阅读说明：本技术 一种利用冷焊接制备不同夹角晶界的设计制造装置及方法 (Design and manufacturing device and method for preparing crystal boundaries with different included angles by utilizing cold welding ) 是由 王立华 李东伟 马炎 韩晓东 邓青松 于 2021-08-04 设计创作，主要内容包括：本发明公开一种利用冷焊接制备不同夹角晶界的设计制造装置,包括支撑件,支撑件内设置有两弯曲件,两弯曲件相对设置,两弯曲件的一端均与支撑件固接,任一弯曲件远离支撑件的一端通过固定件固接有第一样品,另一弯曲件远离支撑件的一端通过固定件固接有第二样品,第一样品与第二样品对应设置；弯曲件包括热膨胀系数不同的第一金属片和第二金属片。本发明能够实现通过改变双金属片的夹角,控制第一样品和第二样品对接焊合时的角度,能够对冷焊接形成晶界的取向角进行设计；本发明装置最大限度保留聚焦离子束系统的加工视野,不影响样品对接尖端的原位原子尺度观察,同时,该装置也可以实现不同种类材料的对接焊合,制备异类材料晶界。(The invention discloses a design and manufacture device for preparing crystal boundaries with different included angles by utilizing cold welding, which comprises a supporting piece, wherein two bending pieces are arranged in the supporting piece, the two bending pieces are oppositely arranged, one ends of the two bending pieces are fixedly connected with the supporting piece, one end of any bending piece, which is far away from the supporting piece, is fixedly connected with a first sample through a fixing piece, one end of the other bending piece, which is far away from the supporting piece, is fixedly connected with a second sample through a fixing piece, and the first sample and the second sample are correspondingly arranged; the flexure includes first and second metal sheets having different coefficients of thermal expansion. The method can realize that the angle of the first sample and the second sample during butt welding can be controlled by changing the included angle of the bimetallic strip, and the orientation angle of the crystal boundary formed by cold welding can be designed; the device of the invention furthest reserves the processing visual field of a focused ion beam system, does not influence the in-situ atomic scale observation of the sample butt joint tip, and simultaneously can realize the butt welding of different materials and prepare the grain boundary of heterogeneous materials.)

1. A design and manufacture device for preparing crystal boundaries with different included angles by utilizing cold welding is characterized by comprising a support member, wherein two bending members are arranged in the support member, the two bending members are oppositely arranged, one ends of the two bending members are fixedly connected with the support member, one end of any one bending member, which is far away from the support member, is fixedly connected with a first sample (1) through a fixing member, one end of the other bending member, which is far away from the support member, is fixedly connected with a second sample (2) through a fixing member, and the first sample (1) and the second sample (2) are correspondingly arranged;

the bending part comprises a first metal sheet (3) and a second metal sheet (4) which have different thermal expansion coefficients, the first metal sheet (3) is located between the second metal sheet (4) and the supporting parts, the first metal sheet (3) is attached and fixedly connected with the second metal sheet (4), and the fixing part is fixedly connected with the second metal sheet (4).

2. The device for designing and manufacturing the grain boundaries with different included angles by using cold welding as claimed in claim 1, wherein: the support piece includes semicircle becket (5), be provided with workstation (6) in semicircle becket (5), workstation (6) with semicircle becket (5) bottom rigid coupling, first sheetmetal (3) with second sheetmetal (4) all with workstation (6) lateral wall rigid coupling, first sheetmetal (3) are located second sheetmetal (4) with between semicircle becket (5).

3. The device for designing and manufacturing the grain boundaries with different included angles by using cold welding as claimed in claim 1, wherein: the second metal sheet (4) has a thermal expansion coefficient smaller than that of the first metal sheet (3).

4. The device for designing and manufacturing the grain boundaries with different included angles by using cold welding as claimed in claim 1, wherein: the fixing piece comprises an aluminum sheet (7) fixedly connected with the second metal sheet (4), the first sample (1) is fixedly connected with the aluminum sheet (7), and the second sample (2) is fixedly connected with the aluminum sheet (7).

