Transition of solidification path in nonequilibrium solidification of Ti–48Al–8Nb alloy

The solidification behavior of Ti–48Al–8Nb alloy under nonequilibrium solidification conditions was studied by electromagnetic levitation technique. The solidification conditions are different undercooling (ΔT) under the same cooling condition and different cooling methods at the same undercooling condition, respectively. In different undercooling conditions, when the undercooling is above a critical value (ΔT* ≈ 211 K), a remarkable morphological transition from typical hypoperitectic solidification to a sole solidification of the β phase resulting in the suppression of the peritectic reaction occurs. For melts with different cooling conditions at the same undercooling (ΔT ≈ 85 K), the melt was rapidly cooled by quenching them in cooling media. With cooling rate increasing, a transition from β phase to peritectic α phase solidification mode is revealed for Ti–48Al–8Nb alloy.