Strain-Induced Disruption of Long-Range Order due to Generation of Superdislocations in L12-Superlattice Alloys

A disruption mechanism for the long-range atomic order in alloys with the L1₂ superlattice is examined. The disruption is caused by an accumulation of superdislocations upon plastic deformation. The rate of increase of the antiphase-boundary area resulting from multiplication of superdislocations is estimated for the cases where the spacing between superpartial dislocations is either constant or strain-dependent. Equations are derived for the rate of change of the degree of long-range order as single-crystalline L1₂-superlattice alloys are subject to deformation.