized in that: The components of the Ti-15Mo alloy plate are as follows by mass percentage: Mo 15.8%, C 0.011%, Fe 0.01%, Si 0.01%, O 0.099%, N 0.013%, and the balance is titanium.

3. The method for preparing a tough-brittle Ti-15Mo / TiCrNb / TiAl3 layered composite plate according to claim 1, characterized in that: The components of the Ti4Cr4Nb alloy foil are as follows by mass percentage: Cr 4.16%, Fe 0.024%, Nb 7.50%, C 0.004%, O 0.043%, N 0.004%, and the balance is titanium.

4. The method for preparing a tough-brittle Ti-15Mo / TiCrNb / TiAl3 layered composite plate according to claim 1, characterized in that: The structure of the laminated plate in step three is a bottom layer Ti-15Mo and M combination units Ti-15Mo / Ti4Cr4Nb / Al / Ti4Cr4Nb located on the bottom layer Ti-15Mo, M≥1, or a bottom layer Ti-15Mo, a top layer Ti-15Mo and N combination units Ti4Cr4Nb / Al / TiCrNb located between the bottom layer Ti-15Mo and the top layer Ti-15Mo, N≥1.

5. The method for preparing a tough-brittle Ti-15Mo / TiCrNb / TiAl3 layered composite plate according to claim 1, characterized in that: The process of gradient vacuum hot pressing sintering in step 4 is: maintain the vacuum degree at 1×10 -3 Pa~1×10 -5 Pa, first heat from room temperature to 520℃ and keep it for 2h, the sintering pressure is 8t, then heat to 650℃ and keep it for 6h, the sintering pressure is 20t, and then cool to room temperature with the furnace.

6. The method for preparing a tough-brittle Ti-15Mo / TiCrNb / TiAl3 layered composite plate according to claim 5, characterized in that: In step 4, the thickness of the intermetallic compound layer at the interface of the sintered slab reaches more than 20 μm.

7. The method for preparing a tough-brittle Ti-15Mo / TiCrNb / TiAl3 layered composite plate according to claim 1, characterized in that: The temperature of the vacuum annealing treatment in step 5 is 850° C., the holding time is 2 h to 3 h, the constant pressure is the contact pressure, and the process is air-cooled.

8. The method for preparing a tough-brittle Ti-15Mo / TiCrNb / TiAl3 layered composite plate according to claim 7, characterized in that: The Ti-15Mo grain size in the Ti-15Mo / TiCrNb / TiAl3 layered composite plate described in step five is 60 μm.

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