Hochverformung von intermetallischen γ-Titanaluminiden

In the past 20 years there has been a great emphasis placed on developing intermetallic γ-titaniumaluminides (TiAl) because of their outstanding high temperature properties. These TiAl alloys are supposed to replace nickel-based superalloys in their applications. Since the plastic deformation of these materials at room temperature is rather limited, the deformation behavior at room temperatures using high-pressure torsion was investigated in the present work. Subsequently, the effect of high strain on microstructure and mechanical properties of two- and three-phase intermetallic γ-TiAl-based alloys, in particular TNM alloys, was investigated. From the results of SEM, XRD and nano-hardness tests a partial disordering of the ordered phases can be assumed. Moreover, the deformation by HPT has a significant effect on the volume fraction of the βo-phase. It was found that the volume phase fraction decreases with increasing degree of deformation.