5. The device for designing and manufacturing the grain boundaries with different included angles by using cold welding as claimed in claim 4, wherein: the diameter that first sample (1) kept away from aluminum sheet (7) one end is less than first sample (1) is close to the diameter of aluminum sheet (7) one end, the diameter that second sample (2) kept away from aluminum sheet (7) one end is less than second sample (2) is close to the diameter of aluminum sheet (7) one end.

6. The device for designing and manufacturing the grain boundaries with different included angles by using cold welding as claimed in claim 3, wherein: the first metal sheet (3) is made of nickel, and the second metal sheet (4) is made of molybdenum.

7. The device for designing and manufacturing the grain boundaries with different included angles by using cold welding as claimed in claim 1, wherein: the distance between the two second metal sheets (4) is 30-50 mu m.

8. The use method of the design and manufacturing device for preparing the grain boundaries with different included angles by cold welding according to any one of claims 1 to 7, wherein the operation steps comprise:

a. pre-processing a first sample (1) and a second sample (2): processing the block material to form a microcolumn;

b. the first sample (1) and the second sample (2) are shaped: after step a is completed, processing the microcolumn to form a first sample (1) and a second sample (2);

c. the first sample (1) and the second sample (2) are installed: after the step b is finished, respectively fixing the first sample (1) and the second sample (2) on two second metal sheets (4);

d. starting cold welding: after step c is completed, heating the first metal sheet (3) and the second metal sheet (4);

e. the test experiment was started: after completion of step d, the heating temperature was changed and the morphological changes of the first sample (1) and the second sample (2) were observed.

9. The use method of the design and manufacture device for preparing the grain boundaries with different included angles by cold welding according to claim 8, wherein the design and manufacture device comprises: in the step a, the block material is processed by utilizing a focused ion technology to obtain the microcolumn.

10. The use method of the design and manufacture device for preparing the grain boundaries with different included angles by cold welding according to claim 8, wherein the design and manufacture device comprises: and in the step b, processing the microcolumn by using a nanometer thinning instrument to obtain a first sample (1) and a second sample (2).

Technical Field

The invention relates to the technical field of material deformation, in particular to a design and manufacturing device and method for preparing crystal boundaries with different included angles by utilizing cold welding.

Background

Due to the continuous development of the development and application of micro-nano devices, higher requirements are put forward on nano-structure materials and micro-nano processing technology, and related fields become hot spots for the research and development of materials at present. Researches find that the structure evolution and the mechanical behavior of the nano material in the deformation process are greatly different from those of a macroscopic bulk material, because the specific surface area is increased along with the reduction of the size of the material, and the function of a material interface in the deformation process is more and more prominent, the researches on the grain boundary of the nano material are crucial to the exploration of the structure evolution of the nano material and the realization of the performance design of the nano material.

Welding is an effective method for preparing a specific orientation angle grain boundary in a material, and welding of metal in a nanometer scale is also an important technical means for assembling nanometer devices from bottom to top. The existing metal welding technology generally forms a molten region between a workpiece and a solder by local heating and pressurization, and connects two or more materials into a whole by bonding and diffusion between atoms or molecules, which is called thermal welding processing, and has high requirements on processing technology. However, since the micro-nano device is very sensitive to the size and structure of the material, the material damage and internal stress caused by thermal welding may affect the performance of the micro-nano device, and thus the thermal welding technology is difficult to be applied to nano material processing. Cold welding is therefore considered a promising bottom-up nano-fabrication technique. Researchers first discovered, on a macro scale, that spontaneous cold welding of bulk metallic materials occurs due to surface atomic diffusion under conditions of high compressive stress and prolonged contact. Compared with hot welding, cold welding has the advantages of low heat input, small stress, no chemical change of materials and the like. Lu Yang et al, university of Rice, found that gold and silver nanowires with a size of 10nm or less spontaneously fuse together and form defect-free single crystal nanowires without application of heat and pressure when they are brought into contact with each other; further research has found that the cold welding phenomenon is widely present in the welding of various noble metal nanowires with characteristic dimensions of less than 10 nm. In the study of polycrystalline gold nanowire networks, Guo Chuan Fei et al, university of Houston, found that spontaneous cold welding can occur even in thicker gold nanowires (about 100nm), with substantially unchanged electrical properties. Researchers point out that the application of cold welding to the assembly of micro-nano electromechanical devices can reduce the local stress of materials, reduce the chemical reaction of a welding area and reduce or even eliminate the influence of welding on the performance of the micro-nano devices. Therefore, the research on the cold welding process of the nano material is very important for developing the next generation of advanced micro-nano electromechanical devices.

