Ultrasound enhanced friction stir welding of aluminum and steel: Process and properties of EN AW 6061/DC04-Joints

doi:10.1016/j.jmst.2017.10.022

Abstract

Abstract:

In this work, the joining of aluminum to steel was conducted by ultrasound enhanced friction stir welding (USE-FSW). The power ultrasound was introduced into one of the metal sheets by an ultrasonic roll seam module synchronously to the FSW-process. The effect of the ultrasound on the resulting welds, their microstructure and their corrosion properties was investigated by light and scanning electron microscopy and corrosion investigations. The USE-FSW-joints showed less and smaller steel particles in the nugget zone as well as a thinner continuous intermetallic phase of FeAl₃ at the interface. The nondestructive testing method of computed laminography proved the observations made by optic microscopy due to non-porous joints for both techniques. Corrosion investigations showed only low corrosion current densities and no enhanced galvanic corrosion for the EN AW-6061/DC04-hybrid joints in sodium chloride solution.

Key words: Friction stir welding, Ultrasound enhancement, Dissimilar joints, Corrosion

Thom? Marco, Guntram Wagner, Stra? Benjamin, Bernd Wolter, Sigrid Benfer, Wolfram Fürbeth. Ultrasound enhanced friction stir welding of aluminum and steel: Process and properties of EN AW 6061/DC04-Joints[J]. J. Mater. Sci. Technol., 2018, 34(1): 163-172.

Figures/Tables 13

Table 1 Chemical composition of the investigated materials.

Material	Elements (wt%)
EN AW-6061 T6	Si	Fe	Cu	Mn	Mg	Cr	Zn	Ti	Al
	0.64	0.51	0.21	0.14	0.89	0.15	0.04	0.05	Bal.
DC04	C	Si	Mn	P	S	Al	Ti	Nb	Fe
	0.041	0.015	0.3	0.01	0.0077	0.49	0.0007	0.0037	Bal.

Fig. 1. Four axis machining center DMU80T extended for force-controlled FSW.

Fig. 2. Illustration of the USE-FSW configuration.

Fig. 3. Cross section images of a) aluminum/steel-FSW joints and b) aluminum/steel-USE-FSW joints.

Fig. 4. Particle in the nugget of an FSW-joint.

Fig. 5. EDX mapping of a particle in the nugget of an FSW-joint.

Fig. 6. IM-phase particle of a) an FSW-joint and b) an USE-FSW-joint.

Fig. 7. Interface between aluminum and steel a) FSW- and b) USE-FSW-joint.

Fig. 8. Computed laminography of a) FSW-joint, b) USE-FSW-joint.

Fig. 9. Volta-Potential maps of a FSW-joint (a) and an USE-FSW-joint (b) measured in air (relative humidity > 90%); time of each measurement: about 8 h starting from the top of the plot.

Fig. 10. Open circuit potential measured on different positions of a FSW-joint (a) and an USE-FSW-joint (b) in 0.5 molar NaCl solution.

Fig. 11. Potentiodynamic polarization curves measured on different positions of a FSW-joint (a) and an USE-FSW-joint (b) in 0.5 molar NaCl solution.

Fig. 12. Microscopic pictures of the measurement areas after the polarization measurements: EN AW-6061 Al alloy (a), Al-nugget of the FSW-joint (b) and the USE-FSW-joint (c), Al/steel transitional area of the FSW-joint (d) and the USE-FSW-joint (e) and DC04 steel (f).

