Dislocations in a crystal are usually classified into several independent slip systems. Motion of a partial dislocation in monometallic crystals may remove or create stacking fault characterized with a partial of a lattice translation vector. However, it is recently known that motion of partial dislocations in complex structure, such as that inside an intermetallic Al2Cu compound, lead to a local composition deviation from its stoichiometric ratio and the resultant structure collapse. Here we report such a local decomposition behaviors are strongly dependent on slip system of dislocations. Under applied external stress, we have studied dislocation motion behaviors in the three independent slip systems of (110), (0 (1) over bar0) and (1 (1) over bar0) within tetragonal Al2Cu crystal by using molecular dynamics method. We found dislocation motions in all these slip systems result in local decomposition but their physical details differ significantly.
; ma, x. l.] chinese acad sci, shenyang natl lab mat sci, inst met res, shenyang 110016, peoples r china.
; ma, xl (reprint author), chinese acad sci, shenyang natl lab mat sci, inst met res, wenhua rd 72, shenyang 110016, peoples r china.