Heterostructure nanocrystalline tantalum-tungsten alloy thin film and preparation method thereof

Abstract

The application discloses a heterostructure nanocrystalline tantalum-tungsten alloy film and a preparation method thereof. The method selects a tantalum-tungsten alloy prepared by electron beam vacuum melting as a target material, and uses a direct current magnetron sputtering method to prepare a heterostructure nanocrystalline tantalum-tungsten alloy film composed of small-grain-size columnar crystal structures close to a substrate and large-grain-size columnar crystal structures close to a surface on a substrate. The direct current magnetron sputtering method is adopted, the tantalum-tungsten alloy is selected as the target material, and the film structure is adjusted by regulating the direct current magnetron sputtering parameters including a sputtering power, a sputtering time and a substrate temperature, so that a bimodal heterostructure nanocrystalline tantalum-tungsten alloy film with mixed small-grain-size and large-grain-size columnar crystal structures is obtained, the hardness of the tantalum-tungsten alloy film is improved, and the tantalum-tungsten alloy film is suitable for fields such as a gun barrel coating and a cutter coating.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of metal alloy preparation, and particularly relates to a heterogeneous structure nanocrystalline tantalum-tungsten alloy film and a preparation method thereof. BACKGROUND

[0002] Tantalum and tantalum alloys have high melting point, low ductile-brittle transition temperature, good machinability, good corrosion resistance, high temperature strength and other attractive properties, and thus are highly concerned. These alloys have been widely used in electrolytic capacitors, chemical instruments, ballistic rockets and spacecraft. Tantalum has a body-centered cubic structure, and is different from other BCC structure metals in that it has an abnormally low Peierls lattice stress and a lower brittle-ductile transition temperature. Therefore, tantalum has good ductility at room temperature. However, the yield strength of tantalum at room temperature is relatively low, and an effective means for improving the hardness thereof is needed. Assuming that the Hall-Petch relationship is effective at the nanoscale, the yield strength of nanocrystalline tantalum with a grain size of 50 nm is about 6 GPa. Since the shear modulus G of Ta is 65 GPa, the theoretical shear strength is about G / 10, and thus the strength of nanocrystalline tantalum is close to its theoretical strength. It has been reported that the hardness of nanocrystalline films prepared by magnetron sputtering is one order of magnitude higher than the bulk hardness value. These studies confirm the effect of nanocrystallization on the improvement of the hardness of tantalum alloys.

[0003] There are many methods for preparing nanocrystals, such as electrodeposition, high-pressure torsion, laser cladding, magnetron sputtering and the like. Among these methods, magnetron sputtering has the advantages of high deposition rate, low substrate temperature, simple operation, controllable thickness and the like. Compared with homogeneous structure, heterogeneous structure can further improve the hardness and strength of the material. Generally, the preparation of a heterogeneous structure material needs to be continuously carried out in multiple steps, such as annealing treatment after large plastic deformation. However, these steps are relatively cumbersome, and the grain size is far beyond the nanoscale, and thus the strengthening effect of nanocrystallization cannot be achieved. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a preparation method of a heterogeneous structure nanocrystalline tantalum-tungsten alloy film in view of the above-mentioned deficiencies of the prior art. The present application uses a direct current magnetron sputtering method, selects tantalum-tungsten alloy as the target material, adjusts the film structure by adjusting the direct current magnetron sputtering parameters, obtains a bimodal heterogeneous structure nanocrystalline tantalum-tungsten alloy film with mixed columnar crystal structures of small grain size and large grain size, improves the hardness of the tantalum-tungsten alloy film, and has high preparation efficiency, thereby solving the problems of cumbersome conventional heterogeneous structure preparation process and grain size exceeding the nanoscale.

[0005] To solve the above technical problems, the technical scheme adopted by the present application is as follows: a preparation method of a heterostructure nanocrystalline tantalum-tungsten alloy thin film, characterized in that the method uses an electron beam vacuum melted tantalum-tungsten alloy as a target material, and uses a direct current magnetron sputtering method to prepare the heterostructure nanocrystalline tantalum-tungsten alloy thin film on a substrate; the mass percentage of each element in the tantalum-tungsten alloy target material is as follows: Ta 88% to 98%, and W 2% to 12%; the heterostructure nanocrystalline tantalum-tungsten alloy thin film is composed of small-grain-size columnar crystal structures close to the substrate and large-grain-size columnar crystal structures close to the surface.

