Evolution of Solidification Structures in Fe-Mn-Si-Cr Shape Memory Alloy in Centrifugal Casting

In aiming at obtaining thin columnar structures in the centrifugal casting of Fe-28Mn-6Si-5Cr (mass%) shape memory alloy (SMA), evolution of solidified macroscopic structures is investigated by solidification experiments and simulation using a coupled finite volume-cellular automaton (FV-CA) model. In the temperature gradient-crystal growth rate (G-V) diagram of solidification, the columnar to equi-axed transition (CET) line that indicates the boundary of two different structural regions is identified from the simulation calculation. The macroscopic structure of joining pipes of Fe-28Mn-6Si-5Cr SMA produced by centrifugal casting is elucidated to reside in a deep region of columnar structure in the G-V diagram. It is concluded that finer columnar structure could be obtained by increasing the rotation speed of centrifugal casting mould and by increasing the cooling rate of the casting.