Initial dislocation structure and dynamic dislocation multiplication in Mo single crystals [electronic resource].
- Washington, D.C. : United States. Dept. of Energy, 2000.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
- Physical Description:
- PDF-FILE: 9 ; SIZE: 5 MBYTES pages
- Additional Creators:
- Lawrence Livermore National Laboratory
United States. Department of Energy
United States. Department of Energy. Office of Scientific and Technical Information
- Initial dislocation structure in annealed high-purity Mo single crystals and deformation substructure in a crystal subjected to 1% compression have been examined and studied in order to investigate dislocation multiplication mechanisms in the early stages of plastic deformation. The initial dislocation density is in a range of 10⁶ ≈ 10⁷ cm⁻², and the dislocation structure is found to contain many grown-in superjogs along dislocation lines. The dislocation density increases to a range of 10⁸ ≈ 10⁹ cm⁻², and the average jog height is also found to increase after compressing for a total strain of 1%. It is proposed that the preexisting jogged screw dislocations can act as (multiple) dislocation multiplication sources when deformed under quasi-static conditions. Both the jog height and length of link segment (between jogs) can increase by stress-induced jog coalescence, which takes place via the lateral migration (drift) of superjogs driven by unbalanced line-tension partials acting on link segments of unequal lengths. Applied shear stress begins to push each link segment to precede dislocation multiplication when link length and jog height are greater than critical lengths. This dynamic dislocation multiplication source is subsequently verified by direct simulations of dislocation dynamics under stress to be crucial in the early stages of plastic deformation in Mo single crystals.
- Published through SciTech Connect.
International Conference on Computational Engineering and Science, Los Angeles, CA (US), 08/21/2000--08/25/2000.
Hsiung, L M; Lassila, D H.
- Funding Information:
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