A comparative investigation of butt friction stir welding of aluminium alloys, AA 1100 and AA 7075, with AISI 304 stainless steel

Abstract

Despite significant ongoing research in friction stir welding of dissimilar metals, comparison of friction stir weld- ability of different metals with any particular metal has been rarely reported. Such information may be important in design and manufacturing of engineering parts. The current work deals with butt friction stir welding of 2-mm-thick sheets of two different aluminium alloys with the same steel (AISI 304) with H13 steel tool. The aluminium alloys chosen were AA 1100 and AA 7075 which have different composition and properties. AA 1100 is commercially pure aluminium alloy (~ 99 weight % aluminium) whereas, AA 7075 is a highly alloyed aluminium alloy having Zn as the main alloying element. Design of experiments was used varying tool rotational speed and welding speed. The parameters significantly influenced the responses considered: ultimate tensile strength (UTS), % elongation at break and average micro-hardness of the weld region. Higher joint efficiency (84.58% of AA 1100) and % elongation (68.22% of AA 1100) was obtained for the AA 1100-AISI 304 welded assembly. For both the welded assemblies, slower welding speed produced better joint strength and ductility.