Local melting and cracking in Al 7075-T6 and Al 2024-T3 friction stir spot welds

Abstract

Local melting of eutectic films and cracking is found in Al 2024 and Al 7075 alloy friction stir spot welds. Dissolution of melted films removes all evidence melted film formation in spot welds made using typical welding parameter settings. For this reason friction stir spot welding is carried out at a rapid plunge rate of 10 mm s⁻¹ and an extremely short dwell time of 0·05 s and after tool retraction, the welded samples are rapidly quenched using a mixture of methanol and liquid nitrogen at a temperature of −80°C. Eutectic films rich in Zn and Cu are formed in Al 7075 spot welds while melted Al₂CuMg particles promote the formation of α-Al+Al₂CuMg eutectic films in Al 2024 spot welds. Melted eutectic formation and cracking is also observed beneath the tip of the rotating pin during Al 7075 friction stir spot welding and is consistent with the occurrence of melt wear in this location.

Keywords

FRICTION STIR SPOT WELDING MELTING CRACKING AL2024 AL7075

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References

Hassan

K. A. A.

, Prangnell

P. B.

, Norman

A. F.

, Price

D. A.

and Williams

S. W.

: Sci. Technol. Weld. Join., 2003, 8, 257–268.

Yan

, Sutton

M. A.

and Reynolds

A. P.

: Sci. Technol. Weld. Join., 2005, 10, (6), 725–736.

North

T. H.

, Bendzsak

G. J.

, Smith

C. B.

and Luan

G. H.

: Proc. 7th Int. Symp. JWS, Kobe, Japan, November 2001, JWS, 621–632.

Gerlich

, Avramovic-Cingara

and North

T. H.

: Met. Trans. A., 2006, 37A, 2773–2786.

Gerlich

, Su

, Yamamoto

and North

T. H.

: J. Mater. Sci., 2007, DOI: 10.1007/s10583-006-1103-7.

Dalle-Donne

, Braun

, Staniek

, Jung

and Kayser

W. A.

: Materialwissenschaft und Werkstofftechnik, 1998, 29, 609–617.

Sato

Y. S.

, Hwan

, Park

, Michiuchi

and Kokawa

: Scr. Mater., 2004, 50, (9), 1233–1236.

Wert

J. A.

: Scr. Mater., 2003, 49, 607–612.

North

T. H.

, Bendzsak

G. J.

and Smith

C. B.

: Proc. 2nd Int. Conf. Friction Stir Welding, Paper 2, Session 7, proceedings on CDROM disc, Gothenburg, Sweden, June 2000, TWI.

10.

Gerlich

, Su

and North

T. H.

: in ‘Magnesium technology 2005’, (ed. N. R. Neelameggham et al.), 383–388; 2005, Warrendale, PA, TMS.

11.

Yamamoto

, Gerlich

, North

T. H.

and Shinozaki

: J. Mater. Sci., DOI: 10.1007/s10853-007-1662-2, 2007.

12.

Gerlich

, Su

and North

T. H.

: Sci. Technol. Weld. Join., 2005, 10, (6), 647–652.

13.

Gerlich

, Su

and North

T. H.

: J. Mater. Sci., 2005, 40, 6473–6481.

14.

Gerlich

, Su

, North

T. H.

and Bendzsak

G. J.

: Mater. Forum, 2005, 29, 290–294.

15.

Zhang

and Alpas

A. T.

: Acta Mater., 1997, 45, (2), 513–528.

16.

Chen

and Alpas

A. T.

: Wear, 2000, 246, 106–116.

17.

Liu

, Asthana

and Rohatgi

: J. Mater. Sci., 1991, 26, 99–102.

18.

, Gerlich

, North

T. H.

and Bendzsak

G. J.

: Sci. Technol. Weld. Join., 2006, 11, (2), 163–169.

19.

, Gerlich

, North

T. H.

and Bendzsak

G. J.

: Series

SAE Technical

, 2006-01–0971.

20.

Gerlich

, Yamamoto

and North

T. H.

: Met. Trans. A, 2007, to be published.

21.

Gerlich

, Yamamoto

and North

T. H.

: J. Mater. Sci., Special Edition on Join. Sci. Technol., 2007, to be published.

22.

Droenen

P.-E.

and Ryum

: Met. Trans. A, 1994, 25A, 521–530.

23.

Bjørneklett

, Frigaard

Ø.

, Grong

Ø.

, Myhr

O. R.

and Midling

O. T.

: Proc. 6th Int. Conf. on ‘Aluminium alloys’, Toyohashi, Japan, July 1998, The Japan Institute of Light Metals, 1531–1536.

24.

X.-M.

and Starink

M. J.

: Mater. Sci. Technol., 2001, 17, 1324–1328.

25.

Yamamoto

, Gerlich

, North

T. H.

and Shinozaki

: Sci. Technol. Weld. Join., 2007, Vol. 12, No. 3, pp. 208–216.

26.

Yamamoto

: ‘Research in progress’, Department of Materials Science and Engineering, University of Toronto, Toronto, Canada, March 2007.

27.

, Gerlich

, North

T. H.

and Bendzsak

G. J.

: Sci. Technol. Weld. Join., 2005, 11, (1), 61–71.

28.

Bendzsak

G. J.

, North

T. H.

and Li

: Acta Metall. Mater., 1997, 45, (4), 1735–1745.

29.

, Gerlich

, North

T. H.

and Bendzsak

G. J.

: Met. Trans. A, 2007, Vol. 38A, No. 3, pp. 584–595.

30.

Gerlich

, Su

, Bendzsak

G. J.

and North

T. H.

: in ‘Friction stir welding and processing III’, (ed. K. V. Jata et al.), 249–252; 2005, Warrendale, PA, TMS.

31.

Reiso

, Øverlie

H.-G.

and Ryum

: Met. Trans. A, 1990, 21A, 1689–1695.

32.

, Gerlich

and North

T. H.

: Series

SAE Technical

, 2005-01–1255.

33.

Kyffin

and Threadgill

: Proc. GKSS Int. Semin. on ‘Friction based spot welding processes’, Hamburg, Germany, March 2007, GKSS.

34.

Song

and Kovacevic

: Paper

SME Technical

MS02–175.

35.

Colegrove

P. A.

and Shercliff

H. R.

: Sci. Technol. Weld. Join., 2003, 8, (5), 360–368.

36.

Colegrove

P. A.

and Shercliff

H. R.

: Sci. Technol. Weld. Join., 2004, 9, (6), 483–492.

37.

Gerlich

, Su

, North

T. H.

and Bendzsak

G. J.

: Proc. Friction Stir Welding Colloquium, University of Graz, Austria, May 2006, 65–86.

38.

Colegrove

P. A.

, Shercliff

H. R.

and Threadgill

P. L.

: Proc. 4th Int. Conf. on ‘Friction stir welding’, Paper 3, Session 4B, proceeding on CDROM disc, Park City, UT, USA, May 2003, TWI.

39.

Frigaard

Ø.

, Grong

Ø.

, Hjelen

, Gulbrandsen-Dahl

and Midling

O. T.

: Proc. 1st Int. Symp. on ‘Friction stir welding’, Paper 2, Session 11, proceeding on CDROM disc, Thousand Oaks, CA, USA, June 1999, TWI.