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Test method for testing bending fatigue life of film

A bending fatigue and test method technology, which is applied in the direction of applying repetitive force/pulsation force to test the strength of materials, etc., can solve the problems of taking a lot of time and cost, not applicable to insulating films, not applicable to bending fatigue behavior of film materials, etc., to save Time and cost, quick and easy to obtain, widely applicable results

Inactive Publication Date: 2015-04-15
SOUTHWEST JIAOTONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] In the Chinese patent "A test method for testing the fatigue characteristics of nano-thick films" (patent document number CN101251456B), the indentation equipment is used to perform fatigue experiments on nano-films, and the fatigue life of the films is determined by analyzing the number of cycles when the contact stiffness continuously declines sharply. However, this method can only test the impact fatigue behavior of the film, and is not suitable for the study of the bending fatigue behavior of the film material.
The Chinese patent "Dynamic Bending Fatigue Performance Test System and Test Method for Thin Film Materials" (Patent Document No. CN101571467B) utilizes the electromagnetic force received by the energized coil in a constant magnetic field to drive the free end of the cantilever beam to vibrate reciprocally relative to its equilibrium position. Fatigue loads are applied to samples of various materials. However, this technology does not provide a method for quantitatively determining the magnitude of the load on the sample, so it is impossible to obtain the S-N curve describing the fatigue behavior of the thin film material.
The Chinese patent "Measurement Method for Fatigue Life of Metal Thin Films on Flexible Substrates" (Patent Document No. CN101226163A) judges whether the metal thin film fails by recording the change of resistance, but this method is not suitable for insulating thin films
[0004] In addition, in the existing test methods for the fatigue performance of thin film materials, each experiment can only test the fatigue behavior under one stress range. If the S-N curve is to be obtained, it will take a lot of time and cost

Method used

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  • Test method for testing bending fatigue life of film

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0042] Using cobalt alloy as the substrate 101, the bending fatigue life of the titania film 102 deposited on the surface of the substrate 101 under different stress amplitudes was tested. Below this sample sample 1 is taken as an example to illustrate the principle and specific operation steps of the inventive method:

[0043] A. Process the cobalt-based alloy into a flake shape with a length l of 150 mm, a width b of 7 mm, and a thickness h of 0.7 mm as the substrate 101, and then deposit five pieces of 7×7 mm on the surface of the substrate 101 by magnetron sputtering at equal intervals 2 The rutile-type titanium dioxide film 102 is used as a sample 1, the thickness w of the film 102 is 80nm, and the elastic modulus E=24000Mpa of the cobalt-based alloy;

[0044] B. Using the cantilever beam vibration equipment 2 to make the sample 1 perform cantilever beam bending vibration, the sample 1 is subjected to cantilever beam bending vibration so that the film 102 deposited on its...

Embodiment 2

[0050] The bending fatigue life of TiN and DLC subjected to the same stress amplitude on the surface of the stainless steel substrate 101 was tested. The process of this embodiment is basically the same as that of Embodiment 1, the difference is that TiN and DLC are respectively deposited on the front and back sides of the same position of the cantilever beam sample 1, and the fatigue life of two different films 102 under the same stress range can be tested at the same time , thus saving test time and cost. The experimental results show that under the stress amplitude of 140Mpa, the fatigue life of 1 micron TiN is 3.5 million times, and the fatigue life of 0.5 micron DLC is 3 million times.

Embodiment 3～15

[0052] Embodiments 3 to 15 have the same operating steps as in Example 1, except that the base material and size of the sample are different; the type of film to be detected and the thickness of the film are different; the frequency of the sample vibration is different; the time of each vibration is different; The spacing of sampling points is different when the amplitude is distributed. The specific parameters above are shown in the table below:

[0053]

[0054]

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Abstract

The invention discloses a test method for testing bending fatigue life of a film, which is wide in applicability, simple to operate and capable of quickly and conveniently obtaining the bending fatigue life of a film. The test method comprises the following steps of: continuously applying alternating load for stretching and compressing on a film deposited on the surface of a test specimen through the bending vibration of the test specimen, analyzing the amplitude change of the test specimen from a free end to a fixed end to determine the alternating stress amplitude of the film, observing whether the film on the surface of a cantilever beam cracks or drops after the cantilever beam vibrates for a special time t0 each time, measuring the fatigue life time of the film, and drawing an S-N curve. The test method is wide in adaptability and very simple to operate, and can be used for simultaneously researching the bending fatigue behaviors of a film material under different stress amplitudes within one test period, greatly saving the time and cost for drawing the S-N curve and quickly and conveniently obtaining the bending fatigue life of the film. The test method is suitable for generalization and application in the field of fatigue property tests of film materials.

Description

technical field [0001] The invention relates to the field of testing the fatigue performance of thin film materials, in particular to a test method for testing the bending fatigue life of thin films. Background technique [0002] In modern society, various thin film materials have been widely used in the fields of machinery, electronics, photochemistry, sensors, and biomedical engineering. In the application process of some fields, thin film materials will be subjected to cyclic loading and fatigue behavior will occur. For example, in order to improve the biocompatibility of metal vascular stents, an inorganic thin film TiO with anticoagulant effect can be deposited on its surface. 2 , DLC or some organic drug coatings for surface modification, but after the vascular stent is implanted in the human body, with the periodic changes in blood pressure, the vascular stent will also periodically expand and contract, thereby stretching the film on its surface, Compressive alterna...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01N3/32
Inventor 谢东冷永祥黄楠
Owner SOUTHWEST JIAOTONG UNIV
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