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Title: Biaxial deformation in high purity aluminum

The convergence of multiple characterization tools has been applied to investigate the relationship of microstructure on damage evolution in high purity aluminum. The extremely coarse grain size of the disc-shaped sample provided a quasi-two dimensional structure from which the location of surface-measured features could be inferred. In particular, the role of pre-existing defects on damage growth was accessible due to the presence of casting porosity in the aluminum. Micro tomography, electron backscatter diffraction, and digital image correlation were applied to interrogate the sample in three dimensions. Recently micro-bulge testing apparatus was used to deform the pre-characterized disc of aluminum in biaxial tension, and related analysis techniques were applied to map local strain fields. Subsequent post-mortem characterization of the failed sample was performed to correlate structure to damaged regions. We determined that strain localization and associated damage was most strongly correlated with grain boundary intersections and plastic anisotropy gradients between grains. Pre-existing voids played less of an apparent role than was perhaps initially expected. Finally, these combined techniques provide insight to the mechanism of damage initiation, propagation, and failure, along with a test bed for predictive damage models incorporating anisotropic microstructural effects.
Authors:
 [1] ;  [2] ;  [1] ;  [1] ;  [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  2. Office of the Under Secretary of Defense for Acquisition, Technology and Logistics, Washington, DC (United States)
Publication Date:
OSTI Identifier:
1304709
Report Number(s):
LA-UR--15-25320
Journal ID: ISSN 0921-5093
Grant/Contract Number:
AC52-06NA25396
Type:
Accepted Manuscript
Journal Name:
Materials Science and Engineering. A, Structural Materials: Properties, Microstructure and Processing
Additional Journal Information:
Journal Volume: 648; Journal Issue: C; Journal ID: ISSN 0921-5093
Publisher:
Elsevier
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE aluminum; digital image correlation; bulge test