Interaction of Al-Si, Al-Ge, and Zn-Al eutectic alloys with SiC/Al discontinuously reinforced metal matrix composites

Abstract

Interactions between Al-Si, Al-Ge, and Zn-Al eutectic alloys with SiC whisker-reinforced aluminium metal matrix composites were studied as a function of temperature above the eutectic melting temperature. Penetration extended several millimetres into the composite for the Al-Si and Al-Ge alloys but was restricted to a thin surface layer (50 μm) for the Zn-Al alloy. The extent of the penetration zone for the aluminium alloys containing silicon and germanium was also affected by the thermal-mechanical treatment of the composite: limited penetration was observed for hot-pressed material whereas extensive penetration was observed for mechanically worked material. Mechanisms for the observed phenomena are discussed in terms of the wettability of the SiC whiskers by the eutectic alloys, the formation of channels during mechanical working as well as the fine grain size of the composite.