Weld Quality Improvement with Hybrid FSW Technology Assisted by Preheating for Copper T2/Aluminium 5A06 Dissimilar Materials

Abstract

Copper and aluminium alloy could be welded by friction stir welding (FSW) but it is quite difficult to achieve a defect-free welding joint for welding dissimilar materials because of the enormous difference of their thermo-physical performances. In this paper, another friction stir tool was applied as a heating source to preheat the copper side to 150~200°C in the welding direction. Preheating temperature can make up the lost heat, improve the temperature of copper plate before the FSW process, achieve the refining grains, and then obtain a high quality welding joint. We concentrated on hybrid heat-source equipments design and procedure optimization in our studies. The microstructure, mechanical properties and phase constituents of FSW joints were studied through mechanical test and metallographic analysis. The results indicated that the hybrid FSW technology with preheating for copper T2/aluminium 5A06 dissimilar materials can not only improve the welding efficiency, but also obtain the high quality welding joint. This special welding technology could solve the welding problems of Al-Cu dissimilar materials and had a good potential for application in aerospace manufacturing.

Parametric effect on dissimilar friction stir welded steel-magnesium alloys joints: a review

“…Zhao et al [81] reported three different kinds of FSW tool probe namely; cylindrically tapered, cylindrically straight and cylindrical threaded for dissimilar aluminium-copper and derived that cylindrically tapered pin conveyed the maximum stabilities. The end profile of the tool probe may be domed or flat.…”

Auxiliary energy assisted friction stir welding – status review

“…This improves welding efficiency and good joint quality of the Cu-Al weld. 79,80 Summarising all the thermally assisted FSW processes discussed above, it is understood that the additional thermal energy in FSW contributes towards the improvement in the process variables, process efficiency, some mechanical properties and microstructure. However, the additional heating leads to some inherent disadvantages such as degradation of mechanical properties caused by the increase in HAZ and the growth of brittle precipitate phases and other undesirable phase transformations that would necessitate a compromise with the joint integrity.…”

Improving the joint strength of the friction stir spot welding of carbon steel and copper using the design of experiments method

“…Heating the tool during the welding process increased the shear tensile force and decreased the grain size in the welded zone of an AZ31 magnesium alloy joint (Shen et al , 2014). Pre-heating of copper improved the joint efficiency of aluminum alloy to copper (Zhao et al , 2012) and enhanced the weld quality (Sharma et al , 2017).…”