DISLOCATION BEHAVIOR IN THE SUPERPLASTIC DEFORMATION OF ALLOY Al-Li 2091

The dislocation behavior in the superplastic deformation of alloy Al-Li 2091 has been studied. Both TEM observation and x-ray diffraction analysis revealed that: in the studied range of strain, the amount of dislocation in the grain interior decreases with the increase of strain. There also exist such dislocation configurations as network, subgrain boundaries, dislocation poles, helical dislocation, dislocation ring and grain boundry dislocations. In the softening stage of superplastic deformation, with the increase of strain, the velocity of dislocation motion increases and the activation energy of dislocations decreases.