Effect of SiO 2 content in AI 2 O 3 on interfacial bonding strength of aiuminium/AI 2 ) 3 composite

Abstract

In this study, the interfacial bonding strength between pure aluminium or an aluminium alloy (Al-12Si-1Cu-1Mg-2Ni) and Al₂O₃ containing 0-20 wt-%SiO₂ was measured using a B scale Rockwell hardness indenter. The interface was analysed using scanning electron microscopy, Auger electron spectroscopy, and X-ray diffraction. The results obtained were as follows. In the pure aluminium/Al₂O₃ composite the interfacial bonding strength was not strongly affected by the SiO₂ additions, but the interfacial strength of the aluminium alloy/Al₂O₃ composite could be significantly improved by small additions (2-5 wt-%) of SiO₂ in the Al₂O₃. Magnesium was the only alloying element to segregate at the interface. At the interface of the pure aluminium/Al₂O₃–20SiO₂ specimen, Al₂O₃ and silicon were detected, and MgAl₂O₄ and Al₂O₃ were detected in the aluminium alloy/Al₂O₃–20SiO₂ specimen. The interfacial chemical reaction involving magnesium is believed to be important in increasing the interfacial bonding strength.