A device and method for in-situ deformation of micro-nano samples in an electron microscope

Abstract

The application discloses a device and method for bending and deforming micro-nano samples in-situ in an electron microscope, and belongs to the field of scanning / transmission electron microscope accessories and micro-nano material mechanical property measurement research. The device comprises four parts, namely a supporting part, a driving part, a bending loading part and a sample stage part. One end of the nano material is fixed to a suspended part at the front end of the sample stage, and the other end is a free end. The free end of the nano material is pushed by the bending loading part driven by the heating and bending bimetallic strip, so that the nano material achieves the bending and deformation effect. The application separates and fixes the bimetallic strip and the sample, solves the problems of poor mechanical stability and easy movement of the sample in the deformation process of the in-situ bending nano material, improves the stability of the fixed sample and in-situ imaging, realizes the bending and deformation of the sample, and simultaneously observes the structural evolution of the material in the deformation process. While realizing the bending and deformation of single / multiple nano wire shafts, the structural evolution of the material in the deformation process is observed in-situ.

Description

Technical Field

[0001] This invention relates to an apparatus and method for assessing the mechanical properties of micro / nano samples during in-situ deformation under a microscope. This invention belongs to the field of research on in-situ mechanical deformation of micro / electron microscope accessories and nanomaterials. Background Technology

[0002] With the development of micro / nano fabrication and devices, nanostructured materials, as key materials for nano-assembly technology and device miniaturization, have become a hot topic in materials research and development. Since materials are often affected by external forces in practical applications, realizing the atomic-scale structural evolution of nanostructured materials under external forces is a crucial factor in evaluating their reliability. Therefore, in-situ atomic-scale characterization of the structural evolution of nanomaterials under external forces using transmission electron microscopy (TEM) plays a vital role in studying the deformation mechanism of nanomaterials under external forces, which is essential for the practical application of micro / nano materials and the development of high-performance devices. Because the distance between the sample rod and pole piece in a TEM is very small, typically only a few millimeters, the size of the mechanical system housed within the sample cavity is extremely small. Typically, sample preparation involves complex processes such as mechanical grinding, double-jet thinning, manual cutting, FIB processing, and transfer fixation, resulting in a low success rate. Furthermore, due to technological limitations, nanomaterial samples are prone to instability and vibration during bending under stress, making it difficult to achieve stable atomic-scale observation during in-situ deformation.

[0003] Therefore, developing a preparation method and apparatus that is widely applicable, has a simple preparation process, and can effectively reduce sample vibration while bending nanomaterials remains an urgent problem to be solved in this field. Summary of the Invention

[0004] To address the problems existing in current technologies, this invention provides a device and method for in-situ deformation of micro / nano-scale samples in an electron microscope. By fully utilizing the precision processing capabilities of a focused ion beam (FIB) system and a nanomill, this invention can be used to prepare devices for deforming micro / nano-scale materials in various microscopes (including scanning electron microscopes and transmission electron microscopes). This method allows for material deformation in a transmission electron microscope without sacrificing the microscope's large-angle biaxial tilting capability. Separating and fixing the bimetallic strip from the sample reduces vibration during sample transfer, loading, and stress application, significantly improving the success rate of sample preparation and the stability of in-situ imaging. This device can be applied to characterize the micro-deformation structure and mechanical properties of nanowires at the atomic scale in a transmission electron microscope.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] An apparatus and method for in-situ deformation of micro / nano samples in an electron microscope, characterized by comprising four parts: a support part, a driving part, a bending loading part, and a sample stage part; the support part is a metal ring with two symmetrical support stages on its inner ring side; the driving part is a bimetallic sheet, one end of which is vertically fixed to one side of the support platform of the inner ring of the support part, and the other end is a free end; the bending loading part is a trapezoidal metal sheet, with its wider side fixed parallel to the free end of the bimetallic sheet; the sample stage part is a trapezoidal metal sheet, with its wider end fixed to the other support platform of the support part, and its narrower end is a free end, with the nano sample vertically fixed to the free end on the side of the bending direction of the driving part, and not in contact with the bending loading part.

