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SUMMARY:High-Temperature Discrete Dislocation Plasticity
DTSTART:20120403T131500
DTEND:20120403T141500
DTSTAMP:20260407T175647Z
UID:c9e87f183b27694a2db22209bbca0ed756dba31b8553b3f44407916b
CATEGORIES:Conferences - Seminars
DESCRIPTION:Dr. Amine Benzerga\, Texas A&M University\, USA\nAt low homolo
 gous temperatures\, the plastic deformation of metals is controlled by the
  glide of dislocations and a host of athermal interactions with other disl
 ocations\, precipitates and grain boundaries. In discrete dislocation dyna
 mics simulations of such deformation processes\, temperature effects may e
 nter through dislocation mobility and lattice friction as well as cross-sl
 ip. At temperatures greater than about 1/3 of the melting point\, the clim
 b of dislocations becomes increasingly important leading to phenomena such
  as creep and dynamic recovery. The modeling of climb as a nonconservative
  motion generally requires the concurrent modeling of dislocation motion a
 nd the diffusion of point defects into the cores of the dislocations. In t
 his paper we report on a self-consistent formulation of high-temperature d
 iscrete dislocation plasticity in finite bodies\, which couples dislocatio
 n dynamics with vacancy diffusion theory. To address the issue of disparat
 e time scales related to glide and climb mechanisms\, an adaptive multi-ti
 me stepping algorithm is used in the numerical implementation of the theor
 y. We then present a series of deformation analyses at constant applied st
 ress in single crystals. We show that two regimes of power-law creep natur
 ally emerge in the simulations\, as affected by the applied stress and tes
 t temperature. We also systematically quantify the power law exponent in e
 ither regime and the part of the strain rate that results from mass transp
 ort through the diffusive flow of vacancies due to pressure gradients
LOCATION:ME B3 31 http://plan.epfl.ch/?lang=fr&room=me+b331
STATUS:CONFIRMED
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