The influences of pulse electric currents at energy density levels of 0.105 J/mm3 and 0.150 J/mm3 on AA5754's flow stress and elongation are investigated. Different combinations of current density and pulse duration are carried out for each energy density. The non-Joule heating effects in electrically assisted forming (EAF) are revealed since the temperatures generated by the electric currents of the same energy density are identical. It is observed that a pulse current helps reduce AA5754's flow stress and increase its elongation. At the same level of energy density, as the current density increases, the instant drop of stress increases as well as the elongation, although the maximum flow stress remains almost unchanged. A theoretical model is proposed that can predict the stress drop during electrically assisted forming. The fracture surfaces of AA5754 subject to pulse currents are observed and analyzed. The dimples of fracture continue to decrease until they completely disappear as the density of pulse current increases. The suppression of voids nucleation and growth by a pulse current leads to the increase of total elongation.

References

1.
Wang
,
H.
,
Luo
,
Y. B.
,
Friedman
,
P.
,
Chen
,
M. H.
, and
Gao
,
L.
,
2012
, “
Warm Forming Behavior of High Strength Aluminum Alloy AA7075
,”
Trans. Nonferrous Met. Soc. China
,
22
(
1
), pp.
1
7
.
2.
Ozturk
,
F.
,
Toros
,
S.
, and
Pekel
,
H.
,
2009
, “
Evaluation of Tensile Behavior of 5754 Aluminum–Magnesium Alloy at Cold and Warm Temperatures
,”
Mater. Sci. Technol.
,
25
(
7
), pp.
919
924
.
3.
Cao
,
L. Y.
,
Guo
,
M. X.
,
Cui
,
H.
,
Cai
,
Y. H.
,
Wang
,
X. F.
, and
Zhuang
,
L. Z.
,
2013
, “
Study on Mechanical Properties and Texture of 6111 Aluminum Alloy Sheet in Automotive Industry
,”
Trans. Mater. Heat Treat.
,
34
(
7
), pp.
118
123
(in Chinese).
4.
Zhao
,
K. M.
, and
Lee
,
J. K.
,
2001
, “
Material Properties of Aluminum Alloy for Accurate Draw-Bend Simulation
,”
ASME J. Eng. Mater. Technol.
,
123
(
3
), pp.
287
292
.
5.
Song
,
H.
,
Wang
,
Z. J.
, and
He
,
X. D.
,
2013
, “
Improving in Plasticity of Orthorhombic Ti2AlNb-Based Alloys Sheet by High Density Electropulsing
,”
Trans. Nonferrous Met. Soc. China
,
23
(
1
), pp.
32
37
.
6.
Zheng
,
M.
,
Zhu
,
Y.
, and
Tang
,
G.
,
1998
, “
Comments on Electroplastic Drawing and Its Structure Evolution
,”
J. Tsinghua Univ. (Sci. Technol.)
,
38
(
2
), pp.
28
32
(in Chinese).
7.
Kinsey
,
B.
,
Cullen
,
G.
,
Jordan
,
A.
, and
Mates
,
S.
,
2013
, “
Investigation of Electroplastic Effect at High Deformation Rates for 304SS and Ti–6Al–4V
,”
CIRP Ann. Manuf. Technol.
,
62
(
1
), pp.
279
282
.
8.
Magargee
,
J.
,
Morestin
,
F.
, and
Cao
,
J.
,
2013
, “
Characterization of Flow Stress for Commercially Pure Titanium Subjected to Electrically-Assisted Deformation
,”
ASME J. Eng. Mater. Technol.
,
135
(
4
), p.
041003
.
9.
Ai
,
Z. Q.
,
Yan
,
L.
, and
Dong
,
X. H.
,
2015
, “
Study on Pure Electroplastic Effect of AZ31 Alloy and DP980 AHSS
,”
Hot Work. Technol.
,
44
(
4
), pp.
31
36
(in Chinese).
10.
Mai
,
J.
,
Peng
,
L.
,
Lin
,
Z.
, and
Lai
,
X.
,
2011
, “
Experimental Study of Electrical Resistivity and Flow Stress of Stainless Steel 316L in Electroplastic Deformation
,”
Mater. Sci. Eng., A
,
528
(
10
), pp.
3539
3544
.
11.
