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Title: Incipient plasticity of single-crystal tantalum as a function of temperature and orientation

The nanocontact plastic behavior of single-crystalline Ta (1 0 0), Ta (1 1 0) and Ta (1 1 1) was studied as a function of temperature and indentation rate. Tantalum, a representative body centred cubic (BCC) metal, reveals a unique deformation behavior dominated by twinning and the generation of stacking faults. Experiments performed at room temperature exhibit a single pop-in event, while at 200 °C, above the critical temperature, a transition to multiple pop-ins was observed. The experimental results are discussed with respect to the orientation as well as temperature and correlated to the defect structures using both anisotropic finite element and MD simulations. In addition, the serrated flow observed at 200 °C is related to differences in the quasi-elastic reloading originating from changes in the defect mechanism.
Authors:
 [1] ;  [2] ;  [2] ;  [1] ;  [3] ;  [4] ;  [1]
  1. Univ. of Southern California, Los Angeles, CA (United States)
  2. Univ. Politecnica de Catalunya, Barcelona (Spain)
  3. Univ. of Southern California, Los Angeles, CA (United States); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  4. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Publication Date:
OSTI Identifier:
1324509
Report Number(s):
LLNL-JRNL--694601
Journal ID: ISSN 1478-6435
Grant/Contract Number:
AC52-07NA27344
Type:
Accepted Manuscript
Journal Name:
Philosophical Magazine (2003, Print)
Additional Journal Information:
Journal Name: Philosophical Magazine (2003, Print); Journal Volume: 95; Journal Issue: 16-18; Journal ID: ISSN 1478-6435
Publisher:
Taylor & Francis
Research Org:
Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY nanomechanics; tantalum; finite-element modelling; nanoindentation