An evaluative approach to correlate machinability, microstructures, and material properties of gamma titanium aluminides

Several generations of gamma titanium aluminides have been developed over time, and they are nowadays commercially available. The differences in chemical composition, as well as the thermal treatments, greatly influence the properties of the alloys. This implies considerable effects on the production process performances. Benchmark trials were performed on three γ-TiAl alloys: Ti-48Al-2Cr-2Nb, Ti-43.5Al-4Nb-1Mo-0.1B, and Ti-45Al-2Nb-2Mn + 0.8 vol.% TiB2 XD, focusing on machinability and material characterization. The extremely dissimilar results obtained when turning and milling can be traced back to the different microstructures, as well as to the alloying elements, factors both affecting the mechanical and thermal material properties.