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Coming Full Circle: The Application of Microtechnology Techniques to Evaluate Bulk Materials*

Published online by Cambridge University Press:  11 March 2011

David Read
Affiliation:
Materials Reliability Division, National Institute of Standards and Technology, Boulder, CO 80305, U.S.A.
Nicholas Barbosa
Affiliation:
Materials Reliability Division, National Institute of Standards and Technology, Boulder, CO 80305, U.S.A.
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Abstract

A tensile test procedure that accommodates specimens with gage section 25 μm thick, 70 μm wide and 360 μm long was developed and demonstrated. The instrumentation and technique were adapted from those previously developed and used to test thin films, by increasing both the force capacity of the load cell and the stiffness of the pull rod. Specimens with bow-tie geometry were fabricated by photolithography from nominally 25 μm thick full hard stainless steel 302 foil. A silicon test frame fabricated by bulk micromachining techniques included tapered grips in the form of recesses in its top surface that accepted and retained the specimen grip sections. One grip was on the fixed outer portion of the frame. The other grip was on a plate suspended in the center of the frame by long slender silicon beams. Force was imposed on this plate by pin loading. The force was measured by use of a custom load cell. The displacement was measured by sub-pixel digital image correlation to surface features on the two ends of the gage section, applied to images with a resolution of approximately 0.8 μm per pixel. Yield and ultimate strengths and elongation values consistent with vendor-provided information were obtained. The values of Young’s modulus were scattered but within the range of expected behavior for the specimen material.

Type
Articles
Copyright
Copyright © Materials Research Society 2011

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Footnotes

*

Contribution of the National Institute of Standards and Technology, an agency of the U. S. Department of Commerce. Not subject to copyright in the U.S.A.

References

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