Physicochemical Interaction in the TiAl–Nb/V Systems during Aluminothermic Synthesis

The sequence of intermetallic compound formation during the aluminothermic co-reduction of titanium, vanadium, and niobium from their oxides in Ti–Al–Nb and Ti–Al–V alloys is considered. The structure of the titanium–aluminum–rare metal alloys formed during metallothermic synthesis is studied. In recent years, interest in TiAl alloys with more than 40 wt % Al has grown. These alloys have a lower density and higher corrosion resistance at elevated temperatures compared to low-aluminum alloys due to the formation of an oxide layer on the surface. In addition, earlier studies detected the formation of the Al₂Ti intermetallic phase, which also positively influences the corrosion properties of TiAl alloys. Aluminothermic synthesis can be one of the methods for producing such alloys. This method of producing TiAl alloys can be effective to extract pure metals from their oxides. However, successful implementation of this process requires more detailed studies on the phase composition, structure, and the sequence of intermetallic phase formation in the alloys under study. To find the sequence of intermetallic compound formation during the reduction of metals from their oxides in the Ti–Al–Nb and Ti–Al–V systems, we performed differential thermal analysis (DTA) and X-ray diffraction analysis (XRD) of the initial components using an STA 449 F3 Jupiter (NETZSCH) device and an XRD-7000 (Shimadzu) diffractometer. Metallothermic synthesis was carried out in laboratory resistance furnaces at 1600°C. The microstructure of the alloys after metallothermic melting was investigated by electron probe microanalysis with a Carl Zeiss EVO 40 (Germany) scanning electron microscope equipped with an Oxford Instruments INCA X-Act (Great Britain) energy dispersive X-ray detector.