Temperature and velocity dependence of the mechanical properties of intermetallic compound Ni₃Al. II

Abstract

This paper examines the retardation of superdislocations in LI₂ superstructure, due to the capture by superpartial dislocations (SPD) of atomic defects on the slip plane, and also resulting from diffusion of atomic defects in PD. When the jogs formed by the settling of defects on dislocations remain nondissociated, the sliding of superdislocations is accompanied by the generation of displaced rows of atoms the maximum linear energy of which in the L1₂ superstructure amounts to v/b (v is the ordering energy, b the interatomic distance). The maximum magnitude of retardation of superdislocations, dependent upon generation of displaced rows, is twice as high on cubic planes as on octahedral planes. The estimations presented indicate that the diffusion settling of atomic defects on the SPD of sliding superdislocations can be a cause of the anomalous temperature dependence of flow stresses under high temperatures. Some effects associated with the possible dissociability of jogs on SPD are examined.