Abstract:The samples of TiAl-3Ta-x(Cr,W)(at%) were hot compressed by Gleeble-3800 in the temperature range of 1150~1300℃ from 0.1~1s-1 for high temperature fracture behavior and microstructure evolution study. The results show that the main fracture modes consist of 45° shear fracture and longitudinal fracture on free-surface, but which crack location is different. Moreover, the cracking degree increased with the decreasing of deformation temperature, the increasing of strain rate and height reduction.In the high strain rate range, deformation twinning dominated the entire deformation process.Morever, the cracks nucleation sites were observed at grain boundary of the colonies and/or interfaces between lamellae of the specimens, and initiate and propagate perpendicular to the compression axis.