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MAEAM investigation of the structural stability and theoretical strength of Fe crystals under uniaxial loading
Author(s) -
Zhang JianMin,
Wang JingZhou,
Xu KeWei
Publication year - 2008
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/crat.200811150
Subject(s) - tetragonal crystal system , orthorhombic crystal system , compressive strength , materials science , ultimate tensile strength , phase (matter) , stress (linguistics) , uniaxial tension , condensed matter physics , crystallography , crystal structure , thermodynamics , composite material , chemistry , physics , linguistics , philosophy , organic chemistry
The structural stability and theoretical strength of BCC crystal Fe under uniaxial loading have been investigated with the modified analytic embedded‐atom method (MAEAM). Even if an orthorhombic path is applied, the deformation is spontaneous along the tetragonal path till Milstein modified Born criterion B 22 ‐B 23 >0 is violated at λ 1 =0.9064 in the compressive region. The branched orthogonal path with lower compressive stress σ 1 and energy E is preferred over the conventional tetragonal Bain path. A stress‐free FCC phase with the local maximum energy of ‐4.2186eV appearing either in compressive region (orthorhombic path) at λ 1 =0.8923 or in tensile region (tetragonal path) at λ 1 =1.2619 is unstable and would slip spontaneously into its near neighbor stress‐free mBCT phase with the local minimum energy of ‐4.2270eV. The initial BCC phase with the lowest energy of ‐4.280eV is the most stable in correspondence with the actual behavior of Fe. Furthermore, the stable region ranges from ‐79.7eV/nm 3 to 30.6eV/nm 3 in the theoretical strength or from 0.9064 to 1.1788 in the stretch λ 1 correspondingly. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)