The equal channel angular pressing （ECAP） for 7075aluminum alloy was simulated with different friction factors using the finite element software DEFORM-3D.The pressing load

deformation rate as well as effective stress and strain distribution were analyzed

and the change of microstructure of7075aluminum alloy during ECAP was predicted using the dynamic recrystallization model.The results show that

with the increase of the friction factor

the peak load is significantly increased and even grow exponentially accompanying with the sharp fluctuation of load.Besides

the"end effect"of sample is weakened and the effective stress and strain distribution exhibit uneven.The grains of the stable deformation zone in the central of sample are constantly refined with the extrusion passes increases

and the fine grain area is generated in the sample contact with the channel.In addition

the grains of the stable deformation zone with frictional coeffiaent of 0.4are finer than those with 0.1after four passes extrusion.