Deformation Behavior of a β-Solidifying TiAl Alloy within β Phase Field and Its Effect on the β→α Transformation

In this study, the deformation behavior of a Ti-40Al-10V (at.%) alloy within &beta
single phase field was examined by means of isothermal compression at 1300 &deg
C under strain rates of 2 s&minus
1, 0.2 s&minus
1, and 0.02 s&minus
1, as well as its effect on the subsequent &beta
&rarr
&alpha
transformation. The results showed that the alloy behaved steady-state flow with dislocation creep as the predominant rate-controlling process. Dynamic recrystallization (DRX) evidently occurred during deformation, and its volume fraction was dramatically increased so that at the lowest strain rate (0.02 s&minus
1), a full-DRX &beta
structure was obtained. The preferentially dynamic migration of grain boundaries with &lt
100&gt
orientation was demonstrated to be the major DRX mechanism. The texture was characterized by a &lt
+ &lt
111&gt
double-fiber at 2 s&minus
1, but gradually transformed into a simple rotated cube orientationunder 0.02 s&minus
1, accompanied by a decreasing texture intensity. During the subsequent &beta
transformation, two types of &alpha
morphology wereproduced with evident variant selection, namely, the Widmannstatten colony and martensitic laths. Texture simulation revealed that the &alpha
texture was solely determined by parent &beta
texture, despite of the variant selections.