Abstract
The compressive behaviors at strain rates from 4x10-6 to 1x10-2 s-1 at temperatures from 1373 to 1448 K were characterized to investigate the influence of grain size for powder metallurgically processed TiAI intermetallics with fine grained structures of about 18 μm in size and ingot metallurgically processed TiA1 with coarse grained structures of about 380μm. For coarse and fine grained intermetallics of TiA1 at higher stresses, stress exponent of about 4 is found and the rate controlling deformation may be a diffusion controlled dislocation process. At intermediate stresses for the fine grained TiA1, a stress exponent of about 2 is found, and the rate controlling deformation is proposed to be grain boundary sliding. In two different grained intermetallics, furthermore, the measured activation energy from 343 to 370 kJ/mol is obtained.
