CN114540766A - Nano-size metal W film/NiTi composite board and preparation method thereof - Google Patents

Abstract

The invention discloses a nano-sized metal W film/NiTi composite plate and a preparation method thereof, comprising a metal W film layer and a NiTi alloy layer, the chemical formula of the NiTi alloy layer is Ni _a Ti _50-a , 49.5≤a≤51.5. By combining the magnetron sputtering method and the high-temperature rolling method, the nano-sized W/NiTi multilayer films were sputtered on both sides of the mechanically polished NiTi alloy sheet, and then the NiTi sheets with multiple W/NiTi alloy multilayer films were sputtered. Stacked together, wrapped by a steel sleeve and then rolled at a high temperature, a metal W film/NiTi composite sheet is finally formed; in the composite sheet of the present invention, the nano-metal W film becomes a reinforcing phase in the composite material due to its ultra-high hardness, and its fracture strength is It is 1200 MPa, which is significantly larger than the NiTi sheet without nano-sized W (700 MPa). In addition, the preparation process of the present invention is simple and repeatable, and the operation is simple.

Description

A nano-sized metal W film/NiTi composite sheet and preparation method thereof

technical field

The invention belongs to the technical field of composite material preparation, and in particular relates to a nano-sized metal W film/NiTi composite plate, and also relates to a preparation method of the metal W film/NiTi composite plate.

Background technique

NiTi shape memory alloys are widely used in medical, mechanical and aerospace fields due to their shape memory effect and superelasticity. In recent years, with the lightweight development of various equipment and the requirements for service safety, NiTi shape memory alloys are required to have high strength. However, traditional NiTi shape memory alloys limit their applications due to their low strength. Compared with traditional grain refinement strengthening, precipitation strengthening and cold deformation strengthening, the strength of NiTi shape memory alloy can be significantly improved by introducing metal nanowires and nanoribbons as reinforcement phases. Among them, metal W nanowires and nanoribbons are important reinforcing phases due to their high strength. In recent years, there have been studies to obtain NiTi alloy and W nanowire composite wires through melting, forging and drawing processes. However, due to the high strength of metal W itself, it is difficult to further reduce the size of W nanowires through plastic deformation during the drawing deformation process (generally, the diameter of W nanowires is difficult to be less than 100 nm), so as to strengthen the NiTi wire to a greater extent. At the same time, the formation of W nanowires in composite materials in the past mainly relies on large deformation drawing technology, which limits the size of the obtained composite materials (composite material wires with a diameter of less than 0.5mm). Therefore, how to obtain large-sized NiTi/W composites and at the same time further reduce the size of W in the composites will further expand the application range of NiTi/W composites.

Compared with the traditional reduction of the size of metal W by plastic deformation, the magnetron sputtering method can gradually accumulate nano-sized W thin films from the atomic scale. However, on the one hand, the magnetron sputtering method itself has a low sputtering rate and can only obtain a W thin film with a thickness of tens of nanometers to several hundreds of nanometers; When the stress increases, when the thickness of the W film is greater than several hundred nanometers to several micrometers, the W film is prone to cracking. Therefore, it is difficult to obtain large-sized NiTi/W composites composed of nano-sized W thin films by the magnetron sputtering method.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a nano-sized metal W film/NiTi composite sheet, which solves the problem of low fracture strength of the existing metal composite sheet.

Another object of the present invention is to provide a method for preparing the above-mentioned metal W film/NiTi composite plate.

The technical scheme adopted in the present invention is that a nano-sized metal W film/NiTi composite plate includes a metal W film layer and a NiTi alloy layer, and the chemical formula of the NiTi alloy layer is Ni _a Ti _50-a , 49.5≤a≤51.5.