However, due to the high requirements on sample characterization and operation accuracy in the processes of nanowire extraction, positioning, docking and the like, and the sensitivity of the nanowire to environmental changes, the research on the nanowire docking welding has technical difficulties. At present, the research methods of nanowire cold welding are mainly divided into two types, and are realized in a transmission electron microscope platform: the first type is a snapping-welding method, and generally, a pre-fixed nanowire is snapped in a TEM by an MEMS device and then is butted to realize cold welding, and the method has the advantages that two snapped segments of nanowires are easy to align, the sample preparation is convenient, and the main limitation is that the cold welding of nanowires with different types and different orientations is difficult to realize; the second type is a probe method, generally a probe capable of moving in a three-dimensional direction in a TEM pole shoe is used for loading a nanowire, the other nanowire is fixed on a sample rod carrying platform, and the two nanowires are welded in a butt joint mode by controlling the movement of the probe.

Therefore, a sample preparation method and a sample preparation device which can simplify the preparation process, reduce the difficulty of nanowire extraction, positioning and butt welding, have a wide application range and simultaneously can keep the stability and the atomic scale representation precision of a sample in the process of nanowire butt welding are still the problems to be solved in the field.

Disclosure of Invention

The invention aims to provide a design and manufacturing device and a method for preparing crystal boundaries with different included angles by cold welding, which aim to solve the problems in the prior art, can realize the control of the angle of a first sample and a second sample during butt welding by changing the included angle of a bimetallic strip, and can design the orientation angle of the crystal boundaries formed by cold welding; the device of the invention furthest reserves the processing visual field of a focused ion beam system, does not influence the in-situ atomic scale observation of the sample butt joint tip, and simultaneously can realize the butt welding of different materials and prepare the grain boundary of heterogeneous materials.

In order to achieve the purpose, the invention provides the following scheme: the invention provides a design and manufacture device for preparing crystal boundaries with different included angles by utilizing cold welding, which comprises a supporting piece, wherein two bending pieces are arranged in the supporting piece, the two bending pieces are oppositely arranged, one ends of the two bending pieces are fixedly connected with the supporting piece, one end of any one bending piece, which is far away from the supporting piece, is fixedly connected with a first sample through a fixing piece, one end of the other bending piece, which is far away from the supporting piece, is fixedly connected with a second sample through a fixing piece, and the first sample and the second sample are correspondingly arranged;

the bending part comprises a first metal sheet and a second metal sheet which have different thermal expansion coefficients, the first metal sheet is located between the second metal sheet and the supporting part, the first metal sheet is fixedly connected with the second metal sheet in an attaching mode, and the fixing part is fixedly connected with the second metal sheet.

Preferably, the supporting part comprises a semicircular metal ring, a workbench is arranged in the semicircular metal ring, the workbench is fixedly connected with the bottom of the semicircular metal ring, the first metal sheet and the second metal sheet are fixedly connected with the side wall of the workbench, and the first metal sheet is located between the second metal sheet and the semicircular metal ring.

Preferably, the second metal sheet has a thermal expansion coefficient smaller than that of the first metal sheet.

Preferably, the fixing part comprises an aluminum sheet fixedly connected with the second metal sheet, the first sample is fixedly connected with the aluminum sheet, and the second sample is fixedly connected with the aluminum sheet.

