In this study, an aluminum-aluminum macrocomposite bimetal (Al-4.5wt.%Cu/C.P. aluminum) was successfully fabricated and characterized by compound squeeze casting process. The effects of three process variables, i.e. surface patterning of the solid insert (squeeze cast Al-4.5wt.%Cu alloy), intensity of the applied pressure and pouring temperature of C.P. aluminum on the microstructure and mechanical properties of the interface region were investigated by optical microscopy (OM), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) as well as tensile, shear and microhardness tests. Microstructural and EDS analyses showed an evident transition zone across the interface of the bimetals when a special concentric groove pattern was machined on the top surface of the squeeze cast Al-4.5wt.%Cu inserts. Simulation results showed that the machined grooves resulted in formation of large stress gradient fields along the interface region of the bimetals which is believed to result in rapture of the oxide layer facilitating the formation of a transition zone between the bimetal parts. Average thickness of the transition zone of the bimetals produced after surface patterning of the inserts under applied pressures of 70 and 50 MPa, were 375 and 385 ?m, and the average tensile strength of these bimetals were about 54 and 52 MPa, respectively. The process presented in this study is a low cost and promising approach for fabrication of macrocomposite bimetals without resort to any prior chemical treatments of the insert.