Another technical solution adopted in the present invention is, a preparation method of nano-sized metal W film/NiTi composite plate, which is specifically implemented according to the following steps:

In step 1, both sides of the NiTi alloy sheet are mechanically polished, and then the polished NiTi alloy sheet is ultrasonically cleaned with ethanol and acetone, then blown dry with nitrogen in a nitrogen spray gun, and placed in the base table of an ultra-high vacuum magnetron sputtering equipment superior;

Step 2, place the NiTi alloy target and the metal W target on the DC target stage in the magnetron sputtering apparatus, under the condition that the vacuum degree of the sputtering apparatus is 1.0×10 ^-5 to 4×10 ^-5 Pa , and then pass argon gas, adjust the vacuum degree of the vacuum chamber to 1 ~ 7Pa, then start to glow, and perform pre-sputtering;

Step 3: After the pre-sputtering is completed, the vacuum degree of the vacuum chamber is adjusted to 3-4Pa, and the NiTi alloy sheet is deposited alternately in the order of first depositing the NiTi alloy film and then depositing the W film, and the last layer is deposited NiTi alloy film, control The thickness of the W film and the NiTi film is the same, and finally the W/NiTi nano-multilayer film is deposited on both sides of the NiTi alloy sheet;

In step 4, a plurality of NiTi alloy plates deposited with W/NiTi nano-multilayer films are stacked together, then wrapped by a steel sleeve, and the steel sleeve is sealed by welding, and then the sealed steel sleeve is hot rolled, and finally The steel sleeve was removed to obtain a nano-sized metal W film/NiTi composite sheet.

The present invention is also characterized in that,

In step 1, the thickness of the NiTi alloy plate is 0.1-2 mm.

In step 2, the pre-sputtering time is 20min-60min.

In step 3, when depositing the NiTi alloy film, the sputtering power is 100-600W, and the sputtering rate is 20-60nm/min; when depositing the W film, the sputtering power is 100-600W, and the sputtering rate is 10-40nm/min.

In step 3, the thicknesses of the single-layer W film and the single-layer NiTi alloy film are both 5-150 nanometers; the total thickness of the W/NiTi nano-multilayer film is 200-5000 nanometers.

In step 4, during hot rolling, the starting rolling temperature is 700-900° C., the finishing rolling temperature is 900-1100° C., and the hot-rolling deformation amount is 30%-40%.

The beneficial effect of the present invention is that the present invention combines magnetron sputtering and lamination to prepare nano-sized metal W film/NiTi composite sheet for the first time, and it is found that its fracture strength is 1200 MPa, which is significantly larger than that of NiTi sheet without nano-sized W (700 MPa ). In addition, the preparation process of the present invention is simple and repeatable, the operation is simple, the size of the obtained NiTi/W sheet (reaching centimeters or even tens of centimeters) is large, and the size of W in the composite material is nanometer level (10-60 nanometers), It can be applied to driving devices in aerospace and biomedicine. It is also expected to provide design ideas for other metal nano-film and metal sheet composite materials, and provide theoretical guidance for the development of high-performance nano-sized metal film composite sheets.

Description of drawings

FIG. 1 is a flow chart of a method for preparing a metal W film/NiTi composite plate in Example 1 of the present invention.

2 is a macroscopic photograph of the nano-sized metal W film/NiTi composite plate provided in Example 1 of the present invention;

3 is a scanning electron microscope photograph of a cross-section in the thickness direction of the nano-sized metal W film/NiTi composite sheet provided in Example 1 of the present invention;

Fig. 4 is the scanning electron microscope photograph under the large magnification of the thickness direction cross section of the nano-sized metal W film/NiTi composite plate provided in Example 1 of the present invention;

5 is a stress-strain curve diagram of the nano-sized metal W film/NiTi composite sheet and the NiTi sheet without nano-sized W film provided in Example 1 of the present invention.

Detailed ways

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

The present invention is a nano-sized metal W film/NiTi composite plate, which includes a metal W film layer and a NiTi alloy layer. The chemical formula of the NiTi alloy layer is Ni _a Ti _50-a , 49.5≤a≤51.5, that is, in the NiTi alloy, Ni The atomic percent content is a%, and the atomic percent content of Ti is 50-a%.

More preferably, the chemical formula of the NiTi alloy layer in the nano-sized metal W/NiTi composite plate is Ni _a Ti _50-a , 50≤a≤51.

