Prakt. Met. Sonderband 38 (2006) 229 
vhen the 
eps can 
dynamic 
density 
e harder 
s by a 
a phase 
se. 
ows the 
the load 
ind 80% . 
ion was ‘ - 20m py [ 20m 
w 0.6 of 
23°. an ; 
ture and 
Fig. 9. Comparison of the microstructures at 
768°C: a) phase equilibrium before 
deformation, b) after deformation at 0.01 s™ 
and 0.7 true strain in the centre of the 
sample showing some globularization and 
. separation and c) after deformation at 1 s™ 
haan and 0.7 true strain in the centre of the 
3 sample showing elongation of the alpha 
i particles. Compression axis is vertical. 
—— ‘ 20um 
0.01s 
1s” 
16 18 4. CONCLUSIONS 
ed load. Two main processes change the morphology of the alpha phase during deformation below 
entation beta transus temperature: diffusion process separates and coarsens the alpha grains at 
low strain rate. At 1s”, the alpha grains become squeezed and elongated due to the 
dislocation glide/climb deformation process. 
SCIMENS During the deformation the alpha phase takes a preferential orientation almost 
eformed perpendicular to the compression axis. 
globular An effect of the strain rate on the beta sub-grains was observed: they increase at 0.01s™ 
ongated due to dynamic recovery. At 1s” of strain rate. refinement of the beta sub-grains results 
during compression. 
5. ACKNOWLEDGMENTS 
This work was carried out within the project “Modelling of microstructure and 
microstructure-dependent mechanical properties of near beta titanium alloys” sponsored 
by the Austrian Aeronautic programme “TAKE OFF” and Béhler Schmiedetechnik GmbH & 
Co KG, Kapfenberg, Austria.