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Fatigue Crack Nucleation and Growth
Wed, 2007-03-07 23:26 - Yong Yang
High magnification micrographs for the micro-beam with a coarse grain structure: (a) grain structure in the near-notch region; (b) dislocation slip band structure at the load cycles of 60,000; (c) dislocation slip band structure at the load cycles of 140,000 and (d) fatigue crack morphology at the load cycles of 180,000
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More details on these intriguing fatigue crack micrographs?
Yong,
Can you provide more details of your micrographs, say, materials, geometry of the structure, loading, etc.? These information will help facilitate the discussion.
Is this published? If yes, you may also want to post a link to the published paper.
Thanks.
-Teng
some details about sample geometry and loading
Teng,
The materials are Ni thin films. Those films were fabricated using the LIGA process. The remote max stress was about 300 MPA, close to the value of fatigue endurance limit, which is defined at the number of 10^7 at a load ratio, R, of 0.1.
The 'host' thin film, in which a micro-beam was fabricated using FIB, is of dog bone shape. The gauge length is ~ 1.3 mm, width ~ 0.2 mm and thickness ~ 0.27mm. The micro-beam is 30 micron long, 5 micron wide and 0.2 micron thick, averagely speaking.
Attached is a picture showing a dog-bone thin film with a micro-beam fabricated on its surface.
The paper, about the experiments and modeling, has been submitted to Acta Materialia and accepted. I will provide the link once it is in press.
Yong
Have trouble in attaching or pasting pictures
Teng,
I'm sorry. I have trouble in attaching the picture to my previous post. The system just kept asking me to start over and change the display properties. Dose that mean the picture size is too big? How can I fix the problem?
Thanks,
Yong