Deformation Behavior of Intermetallics: Models and Experiments

Abstract

AbstractA sufficiently general thermally activated mechanism for extension of dislocations in some preferential direction was proposed. This mechanism comprises a necessary step of dislocation transformations that lead to blocking. The reasons for blocking of different types of dislocations in different materials are diverse. A new concept was developed concerning the possibility of thermally activated blocking of superdislocations in the absence of external stresses. Some experiments with single crystals of Ni3(Al, Nb) were performed. They included no‐load heating after preliminary low‐ or high‐temperature deformation. It was found that the initial dislocation structure, which included curvilinear dislocations, transformed to a set of long rectilinear blocked superdislocations after no‐load heating. The experimental results confirmed theoretical assumptions on the possibility of thermally activated transformations of superdislocations to indestructible barriers in the absence of external stresses.