[0006] The preparation method of the heterostructure nanocrystalline tantalum-tungsten alloy thin film is characterized in that the size of the tantalum-tungsten alloy target material is 60 mm x 5 mm in diameter x height, the substrate is a single-side polished Si sheet, and the substrate is cleaned in an ultrasonic cleaning machine for 30 min using acetone and ethanol and then vacuum dried. Generally, the present application uses wire cutting to process the electron beam vacuum melted tantalum-tungsten alloy into a circular target material that meets the size requirements of magnetron sputtering, and the target material is polished and polished before sputtering to ensure the purity of the tantalum-tungsten alloy thin film; the substrate is cleaned using acetone and ethanol before use to remove oil stains on the surface of the substrate and improve the film-substrate adhesion.

[0007] The preparation method of the heterostructure nanocrystalline tantalum-tungsten alloy thin film is characterized in that the specific steps of the preparation include:

[0008] Step one, install the tantalum-tungsten alloy target material on the target position of the magnetron sputtering equipment, adjust the distance between the tantalum-tungsten alloy target material and the substrate base surface to 65 mm, then open the mechanical pump, electromagnetic valve and molecular pump to vacuumize to 5 x 10 -4 Pa;

[0009] Step two, open the argon valve to introduce argon into the sputtering chamber, and use a gas flowmeter to adjust the argon flow to 30 sccm, then adjust the working gas pressure to 0.8 Pa by adjusting the shutter valve;

[0010] Step three, open the direct current sputtering power supply, adjust the sputtering power to 80 W, and pre-sputter the tantalum-tungsten alloy target material for 10 min; after the sputtering power stabilizes, open the shutter to sputter the substrate: first sputter for 30 min to 60 min at a sputtering power of 80 W to prepare small-grain-size columnar crystal structures, then increase the sputtering power to 100 W to 120 W, and open the substrate heating power supply to adjust the temperature to 300 ℃ for sputtering to prepare large-grain-size columnar crystal structures, and then take out the substrate after cooling to room temperature, to obtain a heterostructure nanocrystalline tantalum-tungsten alloy thin film on the substrate.

[0011] The application changes sputtering parameters in the sputtering process, uses small power and non-heated substrate process parameters to prepare small grain size columnar crystal structure at the beginning of sputtering, then controls the grain size by changing the sputtering power and heating the substrate to prepare large grain size columnar crystal structure, so that the thin film presents a heterogeneous grain structure.

[0012] The preparation method of the heterogeneous structure nanocrystalline tantalum-tungsten alloy thin film has the characteristics that the substrate self-rotation switch is turned on during the sputtering process in step three, and the cooling after sputtering is carried out in a vacuum environment. The substrate self-rotation switch is turned on during the sputtering process to ensure uniform sputtering.

[0013] The preparation method of the heterogeneous structure nanocrystalline tantalum-tungsten alloy thin film has the characteristics that the total sputtering time is maintained for 2h in step three, and the thickness of the heterogeneous structure nanocrystalline tantalum-tungsten alloy thin film is 3-5μm. The thickness of the heterogeneous structure nanocrystalline tantalum-tungsten alloy thin film is controlled by controlling the total sputtering time, and the surface of the thin film is relatively flat and dense, and the roughness is small.

[0014] The preparation method of the heterogeneous structure nanocrystalline tantalum-tungsten alloy thin film has the characteristics that the hardness value of the heterogeneous structure nanocrystalline tantalum-tungsten alloy thin film is 9.6-13.8GPa in step three. The hardness value of the heterogeneous structure nanocrystalline tantalum-tungsten alloy thin film prepared by the application is significantly higher than that of the traditional homogeneous structure nanocrystalline tantalum alloy.

[0015] In addition, the application also discloses a heterogeneous structure nanocrystalline tantalum-tungsten alloy thin film, which is prepared by the above method.

[0016] Compared with the prior art, the application has the following advantages:

[0017] 1. The application adopts a direct current magnetron sputtering method, selects tantalum-tungsten alloy as target material, adjusts the thin film structure by controlling the direct current magnetron sputtering parameters including sputtering power, sputtering time and substrate temperature, obtains a bimodal heterogeneous structure nanocrystalline tantalum-tungsten alloy thin film with mixed small grain size and large grain size columnar crystal structure, improves the hardness of the tantalum-tungsten alloy thin film, and the tantalum-tungsten alloy thin film is suitable for fields such as gun barrel coating and tool coating.

