Solidification Behaviour of Al-SiC Composite Foam

This paper describes the solidification behaviour of Al composite melt in the narrow cell wall region in Al foam. Aluminium alloy foams prepared through melt route essentially involve entrapment of gaseous phase in a high viscous liquid followed by solidification. During solidification, the composite melt present in the narrow channel amongst the gas bubbles largely restricts the flow of heat and composite melt solidifies in a restricted region covered by almost zero conducting phases. The solidification front velocity has been computed using different models and their results have been compared. The distribution of SiC particles and matrix microstructure has been evaluated and compared with the experimental observation. It is noted that the solidification front velocity is slowed down due to the presence of gas bubbles and solidification is expected to initiate within the melt away from the melt/bubble interface which facilitates pushing SiC particles towards the gas bubble/melt interface.