Civil Engineering Reference
In-Depth Information
Fig. 11.41
EAM force
reduction and elongation
increase [
20
,
21
]. The
application of electrical
pulses (i.e., the steep drop-
offs in the EAM profile)
proved to reduce the overall
engineering stress-elongation
profile and increase
elongation compared to the
non-pulsed baseline test
Fig. 11.42
Diffuse necking
effect (baseline vs. EAM)
[
20
,
21
]. The two EAM tests
produced much more defined
diffuse necks than the non-
EAM baseline test
current density and pulse duration, which allows accurate elongation predictions
to be made from respective parameter combinations (Fig.
11.43
). This relation-
ship could also be represented in 3-D as a “formability ridge,” specifying expected
elongation for different current density and pulse duration combinations, as shown
in Fig.
11.44
.
Conclusions from this section are as follows:
• EAM produced the most optimum formability improvements with high cur-
rent density/short pulse duration and low current density/long pulse duration
combinations.
• In cases where this inverse relationship was violated, such as low current/short
duration, the formability remained unchanged.
