Directional solidification and microstructure selection for Ti-Al peritectic alloy

The examination on solidification characteristics of Ti-Al peritectic alloys was dealt with in both initial transient and steady state separately, the nucleation and constitutional supercooling of both phases at the solid/liquid interface and the effect of thermal gradient and growth velocity on the competitive growth of two phases were analyzed, and the condition of band structure formation and coupled growth was also determined. The composition range and G/v ratio to form the band structures were determined. The competitive growth between primary and peritectic phases was investigated during the initial transient and their development to steady-state growth for TiAl alloy, and the interface response functions were used to determine the selection map of phases and microstructures at different compositions and growth rates during the steady-state growth. The microstructures from directionally solidified TiAl alloys with given compositions were in good agreement with the predicted selection map.