Reconciliation of atomic-level and continuum notions concerning the interaction of dislocations and obstacles

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. (C) 2001 Elsevier Science Ltd. All rights reserved.