Extended Dislocation Configurations in HCP Silver–Tin Alloys of Low Stacking-Fault Energy

Configurations resulting from the interaction of extended dislocations in hcp silver–tin alloys of low stacking-fault energy have been studied by means of transmission electron microscopy. The interactions of all possible sets of two different extended dislocations are considered. Since there are two distinct modes by which dislocations extend in the hcp structure, these interactions fall into two classes: Class I interactions occur between two extended dislocations having the same fault shear vector; Class II interactions involve two extended dislocations having opposite fault shear vectors. Interactions between two arrays of extended dislocations lead to the formation of networks. Among the configurations studied were two different types each of dipoles, dipole networks, multipoles, and extended nodes. The observed configurations are compared to those reported in hexagonal graphite. The Class I configurations are similar to those found in low-stacking-fault-energy fcc metals.