Influence of Processing Parameters on Induced Energy, Mechanical and Corrosion Properties of FSW Butt Joint of 7475 AA

Friction stir welding (FSW), a promising solid state joining process invented at TWI in 1991, was used to join 9 mm thick 7475 aluminum alloy which is considered essentially unweldable by fusion processes. In the present work, the process parameters such as tool rotational speed were varied from 300 to 1000 rpm for a travel speed of 50 mm/min and the influence of process parameters in terms of energy input on microstructure, hardness, tensile strength, and the corrosion property of 7475 aluminum joints was evaluated and analyzed. The maximum tensile strength of FSW joints was obtained at rotational speed of 400 rpm and traverse speed of 50 mm/min (59.2 kJ) which attributed maximum stirred zone area and maximum hardness. The maximum corrosion resistance properties of weld in 3.5% NaCl solution, however, were obtained at rotational speed of 1000 rpm and traverse speed of 50 mm/min. Furthermore, for a given weld, stirred zone showed improved corrosion properties than TMAZ.