Civil Engineering Reference
In-Depth Information
Fig. 8.27
Microstructure of
continuous EAF (150 A) test
(sample 12) in orientation
1 at L2
Fig. 8.28
Microstructure of
continuous EAF (150 A) test
(sample 11) in orientation
1 at L1
and strain response of the test is suggestive of dynamic recrystallization due to
the decreasing stress response after a peak stress is reached. This type of behavior
has been noted in works performing elevated temperature forming of magnesium
[
10
,
11
]. The difference is that the temperature rise is a result of Joule heating
within the material as compared to external heating in a chamber. Also, unlike
external heating methods, a temperature gradient is present along the length of the
specimen. Consequently, this allows for a variation in deformation behavior along
the specimen length which corresponds to the observed variation in microstruc-
ture. The localized deformation behavior is illustrated in Fig.
8.30
where there is
an extreme amount of localized deformation at L1. From a visual perspective, it
appears that L3 and L2 only have a small amount of deformation and the defor-
mation is concentrated at L1. Also, it appears that dynamic recrystallization has
