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Title: Intragranular twinning, detwinning, and twinning-like lattice reorientation in magnesium alloys

We present that deformation twinning plays a critical role on improving metals or alloys ductility, especially for hexagonal close-packed materials with low symmetry crystal structure. A rolled Mg alloy was selected as a model system to investigate the extension twinning behaviors and characteristics of parent-twin interactions by nondestructive in situ 3D synchrotron X-ray microbeam diffraction. Besides twinning- detwinning process, the twinning-like lattice reorientation process was captured within an individual grain inside a bulk material during the strain reversal. The distributions of parent, twin, and reorientated grains and sub-micron level strain variation across the twin boundary are revealed. A theoretical calculation of the lattice strain confirms that the internal strain distribution in parent and twinned grains correlates with the experimental setup, grain orientation of parent, twin, and surrounding grains, as well as the strain path changes. In conclusion, the study suggests a novel deformation mechanism within the hexagonal close-packed structure that cannot be determined from surface-based characterization methods.
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [6] ;  [2] ;  [1]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical and Engineering Materials Division
  2. Univ. of Tennessee, Knoxville, TN (United States). Department of Materials Science and Engineering
  3. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division
  4. AVIC Beijing Institute of Aeronautical Materials, Beijing (China)
  5. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division
  6. Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Publication Date:
OSTI Identifier:
Grant/Contract Number:
AC05-00OR22725; FE-0008855; FE-0024054; FE-0011194
Accepted Manuscript
Journal Name:
Acta Materialia
Additional Journal Information:
Journal Volume: 121; Journal ID: ISSN 1359-6454
Research Org:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences (CNMS); Spallation Neutron Source
Sponsoring Org:
USDOE Office of Science (SC); ORNL LDRD Director's R&D; USDOE Office of Fossil Energy (FE)
Country of Publication:
United States
36 MATERIALS SCIENCE Magnesium alloy; Twinning; Synchrotron X-ray; Deformation mechanism