Dynamic characterization of TiAl intermetallic in hot compression

In this paper the dynamic behaviour of TiAl intermetallic was studied experimentally by use of the Split Hopkinson Pressure Bar Technique. Cylindrical specimens 6 mm in height and 6 mm in diameter were dynamically compressed at temperatures ranging from 23 degrees C to 800 degrees C. Strain rates were about 2400 s(-1), except at room temperature, where strain rates ranging from 161 s(-1) to 3960 s(-1) were considered. The experimental results show that the TiAl intermetallic has a relatively high yield stress and a very large strain hardening capability throughout the temperature range studied. The compression behaviour was macroscopically ductile, and specimen failure was observed only at the highest temperatures tested, and at large strain values (near 0.35). An SEM observation of the fracture surfaces made evident a plastic shearing mechanism along the fracture planes accompanying crack formation.