Regulation and control method for {100} surface micro-nano pattern of face-centered cubic single crystal material

Abstract

The invention discloses a {100} surface micro-nano pattern regulation and control method of a face-centered cubic single crystal material, and belongs to the field of material surface patterning processing. According to the method, the type, height and range of the surface pattern are changed by regulating and controlling the stacking fault energy and deformation strain rate of the face-centered cubic single crystal material, the decomposition and plug volume of the dislocation can be improved by reducing the stacking fault of the face-centered cubic single crystal material, and the interaction and rearrangement process of the dislocation are increased; according to the method disclosed by the invention, the dominant symmetry of bulge distribution is converted into the dominant symmetry of the pressure head from the dominant symmetry of the crystal, and the height of the surface bulge is reduced by improving the loading rate of the indentation, increasing the proliferation rate of dislocation and improving the motion resistance of the dislocation. Therefore, the indentation surface pattern on the surface is changed efficiently at low cost, and an effective way can be provided for fine processing of a three-dimensional microstructure on the surface.

Description

Technical Field

[0001] The invention belongs to the field of material surface patterning processing, and in particular relates to a method for regulating a {100} surface micro-nano pattern of a face-centered cubic single crystal material. Background Art

[0002] Constructing micro-nanoscale three-dimensional structures on the surface of materials can give them unique wetting, optics, friction, biocompatibility and other excellent properties, and has broad application prospects in many fields such as semiconductor chips, energy, biomedicine and mechanical protection.

[0003] At present, the main method for preparing surface patterns is photolithography. This technology is mature and can accurately control the surface morphology, but the cumbersome steps and expensive equipment limit their wider application. Imprinting technology based on the indentation process has the advantages of simplicity, low cost, and easy operation. However, during the indentation process of metal materials, the surrounding materials will rise and sink. Therefore, the development of a simple and efficient control method is of great significance to the field of patterning. Summary of the invention

[0004] Purpose of the invention: In order to solve the problems existing in the prior art, the purpose of the present invention is to provide a simple, efficient and widely applicable method for regulating the {100} surface micro-nano pattern of face-centered cubic single crystal materials.

[0005] Technical solution: The method for controlling the {100} surface micro-nano pattern of a face-centered cubic single crystal material of the present invention comprises the following steps:

[0006] (1) Using a nanoindentation processing instrument to indent the {100} surface of a face-centered cubic single crystal material, a residual indentation and a surrounding material ridge pattern are obtained;

[0007] (2) By reducing the stacking fault energy of the face-centered cubic single crystal material, the material ridge pattern is transformed from being dominated by crystal symmetry to being dominated by indenter symmetry;

[0008] (3) Finally, by increasing the loading strain rate of the indentation process, the size of the material protrusion pattern is reduced, thereby achieving the regulation of the surface micro-nano pattern.

[0009] Furthermore, in step (1), the surface roughness Ra of the face-centered cubic single crystal material is less than 100 nm.

[0010] Furthermore, in step (1), the indentation processing instrument is a nanoindenter, which can adjust the parameters to achieve a strain rate of 10 -5 -10 4 s -1 The nanoindentation instrument uses a triangular pyramid-shaped Bosch indenter, a spherical indenter and a quadrangular pyramid-shaped Vickers indenter.

[0011] Furthermore, in step (1), the depth of the residual indentation is less than 10 μm.

[0012] Furthermore, in step (1), the loading strain rate of the nanoindentation is less than 10 s -1 .

[0013] Furthermore, in step (2), the stacking fault energy of the face-centered cubic single crystal is reduced by element doping or material replacement.

[0014] Furthermore, in step (2), the crystal symmetry is dominated by the 4-fold symmetry on the {100} plane, and the indenter symmetry is dominated by the 3-fold symmetry corresponding to the Bosch indenter.

[0015] Furthermore, in step (2), the stacking fault energy of the face-centered cubic single crystal material is reduced to ≤40 mJ m -2 .

[0016] Furthermore, in step (3), the loading strain rate is greater than 10 3 s -1 .

