ABSTRACT

The interactions between dislocations and obstacles dictate the strengthening
of materials in a number of different settings. From a general perspective,
the theoretical treatment of such problems can be divided into two parts,
one involving the interaction between a single dislocation and a single
obstacle to its motion and the second involving the complex question of
statistical superposition of a multitude of such interactions, The aim of
the present work is to examine the nature of the interaction between
dislocations and second phase particles from the perspectives of both
atomic-level Simulation and elasticity theory. The role of partial
dislocations in governing the process whereby a dislocation passes an
obstacle is also examined. Our key finding can be summarized by noting
that as long as sufficient care is taken in constructing the elastic model
(i.e. including an appropriate line tension, including the presence of partial
dislocations, etc.), the results of atomic-level simulation and those emerging
from elasticity theory yield the same picture of dislocation-obstacle
interactions.