摘要
In this study, the dissimilar friction stir welding （FSW） butt joints between aluminum alloy 5754-H114 and commerciallypure copper were investigated. The thickness of welded plates was 4 mm and the aluminum plate was placed on theadvancing side. In order to obtain a suitable flow and a better material mixing, a 1-mm offset was considered for thealuminum plate, toward the butt centerline. For investigating the microstructure and mechanical properties of FSWedjoints, optical microscopy and mechanical tests （i.e., uniaxial tensile test and microhardness） were used, respectively.Furthermore, the analysis of intermetallic compounds and fracture surface was examined by scanning electron microscopyand X-ray diffraction. The effect of heat generation on the mechanical properties and microstructure of the FSWed jointswas investigated. The results showed that there is an optimum amount of heat input. The intermetallic compounds formedin FSWed joints were A14Cu9 and AI2Cu. The best results were found in joints with 1000 rpm rotational speed and100 mm/min travel speed. The tensile strength was found as 219 MPa, which reached 84% of the aluminum base strength.Moreover, maximum value of the microhardness of the stir zone （SZ） was attained as about 120 HV, which was greatlydepended on the grain size, intermetallic compounds and copper pieces in SZ.
In this study, the dissimilar friction stir welding （FSW） butt joints between aluminum alloy 5754-H114 and commerciallypure copper were investigated. The thickness of welded plates was 4 mm and the aluminum plate was placed on theadvancing side. In order to obtain a suitable flow and a better material mixing, a 1-mm offset was considered for thealuminum plate, toward the butt centerline. For investigating the microstructure and mechanical properties of FSWedjoints, optical microscopy and mechanical tests （i.e., uniaxial tensile test and microhardness） were used, respectively.Furthermore, the analysis of intermetallic compounds and fracture surface was examined by scanning electron microscopyand X-ray diffraction. The effect of heat generation on the mechanical properties and microstructure of the FSWed jointswas investigated. The results showed that there is an optimum amount of heat input. The intermetallic compounds formedin FSWed joints were A14Cu9 and AI2Cu. The best results were found in joints with 1000 rpm rotational speed and100 mm/min travel speed. The tensile strength was found as 219 MPa, which reached 84% of the aluminum base strength.Moreover, maximum value of the microhardness of the stir zone （SZ） was attained as about 120 HV, which was greatlydepended on the grain size, intermetallic compounds and copper pieces in SZ.
