The effects of different deformation conditions on the superplasticity of TB8 alloy and the microstructure evolution during deformation process were investigated. The results reveal that at 720 ～ 840 ℃ and 1. 0 × 10

-4

～1. 0 × 10

-3

s

-1

TB8 alloy exhibits the superplastic behavior. At 750 ℃ and 1. 0 × 10

-4

s

-1

elongation of the TB8 alloy reaches 524. 9%. During deformation process

the working hardening and the softening exhibits balance

and the alloy is characterized by the traditional steady-state superplastic flow behavior. Meanwhile

the deformation temperature

strain-rate and deformation rate have the significant effects on the microstructure. With decreasing in strain rate or increasing in tensile temperature

the size of the equiaxed β phase is increased.While with increasing in deformation temperature

α phase is dissolved into the matrix gradually and β phase tends to be saturated

however

the grains still retain in equiaxed state to some extent. The α phase segregated dispersedly from the grain boundary and matrix of β phase is increased with the deformation rate increase

which can inhibit the growth of grain size and improve the plasticity.