[0007] The support portion is a metal ring with an outer diameter of 3mm and an inner diameter of 2mm, made of copper or molybdenum, with a thickness between 30μm and 60μm. The driving portion is a bimetallic sheet, which is made of two metals with different coefficients of thermal expansion through a cold welding method. The bimetallic sheet is made of copper and nickel, with a length of 1.7mm-2.0mm. The copper side has a larger coefficient of thermal expansion, while the nickel side has a smaller coefficient of thermal expansion. Heating causes the bimetallic sheet to bend towards the nickel side. The bending loading portion is a trapezoidal high-strength metal sheet made of titanium or tungsten, with a polished surface. It is processed into a trapezoidal shape using a focused ion beam, with a length of 200μm and a thickness of 100μm. The widths of the free end and the fixed end are 50μm and 100μm, respectively. The sample stage is a trapezoidal metal sheet made of titanium or tungsten, with a length of 150μm, a free end width of 100μm, and a thickness of 200μm. The sample stage is located on the nickel side of the bimetallic sheet, with a horizontal spacing of 10-20μm.

[0008] The method for bending micro / nano materials using the above-mentioned device includes the following steps:

[0009] (1) The bending loading part and the sample stage part were fabricated from the bulk material using focused ion beam technology. They were then fixed in their respective positions by Pt-carbon gas deposition.

[0010] (2) Nanowires for deformation are fabricated from bulk materials using focused ion beam technology.

[0011] (3) Small nanowires are transferred to the free end of the sample stage in the device for in-situ deformation of micro-nano samples in an electron microscope by a tungsten needle in a focused ion beam device, so that the free end of the nanowire exceeds the tip of the bent loading part and maintains a horizontal spacing of 10-20 μm, and is fixed by Pt-carbon gas deposition.

[0012] (4) The nanowires were further thinned and the surface amorphous layer was removed using a nano mill;

[0013] (5) The device for in-situ deformation of micro-nano samples in an electron microscope with small-sized nanowires is installed into the heating sample rod and fixed. By controlling the heating stage, the bimetallic sheet is heated and bent towards the sample stage, so that the free end of the nanowire contacts the bending loading part and is bent by force. The bending deformation of small-sized micro-nano materials can be controlled by controlling the heating temperature and rate.

[0014] The present invention has the following advantages:

[0015] 1. This invention fully utilizes the precision processing capabilities of a focused ion beam system and a nanomill. The device and sample preparation steps are few, some materials are universal, making it convenient and quick, saving time and money.

[0016] 2. This invention, by fixing the driving end separately from the sample, makes it easy to fix the mounted nanomaterial sample and does not have high requirements for sample size. At the same time, it can reduce sample vibration during sample transfer, loading, and stress application, greatly improving the success rate of sample preparation and the stability of in-situ imaging;

[0017] 3. This method can achieve material deformation in a transmission electron microscope without losing the large-angle biaxial tilting function of the transmission electron microscope, enabling observation of the deformation process of nanomaterials at the atomic scale.

[0018] 4. This invention utilizes a heated sample rod, which allows for manual temperature control to adjust the bending degree of the hot bimetallic strip and control the deformation rate. Attached Figure Description

[0019] Figure 1 A schematic diagram of the device described in this invention.

[0020] Figure 2 Schematic diagram of bimetallic strip bending. Detailed Implementation

[0021] The present invention will now be described in detail with reference to the accompanying drawings, but the present invention is not limited to the following embodiments.

[0022] A device for in-situ deformation of micro / nano samples under an electron microscope comprises four parts: a support part 1, a driving part 2, a bending loading part 3, and a sample stage part 4. The support part 1 is a metal ring with an outer diameter of 3 mm and an inner diameter of 2 mm, made of copper or molybdenum, with a thickness between 30 μm and 60 μm. There are two symmetrical support stages on the inner ring side. The driving part 2 is a bimetallic sheet, one end of which is vertically fixed to one of the support platforms on the inner ring of the support part 1, and the other end is a free end. The bimetallic sheet is made of two metals with different coefficients of thermal expansion by cold welding and pressing, and the materials are copper and nickel, respectively. The length is 1.7 mm to 2.0 mm. The copper side of the bimetallic sheet has a higher coefficient of thermal expansion than the nickel side, causing the bimetallic sheet to bend towards the nickel side upon heating. The bending loading section 3 is a trapezoidal metal sheet, with its wider side fixed parallel to the free end of the bimetallic sheet. It is made of titanium or tungsten, with a polished surface, and is processed into a trapezoidal shape using a focused ion beam. It has a length of 200 μm and a thickness of 100 μm, with the free end and fixed end having widths of 50 μm and 100 μm, respectively. The sample stage section 4 is a trapezoidal metal sheet, with its wide end fixed to the support platform on the other side of the support section 1, on the nickel side of the bimetallic sheet, with a horizontal spacing of 10-20 μm. The narrow end is the free end, made of titanium or tungsten, with a length of 150 μm, a free end width of 100 μm, and a thickness of 200 μm. The nanosample 5 is vertically fixed to the free end of the sample stage section 4, initially not in contact with the bending loading section 3, with a horizontal spacing of 10-20 μm.

