Theoretical Analysis of Plastic Deformation in Superlattices Based on the Body-Centered Cubic Structure

Abstract

A theoretical analysis has been made of the friction stress opposing the movement of both superlattice slip dislocations and twinning dislocations which arises from their interaction with antiphase domains in B2-, DO3-, and L21-type superlattices, all of which are based on the body-centered cubic structure. In the case of superlattice slip dislocations, this interaction results in the well-known maximum in yield stress at some critical antiphase domain size. Twinning dislocations, on the other hand, require stress levels about twenty times greater than the maximum value calculated for superlattice dislocations; however, this friction stress decreases for domains smaller than the critical size. In both DO2- and L21-type superlattices, second nearest neighbor as well as first nearest-neighbor ordering energies are found to play an important role in the resistance to dislocation motion. These results agree well with the limited number of experimental observations obtained by other investigators with the Fe3Al superlattices.