Coming Full Circle: The Application of Microtechnology Techniques to Evaluate Bulk Materials
David T. Read, Nicholas Barbosa
A tensile test procedure that accommodates specimens with gauge section 25 μm by 70 μm by 300 μm was developed and demonstrated. The instrumentation and technique were adapted from those previously developed and used to test thin films. This required increasing both the force capacity of its load cell and the stiffness of its pull rod by replacing critical components. Specimens of the 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 grips in the form of recesses in its top surface that accepted and retained the tapered portions of the specimen grip sections. One grip was in the fixed outer portion of the frame; the other was in a plate suspended in the center of the frame by long slender beams. Force was imposed on this plate by pin loading. The force was measured using a custom load cell; the engineering strain was measured by sub-pixel digital image correlation to obtain displacements of the two ends of the gage section, using 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 Youngs modulus values were variable but within the range of expected behavior for the specimen material.
Materials Research Society Proceedings 2010 -- Symposium T -- Nanostructured Materials in Harsh Environments
November 29-December 3, 2010
Materials Research Society Fall Meeting 2010 -- Symposium T -- Nanostructured Materials in Harsh Environments