[0018] 2. The application adopts a direct current magnetron sputtering one-step method, and the heterogeneous structure nanocrystalline tantalum-tungsten alloy thin film can be obtained only by adjusting the direct current magnetron sputtering parameters, thereby saving the preparation cost and improving the preparation efficiency.

[0019] 3. The application directly controls the thin film structure by adjusting the direct current magnetron sputtering parameters, further increases the hardness value of the thin film under the strengthening condition of realizing structure nanocrystallization, and widens the application range of the tantalum-tungsten alloy thin film.

[0020] The technical solutions of the present application are described in further detail below with reference to the accompanying drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 Cross-sectional SEM image of the heterostructure nanocrystalline tantalum-tungsten alloy thin film prepared in Example 1 of the present application.

[0022] Figure 2 Surface SEM image of the heterostructure nanocrystalline tantalum-tungsten alloy thin film prepared in Example 1 of the present application.

[0023] Figure 3 Cross-sectional SEM image of the heterostructure nanocrystalline tantalum-tungsten alloy thin film prepared in Example 2 of the present application.

[0024] Figure 4 Surface SEM image of the heterostructure nanocrystalline tantalum-tungsten alloy thin film prepared in Example 2 of the present application.

[0025] Figure 5 Cross-sectional SEM image of the heterostructure nanocrystalline tantalum-tungsten alloy thin film prepared in Example 3 of the present application.

[0026] Figure 6 Surface SEM image of the heterostructure nanocrystalline tantalum-tungsten alloy thin film prepared in Example 3 of the present application.

[0027] Figure 7 Cross-sectional SEM image of the heterostructure nanocrystalline tantalum-tungsten alloy thin film prepared in Example 4 of the present application.

[0028] Figure 8 Surface SEM image of the heterostructure nanocrystalline tantalum-tungsten alloy thin film prepared in Example 4 of the present application.

[0029] Figure 9 Cross-sectional SEM image of the heterostructure nanocrystalline tantalum-tungsten alloy thin film prepared in Example 5 of the present application.

[0030] Figure 10 Surface SEM image of the heterostructure nanocrystalline tantalum-tungsten alloy thin film prepared in Example 5 of the present application.

[0031] Figure 11 Nanoin denter load-displacement (P-h) curve of the heterostructure nanocrystalline tantalum-tungsten alloy thin film prepared in Examples 1-3 of the present application.

[0032] Figure 12 Nanoin denter load-displacement (P-h) curve of the heterostructure nanocrystalline tantalum-tungsten alloy thin film prepared in Examples 4-5 of the present application.

[0033] Figure 13The nanoindentation hardness and modulus of the heterostructure nanocrystalline tantalum-tungsten alloy thin film prepared in the embodiment 1-5 of the present application are compared. DETAILED DESCRIPTION

[0034] The embodiments 1-5 of the present application all adopt a FJL-560a type multi-target magnetron sputtering device, the substrate can be heated, the power supply adopts a direct current power supply, and the maximum power can reach 500W.

[0035] Embodiment 1

[0036] The embodiment includes the following steps:

[0037] Step one, under the room temperature condition, the tantalum-tungsten alloy target material prepared by the electron beam vacuum melting and the Si substrate are put into the cavity of the magnetron sputtering device, the tantalum-tungsten alloy target material is installed on the target position of the magnetron sputtering device, the tantalum-tungsten alloy target material is kept vertically opposite to the Si substrate, the distance between the tantalum-tungsten alloy target material and the substrate base surface is adjusted to 65mm, then the mechanical pump, the electromagnetic valve and the molecular pump are opened to pump the sputtering chamber to the base vacuum of 5x10 -4 Pa;

[0038] The tantalum-tungsten alloy target material is obtained by the electric spark cutting, the size is 60mmx5mm, the mass percentage of each element is: Ta 88%, W 12%, and the surface treatment is carried out by using sandpaper before use to remove the cutting corrosion layer, the substrate is a single-side polished single crystal Si piece with a diameter of 2 inches, and the substrate is cleaned in the ultrasonic cleaning machine for 30min after using acetone and then vacuum dried before use;

