ICAMS / Interdisciplinary Centre for Advanced Materials Simulation


Why is the slip direction in CuZn and FeAl different than in CoTi?

V. Paidar, Y.-S. Lin, M. Čák, V. Vitek.

Intermetallics, 18, 1285-1287, (2010)

The slip system in FeAl at low temperatures is <111>{110}. However, while in B2 compounds the slip plane is {110}, the slip direction is often <001> which is the shortest lattice vector in this structure. Differences among various B2 systems are obviously rooted in the nature of chemical bonds and it has often been assumed that it is the antiphase boundary energy that dictates the choice of the slip system. However, it is shown in this paper by comparing the three compounds CuZn, FeAl and CoTi that factors governing the choice of the slip direction are more varied. They are, in particular the elastic anisotropy, types of planar faults on {110} planes with which dislocations can dissociate and the energy of these faults that is not simply related to the order–disorder transition temperature. Analysis taking into account all these factors explains then different slip directions in FeAl and CoTi that have similar order–disorder transition temperatures and shows why in FeAl the slip system is the same as in CuZn.

Keyword(s): aluminides; mechanical properties; theory; superdislocations
DOI: doi:10.1016/j.intermet.2009.11.015
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