THE PHASE-TRANSFORMATIONS IN ALLOYS BASED ON TITANIUM ALUMINIDES TI3AL-V AND TIAL-V

Vanadium is an element of interest in terms of improving the mechanical properties of Ti3Al (alpha-2) and TiAl (gamma). Therefore, it is important to study the phase equilibria between titanium, aluminium and vanadium. Titanium alloys of compositions 10.5-57 wt.% Al and 4-51 wt.% V were prepared and then heat treated at temperatures of 1473, 1173, 1073, 973 and 873 K. The microstructures were identified by using conventional techniques. The compositions of the identified phases in the bulk and thin foil samples were determined by microprobe analysis. Five isothermal sections of Ti-Al-V ternary diagram were established at these temperatures. The effect of the oxygen content of alloys on the phase boundaries of alpha, beta and gamma-phases was also determined at 1473 K.