[0039] Step two, the argon valve is opened to introduce argon into the sputtering chamber, and the argon flow is adjusted to 30sccm by using the gas flow meter, then the working gas pressure is adjusted to 0.8Pa by adjusting the shutter valve;

[0040] Step three, the direct current sputtering power supply is opened, the sputtering power is adjusted to 80W, the tantalum-tungsten alloy target material is pre-sputtered for 10min, the shutter is opened after the sputtering power is stable, the substrate self-rotation switch is turned on, and the substrate is sputtered: firstly, the small grain size columnar crystal structure is prepared by sputtering for 30min under the sputtering power of 80W, then the sputtering power is increased to 120W, the substrate heating power supply is turned on, the temperature is adjusted to 300℃, and the large grain size columnar crystal structure is prepared by sputtering for 90min, after the sputtering is completed, the vacuum environment in the sputtering cavity is kept until it is cooled to the room temperature, then it is taken out, and the heterostructure nanocrystalline tantalum-tungsten alloy thin film is obtained on the substrate.

[0041] Embodiment 2

[0042] The embodiment is different from embodiment 1 in that: in the sputtering process in step three, firstly, small-grain-size columnar crystal structure is prepared by sputtering for 45 min under a sputtering power of 80 W, then the sputtering power is increased to 100 W, and the temperature is adjusted to 300 DEG C by turning on the substrate heating power to prepare large-grain-size columnar crystal structure by sputtering for 75 min.

[0043] Embodiment 3

[0044] The embodiment is different from embodiment 1 in that: in the sputtering process in step three, firstly, small-grain-size columnar crystal structure is prepared by sputtering for 60 min under a sputtering power of 80 W, then the sputtering power is increased to 100 W, and the temperature is adjusted to 300 DEG C by turning on the substrate heating power to prepare large-grain-size columnar crystal structure by sputtering for 60 min.

[0045] Embodiment 4

[0046] The embodiment is different from embodiment 1 in that: in step one, the mass percentage of each element in the tantalum-tungsten alloy target material is: Ta 98%, W 2%; in the sputtering process in step three, firstly, small-grain-size columnar crystal structure is prepared by sputtering for 20 min under a sputtering power of 80 W, then the sputtering power is increased to 100 W, and the temperature is adjusted to 300 DEG C by turning on the substrate heating power to prepare large-grain-size columnar crystal structure by sputtering for 90 min.

[0047] Embodiment 5

[0048] The embodiment is different from embodiment 4 in that: in the sputtering process in step three, firstly, small-grain-size columnar crystal structure is prepared by sputtering for 60 min under a sputtering power of 80 W, then the sputtering power is increased to 100 W, and the temperature is adjusted to 300 DEG C by turning on the substrate heating power to prepare large-grain-size columnar crystal structure by sputtering for 60 min.

[0049] The microstructure and performance of the heterostructure nanocrystalline tantalum-tungsten alloy thin film prepared in embodiments 1-5 are characterized, and the results are shown in Figures 1-13 .

[0050] Figure 1 and Figure 2 The cross-section and surface SEM images of the heterostructure nanocrystalline tantalum-tungsten alloy thin film prepared in embodiment 1 are shown in Figure 1 and Figure 2It can be seen that the cross section of the tantalum-tungsten alloy thin film presents a heterogeneous columnar crystal structure, the overall thickness of the thin film is about 3.74 μm, and the fine grain and coarse grain double-peak heterogeneous structure is obviously presented, the grain size on the side close to the substrate is relatively fine, and the columnar crystals are closely combined, and the thickness of the layer is about 200 nm; after the sputtering power is increased from 80 W to 100 W and the substrate temperature is increased, the cross section of the thin film presents a coarse columnar crystal structure, the density between the large grains is less than that between the small grains, the grains are vertically arranged along the growth direction until the surface of the thin film, and the surface morphology presents a larger spherical cluster formed by the aggregation of nano clusters, and there are small gaps between the large clusters, corresponding to the pores between the coarse columnar crystals in the cross section.

