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Measuring method of mechanical properties of materials at different depths

A measurement method and depth technology, applied in the direction of testing the hardness of materials, measuring devices, analyzing materials, etc., can solve the problems of large uncertainty of measurement results, and achieve the effect of simple operation

Active Publication Date: 2020-11-10
CHINA INSTITUTE OF ATOMIC ENERGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] However, the traditional nano-indentation technology is to directly indent test the surface of the sample. The analysis of the mechanical properties of the material at different depths is achieved through different indentation depth experiments. The changing model deduces the mechanical properties at each depth, so this method is heavily dependent on the hardness-depth model and parameters used, and the uncertainty of the measurement results is large, which can reach more than 20% for inhomogeneous materials

Method used

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  • Measuring method of mechanical properties of materials at different depths
  • Measuring method of mechanical properties of materials at different depths
  • Measuring method of mechanical properties of materials at different depths

Examples

Experimental program
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Embodiment 1

[0028] (1) the initial sample with a thickness of millimeter order is prepared into a sample to be tested with an oblique section by external force; wherein the inclination of the oblique section is determined according to the gradient of the surface mechanical properties of the initial sample and the thickness of the surface thin area;

[0029] (2) Fix the sample to be tested on an object that can keep the surface of the oblique section horizontal, and use a scanning electron microscope in-situ nano-indentation instrument to perform an indentation test on the sample to be tested on the object. The indenter is vertically pressed into different positions of the oblique section; the indentation depth in the hardness test is 100-400nm; and the indentation test is carried out at a certain distance, and the distance is set to avoid the interaction between the indented plastic zones. The overlapping shall prevail; the depth of the material corresponding to the press-in position is co...

Embodiment 2

[0032] In this embodiment, the initial sample is 304L austenitic stainless steel irradiated by heavy ions, the irradiated ions are Ni at 100 MeV, the peak dose is about 150 dpa, and it is about 10 μm away from the surface. Due to high-dose ion irradiation, a large amount of carbon deposition pollution appeared on the surface of the sample, which greatly affected the results of the conventional positive nanoindentation test, and seriously affected the interpretation of the true mechanical properties of the bulk material. In addition, the damage caused by monoenergetic ion irradiation is also related to the depth, so the degree of radiation hardening at different depths is different. Ion irradiation of implanted particles also causes differences in hardness at different depths. The mechanical data obtained when indented perpendicular to the sample surface are the contribution of different depth regions in the entire plastic zone, so the obtained mechanical data cannot be clearly...

Embodiment 3

[0042] The difference from Example 2 is that sandpaper is used for the grinding, and sandpaper of 600#, 800#, 1000#, 1500#, 2000#, and 3000# are used for grinding respectively.

[0043] The polishing adopts a three-step method: the first step is to use 3 μm and 1 μm diamond polishing liquid for polishing; the second step is to use Al with a particle size of 0.05 μm 2 o 3 Polishing liquid polishing; the third step is final polishing with nano silicon dioxide to eliminate the hardened layer left by the previous two polishings.

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Abstract

The invention belongs to the technical field of testing the strength characteristics of a solid material by mechanical stress, and discloses a method for testing the mechanical properties of a material at different depths by nanoindentation. The method comprises steps of (1) preparing an initial sample by external force into a to-be-tested sample with an oblique section; and (2) fixing the to-be-tested sample to an object capable of keeping the surface of the oblique section horizontal, and using a scanning electron microscope in-situ nanoindenter to perform a press-in test on the to-be-testedsample on the object. The method achieves a measurement error of below 5% for the mechanical properties of homogeneous materials, achieves a measurement error of about 10% for the mechanical properties of non-homogeneous materials. The method is easy to operate and does not require the creation of a complex model.

Description

technical field [0001] The invention belongs to the technical field of mechanical stress testing the strength characteristics of solid materials, in particular to the application of nano-indentation technology to test the mechanical properties of materials at different depths. Background technique [0002] Nanoindentation technology is a relatively common method for testing the mechanical properties of materials at the microscale. However, it is very difficult to analyze the mechanical properties of materials after ion irradiation directly using nanoindentation instruments and commercial fixtures. This is mainly because the material will produce a damaged area on its surface after ion irradiation, and the depth of the damaged area is usually only a few microns. The damage caused by monoenergetic ions and the degree of hardening of the material after irradiation are also related to the depth. In addition, the mechanical properties of many heterogeneous materials, such as mul...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01N3/42G01N3/04G01N1/32
Inventor 马海亮袁大庆范平张乔丽朱升云
Owner CHINA INSTITUTE OF ATOMIC ENERGY