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Method for calculating critical slitting stress of twin crystals through EBSD technology and Vickers hardness tester

A critical cutting stress, Vickers hardness tester technology, applied in the direction of testing material hardness, analyzing materials, strength characteristics, etc., can solve the problems of high cost, low popularity, and can not reflect the size of critical cutting stress, and achieve convenient The effect of measurement, accurate measurement

Active Publication Date: 2020-03-31
INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The value of the critical shear stress of twins simulated by the VPSC model cannot reflect the actual critical shear stress
Although experiments such as micro-cantilever beam compression can accurately measure the critical shear stress of twins, it requires high-end and expensive instruments to achieve, which is costly and not widely available.
Therefore, it is difficult to find an affordable and simple and convenient method to measure the actual critical shear stress of twins

Method used

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  • Method for calculating critical slitting stress of twin crystals through EBSD technology and Vickers hardness tester
  • Method for calculating critical slitting stress of twin crystals through EBSD technology and Vickers hardness tester
  • Method for calculating critical slitting stress of twin crystals through EBSD technology and Vickers hardness tester

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Embodiment 1

[0037] The method for calculating the critical shear stress of twins by EBSD technology and Vickers hardness tester comprises the following steps:

[0038] 1), EBSD sample preparation (to ensure the flatness of the sample):

[0039] First mount the sample on the sample mounting machine, and then pre-grind with 150#, 320#, 800#, 2000# water sandpaper in sequence. After removing deep scratches, perform vibration polishing on the automatic polishing machine. The polishing liquid is SiO 2 Nano-suspension solution, polished for about 1 hour, and finally a bright and trace-free polished surface with a mirror effect;

[0040] 2) Mark a certain position on the surface of the sample with Vickers hardness, and record the original morphology and crystal orientation of the area through metallographic microscope, scanning electron microscope and EBSD;

[0041] 3) Measure the hardness of the area with a Vickers hardness tester, change loads of different sizes (from 10-1000g), until twins ...

Embodiment 2

[0046] The method of calculating the critical splitting stress of twins by EBSD technology and Vickers hardness tester, the critical splitting stress of {11-21} twinning is measured by the method described above for the Zr-4 alloy in the quenched state in the β phase region .

[0047] The nominal composition of Zr-4 alloy is Zr-1.5Sn-0.2Fe-0.1Cr. This alloy has very low thermal neutron absorption cross section, high hardness, ductility and excellent corrosion resistance. It is mainly used in pressurized water reactors, Fuel cladding materials in boiling water reactors, heavy water reactors.

[0048] The first is the preparation of EBSD samples. EBSD samples are prepared after wire cutting samples, grinding and mechanical vibration polishing. Observe the shape change before and after the Vickers hardness indenter is pressed in through a metallographic microscope, such as image 3 shown. Keep under the load of 500g for 10 seconds, the hardness measured by Vickers hardness teste...

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Abstract

The invention discloses a method for calculating critical slitting stress of twin crystals through an EBSD technology and a Vickers hardness tester. According to the method, the critical slitting stress of twin crystals is finally obtained mainly by geometrically analyzing and calculating Vickers hardness indentations with different loads and combining the functions of EBSD calibration crystal orientation and twin crystals. The calculation process of the method comprises the following steps: firstly, preparing an EBSD blocky sample, and ensuring the flatness of the surface of the sample through chemical wiping corrosion or mechanical vibration polishing; measuring a certain area of the sample by using a metallographic microscope and EBSD, and marking the position by using Vickers hardness;then carrying out hardness testing on the area through Vickers hardness of different loads until twin crystals appear beside the hardness indentation under a certain load, and recording the diagonalsize and the hardness value of the hardness indentation; and then calibrating the type of the twin crystal by using EBSD, and finally obtaining the critical slitting stress of the twin crystal by combining hardness indentation geometric analysis calculation under the load with Schmid factor calculation.

Description

technical field [0001] The invention belongs to the field of material analysis, and in particular provides a method for calculating the critical splitting stress of twins through EBSD technology and a Vickers hardness tester. Background technique [0002] Vickers hardness is to use a diamond pyramid indenter with an included angle of 136° to press into the outer surface of the sample under a specified load, keep the load for a certain period of time, and then remove the load, and obtain the indentation by measuring the length of the diagonal. Geometric relationship, calculate the surface area of ​​the indentation, and then calculate the average pressure of the indentation surface area, which is the Vickers hardness value (HV) of the material. [0003] Under a certain load, the Vickers hardness indenter is pressed into the surface of the material, which means that the material is subjected to compressive stress, and the material will be deformed, and the two main ways of defo...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N23/2005G01N23/20058G01N23/203G01N23/2202G01N23/2206G01N3/40G01N1/28G01N1/32
CPCG01N23/2005G01N23/203G01N23/20058G01N23/2206G01N23/2202G01N3/40G01N1/286G01N1/32G01N2203/0078G01N2203/0298G01N2203/0682G01N2203/0676G01N2001/2873
Inventor 李阁平张英东袁福森韩福洲穆罕默德·阿里郭文斌任杰刘承泽顾恒飞
Owner INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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