By adopting four extrusion temperature

three extrusion ratio and three extrusion speed

effects of extrusion temperature and extrusion ratio as well as extrusion speed on the properties and microstructure of Gr.38 titanium alloy were investigated.The results reveal that the extrusion parameters have significant influence on the microstructure of Gr.38（ATI425）titanium alloy.With increasing in the extrusion temperature and extrusion ratio as well as extrusion speed

volume fraction ofαphase is decreased

and primaryαphase is recrystallized more fully

which is transformed from the distorted elongated shape gradually into spherical ones.Meanwhile

strength of the alloy is declined slightly with slightly rising of the elongation

which is attributed to more and more deformation thermal and deformation energy stored in the alloy resulting in the dynamic recovery and recrystallization.The optimized extrusion parameters of Gr.38 titanium alloy are presented as follows:extrusion temperature of 900

9

30℃

extrusion ratio of 14

1

8and extrusion speed of 70

8

0mm/s.