The influence of electric pulse（EP）current with frequency of 20

50 and 150 Hz as well as the current density of 400 Aon the microstructure and mechanical properties of Al-Zn-Mg-Cu rolled plate was investigated during solidification process.The results indicate that the macro-segregation degree is greatly improved and the microstructure is obviously refined with 20 Hz EP field.Instead

the structure entirely made up of dendrites has hardly any change at 150 Hz.τphases in form of network or island are widely distributed in aluminum alloy.Meanwhile

the tensile strength of cast rolling strips modified by 20 Hz EP current can reach 320 MPa

which is1.3 times of that of conventional ones.The strips are characterized by brittle fracture

and the ductility is increased after modified by EP current.