[0017] Principle of the invention: The present invention firstly uses nano-indentation technology to prepare micro-nano-sized indentations and surrounding ridges on the surface of face-centered cubic single crystal material {100}; secondly, by reducing the stacking fault energy of the material, increasing the decomposition and accumulation of dislocations, promoting the dislocation rearrangement process, forming a large number of sub-grains to change the crystal orientation, and transforming the symmetry of the surface ridge distribution into the same symmetry as the indenter. Finally, by increasing the loading rate of the indentation, increasing the proliferation rate of dislocations, increasing the movement resistance of dislocations, and reducing the height of the surface ridges, the above steps can be combined to achieve the regulation of surface micro-nano patterns.

[0018] Beneficial effects: Compared with the prior art, the present invention has the following significant effects: (1) The present invention is based on the underlying mechanism of plastic deformation of face-centered cubic single crystal materials. By changing the intrinsic factors (stacking fault energy) and extrinsic factors (nanoindentation loading rate) of face-centered cubic single crystal materials, the nucleation and movement of dislocations are comprehensively regulated, thereby achieving the purpose of controlling the surface plastic morphology; (2) The method for regulating the {100} surface micro-nano pattern of face-centered cubic single crystal materials based on the present invention is simple and stable, and is applicable to a variety of materials with face-centered cubic structure; (3) The present invention can realize the construction of a variety of surface patterns by regulating stacking fault energy and strain rate, and is expected to become a surface superstructure design method to improve the lubricity, hydrophobicity, biocompatibility and optical properties of the material surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The copper and nickel single crystals and their x-ray diffraction patterns in Example 1;

[0020] Figure 2 This is a curve diagram of strain rate versus loading time in low strain rate nanoindentation loading in Example 1;

[0021] Figure 3 This is a curve diagram of strain rate versus loading time in high strain rate nanoindentation loading in Example 1;

[0022] Figure 4 This is the surface morphology of the copper / nickel single crystal after nanoindentation analysis using atomic force microscopy in Example 1;

[0023] Figure 5 This is a microstructure diagram of a copper / nickel single crystal after low strain rate nanoindentation analysis using a transmission electron microscope in Example 1;

[0024] Figure 6 This is a microstructure diagram of the copper / nickel single crystal after high strain rate nanoindentation analysis using a transmission electron microscope in Example 1. DETAILED DESCRIPTION

[0025] The present invention is further described in detail below in conjunction with the embodiments and drawings.

[0026] Example 1: The method for controlling the {100} surface micro-nano pattern of a face-centered cubic single crystal material provided in this example comprises the following steps:

[0027] (1) First, two face-centered cubic single crystal materials with different stacking fault energies are selected, such as Figure 1 The copper with (100) crystal plane (stack fault energy is 40 mJ m -2 ) and nickel single crystal (stack fault energy is 128mJ m -2 ). After mechanical grinding and polishing, a smooth and clean surface is obtained with a roughness Ra<10nm.

[0028] (2) The NanoTest nano-indentation equipment produced by Micro Materials in the UK was used to carry out an indentation experiment on the surface of a nickel single crystal. The indenter used a triangular pyramid-shaped Bosch indenter. The loading parameters were: loading rate 1 mN / s, maximum load 50 mN, load was maintained for 10 s and then unloaded at the same rate, the indentation process was repeated 5 times, and the interval between each indentation was 50 m.

[0029] (3) Changing the stacking fault energy of the matrix (for the convenience of the experiment, the present invention selects copper single crystals with small stacking fault energy for the experiment, replacing the step of reducing the stacking fault energy), and using the same loading parameters for indentation processing. Figure 2 As shown, the strain rate during loading is less than 10s -1 .

[0030] (3) In order to increase the loading strain rate, the nano-impact mode of the NanoTest equipment was used to prepare indentations of similar size. The loading parameters were: acceleration load 6 mN, acceleration distance 10 m, processing repeated 5 times, and the interval between each indentation was 50 m. Figure 3 As shown, the strain rate during loading is greater than 10 3 s -1 .

[0031] Surface pattern characterization: Atomic force microscopy (Dimension ICON) was used to analyze the surface morphology after indentation, such as Figure 4 As shown. The ridge morphology around the indentation of the nickel single crystal with high stacking fault energy at a low strain rate shows four-axis symmetry, while after being converted into a copper single crystal with low stacking fault energy, the ridge morphology around the indentation becomes three-axis symmetric. This shows that the reduction of stacking fault energy can regulate the symmetry of the surface pattern. Further, the surface morphology under high strain rate nanoindentation was compared, and its symmetry did not change, but the average ratio of the ridge height to the indentation depth decreased, which shows that the increase in strain rate can reduce the height and range of the surface ridge.