Preferably, the diameter of the end, far away from the aluminum sheet, of the first sample is smaller than the diameter of the end, near the aluminum sheet, of the first sample, and the diameter of the end, far away from the aluminum sheet, of the second sample is smaller than the diameter of the end, near the aluminum sheet, of the second sample.

Preferably, the first metal sheet is made of nickel, and the second metal sheet is made of molybdenum.

Preferably, the distance between the two second metal sheets is 30 to 50 μm.

A use method of a design and manufacture device for preparing grain boundaries with different included angles by utilizing cold welding comprises the following operation steps:

a. preprocessing a first sample and a second sample: processing the block material to form a microcolumn;

b. molding the first sample and the second sample: after the step a is completed, processing the microcolumn to form a first sample and a second sample;

c. first and second sample installation: after the step b is finished, respectively fixing the first sample and the second sample on two second metal sheets;

d. starting cold welding: after step c is completed, heating the first metal sheet and the second metal sheet;

e. the test experiment was started: after step d was completed, the heating temperature was changed and the morphological changes of the first and second samples were observed.

Preferably, in the step a, the microcolumn is obtained by processing the bulk material using a focused ion technique.

Preferably, in the step b, the first sample and the second sample are obtained by processing the microcolumn with a nanometer thinning instrument.

The invention discloses the following technical effects:

1. according to the invention, the first sample and the second sample are butt-welded by utilizing the characteristic that the first metal sheet and the second metal sheet with different thermal expansion coefficients are heated and bent, and the deformation functions of the first metal sheet and the second metal sheet are comprehensively utilized, so that the first sample and the second sample are cold-welded, the material damage to the first sample and the second sample is reduced, and the material performance is improved.

2. The invention can furthest reserve the processing visual field of a focused ion beam system and control the angle of the sample during butt welding by changing the included angle between the first metal sheet and the second metal sheet.

3. The invention can realize the butt deformation of materials with the same type and different orientations, can realize the butt deformation of materials with different types and different orientations, and has the advantages of wide application range, small limitation and high practicability.

4. According to the invention, a plurality of first samples and second samples can be arranged on the bending piece at the same time, so that the simultaneous welding of a plurality of first samples and second samples is realized.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without inventive exercise.

FIG. 1 is a schematic diagram showing the positional relationship between a first sample and a second sample;

FIG. 2 is a schematic view of a first sample and a second sample being butt welded together by heating;

wherein, 1-the first sample, 2-the second sample, 3-the first metal sheet, 4-the second metal sheet, 5-the semicircle metal ring, 6-the bench, 7-the aluminum sheet.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.

The invention provides a design and manufacture device for preparing crystal boundaries with different included angles by utilizing cold welding, which comprises a supporting piece, wherein two bending pieces are arranged in the supporting piece, the two bending pieces are oppositely arranged, one ends of the two bending pieces are fixedly connected with the supporting piece, one end of any bending piece, which is far away from the supporting piece, is fixedly connected with a first sample 1 through a fixing piece, one end of the other bending piece, which is far away from the supporting piece, is fixedly connected with a second sample 2 through a fixing piece, and the first sample 1 and the second sample 2 are correspondingly arranged; the bending part comprises a first metal sheet 3 and a second metal sheet 4 which have different thermal expansion coefficients, the first metal sheet 3 is positioned between the second metal sheet 4 and the supporting part, the first metal sheet 3 is fixedly connected with the second metal sheet 4 in an attaching mode, and the fixing part is fixedly connected with the second metal sheet 4.

The first sample 1 and the second sample 2 are both nanowires, the materials of the first sample 1 and the second sample 2 can be the same or different, and the materials of the first sample 1 and the second sample 2 are selected according to actual needs, so that the application range of the device and the method is widened.

