Effect of materials position on friction stir lap welding of Al to Cu

Abstract

Friction stir welding has been successfully used to weld the dissimilar metals. A few investigations have been carried out on the friction stir lap welding of Al to Cu, but the basic issue of how the position of the metals would affect the joint strength is still not resolved. In the present study, the 7070 Al and the commercially pure copper are lap joined using friction stir lap welding technology. Two test cases are considered. The distinction refers to the position of Al with respect to Cu. Microstructural analyses are carried out to gain intermetallic compounds and some microcracks. The effect of position of materials on the heat generation is investigated and justified through the temperature measurements. Mechanical properties of each sample are characterized using both shear and hardness tests. The results reveal that the maximum fracture load of the joint is obtained when Al is placed on the top of Cu.

Influence of Pin Length and Electrochemical Platings on the Mechanical Strength and Macroscopic Defect Formation in Stationary Shoulder Friction Stir Welding of Aluminium to Copper

“…While the intermixing is minimized at 1.8 mm, the extrusion of single copper fragments can be observed at 2 mm pin length. These fragments show a typical layer structure, which has repeatedly been observed in Al/Cu joints and identified as mostly intermetallic compounds [28][29][30]. It can be assumed that the pronounced IMC formation occurs when fragments are detached from the copper base material and are transported around the pin, presumably for numerous revolutions.…”

“…Galvao et al [28] observed increased intermixing, IMC formation and void formation for lap joints of pure copper and EN AW5083/AW6082, respectively, when copper is directly processed by the tool shoulder. Investigations of Akbari et al [29] showed an up to 26% increased peak temperature in this configuration. In terms of heat and wear minimization, most investigations are therefore carried out with aluminium as the top sheet.…”

The effect of reinforcement type on the microstructure, mechanical properties, and wear resistance of A356 matrix composites produced by FSP

“…FSP has been invented based on friction stir welding (FSW) for the microstructure modification of materials [7,8], which results in improving their mechanical and wear resistance. FSW as a welding technique has been used to weld different Al [8,[13][14][15][16], Mg [7,17,18], and Cu [13,19] alloys, some of which are classified as practically unweldable alloys in use of conventional welding methods. Different surface composites have been produced with different types of reinforcing particles like SiC [7,20], TiC [21], Al 2 O 3 [22], CNT [23][24][25], TiO 2 [26], and B 4 C [27].…”

Friction Stir Welding For Al-And Its Alloys

“…Whereas the welds produced under very high heat input conditions (high rotation speed and low traverse speed) presented formation of brittle intermetallic layers, in which strong micro-cracking takes place, the welds carried out under low heat input conditions (low rotation speedand high traverse speed) displayed incompletely welded interfaces. Akbari et al [3] analyzed the effect of base materials positioning on friction stir lap welding of 2 mm-thick plates of AA 7070 aluminium alloy to commercially pure copper. Welds produced with the aluminium alloy located on the top of joint and the copper at the bottom, as well as welds carried out with the reverse base materials positioning, were studied by the authors.…”