The preparation method of the nano-sized metal W film/NiTi composite plate of the present invention is specifically implemented according to the following steps:

In step 1, both sides of the NiTi alloy sheet are mechanically polished, and then the polished NiTi alloy sheet is ultrasonically cleaned with ethanol and acetone, then blown dry with nitrogen in a nitrogen spray gun, and placed in the base table of an ultra-high vacuum magnetron sputtering equipment superior;

The thickness of the NiTi alloy sheet is 0.1-2 mm;

Step 2, place the NiTi alloy target and the metal W target on the DC target stage in the magnetron sputtering apparatus, under the condition that the vacuum degree of the sputtering apparatus is 1.0×10 ^-5 to 4×10 ^-5 Pa , and then pass argon, adjust the vacuum degree of the vacuum chamber to 1 ~ 7Pa, then start to glow, carry out pre-sputtering, and the pre-sputtering time is 20min ~ 60min;

Step 3: After the pre-sputtering is completed, the vacuum degree of the vacuum chamber is adjusted to 3-4Pa, and the NiTi alloy sheet is deposited alternately in the order of first depositing the NiTi alloy film and then depositing the W film, and the last layer of the NiTi alloy film is deposited. Control the deposition time to control the thickness of the W film and the NiTi film to be the same, and finally deposit the W/NiTi nano-multilayer film on both sides of the NiTi alloy sheet;

When depositing NiTi alloy film, the sputtering power is 100-600W and the sputtering rate is 20-60nm/min;

When depositing W film, the sputtering power is 100-600W, and the sputtering rate is 10-40nm/min;

The thickness of the single-layer W film and the single-layer NiTi alloy film is 5-150 nanometers; the total thickness of the W/NiTi nano-multilayer film is 200-5000 nanometers;

More preferably, the thickness of the single-layer W film and the single-layer NiTi alloy film is 20-50 nanometers, and the total thickness of the W/NiTi nano-multilayer film is 500-2000 nanometers;

When depositing NiTi/W multilayer films on NiTi alloy sheets, the first layer is primed with NiTi film, in order to improve the bonding force with the substrate (NiTi plate), to avoid the separation of multilayer films from the substrate during rolling; the last layer The film also needs to deposit a NiTi film to cover the W film. On the one hand, it protects the lower W film. On the other hand, in order to prevent the nano W film from directly contacting the W film on the surface of the upper NiTi plate, the W film is prevented from breaking. The reason is that the nano metal W film The film itself has high strength, but the shape is poor, and the direct contact itself is easy to break, while the NiTi film can effectively protect the nano-W film due to the martensitic transformation;

The purpose of depositing a multi-layer film on the surface of the sheet is to maintain the nano-size of the W film itself, and at the same time, it can increase the content of the nano-sized W film in the final composite sheet; , but the content of W in the final composite material is too small, and it is difficult to strengthen the effect; for example, a 500nm W film can also be deposited, which satisfies the content in the final composite material, but it is still difficult to improve the strengthening effect without forming a small size (generally W The film size is less than 100nm to produce obvious strengthening effect);

In step 4, a plurality of NiTi alloy plates deposited with W/NiTi nano-multilayer films are stacked together, then wrapped by a steel sleeve, and the steel sleeve is sealed by welding, and then the sealed steel sleeve is hot rolled, and finally Remove the steel sleeve to obtain a nano-sized metal W film/NiTi composite sheet;

During hot rolling, the starting rolling temperature is 700-900 °C, the final rolling temperature is 900-1100 °C, and the hot rolling deformation is 30%-40%;

Further, the number of NiTi alloy sheets containing W/NiTi nano-multilayer film wrapped in the steel sleeve is 10; the final rolling temperature is 900°C, and the hot rolling deformation is controlled at 30%;

The selection of the final rolling temperature needs to be higher than the recrystallization temperature of the base plate, so that it is easy to plastically deform and facilitate rolling deformation. The rolling deformation of the sheet (the reduction rate of the total thickness) is less than 1/2-1/3 of the total thickness of the multilayer film; It will also deform along the length direction (rolling direction) of the sheet. When the rolling deformation of the overall sheet is too large (that is, the thickness reduction rate is too large, and the length direction is too elongated, the multilayer film on the surface of the NiTi sheet is completely Staggered or even broken in the middle (this is because the total thickness of the multilayer film is less than the thickness reduction rate of the overall sheet), so that the multilayer film or W film in the composite material of the final multilayer film and sheet is discontinuous and does not form a complete separation The interface is used to separate the NiTi plates on both sides, which is difficult to achieve a good enhancement effect.