[0032] The microstructure beneath the low strain rate nanoindentation ridge structure was analyzed using transmission electron microscopy, e.g. Figure 5 As shown in the figure, a large number of long and straight parallel dislocation lines appeared in the nickel single crystal, while subcrystals and curved dislocation lines appeared in the copper single crystal. This shows that the bulge morphology is caused by the slip movement of a large number of dislocations. At the same time, reducing the stacking fault energy can increase the decomposition and interaction of dislocations, leading to local orientation changes, the anisotropy of the single crystal is destroyed, and the bulge direction is affected by the stress field caused by the indenter.

[0033] The microstructure beneath the high strain rate nanoindentation ridges was analyzed using transmission electron microscopy, e.g. Figure 6 As shown in the figure, small-angle grain boundaries appear in nickel single crystals, and large-angle grain boundaries appear in copper single crystals. This shows that the increase in strain rate can accelerate the decomposition of dislocations and promote the rearrangement of dislocations into small-angle grain boundaries and large-angle grain boundaries, thereby increasing the movement resistance of subsequent dislocations and reducing the height and range of surface bulges.

[0034] In summary, in the method for regulating the {100} surface micro-nano pattern of a face-centered cubic single crystal material provided by the present invention, an indentation and surrounding protrusion morphology are constructed on the surface of the face-centered cubic single crystal material by a nanoindenter, the symmetry of the protrusion morphology is changed by reducing the stacking fault energy of the material, and the range and height of the protrusion are reduced by increasing the loading strain rate.

Claims

1. A method for regulating the {100} surface micro-nano pattern of a face-centered cubic single crystal material, characterized in that: The following steps are involved: (1) Using a nanoindentation processing instrument to indent the {100} surface of a face-centered cubic single crystal material, a residual indentation and a surrounding material ridge pattern are obtained; (2) By reducing the stacking fault energy of the face-centered cubic single crystal material, the material ridge pattern is transformed from being dominated by crystal symmetry to being dominated by indenter symmetry; (3) Finally, by increasing the loading strain rate of the indentation process, the size of the material protrusion pattern is reduced, thereby achieving the regulation of the surface micro-nano pattern.

2. The method for controlling the {100} surface micro-nano pattern of a face-centered cubic single crystal material according to claim 1, characterized in that: In step (1), the surface roughness Ra of the face-centered cubic single crystal material is less than 100 nm.

3. The method for controlling the {100} surface micro-nano pattern of a face-centered cubic single crystal material according to claim 1, characterized in that: In step (1), the indentation processing instrument is a nanoindenter, which can adjust the parameters to achieve a strain rate of 10 -5 -10 4 s -1 Varies within range.

4. The method for controlling the {100} surface micro-nano pattern of a face-centered cubic single crystal material according to claim 3, characterized in that: In step (1), the indenter used in the nanoindentation instrument is a triangular pyramid-shaped Bosch indenter.

5. The method for controlling the {100} surface micro-nano pattern of a face-centered cubic single crystal material according to claim 1, characterized in that: In step (1), the depth of the residual indentation is less than 10 μm.

6. The method for controlling the {100} surface micro-nano pattern of a face-centered cubic single crystal material according to claim 1, characterized in that: In step (1), the strain rate of nanoindentation is less than 10 s- 1 .

7. The method for controlling the {100} surface micro-nano pattern of a face-centered cubic single crystal material according to claim 1, characterized in that: In step (2), the method of reducing the stacking fault energy of the face-centered cubic single crystal is: element doping.

8. The method for controlling the {100} surface micro-nano pattern of a face-centered cubic single crystal material according to claim 1, characterized in that: In step (2), the crystal symmetry is dominated by the 4-fold symmetry on the {100} plane, and the indenter symmetry is dominated by the 3-fold symmetry corresponding to the Bosch indenter.

9. The method for controlling the {100} surface micro-nano pattern of a face-centered cubic single crystal material according to claim 1, characterized in that: In step (2), the stacking fault energy of the face-centered cubic single crystal material is reduced to ≤40 mJ m -2 .

10. The method for controlling the {100} surface micro-nano pattern of a face-centered cubic single crystal material according to claim 1, characterized in that: In step (3), the loading strain rate is greater than 10 3 s -1 .

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