[0023] The method for bending micro / nano materials using the above-described device is characterized by comprising the following steps:

[0024] (1) The bending loading part and the sample stage part were fabricated from the bulk material using focused ion beam technology. They were then fixed in their respective positions by Pt-carbon gas deposition.

[0025] (2) Nanowires for deformation are fabricated from bulk materials using focused ion beam technology.

[0026] (3) Transfer small nanowires to the free end of the sample stage 4 in the device for in-situ deformation of micro-nano samples in an electron microscope by using a tungsten needle in a focused ion beam device, so that the free end of the nanowires exceeds the tip of the bent loading part and maintains a horizontal spacing of 10-20 μm, and fix it with Pt-carbon gas deposition.

[0027] (4) The nanowires were further thinned and the surface amorphous layer was removed using a nano mill;

[0028] (5) The device for in-situ deformation of micro-nano samples in an electron microscope with small-sized nanowires is installed into the heating sample rod and fixed. By controlling the heating stage, the bimetallic sheet is heated and bent towards the sample stage, so that the free end of the nanowire contacts the bending loading part and is bent by force. The bending deformation of small-sized micro-nano materials can be controlled by controlling the heating temperature and rate.

Claims

1. A device for in-situ deformation of micro / nano samples under an electron microscope, characterized in that: It includes four parts: a support part (1), a driving part (2), a bending loading part (3), and a sample stage part (4). The support part (1) is a metal ring with two symmetrical support stages on its inner ring side. The driving part (2) is a bimetallic sheet with one end vertically fixed to one side of the support platform of the inner ring of the support part (1), and the other end is a free end. The bending loading part (3) is a trapezoidal metal sheet with the wider side fixed parallel to the free end of the bimetallic sheet. The sample stage part (4) is a trapezoidal metal sheet with the wider end fixed to the other side of the support platform of the support part (1), and the narrow end is a free end. The nano sample (5) is vertically fixed to the free end on the side of the bending direction of the driving part (2) and does not contact the bending loading part (3).

2. The device for in-situ deformation of micro / nano samples in an electron microscope according to claim 1, characterized in that: The supporting part (1) is a metal ring with an outer diameter of 3 mm and an inner diameter of 2 mm. The material is copper or molybdenum, and the thickness is between 30 μm and 60 μm.

3. The device for in-situ deformation of micro / nano samples in an electron microscope according to claim 1, characterized in that: The driving part (2) is a bimetallic sheet, which is made of two metals with different coefficients of thermal expansion by cold welding. The materials are copper and nickel, and the length is 1.7mm-2.0mm. The metal on one side has a larger coefficient of thermal expansion, and the metal on the other side has a smaller coefficient of thermal expansion. Heating causes the bimetallic sheet to bend towards the nickel side.

4. The device for in-situ deformation of micro / nano samples in an electron microscope according to claim 1, characterized in that: The bending loading part (3) is a trapezoidal high-strength metal sheet made of titanium or tungsten. The surface is polished and processed into a trapezoidal shape by focused ion beam. The length is 200μm and the thickness is 100μm. The widths of the free end and the fixed end are 50μm and 100μm, respectively.

5. The device for in-situ deformation of micro / nano samples in an electron microscope according to claim 3, characterized in that: The sample stage (4) is a trapezoidal metal sheet made of titanium or tungsten, with a length of 150 μm, a width of 100 μm at the free end, and a thickness of 200 μm. The sample stage (4) is located on the nickel side of the bimetallic sheet, with a horizontal spacing of 10-20 μm.

6. A device for in-situ deformation of micro / nano samples in an electron microscope according to any one of claims 1-5, characterized in that: The method for preparing the nanosample (5) is as follows: (1) Nanowires for deformation are fabricated from bulk materials using focused ion beam technology; (2) Small nanowires are transferred to the free end of the sample stage (4) of the device for in-situ deformation of micro-nano samples in an electron microscope by a tungsten needle in a focused ion beam device, and fixed by Pt-carbon gas deposition. (3) The nanowires were further thinned and the surface amorphous layer was removed using a nano-thinning instrument; (4) The device for in-situ deformation of micro-nano samples in an electron microscope with small nanowires is installed in the heating sample rod and fixed. By controlling the heating stage, the bimetallic sheet is heated and bent towards the sample stage, so that the free end of the nanowire contacts the bending loading part and is bent by force. The bending deformation of small micro-nano materials can be controlled by controlling the heating temperature and rate. At the same time, the deformation area is observed in situ at the atomic scale using a transmission electron microscope.

Images