References

[1]	M.F. Ruhstorfer, Rürreibschwei?n von Rohren, Ph.D. Thesis, MünchenUniversity of Technology, 2012.
[2]	M.K. Besharati Givi, P. Asadi, Advances in Friction-Stir Welding andProcessing, Elsevier Science & Technology, Cambridge, 2014.
[3]	T. Tanaka, T. Morishige, T. Hirata, Scripta Mater. 61(2009) 756-759.
[4]	H. Uzun, C. Dalle Donne, A. Argagnotto, T. Ghidini, C. Gambaro, Mater. Deses26(2005) 41-46.
[5]	Z. Shen, Y. Chen, M. Haghshenas, A.P. Gerlich, Jestech 18 (2015) 270-277.
[6]	T. Watanabe, H. Takayama, A. Yanagisawa, J. Mater. Process.Tech. 178(2006)342-349.
[7]	R.S. Coelho, A. Kostka, J.F. dos Santos, A.Kaysser-Pyzalla, Mater. Sci. Eng. 556(2012) 175-183.
[8]	M. Pourali, A. Abdollah-Zadeh, T. Saeid, F. Kargar, J. Alloy. Compd. 715(2017)1-8.
[9]	B. Strass, G. Wagner, C. Conrad, B. Wolter, S. Benfer, W. Fürbeth, Adv. Mater.Res.966-967(2014) 521-535.
[10]	O. KlagMikrostruktur, Mechanische Eigenschaften Und Korrosionsverhalten rührreibgeschwei?ter AZ91/AZ91- Und AZ91/AlMg3Mn-Verbunde, Ph.D Thesis Kaiserslautern University of Technology, 2013.
[11]	B. Strass, G. Wagner, D. Eifler, Mater. Sci.Forum 783-786(2014) 1814-1819.
[12]	P. Xue, D.R. Ni, D. Wang, B.L. Xiao, Z.Y. Ma, Mater. Sci. Eng. A 528 (2011)4683-4689.
[13]	P. Xue, B.L. Xiao, D.R. Ni, Z.Y. Ma, Mater. Sci. Eng. A 527 (2010) 5723-5727.
[14]	Y. Huang, Z. Lv, L. Wan, J. Shen, J.F. dos Santos, Mater.Lett. 207(2017)172-175.
[15]	W.A. Ferrando, The Concept of Electrically Assisted Friction Stir Welding(EAFSW) and Application to the Processing of Various Metals, DefenseTechnical Information Center, Fort Belvoir, VA, 2008.
[16]	M. Merklein, A. Giera, J. Int. Mater.Form. 1(2008) 1299-1302.
[17]	H. Bang, H. Bang, G. Jeon, I. Oh, C. Ro, Mater. Des. 37(2012) 48-55.
[18]	R. Lai, D. He, L. Liu, S. Ye, K. Yang, J. Int. Adv.Manuf. Technol. 73(2014)321-327.
[19]	X.C. Liu, C.S. Wu, J. Mater. Process.Tech. 225(2015) 32-44.
[20]	X.C. Liu, C.S. Wu, G.K. Padhy, Sci. Technol. Weld. Join. 20(2015) 345-352.
[21]	X. Liu, C. Wu, G.K. Padhy, Scripta Mater. 102(2015) 95-98.
[22]	Y. Rostamiyan, A. Seidanloo, H. Sohrabpoor, R. Teimouri, Acme 15 (2015)335-346.
[23]	L. Shi, C.S. Wu, X.C. Liu, J. Mater. Process.Technol. 222(2015) 91-102.
[24]	S. Amini, M.R. Amiri, Int. J. Adv. Manuf. Technol. 73(2014) 127-135.
[25]	K. Park, Development and Analysis of Ultrasonic Assisted Friction StirWelding Process, Ph.D Thesis, The University of Michigan, 2009.
[26]	S. Benfer, B. Stra?, G. Wagner, W. Fürbeth, Surf. Interface Anal. 48 (8) (2016)843-852.
[27]	U. Donatus, G.E. Thompson, X. Zhou, J. Wang, A. Cassell, K. Beamish, Mater.Charact. 107(2015) 85-97.
[28]	P.B. Srinivasan, W. Dietzel, R. Zettler, J. dos Santos, V.Sivan, Corros. Eng. Sci.Technol. 42(2007) 161-167.
[29]	Verein Deutscher Ingenieure ( VDI - Verlag, Computertomografie in derdimensionellen Messtechnik - Grundlagen und Definitionen, VDI/VDE 2630Blatt 1.1., Düsseldorf, VDI - Verlag, 2009.
[30]	C. Beine, C. Boller, U. Netzelmann, F. Porsch, R. Venkat, M. Schulze, A.Bulavinov, H. Heuer, 2nd International Symposium on NDT in AerospaceHamburg, 2010.
[31]	M. Maisl, C. Schorr, F. Porsch, U. Ha?er, Aachen (2010).
[32]	M. Stratmann, H. Streckel, Corr. Sci. 30 (6-7) (1990) 697-714.
[33]	M. Stratmann, H. Streckel, Corr. Sci. 30 (6-7) (1990) 681-696.
[34]	K. Wapner, B. Schoenberger, M. Stratmann, G. Grundmeier, J. Electrochem.Soc. 152 (3) (2005) E114-E122.
[35]	A. Aballe, M. Bethencourt, F.J. Botana, M. Marcos, J.M.Sánchez-Amaya, Corr.Sci. 46(2004) 1909-1920.