Pulse current was applied to the solidification process of directionally solidified Ti-45.5 Al-4 Cr-2.5 Nb alloy. The effects of different pulse frequencies on the solidification microstructure and properties of TiAl-based alloy were investigated. The results indicate that when the pulse current density is 52.9 mA/mm~2

the lateral heat dissipation and the average deviation angle of dendrites are decreased with the increase of pulse frequency due to the skin effect and Joule heat effect of current. However

with the further increase of pulse frequency

the Lorentz force is increased

and the branch crystal is broken or remelted by electromagnetic stirring

resulting in the increase of grain deviation angle. The average width of grain is firstly increased and then reduced with the increase of pulse frequency. When the pulse current frequency is lower

the dendrites are remelted or broken due to the Joule heat effect of current and electromagnetic stirring. The length of melting zone is increased and temperature gradient is decreased

leading to the increase of average grain width instead. With the continuous increase of pulse frequency

Lorentz force is increased

and strong electromagnetic stirring can refine grains

resulting in the average width reduction of grains. Compared with the master alloy ingot

the tensile strength of TiAl alloy is increased by 70.7% under pulse current

and the elongation is increased by 129.5%.