In this talk, a plausible form of the hardening relations for single
crystals is presented. The theory is based on: i) the motion of a dislocation
line through forest dislocations; ii) the short-range interactions between
pairs of dislocations and the strength of the resulting intersections viewed as
point obstacles, and iii) the kinetics of dislocation multiplication.
three-dimensional near-tip fields are characterized numerically. For comparison
purposes, the corresponding plane-strain field are also computed numerically
and their asymptotic behavior determined semi-analytically. On the basis of
these analyses, we investigate: i) the dependence of the fields on the
hardening law; ii) the degree of correlation between surface and interior
fields in finite specimens; and iii) the degree of correlation between
plane-strain and three-dimensional fields.
Finally, a time-dependent
deformation mechanism for FCC metal single crystals in which the resulting
deformation is produced by the cumulative effect of dislocation glide in each
slip systems is introduced. This model presents a self-consistent
micromechanical approach where both the time-dependent and independent
deformation are linked together.