The two second metal sheets 4 are symmetrically distributed at 45 degrees, the bending part is formed by bonding the first metal sheet 3 and the second metal sheet 4 with different thermal expansion coefficients through welding, when the bending part is heated, the bending part formed by the first metal sheet 3 and the second metal sheet 4 is bent due to the different thermal expansion coefficients of the first metal sheet 3 and the second metal sheet 4, so that the first sample 1 and the second sample 2 are close, and the contact welding of the first sample 1 and the second sample 2 is cold welding because the temperature for heating the first metal sheet 3 and the second metal sheet 4 is lower than the melting point temperature of the first sample 1 or the second sample 2, compared with the existing hot welding, the material damage of the first sample 1 and the second sample 2 is reduced through the cold welding, compared with the existing cold welding, the positioning and the butt joint accuracy of the first sample 1 and the second sample 2 is improved, while allowing the cold welding process of the first sample 1 and the second sample 2 to be easily observed.

The first sample 1 and the second sample 2 are respectively arranged in parallel along the extending direction of the two second metal sheets 4 to facilitate later welding.

Set up a plurality of first samples 1 and second sample 2 on the bending member, a plurality of first samples 1 parallel arrangement, a plurality of second sample 2 parallel arrangement, because the crookedness of bending member is the same, consequently when the bending member is heated crooked, make a plurality of first samples 1 and a plurality of second sample 2 contact and weld to improve welding preparation efficiency.

Further optimize the scheme, support piece includes semicircle becket 5, is provided with workstation 6 in the semicircle becket 5, workstation 6 and 5 bottom rigid couplings of semicircle becket, and first sheetmetal 3 and second sheetmetal 4 all with 6 lateral walls rigid couplings of workstation, first sheetmetal 3 is located between second sheetmetal 4 and the semicircle becket 5. Wherein, the semicircular metal ring 5 is made of tungsten, the outer diameter is 3mm, the inner diameter is 2mm, the thickness is 15 μm-30 μm, a workbench 6 is fixedly connected in the semicircular metal ring 5, and one end of the first metal sheet 3 and one end of the second metal sheet 4 are fixedly connected on the workbench 6.

In a further optimized scheme, the thermal expansion coefficient of the second metal sheet 4 is smaller than that of the first metal sheet 3. The thermal expansion coefficient of the second metal sheet 4 relatively positioned on the inner side is relatively small, the thermal expansion coefficient of the first metal sheet 3 relatively positioned on the outer side is relatively large, the bimetallic strip is bent and deformed inwards through heating, the first sample 1 and the second sample 2 are further close to each other, and the first metal sheet 3 and the second metal sheet 4 can generate displacement with different distances through changing the heating temperature, so that the first sample 1 and the second sample 2 are subjected to cold welding at different angles.

According to a further optimized scheme, the fixing piece comprises an aluminum sheet 7 fixedly connected with the second metal sheet 4, the first sample 1 is fixedly connected with the aluminum sheet 7, and the second sample 2 is fixedly connected with the aluminum sheet 7. The aluminum sheet 7 has a length of 100 μm, a thickness of 1 μm and a width of 150 μm, and the aluminum sheet 7 functions to fix the first sample 1 or the second sample 2 to the second metal sheet 4, and to fix the first sample 1 or the second sample 2 to the aluminum sheet 7 by using a Pt-carbon gas deposition method in which the first sample 1 or the second sample 2 is placed on the aluminum sheet 7 and a Pt-carbon mixture is deposited on the aluminum sheet 7, so that the first sample 1 or the second sample 2 is fixed to the aluminum sheet 7, and can play a role in absorbing shock and preventing contamination of the first sample 1 or the second sample 2.

In a further optimized scheme, the diameter of the end, far away from the aluminum sheet 7, of the first sample 1 is smaller than that of the end, near the aluminum sheet 7, of the first sample 1, and the diameter of the end, far away from the aluminum sheet 7, of the second sample 2 is smaller than that of the end, near the aluminum sheet 7, of the second sample 2. The experimental material is accurately thinned by the microcolumn processing method, the material is processed into a pointed cone shape, the bending of the first sample 1 or the second sample 2 caused by surface tension can be effectively avoided, the stability of the first sample 1 or the second sample 2 in the deformation process is improved, and meanwhile, the in-situ atomic scale observation of the butt joint tip of the first sample 1 and the second sample 2 is not influenced.