The invention provides a method for preparing nano-sized metal W film/NiTi composite sheet by combining magnetron sputtering and hot rolling. The polished NiTi alloy sheet is sputtered to deposit nano-sized W/NiTi multilayer films on both sides, and then multiple NiTi sheets deposited with nano-sized W/NiTi alloy multilayer films are stacked together, wrapped in steel sleeves, and then rolled at high temperature. The metal W film/NiTi composite sheet is finally formed; in the composite sheet of the present invention, the nano metal W film becomes the reinforcing phase in the composite material due to its ultra-high hardness. The content of the W film, selected on the NiTi plate, indicates that the W film and the NiTi film are alternately deposited by magnetron sputtering, and the W film is separated by the NiTi film to maintain the nanometer size.

Example 1

The preparation method of the nano-sized metal W film/NiTi composite plate of the present invention, as shown in Figure 1, is specifically implemented according to the following steps:

Step 1, mechanically polish both sides of the NiTi alloy plate with a length, width and height of 80mm × 60mm × 0.5mm, ultrasonically clean the polished NiTi alloy plate with ethanol and acetone, and then dry it with nitrogen in a nitrogen spray gun, and put it in a superheater. On the base table of high vacuum magnetron sputtering equipment, wherein the chemical formula of the NiTi alloy plate is Ni ₅₀ Ti ₅₀ ;

In step 2, the NiTi alloy target (chemical formula is Ni ₅₀ Ti ₅₀ ) and the 99.999wt% metal W target are placed on the DC target stage in the magnetron sputtering apparatus, and the vacuum degree of the sputtering apparatus is 3.0×10 Under the condition of ^-5 Pa, argon gas was introduced again, and the vacuum degree of the vacuum chamber was adjusted to 3.5Pa, and then the ignition started, the ignition power was 400W, and the pre-sputtering was performed, and the pre-sputtering time was 45min;

Step 3: After the pre-sputtering is completed, the vacuum degree of the vacuum chamber is adjusted to 3Pa, and the NiTi alloy sheet is deposited alternately in the order of first depositing the NiTi alloy film and then depositing the W film, and the last layer of the NiTi alloy film is deposited by controlling the deposition. Time to control the thickness of the W film and the NiTi film to be the same, and finally the W/NiTi nano-multilayer film was deposited on both sides of the NiTi alloy sheet;

When depositing NiTi alloy film, the sputtering power is 350W and the sputtering rate is 40nm/min;

When depositing W film, the sputtering power is 400W and the sputtering rate is 10nm/min;

The thickness of single-layer W film and single-layer NiTi alloy film is 50 nanometers; the total thickness of W/NiTi nano-multilayer film is 2000 nanometers;

Step 4, stack 10 NiTi alloy plates on which the W/NiTi nano-multilayer film is deposited, then wrap them with a steel sleeve, and seal the steel sleeves by welding, and then hot-roll the sealed steel sleeves. Remove the steel sleeve to obtain a nano-sized metal W film/NiTi composite sheet;

During hot rolling, the starting rolling temperature was 800°C, the finishing rolling temperature was 900°C, and the hot rolling deformation amount was 30%.

Fig. 2 is a macro-morphological photograph of the nano-scale metal W film/NiTi composite sheet prepared by stacking and magnetron sputtering provided in Example 1, which shows that by the method provided by the present invention, 10 pieces of NiTi made of multilayer films are deposited The sheet forms a complete composite sheet after rolling with good interfacial bonding.

Figure 3 is a scanning electron microscope backscattered electron photo of the nano-scale metal W film/NiTi composite sheet prepared by stacking and magnetron sputtering provided in Example 1, wherein the white stripes are W nano-films, and the gray are NiTi plates, which shows that In the present invention, the NiTi plates of a plurality of magnetron sputtering W/NiTi multilayer films have good interface bonding after hot rolling deformation.

