Civil Engineering Reference
In-Depth Information
Fig. 11.40
Experimental EAM setup [
20
,
21
]. This EAM testing setup includes conductive
metal dies with rigid insulation materials placed in between the dies and the testing machine, to
ensure that the electricity only flows through the workpiece
Figures
11.41
and
11.42
display the general force reductions, elongation improve-
ments, and diffuse necking effects compared to the non-pulsed baseline tests.
The conclusions from this work are as follows:
• The effectiveness of the pulsed electricity is dependent on both the alloy and its
heat treatment.
• The size of the diffuse neck resulting from electrical pulsing was found to be
irrespective of the material pulsed, but dependent on the parameter set used for
pulsing.
• In any aluminum alloy/heat treatment combination, the greater pulsing fre-
quency of Parameter Set 2 developed a larger diffuse neck compared to the
greater magnitude of pulses in Parameter Set 1.
• The formability of both aluminum alloys was improved by EAM, but Al5083
had the greatest elongation increases and flow stress reductions due to EAM.
11.4.2.4 Effects of Electrical Application Parameters on Formability
Improvements
This research work explored the effects of particular EAM pulsing parameters
(current density and pulse duration) on the formability of Mg AZ31B-O speci-
mens undergoing uniaxial tensile deformation [
22
]. As a part of investigating
these effects, various current density and pulse duration combinations (i.e., high
current/short duration or low current/long duration) are examined. An important
outcome of this work was the development of a linear inverse relationship between
