Aj. Beaudoin et A. Acharya, A model for rate-dependent flow of metal polycrystals based on the slip plane lattice incompatibility, MAT SCI E A, 309, 2001, pp. 411-415
A constitutive framework that considers rate-dependent deformation and grai
n-size dependent work hardening of FCC and BCC metals at moderate temperatu
re is proposed. This model considers 3-D polycrystalline aggregates of visc
oplastic crystals. The hardening response of the individual single crystals
is considered to be isotropic (Taylor model), but modified to include a ph
ysically-motivated measure of slip plane lattice incompatibility. In the co
ntinuum setting, a density of net dislocations is derived from the lattice
incompatibility. The association of a mean free path (that distance a dislo
cation can move before unit length is stored) with the net dislocation dens
ity is introduced into the evolution equation for hardening. Application is
made to grain-size effect in work hardening, nanoindentation, and the tran
sition from stage III (parabolic) to stage IV (linear) hardening. (C) 2001
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