Experimental Study of Effective Parameters on Production and Mechanical Properties of Al- brass Bimetal Composite

In this study, aluminum- brass bimetal composite was produced by centrifugal casting process. Four preheat temperatures (100, 200, 300, and 400°C), three rotational speeds (800, 1600, and 2000 rotation-per-minute) and two volume ratios (1.5 and 2.5) are variables which have been investigated. Optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and X-ray diffraction analysis (XRD) were used for microstructure observations and phase characterization. Mechanical tests, based on Chalmers model, and fracture studies were performed on some specimens. According to the results, interface contains three discrete zones. Zone 1 includes diffusional layers (Al3Cu5Zn4- Al3Cu3Zn), zone 2 contains Al3Cu precipitates distributed in Al11Zn matrix, and at last zone 3 includes anomalous eutectic microstructure (α-Al/Al3Cu). Pressure test results showed that brittleness is associated with interface thickening so that bond strength is weakened. Interface fracture surface contains two fracture modes, brittle and ductile. Brittle fracture seems to be related to Al3Cu precipitates and ductile fractures to α-Al/Al3Cu anomalous eutectic microstructure.