Al-Al AND Al-Mg COMPOUND CASTING

摘要

'Compound casting' is a process where a melt is cast onto or around a solid metallic 'insert'. It is the realization of a simple joining procedure for light metals (Al-Al, Al-Mg) aiming at weight-saving. Difficulties inherent in joining aluminium are its natural oxide layer and the formation of intermetallic phases (IMPs). In this project, the solid substrate used is an aluminium alloy, and the melt is either aluminium, containing various alloying elements (Cu, Si, Zn), or magnesium. Compounds with flawless (lacking oxide and IMP) interfaces were produced successfully by replacing the oxide layer with a zinc layer. This was accomplished by pickling the substrate in a solution containing zincate ions, and by subsequent zinc galvanizing. Composition and mechanical properties were investigated by SEM/EDX and microhardness measurements after the 'compound casting' process and successive heat treatments.