Effect of Mo addition on transformation behavior of (α2 + γ) based Ti–Al alloys

The structural and microstructural characterizations of four alloys with nominal compositions of Ti–42Al–2Mo, Ti–42Al–6Mo, Ti–40Al–2Mo, and Ti–40Al–6Mo have been studied. The 2 at.% Mo as cast alloys comprise of (α2 + γ) phases whereas those of 6 at.% Mo show (B2 + γ) phases. The solution treatment at 1300 and 1400 °C for 1 h followed by water quenching of these alloys have shown composition specific phase transformation characteristics. The formation of the B2 phase during heat treatment has been discussed and structural model based on statistical occupancy to explain (1 0 0) peak will be presented. The change in the nature of bonding of the B2 phases in Ti–Al–M (M = Mo, Nb, V) alloys have been highlighted.