Method for quantitatively measuring inhomogeneous deformation of nano-crystal material

A uniform deformation and quantitative measurement technology, applied in the direction of applying stable tension/pressure to test the strength of materials, measuring devices, instruments, etc., can solve problems such as inability to measure, complex causes of shear bands, and uneven deformation of nanocrystalline materials

Inactive Publication Date: 2009-09-09
NANJING UNIV OF TECH
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  • Abstract
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Problems solved by technology

[0003] The purpose of the present invention is to solve the problem that the cause of shear band in nanocrystalline material is complicated and cannot be measured in

Method used

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  • Method for quantitatively measuring inhomogeneous deformation of nano-crystal material
  • Method for quantitatively measuring inhomogeneous deformation of nano-crystal material
  • Method for quantitatively measuring inhomogeneous deformation of nano-crystal material

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preparation example Construction

[0035] Preparation of samples: The tensile samples were ground and polished with diamond suspensions with a particle size of 3 μm, 1 μm, and 0.25 μm and emery paper on one side of the purchased raw materials, and the required samples were obtained by grinding and polishing to about 150 μm by electrical discharge machining . Marking is made on the tensile sample, the width and length of the marked area of ​​the tensile sample are 10 mm and 30 mm respectively and the thickness is about 150 μm.

[0036] Mechanical testing and image acquisition: Tensile samples were tested by a Zwick BZ2.5 / TS1S universal testing machine at room temperature in displacement control mode, with a quasi-static strain rate of 10 -4 the s -1 The data obtained by the material testing system can draw a relatively accurate overall stress-strain curve. The equipped digital camera (model JAI CV-A1) is used to collect images of the sample surface and connect to the computer for recording. Image, if the load ...

specific Embodiment approach

[0039] Fully dense nickel plates with a purity of 99.9% and a size of 76.2mm x 76.2mm x 0.2mm were purchased from the Canadian supplier Integran Technologies Inc, and their nominal particle size was about 20nm. The initial thickness of the nickel plate is about 0.2 mm, and the diamond suspension with a particle size of 3 μm, 1 μm, and 0.25 μm is used to grind and polish one side of it with emery paper to about 150 μm. For comparison, figure 1 The tensile specimens shown were EDM'd from ground and polished nanocrystalline nickel plates. The width and length of the marked area of ​​the tensile specimen are 10 mm and 30 mm, respectively, and the thickness is about 150 μm, which is equal to the thickness of the nickel plate.

[0040] Tensile samples were tested by a Zwick BZ2.5 / TS1S universal testing machine at room temperature in displacement control mode, with a quasi-static strain rate of 10 -4 the s -1 loaded under the condition. The testing machine has a fixed bottom grip...

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Abstract

The invention relates to a method for quantitatively measuring the inhomogeneous deformation of a nano-crystal material. The method comprises the following steps: firstly processing the measured nano-crystal material into a stretching sample, selecting a marking area on the stretching sample and marking the stretching sample; secondly, putting the stretching sample into a mechanics testing machine, and loading the stretching sample under the condition that the quasistatic strain rate of a displacement control mode at room temperature is 10<-4>s<-1>; obtaining data and displaying a stress strain curve by a material testing system of the mechanics testing machine, adopting a digital camera to acquire the image on the surface of the sample at the same time of loading, and recording the image by connecting the digital camera with a computer; and finally, carrying out digital image processing on the image acquired by the digital camera in the process of stretching to obtain the surface displacement and a stain field image of the tested image in the process of stretching. The method measures the cause of formation of a shear zone in a simple mode with low cost, so the method can have wide application prospect in the fields of modern mechanics, microelectronic technology, ultraprecise processing technology, nanometer technology, and the like.

Description

technical field [0001] The invention belongs to the field of material analysis, in particular to a method for testing the mechanical properties of nanocrystalline materials by a digital image correlation method, specifically a method for quantitatively measuring the uneven deformation of nanocrystalline materials. Background technique [0002] Nanocrystalline materials are now attracting attention because of their special mechanical properties, such as high yield strength and fracture strength, excellent wear resistance, and superplasticity in some special cases. However, since nanocrystalline materials are prone to large deformation localization and shear bands, the ductility of such materials is not high, which has become a major obstacle to the development and application of nanocrystalline materials. While limited ductility was earlier attributed to pre-existing defects such as impurities and porosity, recent good-quality specimens have shown that nanocrystalline materia...

Claims

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Application Information

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IPC IPC(8): G01N3/08G01B11/16
Inventor 周剑秋朱荣涛张舒
Owner NANJING UNIV OF TECH
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