Rapid Growth of TiNi intermetallic compound within undercooled Ti50Ni50 alloy under electrostatic levitation condition

•Growth kinetics of primary TiNi phase is detailed analyzed.•Precipitates on the grain boundary are changed with the enhancement of undercooling.•Intermediate phase (R-phase) of martensitic transformation is detected in TiNi phase at large undercooling.•Three different solidification modes of Ti50Ni50 alloy is sufficiently elucidated.