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Title: Small scale mechanical characterization of thin foil materials via pin load microtesting

In situ scanning electron microscope (SEM) experiments, where small-scale mechanical tests are conducted on micro- and nanosized specimens, allow direct visualization of elastic and plastic responses over the entirety of the volume being deformed. This enables precise spatial and temporal correlation of slip events contributing to the plastic flow evidenced in a stress–strain curve. A new pin-loading methodology has been employed, in situ within the SEM, to conduct microtensile tests on thin polycrystalline metal foils. This approach can be tailored to a specific foil whose particular grain size may range from microns to tens of microns. Manufacture of the specialized pin grip was accomplished via silicon photolithography-based processing followed by subsequent focused ion beam finishing. Microtensile specimen preparation was achieved by combining a stencil mask methodology employing broad ion beam sputtering along with focused ion beam milling in the study of several metallic foil materials. Finite-element analyses were performed to characterize the stress and strain distributions in the pin grip and micro-specimen under load. Furthermore, under appropriately conceived test conditions, uniaxial stress–strain responses measured within these foils by pin-load microtensile testing exhibit properties consistent with larger scale tests.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [3]
  1. MicroTesting Solutions LLC, Columbus, OH (United States)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Rolls Royce LG Fuel Cell Systems Inc., North Canton, OH (United States)
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  4. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Univ. of Vermont, Burlington, VT (United States)
Publication Date:
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Experimental Mechanics
Additional Journal Information:
Journal Volume: 55; Journal Issue: 7; Journal ID: ISSN 0014-4851
Publisher:
Springer
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). High Temperature Materials Lab. (HTML)
Sponsoring Org:
Work for Others (WFO); USDOE Office of Fossil Energy (FE)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; pin loading; microtest; In situ characterization; micromechanical testing; SEM
OSTI Identifier:
1331076