As-cast microstructure of Mg-7Gd-5Y-1.2Nd-Zr magnesium alloy was observed

and the mechanical behavior of the alloy during hot deformation process was examined on the Gleeble-1500D hot simulator with reduction of 60% and strain rates of 0.002

0.01

0.1

1 s-1 at 573～723K.As-cast microstructure of the alloy is composed of α-Mg phase and net-like eutectic phase.At a given temperature

the peak stress is increased with increasing in strain rate;while with a given strain rate

it is decreased with increasing in deformation temperature.Softening of eutectic phase in microstructure of the alloy plays an important roles in decreasing in peaking stress at high temperatures.Discontinuous recrystallization in the alloy is more distinct at strain rate of 0.1 s-1

resulting in the failure of alloy.Average deformation activation energy and stress exponent are 243.5kJ/mol and 4.1972

respectively.The deformation activation energy is related directly to deformation temperature and related indirectly to strain rate.