In order to investigate the interface phenomena, namely wettability, interface reaction, interfacial bonding, between Al₂O₃, and various Al alloys, wettability with the addition of alloying elements was measured by the dip coverage method, and the distribution of alloying elements and interfacial compounds at the interface were examined by using SEM-EDAX, Auger electron spectroscope and X-ray diffractometer. The interfacial bonding strength was also estimated by the indentation method. Wettability of Al was considerably improved by addition of Mg, Cu, Ni or Si. Among the four elements, Mg was the most effective. Mg was segregated at the interface of AC8A/Al₂O₃-20%SiO₂;the segregated Mg formed MgAl₂O₄, an interfacial compound. In pure Al/Al₂O₃ the inierface bonding strength was not affected by the concentration of SiO₂ in A1₂O₃ but in AC8A/Al₂O₃ the interface bonding strength increased with SiO₂ concentration and was 6.05 kgf/㎟ at 20%SiO₂.