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Title: Multiscale twin hierarchy in NiMnGa shape memory alloys with Fe and Cu

X-ray microdiffraction and scanning electron microscopy studies reveal 10 M martensitic structure with a highly correlated multiscale twin hierarchy organization in NiMnGaFeCu shape memory alloys. In this paper, high compatibility is found at the twin interfaces resulting in a highly correlated twinned lattice orientation across several laminate levels. The lattice unit cell is described as monoclinic I-centered with a = 4.28 Å, b = 4.27 Å, c = 5.40 Å, γ = 78.5°. The modulation is found parallel to the b axis. Finally, thin tapered needle-like lamellae and branching are observed near the twin boundaries.
 [1] ;  [2] ;  [3] ;  [3] ;  [3] ;  [4]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  2. Univ. of Tennessee, Knoxville, TN (United States)
  3. Carnegie Inst. of Washington, Argonne, IL (United States). Geophysical Lab.
  4. Center for High Pressure Science and Technology Advanced Research (HPSTAR), Shanghai (China)
Publication Date:
OSTI Identifier:
Grant/Contract Number:
NA0001974; FG02-99ER45775; AC02-06CH11357
Accepted Manuscript
Journal Name:
Acta Materialia
Additional Journal Information:
Journal Volume: 87; Journal ID: ISSN 1359-6454
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); USDOE National Nuclear Security Administration (NNSA)
Contributing Orgs:
Carnegie Inst. of Washington, Argonne, IL (United States)
Country of Publication:
United States
36 MATERIALS SCIENCE Shape memory alloys; X-ray microdiffraction; Twin boundaries; Scanning electron microscopy; Multiscale structure