Phase transitions and compression properties of Ti2AlC/TiAl composites fabricated by combustion synthesis reaction

Abstract The phase transitions in the Ti–Al and the Ti–Al–C systems are investigated by the differential thermal analysis (DTA) and X-ray diffraction (XRD). The results reveal that the addition of C not only leads to the formation of the Ti 2 AlC phase but also lowers the formation temperatures of the TiAl and Ti 3 Al phases. In the both systems, the combustion synthesis reactions are ignited at the melting point of Al, so the TiAl alloy and the Ti 2 AlC/TiAl composites are successfully fabricated at a lower temperature (about 660 °C) with an applied pressure. The yield strength, the ultimate compression strength and the work hardening rate of the Ti 2 AlC/TiAl composites are all higher than those of the TiAl alloy and increase with the increase in the Ti 2 AlC content. The average ultimate compression strength of the 6 vol.% Ti 2 AlC/TiAl composite is 179 MPa higher than that of the TiAl alloy without sacrificing ductility.