The high strength-to-weight ratio of magnesium alloys makes them attractive for automotive applications. These materials have been used for the engine cradle, seat frame, and shock tower applications to reduce vehicle weight. Despite these advantages, there are limiting factors to the application of magnesium alloys. One of these factors is the joining of magnesium alloys. Although there are various joining processes available, self-piercing riveting (SPR) is particularly promising. It provides not only the speed but also the necessary structural strength. However, because of the large amount of deformation associated with the process and the limited formability of magnesium at room temperature, SPR often results in part cracking of the riveted magnesium alloys, which reduces the part quality. In this study, a method of preheating the magnesium alloy before riveting was adopted to improve the joint quality. The fabrication of the desired SPR joints was investigated as a function of the preheat temperature and strain rate. To determine the optimum preheat temperature, Zener–Hollomon parameter was employed. Experiments were conducted to validate the proposed preheat temperature. Magnesium alloy AZ31 with a thickness of 2 mm was preheated with various temperatures prior to self-piercing riveting. The appearances, cross-sections, and mechanical tests of the SPR magnesium AZ31 joints were investigated. It was found that a preheat temperature of 180–200°C largely eliminated the discrepancies in SPR 2 mm thick magnesium AZ31 joints. The joint strength increases with increasing preheat temperature from ambient to 200°C. The strength increase is attributed to the reduction in joint discrepancies and an increase in mechanical interlock between the rivet and work pieces. The current findings on the development of a method can be used to determine the preheat temperature for self-piercing riveting of magnesium castings.

References

1.
Barnes
,
T. A.
, and
Pashby
,
I. R.
, 2000, “
Joining Techniques for Aluminum Spaceframes Used in Automobiles Part II—Adhesive Bonding and Mechanical Fasteners
”,
J. Mater. Process. Technol.
,
99
, pp.
72
79
.
2.
Yan
,
J.
,
Xu
,
Z.
, and
Li
,
Z.
, 2005, “
Microstructure Characteristics and Performance of Dissimilar Welds Between Magnesium Alloy and Aluminum Formed by Friction Stirring
”,
Scr. Mater.
,
53
, pp.
585
589
.
3.
Cai
,
W.
,
Wang
,
P. C.
, and
Yang
,
W.
, 2005, “
Assembly Dimensional Prediction for Self-Piercing Riveted Aluminum Panels
”,
Int. J. Mach. Tools Manuf.
,
45
, pp.
695
704
.
4.
Porcaro
,
R.
,
Hanssen
,
A. G.
, and
Langseth
,
M.
, 2006, “
Self-Piercing Riveting Process: An Experimental and Numerical Investigation
”,
J. Mater. Process. Technol.
,
171
, pp.
10
20
.
5.
Han
,
L.
,
Chrysanthou
,
A.
, and O’
Sullivan
,
J. M.
, 2006, “
Fretting Behavior of Self-Piercing Riveted Aluminum Alloy Joints Under Different Interfacial Conditions
”,
Mater. Des.
,
27
, pp.
200
208
.
6.
Fu
,
M.
, and
Mallick
,
P. K.
, 2003, “
Fatigue of Self-Piercing Riveted Joints in Aluminum Alloy 6111
”,
Int. J. Fatigue
,
25
, pp.
183
189
.
7.
Han
,
L.
, and
Chrysanthou
,
A.
, 2008, “
Evaluation of Quality and Behavior of Self-Piercing Riveted Aluminum to High Strength Low Alloy Sheets With Different Surface Coatings
”,
Mater. Des.
,
29
, pp.
458
468
.
8.
Han
,
L.
,
Chrysanthou
,
A.
, and
Young
,
K. W.
, 2007, “
Mechanical Behavior of Self-Piercing Riveted Multi-Layer Joints Under Different Specimen Configurations
”,
Mater. Des.
,
28
, pp.
2024
2033
.
9.
Han
,
L.
,
Young
,
K. W.
, and
Chrysanthou
,
A.
, 2006, “
The Effect of Pre-Straining on the Mechanical Behavior of Self-Piercing Riveted Aluminum Alloy Sheets
”,
Mater. Des.
,
27
, pp.
1108
1113
.
10.
Fu
,
M.
, and
Mallik
,
P. K.
, 2001, “
Effect of Process Variables on the Static and Fatigue Properties of Self-Piercing Riveted Joints in Aluminum Alloy 5754
”,
Society of Automotive Engineers, SAE Paper, No.2001- 01-0825
.
11.
Abe
,
Y.
,
Kato
,
T.
, and
Mori
,
K.
, 2006, “
Joinability of Aluminum Alloy and Mild Steel Sheets by Self Piercing Rivet
”,
J. Mater. Process. Technol.
,
177
, pp.
417
421
.
12.
Lian-fa
,
Y.
,
Ken-ichiro
,
M.
, and
Hirokazu
,
T.
, 2008, “
Deformation Behaviors of Magnesium Alloy AZ31 Sheet in Cold Deep Drawing
”,
Trans. Nonferrous Met. Soc.
,
18
, pp.
86
91
.
13.
Watanabe
,
H.
,
Tsutsui
,
H.
, and
Mukai
,
T.
, 2001, “
Deformation Mechanism in a Coarse-Grained Mg–Al–Zn Alloy at Elevated Temperatures
”,
Int.J.Plast.
,
17
, pp.
387
397
.
14.
Jäger
,
A.
,
Lukáč
,
P.
, and
Gärtnerová
,
V.
, 2004, “
Tensile Properties of Hot Rolled AZ31 Mg Alloy Sheets at Elevated Temperatures
”,
J. Alloys Compd.
,
378
, pp.
184
187
.
15.
Fuh-Kuo
,
C.
,
Tyng-Bin
,
H.
,
Chih-Kun
,
C.
, 2003, “
Deep Drawing of Square Cups With Magnesium Alloy AZ31 Sheets
”,
Int. J. Mach. Tools Manuf.
,
43
, pp.
1553
1559
.
16.
Zhang
,
S. H.
,
Zhang
,
K.
, and
Xu
,
Y. C.
, 2003, “
Deep-Drawing of Magnesium Alloy Sheets at Warm Temperatures
”,
Int. J. Mach. Tools Manuf.
,
43
, pp.
1553
1559
.
17.
Abdel Maksouda
,
I.
,
Ahmedb
,
H.
, and RÖ
dela
,
J.
, 2009, “
Investigation of the Effect of Strain Rate and Temperature on the Deformability and Microstructure Evolution of AZ31 Magnesium Alloy
”,
Mater. Sci. Eng.
,
504
, pp.
40
48
.
18.
Peng
,
W. P.
,
Li
,
P. J.
, and
Zeng
,
P.
, 2008, “
Peng
,
W. P.
,
Li
,
P. J.
, and
Zeng
,
P.
, 2008, “
Hot Deformation Behavior and Microstructure Evolution of Twin-Roll-Cast Mg–2.9Al–0.9Zn Alloy: A Study With Processing Map
”,
Mater. Sci. Eng.
,
494
, pp.
173
178
.
19.
Beer
,
A. G.
, and
Barnett
,
M. R.
, 2006, “
Influence of Initial Microstructure on the Hot Working Flow Stress of Mg–3Al–1Zn
”,
Mater. Sci. Eng.
,
423
, pp.
292
299
.
20.
Beer
,
A. G.
, and
Barnett
,
M. R.
2009, “
The Post-Deformation Recrystallization Behavior of Magnesium Alloy Mg–3Al–1Zn
”,
Scr. Mater.
,
61
, pp.
1097
1100
.
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