Detailed atomic structure of arbitrary fcc [100] twist grain boundaries

Abstract

The generalized coincidence site network model has been applied to the study of fcc twist @100# grain boundaries. The result has been the detailed atomistic description of general ~100! twist grain boundaries, supported by a set of quantitative expressions obtained directly from the model’s hypotheses concerning primary and secondary dislocation spacings and Burgers vectors; these are in complete agreement with both accepted theory and experimental observations. According to the model, singular boundaries, defined as those boundaries containing only one primary dislocation per coincidence site lattice unit cell, are proposed to be composed of atomic domains with the structure of S1, separated by an array of perfect primary dislocations. Every random boundary has an associated singular boundary and its structure consists of a mixture of domains found in the associated boundary, in different translational states; these domains are in turn separated by an array of partial secondary dislocations. A nonsingular boundary therefore contains arrays of both primary and secondary dislocations. @S0163-1829~99!07803-0#