An evaluation of high-temperature phase stability in the Ti–Al–Nb system

 Ti–Al–Nb alloys have shown promising properties for high-temperature applications. Although the phase diagram for this system has been well researched, there is still controversy over some aspects, including the extent of the β-phase field. We have studied an alloy with the composition 37Ti–44.5Al–18.5Nb, which based on existing phase diagrams is expected to solidify as the γ-TiAl phase. Experimental observations revealed that this alloy solidified as the β-phase, suggesting an extended β-phase field beyond the previously reported phase boundary.