[0051] Figure 3 and Figure 4 The cross section and surface SEM images of the heterogeneous structure nanocrystalline tantalum-tungsten alloy thin film prepared in Example 2 of the present application are shown in Figures 2a and 2b, respectively. Figure 3 and Figure 4 It can be seen that, similar to Example 1, the cross section of the tantalum-tungsten alloy thin film also presents a heterogeneous structure combined with fine grain columnar crystals and coarse grain columnar crystals, the overall thickness of the thin film is about 3.74 μm, and the thickness of the small grain layer is obviously increased due to the extension of the sputtering time at 80 W, and is about 920 nm, and the grain size of the large grains is smaller than that of the large grains in the thin film of Example 1, and the density is higher, and it can be seen from the surface morphology that the thin film of Example 1 is more flat and dense than that of Example 1, and the size of the cluster is smaller than that of the thin film of Example 1.

[0052] Figure 5 and Figure 6 The cross section and surface SEM images of the heterogeneous structure nanocrystalline tantalum-tungsten alloy thin film prepared in Example 3 of the present application are shown in Figures 3a and 3b, respectively. Figure 5 and Figure 6 It can be seen that, similar to Examples 1 and 2, the tantalum-tungsten alloy thin film also presents a heterogeneous columnar crystal structure, the overall thickness of the thin film is about 3.8 μm, and the thickness of the small grain layer is about 1.2 μm, and it can be seen from the surface morphology that the surface density of the thin film of Example 3 is higher, and is more flat, and the pores between the large clusters are obviously smaller.

[0053] Figure 7 and Figure 8 The cross section and surface SEM images of the heterogeneous structure nanocrystalline tantalum-tungsten alloy thin film prepared in Example 4 of the present application are shown in Figures 4a and 4b, respectively. Figure 7 and Figure 8 It can be seen that, similar to Examples 1-3, the tantalum-tungsten alloy thin film also presents a heterogeneous columnar crystal structure, and the thickness of the thin film is about 3.5 μm, and the thickness of the small grain layer is thin due to the short sputtering time at low power, and is only 0.6 μm, and it can be seen from the surface morphology that the surface of the thin film of Example 4 also presents a large cluster morphology structure in which small grains are aggregated together.

[0054] Figure 9 and Figure 10 The cross-section and surface SEM images of the heterostructure nanocrystalline tantalum-tungsten alloy thin film prepared in Example 5 of the present application are shown in Figures 6 and 7, respectively, from which Figure 9 and Figure 10 It can be seen that the thickness of the thin film is about 4.2 μm, and since the alloy thin film is sputtered for a long time at low power, the thickness of the small-grain layer is thick, and the thickness of the small-grain layer and the large-grain layer is basically the same. From the surface morphology, it can be seen that since the high-temperature sputtering time is long, the large-cluster structure of the thin film of Example 5 is more coarse than that of Example 4.

[0055] Figure 11 and 12 The nanoindentation load-displacement (P-h) curves of the heterostructure nanocrystalline tantalum-tungsten alloy thin films prepared in Examples 1-3 and 4-5 of the present application are shown in Figure 8, from which Figure 11 It can be seen that at an indentation depth of 300 nm, the load value of the thin film prepared in Example 1 is the lowest, i.e. the hardness is the lowest, and the load value of the thin film prepared in Example 3 is the highest, meaning that the hardness value of the thin film is the highest. From Figure 12 It can be seen that the load value of Example 4 is lower than that of Example 5, meaning that the hardness value of Example 4 is lower than that of Example 5. Further combined with the cross-section images, it can be seen that under the condition of the same composition, the higher the thickness of the small-grain layer, the higher the hardness value of the thin film.

[0056] Figure 13 The comparison of the nanoindentation hardness and modulus of the heterostructure nanocrystalline tantalum-tungsten alloy thin films prepared in Examples 1-3 of the present application is shown in Figure 9, from which Figure 13 It can be seen that the hardness value of the thin film prepared in Example 1 is 10.5 GPa, the hardness value of the thin film prepared in Example 2 is 11.1 GPa, the hardness value of the thin film prepared in Example 3 is 13.8 GPa, the hardness value of the thin film prepared in Example 4 is 9.6 GPa, and the hardness value of the thin film prepared in Example 5 is 12.4 GPa. Combined with the SEM images of Figure 12 and Figures 1-10 It can be seen that when the thickness of the small-grain layer increases, the hardness value of the thin film is effectively improved, which is because the hardness of the material and the grain size conform to the Hall-Petch relationship; when the thickness of the small-grain layer increases, the overall grain size of the thin film decreases, and thus the hardness of the thin film increases.