4 is a scanning electron microscope backscattered electron photo of the nano-scale W film at the interface of the nano-scale metal W film/NiTi composite sheet prepared by lamination and magnetron sputtering provided in Example 1 of the present invention, showing that the W film in the W/NiTi composite sheet has The thickness is about 50 nm, which is consistent with the design in the present invention.

Fig. 5 shows the stress-strain curve diagram of nano-scale metal W film/NiTi composite sheet prepared by stacking and magnetron sputtering provided in Example 1 of the present invention, and compared with pure NiTi sheet, the results show that nano-scale metal W/NiTi The fracture strength of the composite sheet is 1200MPa, and the fracture shape is 30%, which is better than that of the NiTi sheet.

Example 2

The preparation method of the nano-sized metal W film/NiTi composite plate of the present invention is specifically implemented according to the following steps:

In step 1, both sides of the NiTi alloy plate with a thickness of 0.5mm are mechanically polished, and then the polished NiTi alloy plate is ultrasonically cleaned with ethanol and acetone, and then dried with nitrogen in a nitrogen spray gun, and placed in an ultra-high vacuum magnetron On the substrate table of sputtering equipment;

Step 2, place the NiTi alloy target and the metal W target on the DC target stage in the magnetron sputtering apparatus, and then pass argon gas under the condition that the vacuum degree of the sputtering apparatus is 1.0×10 ^-5 a , adjust the vacuum degree of the vacuum chamber to 1Pa, then start to glow, carry out pre-sputtering, and the pre-sputtering time is 20min;

Step 3: After the pre-sputtering is completed, the vacuum degree of the vacuum chamber is adjusted to 4Pa, and the NiTi alloy sheet is deposited alternately in the order of first depositing the NiTi alloy film and then depositing the W film, and the last layer of the NiTi alloy film is deposited by controlling the deposition. Time to control the thickness of the W film and the NiTi film to be the same, and finally the W/NiTi nano-multilayer film was deposited on both sides of the NiTi alloy sheet;

When depositing NiTi alloy film, the sputtering power is 600W and the sputtering rate is 20nm/min;

When depositing W film, the sputtering power is 100W and the sputtering rate is 10nm/min;

The thickness of single-layer W film and single-layer NiTi alloy film is 100 nanometers; the total thickness of W/NiTi nano-multilayer film is 4000 nanometers;

Step 4, stack 15 NiTi alloy plates on which the W/NiTi nano-multilayer film is deposited, then wrap them with a steel sleeve, and seal the steel sleeves by welding, and then hot-roll the sealed steel sleeves. Remove the steel sleeve to obtain a nano-sized metal W film/NiTi composite sheet;

During hot rolling, the starting rolling temperature is 900 °C, the final rolling temperature is 1000 °C, and the hot rolling deformation is 35%; the starting material is easily deformed during rolling, so the temperature is lower. In the later stage, the material has accumulated plastic deformation, work hardening, and deformation is difficult, so the temperature of the subsequent rolling is higher, which is convenient for rolling deformation.

Example 3

The preparation method of the nano-sized metal W film/NiTi composite plate of the present invention is specifically implemented according to the following steps:

In step 1, both sides of the NiTi alloy sheet are mechanically polished, and then the polished NiTi alloy sheet is ultrasonically cleaned with ethanol and acetone, then blown dry with nitrogen in a nitrogen spray gun, and placed in the base table of an ultra-high vacuum magnetron sputtering equipment superior;

The thickness of the NiTi alloy sheet is 2 mm;

Step 2, place the NiTi alloy target and the metal W target on the DC target stage in the magnetron sputtering apparatus, and then pass argon gas under the condition that the vacuum degree of the sputtering apparatus is 4×10 ^-5 Pa , adjust the vacuum degree of the vacuum chamber to 7Pa, then start to glow, carry out pre-sputtering, and the pre-sputtering time is 50min;

