Experiments were performed which revealed that heating in the absence of an external stress after a preliminary both low-temperature and high-temperature deformation of intermetallic compounds led to a fundamental change in their dislocation structure. For the investigation, [251] single crystals of Ni3(Al,Nb) were used. The low-temperature deformation was performed at −196C, and the high-temperature deformation at 800C. It was found that the initial dislocation structure consisting of curvilinear dislocations was changed upon heating without a load by a set of rectilinear blocked dislocations. It was shown that upon heating after a preliminary low-temperature deformation the barriers present in the structure belong to the cubic cross-slip plane, whereas upon heating after high-temperature deformation, to primary cubic slip planes. It was found that the decisive effect on the blocking of super-dislocations upon heating without stress comes from one of the dislocations that compose the super-dislocation, namely, either a super-partial dislocation in the case of low-temperature deformation or a simple partial dislocation in the case of high-temperature deformation. The concept of the possibility of thermo-activated blocking of super-dislocations in the absence of external stresses was confirmed experimentally.

Some Features of the Formation and Destruction of Dislocation Barriers in Intermetallic Compounds – II - Observation of Blocked super-dislocations upon Heating without Stress. B.A.Greenberg, O.V.Antonova, M.A.Ivanov, A.M.Patselov, A.V.Plotnikov: The Physics of Metals and Metallography, 2006, 102[1], 69-75