Effects of temperature in range of 780 ℃ to 1 080 ℃ on the flow stress of the TC11 alloy have been tested by the Thermecmaster-Z thermo-analogue machine with strain rates of 10 s-1 and 70 s-1and on the microstructure have been observed.The results reveal that the steady flow characteristics can be observed during hot compressive deformation of TC11 alloy with the temperature in range of 990 ℃ to1 080 ℃

while the flow softening characteristics can be exhibited with the temperature in range of 780 ℃ to 960 ℃ at strain rates of 10 s-1 and 70 s-1.The microstructure observation shows that the TC11 alloy deformed in α+β phase zone exhibits adiabatic shearing or partial flow with temperature less than 900 ℃ at strain rates of 10 s-1 and 70 s-1.The microstructure of the alloy deformed in β phase zone consists of elongated β grain and minor dynamic recrystallization grain and show boundary deformation

which results in the mechanical instability of β phase.