A study of dislocation junctions in FCC metals by an orientation dependent line tension model

摘要

The formation and strength of dislocation junctions in FCC crystals have been calculated using an orientation-dependent line tension model. The structure of the different types of junctions existing in FCC metals in the absence of an applied stress is examined with particular emphasis on the Lomer-Cottrell lock, the Hirth lock and the glissile junction. We have determined the 'yield surface' in stress space corresponding to the dissolution of junctions. Although this model represents a huge simplification of the physics of dislocations, the comparison with more sophisticated models shows that it is able to satisfactorily reproduce both the structure of junctions as well as their response to an applied stress. Moreover, it is in qualitative agreement with available experimental data. It is claimed that this simple model can provide useful parameters related to junction strength in higher level models of single crystal plasticity.