According to a further optimized scheme, the first metal sheet 3 is made of nickel, and the second metal sheet 4 is made of molybdenum. The lengths of the first metal sheet 3 and the second metal sheet 4 are both 0.3 mm-0.5 mm, the linear thermal expansion coefficient of molybdenum is 5.2, the linear thermal expansion coefficient of nickel is 13.0, the difference of the thermal expansion coefficients is large, and the thermal stability is good.

In a further optimized scheme, the distance between the two second metal sheets 4 is 30-50 μm. Since the two second metal sheets 4 are positioned at the inner side, the distance between the two second metal sheets 4 is 30 μm to 50 μm, so that the first sample 1 and the second sample 2 are effectively welded.

A use method of a design and manufacture device for preparing grain boundaries with different included angles by utilizing cold welding comprises the following operation steps:

a. first sample 1 and second sample 2 were pre-processed: processing the bulk material to form the microcolumns. Firstly, the existing bulk materials are processed by using a focused ion beam technology to form a microcolumn, and the microcolumn is required to meet secondary processing conditions so that subsequent processing can be smoothly carried out.

b. First sample 1 and second sample 2 were shaped: after completing step a, the microcolumn is processed to form a first sample 1 and a second sample 2. Combining the focused ion beam technology with a nanometer thinning instrument (Nano Mill), processing a nanowire sample which can be observed at an atomic scale from the tip of the microcolumn, wherein the length of the nanowire sample is about 5 mu m, and the diameter of the nanowire sample is about 30 nm;

c. first sample 1 and second sample 2 were installed: after step b is completed, the first sample 1 and the second sample 2 are fixed to two second metal sheets 4, respectively. The first sample 1 was placed on the aluminum sheet 7, and a Pt-carbon mixture was deposited on the aluminum sheet 7 so that the first sample 1 was fixed to the aluminum sheet 7, and subsequently, the second sample 2 was fixed to the aluminum sheet 7 by the same operation method. And the fixed device was placed under a transmission electron microscope.

d. Starting cold welding: after step c is completed, the first metal sheet 3 and the second metal sheet 4 are heated. The temperature of the first metal sheet 3 and the second metal sheet 4 is increased, the metal thermal expansion coefficients of two sides of the bimetallic strip are different, the bimetallic strip is bent towards the inner side, the first sample 1 and the second sample 2 are driven to realize butt joint and welding, and the heating temperature for bending the bimetallic strip is generally far lower than the metal melting point, so that the butt joint and welding action of the metal nanowire at the moment can be considered as cold welding.

e. The test experiment was started: after completion of step d, the heating temperature was changed and the morphological changes of the first sample 1 and the second sample 2 were observed. In the cold welding process, the transmission electron microscope is used for carrying out in-situ observation on the atomic scale of the grain boundary formed by cold welding, and the deformation behavior of the grain boundary of the sample under the tension/compression condition can be observed by changing the temperature and the influence of the grain boundary on the material performance can be tested.

In the step a, the block material is processed by utilizing a focused ion technology to obtain the microcolumn. The focused ion technology belongs to the technology that may process materials to form micro-columns in the prior art, and is not described herein in any greater detail.

And (c) further optimizing the scheme, namely in the step (b), processing the microcolumn by using a nanometer thinning instrument to obtain a first sample 1 and a second sample 2. After the micro-column processing method is used for accurately cutting and thinning the Nano material, a Nano thinning instrument (Nano Mill) is matched to remove a gallium ion damage layer in the processing process, and the Nano material is further thinned, so that a first sample 1 and a second sample 2 of finished products are finally formed.

In the description of the present invention, it is to be understood that the terms "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on those shown in the drawings, are merely for convenience of description of the present invention, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention.

The above-described embodiments are merely illustrative of the preferred embodiments of the present invention, and do not limit the scope of the present invention, and various modifications and improvements of the technical solutions of the present invention can be made by those skilled in the art without departing from the spirit of the present invention, and the technical solutions of the present invention are within the scope of the present invention defined by the claims.