Hot deformation behavior of ZE42 magnesium alloy was investigated by compression tests at elevated temperatures in the range of 300

4

50℃and 0.01

1

0s

-1

respectively.Processing map was presented based on dynamic material model（DMM）at the strain rate of 0.35

0.40 and 0.45.The results reveal that average value of hot deformation apparent activation energy of ZE42 magnesium alloy reaches 151kJ/mol at experimental temperature range.The strain rate has significant effect on the processing map of the alloy.The alloy exhibits un-stability only in two tiny vicinities of 300 ℃

10s

-1

or320 ℃

0.01s

-1

.However

the instability areas are mainly distributed in the wide range of more than320 ℃

ε= 0.1

1.0s

-1

at strain of 0.35 and 0.45.The optimum hot working domain is presented as follows:350

450 ℃

ε≤ 0.1s

-1

with about 83% peak efficiency of power dissipation（ηmax）

and the main flow deformation mechanism is characterized by continuous dynamic recrystallization（DRX）cooperative with grain boundary sliding.