Deformation Mechanisms: Crystal Plasticity - Materials Science for Structural Geology - page 165

1500

673 K

703 K

1000

500

723 K

773 K

823 K

0

0 5 10

Strain / Percent

Fig. 6.21 Compression stress-strain curves for synthetic quartz crystal S1 under 300 MPa
confining pressure at various temperatures, showing yield drop phenomenon (After Fig. 4 in
Hobbs et al. 1972 , 352 pp)

v ¼ FM ¼ Dbls eff
kT

ð 6 : 38 Þ

(Brion et al. 1971 ; Burton 1982a ; Takeuchi and Argon 1976 , 1979 ; Weertman
1977 ). See (Poirier 1985 , p. 123) for a discussion on the appropriate choice of
diffusion coefficient D in applications to concentrated solid solutions. It should be
noted here, however, that there is a view (Kocks 1984 ) that solute drag is of
negligible importance at high temperatures and that the role of solute hardening is
effective through its influence on mutual dislocation interactions ( Sect. 6.6.6 ).