Roh
,
J. H.
,
Seo
,
J. J.
,
Hong
,
S. T.
,
Kim
,
M. J.
,
Han
,
H. N.
, and
Roth
,
J. T.
,
2014
, “
The Mechanical Behavior of 5052-H32 Aluminum Alloys Under a Pulsed Electric Current
,”
Int. J. Plast.
,
58
, pp.
84
99
.
12.
Ross
,
C. D.
,
Irvin
,
D. B.
,
Roth
,
J. T.
,
Ross
,
C. D.
,
Irvin
,
D. B.
, and
Roth
,
J. T.
,
2007
, “
Manufacturing Aspects Relating to the Effects of Direct Current on the Tensile Properties of Metals
,”
ASME J. Eng. Mater. Technol.
,
129
(
2
), pp.
342
347
.
13.
Ashtiani
,
H. R.
,
Bisadi
,
H.
, and
Parsa
,
M. H.
,
2014
, “
Influence of Thermomechanical Parameters on the Hot Deformation Behavior of AA1070
,”
ASME J. Eng. Mater. Technol.
,
136
(
1
), pp.
64
82
.
14.
Xie
,
H. Y.
,
Dong
,
X. H.
,
Peng
,
F.
,
Wang
,
Q.
,
Liu
,
K.
,
Wang
,
X. B.
, and
Chen
,
F.
,
2016
, “
Investigation on the Electrically-Assisted Stress Relaxation of AZ31B Magnesium Alloy Sheet
,”
J. Mater. Process. Technol.
,
227
, pp.
88
95
.
15.
Li
,
X. F.
,
Wang
,
S.
,
Zhao
,
S. J.
,
Ding
,
W.
,
Chen
,
J.
, and
Wu
,
G. H.
,
2015
, “
Effect of Pulse Current on the Tensile Deformation of SUS304 Stainless Steel
,”
J. Mater. Eng. Perform.
,
24
(
12
), pp.
5065
5070
.
16.
Abspoel
,
M.
,
Neelis
,
B. M.
, and
Liempt
,
P. V.
,
2016
, “
Constitutive Behavior Under Hot Stamping Conditions
,”
J. Mater. Process. Technol.
,
228
, pp.
34
42
.
17.
Zhao
,
K. M.
,
Fan
,
R.
, and
Wang
,
L. M.
,
2016
, “
The Effect of Electric Current and Strain Rate on Serrated Flow of Sheet Aluminum Alloy 5754
,”
J. Mater. Eng. Perform.
,
25
(
3
), pp.
781
789
.
18.
Goods
,
S. H.
, and
Brown
,
L. M.
,
1979
, “
Overview No. 1: The Nucleation of Cavities by Plastic Deformation
,”
Acta Metall.
,
27
(
79
), pp.
1
15
.
19.
Argon
,
A. S.
,
Im
,
J.
, and
Safoglu
,
R.
,
1975
, “
Cavity Formation From Inclusions in Ductile Fracture
,”
Metall. Mater. Trans. A
,
6
(
4
), pp.
825
837
.
20.
Puttick
,
K. E.
,
1959
, “
Ductile Fracture in Metals
,”
Philos. Mag.
,
4
(
44
), pp.
964
969
.
21.
Chawla
,
K. K.
,
1973
, “
Grain Boundary Cavitation and Sliding in Copper/Tungsten Composites Due to Thermal Stresses
,”
Philos. Mag.
,
28
(
2
), pp.
401
413
.
22.
Fan
,
H. J.
,
Chen
,
G. Q.
,
Zhou
,
W. L.
, and
Wu
,
C. W.
,
2006
, “
High Temperature Deformation Behavior of Niti Alloys in DC Electric Field
,”
Chin. J. Nonferrous Met.
,
16
(
6
), pp.
1012
1018
(in Chinese).
23.
Liu
,
Z.
,
Liu
,
B.
,
Deng
,
X.
,
Lei
,
Y.
,
Cui
,
J. Z.
, and
Bai
,
G. Y.
,
2000
, “
Effect of Current Pulse on Mechanism of Superplastic Deformation of 2091 Al-Li Alloy
,”
Acta Metall. Sin.
,
36
(
9
), pp.
944
954
(in Chinese).
You do not currently have access to this content.