The influence of forging deformation degree and deformation temperature on microstructure and mechanical properties of titanium alloy forgings is interactive.

The deformation degree of titanium alloy forgings has an important effect on the high and low fold structure. When the deformation degree is greater than 

30%~ 40%, the microstructure of titanium forgings is obviously refined. In order to make the coarse acicular structure fully refined and transformed into spherical 

structure, the deformation temperature must be controlled within the two-phase zone, and the deformation degree should not be less than 60%~70%. The degree of 

deformation should ensure the formation of an intermediate structure between the acicular and equiaxial structures. The degree of plastic deformation at higher than 

the transition temperature should also be large enough to effectively refine the moon grain. In addition, the higher the deformation temperature, the greater the degree 

of deformation required.

If the titanium alloy forgings are plastic deformed in the (α 10 β) phase region before deformation in the β phase region, the microstructure can be refined as long as the 

deformation degree is not too large (30% to 40%). The reason is that the titanium alloy forged in the (α 10 β) phase zone reserves sufficient deformation energy and more

 dislocations, and then recrystallization occurs when deformed in the moon phase zone, making the deformation in the β phase zone more effective for the grain refinement 

of the alloy. However, the above effect of grain refinement is often not achieved in die forgings made above the monthly transition temperature. The reason is the large size 

of the die forging and the long time the metal stays at the temperature in the lunar phase zone. Especially in the hard-deformation zone of die forging parts, there is generally

 a coarse crystal structure, because these parts of the deformation degree is small, there is no recrystallization (β grain recrystallization), and the original grain has a violent growth.

The change of deformation degree not only affects the grain size, but also affects the intracrystalline acicular (sheet) structure. The increase of deformation degree will refine the

 intracrystalline structure. As with the influence of deformation temperature, the influence of deformation degree is most obvious at the temperature of the (α 10 β) phase region,

 because there is an α phase present, and the α phase undergoes plastic deformation.

The influence of deformation degree on mechanical properties, especially plasticity, is more significant at the temperature of (α 10 β) phase than at the α single phase region. The 

influence of deformation degree on mechanical properties decreases with the increase of deformation temperature.

For example, when TC6 alloy ingot is forged at a transition temperature higher than 3 (1050℃), with the increase of deformation degree, the low-power structure gradually becomes

 refined: when the deformation degree is 15%, the as-cast structure is not broken; When the deformation degree is 30%, the as-cast structure is slightly broken and slightly fibrous. 

When the deformation degree is 60%, it is obviously fibrous, but there is still a clear as-cast structure. When the deformation degree increased to 80%, it showed fine fibrous structure,

 but there were still traces of as-cast structure.