FORMATION OF SUBMICROCRYSTALLINE STRUCTURE IN TIAL INTERMETALLIC COMPOUND

The TiAl intermetallic compound was used to illustrate an approach which enables the creation of a submicrocrystalline structure (d congruent-to 0.1-mu-m) in massive semifinished products made of hard-to-deform materials by means of their deformation at elevated temperatures. Tensile mechanical properties of the TiAl intermetallic compound with a mean grain size of 0.4-mu-m were tested. In this state, the lower temperature limit of superplasticity in TiAl was found to be 800-degrees-C. At this temperature and at an initial strain rate of 8.3 x 10(-4) s-1, the relative elongation to rupture attains 225%.