Interactions between edge lattice dislocations and Sigma 11 symmetrical tilt grain boundaries in copper: A quasi-continuum method study
W. S. Yu and Z. Q. Wang
Acta Materialia, 60, 5010-5021 (2012).
ABSTRACT
"Positive" and "negative" interactions between specified numbers of piled-up
lattice dislocations and (+)Sigma 11((3) over bar 1 (1) over bar) and (-)Sigma
11 ((1) over bar 3 1) symmetrical tilt grain boundaries in two bi-grain models
of copper have been studied using the quasi-continuum method. The mechanisms of
both interactions in representative loading stages are analyzed in terms of the
evolution of grain boundary (GB) configurations and Burgers vector conservation.
A unified geometrical criterion is proposed to predict "hard" and "easy"
dislocation transmission without explicitly defining the "positive" and
"negative" dislocation/GB interactions. The pile-up of incoming dislocations has
a remarkable influence on both "positive" and "negative" interactions, and can
activate dislocation transmission at smaller external loadings. Critical stress
analysis for relatively easier dislocation transmission in "negative"
interactions reveals that they depend on the ratio of total shear stresses on
the incoming and outgoing slip planes and the ratio of total normal and shear
stresses on the outgoing slip plane. An analysis of the Burgers vectors of
residuals produced from dislocation/GB interactions shows that GBs impeding
dislocation motion have larger residual values.