Microstructural evolution in superplastic deformation of a Ti3Al alloy

The microstructural changes during superplastic deformation of a Ti3Al-Nb alloy were studied using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The dislocation generated during superplastic deformation formed more subgrains in the lath-like phase, producing low-angle boundaries and eventually high angle, showing that dynamic recrystallization did occur in these grains. When the angle of the boundary in a lath-like grain was large enough, the movability of the boundary increased so that the deformation could be processed by grain boundary sliding and migration.