Prakt. Met. Sonderband 38 (2006) 49 
of MDRX If MDRX and SRX are in competition, well developed MDRX grains besides possible SRX 
perature. nucleation sites can be observed shortly after the deformation (after 1s of dwell time in 
, but only Fig. 7). The latter, similar to the formation of new DRX strands described above, can be 
whereas identified by large subgrains, whose boundaries eventually will be transformed into high 
e place if angle grain boundaries. The size of these subgrains approximately corresponds to the 
and soak predicted final SRX grain size. Whether such SRX nuclei can become stable depends on 
SRX. The the degree of completion of MDRX as well as on the distribution of the MDRX grains. 
. 6. For a Besides the specimens those microstructures are shown in Fig. 6 additional specimens 
raction of were investigated and an overview of the results is given in Fig. 8. The left diagram clearly 
the pre- indicates that in the pre-strain range investigated, the major part of the recrystallized 
grains is grains is caused by SRX. Only for pre-strains higher than 0.17 a noticeable contribution of 
ystallized DRX and MDRX can be observed. At very low strain (0.07), where no DRX and MDRX can 
take place, a strong dependence of the recrystallized fraction on the soak time was found 
with a value of more than 80% increasing the soak time up to 100s. But it is not clear 
whether this recrystallized fraction is obtained due to grains caused by SRX or due to the 
recovery of the deformed grains. With the grain orientation spread it is not possible to 
differentiate between SRX and recovery, because grains with very low orientation spread 
arise from both processes. The strong increase of the size of recrystallized grains by 
increasing the soak time and that after 100s this size is in the range of the initial grain size 
indicates a predomination of the recovery process. The dependence of the grain size on 
the pre-strain and the soak time is depicted in Fig. 8b. This diagram also shows that the 
pre-strain only slightliy influences the size of the recrystallized grains. 
od = # Rt 
0.8 --¥ 80 hs Ea wie : ee 
a —e-soskimets a TUT 
0.5 —#— soak time 10s 2 
04 nn Mo 
„3 3 Anse ETI 
wo 0.1 - ET mh Hx 10 Yaris . 
rE... (a En 
0.05 010 015 020 025 0.30 005 010 0.15 0.20 025 0.30 
and two pre - strain pre - strain 
ed). Fig. 8: a) Recrystallized fraction as a function of pre-strain b) Average diameter of the 
recrystallized grains as a function of the pre-strain (all twins removed) 
4. SUMMARY 
The recrystallization behaviour of the nickel based alloy 80A was investigated by electron 
backscatter diffraction by analyzing the grain orientation spread to discriminate between 
the recrystallized and the deformed grains. A nearly linear increase of recrystallized 
fraction was observed for the dynamic recrystallization process in dependence on the 
strain. The calculated grain size strongly depends on the handling of the twins. A 
significant increase of the grain size was only observed if all twins had been removed. 
all angle Grains caused by the static recrystallization process were also strongly twinned, but they 
g MDRX did not show a size increase with increasing pre-strain. In contrary to the grain size a 
le SRX strong influence of the recrystallized fraction on the pre-strain and the .soak time was 
32um (a) observed.