[0057] In summary, the present application adopts a direct current magnetron sputtering method to prepare nanocrystalline tantalum-tungsten alloy films on a single crystal Si substrate, and the structure of the film is regulated by adjusting the sputtering parameters in the preparation process, i.e., sputtering power, sputtering time and substrate temperature, to obtain a bimodal heterogeneous columnar crystal structure combining a small-grain layer and a large-grain layer. By changing the sputtering parameters, the thickness of the small-grain layer and the large-grain layer is regulated, thereby improving the overall hardness value of the tantalum-tungsten alloy film, and the tantalum-tungsten alloy film is uniform in composition and smooth and dense in surface. Compared with other preparation methods of heterogeneous nanocrystals, the preparation method of the present application is simple in steps, convenient in operation and high in efficiency, and the heterogeneous nanostructure nanocrystalline tantalum-tungsten alloy film can be obtained by only one step of magnetron sputtering, thereby effectively improving the hardness of the tantalum-tungsten alloy film.

[0058] The above description is only a preferred embodiment of the present application, and does not limit the present application in any way. Any simple modification, change and equivalent change made to the above embodiment according to the technical essence of the present application are still within the protection scope of the technical solution of the present application.

Claims

1. A method for preparing a heterostructured nanocrystalline tantalum-tungsten alloy thin film, characterized in that, This method uses a tantalum-tungsten alloy prepared by electron beam vacuum melting as the target material, and uses DC magnetron sputtering to prepare a heterostructured nanocrystalline tantalum-tungsten alloy thin film on a substrate. The mass percentage of each element in the tantalum-tungsten alloy target material is: Ta 88%~98%, W 2%~12%. The heterostructured nanocrystalline tantalum-tungsten alloy thin film consists of a small-grained columnar crystal structure near the substrate and a large-grained columnar crystal structure near the surface. The specific preparation steps include: Step 1: Install the tantalum-tungsten alloy target on the target position of the magnetron sputtering equipment, and adjust the distance between the tantalum-tungsten alloy target and the substrate surface to 65mm. Then, turn on the mechanical pump, solenoid valve, and molecular pump to evacuate to 5×10⁻⁶ mm. -4 Pa; Step 2: Open the argon valve to introduce argon into the sputtering chamber, and use a gas flow meter to adjust the argon flow rate to 30 sccm. Then, adjust the working gas pressure to 0.8 Pa by adjusting the gate valve. Step 3: Turn on the DC sputtering power and adjust the sputtering power to 80W. Pre-sputter the tantalum-tungsten alloy target for 10 minutes. After the sputtering power stabilizes, open the baffle to sputter the substrate: First, sputter at 80W for 30-60 minutes to prepare a small-grain-size columnar crystal structure. Then, increase the sputtering power to 100W-120W and turn on the substrate heating power to adjust the temperature to 300℃ to prepare a large-grain-size columnar crystal structure. After cooling to room temperature, remove the substrate to obtain a heterostructured nanocrystalline tantalum-tungsten alloy thin film on the substrate. Maintain the total sputtering time for 2 hours. The thickness of the heterostructured nanocrystalline tantalum-tungsten alloy thin film is 3μm-5μm.

2. The method for preparing a heterostructured nanocrystalline tantalum-tungsten alloy thin film according to claim 1, characterized in that, The tantalum-tungsten alloy target has a diameter × height of 60mm × 5mm. The substrate is a single-sided polished Si wafer, which is cleaned in an ultrasonic cleaner with acetone and ethanol for 30 minutes and then vacuum dried.

3. The method for preparing a heterostructured nanocrystalline tantalum-tungsten alloy thin film according to claim 1, characterized in that, In step three, the substrate rotation switch is turned on during the sputtering process, and the cooling after sputtering is carried out in a vacuum environment.

4. The method for preparing a heterostructured nanocrystalline tantalum-tungsten alloy thin film according to claim 1, characterized in that, The hardness value of the heterostructured nanocrystalline tantalum-tungsten alloy thin film described in step three is 9.6 GPa to 13.8 GPa.

5. A heterostructured nanocrystalline tantalum-tungsten alloy thin film, characterized in that, Prepared by the method described in any one of claims 1 to 4.

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