Quality of Interfaces in Cu/Al Dissimilar Friction-Stirred Welds

Abstract

The current work focuses on the particular case of dissimilar 6082 Al alloy/pure copper butt-friction stirred joints. It takes advantage of voluntarily non optimized welding conditions in order to test the potential of an original approach of identification of the welding defects by means of a single tensile test. The sequence and mechanism of the fracture events arise from their localization on the fracture surfaces thanks to strain maps obtained by digital image correlation. This technique of flaws identification is proved to be particularly efficient at least with the present highly damaged welds.

Critical review on friction stir welding of aluminium to copper

“…As displayed in Table 9, the brittle nature of the Al–Cu intermetallic phases is unanimously pointed to be the cause governing extensive cracking incidence in the Al–Cu friction stir welds. 19, 21, 22, 24, 32-34 , 36, 37, 39, 44, 46, 47, 50, 53, 60, 67, 68 In good agreement with this, it is well-established that the higher the intermetallic content of the welds, the more intense and severe is cracking. 32, 36, 50…”

“…Moreover, it is important to stress that the procedure adopted in most of the studies on Al-Cu FSW is in good agreement with the conclusions reached by Galvão et al, 34 Xue et al 21 and Liu et al 22 In fact, excluding a very small number of works, in which the reverse positioning of the plates was adopted, 35,36 the vast majority of researches conducted in this field are focussed on welds produced with the copper plate positioned at the advancing side of the welding joint. 23,30,32,[37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54] As displayed in Table 5, Akbari et al 55 investigated the effect of base materials positioning on Al-Cu friction stir lap weldability. Keeping all the other welding variables constant, the authors observed important differences in structural soundness of the welds by varying the base materials positioning.…”

“…Extreme brittleness of Al-Cu intermetallic phases Okamura and Aota, 19 Savolainen et al, 68 Ouyang et al, 36 Abdollah-zadeh et al, 24 Akinlabi et al, 37 Galvão et al, 32,34,50,60 Akinlabi and Akinlabi, 39 Liu et al, 22 Xue et al, 21 Avettand-Fenoël et al, 46,47 Liu et al, 53 Firouzdor and Kou, 67 Bisadi et al, 33 Al-Roubaiy et al 44…”

“…Moreover, it is important to stress that the procedure adopted in most of the studies on Al–Cu FSW is in good agreement with the conclusions reached by Galvão et al , 34 Xue et al 21 and Liu et al 22 In fact, excluding a very small number of works, in which the reverse positioning of the plates was adopted, 35, 36 the vast majority of researches conducted in this field are focussed on welds produced with the copper plate positioned at the advancing side of the welding joint. 23, 30, 32, 37-54…”

Comparison Study on Friction-Welded Cu-Al Material and Pure Cu/Al

“…Marie-Noelle Avettand-Fenoel's research results showed that the poor quality of interfaces linked to a lack of adhesion, initiates the fracture of dissimilar friction stirred welds. Both the intermetallic compounds and the softened zone, also present in the joint, are less deleterious [13]. However, for the application of friction-welded Cu-Al, no one knows the long-term performance of it and other necessary properties that we concern for use.…”