Step 3: After the pre-sputtering is completed, the vacuum degree of the vacuum chamber is adjusted to 3Pa, and the NiTi alloy sheet is deposited alternately in the order of first depositing the NiTi alloy film and then depositing the W film, and the last layer of the NiTi alloy film is deposited by controlling the deposition. Time to control the thickness of the W film and the NiTi film to be the same, and finally the W/NiTi nano-multilayer film was deposited on both sides of the NiTi alloy sheet;

When depositing NiTi alloy film, the sputtering power is 500W and the sputtering rate is 30nm/min;

When depositing W film, the sputtering power is 400W and the sputtering rate is 30nm/min;

The thickness of the single-layer W film and the single-layer NiTi alloy film is 150 nanometers; the total thickness of the W/NiTi nano-multilayer film is 5000 nanometers;

Step 4, stack 20 NiTi alloy plates on which W/NiTi nano-multilayer films are deposited, then wrap them with a steel sleeve, and seal the steel sleeves by welding, and then hot-roll the sealed steel sleeves. Remove the steel sleeve to obtain a nano-sized metal W film/NiTi composite sheet;

During hot rolling, the starting rolling temperature was 950°C, the finishing rolling temperature was 1100°C, and the hot rolling deformation amount was 40%.

Claims (7)

1. A nanometer metal W film/NiTi composite board is characterized by comprising a metal W film layer and a NiTi alloy layer, wherein the chemical formula of the NiTi alloy layer is Ni_aTi_50-a，49.5≤a≤51.5。

2. A preparation method of a nano-sized metal W film/NiTi composite board is characterized by comprising the following steps:

step 1, mechanically polishing the two sides of a NiTi alloy plate, ultrasonically cleaning the polished NiTi alloy plate by using ethanol and acetone, blow-drying the NiTi alloy plate by using nitrogen in a nitrogen spray gun, and placing the NiTi alloy plate on a substrate table of ultrahigh vacuum magnetron sputtering equipment;

step 2, placing the NiTi alloy target and the metal W target on a direct current target table in a magnetron sputtering instrument, wherein the vacuum degree of the sputtering instrument is 1.0 multiplied by 10^-5～4×10^-5Pa conditionThen introducing argon, adjusting the vacuum degree of the vacuum chamber to 1-7 Pa, starting glow and carrying out pre-sputtering;

step 3, after the pre-sputtering is finished, regulating the vacuum degree of the vacuum chamber to 3-4 Pa, sequentially and alternately depositing a NiTi alloy film and a W film on the NiTi alloy plate according to the sequence of depositing the NiTi alloy film and then depositing the W film, depositing the NiTi alloy film on the last layer, controlling the thicknesses of the W film and the NiTi film to be the same, and finally depositing the W/NiTi nano multilayer film on both sides of the NiTi alloy plate;

and 4, stacking a plurality of NiTi alloy plates deposited with the W/NiTi nano multilayer film together, wrapping the plates by a steel sleeve, sealing the steel sleeve by welding, hot rolling the sealed steel sleeve, and finally removing the steel sleeve to obtain the nano-sized metal W film/NiTi composite plate.

3. The method as claimed in claim 2, wherein in step 1, the thickness of the NiTi alloy plate is 0.1-2 mm.

4. The method for preparing a nano-sized metal W film/NiTi composite board according to claim 2, wherein in the step 2, the pre-sputtering time is 20min to 60 min.

5. The method as claimed in claim 2, wherein in step 3, the sputtering power is 100-600W and the sputtering rate is 20-60nm/min during deposition of the NiTi alloy film; when the W film is deposited, the sputtering power is 100-600W, and the sputtering speed is 10-40 nm/min.

6. The method for preparing a nano-sized metal W film/NiTi composite board as claimed in claim 2, wherein in the step 3, the thickness of the single W film and the thickness of the single NiTi alloy film are both 5-150 nm; the total thickness of the W/NiTi nano multilayer film is 200-5000 nm.

7. The method as claimed in claim 2, wherein the initial rolling temperature is 700-900 ℃, the final rolling temperature is 900-1100 ℃, and the hot rolling deformation is 30-40% in step 4.

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