Microstructural and mechanical characteristics of friction stir welded Al6101/C11000 joints with zinc and silver interlayer.

This manuscript presents the microstructure and mechanical analysis of friction stir welded joints of Al 6101 (aluminum alloy) and C11000 (copper alloy) plates of 3 mm thickness with and without incorporation of silver (Ag) and zinc (Zn) interlayers. Four joints ( J 1 : Al-Cu), ( J 2 : Al-Ag–Cu), ( J 3 : Al-Zn-Cu), and ( J 4 : Al-Ag-Zn-Cu) have been made between Al-Cu plates by the FSW process. The quality of welded joints has been inspected using tensile testing, scanning electron microscopy, and energy-dispersive X-ray analysis (EDX). The Al-Cu joint made with hybrid interlayers (silver and zinc) has the highest tensile strength with a value of 121.78 ± 6.34 MPa, which is 36.44% greater than joint J 1 without interlayer, 7.32% greater than joint J 2 with Ag interlayer, and 21.97% greater than joint J 3 with Zn interlayer. Improvement in tensile strength is due to the formation and uniform distribution of Zn-generated thin intermetallic and the distribution of Ag-generated ductile Ag 2 Al intermetallic in the weld zone. Fractographic analysis on tensile sample supports the reason for achieving high tensile strength for joints with hybrid interlayer, where the combination of small and large dimples was noted, which confirm the ductile mode of fracture compared with other joints. Microstructural studies revealed the flow variation of constituents with and without interlayers. EDX analysis confirmed the formation of binary and ternary intermetallic phases. The diffusion of interlayers with Al/Cu parent metal has reduced the formation of detrimental brittle intermetallic between the parent metals. Line scan and elemental mapping show that the joints with Zn and Ag interlayer have thin, continuous, and uniform intermetallics with improved metallurgical and mechanical properties of the welds. [ABSTRACT FROM AUTHOR]