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Method for testing hardness of metal material under different pressing-in depths

A technology of metal materials and indentation depth, which is applied in the direction of testing material hardness, preparation of test samples, and analysis of materials, etc., can solve the problems of long time consumption, high cost of experiments, and many times of experiments, etc., to achieve simple operation and limitations Small, reduce the effect of experiment time and cost

Active Publication Date: 2018-03-23
JILIN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method has the disadvantages of long time consumption, too many experiments, and high experiment cost, and it is impossible to obtain a continuous hardness-displacement curve.
Although continuous stiffness technology can obtain a continuous hardness-displacement curve under constant strain rate loading, it cannot be loaded at a constant load rate and cannot obtain a hardness-displacement curve during the load-holding stage, which has limitations

Method used

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  • Method for testing hardness of metal material under different pressing-in depths
  • Method for testing hardness of metal material under different pressing-in depths
  • Method for testing hardness of metal material under different pressing-in depths

Examples

Experimental program
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Effect test

Embodiment 1

[0039] A method for testing the hardness of nanocrystalline copper at different depths under constant load rate loading, the specific steps are as follows:

[0040] A. Sample processing:

[0041] After the surface of the nanocrystalline copper sample to be tested is polished with metallographic sandpaper of No. 360, No. 600, No. 1000 and No. 1500 in turn, use a polishing machine to polish it to a bright effect, and then put it into a beaker filled with absolute ethanol. in the ultrasonic cleaning machine for 10 minutes, and then rinse with deionized water for 30s to remove the residue on the surface;

[0042] B. Nanoindentation test:

[0043] Perform nanoindentation test on the nanocrystalline copper sample treated in step A, set the maximum load of 300mN, the loading time of 60s, and hold the load at the maximum load for 1000s. A total of 20 points are tested to obtain the load-displacement curve and the average elastic modulus. Quantity E = 104.39GPa and maximum depth h L...

Embodiment 2

[0047] A method for testing the hardness of magnesium at different indentation depths under constant strain rate loading, the specific steps are as follows:

[0048] A. Sample processing:

[0049]After the surface of the magnesium sample to be tested is polished with metallographic sandpaper of No. 360, No. 600, No. 1000, and No. 1500 in turn, use a polishing machine to polish it to a mirror effect, and then put it into a beaker with anhydrous ethanol, Clean in an ultrasonic cleaner for 10 minutes, then rinse with deionized water for 30s to remove residues on the surface;

[0050] B. Nanoindentation test:

[0051] Perform nanoindentation test on the magnesium sample treated in step A, set the maximum indentation depth to 2000nm and the loading strain rate to 0.4s -1 , hold the load at the maximum load for 500s, test 10 points in total, and obtain the load-displacement curve, the elastic modulus E=40.52GPa and the depth h L = Contact stiffness S at 3077.41 nm h =713429.03N / ...

Embodiment 3

[0055] A method for testing the hardness of copper at different indentation depths under constant strain rate loading, the specific steps are as follows:

[0056] A. Sample processing:

[0057] After the surface of the copper sample to be tested is polished with metallographic sandpaper of No. 360, No. 600, No. 1000 and No. 1500 in turn, use a polishing machine to polish it to a mirror effect, and then put it into a beaker with anhydrous ethanol, Clean in an ultrasonic cleaner for 5 minutes, then rinse with deionized water for 10 seconds to remove residues on the surface;

[0058] B. Nanoindentation test:

[0059] Perform nanoindentation test on the copper sample treated in step A, set the maximum indentation depth to 2000nm and the loading strain rate to 0.1s -1 , the holding time is 0s, a total of 10 points are tested, and the load-displacement curve is obtained, the elastic modulus E=114.34GPa and the depth h L = Contact stiffness S at 2003.56 nm h =1286469.11N / m;

[0...

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Abstract

The invention discloses a method for testing the hardness of a metal material under different pressing-in depths, and belongs to the technical field of hardness testing. In the method, a nanoindentation test is adopted to obtain data of the material, such as a load-displacement curve, an elastic modulus and contact rigidity, and the hardness of the metal material under different pressing-in depthsis obtained by calculation. According to the method, a continuous hardness-displacement curve can be obtained by only one nanoindentation test, so that the experimental time and cost are greatly reduced; moreover, the method is convenient to operate, is less limited, and is applicable to not only a loading stage of a nanoindentation experiment but also a load preservation stage; therefore, a basis is provided for subsequent researches, and the method has broad application prospect.

Description

technical field [0001] The invention belongs to the technical field of hardness testing, and particularly relates to a method for testing the hardness of metal materials at different indentation depths. Background technique [0002] Nanoindentation test is an advanced micro-nanomechanical testing technology, which can be divided into quasi-static method and continuous stiffness measurement method. The former obtains a continuous load-displacement curve by measuring the relationship between the load and the depth of the indentation sample surface, thereby obtaining the hardness and elastic modulus at a point at the maximum indentation depth of the material. The latter provides another dynamic measurement method to obtain hardness, elastic modulus, contact stiffness, etc. as a continuous function of indentation depth through a single loading and unloading cycle. Nanoindentation testing has the advantages of high load and displacement resolution, small sample size, and non-des...

Claims

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Application Information

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IPC IPC(8): G01N3/42G01N1/32
CPCG01N1/32G01N3/42G01N2203/0012G01N2203/0019G01N2203/0078G01N2203/0208G01N2203/0682
Inventor 孙巍铭江月江忠浩连建设孙贵训张晓茹刘绍成张腊双李欣义
Owner JILIN UNIV